JP2002070973A - Friction roller type transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent generation of remarkable abrasion on the outer circumferential surfaces of a wedge roller 10 and guide rollers 11a, 11b at an overrun time when an outer ring 13b rotates while a center roller 25a is stopped. SOLUTION: The wedge roller 10 and the guide rollers 11a, 11b are manufactured from ceramics, or nitriding or phosphoric acid coating is applied on the outer circumferential surfaces of each roller 10, 11a, 11b. Otherwise, a coat of DLC is formed on a desired circumferential surface. The outer circumferential surfaces of each roller 10, 11a, 11b becomes hardly abraded by this formation.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION A friction roller type transmission according to the present invention is incorporated in a driving part of an auxiliary machine for an automobile such as an alternator, a compressor and various hydraulic pumps, and is driven to rotate by a crankshaft of an engine. The rotation of the driven pulley is transmitted to the rotating shaft of the accessory while decelerating, and is used to rotationally drive the accessory.

[0002]

2. Description of the Related Art Auxiliary equipment for automobiles is driven to rotate by a traveling engine. There are a plurality of auxiliary equipment driven by a single traveling engine. May be different. In addition, the optimum driving speed of each of these accessories may be different from the rotation speed of the traveling engine. For this reason, conventionally, the diameter of the drive pulley fixed to the end of the crankshaft of the traveling engine and the diameter of each driven pulley fixed to the end of the rotating shaft of each of the auxiliary machines are made different from each other, The rotational speed of each of these accessories is set to a preferable value. Further, by using a driven pulley having a built-in one-way clutch, the direction of the frictional force applied to the endless belt stretched between each driven pulley and the driving pulley is kept constant, and thus the endless belt is driven. In addition to ensuring the durability of the endless belt, it is also possible to prevent the rotation speed of the rotating shaft of each of the above-mentioned auxiliary equipments from decreasing even when the speed of the endless belt tends to decrease, and to improve the efficiency of each of these auxiliary equipments. This has been done conventionally.

However, by changing the diameter of the driving pulley and the diameter of the driven pulley, the rotational speed of each of the above-mentioned auxiliary machines is adjusted by securing the amount of winding of the endless belt around each of the pulleys, Limiting the amount of bending (without reducing the radius of curvature) to ensure its durability is limited. On the other hand, in recent years, the use of a friction transmission having a clutch mechanism to construct a rotary drive device for the accessory has been studied. Conventionally, a friction roller type transmission meeting such conditions has been disclosed in Japanese Patent Laid-Open No. 10-3160.
No. 81, No. 10-329780 and the like are known.

According to the publications described in these publications, a conventionally known friction roller type transmission is considered as an auxiliary power source of an electric assist bicycle, and a rotary shaft of an electric motor assists a pedal shaft. When power is applied, when the rotation speed of the pedal shaft becomes faster than the rotation speed of the rotation shaft of the electric motor, the rotation of the pedal shaft is not transmitted to the rotation shaft. . FIG.
8 is considered for such a purpose, and is disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 10-31.
No. 6081, a friction roller type transmission
An example is shown. First, the conventional structure will be described.

[0005] The electric motor 1 as a drive source has a rotating shaft 2 corresponding to the input shaft described in the claims. The tip of the rotating shaft 2 functions as a center roller described in the claims. That is, in the structure described in FIGS.
The input shaft and the center roller are formed as an integral rotating shaft 2. The outer peripheral surface of the distal end portion, which corresponds to the first cylindrical surface described in the claims, is a smooth cylindrical surface.
The housing 3 is provided so as to cover the leading end of the rotating shaft 2 serving as a center roller.
In use, the housing 3 is fixed to a frame (not shown) or the like. The housing 3 has a bottomed cylindrical main body 4.
And a lid 5 for closing the base opening of the main body 4.
The distal end of the rotary shaft 2 of the electric motor 1 is inserted into the housing 3 through a through hole 6 formed substantially at the center of the lid 5. The through hole 6 is provided at a position slightly deviated from the center of the lid 5 as described later. A bearing 7 is provided between the inner peripheral surface of the through hole 6 and the outer peripheral surface of the intermediate portion of the rotary shaft 2.

In addition, three support shafts 8 and 8a are arranged inside the housing 3 and around the rotary shaft 2 in parallel with the rotary shaft 2. That is, one end (upper end in FIG. 7) of each of the support shafts 8 and 8a is supported by the lid 5, and the other end (lower end in FIG. 7) is supported by the connecting ring 9. In addition, of these three support shafts 8 and 8a, the two support shafts 8 and 8 are press-fitted or substantially fixed at both ends into fitting holes provided in the lid 5 and the connecting ring 9, respectively. Inserted without sticking. Therefore, these two support shafts 8, 8 are not displaced in the circumferential direction or the diametric direction in the housing 3. On the other hand, the remaining one support shaft 8a has both ends with respect to the lid 5 and the connecting ring 9.
The housing 3 is supported so as to be slightly displaceable in the circumferential direction (and, if necessary, in the diametrical direction). For this purpose, a part of the lid 5 and the connecting ring 9 which is aligned with both ends of the support shaft 8a is provided with a circular arc-shaped engagement groove or a support shaft 8a which is long in the circumferential direction of the housing 3. Support holes (not shown in FIGS. 7 and 8) having an inner diameter larger than the outer diameter of both ends are formed, and both ends of the support shaft 8a are loosely engaged with both engagement grooves or support holes. . And
A wedge roller 10 and a guide roller 1 each serving as an intermediate roller
Each of 1a and 11b is rotatably supported by a bearing 18 (see FIG. 7; omitted in FIG. 8). A part of the connecting ring 9 is a part of an inner surface of the lid 5 (a surface on the space side where the wedge roller 10 and the guide rollers 11a and 11b are installed, and a lower surface in FIG. 7). Also, it is connected to the tip of a protrusion 12 (see FIG. 7; omitted in FIG. 8), which protrudes from the guide rollers 11a and 11b.

A cylindrical outer ring 13 with a bottom is rotatably provided inside the housing 3 at a portion surrounding the wedge roller 10 and the guide rollers 11a and 11b. The outer ring 13 includes a cylindrical portion 14 and a disk portion 15 that closes an opening of one end (the lower end in FIG. 7) of the cylindrical portion 14.
Of these, the inner peripheral surface of the cylindrical portion 14 corresponding to the second cylindrical surface described in the claims is a smooth cylindrical surface, which is also a smooth cylindrical surface. Corresponding wedge roller 10 and guide roller 11
a and 11b can be freely contacted with the outer peripheral surface. The outer surface of the disk portion 15 (the side opposite to the space where the wedge roller 10 and the guide rollers 11a and 11b are installed, the lower surface in FIG. 7) is provided at the base end of the output shaft 16 (the upper end in FIG. 7). Part)
Is fixed. The output shaft 16 is inserted into a second through hole 17 provided at the center of the main body 4 constituting the housing 3 and protrudes out of the housing 3. A bearing 23 is provided between the outer peripheral surface of the output shaft 16 near the proximal end and the inner peripheral surface of the second through hole 17.
The outer ring 13 and the output shaft 16 are rotatably supported with respect to the housing 3. A pinion 19 is fixed to a portion of the output shaft 16 that protrudes out of the housing 3 in the first half (lower half of FIG. 7).

The outer peripheral surfaces of the wedge roller 10 and the guide rollers 11a and 11b are in contact with the outer peripheral surface of the tip of the rotary shaft 2 and the inner peripheral surface of the outer ring 13. However,
The center of the rotation shaft 2 and the centers of the output shaft 16 and the outer ring 13 are eccentric to each other. That is, as described above, the through hole 6 for inserting the rotary shaft 2 is provided at a position slightly deviated from the center of the housing 3, whereas the second hole for inserting the output shaft 16 is provided. The hole 17 is provided at the center of the housing 3. The output shaft 16 supported inside the second through hole 17 and the outer ring 13 are concentric with each other. Therefore, the rotating shaft 2 and the outer ring 13 and the output shaft 16 are eccentric with respect to each other by an amount of deviation δ of the through hole 6 from the center of the housing 3. The wedge roller 10 and the guide rollers 11a and 11b exist between the outer peripheral surface of the rotary shaft 2 and the inner peripheral surface of the outer ring 13.
The width dimension of the annular space 20 provided with is uneven in the circumferential direction by an amount corresponding to the amount of eccentricity δ.

In this manner, the width of the annular space 20 is made unequal in the circumferential direction, so that the wedge roller 10
The guide rollers 11a and 11b have different outer diameters. That is, the diameters of the wedge roller 10 and the guide roller 11a (small-diameter guide roller) located on the side (left side in FIG. 8) where the rotation shaft 2 is eccentric with respect to the outer ring 13 are made equal to each other and relatively small. I have. On the other hand, the diameter of the guide roller 11b (large-diameter guide roller) located on the opposite side (right side in FIG. 8) of the outer ring 13 from the eccentricity of the rotary shaft 2 is determined by the wedge roller 10 and the guide roller 11a Larger than. Then, these three wedge rollers 1 each being an intermediate roller
0 and the outer peripheral surfaces of the guide rollers 11a and 11b are brought into contact with the outer peripheral surface of the rotary shaft 2 and the inner peripheral surface of the outer ring 13.

The above-mentioned 1 is an intermediate roller.
Wedge rollers 10 and two guide rollers 11
The supporting shafts 8 supporting the guide rollers 11a and 11b are fixed in the housing 3 as described above. On the other hand, the support shaft 8a supporting the wedge roller 10 freely supports a slight displacement of the housing 3 in the circumferential direction in the housing 3 as described above. Therefore, the wedge roller 10 can also be displaced in the housing 3 in the circumferential direction of the housing 3. When the rotating shaft 2 rotates in a predetermined direction, the wedge roller 10 rotatably supported by the one support shaft 8a is moved to the annular space 20.
It can be moved toward the narrow part. The wedge roller 10 is provided with a spring 24 (see FIG. 11 described later).
Thereby, the annular space 20 is pressed toward the narrow portion.

That is, in the example shown in FIG.
As shown by the arrow a, rotate clockwise in FIG.
The assembly direction of each component is regulated. Therefore, when power is taken out from the electric motor 1 to the output shaft 16, the wedge roller 10 and the guide roller 11a,
11b rotates counterclockwise in FIG. 8 around the support shafts 8a and 8 as indicated by arrows B and B in FIG. 8, and the outer ring 13 also moves counterclockwise as indicated by arrows C in FIG. Rotate.
In this manner, the one wedge roller 10 rotates as shown by the arrow B, and the rotating shaft 2 and the outer ring 13 which hold the wedge roller 10 from both the inner and outer sides in the diametric direction of the housing 3 respectively show the arrows A and C. As a result of rotating as shown in
The wedge roller 10 has a tendency to be displaced clockwise in FIG. 8, as indicated by an arrow d in FIG. That is, the wedge roller 10 receives the force in the direction indicated by the arrow from the rotating shaft 2 rotating in the direction indicated by the arrow a, and the wedge roller 10 rotates in the direction indicated by the arrow B to contact the inner peripheral surface of the outer ring 13. Due to the reaction from the contact portion, the force in the direction indicated by the arrow D is also received. As a result, the wedge roller 10 tends to move toward the narrow portion of the annular space 20 when the rotation shaft 2 rotates.

In the case of the friction roller type transmission constructed as described above, the rotation of the rotating shaft 2 of the electric motor 1
Of the wedge roller 10 and the guide rollers 11a, 11b, which are intermediate rollers, and the inner peripheral side abutting portions 21, 21, which are the abutting portions of the wedge roller 10 and the guide rollers 11a, 11b, respectively. Rollers 11a, 11b
It is transmitted to. Further, the rotation of the wedge roller 10 and the guide rollers 11a and 11b is caused by the contact between the outer peripheral surfaces of the wedge roller 10 and the guide rollers 11a and 11b and the inner peripheral surface of the outer ring 13, that is, each outer diameter side contact. Contact 2
The power is transmitted to the outer ring 13 via 2 and 22. Then, the output shaft 16 fixed to the outer ring 13 and the pinion 19 fixed to the output shaft 16 rotate.

When the rotating shaft 2 and the outer ring 13 rotate in a predetermined direction, a wedge roller 10 rotatably supported by a single support shaft 8a moves the outer circumferential surface of the rotating shaft 2 and the inner circumferential surface of the outer ring 13 to each other. In the annular space 20 existing therebetween, it moves in a direction indicated by an arrow D in FIG. 8 toward a narrow portion of the annular space 20. As a result, the outer peripheral surface of the wedge roller 10 rotatably supported by the one support shaft 8a strongly presses the outer peripheral surface of the rotary shaft 2 and the inner peripheral surface of the outer ring 13. Then, an inner diameter side contact portion 21 which is a contact portion between the outer peripheral surface of the wedge roller 10 and the outer peripheral surface of the rotary shaft 2, and a contact between the outer peripheral surface of the wedge roller 10 and the inner peripheral surface of the outer ring 13. The contact pressure of the outer diameter side contact portion 22, which is the contact portion, increases.

As described above, when the contact pressure of the inner and outer contact portions 21 and 22 with respect to the wedge roller 10 increases, each of the members is pressed by the outer peripheral surface of the wedge roller 10. At least one member of the rotating shaft 2 and the outer ring 13 is slightly displaced in the respective diametrical directions based on an assembling gap or elastic deformation. As a result, two inner-diameter-side contact portions 21, 21 which are contact portions between the outer peripheral surfaces of the guide rollers 11 a, 11 b and the outer peripheral surface of the rotary shaft 2, which are the remaining two intermediate rollers, and The contact pressure of the two outer diameter side contact portions 22, 22 which is the contact portion between the outer peripheral surface of each of the guide rollers 11 a and 11 b and the inner peripheral surface of the outer ring 13 increases. Then, the clutch mechanism is connected, and the rotational force is efficiently transmitted from the rotating shaft 2 to the outer ring 13.

On the other hand, when the outer ring 13 is rotating in the direction indicated by the arrow C in FIG. 8 even though the rotating shaft 2 is stopped, or when the rotating speed matches the rotating speed of the rotating shaft 2. When the outer ring 13 is rotating in a direction indicated by an arrow C in FIG. 8 at a rotation speed higher than the speed (the product of the rotation speed of the rotating shaft 2 and the gear ratio of the friction roller type transmission), the outer ring 13
To prevent the rotation from being transmitted to the rotating shaft 2. That is,
In this case, the outer ring 1 rotating in the direction of arrow C in FIG.
3, the wedge roller 10 is displaced in the direction opposite to the arrow d in FIG. As a result, this wedge roller 10
Does not press the outer peripheral surface of the rotating shaft 2 and the inner peripheral surface of the outer ring 13, and the contact pressure of the inner diameter side contact portion 21 and the outer diameter side contact portion 22 is reduced or lost. And
The connection of the clutch mechanism is disconnected, and a so-called overrun state in which rotation is not transmitted from the outer ring 13 to the rotating shaft 2 is obtained.

[0016]

In the case of the friction roller type transmission constructed and operated as described above, when the outer ring 13 rotates with the clutch mechanism disconnected (at the time of overrun), the wedge is formed. Roller 10 and each guide roller 11
There is a possibility that the outer peripheral surfaces of the a and 11b and the inner peripheral surface of the outer ring 13 or the outer peripheral surface of the rotating shaft 2 may rub against each other. That is, in the case of the conventional structure, the wedge roller 10 is pressed against the narrow side of the annular space 20 by the spring 24 (see FIG. 11 described later), and the outer peripheral surfaces of the guide rollers 11a and 11b and the outer ring 13 and the outer peripheral surface of the rotating shaft 2 are lightly abutted (a state in which rotational force cannot be transmitted due to frictional engagement). When the rotational force is transmitted from the rotating shaft 2 to the outer ring 13, the wedge roller 10 is made to bite into a narrow portion of the annular space 20 in a wedge shape, and the guide rollers 11a are formed based on the elastic deformation of each portion. , 11b, the inner peripheral surface of the outer race 13 and the outer peripheral surface of the rotary shaft 2 are in strong contact with each other. Therefore, when the outer ring 13 rotates with the connection of the clutch mechanism disconnected, the outer peripheral surfaces of the wedge roller 10 and the guide rollers 11a and 11b rub against the inner peripheral surface of the outer ring 13 (instead of rolling contact). With respect to the outer peripheral surface of each of the guide rollers 11a and 11b, a minute clearance can be interposed between the guide roller 11a and the inner peripheral surface of the outer ring 13 at the time of overrun by adjusting the assembling clearance. Such a minute gap cannot be set for the outer peripheral surface.

When the bicycle is used at a low speed (for example, when the rotation speed of the output unit is about 600 min ^-1 (rpm)) as in an electric assist bicycle, even if the above-mentioned rubbing occurs, no particular problem occurs. . On the other hand, high speed (for example, when the rotation speed of the output unit is 10,000 min.
^In the case of a mechanical device used at about ^-1 ), when the above-mentioned friction occurs, non-negligible wear (abnormal wear) occurs at the frictional portion. In addition, due to the abnormal wear, slipping, abnormal noise, or seizure occurs inside the friction roller type transmission, and the durability of the mechanical device cannot be sufficiently ensured.

In order to confirm this point, the present inventor:
As schematically shown in FIG. 9, while the center roller 25 of the friction roller type transmission is fixed, the outer ring 1 is driven by the output shaft 16a.
A so-called overrun test in which 3a was rotated was performed.
After the overrun test was continued for a predetermined time (several minutes), the friction roller type transmission was disassembled, and the wear of each component was visually checked. As a result, FIG.
As shown by the oblique lattice, intermediate rollers (wedge roller 10 and guide roller 1) constituting this friction roller type transmission are shown in FIG.
A part of the outer peripheral surface of 1a, 11b) was worn in the circumferential direction. On the other hand, the outer peripheral surface of the center roller 25 and the inner peripheral surface of the outer ring 13a were hardly worn.

The reason why only a part of the outer peripheral surface of the intermediate roller is worn during the overrun can be considered as follows. When the outer ring 13a is rotated while the center roller 25 is fixed as shown in FIG. 9, the wedge roller 10 has a frictional force acting between the outer ring 13a and the inner peripheral surface of the outer ring 13a as shown in FIG. Accordingly, the spring tends to be displaced against the preload spring 24. However, the force for this displacement is obtained by friction between the inner ring of the outer ring 13a and the outer ring 13a.
The outer peripheral surface of the wedge roller 10 does not remain completely separated from the inner peripheral surface of the outer ring 13a. Because of this,
During the overrun, the outer peripheral surface of the wedge roller 10 and the inner peripheral surface of the outer ring 13a rub with a small contact pressure (P) and a high sliding speed (V). As a result, the PV value (the product of the contact pressure P and the sliding speed V) of the rubbed portion between the two peripheral surfaces increases, and wear occurs.

In this case, the inner peripheral surface of the outer ring 13a is uniformly rubbed over its entire circumference, so that significant wear does not occur locally. On the contrary,
During the overrun, the wedge roller 10 is set to (0.1
Because it rotates only at a very low speed (in min ^-1 units), partial wear occurs, as shown in FIG. Such partial wear must be avoided because it deteriorates the performance of the friction roller type transmission.

The guide rollers 11a and 11b are not pushed by a spring for preloading.
There is a case where the inner peripheral surface of a is lightly contacted. In such a case, partial wear occurs as shown in FIG. The contact portion between the outer peripheral surface of the wedge roller 10 and each of the guide rollers 11a and 11b and the outer peripheral surface of the center roller 25 has an extremely small contact pressure (P) and extremely low sliding speed (V). Therefore, the PV value is also reduced, and the problematic wear does not occur. In view of such circumstances, the friction roller type transmission of the present invention has the wedge roller 10 and the guide rollers 11a and 11b as intermediate rollers.
Has been invented in order to prevent the outer peripheral surface from being worn.

[0022]

All of the friction roller type transmissions according to the present invention have an input shaft and an end portion of the input shaft similar to the above-described conventionally known friction roller type transmission. A central roller provided concentrically with the input shaft and having an outer peripheral surface as a first cylindrical surface and an inner peripheral surface as a second cylindrical surface around the central roller and freely rotating relative to the central roller. The center roller in an annular space between the first cylindrical surface and the second cylindrical surface, and an output shaft substantially concentric with the outer ring and having one end coupled to the outer ring. And a plurality of intermediate rollers rotatably supported by the respective support shafts and having respective outer peripheral surfaces as third cylindrical surfaces. The center of the center roller and the center of the output shaft and the outer ring are eccentric to make the width of the annular space unequal in the circumferential direction. At least one of the plurality of intermediate rollers is supported so as to be displaceable at least in the circumferential direction of the annular space, and is a wedge roller, and the remaining intermediate rollers are guide rollers. Further, when the center roller and the outer ring rotate in a predetermined direction at a speed ratio corresponding to a speed ratio between the input shaft and the output shaft, the intermediate roller serving as the wedge roller is moved to a narrow portion of the annular space. Move toward.

In particular, in the friction roller type transmission according to the first aspect, at least the outer peripheral surface of the intermediate roller serving as the wedge roller is covered with a material having wear resistance. For this purpose, for example, at least the intermediate roller serving as the wedge roller is made of ceramic, at least the outer peripheral surface of the intermediate roller is nitrided, or at least the outer peripheral surface of the intermediate roller is treated with a phosphoric acid film.

Further, in the friction roller type transmission according to the present invention, at least one of the outer peripheral surface of the intermediate roller serving as the wedge roller and the inner peripheral surface of the outer ring has a DLC. (Diamond Like Carbon).

Further, in the friction roller type transmission according to the present invention, at least one of the intermediate roller serving as the wedge roller and the outer ring has a Cr (chromium) content of 8%. X which is a value within the range of ２０20% by weight
It is composed of steel which is% by weight. At the same time, a nitride layer in which the concentration of N (nitrogen) is not less than 3% by weight and not more than (0.26x + 4.42)% by weight is provided on the peripheral surface of the member that comes into contact with the counterpart peripheral surface; The hardness of the peripheral surface is Hv
1100 or more.

[0026]

The operation of the friction roller type transmission of the present invention configured as described above, when transmitting the rotational force while shifting between the input shaft and the output shaft, is performed by the conventional friction roller type transmission described above. It is the same as the case of the machine. In particular, in the case of the friction roller type transmission according to the present invention, the rotation speed of the output shaft is higher than the speed corresponding to the rotation speed of the input shaft, and the outer peripheral surface of each intermediate roller and the inner peripheral surface of the outer ring are different. Even in the case of rubbing, wear of the outer peripheral surfaces of these intermediate rollers can be suppressed.

[0027]

1 to 3 show an example of an embodiment of the present invention. The friction roller type transmission of the present invention also
As in the case of the above-described conventional structure, a fixed housing including a bottomed cylindrical body 4a made of steel or an aluminum alloy and a steel lid 5a closing a base end opening of the body 4a. 3a. The inner half (the left half in FIG. 1) of the center roller 25a is inserted into the housing 3a through a through hole 6a formed substantially in the center of the lid 5a. In addition, this through-hole 6a extends from the center of the lid 5a.
It is provided at a position slightly off. The outer end (the right end in FIG. 1) of the center roller 25a is an input shaft.
An end of a drive shaft 26 of an electric motor (not shown) is connected.

In the case of the illustrated example, the center roller 25
a is provided so as to be freely rotatable by the drive shaft 26 and slightly displaceable in the radial direction (diameter direction of the center roller 25a itself). For this reason, in the case of this example, the inner diameter of the through hole 6a is made larger than the outer diameter of the center roller 25a, and the center roller 25a
It can be displaced in the radial direction inside a.
An engagement groove 27 is formed in the base end face (right end face in FIG. 1) of the center roller 25a in the diametric direction, and is engaged with the tip end face (left end face in FIG. 1) of the drive shaft 26. Collision part 28
Are formed over the diameter direction. The engaging projection 28 and the engaging groove 27 are loosely engaged. For this reason, the width of the engaging groove 27 is slightly larger than the width of the engaging projection 28. Therefore, the center roller 25a and the drive shaft 26 are connected to each other so as to freely transmit a rotational force and to be relatively displaceable in the radial direction. The structure for coupling the center roller 25a and the drive shaft 26 so as to freely transmit the rotational force and to be relatively displaceable in the radial direction is not limited to the one shown in the drawing, but may be a loose spline. Or loose key engagement.

Further, the front end surface of the center roller 25a (FIG. 1)
A steel ball 29 is press-fitted and fixed at the center of the left end surface of the connecting plate 30, and the steel ball 29 is abutted against the center of one surface (the right surface in FIG. 1) of a connecting plate 30 described later to constitute a pivot bearing. The pivot bearing is provided for positioning the center roller 25a in the axial direction while allowing the center roller 25a to rotate freely. In the case of this example, there is a gap between the outer peripheral surface of the center roller 25a and the inner peripheral surface of the through hole 6a. Therefore, in order to prevent foreign matter from entering the housing 3a through such a gap,
A sealing material is provided between the casing of the electric motor (not shown) and the lid 5a. Alternatively, a seal ring such as an O-ring that is elastically deformable may be provided between the outer peripheral surface of the center roller 25a and the inner peripheral surface of the through hole 6a to close the gap itself.

Further, three support shafts 8, 8a are provided inside the housing 3a and around the center roller 25a.
Are arranged in parallel with the center roller 25a. That is, one end (the right end in FIG. 1) of each of the support shafts 8, 8a is supported by the lid 5a, and the other end (FIG. 1).
(The left end) is supported by the connecting plate 30. The connecting plate 30 is formed in a disk shape, not in a ring shape like the connecting ring 9 having the conventional structure shown in FIG. The reason for this is to constitute the pivot bearing.

In the case of this embodiment, the three support shafts 8,
2a, the two support shafts 8, 8 located on the upper center and the lower left side in FIG. 2 are press-fitted and fixed at both ends thereof into fitting holes 31, 31 formed in the lid 5a and the connecting plate 30. ing. Therefore, these two support shafts 8, 8 are not displaced in the circumferential direction or the diametric direction in the housing 3a.
On the other hand, the remaining one support shaft 8a located on the lower right side in FIG. 2 has both ends slightly displaced with respect to the lid 5a and the connecting plate 30 in the circumferential direction and the diametrical direction of the housing 3a. It is freely supported. For this reason, a part of the lid 5a and a part of the connecting plate 30, which is aligned with both ends of the support shaft 8a, has a support hole 32 having a width and a length larger than the outer diameter of the support shaft 8a. The support shaft 8a is loosely engaged with each of the support holes 32.

A wedge roller 1 which is an intermediate roller is provided around an intermediate portion of each of the support shafts 8 and 8a.
0 and the guide rollers 11a and 11b are rotatably supported by bearings 18 which are radial needle bearings. In particular, in the case of the friction roller type transmission of the present invention, the wedge roller 10 and the guide roller 11a,
At least the outer peripheral surface of 11b is covered with a wear-resistant material.

For this purpose, for example, the wedge roller 10
The guide rollers 11a and 11b are made of ceramic such as silicon nitride. Alternatively, when these wedge rollers 10 and guide rollers 11a and 11b are made of bearing steel such as SUJ2 or carburized steel, these wedge rollers 10
In addition, at least the outer peripheral surfaces of the guide rollers 11a and 11b are subjected to a nitriding treatment or a phosphoric acid film treatment. Incidentally, such a nitriding treatment or a phosphoric acid film treatment is carried out by the wedge roller 1 described above.
However, since it is troublesome to apply only to the outer peripheral surfaces of the guide rollers 11a and 11b, these wedge rollers 1 are actually used.
0 and the entire surface of the guide rollers 11a and 11b.
In any case, the outer peripheral surfaces of the wedge roller 10 and the guide rollers 11a and 11b which are in rolling contact or sliding contact with the inner peripheral surface of the outer ring 13a described later are hard surfaces having wear resistance.

The connecting plate 30 is formed on the inner surface of the lid 5a (the wedge roller 10 and the guide roller 11a,
11b, on the space side surface, which is a part of the left side surface of FIG. 1), the wedge roller 10 and the guide roller 11a,
The projections 12 are protruded from the position 11b and are fixed to the lid 5a by connection bolts 33. Further, both ends of the wedge roller 10 and the guide rollers 11a and 11b in the axial direction are
0 and the lid 5a are provided with thrust needle bearings 34, 34, respectively, so that the rollers 10, 11a,
The rotation of 11b is performed smoothly.

A cylindrical outer ring 13b is provided in a portion surrounding the wedge roller 10 and the guide rollers 11a and 11b inside the housing 3a.
Is defined as a second cylindrical surface 35. The second cylindrical surface 35 and the third cylindrical surfaces 36, 36, which are the outer peripheral surfaces of the wedge roller 10 and the guide rollers 11a, 11b, can freely contact each other. Also, the outer ring 13
The output shaft 16b is connected to b through a flange portion 37. The output shaft 16b is inserted into the inside of a support cylinder 38 formed at the center of the main body 4a constituting the housing 3a, and protrudes out of the housing 3a. In the illustrated example, the output shaft 16b is rotatably supported inside the support cylindrical portion 38 by a pair of ball bearings 39a and 39b, and the distal end opening of the support cylindrical portion 38 and the output shaft 16b are connected to each other. The space between the inner peripheral surface of the intermediate part and the intermediate part is closed by a seal ring 40.

In the case of this embodiment, the outer race 13b is provided inside the housing 3a so as to be freely displaceable in the rotation and radial directions. That is, in the case of this example, the flange portion 37 having an outward flange shape is formed at the base end portion (the right end portion in FIG. 1) of the output shaft 16b. And
The projecting pieces 41, 41 formed on the outer peripheral edge of the flange portion 37 and the notches 42, 42 formed on one axial edge (the left edge in FIG. 1) of the outer ring 13b are slightly shifted in the radial direction. It is displaceably engaged. Also, each of the protruding pieces 4
The retaining ring 44 is retained in a retaining groove 43 formed in the inner peripheral surface of the end of the outer ring 13b while the first and 41 are inserted into the inner portions (right portions in FIG. 1) of the notches 42, 42. Thus, the protruding pieces 41, 41 do not fall out of the notches 42, 42. Therefore, the outer ring 13b and the output shaft 16b are connected to each other so as to freely transmit a rotational force and to be slightly displaceable relative to the radial direction.

The third cylindrical surfaces 36, 36, which are the outer peripheral surfaces of the wedge rollers 10 and the guide rollers 11a, 11b, are first cylindrical surfaces provided on the outer peripheral surface of the center roller 25a, respectively. 45 and the second cylindrical surface 35 provided on the inner peripheral surface of the outer ring 13b. The center of the center roller 25a and the centers of the output shaft 16b and the outer ring 13b are eccentric to each other. That is, as described above, the through hole 6a through which the center roller 25a is inserted
Is provided at a position slightly deviated from the center of the housing 3a, whereas the support cylinder 38 through which the output shaft 16b is inserted is provided at the center of the housing 3a. The output shaft 16b and the outer ring 13b rotatably supported inside the support cylinder 38 are concentric with each other. Therefore, the center roller 25a, the outer ring 13b, and the output shaft 16b are eccentric with respect to each other by a shift amount δ (see FIG. 1) of the through hole 6a from the center of the housing 3a. The wedge roller 10 exists between the first cylindrical surface 45 provided on the outer peripheral surface of the center roller 25a and the second cylindrical surface 35 provided on the outer ring 13b.
And the width dimension of the annular space 20a provided with the guide rollers 11a and 11b corresponds to the eccentric amount of δ,
It is uneven in the circumferential direction.

As described above, the width dimension of the annular space 20a is made unequal in the circumferential direction, so that the wedge roller 1
0 and the outer diameters of the guide rollers 11a and 11b are different. That is, the diameters of the wedge roller 10 and the guide roller 11a located on the side where the center roller 25a is eccentric (the lower side in FIG. 2) with respect to the outer ring 13b are made equal to each other and relatively small. On the other hand, the diameter of the guide roller 11b located on the opposite side (upper side in FIG. 2) of the center roller 25a to the outer ring 13b is larger than the diameter of the wedge roller 10 and the guide roller 11a. . The three cylindrical surfaces 36, 3 which are the outer peripheral surfaces of the three wedge rollers 10 and the guide rollers 11a, 11b, which are intermediate rollers, respectively.
6 is in contact with the first and second cylindrical surfaces 45 and 35.

The above-mentioned 2 is an intermediate roller.
Of the guide rollers 11a, 11b and one wedge roller 10, the support shafts 8, 8 supporting both guide rollers 11a, 11b are connected to the housing 3a as described above.
It is fixed inside. On the other hand, the wedge roller 10
Is supported in the housing 3a as described above, and freely supports a slight displacement in the circumferential direction and the diametrical direction. Therefore, the wedge roller 10 can also be slightly displaced in the circumferential direction and the diametric direction in the housing 3a. The support shaft 8a supporting the wedge roller 10 is rotated by the support shaft 8a by an elastic material such as a compression coil spring 47 mounted on the lid 5a and the cylinder hole 46 of the connecting plate 30. The wedge roller 10 freely supported is connected to the annular space 2.
It is elastically pressed so as to move toward the narrow portion of 0a.

In the illustrated example, the compression coil spring 47,
47, each tip (the lower left end in FIG. 2;
Pressing pins 49, 49, each of which has an outward flange-shaped flange portion 48 at the lower end of the pressing pins 49, 49.
Thereby, both ends of the support shaft 8a are pressed in the same direction. Of the openings at both ends of the cylinder holes 46, 46, the openings on the opposite side to the support holes 32, 32 are closed by screw covers 50. Each of the compression coil springs 47, 47
Provided between the screw lid 50 or the inner surface of the end of the cylinder hole 46 and the flange portion 48, the pressing pins 49, 49
The elasticity in the above direction is given.

In the case of the friction roller type transmission of the present invention constructed as described above, the rotation of the center roller 25a connected to the drive shaft 26 is caused by the rotation of the first cylinder which is the outer peripheral surface of the center roller 25a. Each inner diameter side contact portion 21 which is a contact portion between the surface 45 and the third cylindrical surfaces 36, 36 which are the outer peripheral surfaces of the wedge roller 10 and the guide rollers 11a, 11b.
The wedge roller 10 and the guide rollers 11a, 11b are transmitted through the a, 21b. Further, the rotation of the wedge roller 10 and the guide rollers 11a, 11b is a contact portion between each of the third cylindrical surfaces 36, 36 and the second cylindrical surface 35 provided on the inner peripheral surface of the outer ring 13b. , The outer ring 13b via the outer diameter side contact portions 22a, 22b.
It is transmitted to. Then, the output shaft 16b connected to the outer ring 13b rotates in a direction opposite to the direction of the center roller 25a.

When the center roller 25a rotates clockwise in FIG. 2 in order to rotate the output shaft 16b by the drive shaft 26, the wedge roller 10 applies the force applied from the center roller 25a and the compression coil springs. 47, 4
7, the first and second cylindrical surfaces 45, 35
In the annular space 20a existing between the annular spaces 20a, the annular space 20a moves toward a narrow portion (the lower central portion in FIG. 2). As a result, the third cylindrical surface 36, which is the outer peripheral surface of the wedge roller 10, strongly presses the first cylindrical surface 45 and the second cylindrical surface 35. Then, the inner diameter side contact portion 21b which is a contact portion between the third cylindrical surface 36 of the wedge roller 10 and the first cylindrical surface 45, and the third cylindrical surface 36 of the wedge roller 10 and Outer diameter side contact portion 22b which is a contact portion with second cylindrical surface 35
Contact pressure increases.

An inner diameter side of the wedge roller 10;
When the contact pressure between the outer diameter side contact portions 21b and 22b increases,
At least one of the center roller 25a and the outer ring 13b is engaged with the engagement groove 27 and the engagement protrusion 28, or the protrusions 41, 41 and the notches 4 are provided.
Due to the engagement with 2, 42, they are slightly displaced in their respective diametrical directions. As a result, the contact portions between the third cylindrical surfaces 36, 36, which are the outer peripheral surfaces of the guide rollers 11a, 11b, which are the remaining two intermediate rollers, and the first cylindrical surface 45, which is the outer peripheral surface of the center roller 25a. And the two inner diameter side contact portions 21a, 21a, and these guide rollers 11a,
The two outer diameter side contact portions 22a, 22a which are the contact portions between the third cylindrical surfaces 36, 36 which are the outer peripheral surfaces of the outer ring 11b and the second cylindrical surface 35 which is the inner peripheral surface of the outer ring 13b. The contact pressure increases. Then, the outer ring 13b and the output shaft 16b
Rotates counterclockwise in FIG.

The force for moving the wedge roller 10 in the annular space 20a toward the narrow portion of the annular space 20a depends on the magnitude of the torque transmitted from the center roller 25a to the outer ring 13b. Will change accordingly. That is, as the driving torque of the center roller 25a increases, the wedge roller 10
The force for moving toward the narrow part of the width becomes large. Then, as this force increases, the contact pressure of the inner and outer diameter contact portions 21a, 21b, 22a, 22b increases. Conversely, when the driving torque is small, the inner and outer contact portions 21a, 21a
The contact pressure of b, 22a, 22b is small. For this reason, each of the inner diameter side and outer diameter side contact portions 21a, 21b, 22a, 22
The contact pressure b can be set to an appropriate value according to the magnitude of the torque to be transmitted between the drive shaft 26 and the output shaft 16b, and the transmission efficiency of the friction roller type transmission can be increased. In this state, the clutch mechanism is turned on.

On the other hand, when the outer ring 13b rotates in the counterclockwise direction in FIG. 2 while the drive shaft 26 is stopped, the wedge roller 10 is pressed by the force applied from the outer ring 13b. Against the elasticity of the coil springs 47, 47, the annular space 20a
It moves toward the wide part (the right central part in FIG. 2) of a. As a result, the third cylindrical surface 36, which is the outer peripheral surface of the wedge roller 10, does not press the first cylindrical surface 45 and the second cylindrical surface 35. The wedge roller 10 and the inner diameter side contact portions 21a, 21b, which are the contact portions between the third cylindrical surfaces 36, 36 of the guide rollers 11a, 11b and the first cylindrical surface 45, and Wedge roller 10 and guide rollers 11
The outer diameter side contact portions 22a, 22a, which are the contact portions between the third cylindrical surfaces 36, 36 and the second cylindrical surface 35 relating to a, 11b.
The contact pressure of 2b is reduced or lost. As a result, the rotation of the outer ring 13b is not transmitted to the drive shaft 26. In this state, the clutch mechanism is turned off.

As described above, when the outer wheel 13b rotates counterclockwise in FIG. 2 with the drive shaft 26 stopped and the outer wheel 13b rotates with the clutch mechanism turned off, the above-mentioned overrun occurs. As described in the section of the problem to be solved by the invention, the third cylindrical surfaces 36, 36 which are the outer peripheral surfaces of the wedge roller 10 and the respective guide rollers 11a, 11b, and the inner peripheral surface of the outer ring 13b. The second cylindrical surface 35 rubs. In the case of the friction roller type transmission of the present invention, each of the third cylindrical surfaces 36, 36
Since the third cylindrical surfaces 36 and 36 and the second cylindrical surface 3
5, each of these third cylindrical surfaces 3
Wear of 6, 36 can be suppressed.

The second cylindrical surface 35 is uniformly rubbed over its entire circumference with the mating surfaces (third cylindrical surfaces 36, 36), so that the wear does not partly progress remarkably. However, regarding the PV value of the outer diameter side contact portions 22a and 22b,
It becomes larger as in the case of the third cylindrical surfaces 36, 36 described above. Therefore, preferably, the second cylindrical surface 35 is also subjected to a nitriding treatment or a phosphoric acid film treatment.

Further, in the case of the friction roller type transmission shown in the figure, the outer diameters and mounting positions of the guide rollers 11a and 11b are slightly shifted, the constituent members are elastically deformed, and the outer ring 13b is Even in the case of thermal expansion, the third cylindrical surface 3 which is the outer peripheral surface of each of the guide rollers 11a and 11b
The contact surface pressures of the contact portions between the first and second cylindrical surfaces 45, which are the outer peripheral surface of the center roller 25a and the inner peripheral surface of the outer ring 13b, are designed as designed. Can be regulated. That is, when the outer diameter or the mounting position of each of the guide rollers 11a and 11b is shifted, the wedge roller 1
The center roller 25a and the outer ring 13b are displaced in the radial direction as 0 is displaced to a portion where the width of the annular space 20a is narrow. Then, the guide roller 11
a, 11b and the third cylindrical surfaces 36, 36, which are the outer peripheral surfaces of the wedge roller 10, the first cylindrical surface 45, which is the outer peripheral surface of the center roller 25a, and the outer ring 1
The contact surface pressure of the contact portion with the second cylindrical surface 35, which is the inner peripheral surface of 3b, is set as designed.

Therefore, high transmission efficiency can be obtained even when the outer diameter or the mounting position is slightly shifted or the constituent members are elastically deformed. In the case of such a structure in which the outer ring 13b has a centering property, not only the wedge roller 10 but also the outer peripheral surfaces of the guide rollers 11a and 11b can rub against the inner peripheral surface of the outer ring 13b during overrun. There is.
Therefore, in the case of the illustrated example, these guide rollers 11
It is necessary to cover the outer peripheral surfaces of all the intermediate rollers including a and 11b with a wear-resistant material. On the other hand, when the present invention is embodied in a structure in which the outer race 13 does not have centering properties as shown in the above-described conventional example of FIGS. 7 and 8, the outer peripheral surface is covered with a material having wear resistance. The intermediate roller may be only a wedge roller. The present invention can also be applied to a friction roller type transmission in which a pair of intermediate rollers serving as wedge rollers are provided and transmission of rotational force in both directions is free (no clutch mechanism is provided).

As described in claim 7, at least one of the outer peripheral surface of the wedge roller 10 and the inner peripheral surface of the outer ring 13b has a DLC (Diamond Like CW).
arbon), the wedge roller 10
Of the outer peripheral surface can be prevented. DLC is composed mainly of carbon and has SP ³ bonds (covalent bonds based on SP ³ hybrid orbitals) as in the case where carbon atoms constitute diamond, but partially forms graphite. It also has an SP ² bond (a covalent bond based on SP ² hybrid orbitals) and a bond with a hydrogen atom as in the case of the above, and has an amorphous structure as a whole. DL like this
The C film is formed by decomposing a hydrocarbon gas such as benzene (C ₆ H ₆ ) in a plasma and depositing it on a desired surface.
The wedge roller 10 is formed by vapor deposition such as VD or CVD (chemical vapor deposition) such as optical CVD, or PVD (physical vapor deposition) such as ionization vapor deposition or ion beam deposition. It is formed on the outer peripheral surface of the intermediate roller or the inner peripheral surface of the outer ring 13b.

The DLC film as described above has an extremely smooth surface, a low coefficient of friction, excellent abrasion resistance, adhesion resistance,
Has low aggression. Therefore, when a DLC film is formed on the outer peripheral surface of the wedge roller 10, wear of the outer peripheral surface can be prevented, and the inner peripheral surface of the outer ring 13b has a DL.
Even when the C film is formed, wear of the outer peripheral surface of the wedge roller 10 can be prevented. Of course, it is preferable to form the DLC film on the outer peripheral surface of the wedge roller 10 and the guide rollers 11a and 11b and on the inner peripheral surface of the outer ring 13b if there is no problem in cost. Also, DL
Regarding the C film, when the outer ring 13b is formed on the outer peripheral surface of the intermediate roller by a structure in which the outer ring 13b has a centering property, the outer peripheral surface of all the intermediate rollers including the guide rollers 11a and 11b is Form a DLC film.

When the DLC film is formed only on one of the inner peripheral surface and the outer peripheral surface, the DLC film is determined in consideration of the following points. From the viewpoint that the work of forming the DLC film is easily performed, the outer peripheral surface of the wedge roller 10 (preferably, the guide roller
1a and 11b). The film forming operation by CVD or PVD can be performed more easily on the outer peripheral surface than on the inner peripheral surface. From the viewpoint of ensuring the durability of the DLC film, it is preferable to form the DLC film on the inner peripheral surface of the outer ring 13b. When the surface pressure of the contact portion between the outer peripheral surface of the wedge roller 10 and each of the guide rollers 11a and 11b and the mating surface is taken into consideration, the outer diameter side contact that is the contact portion with the inner peripheral surface of the outer ring 13b is considered. The surface pressure of the portions 22a and 22b is changed to the inner diameter side contact portion 21 which is the contact portion with the outer peripheral surface of the center roller 25a.
a, 21b are lower than the surface pressure. The reason for this is that the contact area of the outer diameter side contact portions 22a and 22b is large in the contact state between the concave surface and the convex surface, whereas the contact condition of the inner diameter side contact portions 21a,
This is because the contact area of 21b is small in the contact state of the convex surfaces. Therefore, the DLC is provided on the inner peripheral surface of the outer ring 13b.
If a film is formed, the surface pressure acting on the DLC film may be low, and the durability of the DLC film can be secured. Conversely, when the DLC film is formed on the outer peripheral surface of the wedge roller 10 and each of the guide rollers 11a and 11b, the strength needs to be higher than that formed on the inner peripheral surface of the outer ring 13b. There is.

In any case, when a DLC film is formed, its surface is heated to about 200 ° C. Therefore,
Consideration must be given to prevent the base material from being annealed and the surface hardness from being lowered by the work of forming the DLC film. Therefore, the member that forms the DLC film on the surface is
Even if it is made of SUS material such as SUS440C or made of bearing steel, use a material of high temperature tempering (high temperature temper) specification.

Further, as described in claim 8, at least one of the wedge roller 10 and the outer ring 13b is provided with a Cr (chromium) content of 8 to 20% by weight.
And x weight%, which is a value within the range of
(Nitrogen) concentration of 3% by weight or more (0.26x + 4.
42) The wear of the outer peripheral surface of the wedge roller 10 can also be prevented by providing a nitrided layer of not more than weight% and making the peripheral surface have a hardness of Hv 1100 or more. In this case,
A steel member containing a large amount of Cr (wedge roller 10 or outer ring 13b, or guide rollers 11a, 11
Since the surface of b) is directly modified, the wedge roller 10 can be realized at a lower cost as compared with the case where the wedge roller 10 is made of ceramic. Further, the nitrided layer exhibits an intermediate property between general steel and ceramics, and does not peel off unlike a plated layer. As a result, compared to a case where general steel materials are brought into contact with each other, excellent wear resistance and seizure resistance can be exhibited, and the durability of the wedge roller 10 can be improved.

The surface hardness of the nitrided layer is set to Hv1100 or more in order to ensure sufficient wear resistance. For this reason, the content of Cr (x weight %) Is 8% by weight or more. Cr content is 8
If the content is less than 10% by weight, sufficient chromium nitride does not precipitate in the nitrided layer, and it is difficult to stably secure a surface hardness of Hv 1100 or more. However, the upper limit of the Cr content is 2
0% by weight. When Cr is contained in an amount exceeding 20% by weight, it is wasteful in terms of securing the required surface hardness, not only increasing the cost, but also forming a brittle δ ferrite layer and easily damaging the nitride layer. .

Further, the content of N contained in the nitrided layer is not less than 3% by weight and not more than (0.26x + 4.42)% by weight. If the content of N is less than 3% by weight, it is difficult to ensure a stable surface hardness of Hv 1100 or more without sufficient chromium nitride being precipitated in the nitrided layer. On the other hand, when N is contained in excess of (0.26x + 4.42)% by weight, the α-Fe of the matrix decreases, remarkably embrittlement proceeds, and the durability is secured such that the impact resistance is reduced. Becomes difficult.

Further, regarding the content of C (carbon),
The upper limit is set in relation to the content of Specifically, assuming that the content of C is y weight%, the value of y is y ≦ (1.41−) in relation to the above-described value x (weight%) of the Cr content.
0.05x). C content is (1.4
If it exceeds 1-0.05x), the major axis becomes 10 μm in the solidification process.
In addition, a huge eutectic carbide exceeding m is generated, which causes troubles in working, and also makes it difficult to obtain a target accuracy by finishing. Therefore, the content of C is not particularly restricted from the viewpoint of wear resistance, but from the viewpoint of processing,
It is preferable to suppress the content of C to (1.41-0.05x) wt% or less.

Next, a description will be given of an experiment conducted to determine the influence of the concentration of N in the nitrided layer and the surface hardness on the wear amount during sliding friction. The experiment was performed using a ball disk tester 51 as shown in FIG. The test by the ball disc tester 51 was performed on the ball 5 as a sample.
2 is pressed against the upper surface of the rotating disk 53 with a predetermined load for a predetermined time to wear the sliding contact portion, and it is determined whether the wear resistance is good or not based on the wear amount. The predetermined load is 1.37N
(140 gf) and the predetermined time was 300 seconds. or,
The sliding speed was 0.2 m / s (rotation speed = 100 min ⁻¹ , running track diameter = 40 mm). The rotating disk 53 is made of SUJ2 which is a high carbon chromium bearing steel and has a surface hardness of Hv7.
30. In addition, the sliding part was not lubricated. The amount of wear was determined by taking out the ball 52 after the elapse of the predetermined time, measuring the diameter D of the worn portion (FIG. 5), and calculating the volume of the worn portion from the measured value.

FIG. 6 shows the results of an experiment conducted under such conditions. As is apparent from FIG. 6, the concentration of N in the nitride layer is 3% by weight or more, and the hardness of the surface is Hv11.
If it is not less than 00, the wear of the member on which the nitride layer is formed can be sufficiently suppressed. In addition, among the points shown in FIG. 6, only the circles with the N concentration of 3% by weight or more have the surface hardness of Hv11.
00. The symbols □ and Δ indicate that the concentration of N is 4% by weight, but the surface hardness is Hv700 and Hv900, respectively.
In the case of both of these samples, the amount of wear increased. From this, even if the concentration of N is 3% by weight or more, the surface hardness is
It can be seen that when the Hv is less than 1100, sufficient abrasion resistance cannot be obtained. Further, in the case of the present invention in which the concentration of N in the nitrided layer is 3% by weight or more and the surface hardness is Hv1100, not only the wear of the ball 52 is suppressed but also the rotating disk 53 was also significantly suppressed. This means that the member according to the present invention in which the nitrided layer is formed on the surface can also suppress the wear of the mating member and improve the durability of the mating member.

[0060]

The friction roller type transmission of the present invention is constructed and operates as described above. Therefore, even when the intermediate roller serving as the guide roller and the wedge roller rubs against the mating surface, the friction roller type transmission has the same structure. Significant wear can be prevented from occurring. For this reason, sufficient durability can be ensured even under conditions of high-speed operation, as in the case of an auxiliary device for an engine, and this can contribute to the practical use of an auxiliary device driving device incorporating a friction roller type transmission.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating an example of an embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is an enlarged sectional view taken along line BB of FIG. 2;

FIG. 4 is a side view of a ball disk tester used in an experiment for confirming the effect of the invention according to claim 8;

FIG. 5 is a perspective view showing a worn portion of a ball after an experiment.

FIG. 6 is a diagram showing experimental results.

FIG. 7 is a sectional view showing an example of a conventional structure.

FIG. 8 is a cross-sectional view taken along the line CC of FIG.

FIG. 9 is a schematic cross-sectional view showing a state in which an overrun test is performed for checking wear of the outer peripheral surface of the intermediate roller.

FIG. 10 is a perspective view of an intermediate roller taken out after an overrun test.

FIG. 11 is a schematic cross-sectional view taken along the line DD of FIG. 9;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Electric motor 2 Rotating shaft 3, 3a Housing 4, 4a Main body 5, 5a Lid 6, 6a Through hole 7 Bearing 8, 8a Support shaft 9 Connecting ring 10 Wedge roller 11a, 11b Guide roller 12 Projection 13, 13, 13b Outer ring 14 Cylindrical part 15 Disk part 16, 16a, 16b Output shaft 17 Second through hole 18 Bearing 19 Pinion 20, 20a Annular space 21, 21a, 21b Inner diameter side contact part 22, 22a, 22b Outer diameter side contact Part 23 Bearing 24 Spring 25, 25a Center roller 26 Drive shaft 27 Engagement groove 28 Engagement protrusion 29 Steel ball 30 Connection plate 31 Fitting hole 32 Support hole 33 Connection bolt 34 Thrust needle bearing 35 Second cylindrical surface 36 Third cylindrical surface 37 Flange 38 Supporting cylinder 39a, 39b Ball bearing 40 Sealing 41 Protrusion 42 Notch 43 Locking groove 4 snap ring 45 first cylindrical surface 46 the cylinder bore 47 compression coil spring 48 the flange portion 49 presses the pin 50 screw cap 51 ball disc 52 ball 53 rotating disc

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Hiroyuki Ito 1-50-50 Kugenuma Shinmei, Fujisawa City, Kanagawa Prefecture Nippon Seiko Co., Ltd. (72) Inventor Tsuyoshi Saito 1-5-50 Kugenuma Shinmei, Fujisawa City, Kanagawa Prefecture Nippon Seiko Co., Ltd. (72) Inventor Susumu Tanaka 1-5-50 Kugenuma Shinmei, Fujisawa-shi, Kanagawa F-term (reference) 3J051 AA01 BA03 BB08 BC02 BC03 BD01 BE03 BE04 EC03 EC08 ED03 FA02 FA06 FA08 5H607 AA00 BB01 CC01 CC03 DD19 EE29 EE36 KK10

Claims (8)

[Claims] An input shaft, a center roller provided substantially concentrically with the input shaft at an end of the input shaft and having an outer peripheral surface as a first cylindrical surface, and an inner peripheral surface as a second roller. An outer ring provided around the center roller as a cylindrical surface so as to freely rotate relative to the center roller, an output shaft substantially concentric with the outer ring and having one end coupled to the outer ring; A plurality of support shafts arranged in parallel with the center roller in an annular space between the surface and the second cylindrical surface, and rotatably supported by each of the support shafts; A plurality of intermediate rollers having three cylindrical surfaces, the center of the center roller and the center of the output shaft and the outer ring are eccentric to make the width of the annular space unequal in the circumferential direction, At least one intermediate roller among the plurality of intermediate rollers; Roller is supported at least in the circumferential direction of the annular space so as to be freely displaceable and serves as a wedge roller, the remaining intermediate rollers serve as guide rollers, and the center roller and the outer ring move in a predetermined direction with the input shaft and the output shaft. When rotating at a speed ratio corresponding to the speed ratio between, in the friction roller type transmission to move the intermediate roller serving as the wedge roller toward the narrow portion of the annular space, at least the wedge roller and A friction roller type transmission characterized in that at least the outer peripheral surface of the intermediate roller is covered with a material having wear resistance. 2. The friction roller type transmission according to claim 1, wherein at least an intermediate roller serving as a wedge roller is made of ceramic. 3. The friction roller type transmission according to claim 1, wherein at least an outer peripheral surface of an intermediate roller serving as a wedge roller is subjected to nitriding treatment. 4. The friction roller transmission according to claim 1, wherein at least an outer peripheral surface of an intermediate roller serving as a wedge roller is treated with a phosphoric acid film. 5. The friction roller type transmission according to claim 1, wherein an inner peripheral surface of the outer ring is subjected to a nitriding treatment. 6. The friction roller type transmission according to claim 1, wherein an inner peripheral surface of the outer ring is treated with a phosphoric acid film. 7. An input shaft, a center roller provided substantially concentrically with the input shaft at an end of the input shaft and having an outer peripheral surface as a first cylindrical surface, and an inner peripheral surface as a second roller. An outer ring provided around the center roller as a cylindrical surface so as to freely rotate relative to the center roller, an output shaft substantially concentric with the outer ring and having one end coupled to the outer ring; A plurality of support shafts arranged in parallel with the center roller in an annular space between the surface and the second cylindrical surface, and rotatably supported by each of the support shafts; A plurality of intermediate rollers having three cylindrical surfaces, the center of the center roller and the center of the output shaft and the outer ring are eccentric to make the width of the annular space unequal in the circumferential direction, At least one intermediate roller among the plurality of intermediate rollers; Roller is supported at least in the circumferential direction of the annular space so as to be freely displaceable and serves as a wedge roller, the remaining intermediate rollers serve as guide rollers, and the center roller and the outer ring move in a predetermined direction with the input shaft and the output shaft. In a friction roller type transmission that moves the intermediate roller serving as the wedge roller toward a narrow portion of the annular space when rotating at a speed ratio corresponding to the speed ratio between the wedge rollers, the wedge roller serves as the wedge roller. At least one of the outer peripheral surface of the intermediate roller and the inner peripheral surface of the outer ring has a D
A friction roller type transmission characterized by forming an LC film. 8. An input shaft, a center roller provided substantially concentrically with the input shaft at an end of the input shaft and having an outer peripheral surface as a first cylindrical surface, and an inner peripheral surface as a second roller. An outer ring provided around the center roller as a cylindrical surface so as to freely rotate relative to the center roller, an output shaft substantially concentric with the outer ring and having one end coupled to the outer ring; A plurality of support shafts arranged in parallel with the center roller in an annular space between the surface and the second cylindrical surface, and rotatably supported by each of the support shafts; A plurality of intermediate rollers having three cylindrical surfaces, the center of the center roller and the center of the output shaft and the outer ring are eccentric to make the width of the annular space unequal in the circumferential direction, At least one intermediate roller among the plurality of intermediate rollers; Roller is supported at least in the circumferential direction of the annular space so as to be freely displaceable and serves as a wedge roller, the remaining intermediate rollers serve as guide rollers, and the center roller and the outer ring move in a predetermined direction with the input shaft and the output shaft. In a friction roller type transmission that moves the intermediate roller serving as the wedge roller toward a narrow portion of the annular space when rotating at a speed ratio corresponding to the speed ratio between the wedge rollers, the wedge roller serves as the wedge roller. At least one of the intermediate roller and the outer ring is made of a material having a Cr content of 8 to 2
The steel is made of x weight% which is a value within the range of 0 weight% and the peripheral surface of the member which comes into contact with the mating peripheral surface has a N concentration of 3 weight% or more (0.26x + 4 .
42) A friction roller type transmission having a nitrided layer of not more than weight% and having a hardness of Hv1100 or more on the peripheral surface.