JP5056591B2 - Toroidal continuously variable transmission - Google Patents

Description

  The present invention relates to an improvement in a toroidal continuously variable transmission that is used, for example, as an automatic transmission for automobiles or as a transmission for adjusting the operating speed of various industrial machines such as pumps. Specifically, in order to improve the traction coefficient of the rolling contact portion between the circumferential surface of each power roller and one axial side surface of each disk, the circumferential surface of each power roller and one axial side surface of each disk With a structure in which a large number of concave grooves (fine grooves) are provided on at least one of these surfaces, both ensuring durability and ensuring traction coefficient are achieved.

  The use of a toroidal type continuously variable transmission as an automobile transmission is partly implemented and well known. 8 and 9 show the basic configuration of a (half) toroidal continuously variable transmission currently being implemented. This toroidal-type continuously variable transmission is called a double-cavity type, and a pair of input-side discs 1 and 1 with respect to the input rotary shaft 2 are each a toroidal curved surface (concave arc-shaped concave surface) and patented. The input side inner side surfaces 3 and 3 corresponding to one side surface in the axial direction described in the claims are opposed to each other, and are supported concentrically and freely in synchronization with each other.

  An output cylinder 5 having an output gear 4 fixed to the outer peripheral surface of the intermediate portion is supported around the intermediate portion of the input rotary shaft 2 so as to freely rotate with respect to the input rotary shaft 2. Further, output side disks 6 and 6 are supported at both ends of the output cylinder 5 so as to be rotatable in synchronization with the output cylinder 5 by spline engagement. In this state, each of the output side inner surfaces 7 and 7 of the output side disks 6 and 6, each of which is a toroidal curved surface and corresponding to one axial side surface recited in the claims, is the both input side inner side surfaces. 3 and 3 are opposed.

  Further, two power rollers 8 and 8 each having a spherical convex surface on each of the peripheral surfaces (cavities) between the input side and output side inner side surfaces 3 and 7 around the input rotation shaft 2 are provided. It is arranged. The power rollers 8 and 8 are respectively connected to the inner surfaces of the trunnions 9 and 9 via support shafts 10 and 10 whose base half and tip half are eccentric and a plurality of rolling bearings. 10 is supported in such a manner that it can be rotated about the front half of the front half and a small amount of swinging about the base half of each of the support shafts 10 and 10. Each trunnion 9, 9 is provided with a tilting shaft 11 provided concentrically with each other for each trunnion 9, 9 at both ends in the length direction (front and back direction in FIG. 8, vertical direction in FIG. 9). , 11 can be swung freely.

  The operation of swinging (tilting) the trunnions 9 and 9 is performed by displacing the trunnions 9 and 9 in the axial directions of the tilt shafts 11 and 11 by hydraulic actuators 12 and 12. That is, at the time of shifting, the trunnions 9 and 9 are displaced in the axial direction of the tilt shafts 11 and 11 by supplying and discharging pressure oil to and from the actuators 12 and 12. As a result, the direction of the force acting in the tangential direction of the rolling contact portion (traction portion) between the peripheral surface of each of the power rollers 8 and 8 and each of the input side and output side inner surfaces 3 and 7 changes (side slip). Therefore, the trunnions 9 and 9 are oscillated and displaced about the tilt shafts 11 and 11, respectively.

  During operation of the toroidal-type continuously variable transmission as described above, one input side disk 1 (left side in FIG. 8) is rotationally driven by a drive shaft 13 via a loading cam type pressing device 14. As a result, the pair of input-side disks 1 and 1 supported at both ends of the input rotation shaft 2 rotate synchronously while being pressed in a direction approaching each other. Then, this rotation is transmitted to the output side disks 6 and 6 through the power rollers 8 and 8 and is taken out from the output gear 4.

  When the ratio of the rotational speed between the input rotary shaft 2 and the output gear 4 is changed, and when deceleration is first performed between the input rotary shaft 2 and the output gear 4, the trunnions 9, 9 are shown in FIG. The power rollers 8 and 8 are swung to the positions shown in FIG. 3 so that the peripheral surfaces of the input-side discs 1 and 1 near the center of the input-side discs 1 and 3 and the output-side discs 6 and 6 It is made to contact | abut to the outer peripheral side part of the output side inner surfaces 7 and 7, respectively. On the contrary, when the speed is increased, the trunnions 9 and 9 are swung in the direction opposite to that shown in FIG. 8, and the peripheral surfaces of the power rollers 8 and 8 are input to the input disks 1 and 2. It is made to contact | abut to the outer periphery side part of the side inner side surfaces 3 and 3 and the center side part of the output side inner side surfaces 7 and 7 of the said output side disks 6 and 6, respectively. If the swing angles of the trunnions 9 and 9 are set in the middle, an intermediate gear ratio can be obtained between the input rotary shaft 2 and the output gear 4.

  During operation of the toroidal type continuously variable transmission as described above, the rolling contact between the input side and output side inner surfaces 3 and 7 of the input and output disks 1 and 6 and the peripheral surfaces of the power rollers 8 and 8 is performed. In the section (traction section), power is transmitted through the traction oil. When power is transmitted in this way, the value of the friction coefficient (traction coefficient) of the traction oil is determined. Therefore, in order to transmit a large torque at the rolling contact portion, it is necessary to apply a large pressing force to the rolling contact portion. However, when such a large pressing force is applied, the durability of the input side and output side disks 1 and 6 and the power rollers 8 and 8 may be reduced. Further, in order to secure the strength of each of the disks 1 and 6 and the power rollers 8 and 8, the members 1, 6, and 8 may be increased in size, which is not preferable from the viewpoint of reducing the size of the apparatus. .

  On the other hand, in order to prevent the above-described inconveniences, for example, Patent Documents 1 to 4 disclose that the depth on the one side surface in the axial direction of each disk 1 or 6 or the peripheral surface (traction surface) of each power roller 8 is described. Describes a technique for forming a large number of concave grooves of about 0.1 μm to 8 μm over the entire surface. By adopting such a technique, it is considered that the traction coefficient of the rolling contact portion can be improved, and a large torque can be transmitted with a small pressing force as compared with a structure in which such a concave groove is not formed. However, it has been found by experiments of the present inventors that the degree (improvement allowance) for improving the traction coefficient is reduced or sufficient durability (proof stress) cannot be secured depending on the shape of each of the concave grooves. . In addition, the processing method (formation method) for each of the grooves also ensures the traction coefficient and the durability according to various properties (surface property standards) representing the surface roughness of the surface on which the grooves are formed. It was also found that there are items that can be evaluated and items that cannot be evaluated.

  In Patent Document 5, a triangular concavo-convex formed of a flat portion and a depression is formed on the traction surface of a disk and a roller constituting a full toroidal continuously variable transmission, and the surface roughness is regulated. The technology to do is described. Specifically, -5 ≦ Rsk (skewness) ≦ 0, 0.01 μm ≦ Ra (arithmetic average height) ≦ 0.12 μm. However, it is considered that even if such regulation is performed, it is not possible to sufficiently improve the traction coefficient and ensure the durability.

JP 2002-39306 A JP 2003-207909 A JP 2003-278869 A JP 2003-343675 A JP 2005-90633 A

  In view of the circumstances as described above, the present invention aims to improve the traction coefficient of the rolling contact portion between the peripheral surface of each power roller and one axial side surface of each disk, A structure in which a large number of concave grooves (fine grooves) are provided on at least one of the sides in the axial direction of the disk, and various properties related to the surface roughness of the surface on which each concave groove is formed are set in detail. In this way, a structure that can achieve both durability and traction coefficient is realized.

The toroidal type continuously variable transmission of the present invention includes at least a pair of disks and a plurality of power rollers, as in the conventional toroidal type continuously variable transmission as described above.
Each of these disks is supported concentrically and freely in relative rotation in a state in which the respective one side surfaces in the axial direction, each of which is a toroidal curved surface having an arc cross section, are opposed to each other.
Each of the power rollers is provided at a plurality of locations in the circumferential direction between the axial side surfaces of each of the disks with respect to the axial direction. Each one is in contact with one side of the direction.
The depth of at least one of the peripheral surface of each power roller and one axial side surface of each disk is, for example, 8 μm or less, more preferably 5 μm or less, and even more preferably 2.3-4. A large number of concave grooves of 0 μm are formed.

In particular, in the toroidal-type continuously variable transmission according to the present invention, the surface roughness of the surface on which each of the concave grooves is formed is measured with respect to the radial direction of the member, and Rsk (skewness) <0, Rku (kurtosis). ) <4, 0.4 μm <Rp (maximum peak height) <2.0 μm, 0.12 μm <Ra (arithmetic average height) <2.0 μm. More preferably, −1.375 <Rsk <−0.324, 1.515 <Rku <3.504, 0.589 μm <Rp (maximum peak height) <1.268 μm, 0.524 μm <Ra <1.228 μm. To regulate. These various properties (Rsk, Rku, Rp, Ra) representing the surface roughness are surface property standards defined in “JIS B0601: 2001”.
Further, when implementing such a toroidal type continuously variable transmission according to the present invention, preferably, as described in claim 2, the grooves are formed so as to cross each other. At the same time, the grooves are formed so as to form an angle with respect to the circumferential direction of the member on which the grooves are formed, when viewed from the normal direction of the surface on which the grooves are formed. In other words, an imaginary concentric circle centered on the central axis of the member on which each groove is formed, which appears on the surface (one side surface, circumferential surface) on which each groove is formed, and the groove are (Make it have an angle). The angle formed is 45 degrees or less.

  The angle formed above is preferably larger on the inner side than on the outer side in the radial direction of the member (the angle on the outer diameter side <the angle on the inner diameter side). If constituted in this way, this concave groove is a tool for forming these concave grooves (for groove processing) while rotating the members (disk, power roller) to be formed with these concave grooves at a constant speed. With this cutting tool or grindstone abutting on the work surface, the tool is displaced (oscillated or moved) at a constant speed in the radial direction (and axial direction) of the member in which each concave groove is to be formed. ). This is because the peripheral speed of the portion processed by the processing tool becomes faster as compared to the inner side in the radially outer side, and the angle with respect to the circumferential direction becomes smaller as the speed increases. However, if the angle formed exceeds 45 degrees, the displacement speed of the processing tool must be increased with respect to the rotational speed of the member that should form the concave grooves, and the work of forming the concave grooves is difficult. It becomes troublesome. Therefore, the angle formed as described above is set to 45 degrees or less from the viewpoint of ensuring the ease of forming these concave grooves.

According to the toroidal-type continuously variable transmission of the present invention configured as described above, a structure in which a large number of concave grooves are formed to improve the traction coefficient, and both ensuring the traction coefficient and ensuring durability are achieved. Can be planned.
That is, the surface roughness of the surface on which each of the concave grooves is formed is a measured value in the radial direction of the member, and Rsk (skewness) <0, Rku (kurtosis) <4, 0.4 μm <Rp (maximum peak height) <2.0 μm, 0.12 μm <Ra (arithmetic mean height) <2.0 μm Of these, Rsk (skewness) is the degree of deviation (distortion) of the roughness curve. By making this Rsk (skewness) smaller than 0 (to a negative value), the amplitude of the roughness curve is increased. It is possible to improve the traction coefficient based on the presence of each of the concave grooves by biasing in the direction (existing deep concave portions). When the Rsk (skewness) is 0 or more, the amplitude of the roughness curve is biased in the depth direction (there is a high convex portion), and metal contact may easily occur. (Durability may not be sufficient).

  The above Rku (kurtosis) is the degree of sharpness of the roughness curve. By making this Rku (kurtosis) smaller than 4, the sharpness in the height direction of the roughness curve is alleviated and rolling. It is possible to suppress metal contact at the contact portion (traction portion) and easily ensure durability. In addition, when the Rku (Cultosis) is 4 or more, the sharpness in the height direction of the roughness curve becomes excessive, metal contact is likely to occur at the rolling contact portion (traction portion), and sufficient durability can be secured. Disappear.

  The Rp (maximum peak height) is the maximum peak height of the roughness curve. By setting the Rp (maximum peak height) to 0.4 to 2.0 μm, the height of each concave groove is Therefore, the traction coefficient can be improved and the durability can be ensured based on the presence of these grooves. If the Rp (maximum peak height) is less than 0.4 μm, the grooves are too shallow, and the traction coefficient based on the presence of the grooves cannot be sufficiently improved. Further, when the Rp (maximum peak height) exceeds 2.0 μm, the grooves are excessively deep, and it is not possible to sufficiently ensure the durability of the members formed with the grooves. .

  The Ra (arithmetic average height) is an average value of the absolute values of the height of the roughness curve within the reference length, and this Ra (arithmetic average height) is 0.12 to 2.0 μm. In this way, while ensuring the necessary depth for each of the grooves, the surface of the surface (traction surface) on which the grooves are formed (the traction surface) can suppress the roughness of the portions that are removed from the grooves (smooth). In addition, the metal contact at this portion can be suppressed and the traction coefficient can be improved. When the Ra (arithmetic average height) is less than 0.12 μm, the grooves are too shallow, and the traction coefficient based on the presence of the grooves cannot be sufficiently improved. Also, when Ra (arithmetic mean height) exceeds 2.0 μm, the part removed from the above-mentioned concave grooves becomes rough, and metal contact at this part is likely to occur, and sufficient durability is ensured. become unable.

  1 and 2 show an example of an embodiment of the present invention. The feature of this example is a structure in which a large number of concave grooves 15 and 15 for improving the traction coefficient are formed. In order to achieve both of ensuring durability and ensuring the traction coefficient, each of these concave grooves 15 is provided. , 15 (the axial side surface 17 of the disk 16 and the peripheral surface 18 of the power roller 8 described later) are restricted in surface roughness. Since the structure and operation of other parts are the same as those of the conventional structure shown in FIGS. 8 and 9, the overlapping illustrations and explanations will be omitted or simplified, and the following description will focus on the characteristic parts of this example.

  In the case of this example, as shown in FIGS. 1 and 2, the axial side surface 17 of each disk 16 constituting the toroidal-type continuously variable transmission {the surface of FIG. 1 (a), FIG. 2 and FIG. 1 (b) In the upper surface, corresponding to the input side inner surface 3 and the output side inner surface 7 in FIG. The grooves 15 and 15 are formed over the entire one side surface 17 so as to cross each other. 1 and 2 (and FIGS. 3 to 5 to be described later), in order to make it easy to understand the formation state of each of the grooves 15, 15, the grooves 15, 15 are exaggerated and schematically represented by { The groove width and groove pitch P of the grooves 15, 15 are drawn larger than the actual relationship}.

  Further, in the case of this example, each of the concave grooves 15, 15 is viewed in the normal direction of the one axial side surface 17 {see the mark of the line of sight in FIG. They are formed so as to form angles α and β (see FIG. 2). In other words, the virtual concentric circle X centered on the central axis of the disk 16 that appears on the one side surface 17 in the axial direction and the concave grooves 15 and 15 form the angles α and β (the angle is changed). Have). The angles α and β formed are larger on the inner side (inner diameter side) than on the outer side in the radial direction (outer diameter side) of the disk 16.

  That is, as shown in FIG. 2 in which the disk 16 is developed, angles α and β formed by the concave grooves 15 and 15 and a virtual concentric circle X corresponding to the circumferential direction of the disk 16 are defined as outer diameters. The angle β on the inner diameter side is made larger than the angle α on the side (so that α <β). 2 is a diagram showing a concave curved surface, which is one side surface 17 of the disk 16, in a state of being developed on a plane {for example, the surface of the globe (the ground surface) is a planar world map by Mercator projection. The virtual concentric circles X are represented in parallel with each other in the horizontal direction of the page in FIG. 2 (the virtual concentric circles X correspond to the latitude lines of the world map). Then, the angles α and β formed in FIG. 2, which is such a development view, correspond to the angles α and β when viewed from the normal direction of the one side surface 17, and the angle α , Β is regulated to satisfy the relationship of α <β.

FIG. 1A shows a state of the disk 16 as viewed in the axial direction from the small diameter side. The angles α _a and β _a shown in FIG. It becomes an apparent corner when viewed in the direction. FIG. 1B shows the disk 16 viewed from the outside in the radial direction. The angles α _b and β _b shown in FIG. 1B indicate the disk 16 in the radial direction. This is the apparent corner when viewed. The angles α, α _a , α _b and the angles β, β _a , β _b are at the same position in the radial direction of the disk 16 (the normal of one side 17 and the center axis of the disk 16). Corresponds to the positions at which the angles formed with the virtual plane intersecting at right angles to θα and θβ, respectively.

  In the case of this example, the concave grooves 15, 15 can be formed as follows. That is, a processing tool (groove cutting tool such as precision machining tool or grinding tool such as super finishing grindstone) for forming the concave grooves 15 and 15 while rotating the disk 16 at a constant speed. The tool is swung at a constant speed (or moved along the processing surface) in the radial direction (and the axial direction) of the disk 16 in a state where the processing tool is in contact with the one side surface 17 which is the processing surface. . Then, by rotating or moving the processing tool at a constant speed while rotating the disk 16 at a constant speed in this way, the concave grooves 15 and 15 are formed on the one side surface 17, and the normal line of the one side surface 17. When viewed from the direction, the angle formed by the disk 16 with respect to the circumferential direction (the angle formed by the virtual concentric circle X and each of the concave grooves 15, 15) is larger in the inner diameter side than in the outer diameter side of the disk 16. is doing.

  It should be noted that the pitches P and the angles α and β formed by the concave grooves 15 and 15 are the rotational speed of the disks 16 and the axial speed and radial speed (oscillating angular speed) of the processing tool. By adjusting, the desired value can be regulated. Further, if necessary, the rotational speed of each of the disks 16 can be changed, and the displacement speed of the processing tool can be changed. However, if the machining is performed at a constant speed, it is not necessary to provide a mechanism for changing the rotation speed in the machining apparatus, so that the apparatus can be configured simply and the cost required for forming the concave grooves 15 and 15 can be reduced. I can plan. In addition, the angle formed by the above-mentioned concave grooves 15 and 15 is restricted to 45 degrees or less from the aspect of ensuring the ease of formation. The reason for this is that if the angle exceeds 45 degrees, the displacement speed of the processing tool must be increased with respect to the rotational speed of the member on which the grooves 15 and 15 are to be formed. This is because the work of forming the is troublesome. In addition, when forming each said concave groove 15 and 15 by a cutting process, if necessary, it grinds after a process and removes the fine burr | flash produced on the to-be-processed surface. The concave grooves 15, 15 can also be formed by rolling as will be described later.

  The concave grooves 15 and 15 are not limited to the path as shown in FIGS. 1 and 2, and for example, as shown in FIG. 3, the center axis (rotation axis) of the disk 16 is the center. It is also possible to form a concentric circle (or a spiral). For example, as shown in FIGS. 4 and 5, it can be formed on the peripheral surface 18 of each power roller 8. In FIG. 4, the concave grooves 15 are formed so as to form an angle with respect to the circumferential direction of the power roller 8. The angle formed is larger on the inner side than the outer side in the radial direction of the power roller 8 when viewed from the normal direction of the peripheral surface of the power roller 8. In FIG. 5, the concave grooves 15 are formed concentrically (or spirally) with the central axis (rotating shaft) of the power roller 8 as the center.

  The concave grooves 15 and 15 can be formed on the traction surfaces (one side surface 17 and the peripheral surface 18) of both the members 16 and 8 of the disk 16 and the power rollers 8. It can also be formed only on one of the members. That is, the disk 16 formed with the concave grooves 15 and 15 and the power roller 8 can be used in combination, and each disk 16 (or each power roller 8) formed with the respective concave grooves 15 and 15 Also, each power roller 8 (or disk 16) which is not formed (smooth surface) can be used in combination.

  When the concave grooves 15 and 15 are formed on the traction surfaces (one side surface 17 and the peripheral surface 18) of both the members 16 and 8, between the disks 16 (the input side disk 1 and the output side). The groove 15 formed in the power roller 8 at the rolling contact portion between the circumferential surface 18 of each power roller 8 and one axial side surface 17 of each disk 16 irrespective of the transmission ratio between the disk 6 and the disk 6. , 15 and the respective concave grooves 15, 15 formed in the respective disks 16 are opposed to each other at an angle (for example, an angle of 5 to 90 degrees). This is because the grooves 15 and 15 formed in each power roller 8 and the grooves 15 and 15 formed in each disk 16 face each other in parallel (for example, the disk 16 in FIG. 3 and the power in FIG. 5). Depending on the gear ratio, the substantial area of the rolling contact portion (the total contact area of the portions of the rolling contact portion that are out of the grooves 15, 15) may be reduced depending on the gear ratio. This is because the durability may decrease.

  In any case, in the case of this example, the surface roughness of the traction surface (one side surface 17, the peripheral surface 18) on which each of the concave grooves 15, 15 is formed (the one side surface 17 or the peripheral surface 18 is provided with each groove 15. , 15 is a measured value in the radial direction of the member (disk 16, power roller 8), and Rsk (skewness) <0, Rku (kurtosis) <4, 0.4 μm < Rp (maximum peak height) <2.0 μm, 0.12 μm <Ra (arithmetic average height) <2.0 μm. These various properties (Rsk, Rku, Rp, Ra) representing the surface roughness are surface property standards defined in “JIS B0601: 2001”. Below, the point which came to restrict | limit to the above numerical values is demonstrated.

  That is, as shown in Table 1 below, the present inventor manufactured samples 1 to 13 having different surface roughness characteristics and different groove processing methods, and the traction coefficient and life of each sample were experimentally determined. It was determined whether it was preferable. In the column of “Traction coefficient” and “Life” in Table 1, “◯” indicates that a favorable result is obtained, “×” indicates that an undesirable result is obtained, and “△” indicates that it is sufficient. Although it is not, it shows that the result of the grade which is not a problem practically was obtained, respectively. More specifically, in the column of “traction coefficient”, the improvement rate of the traction coefficient is less than 1% as compared with the structure of the conventional smooth surface (no groove), “x”, and 1 to 3%. “△”, 4% or more was “◯”. On the other hand, in the column of “life”, the case where peeling (damage) occurred at the internal origin was indicated as “◯”, and the case where peeling occurred at the surface origin was indicated as “Δ”. The conventional smooth surface structure (without grooves) that can ensure sufficient durability causes internal origin separation, whereas those that cause surface origin separation cause metal contact due to improper groove shape. This is because it can be estimated that this occurs.

The various properties of the surface roughness in Table 1 are as follows. These various properties were measured by “Form Talysurf Series 2 (S6C-PGI) (manufactured in July 2003)” manufactured by Taylor Hobson Co., Ltd. For the definition of these various properties, see “Parameter Description” of the surface shape and roughness measuring machine of Taylor Hobson Co., Ltd. and “Definition of Surface Roughness and Explanation of Parameters” of Mitutoyo Corporation's Surface Roughness Measuring Machine. Are listed. Among these various properties, “S (average distance between local peaks)”, “Ry (maximum height)”, “Sm (average distance between irregularities)” and “Rz (ten-point average roughness)” are “ This is in accordance with the standard of JIS B0601: 1994.
Ra: arithmetic average height
Rq: root mean square height
Rp: Maximum mountain height
Rv: Maximum valley depth
Rt: Maximum section height
Rt1: Maximum section height within the standard length 1
Rt2: Maximum section height 2 within the standard length
Rt3: Maximum section height 3 within the standard length
Rt4: Maximum section height 4 within the standard length
Rt5: Maximum cross-section height within the standard length 5

Rsk: Skewness
Rku: Kurtosis
Delq (△ q): root mean square slope
Lamq (λq): root mean square wavelength
S: Average distance between local peaks
Ry: Maximum height
RzDIN: Ten-point average roughness obtained from the entire evaluation length
Rpm: Average mountain height
R3y: Maximum height of the third point determined from the entire evaluation length
R3z: Three-point roughness determined from the entire evaluation length
Rk: Effective load roughness

Rpk: Initial wear height
Rvk: Oil sump depth
Mr1: Load length ratio 1
Mr2: Load length ratio 2
Sm: Average interval of unevenness (average length)
Lo: Expanded length
Dela (△ a): Arithmetic mean slope
Ra * Ry: (Arithmetic mean height) x (Maximum height)
Ra / Rz: (arithmetic average height) / (ten-point average roughness)
Rku / Rsk: (Kurtosis) / (Skness)
Rv / Rku: (Maximum valley depth) / (Cultosis)

  In samples 1 to 4, the groove processing is “super-finish”. In Samples 1 and 2, the traction surface was smoothed with a superfinishing grindstone, whereas in Samples 3 and 4, the swing speed of the superfinishing grindstone was decreased compared to Samples 1 and { By lowering the oscillation speed (amplitude speed) of the grinding wheel relative to the workpiece rotation speed from the normal level} and using a rough super-finishing grindstone as well, the concave grooves having a groove depth of about 0.5 to 1.0 μm are random (irregular) ). The “rolling” of the samples 5 and 6 is a rolling process, that is, a processed surface (one side surface 17, a peripheral surface 18) with a foam roller having a tip R of about 0.05 to 0.2 μm at a constant pressure by a spring. A concave groove was formed on this surface by pressing against the surface. In the case of such rolling processing, processing is performed not by position control but by load control, so that it can be processed by a processing machine having a normal accuracy (for example, a lathe). In addition, the “cutting” of the samples 7 to 11 is performed by performing biaxial control of a cutting tool {ceramics or CBN (diamond) tip} having a tip R of about 0.05 to 0.2 μm. A concave groove was formed in a spiral shape on the processed surface (one side surface 17, peripheral surface 18). In the case of such cutting processing, since processing is performed by position control, it is necessary to have a processing machine, workpiece fixing means, position detection, and the like that are more accurate than the above rolling processing. Further, “grinding” of the samples 12 and 13 was a grinding stone formed by a grinding process, that is, a total rotary dress, and the concave grooves were formed concentrically. Of the samples 1 to 13, the surface roughness curve (profile data) of sample 3 is shown in FIG. 6, and the surface roughness curve (profile data) of sample 5 is shown in FIG.

In addition, experiments (tests) of “traction coefficient” and “life” were performed as follows. That is, a toroidal continuously variable transmission in which adjustment of the pressing force can be controlled by a hydraulic pressing device was operated at a constant speed while applying a constant torque by a dynamo tester. As for the “traction coefficient” test, slipping occurs in the process of starting the operation with a value with a sufficient margin against the sliding force of the traction section and gradually decreasing the pressing force. Calculated and evaluated the traction coefficient at the time when synchronization loss occurred. The test conditions are as follows.
Input torque (Tin): 350 Nm
Input rotation speed (Nin): 2000min ^-1
Reduction ratio (Icvt): 0.7, 1.0, 1.5
Oil temperature (Thin): 85 ° C, 100 ° C, 120 ° C

On the other hand, regarding the “lifetime” test, an operation was performed under the following conditions while applying a pressing force with a loading cam type pressing device, and the time during which peeling occurred on the traction surface (the state of peeling) was evaluated. It should be noted that the durability is 10 to 40 hours for surface-origin separation and 70 hours or more for internal-origin separation.
Input torque (Tin): 294Nm
Input rotation speed (Nin): 4000min ^-1
Reduction ratio (Icvt): 1.938
Traction coefficient: 0.0505

From Table 1, the following can be understood. That is, Samples 1 and 2 do not improve the traction coefficient, and Samples 3 and 4 do not sufficiently improve the traction coefficient. For this reason, in view of the traction coefficient, samples 5 to 13 are preferable. Further, from the viewpoint of the life , the samples 12 and 13 are slightly shortened (a satisfactory life cannot be obtained). Then, from such results and various properties of the surface roughness of the sample corresponding thereto, the surface roughness of the traction surface (one side surface 17, the peripheral surface 18) on which each of the concave grooves 15, 15 is formed is expressed as Rsk ( It is preferable to regulate to (skewness) <0, Rku (Cultosis) <4, 0.4 μm <Rp (maximum peak height) <2.0 μm, 0.12 μm <Ra (arithmetic average height) <2.0 μm. It can be seen that it is more preferable to regulate (−1.375 <Rsk <−0.324, 1.515 <Rku <3.504, 0.589 μm <Rp <1.268 μm, 0.524 μm <Ra <1.228 μm). I understand that too). In addition, when the required lifetime is short or when the traction coefficient may be small, the range including the numerical values corresponding to the samples 12 and 13 and the samples 3 and 4 can be regulated. Also, the numerical value can be regulated in relation to the groove processing method. In this example, Rsk, Rku, Rp, and Ra are regulated among the above-described various properties representing the surface roughness. However, the above-described various properties other than these can be used as necessary. In this case as well, regulation is performed within a range of numerical values corresponding to samples 5 to 11 (samples 3 to 13 as necessary) which are preferable samples.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which exaggerates and shows an example of embodiment of this invention, (a) is an end elevation of a disk, (b) is the figure seen from the downward direction of (a). The figure which expand | deploys a disk and abbreviate | omits a part of ditch | groove and shows typically. The figure similar to FIG. 1 which shows another example of the formation state of a ditch | groove. It is a figure which exaggerates and shows a ditch | groove, (a) is an end view of a power roller, (b) is the figure seen from the downward direction of (a). The figure similar to FIG. 4 which shows another example of the formation state of a ditch | groove. The surface roughness curve of the sample 3 used for experiment. The surface roughness curve of the same sample 5. Sectional drawing which shows one example of the toroidal type continuously variable transmission used as the object of this invention. The figure equivalent to the AA cross section of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Input side disk 2 Input rotating shaft 3 Input side inner surface 4 Output gear 5 Output cylinder 6 Output side disk 7 Output side inner surface 8 Power roller 9 Trunnion 10 Support shaft 11 Tilt shaft 12 Actuator 13 Drive shaft 14 Press device 15 Concave Groove 16 Disc 17 Axial one side 18 Circumference

Claims (2)

  At least one pair of discs that are concentrically supported by each other in a state in which one side surfaces in the axial direction, each of which is a toroidal curved surface having an arc-shaped cross section, are opposed to each other and freely rotatable relative to each other, and each of these discs in the axial direction. A plurality of power rollers provided at a plurality of positions in the circumferential direction between the axial side surfaces of the disk, and each circumferential surface as a spherical convex surface is in contact with the axial one side surface of each disk; A toroidal continuously variable transmission in which a plurality of concave grooves are formed on at least one of the circumferential surface of each power roller and one axial side surface of each disk. The surface roughness of the formed surface was regulated to Rsk <0, Rku <4, 0.4 μm <Rp <2.0 μm, 0.12 μm <Ra <2.0 μm, as measured in the radial direction of the member. Toroidal stepless, featuring transmission.   Each groove is formed in a state of crossing each other, and each groove is a circumference of the member in which each groove is formed when viewed from the normal direction of the surface on which each groove is formed. The toroidal-type continuously variable transmission according to claim 1, wherein an angle is formed with respect to the direction, and the formed angle is 45 degrees or less.

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