JP2002039303A - Traction drive and method for grooving rolling element for power transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the rate of metallic contact so as to enhance the traction property of a traction drive by keeping thin the thickness of an oil film between both rolling elements. SOLUTION: The traction drive includes a metallic input side rolling element 3 secured to an input shaft 2, and a metallic output side rolling element 5 fixed to an output shaft 4 and to which motive power from the input side rolling element 3 is transmitted via oil filled between the output side rolling element and the input side rolling element 3. Of the input side rolling element 3 and the output side rolling element 4, at least one rolling element 3 has a circumferential three-dimensional fine groove 6 provided on the outer peripheral surface 3a thereof, with the depth of the groove bottom 6a of the three-dimensional fine groove 6 varying along the circumferential direction.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a traction drive device for a continuously variable transmission capable of steplessly controlling a speed ratio and a method for forming grooves in a rolling element for power transmission.

[0002]

2. Description of the Related Art Conventionally, as the traction drive device described above, for example, there is one shown in FIG.

As shown in FIG. 11, a traction drive device 101 includes a metal input-side rolling element 103 fixed to an input shaft 102 and an input-side rolling element 103 fixed to an output shaft 104. A metal output-side rolling element 105 to which power from the input-side rolling element 103 is transmitted via the filled oil is provided. On the outer peripheral surface 103a of the input-side rolling element 103, as shown in FIG. Many fine depressions 1
13, or by providing a fine groove 107 having a constant depth along the circumferential direction as shown in FIG. 13, so as to keep the oil film thickness between the two rolling elements 103 and 105 thin. ing.

When forming a large number of fine depressions 106 and fine grooves 107 on the outer peripheral surface 103a of the input-side rolling element 103, the heat-treated rolling element 103 is processed into a predetermined shape with a grinding wheel, In the case of the small depression 106, a shot peening process for injecting abrasive grains to the outer peripheral surface 103 a is performed.
Turning is performed on the 3a by using a carbide tool or a ceramic tool, and in any case, the outer peripheral surface 103a on which the fine recesses 106 and the fine grooves 107 are formed is subjected to grinding and polishing again. Excessive bulges are removed.

[0005]

However, in the above-described conventional traction drive device 101, a large number of fine depressions 1 are formed on the outer peripheral surface 103a of the input-side rolling element 103.
When 06 is provided, although oil can be held between the two rolling elements 103 and 105, it is difficult to keep the oil film thickness infinitely thin, and in addition to the limitation of improvement in traction properties, In the manufacturing stage, the optimal depression 106
In order to obtain, there is a problem that abrasive grains used for shot peening must be fine and uniform, which makes production and management of abrasive grains difficult.

On the other hand, the outer peripheral surface 103 of the input side rolling element 103
In the case where the fine grooves 107 are provided in a, since the oil is simultaneously discharged while holding the oil in the fine grooves 107, it is possible to keep the oil film thickness thin to some extent.
There is a possibility that metal contact may occur between the input rolling elements 103 and 105 at the stage of forming a groove.
By selecting the processing conditions such as the rotation speed of the cutting tool, the feed speed of the cutting tool, and the depth of cut, it is theoretically possible to obtain the optimal groove shape relatively easily, but in practice, the tip of the cutting tool is severely worn. Since the life is short, there is a problem that mass production processing is difficult, and solving these problems has been a conventional problem.

[0007]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional problems, and the invention according to claims 1 to 6 can keep the oil film thickness between both rolling elements small,
It is an object of the present invention to provide a traction drive device capable of suppressing the occurrence of metal contact and consequently improving traction.
It is an object of the present invention to provide a method of forming a groove in a rolling element for power transmission, which can extend the life of a turning tool and improve productivity.

[0008]

According to a first aspect of the present invention, there is provided a traction drive device comprising: a metal input-side rolling element fixed to an input shaft; and an input-side rolling element fixed to an output shaft. In a traction drive device provided with a metal output-side rolling element to which power from an input-side rolling element is transmitted via oil filled in, at least one of an input-side rolling element and an output-side rolling element The outer peripheral surface of the moving body is provided with a three-dimensional fine groove along the circumferential direction capable of keeping the oil film thickness between the two rolling bodies thin and suppressing metal contact. Means to solve the problem.

According to a second aspect of the present invention, there is provided a traction drive device comprising: a metal input-side rolling element fixed to an input shaft; and an oil filled between an input-side rolling element fixed to an output shaft. In a traction drive device including a metal output-side rolling element to which power from an input-side rolling element is transmitted through, a circle is formed on an outer peripheral surface of at least one of the input-side rolling element and the output-side rolling element. A three-dimensional fine groove is provided along the circumferential direction, and the groove bottom depth of the three-dimensional fine groove is changed along the circumferential direction. The configuration of this traction drive device is to solve the conventional problems. Means. The traction drive device according to claim 3 of the present invention has a configuration in which three-dimensional fine grooves are formed in a spiral shape on the outer peripheral surface of the rolling element. A plurality of rolling elements are formed in an annular shape on the outer peripheral surface.

The traction drive device according to claim 5 of the present invention has a configuration in which the heights of the groove bottoms of the three-dimensional micro grooves adjacent in the axial direction are shifted from each other in the circumferential direction, so that a particularly high traction property is obtained. In the traction drive device according to claim 6 of the present invention,
The groove bottom depth of the three-dimensional fine groove is set to a maximum of 10 μm.

A traction drive device according to a seventh aspect of the present invention has a configuration in which the groove width of the three-dimensional fine groove is increased or decreased in synchronization with the height of the groove bottom. In this manner, the groove width is synchronized with the height of the groove bottom. In the traction drive device increased and decreased in order to obtain particularly high traction, the traction drive device according to claim 8 of the present invention has a maximum groove width that increases and decreases in synchronization with the height of the groove bottom of the three-dimensional micro groove. 10
The thickness is set to 0 μm.

On the other hand, according to a ninth aspect of the present invention, there is provided a method for forming a groove in a power transmitting rolling element, wherein a groove bottom depth is formed on an outer peripheral surface of a rolling element of a traction drive device having the power transmitting rolling element in a circumferential direction. In forming a three-dimensional fine groove that changes along the axis, a turning tool having a pointed end and a neck part having a constant width and a rotating rolling element are relatively close to and separated from each other in the radial direction of the rolling element. The method of forming a groove in a rolling element for power transmission is a means for solving the conventional problems.

According to a tenth aspect of the present invention, there is provided a method for forming a groove in a power transmitting rolling element, wherein a groove bottom depth is formed along a circumferential direction on an outer peripheral surface of a rolling element of a traction drive device having the power transmitting rolling element. In order to form a three-dimensional micro-groove in which the width changes and the groove width increases and decreases in synchronization with the height of the groove bottom, the turning tool is rotated with a turning tool having a pointed end and a neck having a width gradually increasing continuously from this point. The rolling elements are relatively close to and separated from each other in the radial direction of the rolling elements. The configuration of the groove forming method for the power transmitting rolling elements is a means for solving the conventional problems.

[0014]

In the traction drive device according to the first and second aspects of the present invention, the three-dimensional fine groove along the circumferential direction is formed on the outer peripheral surface of at least one of the input side rolling element and the output side rolling element. (In the traction drive device according to the second aspect, a three-dimensional fine groove is provided on the outer peripheral surface of the rolling element along the circumferential direction and the groove bottom depth is changed along the circumferential direction.) Therefore, the oil is retained between the rolling elements and the oil is appropriately drained. As a result, the oil film thickness between the rolling elements is kept thin, and in addition, the occurrence of metal contact occurs. Is suppressed, so that the traction is improved.

[0015] In the traction drive device according to claim 3 of the present invention, since the traction drive device has the above-described configuration, when forming the three-dimensional fine groove in a spiral shape on the outer peripheral surface of the rolling element, the three-dimensional fine groove having a constant depth is used. The contact area between the turning tool and the rolling element is always changed as compared with the case of forming a spiral, that is, it is possible to prevent the load from being concentrated on one point of the cutting edge of the turning tool. Therefore, the productivity is improved due to the extension of the tool life, and the traction drive device according to claim 4 of the present invention has the above-described configuration. Therefore, the three-dimensional fine grooves are formed on the outer peripheral surface of the rolling element. In forming an annular shape, a load in the axial direction is hardly applied to the turning tool, and also in this case, the productivity is significantly improved due to the extension of the tool life.

In the traction drive device according to the fifth aspect of the present invention, since the traction drive device has the above-described structure, it is possible to prevent a sudden change in the lubrication state on the outer peripheral surface of the rolling element when the rolling element rotates. As a result, stable traction performance can be obtained, and the traction drive device according to claim 6 of the present invention has the above-described configuration, so that extremely high traction performance can be obtained.

In the traction drive device according to claim 7 of the present invention, since the above-described structure is employed, the rolling element can be formed by performing relatively simple processing such as forming three-dimensional fine grooves on the outer peripheral surface of the rolling element. The outer peripheral surface becomes a pseudo cross hatch surface, so that more stable traction performance can be obtained. In the traction drive device according to claim 8 of the present invention, by adopting the above configuration,
Extremely high traction performance will be obtained.

On the other hand, in the method of machining a groove for a power transmission rolling element according to the ninth aspect of the present invention, since the above-described structure is employed, a three-dimensional fine groove having a constant depth is formed in a spiral shape. Therefore, the load can be prevented from being concentrated on one point of the cutting edge of the turning tool, and the life of the tool can be prolonged. According to the groove forming method of the rolling element for power transmission according to claim 10 of the present invention, , Because of the above configuration,
With a simple configuration, it is possible to form a three-dimensional fine groove whose groove bottom depth changes along the circumferential direction and whose groove width increases and decreases in synchronization with the height of the groove bottom.

[0019]

In the traction drive device according to claims 1 and 2 of the present invention, since the above-mentioned structure is employed, the oil film thickness between the two rolling elements can be kept as thin as possible, and the distance between the two rolling elements can be reduced. This can prevent metal contact from occurring, and as a result, a very excellent effect that traction can be improved can be achieved.

In the traction drive device according to the third aspect of the present invention, since the traction drive device is configured as described above, the same effect as that of the traction drive device according to the first and second aspects can be obtained, and in addition to the three-dimensional fine groove. When forming a spiral, it is possible to avoid concentration of the load on one point of the cutting tool edge, and therefore, it is possible to greatly improve the productivity with the extension of the life of the turning tool. In the traction drive device according to the fourth aspect of the present invention, since the traction drive device has the above-described configuration, when forming a three-dimensional fine groove in an annular shape, the groove is formed with almost no axial force applied to the turning tool. In this case as well, a very excellent effect that it is possible to realize a significant improvement in productivity with a prolonged tool life is achieved.

[0021] In the traction drive device according to claim 5 of the present invention, the lubrication state of the outer peripheral surface can be prevented from suddenly changing when the rolling element rotates, as a result. In the traction drive device according to the sixth aspect of the present invention, a very excellent effect that particularly high traction performance can be obtained is obtained. It is.

In the traction drive device according to claim 7 of the present invention, since the above configuration is adopted, the outer peripheral surface of the rolling element can be a pseudo cross hatch surface, and more stable traction performance can be obtained. In the traction drive device according to claim 8 of the present invention,
With the above-described configuration, a very excellent effect that extremely high traction performance can be obtained is brought about.

On the other hand, according to the groove forming method of the rolling element for power transmission according to claim 9 of the present invention, since the above-described configuration is adopted,
The groove bottom depth changes along the circumferential direction without complicating the structure and extending the tool life.
A tenth-dimensional fine groove can be formed,
In the method of forming a groove for a power transmission rolling element according to the above, the groove depth is varied along the circumferential direction and the groove width is increased / decreased in synchronism with the height of the groove bottom because of the above configuration. Can be formed with a simple structure.

[0024]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

FIGS. 1 to 5 show an embodiment of a traction drive device according to the present invention.

As shown in FIG. 1, the traction drive device 1 includes a metal input-side rolling element 3 fixed to an input shaft 2 and an input-side rolling element 3 fixed to an output shaft 4. A metal output-side rolling element 5 to which power from the input-side rolling element 3 is transmitted via the filled oil is provided.

In this embodiment, a three-dimensional fine groove 6 is formed in a spiral shape on the outer peripheral surface 3a of the input-side rolling element 3 along the circumferential direction, and as shown in FIG. 6
The depth of the groove bottom 6a is varied along the circumferential direction. In this embodiment, in order to obtain particularly high traction, the depth of the groove bottom 6a of the three-dimensional fine groove 6 is set to a maximum of 10 μm.
And

In the traction drive device 1, when forming the three-dimensional fine groove 6 in which the depth of the groove bottom 6a changes along the circumferential direction on the outer peripheral surface 3a of the input side rolling element 3, as shown in FIG. Thus, the turning tool 20 having the pointed end 21 and the neck 22 having a constant width continuous with the pointed end is approached to and separated from the rotated input-side rolling element 3 in the radial direction to perform the groove processing.

In this case, as shown in FIG.
0 may be attached to the table T of the turning device S, and the turning tool 20 may be moved closer to or away from the input-side rolling element 3 by the feeding operation of the table T, or as shown in FIG.
The turning tool 20 may be attached to the actuator Ac provided on the table T of the turning device S, and only the turning tool 20 may be moved closer to or away from the input-side rolling element 3 by the operation of the actuator Ac.

In the traction drive device 1, the power transmitted to the input shaft 2 is transmitted from the input rolling element 3 to the output shaft 4 via oil filled between the rolling elements 3 and 5.

At this time, the depth of the groove bottom 6a of the three-dimensional fine groove 6 spirally formed along the circumferential direction on the outer peripheral surface 3a of the input-side rolling element 3 is changed along the circumferential direction. Therefore, the three-dimensional fine groove 6 has a function of retaining oil,
The oil is also appropriately discharged, so that the oil film thickness between the two rolling elements 3 and 5 is kept small, and the occurrence of metal contact between the two rolling elements 3 and 5 is suppressed. ,
The traction is improved.

In the traction drive device 1, since the three-dimensional micro-grooves 6 of the input-side rolling element 3 are spirally formed along the circumferential direction, the outer peripheral surface 3a of the input-side rolling element 3 has When forming the three-dimensional fine groove 6, compared to a case where a three-dimensional fine groove having a constant depth is formed spirally,
The contact area between the turning tool 20 and the input-side rolling element 3 is constantly changed, so that it is possible to prevent the load from being concentrated on one point of the cutting edge of the turning tool 20, and to produce the turning tool 20 with a longer life. That is, the performance is improved.

Further, the traction drive device 1
In the groove machining method of the input-side rolling element 3 (the rolling element for power transmission) in
And a turning tool 20 having a neck portion 22 having a constant width which is continuous with the turning tool 20 is moved in a radial direction of the input-side rolling element 3 by table feeding or operation of an actuator to perform groove machining. It is possible to form the three-dimensional fine groove 6 in which the depth of the groove bottom 6a changes along the circumferential direction without increasing the life of the groove and without complicating the structure.

FIG. 6 shows another embodiment of the traction drive device according to the present invention.

As shown in FIG. 6, in this embodiment, three-dimensional grooves 16 spirally formed in the outer peripheral surface 13a of the input-side rolling element 13 along the circumferential direction are adjacent to each other in the axial direction. Position 16H of the groove bottom 16a of the two-dimensional fine groove 16
And the low position 16L is displaced in the circumferential direction by approximately 周期 cycle. In the traction drive device provided with the input-side rolling element 13, the input-side rolling element 13 rotates when the input-side rolling element 13 rotates. A sudden change in the lubrication state on the outer peripheral surface 13a of the moving body 13 can be prevented from occurring, and as a result, stable traction performance can be obtained.

FIG. 7 shows still another embodiment of the traction drive device according to the present invention.

As shown in FIG. 7, in this embodiment, in the three-dimensional micro-groove 16 spirally formed in the outer circumferential surface 13a of the input-side rolling element 13 along the circumferential direction, the groove width W is changed to the groove bottom. The groove width W which increases and decreases in synchronization with the height of the bottom of the three-dimensional fine groove 16 is set to 100 μm at the maximum in order to obtain particularly high traction.

In the traction drive device provided with the input-side rolling elements 13, as shown in FIG. 8, a turning tool 30 having a point 31 and a neck 32 having a width gradually increasing continuously from the point 31 is rotated. The outer peripheral surface 13a of the input-side rolling element 13 can be formed as a pseudo cross-hatch surface only by performing relatively simple processing such as making the input-side rolling element 13 approach and separate in the radial direction. ,
Further stable traction performance can be obtained.

FIG. 9 shows still another embodiment of the traction drive device according to the present invention.

As shown in FIG. 9, in this embodiment, an annular three-dimensional fine groove 16 is formed on the outer peripheral surface 13a of the input-side rolling element 13.
In the traction drive device provided with the input-side rolling elements 13, a plurality of annular three-dimensional micro-grooves 16 </ b> A are formed on the outer peripheral surface 13 a of the input-side rolling elements 13. Since almost no load is applied in the axial direction, in this embodiment as well, the productivity is greatly improved with the extension of the tool life.

FIG. 10 shows another embodiment of the method of forming a groove in the rolling element for power transmission according to the present invention. As shown in FIG. 10, in this embodiment, the power roller of the toroidal continuously variable transmission is used. The case where a three-dimensional micro groove 56 is formed in the power transmission rolling element 53 is shown.

When forming a three-dimensional fine groove 56 whose groove bottom depth changes along the circumferential direction on the outer peripheral surface 53 a of the power roller 53, first, the power roller 53 is pulled in and the end surface of the main shaft 61 is moved by the jig 60. The turning tool 20 attached to the actuator Ac provided on the table T of the turning device S is fixed to the power roller 53 together with the actuator Ac while giving a constant cut to the power roller 53 in the radial direction. Along the axis and in the radial direction.

At this time, the turning tool 20 is moved separately from the power roller 53 by the operation of the actuator Ac.
Swinging in the radial direction of the turning tool 20 changes the cutting depth of the turning tool 20 continuously.
The three-dimensional fine groove 56 whose groove bottom depth changes along the circumferential direction is formed in 3a.

That is, in the method of forming a groove in the rolling element for power transmission according to the present invention, it is possible to impart excellent traction to members requiring large power transmission, such as the power roller 53, and at the same time, At the time of manufacturing, the wear of the tool is suppressed to a small level, so that the productivity is greatly improved.

The detailed configuration of the traction drive device and the groove forming method of the rolling element for power transmission according to the present invention is as follows.
The present invention is not limited to the above embodiment.

[Brief description of the drawings]

FIG. 1 is a front explanatory view (a) and a side explanatory view schematically showing an embodiment of a traction drive device according to the present invention.
(b).

FIG. 2 is an explanatory sectional view taken along a line AA in FIG. 1;

FIG. 3 is an operation explanatory view showing a situation in which a three-dimensional fine groove is formed by a turning device on an outer peripheral surface of an input-side rolling element of the traction drive device in FIG. 1;

FIG. 4 is an operation explanatory view showing a situation in which a three-dimensional fine groove is formed on the outer peripheral surface of the input-side rolling element of the traction drive device in FIG. 1 by another turning device.

FIG. 5 is an operation explanatory view showing a turning tool for forming a dimensional fine groove on an outer peripheral surface of an input-side rolling element of the traction drive device in FIG. 1;

FIG. 6 is an explanatory sectional view schematically showing an input-side rolling element according to another embodiment of the traction drive device according to the present invention.

FIG. 7 is an explanatory front view schematically showing an input-side rolling element according to still another embodiment of the traction drive device according to the present invention.

8 is an operation explanatory view showing a turning tool for forming a dimensional fine groove on an outer peripheral surface of an input-side rolling element of the traction drive device in FIG. 7;

FIG. 9 is an explanatory front view schematically showing an input-side rolling element according to still another embodiment of the traction drive device according to the present invention.

FIG. 10 is an operation explanatory view showing a situation in which a three-dimensional fine groove is formed on an outer peripheral surface of a power roller by a turning device using another embodiment of the method for forming a groove of a power transmission rolling element according to the present invention.

11A and 11B are a schematic front view and a schematic side view, respectively, of a conventional traction drive device.

FIG. 12 is an explanatory cross-sectional view schematically showing an input-side rolling element employed in the traction drive device of FIG. 11;

FIG. 13 is an explanatory front view schematically showing another input-side rolling element used in the traction drive device of FIG. 11;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Traction drive device 2 Input shaft 3,13 Input side rolling element 3a Outer peripheral surface 4 Output shaft 5 Output side rolling element 6,16,16A Three-dimensional micro groove 6a Groove bottom 20 Turning tool 53 Power roller (rolling element for power transmission) W groove width

 ────────────────────────────────────────────────── ─── Continued from the front page (72) Inventor Minoru Ota 2 Takaracho, Kanagawa-ku, Yokohama-shi, Kanagawa Prefecture F-term in Nissan Motor Co., Ltd. 3C045 DA02 DA08 3J051 AA01 BA10 BB02 BD01 BE03 EC02 EC06 ED08 FA02 FA06

Claims (10)

[Claims] Power transmitted from an input-side rolling element is transmitted through an oil filled between an input-side rolling element made of metal fixed to an input shaft and an input-side rolling element fixed to an output shaft. In the traction drive device having a metal output-side rolling element, the outer peripheral surface of at least one of the input-side rolling element and the output-side rolling element has a thin oil film between the two rolling elements. A traction drive device having three-dimensional fine grooves along a circumferential direction capable of suppressing metal contact. Power from the input-side rolling element is transmitted through oil filled between the input-side rolling element made of metal fixed to the input shaft and the input-side rolling element fixed to the output shaft. In the traction drive device having a metal output-side rolling element to be provided, at least one of the input-side rolling element and the output-side rolling element is provided with a three-dimensional fine groove along the circumferential direction on the outer peripheral surface of the rolling element; A traction drive device wherein the groove bottom depth of the three-dimensional fine groove is changed along the circumferential direction. 3. The traction drive device according to claim 1, wherein the three-dimensional fine groove is spirally formed on the outer peripheral surface of the rolling element. 4. The traction drive device according to claim 1, wherein a plurality of three-dimensional fine grooves are annularly formed on the outer peripheral surface of the rolling element. 5. The traction drive device according to claim 3, wherein the heights of the groove bottoms of the three-dimensional micro grooves adjacent in the axial direction are mutually shifted in the circumferential direction. 6. The groove bottom depth of the three-dimensional fine groove is up to 10 μm.
The traction drive device according to any one of claims 2 to 5, wherein 7. The traction drive device according to claim 2, wherein the width of the three-dimensional fine groove is increased or decreased in synchronization with the height of the groove bottom. 8. The traction drive device according to claim 2, wherein a groove width that increases and decreases in synchronization with the height of the groove bottom of the three-dimensional fine groove is at most 100 μm. 9. A three-dimensional micro-groove having a groove bottom depth varying along a circumferential direction is formed on an outer peripheral surface of a rolling element of a traction drive device having a power transmitting rolling element. A method for forming a groove in a rolling element for power transmission, characterized in that a turning tool having a neck portion having a constant width and a rotating rolling element are successively approached and separated from each other in a radial direction of the rolling element. 10. The groove bottom depth changes along the circumferential direction on the outer peripheral surface of the rolling element of the traction drive device having the power transmitting rolling element, and the groove width increases and decreases in synchronization with the height of the groove bottom. In forming a three-dimensional fine groove, a turning tool having a pointed part and a neck part having a width gradually increasing continuously from the point is relatively approached to and separated from a rotated rolling element in a radial direction of the rolling element. A groove forming method for a rolling element for power transmission, characterized in that: