Method for producing pulley for belttype continuously variable …

30 Апр 2014 | Author: | Комментарии к записи Method for producing pulley for belttype continuously variable … отключены
Lexus ES Electric Cars

BACKGROUND OF THE INVENTION

1. Field of the

The present invention relates to a for producing a pulley for a belt-type variable transmission of an automobile or the (a belt-type continuously variable pulley).

2. Description of the Related Art

In the of pulleys for belt-type continuously transmissions (hereinafter referred to as CVTs), for example, Japanese Patent Publication No. 2007-262470 is as a conventional technology specifying a texture of a sliding surface on a belt is slid.

In Japanese Patent Publication No. 2007-262470, a is composed of a chrome steel or a molybdenum steel according to JIS The sliding surface of the pulley a hardened layer harder the inside, and has a surface texture a surface roughness Rz of 1.4 to 6.3 μm and a ratio (a ratio of the reduced peak Rpk to the reduced valley depth Rvk to JIS B0671) of less than

The pulley having the above texture is excellent in abrasion and is useful for the CVT.

In view of the abrasion resistance of the sliding it is important to increase an oil holding (an ability to hold a lubricant of the sliding surface. This is also in Japanese Laid-Open Publication No. 2007-262470.

In this publication, the surface texture of the surface is defined based on the roughness Rz, the reduced peak Rpk, and the reduced valley Rvk, and it is particularly preferred the reduced valley depth Rvk is than the reduced peak Rpk.

However, even the reduced valley depth is than the reduced peak a lubricant oil cannot be easily into a valley with a shape. On the contrary, when the width is excessively larger the peak width, the lubricant oil in the may readily leak therefrom. it may be difficult to hold the lubricant oil in the so that the pulley cannot have a desired oil holding


SUMMARY OF THE INVENTION

In view of the problems, an object of the present is to provide a method for producing a for a belt-type continuously variable capable of producing a belt-type CVT having improved oil holding and improved abrasion resistance by a process at lower cost excellent reproducibility.

[1] According to a aspect of the present invention, a for producing a pulley for a belt-type variable transmission, a contact of the pulley to be brought into with an element being by machining, is characterized in that the comprises a grinding step of the shape of the contact surface, a step of roughening the contact to form grooves therein, and a surface lapping step of the contact surface having the with a lapping film to oil grooves for holding a lubricant and the contact surface has such a roughness that the maximum roughness Rz is 4 μm or less, the mean RSm of the roughness profile elements is 30 to 60 μm, the Rsk of the roughness profile is −2.7 to (no unit), the reduced peak Rpk is 0.09 μm or less, and the reduced depth Rvk is 0.4 to 1.3 μm.

With the above method, oil property of the belt-type CVT pulley can be and thus the belt-type CVT pulley improved abrasion resistance can be with excellent reproducibility.

[2] to a second aspect of the present a method for producing a pulley for a continuously variable transmission, a surface of the pulley to be brought contact with an element formed by machining, is characterized in the method comprises a grooving of simultaneously performing a grinding for forming the shape of the contact and a process for roughening the contact to form grooves therein, and a surface lapping step of the contact surface having the with a lapping film to oil grooves for holding a lubricant and the contact surface has such a roughness that the maximum roughness Rz is 4 μm or less, the mean RSm of the roughness profile elements is 30 to 60 μm, the Rsk of the roughness profile is −2.7 to (no unit), the reduced peak Rpk is 0.09 μm or less, and the reduced depth Rvk is 0.4 to 1.3 μm.

With the above oil holding property of a belt-type CVT can be improved, and thus the belt-type CVT having improved abrasion can be produced with excellent Furthermore, the pulley can be obtained by a process at lower cost.

As above, in the belt-type continuously transmission pulley production of the present invention, the belt-type CVT having improved oil holding and improved abrasion resistance can be by a simplified process at lower with excellent reproducibility.

The and other objects features and of the present invention will more apparent from the description when taken in with the accompanying drawings in a preferred embodiment of the present is shown by way of illustrative example.

BRIEF DESCRIPTION OF THE DRAWINGS

1 is a fragmentary cross-sectional view a metal belt and a belt-type CVT produced by a production method to an embodiment of the present invention;

2 is a fragmentary perspective view showing the metal belt;

3 is a process chart of a first for producing the belt-type CVT pulley;

4 is a chart for explaining a mean RSm of roughness profile elements;

5A and 5B are charts for explaining a skewness Rsk of a profile;

FIG. 6 is a chart for a reduced peak height Rpk and a valley depth Rvk; and

7 is a process chart of a second for producing the belt-type CVT pulley.

OF THE PREFERRED EMBODIMENTS

An embodiment of the CVT pulley production method of the invention will be described with reference to FIGS. 1 to 7. It be noted that, in this a numeric range of “A to B” includes the numeric values A and B as the lower and upper limit values,

As shown in FIG. 1, a belt-type CVT (hereinafter referred to simply as the 10 ) produced by a belt-type CVT pulley method according to this (hereinafter referred to as the production is used with a metal 12 wound thereon. As shown in 2, in the metal belt 12 . a large of metal elements 16 are supported by a of right and left metal aggregates 14 . and each of the metal aggregates 14 is provided by stacking a of metal rings 18 . Each of the elements 16 has at the horizontal ends a of contact surfaces 16 a that can be into contact with wall surfaces (contact 10 a ) of the pulley 10 (see FIG.

1).

As in FIG. 3, a first method of the method according to this contains a grinding step S 1 of the shape of the contact surface 10 a in the 10 . a grooving step S 2 of roughening the surface 10 a to form grooves and a contact surface lapping S 3 of lapping the contact surface 10 a the grooves with a lapping to form oil grooves for holding a oil.

After the step S 3 . the roughness of the contact surface 10 a is that the maximum height Rz is 4 μm or less, the mean length RSm of the profile elements is 30 to 60 μm, the skewness Rsk of the profile is −2.7 to −0.6 (no the reduced peak height Rpk is μm or less, and the reduced valley Rvk is 0.4 to 1.3 μm.

The above parameters of the surface will be described below reference to FIGS. 4 to 6.

A stylus is on the contact surface 10 a . and the trajectory of the tip center is measured to obtain a profile. The traced profile is to a total profile (quantized of the traced profile). The total is low-pass filtered using a value λs to obtain a primary without stylus distortions or

Furthermore, the primary profile is filtered using a cutoff λc to obtain a roughness profile.

The height roughness Rz is the maximum in the roughness profile, which is the sum of the peak height (the value) and the largest valley (the absolute value) the reference length Lr according to JIS 2001 (ISO 4288:1996).

As in FIG. 4, the mean length RSm of the profile elements is the average of the of the roughness profile elements peak-valley combinations) contained the reference length Lr, and is obtained the following arithmetic expression

RSm = 1 m ⁢ ∑ i = 1 m ⁢ Wi ( 1 )

roughness profile elements an excessively large pitch, and the oil readily leaks from the surface 10 a . resulting in oil holding deterioration. On the other hand, the mean length RSm is less 30 μm, the depth of the valley is disadvantageously for holding the lubricant oil.

The Rsk of the roughness profile is the mean value of Z(x) non-dimensionalized by the of the root-mean-square height Rq within the length, and is obtained using the arithmetic expression (2).

Rsk = 1 Rq 3 ⁡ [ 1 Lr ⁢ ∫ 0 Lr ⁢ Z 3 ⁡ ( x ) ⁢ ⁢ ⅆ x ] ( 2 )

As in FIGS. 5A and 5B, a unit length has a area Aa and a valley area Ab. In

5A, the peak area Aa is smaller the valley area Ab, the probability distribution peak is shifted to the from the center, and the skewness Rsk is a value (0). On the other in FIG. 5B, the peak area Aa is than the valley area Ab, the density distribution peak is to the left from the center, and the Rsk is a negative value (0). the probability density distribution is a distribution, the skewness Rsk is 0. Thus, the Rsk represents the symmetry of the peak and the and is a parameter useful for confirming the oil holding ability.

Lexus IS Electric Cars

In general, when the contact 10 a is ground, it exhibits a negative Rsk. The lubricant oil holding can be improved by reducing the negative When the contact surface 10 a has a skewness Rsk, the peak has a top shape and the valley has a large whereby the lubricant oil readily from the valley, resulting in oil property deterioration.

Though the 10 may have a skewness Rsk of less −2.7 (an absolute value of the is larger than 2.7), the lower limit of the skewness Rsk is from the viewpoint of the oil holding

In this embodiment, a smoothed profile of the contact surface 10 a is from the primary profile FIG. 6). The smoothed roughness is used to obtain parameters reduced peak height Rpk and the valley depth Rvk) for evaluation of a plateau structure

The smoothed roughness profile may be by the following filtering treatments. the above primary profile is with a phase compensation to calculate a first mean a DC portion is removed from the mean line to calculate a mean line, the second line is treated with a compensation filter to calculate a mean line, and the third line is subtracted from the profile to obtain the smoothed profile.

As shown in FIG. 6, in the smoothed roughness profile, the widths are added while a line is moved from the end toward the lower end within the length Ln to make a bearing curve. A 40%-length equivalent line is drawn with to the bearing area curve. The point between the equivalent line and the 0% vertical line is as the upper level of the core, and the point between the equivalent line and the 100% vertical is defined as the lower level of the

The evaluation length Ln is generally times as large as the reference Lr.

The area of a triangle equivalent to the surrounded by the top of the bearing area and the upper level of the core is as an equivalent triangle area A 1 . and the of the equivalent triangle is defined as the peak height Rpk. On the hand, the area of a triangle to the area surrounded by the 100% line, the lower level of the and the bearing area curve is as an equivalent triangle area A 2 . and the of the equivalent triangle is defined as the valley depth Rvk.

In the first method, for example, a grinding process is performed a cutting tool in step S 1 . a lapping process may be performed a lapping agent (a material a machining fluid and abrasive mixed in the machining fluid) careful attention to the affect on the valley depth Rvk in step S 2 . and a finish lapping process may be using a lapping film in S 3 .

In the first method, since the height roughness Rz is 4 μm or less, the peak height Rpk is 0.09 μm or the reduced valley depth Rvk is 0.4 to 1.3 μm, and the mean length RSm of the roughness elements is 30 to 60 μm, and the skewness Rsk of the roughness is −2.7 to −0.6 (no unit), oil property of the belt-type CVT pulley 10 can be and thus the belt-type CVT pulley 10 improved abrasion resistance can be with excellent reproducibility.

As in FIG. 7, a second method of the method according to this contains a grinding-grooving step S 101 of a grinding process for forming the of the contact surface 10 a in the pulley 10 roughening the contact surface 10 a to grooves therein, and a contact lapping step S 102 of lapping the surface 10 a having the grooves a lapping film to form oil for holding a lubricant oil.

in the second method, after S 102 . the surface roughness of the contact 10 a is such that the maximum roughness Rz is 4 μm or less, the mean RSm of the roughness profile elements is 30 to 60 μm, the Rsk of the roughness profile is −2.7 to (no unit), the reduced peak Rpk is 0.09 μm or less, and the reduced depth Rvk is 0.4 to 1.3 μm.

In the second method, for a grooving process and a grinding may be simultaneously performed (a grinding-grooving may be performed) using a surface while adjusting the surface in step S 101 . and then a finish process may be performed using a film in step S 102 .

In the second since the maximum height Rz is 4 μm or less, the reduced peak Rpk is 0.09 μm or less, the reduced depth Rvk is 0.4 to 1.3 μm, and further the mean RSm of the roughness profile elements is 30 to 60 μm, and the Rsk of the roughness profile is −2.7 to (no unit) in the same manner as the first method, oil holding of the belt-type CVT pulley 10 can be improved and the belt-type CVT pulley 10 with abrasion resistance can be produced excellent reproducibility.

Particularly, in the second method, the grinding process for forming the of the contact surface 10 a of the pulley 10 is while the contact surface 10 a is to form the grooves therein in the step S 101 . the pulley 10 can be obtained by processes at lower cost.

In Examples 1 to 6 and Comparative Examples 1 to 10, a surface 10 a of each pulley 10 was and an abrasion loss of each surface 10 a was measured and evaluated.

and Carbon Concentration]

The materials and the carbon concentrations of Examples 1 to 6 and Examples 1 to 10 are shown in Table 1.

Processing Method]

The surface of each contact surface 10 a was as follows (see Table 1).

in the surface processing of Comparative 1 to 3, 9 and 10, a grinding process was performed a cutting tool.

In the surface of Examples 1 to 3 and Comparative Examples 4 to 8, a grinding process was performed a cutting tool, a rough process was performed using a agent (a material containing a fluid and abrasive grains in the machining fluid) with attention to the affect on the reduced depth, and then a finish process was performed using a film.

In the surface processing of 4 to 6, a grooving process and a grinding were simultaneously performed (a process was performed) using a grinder while adjusting the texture, and then a finish process was performed using a film.

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