JP2002031215A - Belt-type cvt pulley and v-belt for pulley - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the core deviation amount of a V-belt. SOLUTION: A profile curve in the section including the central axis of a pulley, of a sheave surface 1a of the belt-type CVT pulley 1 is a gentle projecting curved line having the sheave angle gradually changed. The side surface angle of the belt to be used for the pulley 1 is continuously changed from the inner peripheral side to the outer peripheral side between the angle equal to the maximum sheave angle to the angle equal to the minimum sheave angle. In the profile curve in the section including the central axis of the pulley of the sheave surface, the axial distance direction X from a point of a radius Ro to a point of a radius R of the gear ratio of 1 is X=R×tanαO+ K/(RO- Rmin)×(R-RO)2=(0<K<=0.02) in relation to the reference sheave angle αO and the minimum radius Rmin.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention
The present invention relates to a pulley for a (stepless transmission) and a V-belt for the pulley.

[0002]

2. Description of the Related Art A conventional belt type CVT pulley is disclosed in
As shown in FIG. 11 disclosed in US Pat. No. 100443, a sheave surface 1a of each of input and output pulleys 1 of a continuously variable transmission mechanism which comes into contact with a V-belt 2 is known. 12, the sheave angle α is constant regardless of the position in the radial direction. Therefore, as shown by the characteristic line A in FIG. As a result, there has been a problem that the V-belt is one-sided and excessively worn and generates loud noise.

In order to solve such a problem, the present applicant has previously disclosed in Japanese Patent Application Laid-Open No. Hei 6-307510, as shown in FIG.
The sheave angle of the sheave surface 1a in contact with the V-belt 2 is formed in two stages so that the angle α of the radially outward portion is greater than the angle β of the radially inward portion. Also disclosed is a configuration in which the side surface angle of the belt 2 is formed in two stages such that the angle α of the portion closer to the inner circumference is larger than the angle β of the portion closer to the outer circumference.

However, in the latter prior art as well, as shown in the characteristic lines B to D in FIG. 12 for the three types of combinations of the angles α and β, although the misalignment is much smaller than the former prior art, There is a limit that can reduce the misalignment,
There was a problem that the misalignment remained about 0.3 mm.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a pulley for a belt type CVT and a belt for the pulley which advantageously solve the above problems. The belt-type CVT pulley is characterized in that a contour curve of a sheave surface of the belt-type CVT pulley in a section including a center axis of the pulley is a smooth convex curve in which a sheave angle changes continuously. Is what you do.

According to this pulley, since the cross-sectional contour of the sheave surface is a convex curve, the amount of misalignment due to shifting at radially inward and outward positions with respect to the radial position of the gear ratio 1 is reduced, or Since it can be eliminated, excessive abrasion and noise due to one side contact of the V-belt can be effectively reduced.

In the pulley according to the present invention, the axial distance x from the radius R0 point of the gear ratio 1 to the radius R point of the contour curve of the cross section including the center axis of the pulley on the sheave surface is determined. , With respect to the reference sheave angle α0 and the minimum radius Rmin, x = R × tan α0 + {k / (R0−Rmin)} ×
(R-R0) ² , wherein k may be 0 <k ≦ 0.021,
According to the sheave surface of such a contour curve, when k = 0.021, the amount of misalignment due to shifting can be set to 0, and 0 <k
When <0.021, the amount of misalignment can be reduced according to the value of k as compared with the related art.

In the pulley according to the present invention, when the side surface angle is used for a V-belt having α0 equal to the reference sheave angle, k may be 0 <k ≦ 0.0018. <K ≦ 0.0018, the lateral angle α of the V-belt in the range of the speed ratio of 1 to 2.5.
The difference between 0 and the sheave angle α of the sheave surface of the pulley can be set to 0.2 ° or less, so that the torque capacity can be increased.

On the other hand, k is 0.0018 <k ≦
The V-belt for a pulley of the present invention, which is used for the belt-type CVT pulley of 0.021, has a side surface angle from an inner peripheral side to an outer peripheral side, the angle of which is equal to the maximum sheave angle αmax of the pulley. Minimum sheave angle αm
It is characterized in that it continuously changes up to an angle γmin equal to in.

When k is 0.0018 <k ≦ 0.021, if the side angle of the V-belt is constant, the difference between the side angle and the sheave angle α of the sheave surface of the pulley is 0.2 ° or more. According to the above-mentioned V-belt, when the torque capacity decreases, the V-belt has a minimum side sheave of the pulley from an angle γmax equal to the maximum sheave angle αmax of the pulley from the inner peripheral side to the outer peripheral side. Angle γmi equal to angle αmin
Since the V-belt continuously changes to n, the V-belt can come into contact with the sheave surface at a portion of the side surface at an angle corresponding to the sheave angle of the sheave surface, and a reduction in torque capacity can be effectively prevented. .

[0011]

Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. FIG. 1 is a cross-sectional view of a belt type CVT pulley according to an embodiment of the present invention, including a center axis of the pulley. In the drawing, reference numeral 1 denotes a pulley of the embodiment (the left half in the drawing). 1a) indicates a sheave surface. In this embodiment, the distance between the shafts between the input and output pulleys 1 (only one side is shown in the drawing) of the continuously variable transmission mechanism around which a V-belt (not shown) is wound is 160 mm, and the circumference of the V-belt is 700 mm. The pulleys 1 for input and output are set so that the misalignment amount becomes 0 at a gear ratio = 0.4, and the reference sheave angle α0 is 11 °.

The sheave surface 1a of the pulley 1 of this embodiment is
The contour curve of the sheave surface 1a in a section including the central axis of the pulley 1 has a smooth convex curve such that the sheave angle changes continuously as shown in FIG. It has been. That is, the sheave surface 1a here
Is a reference sheave angle α0 = 11 ° which is equal to the sheave angle of the conventional pulley having a constant sheave angle at a point of a radius R0 at which the gear ratio is 1, and the point of the radius R on the curve is
The axial distance x with respect to the point having the radius R0 is represented by the following quadratic equation.

(Equation 1)

Here, the relationship between the gear ratio and the sheave angle α at the point of the radius R is changed by a coefficient k, and k = 0.0
At the time of 08, it becomes as shown in FIG. The relationship between the gear ratio and the amount of misalignment at this time is as shown in FIG. 3, and the maximum amount of misalignment can be reduced by about 0.4 mm with respect to the conventional sheave surface having a linear cross-sectional profile. Understand.

That is, up to k = 0.021, the misalignment decreases as k increases, and when k = 0.021,
The relationship between the gear ratio and the sheave angle α is as shown in FIG. 4, and the relationship between the gear ratio and the misalignment amount is as shown in FIG.
The amount of misalignment always becomes substantially zero irrespective of the change in the gear ratio.

If k is made larger than 0.021, the deviation of the sheave angle from the reference sheave angle α0 increases, while the amount of misalignment increases. Therefore, in this embodiment, k is set in the range of 0 <k ≦ 0.021, and the other parts of the pulley 1 of this embodiment (such as a mechanism for changing the groove width) are the same as the conventional ones. Same as the pulley 1.

According to the pulley 1 of this embodiment, the amount of misalignment due to shifting at radially inner and outer positions with respect to the radial position of the gear ratio 1 can be reduced or eliminated according to the value of k. As a result, excessive wear and noise due to one-sided contact of the V-belt can be effectively reduced.

If the sheave angle is different from the side angle of the V-belt, the torque capacity of the V-belt may increase or decrease. To this end, the applicant of the present application has previously described in
Japanese Patent No. 18176 discloses a relationship between a difference between a side angle and a sheave angle of a V-belt and a slip limit torque ratio, and the relationship is as shown in FIG. Here, as shown in FIG. 6B, the side angle of the V-belt is γ,
The sheave angle is α. As is clear from this graph, when the difference (γ-α) between the side angle of the V-belt and the sheave angle is 0.2 ° or less, the slip limit torque ratio and, consequently, the torque capacity become larger than 1. Exceeds 0.2 °, the slip limit torque ratio may not be smaller than 1.

That is, FIG. 7 shows the relationship between the gear ratio and the sheave angle when k = 0.0018, and the difference between the side angle and the sheave angle of the V-belt at the maximum gear ratio at this time is about 0. .2 °, the value of k is 0 <k ≦ 0.001
In the range of 8, when the speed ratio is in the range of 1 or more and 2.5 or less, 0 <β−α ≦ 0.2 °, and the torque capacity increases.

Therefore, in the above-described embodiment, the pulley 1 used for the V-belt whose side surface angle γ is equal to the reference sheave angle α0 is used.
In particular, the value of k is set in the range of 0 <k ≦ 0.0018. According to the pulley 1, the gear ratio is 1
In the range of not less than 2.5 and not more than 2.5, the difference between the side angle γ = α0 of the V-belt and the sheave angle α of the sheave surface can be not more than 0.2 °, and the torque capacity can be increased. In addition, as shown in FIG. 8, the amount of misalignment at that time can be reduced by a maximum of about 0.1 mm with respect to a conventional sheave surface having a linear cross-sectional profile.

When the coefficient k is 0.0018 <k ≦ 0.021
If the side angle of the V-belt is constant, the torque capacity may decrease. 9 and 15
FIG. 3 is a cross-sectional view showing two embodiments of a pulley V-belt of the present invention for preventing such a decrease in torque capacity. In the V-belt 2 of these two embodiments, the side angles of both side surfaces 2a are respectively reduced. , Continuously changes from the maximum side angle γmax on the outer side (upper side in the figure) to the minimum side angle γmin on the inner side. The other points are the same as those of the conventional V belt 2.

The above γmax and γmin are, as shown in FIG. 10, particularly k is 0.0018 <k ≦ 0.0.
21, the maximum sheave angle αm of the portion of the pulley 1 of the above embodiment set to the maximum radius Rmax of the sheave surface 1a.
ax and the minimum sheave angle αm of the minimum radius Rmin
in respectively.

According to the V-belt 2 of this embodiment, the side surface 2a can come into contact with the sheave surface 1a at an angle corresponding to the sheave angle of the sheave surface 1a, thereby effectively preventing a decrease in torque capacity. be able to.

In the above embodiment, the sheave surface has a sectional profile curve expressed by a quadratic equation. In the present invention, however, the minimum sheave angle αm with respect to the reference sheave angle α0
It is also possible to reduce the amount of misalignment by expressing the shape by the angle difference Δα of in. That is, in the above quadratic equation, k
= 0 when Δα = 0 ° and when k = 0.02 Δα =
From 0 °, if 0 ° <Δα ≦ 2.4 °, the amount of misalignment can be reduced.

FIG. 14A is a characteristic diagram showing the relationship between the difference between the side angle of the V-belt and the sheave angle, and the vibration acceleration of the V-belt, obtained by experiments. As shown in FIG. 3, the side angle of the side surface 2a of the V-belt 2 is γ, and the sheave angle of the sheave surface 1a of the pulley 1 is α. FIG.
As is clear from the characteristic diagram of (a), the difference (γ-α) between the side angle of the V-belt and the sheave angle is 0.15 ° or more and 0.1 °.
When the angle is 35 ° or less, the vibration acceleration is equal to or less than a preferable predetermined threshold.

Further, when used as a transmission for an automobile, it is frequently used in a state in which the gear ratio is at a minimum. Therefore, it is necessary to reduce the belt vibration acceleration when the gear ratio is at a minimum. Therefore, when the speed ratio is minimum, that is, in a state where the V belt is located at the minimum radius portion of the driven pulley, the side angle γ of the V belt = γ0 and the minimum sheave angle α
If the difference Δα from min is 0.15 ° ≦ Δα ≦ 0.35 °, the amount of misalignment can be reduced and the vibration acceleration can be reduced.

Although the present invention has been described with reference to the illustrated examples, the present invention is not limited to the above examples, but can be appropriately modified within the scope of the claims. In the embodiment, the sheave surface has a sectional profile curve represented by a quadratic equation or a difference between the reference sheave angle and the minimum sheave angle, but the misalignment is reduced or set to zero. It is also possible to have a sectional profile curve represented by such an empirical formula.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of a belt type CVT pulley of the present invention, including a central axis of the pulley.

FIG. 2 is a relationship diagram showing the relationship between the gear ratio of the pulley and the sheave angle α in the embodiment when k = 0.008.

FIG. 3 is a relationship diagram showing the relationship between the gear ratio and the amount of misalignment between the pulley of the embodiment and the conventional pulley when k = 0.008.

FIG. 4 is a relationship diagram showing the relationship between the gear ratio of the pulley and the sheave angle α in the embodiment when k = 0.021.

FIG. 5 is a relationship diagram showing the relationship between the gear ratio of the pulley of the above embodiment and the conventional pulley and the amount of misalignment when k = 0.021.

FIG. 6A is a relationship diagram showing a relationship between a difference between a side angle and a sheave angle of a V-belt and a slip limit torque ratio;
(B) is an explanatory view illustrating the side angle γ and the sheave angle α of the V-belt.

FIG. 7 is a relationship diagram showing the relationship between the gear ratio of the pulley and the sheave angle α in the embodiment when k = 0.0018.

FIG. 8 is a relationship diagram showing the relationship between the gear ratio of the pulley of the above embodiment and the conventional pulley and the amount of misalignment when k = 0.0018.

FIG. 9 is a cross-sectional view showing one embodiment of the pulley V-belt of the present invention.

FIG. 10 is a sectional view showing a pulley in which the V-belt of the embodiment shown in FIG. 9 is used, including a central axis of the pulley.

FIG. 11 is a sectional view showing an example of a conventional belt-type CVT pulley and a V-belt, including a central axis of the pulley.

FIG. 12 is a relationship diagram showing a relationship between a gear ratio and a misalignment amount between a conventional pulley having a constant sheave angle and a conventional pulley having a two-stage sheave angle.

FIG. 13 is a sectional view showing an example of a conventional pulley in which the sheave angle is set in two stages, including a central axis of the pulley.

14A is a characteristic diagram showing a relationship between a difference between a side angle of a V-belt and a sheave angle and a vibration acceleration, and FIG.
FIG. 4 is an explanatory diagram illustrating a side angle γ and a sheave angle α of a V-belt.

FIG. 15 is a sectional view showing a further embodiment of the pulley V-belt of the present invention.

[Explanation of symbols]

 1 Pulley 1a Sheave surface 2 V belt 2a Side surface α Sheave angle α0 Reference sheave angle αmax Maximum sheave angle αmin Minimum sheave angle γ Side angle γmax Maximum side angle γmin Minimum side angle x distance

Claims (6)

[Claims] 1. A sheave surface of a pulley for a belt type CVT,
A belt-type CVT pulley, wherein a contour curve in a cross section including a center axis of the pulley is a smooth convex curve in which a sheave angle changes continuously. 2. An axial distance x from a radius R0 point of a gear ratio 1 to a radius R point of a contour curve of a section of the sheave surface including a center axis of the pulley is a reference sheave angle α.
0, for the minimum radius Rmin, x = R × tanα0 + {k / (R0−Rmin)} ×
(R-R0) ² , wherein k is 0 <k ≦ 0.021,
The pulley for a belt type CVT according to claim 1. 3. The angle α0 whose side angle is equal to said reference sheave angle.
3. The pulley according to claim 1, wherein the k is 0 <k ≦ 0.0018. 4. 4. The value of k is 0.0018 <k ≦ 0.021.
3. The V-belt used for a belt type CVT pulley according to claim 2, wherein a side surface angle from an inner peripheral side to an outer peripheral side is equal to a maximum sheave angle αmax of the pulley from an angle γmax equal to a minimum sheave angle αmin of the pulley. A V-belt for pulleys, wherein the V-belt continuously changes up to an angle γmin equal to: 5. A surface angle α0 equal to said reference sheave angle.
The belt type according to claim 1, wherein in the pulley used for the V-belt, an angle difference Δα between a minimum sheave angle αmin and a reference sheave angle α0 is 0 ° <Δα ≦ 2.4 °. Pulley for CVT. 6. The angle difference Δα is 0.15 ° ≦ Δα ≦
The belt type CVT pulley according to claim 5, wherein the angle is 0.35 °.