JP3663969B2 - Assembly type transmission V belt - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an assembly-type transmission V-belt that is used across a pair of V-groove pulleys in a V-belt type continuously variable transmission or the like.
[0002]
[Prior art]
KD transmission V-belt of such applications as shown by 1 in Figure 1, is rotated and the pulley V grooves of the input pulley 11 which is driven to rotate around the axis O _i, an axis parallel O _o around the axis O _i It is spanned between the output pulley 12 and the pulley V groove for practical use.
In such a winding transmission system, the rotation of the input pulley 11 is transmitted to the output pulley 12 via the assembly-type transmission V-belt 1.
During this transmission, if the movable flange of the opposing flanges forming the pulley V grooves of both pulleys 11 and 12 is displaced in the same axial direction, the assembly type transmission V belt 1 is wound around the input / output pulleys 11 and 12. The hanging arc diameter changes continuously, and continuously variable transmission can be performed.
[0003]
Here, the assembly-type transmission V-belt 1 will be described below with reference to FIG. 2 as well. Conventionally, as described in, for example, Japanese Patent Laid-Open No. 2-14634, each of the opposing transmission V-belts 1 is provided with an opposing flange that forms a pulley V-groove. A large number of V-shaped blocks 2 having inclined end surfaces 2a that make frictional contact are provided, and these V-shaped blocks 2 are continuously arranged in an endless manner so that a V-belt is formed as shown in FIG.
A pair of endless bands 3 are wound around the shoulder portions 2b at both ends of the V-shaped block 2, and each endless band 3 is formed of a laminate of endless band elements 3a.
The V-shaped block 2 is further provided with a neck portion 2c arranged between the shoulder portions 2b on both sides, and an arm portion 2d extending from the neck portion 2c so as to face the shoulder portion 2b. The V-shaped block 2 is prevented from coming off from the endless band 3.
[0004]
However although the conventional has been described in the literature, the shoulder portion 2b of the V-block 2 to wound the endless band 3 respectively, the radius of curvature as viewed in the direction of belt travel as clearly shown in Figure 2 is R ₁ In general, the crowning surface is curved so as to have a middle height so that the endless band 3 is automatically aligned in the band width direction with respect to the shoulder 2b during transmission.
[0005]
[Problems to be solved by the invention]
However, when the shoulder 2b is configured to be a crowned surface that is curved so as to have a medium height for the automatic alignment, particularly when the endless band 3 wound around the shoulder 2b is in a region where the pulleys 11 and 12 are wound. It was confirmed that the middle part in the width direction of the endless band 3 is inevitable in terms of stress.
FIG. 3 shows a state in which the assembly type transmission V-belt 1 is in the state of FIG. 1 wound around the pulleys 11 and 12, that is, when the input pulley 11 is a small diameter pulley and the output pulley 12 is a large diameter pulley. The endless band for each running region (3) The tensile stress on the outer peripheral surface was measured at each part in the band width direction. As is clear from this figure, the endless band 3 is in the region where the pulleys 11 and 12 are wound. In the middle in the width direction, a large tensile stress is applied, which is disadvantageous in strength.
This tendency is particularly prominent when the endless band 3 is in a region around the small-diameter pulley 11.
[0006]
In the first aspect of the present invention, the tensile stress on the outer peripheral surface of the endless band varies greatly depending on the ratio of the curvature radius in the width direction of the endless band to the curvature radius of the crowning surface as viewed in the belt running direction. In view of the above facts, by appropriately determining this ratio, the tensile stress on the outer peripheral surface of the endless band can be relaxed more than in the past, thereby proposing an assembly type transmission V-belt that realizes the above-mentioned problem solving. Objective.
[0007]
According to a second aspect of the present invention, in the assembly type transmission V in which the above ratio is determined so that the function and effect of the first aspect of the invention can be reliably achieved even when there is a variation due to manufacturing errors in both the radii of curvature. The purpose is to propose a belt.
[0008]
[Means for Solving the Problems]
For these purposes, first, the assembly-type transmission V-belt of the first invention is
A large number of V-shaped blocks each having an inclined end surface that is in frictional contact with both side walls of the pulley V-groove are continuously arranged in an endless manner so as to form a V-belt, and there is no need for the crowning surfaces of these V-shaped blocks. Assuming an assembly-type transmission V-belt assembled by wrapping a terminal band,
The ratio of the radius of curvature in the width direction of the endless band to the radius of curvature of the crowning surface viewed in the belt traveling direction is set to 0.21 or more and 0.35 or less.
[0009]
The assembly type transmission V belt according to the second invention is the above-mentioned first invention,
The ratio is set to 0.25 or more and 0.35 or less.
[0010]
【The invention's effect】
The assembly type transmission V-belt of the first invention has a ratio of the radius of curvature in the width direction of the endless band to the radius of curvature seen in the belt running direction of the crowning surface provided in each V-shaped block to wind the endless band. Since it was set to 0.21 or more and 0.35 or less,
Even if the surface of each V-shaped block around which the endless band is wound is a crowning surface for automatic centering in the band width direction of the endless band, the tensile force received by the outer peripheral surface of the endless band in the winding region with respect to the pulley The stress can be made smaller than that of the prior art, and the disadvantage that the outer peripheral surface of the endless band becomes disadvantageous in terms of stress and causes the above-mentioned problem in strength can be avoided.
[0011]
Since the assembly type transmission V-belt of the second invention sets the ratio of the above-mentioned curvature radii to 0.25 or more and 0.35 or less, the following effects can be obtained.
That is, when the ratio of both radii of curvature is less than 0.25, the change of the tensile stress on the outer peripheral surface of the endless band with respect to the change of the ratio of both radii of curvature becomes steep, and the both radii of curvature due to manufacturing errors. Even if there is a variation, the tensile stress acting on the outer peripheral surface of the endless band may become larger than that of the conventional one, and the effect of the first invention may not be achieved, but the ratio of the two radii of curvature is 0.25 or more, In the case of the second invention of 0.35 or less, since the steep region is not used, such an adverse effect does not occur, and the operational effect of the first invention can be ensured regardless of the variation in both the curvature radii. Can be a thing.
[0012]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.
4 and 5 show a V-shaped block 2 and an endless band 3 constituting an assembly type transmission V belt according to an embodiment of the present invention.
In the present embodiment, not only the shoulder portion 2b of the V-shaped block 2 that spans the endless band 3 is a crowning surface that is curved to a medium and high when viewed in the band traveling direction as shown in FIG.
The endless band 3 is also curved so as to have a middle height in the band width direction, as shown in FIG. 5, corresponding to the crowning surface of the shoulder 2b.
[0013]
Here, the ratio (R ₂ / R ₁ ) of the radius of curvature R ₂ of the endless band 3 to the radius of curvature R ₁ of the crowning surface 2b viewed in the belt traveling direction under the assembly-type transmission V-belt of various specifications. When the maximum tensile stress σ _max on the outer peripheral surface of the endless band 3 was measured in various ways, a relationship as shown in FIG. 6 exists between them, and the magnitude of the tensile stress on the outer peripheral surface of the endless band 3 is large. It was confirmed that the length depends not on the radius of curvature R ₁ and R ₂ but on the ratio between them.
[0014]
For reference, FIG. 7A shows the tensile stress σ acting on the outer peripheral surface of the endless band 3 in the case where the radius of curvature ratio (R ₂ / R ₁ ) corresponds to the point a in FIG. (B), (c), and (d) show the curvature radius ratio (R ₂ / R ₁ ) of point b (point R ₂ / R ₁ = 0.25) and point c in FIG. , A tensile stress σ acting on the outer peripheral surface of the endless band 3 in a case corresponding to the point d.
In any of FIGS. 7A, 7B, 7C, and 7D, the tensile stress σ acting on the outer peripheral surface of the endless band 3 is different for each traveling region of the endless band 3 and the band width. It is the result measured in each direction part.
[0015]
The maximum tensile stresses on the outer surface of the endless band (3) in FIGS. 7 (a), (b), (c), and (d) are σ _amax , σ _bmax , σ _cmax , and σ _dmax , respectively. Similarly, the maximum tensile stress of the outer peripheral surface of the endless band measured with respect to other curvature radius ratios (R ₂ / R ₁ ) is plotted as shown by points a, b, c, and d. By plotting above, the relationship diagram of FIG. 6 can be obtained.
By the way, in the region of a large curvature radius ratio of R ₂ / R ₁ ≧ 0.25 from the point b in FIG. 6 (point of R ₂ / R ₁ = 0.25), FIGS. ), (D), the endless band 3 receives the maximum tensile stresses σ _bmax , σ _cmax , σ _dmax on the central surface in the bandwidth direction of the outer peripheral surface at the small diameter pulley winding portion,
In the region of a small radius of curvature ratio of R ₂ / R ₁ <0.25, as is apparent from FIG. Subject to stress σ _amax .
[0016]
In the prior art, however, the endless band 3 was not curved in the bandwidth direction as shown in FIG. 2, so that the endless band 3 was curved in the band width direction in the pulley winding region due to the band tension in use. Even if this occurs, the radius-of-curvature ratio (R ₂ / R ₁ ) never becomes 0.35 or less, and it has been put to practical use in the region of the radius of curvature indicated by α in FIG.
For this reason, as described above, when the endless band 3 is in the region where the small-diameter pulley 11 is wound around, it is inevitable that the middle portion in the band width direction receives a large tensile stress and is disadvantageous in terms of strength.
[0017]
Therefore, in the present embodiment, as described above, the endless band 3 is also curved so as to have a middle height in the band width direction as shown in FIG. 5 in correspondence with the crowning surface of the shoulder 2b. its radius of curvature R _2, the ratio of the radius of curvature R ₂ of the endless band 3 with respect to the radius of curvature R ₁ of the crowning surface 2b as seen in the direction of belt travel (R ₂ / R ₁₎ is endless band (3) the outer peripheral surface Te The curvature radius is set so as to guarantee the reduction of the maximum tensile stress.
Considering the radius-of-curvature ratio (R ₂ / R ₁ ) that enables the guarantee, the radius-of-curvature ratio (R ₂ / R ₁ ) has never been less than 0.35 in the prior art. since but had received a large tensile stress in the band width direction middle portion, the curvature radius ratio (R ₂ / R ₁₎ may be determined radius of curvature R ₂ of the endless band 3 so as to be 0.35 or less .
[0018]
Then to consider the allowable lower limit value of the curvature radius ratio (R ₂ / R _1), pulling up of the endless band 3 when the curvature radius ratio (R ₂ / R ₁₎ is allowable upper limit value 0.35 as described above Since the stress is as shown by σ _jmax in FIG. 6, the region of the curvature radius ratio (R ₂ / R ₁ ) that _makes the maximum tensile stress of the endless band 3 less than σ _jmax , that is, β in FIG. The lower limit value 0.21 of the curvature radius ratio (R ₂ / R ₁ ) that defines the region to be shown is the allowable lower limit value of the curvature radius ratio (R ₂ / R ₁ ) to be obtained.
Accordingly, the curvature radius ratio (R ₂ / R ₁₎ may be determined radius of curvature R ₂ of the endless band 3 so as to be 0.21 or more.
[0019]
In the present embodiment, in view of the above fact, the endless band 3 is curved so as to have a middle height in the band width direction corresponding to the crowning surface 2b of the V-shaped block 2, and in addition, the radius of curvature R ₂ is The curvature radius ratio (R ₂ / R ₁ ) with respect to the curvature radius R ₁ of the crowning surface 2b is determined to be a value within the range indicated by β in FIG. 6, that is, 0.21 or more and 0.35 or less.
Therefore, in the present embodiment, even if the surface 2b of the V-shaped block around which the endless band 3 is wound is used as a crowning surface for automatic band alignment, the maximum tensile stress received by the outer peripheral surface of the endless band 3 As can be clearly seen from FIG. 6, the outer peripheral surface of the endless band 3 is disadvantageous in terms of stress, thereby avoiding the adverse effect of causing the above-mentioned strength problem.
[0020]
As is clear from FIG. 6, in the region where the radius-of-curvature ratio (R ₂ / R ₁ ) is less than 0.25, the endless band 3 is maximum on both end faces in the bandwidth direction of the outer peripheral surface as shown in FIG. Since the tensile stress σ _amax is received, the change in the maximum tensile stress σ _{max on} the outer surface of the endless band (3) with respect to the change in the radius-of-curvature ratio (R ₂ / R ₁ ) becomes steep, and both the above-mentioned curvatures due to manufacturing errors Even if the radii R ₁ and R ₂ vary, there is a case where the possibility that the radius-of-curvature ratio (R ₂ / R ₁ ) becomes less than the allowable lower limit value 0.21 cannot be completely wiped out.
In this case, the maximum tensile stress acting on the outer peripheral surface of the endless band 3 becomes larger than that of the conventional one, so that the above-mentioned effects cannot be achieved, and the original purpose cannot be achieved.
[0021]
In order to avoid this concern, the lower limit value of the radius-of-curvature ratio (R ₂ / R ₁ ) is set to the above 0.25, and a value within the range indicated by γ in FIG. 6, that is, 0.25 or more, 0.35 You can decide to be:
In such an embodiment, a region where the change in the maximum tensile stress σ _max of the endless band outer peripheral surface with respect to the change in the radius-of-curvature ratio (R ₂ / R ₁ ) becomes steep is not used. The possibility that the radius-of-curvature ratio (R ₂ / R ₁ ) may be less than the allowable lower limit of 0.21 due to variations in R ₁ and R ₂ can be eliminated. This causes the maximum tensile stress on the outer surface of the endless band. It is possible to eliminate the concern that it becomes larger than the conventional one and the original purpose cannot be achieved.
[Brief description of the drawings]
FIG. 1 is a side view showing a practical assembly-type transmission V-belt in a practical state in which a conventional assembly-type transmission V-belt is stretched between a pair of pulleys.
FIG. 2 is a cross-sectional view showing a conventional assembly-type transmission V-belt as a cross section in a plane crossing the belt running direction.
FIG. 3 is a three-dimensional diagram showing tensile stress acting on the outer peripheral surface of an endless band in a conventional assembly-type transmission V-belt for each belt travel region.
FIG. 4 is a front view of a V-shaped block of an assembly-type transmission V-belt according to an embodiment of the present invention.
FIG. 5 is a sectional view showing an endless band of the assembly-type transmission V-belt according to the same embodiment.
FIG. 6 shows the ratio of the curvature radius of the curvature radius of the endless band to the radius of curvature of the crowning surface provided in the V-shaped block for bridging the endless band in the assembly type transmission V-belt, and acts on the outer peripheral surface of the endless band. It is a diagram which shows the relationship with the largest tensile stress to do.
7A is a three-dimensional diagram showing the tensile stress acting on the outer peripheral surface of the endless band for each belt travel region when the curvature radius ratio at the point a in FIG.
(B) is a three-dimensional diagram showing the tensile stress acting on the outer peripheral surface of the endless band for each belt travel region when the curvature radius ratio at the point b in FIG.
(C) is a three-dimensional diagram showing the tensile stress acting on the outer peripheral surface of the endless band for each belt travel region when the curvature radius ratio at the point c in FIG.
FIG. 7D is a three-dimensional diagram showing the tensile stress acting on the outer peripheral surface of the endless band for each belt travel region when the curvature radius ratio at the point d in FIG. 6 is used.
[Explanation of symbols]
1 Assembly type transmission V belt 2 V type block
2a Inclined end face
2b Shoulder (crowning surface)
3 Endless band
11 Input pulley
12 Output pulley R ₁ Curvature radius of curvature R ₂ Endless band radius of curvature

Claims (2)

A large number of V-shaped blocks each having an inclined end surface that is in frictional contact with both side walls of the pulley V-groove are continuously arranged in an endless manner so as to form a V-belt, and there is no need for the crowning surfaces of these V-shaped blocks. In the assembly-type transmission V-belt assembled by winding the end band,
An assembly-type transmission V-belt characterized in that the ratio of the radius of curvature in the width direction of the endless band to the radius of curvature of the crowning surface as viewed in the belt running direction is set to 0.21 or more and 0.35 or less. The assembly-type transmission V-belt according to claim 1, wherein the ratio is set to 0.25 or more and 0.35 or less.

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