JP2017166704A - Press pulley - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a press pulley that can enlarge an inside diameter of an inner cylinder part without changing an outside diameter of an outer cylinder part.SOLUTION: An annular tie part 13 tied to an end of an outer cylinder part 11, around which a belt is wound, and an end of an inner cylinder part 12 is formed as an arc-shaped cross-section annular bent part inside which a single arc surface 15 tied to an inside diameter surface of the outer cylinder part 11 and an outside diameter surface of the inner cylinder part 12 by a tangent line is provided. Thus, an inside diameter of the inner cylinder part 12 is enlarged.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a press pulley made of a press-formed product of a steel plate.

  Conventionally, the press pulleys described in Patent Documents 1 and 2 have been known as press pulleys used for an auxiliary machine driving belt and timing belt tensioner of an automobile engine or as an idler for securing a winding angle of the belt. ing.

  In the press pulley described in Patent Document 1, a belt winding part as an outer cylinder part around which the belt is wound, a press-fitting part as an inner cylinder part provided inside the belt winding part, and the belt winding part A side plate portion that connects the press-fitting portion is provided, and the belt winding portion and the press-fitting portion are bent in the same axial direction by pressing a steel plate.

  Also, the corners of the press-fitting part provided between the press-fitting part and the side plate part are combined arcs composed of a plurality of arcs, and between the press-fitting part and the arc, between the arcs and between the arc and the side plate part. All of these are connected by a tangent line, and the stress generated at the corners of the press-fitted part is reduced by increasing the curvature of the corners of the press-fitted part, thereby preventing breakage.

  On the other hand, in the press pulley described in Patent Document 2, similarly to Patent Document 1, a belt winding part as an outer cylinder part, an inner cylinder part provided on the inner side, an inner cylinder part and a belt It has an annular flange portion (corresponding to the side plate of Patent Document 1) in which the winding portion is continuously provided, and the corner portion formed by the inner cylinder portion and the flange portion is thickened, and the thickened portion is By gradually reducing the wall thickness until it reaches the reference wall thickness as it moves away from both sides, the portion where the maximum principal stress is applied and the vicinity thereof are prevented from being damaged by fatigue.

JP 2002-250429 A JP 2007-198402 A

  By the way, any press pulley described in Patent Literature 1 and Patent Literature 2 alleviates stress concentration by devising the shape of the corner portion provided in the connecting portion of the inner cylinder portion and the side plate portion, Although the load resistance is improved, since the side plate portion is provided between the outer tube portion and the inner tube portion, the inner diameter of the inner tube portion becomes significantly smaller than the outer diameter of the outer tube portion, Large size bearings cannot be installed. For this reason, in order to increase the load resistance and increase the load capacity by incorporating a large-sized bearing, it is necessary to increase the diameter of the outer cylinder portion, which causes a problem that the press pulley is increased in size.

  An object of the present invention is to increase the inner diameter of the inner cylinder part without changing the outer diameter of the outer cylinder part, and to increase the load capacity by enabling the incorporation of a large-sized bearing. A press pulley is provided.

In order to solve the above-described problems, in the present invention, an outer cylindrical portion around which a belt is wound, an inner cylindrical portion for fitting a bearing provided inside the outer cylindrical portion, and an end portion of the inner cylindrical portion And a press-formed press pulley having an annular connecting portion connected to an end portion of the outer cylindrical portion, wherein the connecting portion is tangent to the inner diameter surface of the outer cylindrical portion and the outer diameter surface of the inner cylindrical portion. A configuration in which an annular bent portion having an arc-shaped cross section having a single arc surface connected at the inside is adopted.

  As described above, the connecting portion connecting the outer cylinder portion and the inner cylinder portion is an annular bent portion having an arc cross section, and the inner side surface of the annular bent portion is tangent to the inner diameter surface of the outer cylinder portion and the outer diameter surface of the inner cylinder portion. By eliminating the need for the side plate portion of the press pulley shown in Patent Documents 1 and 2 as a single circular arc surface that is connected to each other, the inner diameter of the inner cylindrical portion can be increased without changing the outer diameter of the outer cylindrical portion. be able to. For this reason, it is possible to incorporate a large-size bearing and increase the load capacity.

  Here, when the curvature radius of the inner circular arc surface of the joint portion is Ri and the thickness of the steel plate as the press material is t, if the curvature radius Ri is less than 0.2 t, a large press pressure is applied to the formation of the press pulley. It becomes necessary and manufacturing becomes difficult, and cost increases. If the radius of curvature Ri exceeds 0.2 t, the inner diameter of the inner cylindrical portion is reduced, so that a large-sized bearing cannot be incorporated, and the load capacity cannot be increased. For this reason, it is preferable that the curvature radius Ri be in the range of 0.2 to 0.5 t.

  In the press pulley according to the present invention, when the outer surface of the connecting portion is a single arc surface tangentially connected to the outer diameter surface of the outer cylinder portion and the inner diameter surface of the inner cylinder portion, it is easy to ensure the dimensions of the press pulley. The structure of the press mold can be simplified. Moreover, the improvement of the lifetime of a press die can be expected.

  Further, when the plate thickness after the press working is in the range of 70 to 95% of the plate thickness t of the steel plate as the press material, the dimensional accuracy can be improved by adding the ironing step in the cold working.

  Furthermore, by adopting a steel sheet with a thickness t in the range of 1.6 to 4.0 mm as a steel sheet as a press material, a highly rigid press pulley can be obtained, and the load capacity is greatly increased. Can do.

  In the present invention, as described above, the connecting portion that connects the outer tube portion and the inner tube portion is an annular bent portion having a U-shaped cross section, and the inner surface of the outer tube portion and the inner tube portion on the inner side surface of the annular bent portion. By providing a single arc surface that is tangentially connected to the outer diameter surface, it is possible to increase the inner diameter of the inner cylinder portion without increasing the outer diameter of the outer cylinder portion. A large bearing can be incorporated, and the load capacity can be increased.

Sectional drawing which shows embodiment of the press pulley which concerns on this invention 2 is an enlarged cross-sectional view of a part of FIG. Sectional view showing a conventional press pulley

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 and 2 show an embodiment of a press pulley 10 according to the present invention. The press pulley 1 is made of a press-formed product of a steel plate, and includes an outer cylinder part 11 around which a belt is wound, an inner cylinder part 12 provided inside the outer cylinder part 11, and an end of the inner cylinder part 12. And an annular connecting portion 13 connected to the end portion of the outer cylindrical portion 11 and an inward flange portion 14 bent inward from the end portion of the inner cylindrical portion 12, and the bearing into the inner cylindrical portion 12 It can be used as a tension pulley or as an idler pulley by incorporating 20 units.

  The connecting portion 13 is an annular bent portion having a circular arc cross section and has a single arc surface 15 on the inner side. The inner arc surface 15 is formed on the inner diameter surface of the outer cylinder portion 11 and the outer diameter surface of the inner cylinder portion 12. Connected by tangent.

  The outer surface 16 of the connecting portion 13 is a single arc surface, and the outer arc surface 16 is connected to the outer diameter surface of the outer cylinder portion 11 and the inner diameter surface of the inner cylinder portion 12 by a tangent line.

  Here, when the thickness of the steel sheet as the press material forming the outer cylinder part 11, the inner cylinder part 12 and the joint part 13 is t, and the curvature radius of the inner arcuate surface 15 of the joint part 13 is Ri, the curvature radius Ri is If it becomes smaller than necessary, a large press pressure is required for forming the press pulley, which makes it difficult to manufacture and increases the cost. Further, when the curvature radius Ri becomes larger than necessary, the inner diameter of the inner cylindrical portion 12 is reduced, and a large-sized bearing cannot be incorporated. Therefore, in the embodiment, the radius of curvature Ri is in the range of 0.2 to 0.5 t.

  Further, when the plate thickness t becomes thinner than necessary, the steel plate as the press material has a low rigidity, and a press pulley having a large load capacity cannot be obtained. Further, when the plate thickness t becomes thicker than necessary, press molding cannot be performed. Therefore, a steel sheet having a thickness t in the range of 1.6 to 4.0 mm is used. By adopting such a steel plate and forming the press pulley 10, it is possible to obtain a press pulley 10 having a high rigidity and a large load capacity.

  FIG. 3 shows a conventional press pulley described in the prior art section of Patent Document 1, and includes an outer cylinder part 31, an inner cylinder part 32, and a connecting part 33 that connects the inner cylinder part 32 and the outer cylinder part 31. The connecting portion 33 has a side plate portion 33a, and the inner cylinder side corner portion 34 formed by the side plate portion 33a and the inner cylinder portion 32 is formed as a single arc on the inner cylinder portion 32 and the side plate portion 33a. Connected by tangent.

  In any of the press pulleys described in Patent Literature 1 and Patent Literature 2, stress concentration is reduced by devising the shape of the corner portion 34 existing between the inner cylinder portion 32 and the side plate portion 33a. Since all the press pulleys have the side plate portion 33a shown in FIG. 3, the inner cylindrical portion 32 has a larger outer diameter than the outer cylindrical portion 31 as described above. The inner diameter was remarkably reduced, and a large-sized bearing 35 could not be assembled.

  When the press pulley shown in FIG. 1 is compared with the press pulley shown in FIG. 3, in the press pulley 10 shown in FIG. 1, the connecting part 13 that connects the outer cylinder part 11 and the inner cylinder part 12 is an annular bent part having a U-shaped cross section. The side plate portion of the press pulley shown in FIG. 3 is connected to the inner surface of the outer tube portion 11 and the outer surface of the inner tube portion 12 as a single circular arc surface 15 as the inner side surface of the annular bent portion. The difference is that 33a is omitted.

  In this way, the connecting portion 13 that connects the outer cylindrical portion 11 and the inner cylindrical portion 12 is an annular bent portion having a U-shaped cross section, and the inner surface of the annular bent portion and the outer surface of the inner cylindrical portion 12 By providing the single circular arc surface 15 connected to the radial surface by a tangent line, the inner diameter φDi of the inner cylinder portion 12 can be increased without increasing the outer diameter φDo of the outer cylinder portion 11. As a result, a large-sized bearing 20 can be incorporated, and a press pulley with a large load capacity can be obtained.

  As shown in the embodiment, when the outer surface 16 of the connecting portion 13 is a single circular arc surface tangentially connected to the outer diameter surface of the outer cylinder portion 11 and the inner diameter surface of the inner cylinder portion 12, the dimension of the press pulley is guaranteed. It becomes easy and the structure of a press die can be simplified. Moreover, the improvement of the lifetime of a press die can be expected.

  In the embodiment, the thickness of each part such as the outer cylinder part 11 and the inner cylinder part 12 of the press pulley 10 after the press working is added by the addition of the ironing process in the cold working. The range is 70 to 95% of t. By adding the ironing step, the dimensional accuracy of the press pulley 10 can be improved.

11 outer cylinder part 12 inner cylinder part 13 connecting part 14 inner circular arc surface 15 inner circular arc surface

Here, when the radius of curvature of the inner circular arc surface of the joint portion is Ri and the thickness of the steel plate as the press material is t, if the radius of curvature Ri is less than 0.2 t, a large press pressure is required for forming the press pulley. It becomes necessary and manufacturing becomes difficult, and cost increases. On the other hand, if the radius of curvature Ri exceeds 0.5 t, the inner diameter of the inner cylinder portion is reduced, so that a large-sized bearing cannot be incorporated, and the load capacity cannot be increased. For this reason, it is preferable that the curvature radius Ri be in the range of 0.2 to 0.5 t.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 and 2 show an embodiment of a press pulley 10 according to the present invention. The press pulley 10 is made of a press-formed product of a steel plate, and includes an outer cylinder part 11 around which a belt is wound, an inner cylinder part 12 provided inside the outer cylinder part 11, and an end of the inner cylinder part 12. And an annular connecting portion 13 connected to the end portion of the outer cylindrical portion 11 and an inward flange portion 14 bent inward from the end portion of the inner cylindrical portion 12, and the bearing into the inner cylindrical portion 12 as 20 incorporated into Thus the tension pulley, or is used as an idler pulley.

Claims (5)

The outer cylinder part around which the belt is wound, the inner cylinder part for bearing fitting provided inside the outer cylinder part, and the annular connecting part connected to the end part of the inner cylinder part and the end part of the outer cylinder part In a press-pulled press pulley comprising:
The connecting portion is an annular bent portion having an arcuate cross section having a single arc surface on the inner side that is connected to the inner diameter surface of the outer cylinder portion and the outer diameter surface of the inner cylinder portion by a tangent line. Press pulley to do.   The press pulley according to claim 1, wherein the curvature radius Ri is in the range of 0.2 to 0.5t, where Ri is the curvature radius of the inner circular arc surface of the joint and t is the thickness of the steel sheet as the press material. .   The press pulley according to claim 1 or 2, wherein the outer surface of the connecting portion is a single circular arc surface that is connected to the outer diameter surface of the outer cylinder portion and the inner diameter surface of the inner cylinder portion by a tangent line.   The press pulley according to any one of claims 1 to 3, wherein a plate thickness after press working is in a range of 70 to 95% of a plate thickness t of a steel plate as a press material.   The press pulley according to any one of claims 1 to 4, wherein a thickness t of a steel plate as the press material is in a range of 1.6 to 4.0 mm.

Images