JP3181277B1 - Grooved pulley - Google Patents

Abstract

An object of the present invention is to improve the durability of a grooved pulley. SOLUTION: An outer cylindrical portion 5 of a tensioner pulley 50 is provided.
1 and the inner cylindrical portion 52 are provided coaxially. Outer cylindrical part 51
A groove 51A having a substantially V-shaped cross section is formed on the outer peripheral surface along the circumferential direction. End portion 51B of outer cylindrical portion 51 and inner cylindrical portion 5
The rib 53 that integrally connects the second end 52 </ b> A and the entire circumference in the circumferential direction has a truncated cone shape, and is inclined with respect to the inner cylindrical portion 52. The connecting portion 50C between the outer cylindrical portion 51 and the rib 53 is in close contact with the entire circumference. The free end of the inner cylindrical portion 52 extends around the entire axis PA
It is bent to the side to form an annular plate portion 52B. The inner cylindrical portion 52 is formed so that the radial thickness is smaller than the thickness of the rib 53.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a grooved pulley used for, for example, an automobile belt tensioner.

[0002]

2. Description of the Related Art Conventionally, in a belt system of an automobile engine, for example, a grooved pulley is used as a belt tensioner for applying a predetermined tension to a drive belt. The grooved pulley has an inner cylindrical portion and an outer cylindrical portion, and a V-shaped groove is formed on the outer peripheral surface of the outer cylindrical portion along the circumferential direction. A ball bearing is press-fitted on the inner peripheral surface of the inner cylindrical portion, and a drive belt is suspended on a part of the outer peripheral surface of the outer cylindrical portion. When the grooved pulley is pressed toward the drive belt via the tensioner arm to apply tension to the drive belt, a load is applied to the outer cylindrical portion, and accordingly, stress is generated inside the grooved pulley.

[0003]

However, due to restrictions on the outer diameter of the entire grooved pulley and restrictions on the radial clearance that must be maintained at a plus tolerance in order to maintain the strength of the ball bearing, etc. The thickness of the attached pulley is limited to a predetermined thickness. Therefore, there has been a problem that the above-mentioned load and the stress applied thereto are repeatedly generated for a long period of time, so that a crack is generated in a connection portion between the rib connecting the inner cylindrical portion to the outer cylindrical portion and the inner cylindrical portion.

[0004] The present invention has been made to solve the above problems, and has as its object to provide a grooved pulley with higher durability.

[0005]

A grooved pulley according to the present invention has an outer cylindrical portion having a plurality of substantially V-shaped grooves formed in the outer peripheral surface along a circumferential direction, and a coaxial with the outer cylindrical portion. , An inner cylindrical portion having a diameter smaller than the diameter of the outer cylindrical portion, one end of the outer cylindrical portion and one end of the inner cylindrical portion close to this end are formed in the entire circumferential direction. With a frusto-conical rib integrally connected over
The ribs are inclined at an angle to the inner cylinder and
The radial thickness of the inner cylindrical portion is smaller than the thickness of the rib.
And wherein the decoction.

Preferably, at the corner where the rib and the inner cylindrical portion intersect, the angle facing the outer cylindrical portion is larger than 90 degrees , or the connecting portion between the outer cylindrical portion and the rib is in close contact with the entire circumference.

The free end of the inner cylindrical portion is bent, for example, over the entire circumference toward the axis of the inner cylindrical portion.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. The pulley to which the embodiment according to the present invention is applied is used, for example, in a belt tensioner of a belt system for an automobile engine shown in FIG. The belt system 1 shown in FIG. 1 includes a driving pulley 10 attached to an output shaft of an engine, an air conditioner, a power steering device, and driven pulleys 11 and 1 for an alternator.
2, 13, idler pulleys 14 and 15, and a belt tensioner 20. A single drive belt 30 is suspended between each of these pulleys.

The belt tensioner 20 includes a cup 40 fixed to an engine block, and a tensioner pulley 50 provided rotatably with respect to the cup 40 about a pivot bolt 60 serving as a swing shaft. The tensioner pulley 50 is urged upward in the figure by urging means provided in the cup 40, which will be described later, and tensions the drive belt 30 by this urging force. The drive belt 30
Is mounted with the tensioner pulley 50 rotated to the position shown by the broken line in the figure.

FIG. 2 is a perspective view of a tensioner pulley 50 to which the embodiment according to the present invention is applied, and FIG. 3 is a cross-sectional view cut along a plane including the axis of the tensioner pulley. The tensioner pulley 50 includes an outer cylindrical portion 51 and an inner cylindrical portion 52.
And a rib 53. Outer cylindrical part 51 and inner cylindrical part 5
2 is provided coaxially. In FIG. 3, the axis PA of the outer cylindrical portion 51 and the inner cylindrical portion 52 is indicated by a chain line. On the outer peripheral surface of the outer cylindrical portion 51, a groove (hereinafter, “V-shaped groove”) 51A having a substantially V-shaped cross section is formed along the circumferential direction.

As shown in FIG. 3, the rib 53 is formed by connecting one end 51B of the outer cylindrical portion 51 and one end 52A of the inner cylindrical portion 52 close to the end 51B over the entire circumference in the circumferential direction. They are integrally connected. As is apparent from FIG. 3, the intersection of the end 51B and the end 52A is rounded over the entire circumference. The rib 53 has a truncated conical shape and is inclined with respect to the inner cylindrical portion 52. In other words, the rib 53 is linearly inclined toward the inside of the tensioner pulley 50. The angle of inclination of the rib 53 will be described later. Further, as is apparent from FIG. 3, a connecting portion 50C of the outer cylindrical portion 51 and the rib 53 is provided.
Is in close contact over the entire circumference. A free end which is an end opposite to the end connected to the rib 53 in the inner cylindrical portion 52 is bent toward the axis PA over the entire circumference to form an annular plate portion 52B. A corner portion 52C where the annular plate portion 52B and the inner cylindrical portion 52 intersect is rounded. The provision of the corners 52C increases rigidity and improves roundness.

FIG. 4 is an enlarged view of the end face shown on the left side in FIG. The V-shaped groove 51 </ b> A formed on the outer peripheral surface of the outer cylindrical portion 51 passes through the surface connecting the crest and the valley, the center of the groove valley, and the outer cylindrical portion 51 and the inner cylindrical portion 52
Is formed to have an angle a1 with respect to a plane perpendicular to the axis PA (see FIG. 3) of about 20 degrees. That is, the V-shaped groove 51
An angle a defined by a plane connecting a peak and a valley at A
2 is 40 degrees. The inclination angle a3 of the outer peripheral surface of the rib 53 with respect to a plane perpendicular to the axis PA of the outer cylindrical portion 51 and the inner cylindrical portion 52 is 20 degrees. The angle a4 formed by the inner peripheral surface of the inner cylindrical portion 52 on the annular space side formed by the outer cylindrical portion 51, the inner cylindrical portion 52, and the rib 53 and the inner peripheral surface of the rib 53 on the same annular space side is about 110 degrees. is there.

In the tensioner pulley 50, the thickness t1 in the radial direction of the inner cylindrical portion 52 is formed to be smaller than the thickness t2 of the rib 53. Specifically, the inner cylindrical portion 5
The thickness t1 of the rib 53 in the radial direction is in the range of about 1.4 mm to 1.6 mm, and the thickness t2 of the rib 53 is in the range of about 2.8 mm to 3.2 mm.
mm.

FIG. 5 is a bottom view of the tensioner pulley 50. FIG. Referring to FIGS. 3 and 5, serrations 51 </ b> C extending along the axis of the outer cylindrical portion 51 are formed on the inner peripheral surface of the outer cylindrical portion 51. The serrations 51C are formed as the V-shaped grooves 51A are formed. An intermediate formed body having the general shape of the tensioner pulley 50 obtained by press working is set on a predetermined core roll, and the roll is pressed with a predetermined load on the outer peripheral surface that is being rotated at a high speed. It is formed by plastic deformation.
On the outer peripheral surface of the above-mentioned core roll, which contacts the inner peripheral surface of the portion corresponding to the outer cylindrical portion 51 in the intermediate molded body, fine grooves extending along the axis are formed over the entire periphery at a predetermined pitch. This groove is for ensuring the escape of the excess thickness of the portion corresponding to the outer cylindrical portion 51 during the plastic deformation. Therefore, the serrations 51C are formed with the above-described pressing of the rolls.

When the V-shaped groove 51A is formed by plastic deformation, it is conceivable to use a mandrel in which a plurality of grooves are formed on the outer peripheral surface at a predetermined pitch along the circumferential direction. That is, inside the portion corresponding to the inner cylindrical portion of the intermediate molded body,
This is a method in which a mandrel is arranged so that the shaft center is eccentric to the axis of the intermediate molded body, and a roll is pressed with a predetermined load on the outer peripheral surface of the intermediate molded body that is being rotated at a high speed. Is formed along the circumferential direction on the inner peripheral surface of the outer cylindrical portion of the grooved pulley. However, according to the manufacturing method of the present embodiment, since the intermediate molded body is fixed by the core roll, when manufacturing a small-diameter pulley having an outer diameter of about 70 mm, the distance between the inner cylindrical portion and the outer cylindrical portion in the annular space, and the like, This is advantageous in satisfying higher dimensional accuracy as compared with the above-described eccentric manufacturing.

FIG. 6 is a sectional view showing a state in which the tensioner pulley 50 is provided on the automatic tensioner. The auto tensioner has a cup 40. A fixed portion 41 extends integrally with the cup 40 at a peripheral portion on the bottom surface side of the cup 40. A mounting hole 43 is formed in the fixing portion 41,
Bolts (not shown) are inserted. The bolt 40 fixes the cup 40 at a predetermined position on an engine block (not shown).

A hole 44 for fixing the rotating shaft member 60 is formed at the center of the bottom of the cup 40.
One end of the cylindrical portion 61 of the rotating shaft member 60 is press-fitted and fixed therein. The rotating shaft member 60 is formed of a metal material. A disc portion 62 is integrally provided on the free end side of the column portion 61. The diameter of the disk part 62 is larger than the diameter of the column part 61.

The arm 70 is a substantially disk-shaped metal member, and is attached to the opening 44 of the cup 40. The arm 70 has a bearing portion 71 extending toward the bottom surface of the cup, and the rotating shaft member 60 is inserted into a bearing hole 72 penetrating in an axial direction of the bearing portion 71. In the axial direction, the bearing hole 7
Numeral 2 is provided over about 2/3 of the axial length of the cylindrical portion 61, whereby the load received by the rotating shaft member 60 from the arm 70 is dispersed in the axial direction, and the fall due to the local load burden is prevented. Is done.

Since the diameter of the disk portion 62 is larger than the diameter of the bearing hole 72, the arm 70 is rotatably supported by the rotary shaft member 60, and the opening portion 44 and the disk portion 62 move in the axial center CA direction. Relative movement is regulated.

Two bearing members 80 and 90 are press-fitted into the bearing hole 72 from the upper and lower ends, respectively, and these frictionally slide with the outer peripheral surface of the rotary shaft member 60. Thereby, the arm 70 becomes rotatable around the axis CA. As a material of the bearing members 80 and 90, a synthetic resin having excellent wear resistance, for example, polytetrafluoroethylene (PTFE) is preferable.

The arm 70 on the tensioner pulley 50 side,
That is, a pulley mounting portion 74 protruding toward the tensioner pulley is integrally provided at one end of the upper end surface 73 in the drawing. The tensioner pulley 50 is mounted outside the pulley mounting section 74.

A ball bearing 75 is press-fitted between the pulley mounting portion 74 and the inner cylindrical portion 52, so that the tensioner pulley 50 can rotate around the axis PA of the inner cylindrical portion 52 with respect to the arm 70. Become. A washer 76 is fitted above the ball bearing 75 in the drawing, and a pulley bolt 77 is fitted from above the washer 76 and screwed and fixed to the pulley mounting portion 74. This restricts relative movement of the ball bearing 75 and the tensioner pulley 50 along the axis PA. Incidentally, as the ball bearing 75, for example, a 6203 type ball bearing or the like is used.

FIG. 7 is an enlarged view showing a press-fit portion of the ball bearing 75. As shown in FIG. Corner 7 of ball bearing 75
5A is rounded and disposed so as to provide a predetermined gap K between the tensioner pulley 50 and the annular plate portion 52B. As described above, the provision of the corner portion 52C increases rigidity and improves roundness. However, when the corner portion 75A of the ball bearing 75 and the corner portion 52B interfere with each other, a predetermined radial gap cannot be obtained, and the ball is not provided. The life of the bearing 75 is shortened. Therefore, the radius of curvature of the corner 52C is set smaller than the radius of curvature of the corner 75A. Thereby, the interference between the opposed corners described above is avoided, a predetermined radial gap is secured in the ball bearing 75, and the durability of the ball bearing 75 is improved. still,
In order to avoid interference with the ball bearing 75, an annular plate portion may not be provided at the free end of the inner cylindrical portion 152 as in the pulley 150 shown in FIG. The other configuration of the pulley 150 is the same as that of the tensioner pulley 50, and the description is omitted.

Referring again to FIG. 3, the arm 70 is rotated by the torsion coil spring 100 housed in the cup 40 in a predetermined rotation direction, that is, a direction in which the drive belt 30 (see FIG. 1) abutting the tensioner pulley 50 is tensioned. It is urged to. Thereby, an appropriate tension is applied to the belt.

On the inner peripheral surface near the opening 44 of the cup 40, a cylindrical damping band 11 is provided over substantially the entire circumference.
0 is in sliding contact. Damping band 110 is arm 7
0 and two ring springs 111 from inside
Accordingly, the cup 40 is urged toward the inner peripheral surface. When the arm 70 swings due to the vibration of the drive belt 30, the damping band 110 frictionally slides with the cup 40, and the swing of the arm 70 is braked. Thereby, the vibration generated in the drive belt 30 is effectively attenuated.

As described above, according to the present embodiment, the rib 5
3 is inclined at 20 degrees toward the press-fit portion of the ball bearing, and the inner cylindrical portion 52 and the rib 53 are connected to the tensioner pulley 5.
An angle of about 110 degrees is formed on the side of the 0 annular space. Therefore, a crack is generated in the connecting portion between the inner cylindrical portion 52 and the rib 53 due to factors such as the pressing force of the drive belt wound around the outer cylindrical portion 51 and the stress generated in the ball bearing and the inner cylindrical portion 52. Restrained,
The durability of the tensioner pulley 50 is improved.

According to the present embodiment, the thickness of the inner cylindrical portion 52 in the radial direction is smaller than the thickness of the rib 53. That is, a predetermined diameter of the inner cylindrical portion 52, which is a ball bearing press-fitting portion, is maintained while securing a sufficient thickness to form a V-shaped groove on the outer peripheral surface of the outer cylindrical portion 51. Therefore, ball bearings used for other flat pulleys and the like can be used. In this embodiment,
It is suitable for a small-diameter pulley, that is, a pulley whose outer diameter of the outer cylindrical portion 51 having the V-shaped groove is about 70 to 75 mm or less. In other words, the application of the present embodiment has an outer diameter of 70 mm.
mm is preferred, but the applicable pulley outer diameter is in the range of 65-80 mm.

Further, according to the present embodiment, the outer cylindrical portion 5
Since the connecting portion 50C between the rib 1 and the rib 53 is in close contact with the entire circumference, the plate thickness of the connecting portion 50C is approximately doubled, and the strength is increased, so that the durability of the tensioner pulley 50 is improved.

[0029]

As described above, according to the present invention, a more durable grooved pulley can be obtained.

[Brief description of the drawings]

FIG. 1 is a diagram schematically showing a belt system of an automobile engine.

FIG. 2 is a perspective view of a tensioner pulley to which the embodiment according to the present invention is applied;

FIG. 3 is a sectional view of a tensioner pulley.

FIG. 4 is a partially enlarged view of a cross section of the tensioner pulley.

FIG. 5 is a bottom view of the tensioner pulley.

FIG. 6 is a cross-sectional view showing a state where a tensioner pulley is provided on an auto tensioner.

FIG. 7 is an enlarged view showing a press-fit portion of the ball bearing in FIG. 7;

FIG. 8 is a sectional view showing a modified example of the tensioner pulley.

[Explanation of symbols]

 Reference Signs List 40 cup 50 tensioner pulley 51 outer cylindrical part 52 inner cylindrical part 53 rib 51A V-shaped groove 51C serration 52B annular plate part 70 arm 75 ball bearing

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A 4-84959 (JP, U) JP-A 58-144148 (JP, U) JP-A 2-128859 (JP, U) (58) Survey Field (Int.Cl. ⁷ , DB name) F16H 53/00-55/56

Claims (4)

(57) [Claims] 1. An outer cylindrical portion having a plurality of substantially V-shaped grooves formed in a circumferential direction on an outer peripheral surface thereof, provided coaxially with the outer cylindrical portion, and having a smaller diameter than the outer cylindrical portion. A truncated cone that integrally connects an inner cylindrical portion having a diameter, one end of the outer cylindrical portion and one end of the inner cylindrical portion close to the end over the entire circumference in the circumferential direction. And the rib is inclined at a predetermined angle with respect to the inner cylindrical portion, and the radial thickness of the inner cylindrical portion is the thickness of the rib.
A grooved pulley characterized by being smaller than the thickness . 2. The grooved pulley according to claim 1, wherein, at a corner where the rib and the inner cylindrical portion intersect, an angle facing the outer cylindrical portion is larger than 90 degrees. 3. The connecting portion between the outer cylindrical portion and the rib is in close contact with the entire circumference.
The pulley with a groove according to the item. 4. The grooved pulley according to claim 1, wherein the free end of the inner cylindrical portion is bent over the entire circumference toward the axis of the inner cylindrical portion.