JP2798567B2 - One-way clutch - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a one-way clutch used, for example, for a starter of an automobile or a transmission of an automobile.

[0002]

2. Description of the Related Art A conventional one-way clutch is shown in FIG. This one-way clutch includes a plurality of sprags 51, 51, a metal inner cage 52 for holding an inner portion 51a of the sprag 51, and a plastic outer cage for holding an outer portion 51b of the sprag 51. 53,
An annular ribbon spring 55 for urging the sprag 51 in the clockwise direction in FIG. 5A is provided. The outer cage 53 and the inner cage 52 have flanges 53b and 52b at one end in the axial direction. The one-way clutch is mounted between an inner wheel and an outer wheel (not shown).

Since the outer cage 53 requires less strength than the inner cage 52 that holds the swinging portion of the sprag 51, the outer cage 53 is made of plastic to reduce the weight (Japanese Patent Application Laid-Open No. H10-163,028). 63-303232).

[0004] In the one-way clutch, the inner ring has a structure shown in FIG.
(A) When rotated clockwise, the inner part 5 of the sprag 51 is rotated.
Due to the frictional contact between the inner ring 1a and the sprag 51,
Since the inner ring 51 is tilted counterclockwise to the idling side around the inner portion 51a, the rotation torque of the inner ring is not transmitted to the outer ring, and the inner ring idles.

When the inner ring rotates counterclockwise in FIG. 5 (A), the sprags 51 rise clockwise about the inner portion 51a due to frictional contact between the inner portion 51a of the sprag 51 and the inner ring. The inner ring and the outer ring are locked by the wedge action of the sprags 51, and the rotational torque of the inner ring is transmitted to the outer ring.

[0006]

However, the above-mentioned conventional one-way clutch has a disadvantage that the weight reduction is insufficient because the inner retainer 52 is made of metal.

Further, when the inner retainer 52 is made of resin in order to achieve a sufficient weight reduction, there are the following problems. That is, as shown in FIGS. 4A and 4B, when the one-way clutch changes from the free state to the locked state, the sprag swings largely on the inner cage side with the outer cage side as a fulcrum. Therefore, when a phase difference of the swing of the sprags in the pocket part of the inner cage (difference in the inclination angle between the sprags) occurs, tensile stress is generated in the pocket part in the direction of breaking the inner cage. I do. For this reason, even if the inner retainer is made of a strong resin such as glass fiber or reinforced plastic, the inner retainer will be broken when the sprag swings.

As a specific example, the outer diameter of the one-way clutch shown in FIG. 5 is 53.9 mm, the inner diameter is 37.2 mm, and as shown in FIG. Pillar 52
c between adjacent windows, that is, one pillar 52c
The dimension between the inner edges of the two pillars 52c, 52c
When the inner cage 52 is 2.3 mm, when the inner cage 52 is made of reinforced plastic obtained by adding 25% of glass fiber to nylon 66, the result of the expansion / contraction test of the inner cage 52
FIG. 6 shows the results of the tensile test.

[0009] In Fig. 6, "-" indicates the test results of the separate samples of the inner cage 52, and the horizontal axis indicates the inner cage 52.
Shows the amount of elongation between the windows. The vertical axis indicates the inner cage 52
Shows the force pulling the column in the circumferential direction. From the test results of the five samples of the inner cage 52, it can be seen that the inner cage breaks when the spread of the dimension between the windows exceeds 2.2 mm.

For this reason, when the one-way clutch incorporating the inner cage is changed from the free state to the locked state, the inner cage is broken. In other words, at this time, the interval between two adjacent sprags in the window portion of the inner cage was extended by 2.2 mm and opened to 14.5 mm or more.

SUMMARY OF THE INVENTION An object of the present invention is to provide a one-way clutch which can realize a sufficient weight reduction without damaging the cage.

[0012]

SUMMARY OF THE INVENTION In order to achieve the above object, the present invention provides an inclined position which is disposed at a predetermined interval in a circumferential direction between an inner ring and an outer ring and locks the inner ring and the outer ring. A plurality of sprags swinging between an inclined position for unlocking the inner ring and the outer ring, an inner cage for holding an inner portion of the sprag, and an outer cage for holding an outer portion of the sprag, In the one-way clutch provided with a spring for urging the sprag in one direction, the outer cage and the inner cage are made of plastic, and the elastic coefficient of the plastic used for manufacturing the inner cage is determined by the outer cage. The elasticity of the plastic used for the production of the inner cage is made smaller than the elastic modulus of the plastic used for the production of the inner retainer. It is characterized in that the plastics such as the maximum amount of deformation generated between the pillars of the inner retainer can be absorbed by the strain within the elastic limit of the inner cage by a difference in inclination angle between grayed.

That is, an important feature of the present invention is that when a tensile stress is applied between the columns of the inner cage, the characteristic A shown in FIG.
As shown in FIGS. 1 and A2, the inner cage is moved up to the deformation amount Z1 or Z2 larger than the maximum deformation amount X generated between the pillars of the inner cage due to the phase difference of the sprags (the difference in the inclination angle between the sprags). The inner cage is made of plastic that can be prevented from breaking or being permanently deformed.

[0014]

According to the above construction, the sprag swing phase difference of the sprags when changing from the free state (unlocked state) in which the inner wheel idles relative to the outer wheel to the locked state in which the inner wheel is restrained by the inner wheel.
Even if deformation occurs between the columns due to (difference in tilt angle), the deformation is within the elastic limit of the inner cage, so that the inner cage is not damaged.

That is, according to the present invention, the sprags that are pulled or fall when the free state is changed to the locked state are pressed and held by the metal cage or the strong resin inner cage. Instead, the inner cage is elastically deformed to allow a swing phase difference (difference in tilt angle) of the sprags, so that damage to the inner cage can be avoided.

As described above, according to the present invention, not only the outer cage but also the inner cage can be made of plastic without causing damage to the inner cage, and a sufficient weight reduction can be achieved. In addition, since both the outer cage and the inner cage are made of plastic, the collision sound when the sprag and the cage collide,
It can be reduced as compared with the conventional example.

[0017]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a perspective view of a one-way clutch according to the present invention.

FIG. 1 shows an embodiment of the present invention. The one-way clutch of this embodiment includes a plurality of sprags 1 and an inner cage 2.
And an outer retainer 3 and an annular ribbon spring 5,
It is mounted between an inner ring and an outer ring (not shown).

The inner retainer 2, the outer retainer 3 and the ribbon spring 5 have windows 2a, 3a and 5a provided at regular intervals in the circumferential direction, respectively. The inner cage 2 holds the inner portion 1a of the sprag 1 fitted in the window 2a, and the outer cage 3 holds the sprag 1 fitted in the window 3a.
Is held outside. Further, the ribbon spring 5 urges the sprags 1 fitted in the windows 5a in a direction in which the sprags 1 mesh with the inner ring and the outer ring (clockwise in FIG. 1A).

The outer retainer 3 has a flange 3b extending radially outward from one end in the axial direction. The inner cage 2 has a flange 2b extending radially inward from one end in the axial direction.

The circumscribed diameter of the one-way clutch is 5
It is 3.9 mm and the inscribed diameter is 37.2 mm. As shown in FIG. 1 (c), the dimension between the outer ends in both circumferential directions of the adjacent windows 2a sandwiching the column 2c of the inner cage 2 is 12.3.
mm.

The outer cage 3 and the inner cage 2 are made of plastic. That is, the outer cage 3 is made of glass fiber reinforced nylon 66 resin, and the inner cage 2 is made of a resin (trade name: DuPont ST-801) obtained by synthesizing nylon 66 and ethylene propylene rubber. The elastic modulus of the resin obtained by synthesizing the nylon 66 and the ethylene propylene rubber is smaller than the elastic modulus of the glass fiber reinforced nylon 66 resin. The results of the expansion / contraction test of the inner cage 2 are shown in FIG. 2 to 6 show the test results of the respective separate samples. 2, the horizontal axis represents the window 2a of the inner cage 2.
2a and 2a show the elongation of the dimension between the outer ends in both circumferential directions. Also,
The vertical axis indicates the force pulling the inner cage 2 from both sides in the radial direction.
As shown in FIG. 2, from the results of the stretching test on the five samples of the inner cage 2, the inner cage 2
It can be seen that when the elongation of the dimension between 2a and 2a exceeds 10 mm, fracture occurs.

In the one-way clutch constructed as described above, when the inner race rotates clockwise in FIG. 1 (A), the sprags 1 center on the outer race 1b due to frictional contact between the inner part 1a of the sprag 1 and the inner race. Tilts counterclockwise to the idling side,
The rotation torque of the inner wheel is not transmitted to the outer wheel, and the inner wheel idles.

When the inner ring rotates counterclockwise in FIG. 1A, the sprags 1 are raised clockwise about the outer portion 1b by frictional contact between the inner portion 1a of the sprag 1 and the inner ring. The inner ring and the outer ring are locked by the wedge action of the sprag 1, and the rotational torque of the inner ring is transmitted to the outer ring.

In this embodiment, as shown in FIG. 4, when the state changes from the free state in which the inner ring idles with respect to the outer ring to the locked state in which the inner ring restrains the outer ring, the swing phase difference of the sprags 1, 1,... Even if a tensile stress due to (difference in inclination angle) is applied to the column 2c between the windows 2a, 2a of the inner cage 2, the inner cage 2 is not deformed because it is only deformed within the elastic limit. .

That is, according to the above-described embodiment, the sprags 1, 1,... Which are pulled or fall when the free state is changed to the locked state are replaced with the metal cage or the strong resin inner cage. Instead of holding it down, the maximum strain within the elastic limit of the inner cage 2, ie,
When the extension between the windows is within the range of 10 mm, the maximum extension between the outer ends of the windows 2a and 2a of the inner cage 2 can be absorbed, so that the damage of the inner cage 2 can be avoided.

As described above, according to the above embodiment, not only the outer cage 3 but also the inner cage 2 can be made of plastic without causing the inner cage 2 to be damaged. it can.

Further, since both the outer retainer 3 and the inner retainer 2 are made of plastic, a collision sound or the like when the sprag and the retainer collide can be reduced as compared with the conventional example. Since the resin obtained by synthesizing the nylon 66 and the ethylene propylene rubber, which are the materials of the inner cage 2, has heat resistance of up to 165 ° C., the inner cage 2 is sufficient as a one-way clutch holder. Has excellent heat resistance.

That is, the above-described embodiment has the same sprag holding ability, apart from the point of firmly holding and the point of holding flexibly, in addition to the metal inner cage. Since the inner retainer is much lighter than that of the first embodiment, a great reduction in weight can be achieved.

In the above-described embodiment, as the material of the inner cage 2, a resin obtained by synthesizing nylon 66 and ethylene propylene rubber was used. However, the material of the inner cage 2 is not limited to this. As a material of 2, a flexible thermoplastic resin such as nylon 6, nylon 66, polyacetal, polyethylene, polypropylene, polycarbonate, polyethylene terephthalate, polybutylene terephthalate, or the like can be used.

[0031]

As is apparent from the above description, in the one-way clutch of the present invention, the outer retainer and the inner retainer are made of plastic, and the elastic coefficient of the plastic used for producing the inner retainer is set to the above value. The plastic used for manufacturing the inner cage is smaller than the elastic modulus of the plastic used for manufacturing the outer cage, and the maximum deformation generated between the columns of the inner cage is set within the elastic limit of the inner cage. It is made of plastic so that it can be absorbed by distortion.

Therefore, according to the present invention, when the free state in which the inner wheel idles with respect to the outer wheel changes from the free state in which the inner wheel locks to restrain the outer wheel, the swing phase difference of the sprags is changed.
Even if a tensile stress due to (difference in tilt angle) is generated in the column of the inner cage, the inner cage is only deformed within the elastic limit, so that breakage can be avoided.

As described above, according to the present invention, since both the outer cage and the inner cage are made of plastic without damaging the inner cage, a sufficient weight reduction can be achieved. Further, since both the outer cage and the inner cage are made of plastic, a collision sound or the like when the sprag and the cage collide can be reduced as compared with the conventional example.

[Brief description of the drawings]

FIG. 1 includes a plan view and a sectional view of an embodiment of a one-way clutch of the present invention.

FIG. 2 is a diagram showing the results of an expansion / contraction test of the inner cage of the above embodiment.

FIG. 3 is a diagram showing a relationship between a tensile stress and an amount of deformation of an inner cage.

FIG. 4 is a diagram showing sprag states when the one-way clutch is free and locked.

FIG. 5 includes a plan view and a cross-sectional view of a conventional one-way clutch.

FIG. 6 is a diagram showing the results of an expansion / contraction test of the inner retainer of the conventional one-way clutch.

[Explanation of symbols]

1,51 sprag 2,52 inner cage 3,53 outer cage 5,55 ribbon spring 1a, 51a inner part 1b, 51b outer part 2a, 3a, 5a window 2c pillar

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) F16D 41/07

Claims (1)

(57) [Claims] An inner ring and an outer ring are disposed at a predetermined interval in a circumferential direction at a predetermined interval in a circumferential direction between an inclined position for locking the inner ring and the outer ring and an inclined position for unlocking the inner ring and the outer ring. A plurality of sprags that oscillate in one direction, an inner cage that holds an inner portion of the sprag, an outer cage that holds an outer portion of the sprag, and a one-way including a spring that biases the sprag in one direction In the clutch, the outer cage and the inner cage are made of plastic, and the elastic modulus of the plastic used for manufacturing the inner cage is smaller than the elastic modulus of the plastic used for manufacturing the outer cage, and The plastic used for manufacturing the inner cage is released between the pillars of the inner cage due to the difference in the inclination angle between the sprags when the sprag moves from the unlocked position to the locked position. One-way clutch being characterized in that the plastics such as can be absorbed by the strain within the elastic limit of the inner cage maximum deformation amount.