JP2001349347A - Two-way clutch - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a roller type two-way clutch capable of preventing the occurrence of damage during loading of high torque. SOLUTION: A cylinder surface 2 is formed on the inner periphery of an external member 1, a cam surface 12 is formed on the outer periphery of an external member 11 and a roller 21 is incorporated in a wedge-form space formed between the cam surface 12 and the cylinder surface 2. Brake parts 13 each consisting of an arcuate surface are situated at the two ends in a peripheral direction of the cam surface 12 to limit a moving amount along the cam surface 12 of the roller 21 and the bearing pressure of a contact part between the roller 21 and the cam surface 12 during loading of high torque is kept at a constant value and the damage to the contact part is prevented from occurring.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-way clutch for transmitting rotational torque in both forward and reverse directions between an outer member and an inner member.

[0002]

2. Description of the Related Art FIGS. 9 and 10 show a conventionally known two-way clutch. This two-way clutch has a cylindrical surface 41 formed on the inner periphery of an outer member 40 and an inner member 42.
A cam surface 43 formed of a flat surface is provided on the outer periphery of the roller. A roller 44 is incorporated in a wedge-shaped space formed by the cam surface 43 and the cylindrical surface 41, and a retainer 45 incorporated between the two members 40, 42 is provided. Is provided with a pocket 46 for accommodating the roller 44.

In the two-way clutch having the above structure, for example, when the inner member 42 is rotated in the direction of the arrow in FIG. 9, the roller 44 moves toward the narrow portion of the wedge-shaped space, as shown in FIG. The rotation of the inner member 42 is transmitted to the outer member 40 via the roller 44 that locks by engaging with the cylindrical surface 41 and the cam surface 43.

[0004]

In the roller type two-way clutch, since the cam surface 43 formed on the outer periphery of the inner member 42 is a flat surface, the contact between the cam surface 43 and the roller 44 is prevented. Contact between the plane and the curved surface.

For this reason, when a large load is applied to the outer member 40 and a high torque load is applied, the surface pressure between the cam surface 43 and the roller 44 increases, and there is a possibility that an indentation may occur on the cam surface 43.

Further, since the surface pressure between the cam surface 43 and the roller 44 is large, there is also a disadvantage that the torque capacity is small.

SUMMARY OF THE INVENTION An object of the present invention is to provide a roller type two-way clutch in which the surface pressure between a cam surface and a roller is reduced so as to prevent indentation under a high torque load.

[0008]

According to the present invention, a cylindrical surface is formed on one of an inner periphery of an outer member and an outer periphery of an inner member. A cam surface that forms a narrow wedge-shaped space at both ends in the circumferential direction between the outer surface and the outer member; a roller is incorporated in the wedge-shaped space; and the roller is engaged with both the cylindrical surface and the cam surface. In the two-way clutch, which transmits rotational torque between the inner surface and the inner member, the amount of movement of the roller is limited at both ends in the circumferential direction of the cam surface, and the strat angle of the cam surface is maintained at a specified value. That is, a configuration in which a braking unit is provided is adopted.

As described above, when the braking portion for restricting the movement of the roller is provided at both ends in the circumferential direction of the cam surface, the roller moves toward the narrow portion of the wedge-shaped space under a high torque load and hits the braking portion. The strut angle of the cam surface is kept constant by the contact.

[0010] Here, the strut angle means an angle formed by an orthogonal line of a straight line connecting the clutch center and the roller center and the cam surface in a locked state where the roller is engaged with the cylindrical surface and the cam surface. By making the strut angle constant, it is possible to prevent the roller from strongly biting into the cylindrical surface and the cam surface, and to prevent indentation on the cam surface.

Further, by receiving the roller at the braking portion, the load during torque transmission can be received at the contact portion between the roller and the cam surface and at the contact portion between the roller and the braking portion. become. Therefore, the surface pressure generated between the roller and the cam surface is reduced, and the torque capacity of the two-way clutch can be increased.

The braking portion may be formed of an inclined surface or may be formed of an arcuate surface. The braking portion is formed by an arcuate surface, and the curvature of the arcuate surface is made substantially coincident with the curvature of the outer periphery of the roller, so that the surface pressure generated between the roller and the cam surface can be reduced, and the torque capacity of the two-way clutch can be reduced. Can be further increased.

The strut angle can be set depending on the position of the braking portion, and when the strat angle is small,
Although the roller is easy to lock, the surface pressure increases and the torque capacity decreases. When the strut angle is set to 4.5 ° or more, the roller slides on the cylindrical surface when a high torque load is applied, and a torque limiter function is added to the two-way clutch. Can be prevented.

In the two-way clutch according to the present invention,
The cam surface may be a flat surface or an arcuate surface that curves in a direction along the outer periphery of the roller. When the cam surface is an arcuate surface, the contact area between the roller and the cam surface is increased, so that the surface pressure between the roller and the cam surface can be reduced, and damage to the contact portion between the roller and the cam surface can be more effectively prevented. Second, the torque capacity of the two-way clutch can be increased.

Here, by forming the roller from a steel material such as SUJ2 and performing a hardening treatment such as a carbonitriding treatment to increase the hardness, it is possible to suppress the abrasion due to the sliding of the roller. In this case, it is preferable that the outer member and the inner member are also subjected to a hardening treatment such as carbonitriding to increase the hardness of the cylindrical surface and the cam surface.

[Detailed Description of the Invention] An embodiment of the present invention will be described below with reference to FIGS. FIG. 1 shows a first embodiment of a two-way clutch according to the present invention. This two-way clutch includes an outer member 1, an inner member 11, rollers 21, and a retainer 31, similarly to the above-described conventional two-way clutch.

A cylindrical surface 2 is formed on the inner periphery of the outer member 1, while a plurality of cam surfaces 12 are provided on the outer periphery of the inner member 11 at equal intervals in the circumferential direction.

The cam surface 12 is formed of a flat surface and forms a wedge-shaped space narrowing toward both ends in the circumferential direction between the cam surface 12 and the cylindrical surface 2. The roller 21 is incorporated in each wedge-shaped space. .

The retainer 31 is incorporated between the outer member 1 and the inner member 2. The retainer 31 has a pocket 32 for accommodating the roller 21 at a position facing the cam surface 12.
Is provided.

A cam surface 12 formed on the inner member 11
At both ends in the circumferential direction are provided brake units 13 for limiting the amount of movement of the roller 21. The braking portion 13 is formed of an arcuate surface, and its curvature substantially matches the curvature of the outer periphery of the roller 21.

Now, when the inner member 11 is rotated in the direction of the arrow in FIG. 1, the roller 21 is engaged with each of the cam surface 12 and the cylindrical surface 2 and locked, and the rotation of the inner member 11 is performed via the roller 21. It is transmitted to the outer member 1.

When a large load acts on the outer member 1 when transmitting torque for locking the roller 21, the roller 21 moves toward the narrow portion of the wedge-shaped space and impinges on the braking portion 13 as shown in FIG. Touch The contact makes the strut angle α ₁ of the cam surface 12 constant.

By keeping the strut angle α ₁ constant, it is possible to prevent the roller 21 from strongly biting between the cylindrical surface 2 and the cam surface 12. For this reason, the generation of an indentation on the cam surface 12 is prevented.

Further, as described above, since the roller 21 is received by the braking unit 13, the roller 21 can be received on an arcuate surface having almost the same curvature.
, The torque capacity of the two-way clutch can be increased.

The strut angle α ₁ shown in FIG. Its strat angle α ₁ is 4.5
If it is less than or equal to °, the surface pressure at the contact portion between the roller 21 and the braking portion 13 increases under a high torque load, and there is a possibility that an indentation may occur at the contact portion.

Therefore, in the embodiment, the strut angle α ₁ is set to 4.5 ° or more. With this setting, the slip component of the roller 21 increases, and the roller 21 slides on the cylindrical surface 2 when a high torque load is applied, thereby exhibiting a torque limiter function. For this reason, the surface pressure of the contact portion between the roller 21 and the braking portion 13 can be kept constant, and the impression at the contact portion can be prevented.

Here, when the hardness of the roller 21 is low, the roller 21 is worn due to sliding on the cylindrical surface 2. In order to suppress the abrasion, the roller 21 is subjected to a hardening process such as a carbonitriding process to increase the hardness.

It is preferable that the hardening treatment such as the carbonitriding treatment described above is applied to each of the outer member 1 and the inner member 11 to increase the hardness of the cylindrical surface 2 and the cam surface 12.

When the inner member 11 shown in FIG. 1 is rotated in a direction opposite to the direction of the arrow, the roller 21 is locked by being engaged with the cylindrical surface 2 and the cam surface 12 so that the rotation of the inner member 11 is stopped. The roller 21 is transmitted to the outer member 1 and at the time of a high torque load, so that the roller 21 abuts on the braking portion 13 to prevent the roller 21 from strongly biting the cylindrical surface 2 and the cam surface 12.

FIGS. 3 (I) and 3 (II) show two embodiments according to the present invention.
2 shows a second embodiment of a directional clutch. In this two-way clutch, a cylindrical surface 14 is formed on the outer periphery of the inner member 11, and a cam surface 3 is provided on the inner periphery of the outer member 1. The cam surface 3 has two inclined surfaces 3a, 3 inclined in opposite directions.
b, and a braking portion 4 formed of an arcuate surface is provided at an end of each of the inclined surfaces 3a and 3b.

In the above two-way clutch, the inner member 1
When the roller 1 rotates in the direction of the arrow in FIG. 3 (I), as shown in FIG. 3 (II), the roller 21 bites into the cylindrical surface 14 and one of the inclined surfaces 3a of the cam surface 3 to be locked. The rotation of 11 is transmitted to the outer member 1 via the roller 21. If the load on the outer member 1 is large, the roller 21 is supported by the brake unit 4, strut angle alpha ₂ is kept constant by the support. This strat angle α ₂ is 4.5 as described above.
° or more, the roller 21 slides on the cylindrical surface 14 at the time of a high torque load, and exhibits a function as a torque limiter.

Also in the second embodiment, the surface pressure of the contact portion between the roller 21 and the braking portion 4 at the time of high torque load can be kept constant, and breakage at the contact portion can be prevented.

FIGS. 4 (I) and 4 (II) show two embodiments according to the present invention.
9 shows a third embodiment of a directional clutch. The third embodiment differs from the first embodiment shown in FIGS. 1 and 2 only in the shape of the cam surface formed on the inner member 11. That is, the cam surface 15 formed on the outer periphery of the inner member 11 is an arc-shaped surface that curves in a direction along the outer periphery of the roller 21.

As described above, when the cam surface 15 is formed into an arcuate surface, the surface pressure of the contact portion between the cam surface 15 and the roller 21 during torque transmission between the outer member 1 and the inner member 11 can be reduced. Thus, the torque capacity of the two-way clutch can be increased.

FIGS. 5 (I) and 5 (II) show two embodiments according to the present invention.
9 shows a fourth embodiment of a directional clutch. The fourth embodiment and the second embodiment shown in FIG.
The only difference is the shape of the cam surface formed in the above. In the fourth embodiment, the cam surface 5 formed on the inner periphery of the outer member 1 is formed by an arcuate surface.

As described above, by making the cam surface 5 an arc-shaped surface, the surface pressure at the contact portion between the roller 21 and the cam surface 5 can be reduced as in the two-way clutch shown in FIG. The torque capacity of the two-way clutch can be increased.

In the two-way clutch shown in FIGS.
Since the side surfaces of the pockets 32 formed in the retainer 31 that face each other in the circumferential direction are flat surfaces and the interval between the side surfaces is larger than the outer diameter of the roller 21, the outer member 1 and the inner member 1
When the retainer 31 is assembled between the two, the roller 21 placed in the pocket 32 falls off, and it cannot be said that the assemblability is good. In order to improve the assemblability, in the two-way clutch shown in FIG. 6, a pair of side faces 33 facing each other in the circumferential direction of a pocket 32 formed in a retainer 31 are protruded inward at an inner diameter end and an outer diameter side end. The protrusions 34 are formed such that the distance between the circumferentially opposed protrusions 34 is smaller than the outer diameter of the roller 21 to prevent the roller 21 from dropping out of the pocket 32.

In the two-way clutch shown in FIGS. 7 and 8, retaining rings 35 and 36 are fitted on the outer and inner diameter surfaces of the retainer 31, and the retainers 31 and 36 are respectively fitted to the retaining rings 35 and 36. Pillar portion 37 formed between pockets 32
The retaining pieces 38 overlapping the outer surface and the inner surface are formed at intervals in the circumferential direction, and the retaining pieces 3 opposed in the circumferential direction are formed.
The distance between the rollers 8 is made smaller than the outer diameter of the roller 21 to prevent the roller 21 from falling off the pocket 32.

[0039]

As described above, according to the present invention, the braking portions are provided at both ends in the circumferential direction of the cam surface, and the movement of the roller along the cam surface is restricted by the braking portions. The strut angle between the rollers is kept constant, so that the roller can be prevented from biting into the cam surface under a high torque load, and indentation or damage at the contact portion between the roller and the cam surface can be prevented. Can be.

Further, by setting the strut angle between the roller and the cam surface to be equal to or more than 4.5 °, when a high torque load is applied during transmission of the rotational torque between the outer member and the inner member, the cylindrical shape is reduced. The roller can be slid along the surface, and the impression or damage at the contact portion between the roller and the cam surface can be more effectively prevented.

Further, by making the braking portion an arc surface and making the curvature of the arc surface substantially coincide with the curvature of the outer periphery of the roller, the surface pressure of the contact portion between the roller and the cam surface can be further reduced. The torque capacity of the clutch can be increased.

Further, by forming the cam surface as an arcuate surface curved in a direction along the outer periphery of the roller, the contact pressure between the roller and the cam surface can be reduced.
The torque capacity of the directional clutch can be increased.

[Brief description of the drawings]

FIG. 1 is a sectional view showing a first embodiment of a two-way clutch according to the present invention.

FIG. 2 is a sectional view showing a state of the two-way clutch shown in FIG. 1 during torque transmission.

FIG. 3 (I) shows a second example of the two-way clutch according to the present invention.
Sectional view showing an embodiment of the present invention, (II) is a sectional view showing a state at the time of torque transmission.

FIG. 4I shows a third example of the two-way clutch according to the present invention;
Sectional view showing an embodiment of the present invention, (II) is a sectional view showing a state at the time of torque transmission.

FIG. 5 (I) is a fourth example of the two-way clutch according to the present invention.
Sectional view showing an embodiment of the present invention, (II) is a sectional view showing a state at the time of torque transmission.

FIG. 6 is a sectional view showing another example of the two-way clutch retainer according to the present invention.

FIG. 7 is a sectional view showing still another example of the retainer of the two-way clutch according to the present invention.

FIG. 8 is a plan view of the cage shown in FIG. 7;

FIG. 9 is a sectional view showing a conventional two-way clutch.

FIG. 10 is a sectional view showing a state of the two-way clutch shown in FIG. 9 during torque transmission.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Outer member 2 Cylindrical surface 3 Cam surface 4 Braking part 5 Cam surface 11 Inner member 12 Cam surface 13 Braking part 14 Cylindrical surface 15 Cam surface 16 Cam surface 21 Roller

Claims (7)

[Claims] 1. A cam having a cylindrical surface formed on one of an inner periphery of an outer member and an outer periphery of an inner member, and having a narrow wedge-shaped space at both ends in the circumferential direction with the other cylindrical surface. A two-way clutch in which a roller is incorporated into the wedge-shaped space, and the roller is engaged with both the cylindrical surface and the cam surface to transmit a rotational torque between the outer member and the inner member. 2. The two-way clutch according to claim 1, further comprising a braking unit provided at both ends in the circumferential direction of the cam surface to limit the amount of movement of the roller and maintain the strut angle of the cam surface at a specified value. 2. The two-way clutch according to claim 1, wherein the specified value is 4.5 ° or more. 3. The two-way clutch according to claim 1, wherein said braking portion comprises an arc surface. 4. The two-way clutch according to claim 3, wherein the curvature of the arc surface substantially matches the curvature of the outer periphery of the roller. 5. The two-way clutch according to claim 1, wherein said cam surface comprises a flat surface. 6. The two-way clutch according to claim 1, wherein said cam surface comprises an arc surface curved in a direction along the outer periphery of the roller. 7. The two-way clutch according to claim 1, wherein at least one of the outer member, the inner member, and the roller is carbonitrided.