JP2021120586A - Ratchet type one-way clutch - Google Patents

Abstract

To provide a structure capable of preventing a pole from sticking to an outer ring, in a ratchet type one-way clutch constituted by including a pole stored in a space formed by a cutout formed on the outer ring.SOLUTION: At a part of a wall surface which stores a rotation center part 22a out of a cutout 20 of an outer ring 14 for storing a pole 22, a planar shape part 28 capable of coming into contact with the rotation center part 22a is formed, thereby, when the rotation center part 22a comes into contact with the planar shape part 28 due to e.g., the change in the rotational speed of the outer ring 14, a reaction force F4 is generated between the rotation center part 22a and the planar shape part 28, and the force in the direction being separated from the outer ring 14 can be imparted to the pole 22. Therefore, sticking of the pole 22 to the outer ring 14 can be prevented.SELECTED DRAWING: Figure 2

Description

The present invention relates to a technique for preventing a decrease in durability of a ratchet type one-way clutch.

Patent Document 1 includes a spring that urges a pole (claw member) toward the inner ring side in a ratchet type one-way clutch, and the spring is generated when the centrifugal force generated at high rotation is larger than the urging force by the spring. A structure is disclosed in which all poles are housed in a space (pocket) that shrinks and is formed in an outer ring.

JP-A-2015-197201 JP-A-2017-110707

By the way, for example, when grease or lubricating oil used for wear countermeasures scatters and adheres to the gap between the pole and the outer ring, the pole sticks to the outer ring due to the action of grease or the like, resulting in poor return of the pole. do. If a load is applied to the one-way clutch in the state where this return failure occurs, the load is applied when all the poles have not returned, so that a large load is applied to the poles that have already returned, which may reduce the durability of the poles. there were. Further, for example, in the transitional period in which the rotation speed of the outer ring decreases, the timing at which the pole is pushed out to the inner ring side is shifted due to the action of grease or lubricating oil adhering to the gap between the pole and the outer ring, so that the rotation speed of the outer ring is increased. When a load is applied to the one-way clutch during the lowering transition period, a large load is applied to the pole already pushed out to the inner ring side, which may reduce the durability of the pole.

The present invention has been made in the background of the above circumstances, and an object of the present invention is to provide a structure capable of preventing a pole from sticking to an outer ring in a ratchet type one-way clutch.

The gist of the first invention is (a) an inner ring arranged around the axis, an outer ring rotatably arranged around the axis, and the inner ring and the outer ring. A ratchet type one-way clutch provided between the ratchet type one-way clutch provided between the inner ring and the outer ring, which allows relative rotation in one direction while preventing relative rotation in the opposite direction. (B) The ratchet The mechanism includes a pole that is accommodated in a space formed by a notch formed in the outer ring and that can rotate toward the inner ring side, a recess formed in the inner ring that can engage with the pole, and the pole. A spring for urging toward the inner ring side is provided. (C) The pole is connected to a rotation center portion which is the rotation center of the pole and the rotation center portion, and is connected to the rotation center portion toward the inner ring side. It is composed of a longitudinal claw portion that engages with the recess by being rotated, and (d) is formed along the shape of the rotation center portion of the pole in the notch and rotates thereof. A part of the wall accommodating the central portion is characterized in that a planar shape portion that can come into contact with the rotating central portion is formed.

According to the ratchet type one-way clutch of the first invention, a planar shape portion that can come into contact with the rotation center portion is formed in a part of the wall that accommodates the rotation center portion in the notch of the outer ring that accommodates the pole. Therefore, when the rotation center portion comes into contact with the planar shape portion due to a change in the rotation speed of the outer ring, a reaction force is generated between the rotation center portion and the planar shape portion, and a force is applied to the pole in the direction away from the outer ring. Can be made to. Therefore, it is possible to prevent the pole from sticking to the outer ring, and as a result, it is possible to prevent the durability of the pole from being lowered due to a large load applied to the specific pole.

It is a figure which shows the whole structure of the ratchet type one-way clutch which is one Example of this invention. It is an enlarged view of the ratchet mechanism of FIG. It is a figure which shows typically the operating state of the ratchet mechanism during engine rotation. It is a figure which shows typically the operating state of the ratchet mechanism in the transitional period when the engine speed decreases. It is a figure which shows typically the operation state of the ratchet mechanism when an engine is stopped.

Hereinafter, examples of the present invention will be described in detail with reference to the drawings. In the following examples, the drawings are appropriately simplified or deformed, and the dimensional ratios and shapes of each part are not necessarily drawn accurately.

FIG. 1 shows the overall structure of a ratchet type one-way clutch 10 (hereinafter, one-way clutch 10) according to an embodiment of the present invention. The one-way clutch 10 is provided on the crankshaft of an engine (not shown) and is used for the purpose of preventing reverse rotation of the crankshaft.

The one-way clutch 10 includes a disk-shaped inner ring 12 arranged around the axis C, and a disk-shaped outer ring 14 rotatably arranged around the same axis C as the inner ring 12. A plurality of ratchet mechanisms 16 provided between the inner ring 12 and the outer ring 14 to allow relative rotation in one direction between the inner ring 12 and the outer ring 14 while preventing relative rotation in the opposite direction. It is configured to prepare.

The inner ring 12 is formed in a disk shape by pressing a flat plate having a predetermined thickness. The inner ring 12 is arranged around the axis C, and its inner peripheral portion is spline-fitted with the non-rotating member 18 to constantly stop the rotation. Further, on the outer peripheral surface of the inner ring 12, recesses 24 that can be engaged with the pole 22 described later of the ratchet mechanism 16 are periodically formed in the circumferential direction.

The outer ring 14 is formed in a disk shape by pressing a flat plate having a predetermined thickness. The outer ring 14 is arranged on the outer peripheral side of the inner ring 12 and is rotatable about the axis C. The outer ring 14 is connected to a crankshaft of an engine (not shown) and is rotated integrally with the engine. The outer ring 14 is assumed to be rotated in the clockwise direction when the engine is rotated.

The ratchet mechanism 16 is provided between the inner ring 12 and the outer ring 14, and has a function of allowing relative rotation between the inner ring 12 and the outer ring 14 in one direction while preventing relative rotation in the opposite direction. ing. A plurality of ratchet mechanisms 16 are provided at equal angular intervals in the circumferential direction.

FIG. 2 is an enlarged view of the ratchet mechanism 16 of FIG. The ratchet mechanism 16 includes a pole 22 housed in a space 21 formed by a notch 20 formed in the inner peripheral portion of the outer ring 14, and a recess 24 formed in the outer peripheral portion of the inner ring 12 and capable of engaging with the pole 22. And a spring 26 that urges the pole 22 toward the inner ring 12 side. The spring 26 is composed of a coil spring, and is attached to the outer ring 14 via a fixing mechanism (not shown) that fixes the spring 26 to the outer ring 14.

The pole 22 is formed in a longitudinal shape and is accommodated in the space 21 formed by the notch 20 of the outer ring 14. The pole 22 is composed of a rotation center portion 22a, which is the rotation center of the pole 22, and a longitudinal claw portion 22b connected to the rotation center portion 22a.

The rotation center portion 22a is formed in a substantially circular shape. The pole 22 is rotatable toward the inner ring 12 side around the rotation center 22a. The claw portion 22b is formed in a longitudinal shape, and the claw portion 22b is rotated toward the inner ring 12 side so that the tip portion thereof is engaged with the recess 24 of the inner ring 12. Further, a spring 26 fixed to the outer ring 14 is in contact with the tip end side of the claw portion 22b. The spring 26 urges the claw portion 22b of the pole 22 toward the inner ring 12 side. By the urging force of the spring 26, the pole 22 is rotated toward the inner ring 12 side about the rotation center portion 22a.

By the way, in the conventional structure, as shown by the broken line in FIG. 2, the notch of the outer ring 14 is formed along the shape of the rotation center portion 22a. Here, when the grease (or lubricating oil) scattered toward the one-way clutch 10 enters the gap between the pole 22 and the notch 20 and adheres, the pole 22 sticks to the wall surface of the notch 20 due to the action of the grease. The pole 22 does not return. A poor return of the pole 22 occurs. If a load is applied to the one-way clutch 10 in this state, a large load is applied to the pole 22 in which the return failure has not occurred, which may reduce the durability of the pole 22. Further, in the transitional period in which the engine speed decreases, the grease (or lubricating oil) adhering between the pole 22 and the notch 20 causes the claw portion 22b of the pole 22 to move to the inner ring 12 side by the urging force of the spring 26. There is a gap in the timing of pushing out. Therefore, when a load is applied to the one-way clutch 10 during the transitional period in which the engine speed is lowered, a large load is applied to the pole 22 engaged with the recess 24 of the inner ring 12 at an early timing, so that the durability of the pole 22 is improved. There was a risk of a decrease.

In order to solve the above-mentioned problem, in the notch 20 formed in the outer ring 14, a part of the wall formed along the shape of the rotation center portion 22a of the pole 22 and accommodating the rotation center portion 22a is provided. , A planar shape portion 28 that can come into contact with the rotation center portion 22a is formed. The planar shape portion 28 has a flat shape and is formed on an inclined surface that is inclined at a predetermined angle with respect to the rotation direction (left-right direction of the paper surface) of the outer ring 14.

Hereinafter, the operation of the ratchet mechanism 16 configured as described above will be described with reference to FIGS. 3 to 5. FIG. 3 schematically shows an operating state of the ratchet mechanism 16 during engine rotation. While the engine is rotating, the outer ring 14 is rotated in the clockwise direction (to the right of the paper) together with the engine as shown by the arrow. Similarly, the pole 22 is also rotated clockwise together with the outer ring 14. At this time, the centrifugal force F1 indicated by the white arrow acts on the pole 22. The centrifugal force F1 is perpendicular to the direction of rotation and acts toward the outer ring 14 side (outward in the radial direction). At this time, the pole 22 is rotated clockwise around the rotation center portion 22a by the centrifugal force F1 against the urging force of the spring 26. Therefore, as shown in FIG. 3, since the entire pole 22 is housed in the space 21 formed by the notch 20, the engagement between the pole 22 and the recess 24 of the inner ring 12 is released.

FIG. 4 schematically shows an operating state of the ratchet mechanism 16 in a transitional period in which the engine rotation speed decreases from the rotating state of the engine shown in FIG. 3 or in a transitional period in which the engine stops. As shown in FIG. 4, an inertial force F2 acting in the rotation direction is generated on the pole 22 by the rotation change of the outer ring 14 accompanying the decrease in the engine rotation speed. By this inertial force F2, the rotation center portion 22a of the pole 22 and the planar shape portion 28 of the notch 20 are brought into contact with each other.

At this time, at the contact portion between the rotation center portion 22a and the planar shape portion 28, a pressing force F3 perpendicular to the planar shape portion 28 acts on the outer ring 14, and the pressing force F3 is the same as the pressing force F3 on the inner ring 12. Now, the reaction force F4, which acts in the opposite direction to the pressing force F3, acts. The reaction force F4 is perpendicular to the planar shape portion 28 and acts in the direction toward the inner ring 12. Due to this reaction force F4, a force in the direction away from the outer ring 14 acts on the pole 22. Therefore, the pole 22 is prevented from sticking to the outer ring 14. Further, in the transitional period in which the engine rotation speed decreases, it is possible to prevent the pole 22 of each ratchet mechanism 16 from being pushed out to the inner ring 12 side by the spring 26. In relation to this, even when a load is applied to the one-way clutch 10 during the transitional period in which the engine rotation speed decreases, the load is applied to each pole 22 substantially evenly, so that the recess 24 of the inner ring 12 is filled with the load at an early timing. It is also prevented that a large load is applied to the engaged pole 22 and the durability of the pole 22 is lowered.

Further, as the engine speed decreases, the centrifugal force F1 acting on the pole 22 decreases. On the other hand, since the decrease speed of the engine rotation speed, that is, the change gradient of the engine rotation speed is substantially constant, the inertial force F2 acting on the pole 22 is substantially constant regardless of the engine rotation speed. That is, the magnitude of the reaction force F4 acting on the pole 22 becomes substantially constant during the transitional period in which the engine speed decreases. Therefore, the magnitude of the force acting in the direction of separating the pole 22 from the outer ring 14 is also substantially constant regardless of the engine rotation speed.

FIG. 5 schematically shows an operating state of the ratchet mechanism 16 when the engine is stopped. When the engine rotation speed becomes equal to or lower than a preset threshold value, the urging force of the spring 26 becomes larger than the centrifugal force F1, and the claw portion 22b of the pole 22 is pressed toward the inner ring 12 side by the urging force of the spring 26. At this time, the pole 22 is rotated counterclockwise around the center of rotation 22a, and the claw portion 22b of the pole 22 is engaged with the recess 24 of the outer ring 14. As a result, the rotation of the outer ring 14 in the counterclockwise direction is prevented.

In this way, during the transitional period in which the engine rotation speed decreases, the pole 22 receives the reaction force F4 generated in the planar shape portion 28, so that a force in the direction away from the outer ring 14 acts on the pole 22, so that the pole 22 is moved. It is prevented from sticking to the wall surface of the notch 20 formed in the outer ring 14. Further, when the engine rotation speed becomes equal to or lower than the threshold value, the pole 22 of each ratchet mechanism 16 is pushed out toward the inner ring 12 side at substantially the same timing. As a result, even when a load is applied to the one-way clutch 10 during the transitional period in which the engine rotation speed decreases, each pole 22 of each ratchet mechanism 16 is pushed out to the inner ring 12 side at substantially the same timing, so that each pole 22 The load is evenly applied to the pole 22 and the durability of the pole 22 is prevented from being lowered.

As described above, according to the present embodiment, of the notch 20 of the outer ring 14 accommodating the pole 22, a part of the wall accommodating the rotation center portion 22a has a planar shape portion capable of contacting the rotation center portion 22a. Since 28 is formed, when the rotation center portion 22a comes into contact with the planar shape portion 28 due to a change in the rotation speed of the outer ring 14, a reaction force F4 is generated between the rotation center portion 22a and the planar shape portion 28. Then, a force in the direction away from the outer ring 14 can be applied to the pole 22. Therefore, it is possible to prevent the pole 22 from sticking to the outer ring 14, and it is possible to prevent the durability of the pole 22 from being lowered due to a large load applied to the specific pole 22.

Although the examples of the present invention have been described in detail with reference to the drawings, the present invention also applies to other aspects.

For example, in the above-described embodiment, the outer ring 14 is connected to the engine so as to be able to transmit power, but the present invention is not necessarily limited to this embodiment. For example, the outer ring 14 may be connected to a rotating member other than the engine so as to be able to transmit power.

Further, in the above-described embodiment, the inner ring 12 is connected to the non-rotating member 18, but the present invention is not necessarily limited to this aspect. For example, the inner ring 12 may be connected to a rotatable rotating member.

It should be noted that the above is only one embodiment, and the present invention can be implemented in a mode in which various changes and improvements are made based on the knowledge of those skilled in the art.

10: Ratchet type one-way clutch 12: Inner ring 14: Outer ring 16: Ratchet mechanism 20: Notch 21: Space 22: Pole 22a: Rotation center 22b: Claw 24: Recess 26: Spring 28: Planar shape C: Axial center

Claims (1)

An inner ring arranged around the axis, an outer ring rotatably arranged around the axis, and one of the inner ring and the outer ring provided between the inner ring and the outer ring. A ratchet type one-way clutch equipped with a ratchet mechanism that allows relative rotation in the direction while blocking relative rotation in the opposite direction.
The ratchet mechanism includes a pole housed in a space formed by a notch formed in the outer ring and rotatable toward the inner ring side, a recess formed in the inner ring and engageable with the pole, and the pole. With a spring that urges the inner ring side,
The pole has a rotation center portion that is the rotation center of the pole, and a longitudinal claw portion that is connected to the rotation center portion and is rotated toward the inner ring side to engage with the recess. And consists of
A planar shape portion of the notch, which is formed along the shape of the rotation center portion of the pole and accommodates the rotation center portion, is formed so as to be in contact with the rotation center portion. A ratchet type one-way clutch that is characterized by being used.

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