JP6939539B2 - One-way clutch - Google Patents

Description

The present disclosure relates to a one-way clutch, and more particularly to a one-way clutch applicable to an overrunning clutch of a vehicle starter.

The vehicle is equipped with a starter to start the internal combustion engine mounted on the vehicle. The starter transmits torque to the internal combustion engine when the internal combustion engine is started, but needs to cut off the torque from the internal combustion engine immediately after the internal combustion engine is started. Therefore, the starter is provided with an overrunning clutch, that is, a one-way clutch, which allows only torque transmission from the starter side to the internal combustion engine side and prohibits torque transmission in the reverse direction.

Generally, a one-way clutch has a wedge-shaped space formed between an inner ring and an outer ring and the distance in the radial direction becomes narrower toward one side in the circumferential direction, a roller housed in the wedge-shaped space, and a roller on one side in the circumferential direction. It is provided with an elastic member to be urged.

Japanese Unexamined Patent Publication No. 2001-200862 Japanese Unexamined Patent Publication No. 2011-179612

By the way, since the outer ring is generally formed by cold forging, the inner peripheral surface thereof is provided with a draft in the axial direction for pulling out the convex shape. The same applies to the inner peripheral surface of the outer ring forming the wedge-shaped space. Therefore, the radial spacing of the wedge-shaped space gradually increases from one end side to the other end side in the axial direction.

However, since the outer diameter of the roller is constant, when the one-way clutch is locked, stress is concentrated on the contact part between the end on one end side in the axial direction of the roller and the inner surface of the wedge-shaped space, and this stress concentration causes surface peeling and cracking. There is a risk of damage such as.

Therefore, the present disclosure was devised in view of such circumstances, and an object thereof is to provide a one-way clutch capable of suppressing stress concentration at the time of locking.

According to one aspect of the present disclosure
Inner ring and
An outer ring arranged coaxially with the inner ring and
A wedge-shaped space formed between the inner ring and the outer ring, in which the distance in the radial direction becomes narrower toward one side in the circumferential direction.
A roller housed in the wedge-shaped space and capable of rolling in the circumferential direction,
An urging means for urging the roller to one side in the circumferential direction,
With
The inner peripheral surface of the outer ring forming the wedge-shaped space has an axial draft.
The draft is a draft that gradually increases the diameter of the inner peripheral surface of the outer ring from one end side to the other end side in the axial direction.
A one-way clutch is provided in which the roller has a roller hole extending in the axial direction from an end surface on one end side in the axial direction.

Preferably, the roller hole has a length shorter than the total length of the roller.

The roller hole may have a length equal to the total length of the roller.

The roller hole may have a tapered portion whose hole diameter changes in the axial direction contrary to the draft.

Preferably, the roller hole is provided coaxially with the center of the roller.

Preferably, the roller has a constant outer diameter in the axial direction.

Preferably, the one-way clutch is configured to be applied to the overrunning clutch of the vehicle starter.

According to the present disclosure, stress concentration at the time of locking can be suppressed.

It is a schematic block diagram of a starter and its surroundings. It is a cross-sectional view of a main part of a one-way clutch, (A) shows when it is locked, and (B) shows when it is unlocked. It is a conceptual diagram which shows the stress distribution when a general roller is used. The rollers of this embodiment are shown, (A) is a front sectional view, and (B) is an end view. It is a conceptual diagram which shows the stress distribution when the roller of this embodiment is used. The rollers of the first modification are shown, (A) is a front sectional view, and (B) is an end view. The rollers of the second modification are shown, (A) is a front sectional view, and (B) is an end view. The rollers of the third modification are shown, (A) is a front sectional view, and (B) is an end view. The rollers of the fourth modification are shown, (A) is a front sectional view, and (B) is an end view.

Hereinafter, embodiments of the present disclosure will be described with reference to the accompanying drawings. It should be noted that the present disclosure is not limited to the following embodiments.

FIG. 1 is a schematic configuration diagram of a starter to which the one-way clutch of the present embodiment is applied and its surroundings. The starter ST is mounted on the vehicle in order to start an internal combustion engine (engine) mounted on the vehicle (not shown). The one-way clutch CL of the present embodiment is configured to be applied to the overrunning clutch of the starter ST. The type and application of the vehicle and the internal combustion engine are not particularly limited, but the vehicle may be a large vehicle such as a truck, and the internal combustion engine may be a diesel engine.

The starter ST includes an electric motor 1, a main contact 2, a plunger 3, a holding coil 4, a suction coil 5, a return spring 6, a rotating lever 7, a one-way clutch CL, and a pinion shaft 8. The starter ST is powered by the vehicle-mounted battery 9 and is turned on and off by turning the starter switch 10 on and off. When the starter ST is turned on, the pinion shaft 8 engages with the ring gear 11 of the engine as shown by an arrow in the figure, and at the same time, the motor 1 is turned on to rotationally drive the pinion shaft 8 and the ring gear 11. Since the ring gear 11 is connected to the crankshaft of the engine, the crankshaft is rotationally driven by this, and the engine is started.

FIG. 1 shows a state in which the starter ST is off. At this time, the plunger 3 is urged to the off position on the right side in the drawing by the return spring 6. Further, the pinion shaft 8 is located at an off position on the left side in the drawing which does not mesh with the ring gear 11. The pinion shaft 8 integrally includes a shaft body 12 and a pinion gear 13. By engaging the shaft body 12 with the inner ring 21 which is the output unit of the one-way clutch CL by the spline 14, the pinion shaft 8 can slide and move in the axial direction (left-right direction in the figure) with respect to the inner ring 21 of the one-way clutch CL. Is.

A pinion gear 16 is provided at the tip of the output shaft 15 of the motor 1, and the pinion gear 16 is always meshed with the outer gear 17. The outer gear 17 is formed on the outer peripheral surface of the outer ring 22 which is the input portion of the one-way clutch CL.

The rotation lever 7 rotates around the lever center 18 in conjunction with the axial (left-right direction) movement of the plunger 3. The rotary lever 7 transmits the axial movement of the plunger 3 to the pinion shaft 8 to move the pinion shaft 8 in the axial direction.

Next, the operation of the starter ST will be described. When the starter switch 10 is turned on, the current from the battery 9 flows through the holding coil 4 to reach ground E. At this time, a magnetic field is generated by the current flowing through the holding coil 4 and the suction coil 5 wound around the plunger 3, and an electromagnetic force, that is, a driving force is generated to move the plunger 3 to the left side in the drawing as shown by the arrow.

Due to this driving force, the plunger 3 moves axially to the left side in the drawing. This axial movement causes the rotation lever 7 to rotate counterclockwise as indicated by an arrow, and this rotation slides the pinion shaft 8 to the right side in the drawing as indicated by an arrow.

At the same time, the motor 1 is slowly rotated by a relatively small current that reaches the motor 1 and the earth E via the suction coil 5.

At the same time that the pinion shaft 8 engages with the ring gear 11 as shown by the virtual line, the plunger 3 closes the main contact 2 as shown by the virtual line. The positions of the pinion shaft 8 and the plunger 3 at this time are referred to as on positions. As a result, the motor 1 is directly connected to the battery 9, a large current flows through the motor 1, and the motor 1 is strongly rotationally driven.

The rotation of the motor 1 is sequentially transmitted to the pinion gear 16, the one-way clutch CL, the pinion shaft 8, and the ring gear 11. As a result, the crankshaft is rotationally driven and the engine is started.

At this stage, since the inlet and outlet of the suction coil 5 have the same potential, no current flows through the suction coil 5. Therefore, the driving force of the plunger 3 by the suction coil 5 disappears, but since the plunger 3 has already moved and only needs to hold the position after that, the position of the plunger 3 is held by the driving force of the holding coil 4. ..

Next, when the start of the engine is completed and the starter switch 10 is turned off, the process is as follows. At the moment when the starter switch 10 is turned off, the main contact 2 is still closed. Therefore, a current flowing from the battery 9 to the suction coil 5 and the holding coil 4 is instantaneously generated.

Then, since the electromagnetic forces of both coils cancel each other out, the driving force of both coils to the plunger 3 is substantially eliminated, and the plunger 3 is returned to the off position on the right side by the return spring 6. Then, in the reverse movement of the above, the pinion shaft 8 is pulled out from the ring gear 11 to the left side, and at the same time, the motor 1 is stopped and the starter ST is turned off.

In the one-way clutch CL, when the motor 1 is turned on while the engine is starting, the outer ring 22 and the inner ring 21 are integrated, that is, locked, and the rotation of the pinion gear 16 is transmitted to the pinion shaft 8. On the other hand, when the pinion shaft 8 is driven from the engine side after the engine start is completed (after the engine is started), the outer ring 22 and the inner ring 21 are separated, and the rotation of the pinion shaft 8 is not transmitted to the pinion gear 16. The rotation of the motor 1 by the engine is prevented. The structure of the one-way clutch CL that performs such an operation will be described below.

The one-way clutch CL has the above-mentioned inner ring 21 and outer ring 22. The inner ring 21 and the outer ring 22 are arranged coaxially with the clutch central axis C, coaxially with each other, and relatively rotatable around the axis. The outer ring 22 is rotatably fitted to the outer side in the radial direction of the inner ring 21. However, the axial movement of the outer ring 22 with respect to the inner ring 21 is regulated by a stopper (not shown). Further, the axial movement of the outer ring 22 with respect to the starter body is also regulated by a stopper (not shown), and the one-way clutch CL is held at a fixed position. A spline hole 23 penetrating in the axial direction is provided in the central portion of the inner ring 21, and the spline 14 of the pinion shaft 8 is inserted and engaged so as to be slidable in the axial direction.

As shown in detail in FIG. 2A, a wedge-shaped space 24 is formed between the inner ring 21 and the outer ring 22. The wedge-shaped space 24 is a space in which the distance in the radial direction becomes narrower toward one side in the circumferential direction, that is, the lock side. A plurality of wedge-shaped spaces 24 are formed at equal intervals in the circumferential direction of the outer ring 22.

The outer peripheral surface 25 of the inner ring 21 is simply a cylindrical surface having a constant radius in the circumferential direction and the axial direction. On the other hand, the inner peripheral surface 26 of the outer ring 22 has a recess 27 recessed outward in the radial direction at the position where the wedge-shaped space 24 is formed. The bottom surface of the recess facing the inner ring outer peripheral surface 25 forms a cam surface 28, and the radial distance between the cam surface 28 and the inner ring outer peripheral surface 25 becomes narrower toward the lock side. For example, the distance D1 at the predetermined position on the lock side in the drawing is narrower than the distance D2 at the predetermined position on the other side in the circumferential direction, that is, the unlock side. Therefore, the cam surface 28 is not parallel to the inner ring outer peripheral surface 25, and is inclined so that the lock side is closer to the inner ring outer peripheral surface 25 than the unlock side. In this way, the wedge-shaped space 24 is defined by the cam surface 28 and the inner ring outer peripheral surface 25.

A roller 30 is housed in each wedge-shaped space 24 so as to be rotatable in the circumferential direction. The roller 30 is extended in the axial direction and has a circular cross section.

Further, in each wedge-shaped space 24, an elastic member as an urging means for urging the roller 30 to the lock side, specifically, a coil spring 31 is also housed. That is, a spring chamber 32 is formed at the unlocked end of the recess 27, and the coil spring 31 is arranged in the spring chamber 32 in a compressed state adjacent to the roller 30 and in a posture along the circumferential direction. ing. Therefore, the coil spring 31 functions as a push spring that pushes the roller 30 toward the lock side as shown by an arrow in FIG. 2 (A).

When the motor 1 is turned on while the engine is starting, the outer ring 22 receives the rotational torque in the rotational direction R from the pinion gear 16. This rotation direction R is a direction from the lock side to the unlock side. When the outer ring 22 receives the rotational torque, the outer ring 22 rotates in the rotation direction R, and this rotation causes a relative rotation that rotates the outer ring 22 in the rotation direction R with respect to the roller 30 pushed to the lock side by the coil spring 31. Cause for a moment. Due to this relative rotation, the roller 30 moves relatively to the lock side in the wedge-shaped space 24, and is firmly sandwiched between the cam surface 28 and the inner ring outer peripheral surface 25. As a result, the outer ring 22 and the inner ring 21 are locked, the rotational torque of the outer ring 22 is transmitted to the inner ring 21, and the outer ring 22 and the inner ring 21 rotate together.

On the other hand, as shown in FIG. 2B, immediately after the engine start is completed, the pinion shaft 8 and the inner ring 21 are reversely driven from the engine side. At this time, the inner ring 21 rotates in the rotation direction R at a higher rotation speed than the outer ring 22. Therefore, the inner ring 21 moves the roller 30 relatively to the unlock side in the wedge-shaped space 24 as shown by the arrow, and unlocks the outer ring 22 and the inner ring 21 by the roller 30. As a result, the inner ring 21 and the outer ring 22 become free from each other, and the transmission of rotational torque between the inner ring 21 and the outer ring 22 is eliminated.

In this way, when the outer ring 22 tries to rotate at a rotation speed higher than that of the inner ring 21 in the rotation direction R, the outer ring 22 and the inner ring 21 are locked, and the rotational torque of the outer ring 22 is transmitted to the inner ring 21. On the other hand, when the inner ring 21 tries to rotate at a rotation speed higher than that of the outer ring 22, the outer ring 22 and the inner ring 21 are unlocked, and the rotational torque is not transmitted between the outer ring 22 and the inner ring 21.

As shown in FIG. 1, both ends of the wedge-shaped space 24 in the axial direction are closed by appropriate means to prevent the rollers 30 and the coil spring 31 from falling off. In the present embodiment, the end wall 33 of the outer ring 22 is formed on one end side in the axial direction (right side in the drawing), whereby one end in the axial direction of the wedge-shaped space 24 is closed. Further, a lid plate 34 is attached to the other end side in the axial direction (left side in the drawing), whereby the other end in the axial direction of the wedge-shaped space 24 is closed.

By the way, such a one-way clutch CL has the following problems.

The outer ring 22 is formed by forging, particularly cold forging, and the inner peripheral surface 26 thereof is formed by a convex shape. Therefore, the inner peripheral surface 26 is provided with a very slight draft (for example, about 0.5 to 2 °) in the axial direction in order to pull out the convex shape. The inner peripheral surface of the outer ring 22 forming the wedge-shaped space 24, specifically, the cam surface 28 is similarly provided with a draft in the axial direction. Therefore, the radial interval of the wedge-shaped space 24 gradually increases from one end side to the other end side in the axial direction. In the case of the present embodiment, as shown in FIG. 1, the outer ring 22 is open on the other end side in the axial direction (left side in the drawing) of the wedge-shaped space 24, and the other end side in the axial direction is the die cutting direction. The roller 30 and the coil spring 31 are inserted into the wedge-shaped space 24 from the other end side in the axial direction. The inner diameter of the cam surface 28 and the radial distance of the wedge-shaped space 24 gradually increase toward the other end side in the axial direction. Therefore, when viewed from the other end side in the axial direction, the wedge-shaped space 24 seems to have a narrow radial interval on the back side. As described above, the outer diameter of the outer peripheral surface 25 of the inner ring 21 is constant in the circumferential direction and the axial direction.

As shown in FIG. 3, it is assumed that a general roller 30A having a constant outer diameter and a solid shape is housed in the wedge-shaped space 24 (referred to as a comparative example). In this case, when the one-way clutch is locked, the corner portion of the one end side (right side in the drawing) of the roller 30A bites into the inner surface of the wedge-shaped space 24, that is, the cam surface 28, and stress is concentrated on the contact portion between the two. do. Due to this stress concentration, at least one of the roller 30A and the cam surface 28 may be damaged such as surface peeling or cracks.

Therefore, in the present embodiment, in order to solve such a problem, as shown in FIGS. 4 and 5, a roller 30 having a roller hole 36 inside is used. The right side of FIGS. 4A and 5 is the one end side in the axial direction, the left side is the other end side in the axial direction, and FIG. 4B is an end view when viewed from one end side in the axial direction. The roller hole 36 extends axially from the end surface 37 on one end side in the axial direction toward the other end side in the axial direction. The cross-sectional shape of the roller hole 36 is circular.

The roller hole 36 has a length L2 shorter than the total length L1 of the roller 30. In other words, the roller hole 36 is a non-through hole that does not penetrate in the axial direction of the roller 30. Therefore, the roller 30 has a partially hollow structure. The length L2 of the roller hole 36 is preferably longer than half the length ((1/2) L) of the total roller length L1 as shown in the illustrated example. However, the length L2 of the roller hole 36 may be equal to or shorter than half the length of the roller total length L1.

The roller hole 36 is provided at the center of the roller 30 coaxially with the central axis CR of the roller 30. The outer diameter D of the roller 30 is constant as in the general roller 30A described above.

The roller hole 36 has a tapered portion 38 whose hole diameter d changes in the axial direction. The hole diameter d of the tapered portion 38 changes in the axial direction contrary to the draft gradient θ of the outer ring 22 as shown in FIG. That is, according to the draft gradient θ, the inner diameter of the outer ring 22 increases from one end side in the axial direction toward the other end side, but according to the tapered portion 38, the hole diameter d is from the other end side in the axial direction. It gets bigger toward one end. In the case of this embodiment, the hole diameter d of the roller hole 36 changes over the entire length of the roller hole 36. Therefore, the roller hole 36 has a tapered portion 38 over its entire length. The taper angle of the tapered portion 38 is β. As a result of the taper converging at the other end of the roller hole 36 in the axial direction, the roller hole 36 has a tapered triangular cross-sectional shape as shown in FIG. 4 (A).

In the present embodiment, the taper angle β is set to be slightly larger than the draft gradient θ. Its advantages will be described later.

According to the present embodiment, as shown in FIG. 5, when the corner portion of the one end side (right side in the drawing) of the roller 30 in the axial direction is pressed against the cam surface 28 when the one-way clutch is locked, the roller 30 It can be elastically compressed and deformed by crushing it in the radial direction so that one end side in the axial direction of the is slightly elliptical in cross section. That is, since there is a roller hole 36 which is a hollow portion on one end side in the axial direction of the roller 30, it is possible to reduce the radial rigidity of the roller 30 and elastically compress and deform it when pressed. Therefore, the roller 30 comes into contact with the cam surface 28 in a wider area, and the stress can be dispersed and equalized at the contact portion. Therefore, stress concentration at the time of locking can be suppressed, and damage to the rollers 30 and the like can be reliably suppressed. And at the same time as increasing the durability, the transmission torque can be increased. Since stress concentration is suppressed, the required performance can be guaranteed even if the clutch is miniaturized.

The lower figures of FIGS. 3 and 5 show the contact area b with the cam surface 28 when the rollers 30a and 30 are viewed from the direction of the arrow a. As can be seen by comparing these figures, the present embodiment can increase the contact area and suppress the stress concentration as compared with the comparative example.

By the way, if the roller hole 36 is provided, the rigidity of the roller 30 is lowered. However, in the present embodiment, the length L2 of the roller hole 36 is shorter than the total length L1 of the roller 30, in short, one end side in the axial direction of the roller 30. Is partially provided with a roller hole 36. Therefore, it is possible to optimally balance ensuring the rigidity of the roller 30 and suppressing stress concentration, and to achieve both.

In the present embodiment, since the roller hole 36 is provided coaxially with the central portion of the roller 30, the roller hole 36 can be easily machined and the rotation balance of the roller 30 can be well secured. Further, the roller 30 can be compressed and deformed in the same manner regardless of the position in which the roller 30 is pressed in the circumferential direction.

Further, in the present embodiment, since the roller 30 has a constant outer diameter D in the axial direction, the roller 30 of the present embodiment can be manufactured by using the existing general roller 30A, and the manufacturing cost can be reduced.

Further, in the present embodiment, since the roller hole 36 has the tapered portion 38, there are the following advantages. Due to the presence of the draft θ, the radial spacing of the wedge-shaped space 24 gradually decreases toward one end in the axial direction. Therefore, the pressing force against the roller 30 becomes stronger toward one end side in the axial direction of the wedge-shaped space 24. According to the present embodiment, the tapered portion 38 increases the hole diameter d of the roller hole 36 toward one end side in the axial direction. Therefore, as the pressing force becomes stronger, the hole diameter d can be increased, the amount of compression deformation of the roller 30 can be increased, and the roller 30 can be appropriately compression-deformed according to the shape change of the wedge-shaped space 24. Then, the stress concentration at the contact portion of the roller 30 can be optimally suppressed.

By the way, if the taper angle β is equal to the draft gradient θ, the taper angle β becomes equal to the taper angle β1 (= θ) of the wedge-shaped space 24 in the cross-sectional view as shown in FIG. In such a case, the rigidity of the roller 30 is too high and the amount of compressive deformation is insufficient, so that stress concentration may not be sufficiently suppressed.

Therefore, in the present embodiment, the taper angle β is set to an angle slightly larger than the draft gradient θ, the rigidity of the roller 30 is slightly lowered to secure a sufficient amount of compressive deformation, and stress concentration can be sufficiently suppressed. ..

However, if the taper angle β is made too large, the rigidity may be excessively lowered, which may cause problems such as shortening the life of the roller 30 and deteriorating the rotational torque transmission performance. Therefore, it is preferable that the taper angle β is an optimum value that can sufficiently suppress stress concentration while satisfying such basic performance.

In the present embodiment, it has been stated that the taper angle β is preferably an angle larger than the draft gradient θ, but in some cases, the taper angle β is preferably an angle equal to or smaller than the draft gradient θ. There can be situations. Therefore, it is desirable that the taper angle β is optimally set to an angle larger than the draft gradient θ, an equal angle, or a smaller angle based on the test results and the like.

Next, some modifications of the present embodiment will be described. The same parts as those in the above-mentioned basic embodiment are designated by the same reference numerals in the drawings, and the description thereof will be omitted. Hereinafter, the differences from the basic embodiment will be mainly described.

(First modification)
In the first modification shown in FIG. 6, the roller hole 36 is a drilled hole machined by a drill or the like, and has a substantially constant inner diameter d. The roller hole 36 is generally cylindrical. However, since the end surface 39 on the other end side of the roller hole 36 in the axial direction is machined by the drill tip surface, it is an extremely short tapered portion 38. Therefore, in a strict sense, the roller hole 36 of this modification also has a tapered portion 38.

According to this modification, since the roller hole 36 can be formed simply by drilling, there is an advantage that the roller hole 36 can be easily produced.

It is optional to provide the tapered portion 38. For example, it is possible to eliminate the tapered portion 38 by processing the end surface 39 on the other end side of the roller hole 36 in the axial direction perpendicular to the roller central axis CR.

(Second modification)
The second modification shown in FIG. 7 is generally a combination of the first modification and the configuration of the basic embodiment. That is, the roller hole 36 of the first modification is formed by using the cylindrical portion of the roller hole 36 of the first modification except for the end surface 39 on the other end side in the axial direction as the tapered portion 38B. For example, the roller hole 36 of the first modification is drilled and then the inner peripheral surface of the hole is tapered to produce the roller hole 36 of the present modification. The roller hole 36 of the present modification can also be easily manufactured because it is only necessary to taper the roller hole 36 of the first modification.

(Third modification example)
In the third modification shown in FIG. 8, the roller hole 36 has a length L2 equal to the total length L1 of the roller 30. In other words, the roller hole 36 is a through hole that penetrates in the axial direction over the entire length of the roller 30. Therefore, the roller 30 has a hollow structure as a whole. The roller hole 36 is, for example, a drilled hole machined by a drill or the like, and has a cylindrical shape having a constant inner diameter d.

This modification has an advantage that the roller hole 36 can be easily produced because the roller hole 36 can be formed by simply forming the through hole by drilling. In particular, when drilling, it is not necessary to stop the machining in the middle of the roller 30 in the axial direction, so that the roller hole 36 can be very easily formed.

Here, if the roller hole 36 is a through hole as in this modification, there is a concern that the rigidity of the roller 30 may decrease. However, if the material of the roller 30 and the hole diameter d of the roller hole 36 are appropriately determined, the rigidity of the roller 30 can be ensured. Therefore, if the rigidity of the roller 30 can be ensured, there is no particular problem even if the roller hole 36 is used as a through hole.

The roller 30 according to the present disclosure suppresses stress concentration by compressing and deforming the roller 30 in the radial direction outside the roller hole 36 in the radial direction. Therefore, it is preferable that there is nothing inside the roller hole 36 that hinders the radial compressive deformation of the roller 30 and the roller hole 36. It is desirable that the inside of the roller hole 36 is merely a space as in each example of the present embodiment.

(Fourth modification)
In the fourth modification shown in FIG. 9, a tapered portion 38 is provided on the entire length of the roller hole 36 as a through hole.

In the case of this modification, the end face 37 having a larger hole diameter d of the roller hole 36 is on one end side in the axial direction, and the end face 41 having a smaller hole diameter d is on the other end side in the axial direction. The orientation of the direction should be specified. However, since the difference in hole diameters on both end faces is small, it is difficult to specify the axial orientation of the roller 30 from the appearance and tactile sensation. Therefore, the identification mark 40 may be provided on the roller 30 so that the orientation in the axial direction can be easily specified. As a result, erroneous assembly of the roller 30 can be prevented.

For example, the identification mark 40 is formed by a recess processed by a punch or the like. The recess is preferably provided on the end surface of the roller 30, particularly on the end surface 41 on the other end side in the axial direction. As a result, the roller 30 can be inserted into the wedge-shaped space 24 from the other end side in the axial direction while looking at the recess, and erroneous assembly can be reliably suppressed.

Although the embodiments of the present disclosure have been described in detail above, the present disclosure may also include the following other embodiments.

(1) For example, the roller hole 36 may have a tapered portion 38 in a part in the axial direction thereof. For example, the tapered portion 38 may be formed in a part of the portion having a constant inner diameter d in the first modification (FIG. 6). In this case, the tapered portion 38 can be formed on one end side in the axial direction of the portion. Similar deformation is possible in the third modification (FIG. 8).

(2) The cross-sectional shape of the roller hole 36 is not limited to a circle, and may be another shape. For example, it may be a triangle, a quadrangle, a polygon having a pentagon or more, an ellipse, a semicircle, a star, or the like.

(3) The outer ring 22 may be manufactured by a manufacturing method other than forging, for example, precision casting.

(4) The urging means is not limited to the coil spring 31, and may be formed by other elastic members such as leaf springs, countersunk springs, and rubber.

(5) The one-way clutch according to the present disclosure can be applied to applications other than vehicle starters.

The configurations of the above-described embodiments and modifications can be combined partially or wholly, unless otherwise inconsistent. The embodiments of the present disclosure are not limited to the above-described embodiments, and all modifications, applications, and equivalents included in the ideas of the present disclosure defined by the claims are included in the present disclosure. Therefore, this disclosure should not be construed in a limited way and may be applied to any other technique that falls within the scope of the ideas of this disclosure.

21 Inner ring 22 Outer ring 24 Wedge-shaped space 28 Cam surface 30 Roller 31 Coil spring 35 Outer surface 36 Roller hole 37 End surface 38 Tapered part CL One-way clutch ST Starter θ Draft

Claims (7)

Inner ring and
An outer ring arranged coaxially with the inner ring and
A wedge-shaped space formed between the inner ring and the outer ring, in which the distance in the radial direction becomes narrower toward one side in the circumferential direction.
A roller housed in the wedge-shaped space and capable of rolling in the circumferential direction,
An urging means for urging the roller to one side in the circumferential direction,
With
The inner peripheral surface of the outer ring forming the wedge-shaped space has an axial draft.
The draft is a draft that gradually increases the diameter of the inner peripheral surface of the outer ring from one end side to the other end side in the axial direction.
A one-way clutch in which the roller has a roller hole extending in the axial direction from an end surface on one end side in the axial direction. The one-way clutch according to claim 1, wherein the roller hole has a length shorter than the total length of the roller. The one-way clutch according to claim 1, wherein the roller hole has a length equal to the total length of the roller. The one-way clutch according to any one of claims 1 to 3, wherein the roller hole has a tapered portion whose hole diameter changes in the axial direction contrary to the draft. The one-way clutch according to any one of claims 1 to 4, wherein the roller hole is provided coaxially with the roller. The one-way clutch according to any one of claims 1 to 5, wherein the roller has a constant outer diameter in the axial direction. The one-way clutch according to any one of claims 1 to 6, which is configured to be applied to an overrunning clutch of a vehicle starter.

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