Search

US-12618441-B2 - Cam clutch

US12618441B2US 12618441 B2US12618441 B2US 12618441B2US-12618441-B2

Abstract

The present invention aims to provide a cam clutch that enables smooth switching between operation modes while preventing the occurrence of cam engagement, and achieves noise reduction and long service life with a simple structure, without upsizing and increasing the number of components. The above problem is solved by providing a transmission member ( 161 ), which comes into contact with each of a first cam ( 131 a ) and a second cam ( 131 b ) that have different engaging directions, to be rotatable and movable in the axial direction with its rotational center fixed by a cage ( 140 ), and by configuring the transmission member ( 161 ) such that the transmission member ( 161 ) is able to tilt the first cam ( 131 a ) when rotated and is able to tilt the second cam ( 131 b ) when moved in the axial direction.

Inventors

  • Shotaro Yagi

Assignees

  • TSUBAKIMOTO CHAIN CO.

Dates

Publication Date
20260505
Application Date
20250613
Priority Date
20221219

Claims (6)

  1. 1 . A cam clutch comprising: an outer ring and an inner ring that are provided to be rotatable relative to each other on the same axis; a plurality of cams that are arranged between the outer ring and the inner ring; and a cage that holds the plurality of cams in a circumferential direction, wherein the plurality of cams include a first cam and a second cam that have different engaging directions relative to the outer ring and the inner ring, and are arranged such that the first cam and the second cam form a pair, a transmission member that comes into contact with each of the paired first and second cams and is provided to be rotatable and movable in an axial direction with a rotational center thereof fixed by the cage is provided, and the transmission member is configured to be able to tilt the first cam between an engaging standby state and a state in which the first cam is not in contact with the outer ring or the inner ring when rotated, and is configured to be able to tilt the second cam between an engaging standby state and a state in which the second cam is not in contact with the outer ring or the inner ring when moved in the axial direction.
  2. 2 . The cam clutch according to claim 1 , wherein, when each of the first cam and the second cam is in the engaging standby state, the transmission member is configured to be rotated in response to tilting of the first cam in the engaging direction, thereby tilting the second cam in a disengaging direction.
  3. 3 . The cam clutch according to claim 1 , comprising: a selector that is provided to be movable in the axial direction relative to the cage and is used to move the transmission member, wherein the selector is configured to rotate the transmission member by engaging with the transmission member.
  4. 4 . The cam clutch according to claim 1 , wherein the transmission member has a column-shaped base member part, a load applying part that is provided at one axial end of the base member part, and a cam contacting part that is provided at the other axial end of the base member part, the load applying part has a rotational force acting surface, and the cam contacting part has a cam pressing surface that tilts in a rotational direction relative to the rotational force acting surface and a cam acting surface that tilts the cam, the cam acting surface tilting to separate from the cam pressing surface toward the one axial end and being formed such that one end edge extends along a tilting direction of the rotational force acting surface relative to the cam pressing surface.
  5. 5 . The cam clutch according to claim 1 , wherein the cage is provided to be rotatable independently of the outer ring and the inner ring.
  6. 6 . The cam clutch according to claim 1 , wherein the first cam and the second cam are arranged on the same circumference, and biasing means that biases the first cam and the second cam into an engaging standby state is further provided.

Description

TECHNICAL FIELD The present invention relates to a cam clutch configured to be capable of switching between operation modes, for example, a bidirectional engaging mode in which torque transmission is enabled in both forward and reverse directions between an outer ring and an inner ring, a unidirectional engaging mode in which torque transmission is enabled in one of the forward and reverse directions between the outer ring and the inner ring, and a bidirectional idling mode in which the input-side rotation ring among the outer ring and the inner ring rotates idly in both the forward and reverse directions, thereby cutting off torque transmission between the outer ring and the inner ring. BACKGROUND ART As clutches for controlling torque transmission and cutoff, bidirectional clutches capable of switching between driving and idling in both forward and reverse directions are known. For example, Patent Literature 1 describes a clutch configured to control a retainer that holds both a first sprag and a second sprag, which are biased by biasing means such that their rotation-locking directions are opposed to each other, thereby enabling switching between operation modes, that is, a unidirectional engaging mode in which torque transmission is enabled only in the forward direction between an outer ring and an inner ring, and a unidirectional engaging mode in which torque transmission is enabled only in the reverse direction between the outer ring and the inner ring. CITATION LIST Patent Literature Patent Literature 1: Japanese Patent Application Laid-open No. 2011-231828 SUMMARY OF INVENTION Technical Problem Therefore, generally, in clutches that have sprags arranged symmetrically, which engage only in one rotational direction, and are configured to tilt both one and the other sprags, thereby enabling switching between operation modes, the occurrence of “engagement” in which all cams engage at the same time is likely. In other words, in such clutches, one sprag tilts to immediately start engaging with an outer ring and an inner ring when torque is applied to the outer ring or the inner ring. When the torque is removed, the one sprag tilts in the disengaging direction and transitions into an idling state. However, during this time, the other sprag tilts in the engaging direction and starts engaging with the outer ring and the inner ring before the disengagement of the one sprag. As a result, the occurrence of “engagement” in which all cams engage at the same time is likely. In such a state, all the sprags engage with high surface pressure. Therefore, when switching the operation modes of the clutches, a large force is required to change the posture of the sprags, damaging the engaging surfaces of the sprags against the outer ring and the inner ring, or the raceway surfaces of the outer ring and the inner ring. Consequently, the service life of the clutches may be shortened. In order to solve this problem, the bidirectional clutch described above has the first and second sprags arranged side by side in the common retainer such that their locking directions are opposite to each other, and is configured to hold the first and second sprags in a biased state, with the first sprags biased in the anti-locking direction and the second sprags biased in the locking direction, thereby preventing the occurrence of engagement. However, the bidirectional clutch described above is configured to control the retainer during switching between the operation modes, thereby forcibly tilting all the first and second sprags at once. Therefore, the bidirectional clutch described above cannot realize a bidirectional engaging mode in which torque transmission is enabled in both the forward and reverse directions between the outer ring and the inner ring, and a bidirectional idling mode in which the input-side rotation ring among the outer ring and the inner ring is rotated idly in both the forward and reverse directions, thereby cutting off torque transmission between the outer ring and the inner ring. Furthermore, since slip torque occurs when any one of the first and second sprags comes into contact with the inner ring and the outer ring during idling, torque during the idling increases. Moreover, due to a configuration in which the retainer is controlled by applying a load from a load applying unit to the retainer via a gear mechanism, the torque during idling also increases since the gears linked to the retainer act as rotational resistance. The present invention has been made in view of the above circumstances and aims to provide a cam clutch that enables smooth switching between operation modes while preventing the occurrence of cam engagement, and achieves noise reduction and long service life with a simple structure, without upsizing and increasing the number of components. Solution to Problem In order to solve the above problem, the present invention provides a cam clutch including: an outer ring and an inner ring that are provide