Patent Description:
As one type of clutch that controls transmission and interruption of a rotary force, switchable two-way clutches that can drive and freewheel in both forward and reverse directions are known.

Some types of two-way clutches are configured to switch between a locked state that prohibits relative rotation between the inner race and the outer race (transmits the rotary force) and a free state that allows relative rotation between the inner race and the outer race (interrupts the rotary force) by tilting cams or sprags (see, for example, Patent Literature <NUM> and Patent Literature <NUM>).

Patent Literature <NUM> describes a clutch configured to be switchable among three operating modes, i.e., two-way free mode allowing rotation in both forward and reverse directions, one-way lock mode allowing rotation only in the forward direction, and one-way lock mode allowing rotation only in the reverse direction, by controlling a retainer that retains both first sprags and second sprags, which are biased by biasing means toward opposite directions in which they lock rotation.

A cam clutch comprising the features defined within the preamble of claim <NUM> is described in patent literature <NUM>.

The two-way clutch described in Patent Literature <NUM> switches the states of engagement and separation between an input-side rotary member and an output-side rotary member by means of sprags that are tilted in the same direction as the rotation direction of the input-side rotary member when the input-side rotary member is rotated relative to the output-side rotary member. This poses the problem of poor responsiveness due to the time lost when the rotation direction is switched. The two-way clutch described in Patent Literature <NUM> entails the same problem.

Another problem was that, while the plurality of cams are circumferentially equally spaced by the retainer, the cams are, in actuality, disposed movably within a certain range of angles in respective pockets of the retainer, so that there are variations in the position (attitude) of adjacent cams, and the operation timing of the cams varied easily.

The present invention solves these problems, with an aim to provide a cam clutch capable of switching from one operating mode to another and offering improved stability of clutch operations and high responsiveness.

The present invention solves the above problems by providing a cam clutch having the features as defined within claim <NUM>.

According to the invention set forth in claim <NUM>, the circumferential position of each of the plurality of cams is restricted and the positional relationship between adjacent cams and the attitude of the cams are kept consistent, and therefore behavioral variations of cams when the cam attitude change part is driven to tilt the cams can be avoided. Since the distance between the load application point and the load support point can be set sufficiently large, a larger moment acts on the cams when the cam attitude change part moves, meaning that the attitude of the cams can be changed with a smaller force and with less influence of production variations of components. The stability of clutch operations can thus be improved and high responsiveness can be achieved.

According to the invention set forth in claim <NUM>, the circumferential position of the cams and the attitude of the cams can be restricted more reliably, so that the stability of clutch operations can be improved and high responsiveness can be achieved reliably.

According to the invention set forth in claim <NUM>, the desired effects can be reliably achieved without an increase in the number of components and with a simple structure.

According to the invention set forth in claim <NUM>, the first cam and the second cam rotate in different directions for making engagement, meaning that the attitudes of one or both of the first cam and second cam can be selectively changed, which makes possible the switching among four operating modes, i.e., the two-way free mode allowing rotation in both forward and reverse directions, one-way lock mode allowing rotation in either one of the forward and reverse directions, and the two-way lock mode prohibiting rotation in both forward and reverse directions.

The invention according to claim <NUM> allows for easy switching among the four operating modes described above.

Embodiments of the present invention are described with reference to <FIG>. Note, however, the present invention is not limited to these embodiments.

The cam clutch <NUM> according to a first embodiment of the present invention includes an inner race <NUM> and an outer race <NUM> that are rotatable relative to each other on the same X axis, and a cam mechanism <NUM> that transmits and interrupts power between the inner race <NUM> and the outer race <NUM>, as shown in <FIG>.

The cam mechanism <NUM> is made up of a plurality of cams <NUM> arranged between the inner race <NUM> and the outer race <NUM>, a cam cage <NUM> holding each of the plurality of cams <NUM> on the same circumference at predetermined circumferential intervals, and an annular garter spring <NUM> that is a biasing means that biases each of the plurality of cams <NUM> to make contact with the inner race <NUM> and the outer race <NUM>.

The cam <NUM> includes, as shown in <FIG>, a head part <NUM> having a circumferential surface formed in an arcuate curved shape protruding radially outward and constituting a radially outer engagement surface <NUM> making contact with the outer race <NUM>, a leg part <NUM> having a circumferential surface formed in an arcuate curved shape protruding radially inward and constituting a radially inner engagement surface <NUM> making contact with the inner race <NUM>, and a strut part <NUM> connecting the head part <NUM> and the leg part <NUM>. The head part <NUM> extends out from the strut part <NUM> in the circumferential direction.

The radially outer engagement surface <NUM> of the cam <NUM> is formed with a garter spring mount groove <NUM> for receiving the garter spring <NUM> fitted therein, in a central part in a direction perpendicular to the end face of the cam <NUM> (X-axis direction). The garter spring mount groove <NUM> is designed to impart a clockwise (in <FIG>) rotational moment to the cam <NUM> when it is biased by the garter spring <NUM> radially inward.

The cam cage <NUM> has circumferentially equally spaced pockets <NUM> as shown in <FIG>.

This cam cage <NUM> includes a pair of annular plates <NUM> and <NUM> axially opposite each other, and a plurality of columnar parts <NUM> axially extending at circumferentially equally spaced positions and connecting the annular plates <NUM> and <NUM>, the spaces between adjacent columnar parts <NUM> forming the pockets <NUM>. One annular plate <NUM> is designed to have larger outer dimensions than the other annular plate <NUM> so that it is placed in contact with the bottom surface of a recess formed in one end face of the outer race <NUM>.

Each of the columnar parts <NUM> protrudes radially outward more than the outer peripheral edge of the other annular plate <NUM>, and is formed with a circumferentially extending garter spring mount groove <NUM> in an outer circumferential surface thereof.

The cams <NUM> are inserted into the pockets <NUM> from the leg part <NUM> side such that the strut parts <NUM> are positioned inside the pockets <NUM>, and with the garter spring <NUM> mounted, the cams are held on the cam cage <NUM>. With the cams <NUM> held on the cam cage <NUM>, a corner part on one side of the head part <NUM> of the cam <NUM> abuts on a side face on the other side of the columnar part <NUM>. This restricts the circumferential position of the cam <NUM>, as well as the attitude of the cam <NUM>, so that all the cams <NUM> are brought in contact with the inner race <NUM> and outer race <NUM> without variations in their attitude (inclination).

This cam clutch <NUM> is provided with a cage rotation stopper <NUM> that is fixed to the outer race <NUM> and prohibits relative rotation of the cam cage <NUM> relative to the inner race <NUM> and outer race <NUM>.

The cage rotation stopper <NUM> includes an annular plate part <NUM> that makes surface contact with one annular plate <NUM> of the cam cage <NUM> and restricts axial movements of the cam mechanism <NUM>, a circumferential wall part <NUM> fitted over the outer race <NUM> and axially extending from an outer peripheral edge on one side of the annular plate part <NUM>, and a plurality of stopper parts <NUM> axially extending at an inner peripheral edge of the annular plate part <NUM> to be inserted into grooves <NUM> formed in the corresponding columnar parts <NUM> of the cam cage <NUM>. An engaging pawl <NUM> is formed on the circumferential wall part <NUM>, to make sliding engagement with an axially extending recessed groove <NUM> formed on the outer circumferential surface of the outer race <NUM>.

The cam clutch <NUM> according to this embodiment is provided with an operating mode switch means <NUM> for switching between a free state that allows relative rotation between the inner race <NUM> and outer race <NUM> and a locked state that prohibits relative rotation between the inner race <NUM> and outer race <NUM>.

The operating mode switch means <NUM> of this embodiment includes an annular plate-like end wall part <NUM>, a plurality of tab members <NUM> axially extending from an inner peripheral edge on one side of the end wall part <NUM> and functioning as a cam attitude change part, and a circumferential wall part <NUM> axially extending from an outer peripheral edge on one side of the end wall part <NUM>. The operating mode switch means <NUM> is provided such that its circumferential wall part <NUM> is fitted over the circumferential wall part <NUM> of the cage rotation stopper <NUM> via a cylindrical bearing member <NUM>, and the plurality of tab members <NUM> are located close to the outer circumferential surface of the inner race <NUM> between the leg parts <NUM> of adjacent cams <NUM>.

Hereinafter, the operation of the cam clutch <NUM> according to the above first embodiment will be described.

The cam clutch <NUM> is in the one-way lock mode in which rotation of the outer race <NUM> relative to the inner race <NUM> in the forward direction (clockwise in <FIG>) is prohibited when the tab members <NUM> constituting the cam attitude change part of this cam clutch <NUM> are at the neutral position, and can be switched from the one-way lock mode to the two-way free mode in which the outer race <NUM> is allowed to rotate relative to the inner race <NUM> in forward and reverse directions by operation of the operating mode switch means <NUM>.

Namely, when the operating mode switch means <NUM> is rotated in the forward direction, each of the plurality of tab members <NUM> moves circumferentially in the forward direction relative to the cams <NUM>, which causes the cams <NUM> to tilt around a load support point as the center of rotation in a direction in which they are disengaged from the inner race <NUM> and outer race <NUM>. In this cam clutch <NUM>, the head parts <NUM> of the cams <NUM> abut on the columnar parts <NUM> of the cam cage <NUM> such that, as shown in <FIG>, the load support point Sp is located radially between a load application point Ap of the tab member <NUM> on the cam <NUM> and a distal contact point Ep between the cam and the outer race <NUM>, or a contact point between the cam and a raceway positioned on the radially distal side relative to the load application point Ap on the cam <NUM>. The radial distance d1 between the load application point Ap and the load support point Sp is larger than the radial distance d2 between the load support point Sp and the distal contact point Ep. Such a configuration allows the distance between the load application point Ap and the load support point Sp to be sufficiently large, and increases the moment that acts on the cams <NUM> when the tab members <NUM> move, meaning that the attitude of the cams <NUM> can be changed with a smaller force and with less influence of production variations of components. Since all the cams <NUM> are in contact with the inner race <NUM> and outer race <NUM> without variations in their attitude (inclination), behavioral variations of the cams <NUM> can be avoided. The stability of clutch operations can thus be improved and high responsiveness can be achieved.

<FIG> is a lateral cross-sectional view perpendicular to the X axis illustrating part of the configuration of one example of the cam clutch according to a second embodiment of the present invention.

This cam clutch has a configuration similar to the cam clutch <NUM> according to the first embodiment except that the operating mode switch means <NUM> is designed to have the tab members <NUM> as the cam attitude change part positioned between the head parts <NUM> of adjacent cams <NUM>, while the cam cage <NUM> abuts on the leg parts <NUM> of the cams <NUM> to form the load support points Sp.

The cam cage <NUM> includes, as shown in <FIG>, a pair of annular plates <NUM> and <NUM> axially opposite each other, a plurality of columnar parts <NUM> axially extending at circumferentially equally spaced positions and connecting the annular plates <NUM> and <NUM>, and a plurality of connecting plates <NUM> provided at the outer peripheral edge in the circumferential middle position between adjacent columnar parts <NUM> and connecting the annular plates <NUM> and <NUM>. Each of the columnar parts <NUM> is provided, at one radially inner end thereof, with a protruded portion <NUM> protruding in one circumferential direction. The spaces between the columnar parts <NUM> and the connecting plates <NUM> positioned on the side where the columnar parts <NUM> have their protruded portions <NUM> form the pockets <NUM>.

One annular plate <NUM> is formed with notches <NUM> that are in communication with the spaces formed between the pockets <NUM>, for receiving the stopper parts <NUM> of the cage rotation stopper <NUM> inserted thereto.

In the cam clutch according to the above second embodiment, when the operating mode switch means <NUM> is rotated in the reverse direction (e.g., counterclockwise in <FIG>), for example, each of the plurality of tab members <NUM> moves circumferentially in the reverse direction relative to the cams <NUM>, which causes the cams <NUM> to tilt around the load support points Sp as the center of rotation in a direction in which they are disengaged from the inner race <NUM> and outer race <NUM>. Since the distance between the load application point Ap and the load support point Sp is sufficiently large, the moment that acts on the cams <NUM> when the tab members <NUM> move is larger, meaning that the attitude of the cams <NUM> can be changed with a smaller force and with less influence of production variations of components. Since all the cams <NUM> are in contact with the inner race <NUM> and outer race <NUM> without variations in their attitude (inclination), behavioral variations of the cams <NUM> can be avoided. The stability of clutch operations can thus be improved and high responsiveness can be achieved.

In the cam clutch <NUM> according to the first embodiment, the cams are biased by the garter spring <NUM> and the corner part on one side of the head part <NUM> of the cam <NUM> abuts on the other side face of the columnar part <NUM>, which restricts the circumferential position of the cam <NUM>, as well as the attitude of the cam <NUM>. In the cam clutch according to the second embodiment, the cams are biased by the garter spring <NUM> such that the leg parts <NUM> of the cams <NUM> on the other side abut on the protruded portions <NUM> of the columnar parts <NUM>, to restrict the circumferential positions of the cams <NUM>, as well as the attitude of the cams <NUM>. Alternatively, a position restricting part that restricts the circumferential positions of the cams <NUM> and the attitude of the cams <NUM> may be separately provided.

<FIG> is a lateral cross-sectional view perpendicular to the X axis illustrating part of the configuration of one example of the cam clutch according to a third embodiment of the present invention.

This cam clutch has a configuration similar to the cam clutch <NUM> according to the first embodiment except that position restricting parts <NUM> are provided on the inner circumferential surface of the outer race <NUM>, which is the raceway positioned on the radially distal side relative to the tab members <NUM> that form the cam attitude change part.

The position restricting parts <NUM> are provided on the inner circumferential surface of the outer race <NUM> at circumferentially equally spaced positions such as to protrude radially inward. The position restricting parts need not be formed integrally with the outer race <NUM> and may be separately formed parts that are fixed to the outer race <NUM>.

The cam cage <NUM> includes, as shown in <FIG>, a pair of annular plates <NUM> and <NUM> axially opposite each other, and a plurality of columnar parts <NUM> axially extending at circumferentially equally spaced positions and connecting the annular plates <NUM> and <NUM>. One annular plate <NUM> is designed to have larger outer dimensions than the other annular plate <NUM> so that it is placed in contact with the bottom surface of a recess formed in one end face of the outer race <NUM>. The columnar parts <NUM> are continuous with the inner edge of one annular plate <NUM> at one end, and continuous with the outer edge of the other annular plate <NUM> at the other end.

In this cam cage <NUM>, the spaces between adjacent columnar parts <NUM> form, circumferentially alternately, pockets <NUM> in which the cams <NUM> are disposed and stopper accommodating parts <NUM> in which the stopper parts <NUM> of the cage rotation stopper <NUM> are positioned.

In this cam clutch, the cams <NUM> are biased by the garter spring <NUM> and one side face of the head parts <NUM> of the cams <NUM> abuts on the position restricting parts <NUM> such that the load support point Sp is located radially between a load application point Ap of the tab member <NUM> on the cam <NUM> and a distal contact point Ep between the cam and the outer race <NUM>, or a contact point between the cam and a raceway positioned on the radially distal side relative to the load application point Ap on the cam <NUM>. The load support point Sp is located at such a radial position that the radial distance between the load application point Ap and the load support point Sp is larger than the radial distance between the load support point Sp and the distal contact point Ep.

In this cam clutch, when the operating mode switch means <NUM> is rotated in the forward direction (e.g., clockwise in <FIG>), each of the plurality of tab members <NUM> moves circumferentially in the forward direction relative to the cams <NUM>, which causes the cams <NUM> to tilt around the load support points Sp as the center of rotation in a direction in which they are disengaged from the inner race <NUM> and outer race <NUM>. Since the distance between the load application point Ap and the load support point Sp is sufficiently large, the moment that acts on the cams <NUM> when the tab members <NUM> move is larger, meaning that the attitude of the cams <NUM> can be changed with a smaller force and with less influence of production variations of components. Since the position restricting parts <NUM> keep all the cams <NUM> in contact with the inner race <NUM> and outer race <NUM> without variations in their attitude (inclination), behavioral variations of the cams <NUM> can be avoided. The stability of clutch operations can thus be improved and high responsiveness can be achieved.

In the case where the operating mode switch means <NUM> is designed to have the tab members <NUM> as the cam attitude change part positioned between the head parts <NUM> of adjacent cams <NUM>, the position restricting parts may be formed on the outer circumferential surface of the inner race.

<FIG> is a lateral cross-sectional view perpendicular to the X axis illustrating part of the configuration of one example of the cam clutch according to a fourth embodiment of the present invention.

This cam clutch has a basic configuration similar to the cam clutch according to the second embodiment except that position restricting parts <NUM> are provided on the outer circumferential surface of the inner race <NUM>, which is the raceway positioned on the radially distal side relative to the tab members <NUM> that form the cam attitude change part.

The position restricting parts <NUM> are provided on the outer circumferential surface of the inner race <NUM> at circumferentially equally spaced positions such as to protrude radially outward. The position restricting parts need not be formed integrally with the inner race <NUM> and may be separately formed parts that are fixed to the inner race <NUM>.

The cam cage <NUM> includes, as shown in <FIG>, a pair of annular plates <NUM> and <NUM> axially opposite each other, and a plurality of columnar parts <NUM> axially extending at circumferentially equally spaced positions and connecting the annular plates <NUM> and <NUM>.

In this cam clutch, the cams <NUM> are biased by the garter spring <NUM> and the other side face of the leg parts <NUM> of the cams <NUM> abuts on the position restricting parts <NUM> such that the load support point Sp is located radially between a load application point Ap of the tab member <NUM> on the cam <NUM> and a distal contact point Ep between the cam and the inner race <NUM>, or a contact point between the cam and a raceway positioned on the radially distal side relative to the load application point Ap on the cam <NUM>. The load support point Sp is located at such a radial position that the radial distance between the load application point Ap and the load support point Sp is larger than the radial distance between the load support point Sp and the distal contact point Ep.

In this cam clutch, when the operating mode switch means <NUM> is rotated in the reverse direction (e.g., counterclockwise in <FIG>), each of the plurality of tab members <NUM> moves circumferentially in the reverse direction relative to the cams <NUM>, which causes the cams <NUM> to tilt around the load support points Sp as the center of rotation in a direction in which they are disengaged from the inner race <NUM> and outer race <NUM>. Since the distance between the load application point Ap and the load support point Sp is sufficiently large, the moment that acts on the cams <NUM> when the tab members <NUM> move is larger, meaning that the attitude of the cams <NUM> can be changed with a smaller force and with less influence of production variations of components. Since the plate springs as the position restricting means act to keep all the cams <NUM> in contact with the inner race <NUM> and outer race <NUM> without variations in their attitude (inclination), behavioral variations of the cams <NUM> can be avoided. The stability of clutch operations can thus be improved and high responsiveness can be achieved.

While a garter spring is used as the biasing means to bias the cams radially inward in the configurations described above, the cam clutch of the present invention may be configured such that the cams are biased radially outward by a biasing means, or such that the cams are biased in a circumferential direction.

<FIG> is a lateral cross-sectional view perpendicular to the X axis illustrating part of the configuration of one example of the cam clutch according to a fifth embodiment of the present invention.

This cam clutch has a basic configuration similar to the cam clutch <NUM> according to the first embodiment except that plate springs <NUM> are used instead of the garter spring as the biasing means for biasing the cams <NUM> in a circumferential direction.

The plate springs <NUM> are each provided between one side face of the columnar parts <NUM> of the cam cage <NUM> and the other side face of the head parts <NUM> of the cams <NUM> so as to impart a clockwise (in <FIG>) rotational moment to the cams <NUM> and also to function as position restricting means that restrict the circumferential positions of the cams <NUM> and the attitude of the cams <NUM>.

In this cam clutch, the cams <NUM> are circumferentially biased by the plate springs <NUM> and a corner part of the head part <NUM> of the cam <NUM> on one side abuts on the other side face of the columnar part <NUM> such that the load support point Sp is located radially between a load application point Ap of the tab member <NUM> on the cam <NUM> and a distal contact point Ep between the cam and the outer race <NUM>, or a contact point between the cam and a raceway positioned on the radially distal side relative to the load application point Ap on the cam <NUM>. The load support point Sp is located at such a radial position that the radial distance between the load application point Ap and the load support point Sp is larger than the radial distance between the load support point Sp and the distal contact point Ep.

In this cam clutch, when the operating mode switch means <NUM> is rotated in the forward direction (clockwise in <FIG>), each of the plurality of tab members <NUM> moves circumferentially in the forward direction relative to the cams <NUM>, which causes the cams <NUM> to tilt around the load support points Sp as the center of rotation in a direction in which they are disengaged from the inner race <NUM> and outer race <NUM>. Since the distance between the load application point Ap and the load support point Sp is sufficiently large, the moment that acts on the cams <NUM> when the tab members <NUM> move is larger, meaning that the attitude of the cams <NUM> can be changed with a smaller force and with less influence of production variations of components. Since the plate springs <NUM> as the position restricting means act to keep all the cams <NUM> in contact with the inner race <NUM> and outer race <NUM> without variations in their attitude (inclination), behavioral variations of the cams <NUM> can be avoided. The stability of clutch operations can thus be improved and high responsiveness can be achieved.

The cam clutch according to the above second embodiment, the cam clutch according to the above third embodiment, and the cam clutch according to the above fourth embodiment may also be configured to use plate springs as biasing means for biasing the cams <NUM> circumferentially instead of the garter spring.

<FIG> is a lateral cross-sectional view perpendicular to the X axis illustrating part of the configuration of one example of the cam clutch according to a sixth embodiment of the present invention.

This cam clutch has a basic configuration similar to the cam clutch according to the above second embodiment except that plate springs are used instead of the garter spring as the biasing means for biasing the cams <NUM> in a circumferential direction.

The plate springs <NUM> are each provided inside the pockets of the cam cage <NUM> between one side face of the strut parts <NUM> of the cams <NUM> and the other side face of the connecting plates <NUM> so as to impart a clockwise (in <FIG>) rotational moment to the cams <NUM> and also to function as position restricting means that cause the other side face of the leg parts <NUM> of the cams <NUM> to abut on the protruded portions <NUM> of the columnar parts <NUM> of the cam cage <NUM> for restricting the circumferential positions of the cams <NUM> and the attitude of the cams <NUM>.

<FIG> is a lateral cross-sectional view perpendicular to the X axis illustrating part of the configuration of one example of the cam clutch according to a seventh embodiment of the present invention.

This cam clutch has a basic configuration similar to the cam clutch according to the above third embodiment except that plate springs are used instead of the garter spring as the biasing means for biasing the cams <NUM> in a circumferential direction, and that the cam cage has a different configuration.

The cam cage <NUM> has a configuration similar to the cam cage <NUM> of the cam clutch according to the third embodiment except that the columnar parts <NUM> positioned circumferentially on the other side of the pockets have a protruded portion <NUM> that is formed such as to protrude radially outward from an outer peripheral edge of the other annular plate.

The plate springs <NUM> are each provided between one side face of the protruded portions <NUM> of the columnar parts <NUM> of the cam cage <NUM> and the other side face of the head parts <NUM> of the cams <NUM> so as to impart a clockwise (in <FIG>) rotational moment to the cams <NUM> and also to function as position restricting means that cause one side face of the head parts <NUM> of the cams <NUM> to abut on the position restricting parts <NUM> formed on the outer race <NUM> for restricting the circumferential positions of the cams <NUM> and the attitude of the cams <NUM>.

<FIG> is a lateral cross-sectional view perpendicular to the X axis illustrating part of the configuration of one example of the cam clutch according to an eighth embodiment of the present invention.

This cam clutch has a basic configuration similar to the cam clutch according to the above fourth embodiment except that plate springs are used instead of the garter spring as the biasing means for biasing the cams <NUM> in a circumferential direction.

The plate springs <NUM> are each provided inside the pockets of the cam cage <NUM> between one side face of the strut parts <NUM> of the cams <NUM> and the other side face of the connecting plates <NUM> so as to impart a clockwise (in <FIG>) rotational moment to the cams <NUM> and also to function as position restricting means that cause one side face of the leg parts <NUM> of the cams <NUM> to abut on the position restricting parts <NUM> formed on the inner race <NUM> for restricting the circumferential positions of the cams <NUM> and the attitude of the cams <NUM>.

In the cam clutch according to the sixth embodiment and in the cam clutch according to the eighth embodiment, when the operating mode switch means <NUM> is rotated in the reverse direction, each of the plurality of tab members <NUM> moves circumferentially in the reverse direction relative to the cams <NUM>, which causes the cams <NUM> to tilt around the load support points Sp as the center of rotation in a direction in which they are disengaged from the inner race <NUM> and outer race <NUM>. In the cam clutch according to the seventh embodiment, when the operating mode switch means <NUM> is rotated in the forward direction, each of the plurality of tab members <NUM> moves circumferentially in the forward direction relative to the cams <NUM>, which causes the cams <NUM> to tilt around the load support points Sp as the center of rotation in a direction in which they are disengaged from the inner race <NUM> and outer race <NUM>.

Since the distance between the load application point Ap and the load support point Sp is sufficiently large, the moment that acts on the cams <NUM> when the tab members <NUM> move is larger, meaning that the attitude of the cams <NUM> can be changed with a smaller force and with less influence of production variations of components. Since the plate springs <NUM> as the position restricting means act to keep all the cams <NUM> in contact with the inner race <NUM> and outer race <NUM> without variations in their attitude (inclination), behavioral variations of the cams <NUM> can be avoided. The stability of clutch operations can thus be improved and high responsiveness can be achieved.

While embodiments of the present invention have been described above in detail, the present invention is not limited to the embodiments described above. Various design changes may be made without departing from the scope of the present invention set forth in the claims.

The above embodiments featured configurations in which the cams are biased by the biasing means to make contact with the inner race and outer race and tilted by the operating mode switch means to disengage from the inner race and outer race. Alternatively, the cams may be biased by the biasing means to separate from the inner race or outer race and tilted by the operating mode switch means to engage with the inner race and outer race.

The cams forming the cam mechanism may be designed to make frictional engagement with the inner race and outer race when rotated to either of the forward direction and reverse direction.

Moreover, while the operating mode switch means described in the above embodiments is configured to move the cam attitude change part circumferentially independently of rotation of the inner race and outer race, the operating mode switch means may be configured to move the cam attitude change part radially or axially independently of rotation of the inner race and outer race.

The cam cage and the cage rotation stopper may be integrally formed.

The above embodiments featured configurations provided with a cam mechanism with a plurality of identical cams circumferentially arranged on the same circumference and imparted with a rotational moment in the same direction by the biasing means. Alternatively, the cam mechanism may be designed to include a first cam and a second cam imparted with a rotational moment in different directions by the biasing means. In such a design, the first cam would be configured to make frictional engagement with the inner race and outer race when the outer race rotates in one direction, for example, and be tilted in a direction in which it cancels the frictional engagement with the inner race and outer race when the outer race rotates in the other direction. The second cam would be configured to make frictional engagement with the inner race and outer race when the outer race rotates in the other direction, for example, and be tilted in a direction in which it cancels the frictional engagement with the inner race and outer race when the outer race rotates in one direction.

The arrangement of the first cams and second cams is not limited to a particular layout. The first cams and second cams may be aligned on the same circumference, or a plurality of rows of a plurality of cams circumferentially aligned on the same circumference may be arranged side by side in the axial direction. In a configuration provided with a plurality of rows of cams, each row of cams may include only one of the first cam and second cam, or may include both of the first cam and second cam. The numbers of the first cams and second cams may be the same, or different.

In a case where the first cams and second cams are aligned on the same circumference, the first cams and second cams may be circumferentially alternately arranged, or the first and second cams may not be alternately arranged.

The operating mode switch means may be configured to be able to change the attitude of the first cam and the attitude of the second cam simultaneously, or to change the attitude of the first cam and the attitude of the second cam independently.

Alternatively, the attitudes of the first cam and the second cam may be changed by different operating mode switch means. In this case, for example, the operating mode switch means is provided on both sides in the axial direction of the cam mechanism, one operating mode switch means being configured to change the attitude of the first cams, and another operating mode switch means being configured to change the attitude of the second cams. The cam clutch with such a configuration can switch among four operating modes, two-way lock mode, forward direction lock mode, reverse direction lock mode, and two-way free mode.

Claim 1:
A cam clutch comprising: an inner race (<NUM>) and an outer race (<NUM>) that are coaxial and rotatable relative to each other; a plurality of cams (<NUM>) circumferentially arranged at intervals between the inner race (<NUM>) and the outer race (<NUM>); a biasing means (<NUM>) biasing each of the plurality of cams (<NUM>) so that each of the plurality of cams (<NUM>) makes contact with the inner race (<NUM>) and the outer race (<NUM>); and
an operating mode switch means (<NUM>) including a cam attitude change part (<NUM>) that is drivable independently of rotation of the inner race (<NUM>) and the outer race (<NUM>) to forcibly tilt the cams (<NUM>),
characterized in that
a load support point (Sp) is located radially between a load application point (Ap) of the cam attitude change part (<NUM>) on the cam (<NUM>) and a distal contact point (Ep) of the cam (<NUM>) on a raceway that is one of the inner race (<NUM>) and the outer race (<NUM>) positioned on a radially distal side relative to the load application point (Ap), a radial distance (d1) between the load application point (Ap) and the load support point (Sp) being larger than a radial distance (d2) between the load support point (Sp) and the distal contact point (Ep), and
the cams (<NUM>) are tilted around the load support point (Sp) as the center of rotation when the cam attitude change part (<NUM>) moves.