Rotation transmission device

Abstract

A rolling bearing (3) is disposed between an inner ring (1) and an outer ring (2) of this rotation transmission device. A retainer (6) has a flange part (6a) extending in the radial direction from between a cam ring part (1b) and an inner raceway ring (3a). The cam ring part (1b) has a restriction surface (1e) that receives the flange part (6a) in the axial direction, and a retainer seat surface (1f) that receives the flange part (6a) in the radial direction. A ring-shaped spacer (18) is provided on a non-restriction surface (1e) side of the flange part (6a). The inner ring (1) has a spacer seat surface (1g) that receives the spacer (18) in the radial direction, and the cam ring part (1b) has a step surface (1h) that receives the spacer (18) in the axial direction. The spacer (18) is axially sandwiched between the step surface (1h) and the inner raceway ring (3a). Thus, the axial length of the inner ring (1) is shortened while avoiding interference from the retainer (6) and the outer ring (2).

Description

Rotation Transmission Device

[0001] The present invention relates to a rotation transmission device that transmits and cuts off rotational torque.

[0002] Conventionally, there has been a rotation transmission device in which a rolling bearing and multiple engaging elements are arranged between an inner ring and an outer ring, and these engaging elements are held at multiple locations circumferentially by an annular cage, and when an electromagnet is excited or de-excited, the cage is moved to an engaged position, thereby transmitting rotational torque between the inner ring and the outer ring via the engaging elements, and when the electromagnet is excited or de-excited, the cage is moved to a released position, thereby interrupting the transmission of rotational torque.

[0003] In the rotation transmission devices disclosed in Patent Documents 1 and 2, the inner ring has a bearing seat that fits into the inner raceway of the rolling bearing, and a cam ring portion that is larger in diameter than the bearing seat. Multiple engaging elements are disposed between the cam ring portion and the inner periphery of the outer ring. The inner ring is made of metal. The cam ring portion has a cam surface that contacts the engaging elements. To improve the surface hardness of this cam surface, the cam surface of the cam ring portion is subjected to heat treatment such as carburizing. Because forming pockets for accommodating the engaging elements at multiple locations around the circumference by machining is costly, the cage is generally made of a single part formed by press working such as punching or drawing. The cage is positioned axially and radially relative to the inner ring.

[0004] In the rotation transmission device of Patent Document 1, the cage has a flange with an L-shaped cross section between the cam ring portion and the inner raceway. The cam ring portion has a restriction surface that axially receives the cage flange, a cage seating surface that radially receives the flange, and a shoulder end surface that axially receives the inner raceway. The cage flange axially abuts against the inner raceway at a plate thickness surface located at the tip of the axial side of the L-shaped cross section. The cage is positioned radially by the cage seating surface and is sandwiched axially between the restriction surface of the cam ring portion and the inner raceway.

[0005] In the rotation transmission device of Patent Document 2, the cage has a flange extending radially between the cam ring portion and the inner raceway ring. The cam ring portion has a restriction surface that axially receives the cage flange, a cage seating surface that radially receives the flange, and a shoulder end surface that axially receives the inner raceway ring. The inner ring has a retaining ring groove in an intermediate portion between the retainer seating surface and the shoulder end surface. The cage is positioned radially by the cage seating surface, and axially by a retaining ring attached to the retaining ring groove.

[0006] JP 2006-275247 A JP 2009-216213 A

[0007] When the flange of the cage is press-formed into an L-shaped cross section, as in the rotation transmission device of Patent Document 1, it is difficult to reduce the radius of curvature of the bent portion to prevent cracks at the bent portion extending from the radial side to the axial side, and further, the inner diameter surface of the axial side needs to have a sufficient axial length for guiding the cage, which results in a large axial length of the flange.As a result, the axial length between the restricting surface of the cam ring portion and the inner raceway ring (bearing seat surface) becomes large.

[0008] If a flange portion extending in the radial direction is employed, as in the cage of the rotation transmission device of Patent Document 2, it is possible to reduce the axial length of the flange portion.

[0009] However, when a retaining ring is disposed on the opposite side of the flange of the retainer to the restriction surface, as in the rotation transmission device of Patent Document 2, if the inner ring has an excessively thin portion, deformation and cracks will occur in the thin portion due to the heat treatment described above, so it is necessary to ensure sufficient thickness in the axial and radial directions around the retainer seating surface and the retaining ring groove. Therefore, the axial length between the retaining ring groove and the shoulder end face cannot be reduced, and the axial length between the restriction surface of the cam ring portion and the inner raceway ring (bearing seating surface) will still be large.

[0010] On the other hand, if the axial length between the restricting surface of the cam ring portion and the bearing seat surface is made too short, it will be impossible to ensure an axial gap between the retainer and the retaining ring that restricts the outer raceway of the rolling bearing, resulting in the problem of interference between the retainer on the inner ring side and the outer ring side.

[0011] In view of the above background, the problem that this invention aims to solve is to shorten the axial length of the inner ring while avoiding interference between the outer ring and a retainer that holds multiple engaging elements between the cam ring portion of the inner ring and the outer ring.

[0012] In order to achieve the above object, the present invention provides a bearing assembly comprising an inner ring, an outer ring surrounding the inner ring, a rolling bearing arranged between the inner ring and the outer ring, and a clutch mechanism for transmitting and blocking rotational torque, wherein the rolling bearing has an inner raceway, an outer raceway, and a plurality of rolling elements arranged between the inner and outer raceways, the inner ring has a bearing seat that fits into the inner raceway and a cam ring portion that is provided with a larger diameter than the bearing seat, and the clutch mechanism has a plurality of engaging elements that are arranged at predetermined intervals in the circumferential direction between the cam ring portion and the outer ring, and a retainer that retains these engaging elements, the cam ring portion has a flange portion extending radially between the cam ring portion and the inner raceway ring, the cam ring portion having a cam surface that contacts the engaging element, a restriction surface that receives the flange portion in the axial direction, and a retainer seat surface that receives the flange portion in the radial direction, the rotation transmission device further comprising a spacer on the anti-restriction surface side of the flange portion, the spacer being ring-shaped, the inner ring having a spacer seat surface that receives the spacer in the radial direction, the cam ring portion having a stepped surface that receives the spacer in the axial direction, and the spacer being sandwiched in the axial direction between the stepped surface and the inner raceway ring.

[0013] According to the above-described configuration 1, the ring-shaped spacer is positioned radially by the spacer seat surface of the inner ring and axially by the stepped surface of the cam ring portion and the inner raceway ring of the rolling bearing. Therefore, the cage is positioned axially by the restricting surface of the cam ring portion that axially receives the collar portion of the cage and the spacer that is restricted by the inner raceway ring at a position adjacent to the opposite side of the restricting surface of the collar portion. Because no groove such as a retaining ring groove is used to position the spacer, there is no groove shoulder sandwiched between the spacer and the inner raceway ring, thereby reducing the axial length of the inner ring. Furthermore, because the spacer adjacent to the collar portion of the cage is sandwiched between the stepped surface of the cam ring portion and the inner raceway ring, it is possible to appropriately secure the axial distance between the outer raceway ring and the cage, and interference between the cage and the outer ring side is avoided.

[0014] In the above configuration 1, a configuration 2 can be adopted in which the spacer seating surface and the bearing seating surface are formed in the same plane that is continuous in the axial direction.

[0015] According to the above configuration 2, there is no step between the spacer seating surface and the bearing seating surface, and the inner ring shape can be prevented from becoming complicated.

[0016] In the above configuration 1 or 2, a configuration 3 can be adopted in which a snap ring is attached to the outer ring between the cage and the outer raceway ring, and the spacer and the snap ring are provided at the same axial position.

[0017] According to the above configuration 3, the axial length of the spacer seating surface can be minimized to provide the minimum spacer width that does not cause interference between the cage and the retaining ring on the outer ring side.

[0018] In any one of the above configurations 1 to 3, a configuration 4 can be adopted in which the spacer is made of a single part that is formed by pressing or coiling.

[0019] In any one of the above configurations 1 to 4, a configuration 5 can be adopted in which the clutch mechanism has an electromagnet, an armature that is attracted in the axial direction by the electromagnet, and a recoil spring that urges the armature in the axial direction away from the electromagnet, and is configured to switch between transmitting and cutting off the rotational torque in accordance with the axial movement of the armature by the electromagnet or the recoil spring.

[0020] In any one of the above configurations 1 to 5, configuration 6 can be adopted in which at least one of the inner ring and the outer ring is connected to a rotating shaft provided in a drive system or steering device of a vehicle, ship, or construction machine.

[0021] As described above, by adopting the above-described configuration 1, the present invention makes it possible to shorten the axial length of the inner ring while avoiding interference between the outer ring and the retainer that holds multiple engaging elements between the cam ring portion of the inner ring and the outer ring.

[0022] 1. A cross-sectional view showing a rotation transmission device according to an embodiment of the present invention when excited. A cross-sectional view showing a cut surface of line II-II in FIG. 1. An enlarged view of the vicinity of a flange portion of the cage in FIG. 1. A perspective view showing an example of a spacer according to an embodiment. A perspective view showing another example of a spacer according to an embodiment.

[0023] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A rotation transmission device according to an embodiment of the present invention will be described with reference to the accompanying drawings, FIGS. 1 to 3. FIG.

[0024] The rotation transmission device shown in Figures 1 and 2 comprises an inner ring 1, an outer ring 2 surrounding the inner ring 1, a rolling bearing 3 arranged between the inner ring 1 and the outer ring 2, and a clutch mechanism that transmits and interrupts rotation between the inner ring 1 and the outer ring 2.

[0025] Here, the direction along the central axis of relative rotation of the inner ring 1 and the outer ring 2 is referred to as the "axial direction," and the direction perpendicular to that central axis is referred to as the "radial direction." Furthermore, the circumferential direction centered on that central axis is referred to as the "circumferential direction." The axial direction corresponds to the left-right direction in Figure 1, and therefore, hereinafter, one axial direction will be simply referred to as the "left" in Figure 1, and the other axial direction opposite to one axial direction will be simply referred to as the "right" in Figure 1.

[0026] The inner ring 1 is connected to a rotating shaft 100 of another machine. The outer ring 2 is connected to a rotating shaft 101 of another machine. The other machine is, for example, a drive system of a vehicle, a ship, or a construction machine, and the rotating shafts 100, 101 are shafts that transmit power.

[0027] The inner ring 1 and the outer ring 2 are each made of a metal member formed into a hollow shaft. These metal members are made of, for example, forged steel, and their surfaces are hardened by heat treatment such as carburizing.

[0028] A joint portion is formed on the inner periphery of the inner ring 1 to be connected to the rotating shaft 100. A joint portion is formed on the right end of the inner periphery of the outer ring 2 to be connected to the rotating shaft 101. Each of these joint portions is a spline hole portion.

[0029] The rolling bearing 3 is a non-separable radial bearing having an inner raceway 3a, an outer raceway 3b, and a plurality of rolling elements 3c disposed between the inner and outer raceways 3a, 3b. Axial displacement of the inner and outer raceways 1, 2 is prevented by the plurality of rolling elements 3c engaging axially with the non-separable raceways 3a, 3b. In the illustrated example, the rolling bearing 3 is configured as a deep groove ball bearing.

[0030] The inner ring 1 has a bearing seat 1a that fits with the inner raceway ring 3a, a cam ring portion 1b that has a larger diameter than the bearing seat 1a, and a cylindrical portion 1c that has a smaller diameter than the cam ring portion 1b. That is, the cam ring portion 1b is located radially outward from the bearing seat 1a, and the cylindrical portion 1c is located radially inward from the cam ring portion 1b. The bearing seat 1a is located to the right of the cam ring portion 1b, and the cylindrical portion 1c is located to the left of the cam ring portion 1b.

[0031] A retaining ring 4 for preventing the inner raceway ring 3a from coming off relative to the inner race 1 is attached to a position adjacent to the right side of the bearing seat surface 1a.

[0032] The clutch mechanism is configured to be able to electromagnetically switch between an engaged state in which rotational torque is transmitted between the inner ring 1 and the outer ring 2, and a disengaged state in which transmission of rotational torque between the inner ring 1 and the outer ring 2 is interrupted.

[0033] The clutch mechanism includes a cam surface 1d formed on the outer periphery of the cam ring portion 1b, a cylindrical surface 2a formed on the inner periphery of the outer ring 2, an engaging element 5 arranged between the cam surface 1d and the cylindrical surface 2a, a retainer 6 that holds the engaging element 5, a centering spring 7 that is prevented from rotating by the inner ring 1 and the retainer 6, an electromagnet 8, an armature 9 that is prevented from rotating relative to the retainer 6 and is arranged so as to be movable in the axial direction, and a separation spring 10 that urges the armature 9 to the right, away from the electromagnet 8.

[0034] The cylindrical surface 2a extends circumferentially. The cam surface 1d forms a wedge space between itself and the cylindrical surface 2a. The wedge space gradually narrows from the circumferential center of the cam surface 1d toward both circumferential ends. That is, the radial distance between the cam surface 1d and the cylindrical surface 2a gradually decreases from the position of the engaging element 5 in FIG. 2 , which is located at the circumferential center of the cam surface 1d, toward one circumferential direction (counterclockwise in FIG. 2 ), and also gradually decreases from the position of the engaging element 5 toward the other circumferential direction (clockwise in FIG. 2 ). Multiple cam surfaces 1d are formed on the outer periphery of the inner ring 1 at intervals along the circumferential direction. That is, multiple wedge spaces are formed, and an engaging element 5 is disposed in each wedge space. Note that, although an example in which the cam surface 1d is configured as a single plane has been shown, the cam surface may be configured as a multiple-surface or single-curved surface.

[0035] As the cage 6 rotates relative to the inner ring 1, the engaging elements 5 engage with the cylindrical surface 2a and the cam surface 1d, thereby transmitting rotational torque between the inner ring 1 and the outer ring 2. The engaging elements 5 are formed in the shape of cylindrical rollers.

[0036] The cage 6 is an annular member having pockets formed at a plurality of locations in the circumferential direction to accommodate the engaging elements 5. The cage 6 is formed by press working.

[0037] The engaging element 5 is in circumferential contact with the retainer 6, so that the circumferential position of the engaging element 5 relative to the cam surface 1d is limited, and the engaging element 5 is forced to rotate together with the retainer 6.

[0038] The cage 6 can move coaxially with the inner ring 1 in the circumferential direction between a predetermined engagement position and a release position. The engagement position is a position where the engaging elements 5 are moved circumferentially from the circumferential center of the cam surface 1d to engage the cam surface 1d with the cylindrical surface 2a. The release position is a position where the engaging elements 5 are moved toward the circumferential center of the cam surface 1d to release the engagement of the engaging elements 5 with the cam surface 1d and the cylindrical surface 2a.

[0039] The cage 6 has a flange 6a located to the right of the engaging elements 5. The flange 6a is made of a metal plate extending in the radial direction. The flange 6a contributes to improving the rigidity of the cage 6.

[0040] The centering spring 7 is an elastic member that elastically holds the cage 6 in the release position. The centering spring 7 is elastically deformed by the relative rotation of the cage 6 with respect to the inner ring 1, and its restoring elasticity causes the cage 6 to return to its original position.

[0041] The centering spring 7 has extensions 7a extending radially outward from both circumferential ends of the arc-shaped spring portion. The arc-shaped spring portion of the centering spring 7 is passed through the outer periphery of the cylindrical portion 1c and is supported axially on the left end face of the cam ring portion 1b. The pair of extensions 7a pass through notches formed on the left side face of the cam ring portion 1b and are inserted into notches 6b formed in the left annular portion of the retainer 6. The pair of extensions 7a can press the notches of the cam ring portion 1b and the notches 6b of the retainer 6 in opposite circumferential directions. As a result, the centering spring 7 is capable of elastically holding the retainer 6 in the released position, while being prevented from rotating integrally with the inner ring 1 and is also prevented from rotating by the retainer 6.

[0042] The clutch mechanism has a spring pressing member 11 adjacent to the left side of the centering spring 7. The spring pressing member 11 is a ring member that is passed around the outer periphery of the cylindrical portion 1c. A retaining ring is attached to the outer periphery of the cylindrical portion 1c to restrict the spring pressing member 11 from moving leftward.

[0043] The armature 9 is an annular member fitted onto the outer periphery of the cylindrical portion 1c so as to be slidable in the axial direction. The armature 9 faces the electromagnet 8 in the axial direction.

[0044] The spring presser member 11 is prevented from rotating by the cage 6 and the armature 9. The spring presser member 11 is axially inserted into an engagement window 9a formed in the armature 9 and has an engagement protrusion 11a that fits into a notch 6b on the left side of the cage 6. Circumferential engagement is possible between the engagement window 9a and the engagement protrusion 11a and between the engagement protrusion 11a and the notch 6b throughout the axial reciprocating stroke of the armature 9, and this engagement allows the cage 6, armature 9, and the spring presser member 11 to move circumferentially together. Note that the rotation of the armature 9 and the cage 6 may be prevented by providing an engagement protrusion on the cage 6 that is inserted into the engagement window 9a of the armature 9, rather than by using a spring retaining ring.

[0045] The clutch mechanism has a rotor 12 that faces the electromagnet 8 and the armature 9 in the axial direction between them, and a rotor guide 13 that connects the rotor 12 to the outer ring 2. The rotor 12 and the rotor guide 13 can rotate integrally with the outer ring 2. A needle bearing 14 for supporting a rotating shaft 100 is fitted onto the inner periphery of the rotor 12.

[0046] The armature 9 is elastically held in a predetermined set position (the position shown in FIG. 1) by a separation spring 10, and is magnetically attracted from that set position by energizing the electromagnet 8. The set position is set at a position where the armature 9 abuts against the left end face of the cage 6 in the axial direction. Note that the set position of the armature 9 can also be set at a position where it abuts against a snap ring attached to the outer periphery of the cylindrical portion 1c.

[0047] The separation spring 10 is a spring member for biasing the armature 9 to the right. The separation spring 10 is disposed between a recess in the left side surface of the armature 9 and the annular right side surface of the rotor 12. The separation spring 10 stores energy when the armature 9 is moved leftward from the set position. The separation spring 10 is, for example, a wave washer-shaped or coil-shaped metal spring.

[0048] The electromagnet 8 switches from a non-excited state to an excited state when current is applied to the solenoid coil. When the electromagnet 8 enters the excited state, a magnetic circuit is generated that passes through the rotor 12 and the armature 9 and magnetically attracts the armature 9 to the right side surface of the rotor 12. Note that the rotor 12 and rotor guide 13 can be omitted if there is no concern about damage to the electromagnet 8 even if the armature 9 is attracted to the right end surface of the electromagnet 8, such as when the relative rotational speed of the inner ring 1 and the outer ring 2 is low.

[0049] The electromagnet 8 is fixed to the right side surface of an annular base plate 15. The base plate 15 is attached to a stationary part 102 provided on another machine. A retaining ring 16 is attached to the stationary part 102 to prevent the base plate 15 from coming off.

[0050] When the electromagnet 8 is not excited, the armature 9 is supported at a set position away from the rotor 12 by the separation spring 10, so that circumferential force cannot be transmitted between the rotor 12 on the outer ring 2 side and the armature 9. Therefore, the cage 6, which is prevented from rotating relative to the armature 9 and the inner ring 1, is elastically held by the centering spring 7 in a release position where the engaging element 5 does not engage with the cylindrical surface 2a of the outer ring 2 and the cam surface 1d of the inner ring 1. Therefore, regardless of whether the inner ring 1 or the outer ring 2 rotates counterclockwise or clockwise in FIG. 2 , the rotational torque is not transmitted between the inner ring 1 and the outer ring 2 via the engaging element 5, and the inner ring 1 and the outer ring 2 rotate relatively freely (freely). In other words, the clutch mechanism is in a disengaged state in which the transmission of rotational torque between the inner ring 1 and the outer ring 2 is interrupted. In this disengaged state, the rotation of the inner ring 1 is transmitted to the cage 6 via the centering spring 7, allowing the cage 6 and the engaging element 5 to rotate together. Furthermore, since the armature 9 is prevented from rotating relative to the cage 6, the armature 9 can also rotate together.

[0051] When at least one of the inner ring 1 and the outer ring 2 rotates and these rings 1 and 2 rotate relative to each other, the electromagnet 8 switches from a de-energized state to an energized state, causing the armature 9 to be attracted to the rotor 12 against the separation spring 10. Frictional resistance acting on the attracting surfaces of the rotor 12 and the armature 9 is applied via the spring retainer 11 as a circumferential force that moves the retainer 6 from the release position to the engagement position. This frictional resistance is set in advance to a value greater than the spring force of the centering spring 7. As a result, the centering spring 7 is pushed circumferentially by the retainer 6 and elastically deforms, causing the retainer 6 to rotate relative to the inner ring 1. This causes the retainer 6 to rotate relative to the inner ring 1, causing the engaging element 5 to be directed toward the narrow portion of the wedge space between the cylindrical surface 2 a of the outer ring 2 and the cam surface 1 d of the inner ring 1. As a result, the cage 6 moves to the engagement position, causing the engaging elements 5 to engage with the cam surface 1d of the inner ring 1 and the cylindrical surface 2a of the outer ring 2. This switches the rotation transmission device to an engaged state in which rotational torque is transmitted between the inner ring 1 and the outer ring 2.

[0052] In this engaged state, when the electromagnet 8 is switched to a de-energized state, the biasing force of the separation spring 10 separates the armature 9 from the rotor 12 and returns it to the set position, and in conjunction with this, the spring force of the centering spring 7 causes the retainer 6 to rotate relative to the inner ring 1 in the opposite direction to when it was engaged. As a result, the retainer 6 moves to the release position, and the engagement of the engaging element 5 with the cam surface 1d of the inner ring 1 and the cylindrical surface 2a of the outer ring 2 is released. This returns the rotation transmission device to the disengaged state.

[0053] As described above, to properly engage and disengage the cylindrical surface 2a of the outer ring 2 with the cam surface 1d of the inner ring 1, it is important that the position of the cage 6 is stable and that the inner ring 1 is coaxial with the cylindrical surface 2a. For this reason, the rolling bearing 3 is disposed close to the cam ring portion 1b, and the cage 6 is positioned in the axial and radial directions, preventing interference between the rolling bearing 3 and the cage 6.

[0054] 1 and 3, the outer raceway ring 3b of the rolling bearing 3 is restricted from moving leftward by a snap ring 17 attached to the inner periphery of the outer ring 2. The snap ring 17 protrudes between the cage 6 and the outer raceway ring 3b, and is adjacent to the left side surface of the outer raceway ring 3b.

[0055] The inner diameter surface of the flange 6a of the cage 6 is located between the cam ring portion 1b and the inner raceway ring 3a. The cam ring portion 1b has a restriction surface 1e that receives the flange 6a in the axial direction and a cage seat surface 1f that receives the flange 6a in the radial direction. The cage 6 is guided in the radial direction by the cage seat surface 1f on the inner diameter surface of the flange 6a. The flange 6a catches on the restriction surface 1e, restricting the cage 6 from moving leftward.

[0056] Furthermore, a spacer 18 is disposed adjacent to the right side surface (opposite the restricting surface 1e) of the flange portion 6a. The spacer 18 is ring-shaped and extends circumferentially. The inner ring 1 has a spacer seating surface 1g that receives the spacer 18 radially and a stepped surface 1h that receives the spacer 18 axially. The spacer 18 is positioned radially by fitting into the spacer seating surface 1g. The spacer 18 is sandwiched axially between the stepped surface 1h and the inner bearing ring 3a. Leftward movement of the spacer 18 is restricted by the stepped surface 1h. Leftward movement of the inner bearing ring 3a is restricted by the spacer 18 received on the stepped surface 1h. Rightward movement of the spacer 18 is restricted by the inner bearing ring 3a. Furthermore, even if the spacer 18 is pushed to the right by the flange 6 a of the retainer 6, which determines the set position of the armature 9, and the inner raceway ring 3 a is pushed to the right, the rightward movement of the inner raceway ring 3 a is restricted by the retaining ring 4.

[0057] By sandwiching the spacer 18 between the stepped surface 1h and the inner raceway ring 3a, the inner ring wall portion that protrudes between the spacer seating surface 1g and the inner raceway ring 3a is eliminated, shortening the axial length of the inner ring 1, while allowing the axial position of the rolling bearing 3 to be set at a position that ensures an axial gap between the snap ring 17 and the right side surface of the cage 6. In other words, if the spacer 18 were omitted and the inner raceway ring 3a were abutted against the stepped surface 1h, the snap ring 17 would interfere with the cage 6. If the snap ring 17 were omitted, there would be a concern that the outer ring 2 would shift to the right relative to the rolling bearing 3.

[0058] The spacer 18 and the retaining ring 17 are provided with the same width. The left side surface of the spacer 18 and the left side surface of the retaining ring 17 face each other in the radial direction. Therefore, the spacer 18 and the retaining ring 17 are provided at the same axial position. In other words, it is only necessary to ensure a minimum axial distance between the step surface 1h and the inner raceway ring 3a, which is sufficient for the arrangement of the retaining ring 17, and the width of the spacer seating surface 1g can be reduced.

[0059] The spacer seating surface 1g is formed into a cylindrical surface extending in the circumferential direction. The spacer seating surface 1g and the bearing seating surface 1a are formed into the same plane that is continuous in the axial direction.

[0060] Forming a protruding inner ring wall between the spacer seating surface and the inner raceway ring 3a is not desirable because it would increase the axial length of the inner ring. It is possible to make the diameter of the spacer seating surface larger than the diameter of the bearing seating surface 1a. In this case, a step would occur between the spacer seating surface and the bearing seating surface 1a, making the inner ring shape more complex than the inner ring 1.

[0061] The ring shape of the spacer 18 may extend in the circumferential direction within a range that allows the spacer 18 to be positioned radially by fitting with the spacer seating surface 1g. As shown in FIG. 4, the ring shape may be a circular annular plate that is continuous around the entire circumferential direction, or as shown in FIG. 5, the ring shape may be an arcuate plate that extends in the circumferential direction.

[0062] The spacer 18 shown in Fig. 4 is made of a single part that has been pressed. The spacer 18 shown in Fig. 5 is made of a single part that has been coiled. If the diameter of the spacer 18 is large enough to be formed by coiling, it can be made by coiling. If the diameter of the spacer 18 is small enough to be formed by coiling, it can be made by pressing. Using a spacer 18 made by coiling eliminates the need for mold costs, and therefore the spacer 18 can be manufactured more inexpensively.

[0063] As described above, the rotation transmission device shown in Figures 1 to 3 comprises an inner ring 1, an outer ring 2 surrounding the inner ring 1, a rolling bearing 3 arranged between the inner ring 1 and the outer ring 2, and a clutch mechanism for transmitting and blocking rotational torque. The rolling bearing 3 has an inner raceway 3a, an outer raceway 3b, and a plurality of rolling elements 3c arranged between the inner and outer raceways 3a, 3b. The inner ring 1 has a bearing seat 1a that fits into the inner raceway 3a, and a bearing seat 1b that is provided with a larger diameter than the bearing seat 1a. The clutch mechanism has a plurality of engaging elements 5 arranged at predetermined intervals in the circumferential direction between the cam ring portion 1b and the outer ring 2, and a retainer 6 that holds these engaging elements 5. The retainer 6 has a flange portion 6a that extends radially between the cam ring portion 1b and the inner raceway ring 3a, and the cam ring portion 1b has a cam surface 1d that contacts the engaging elements 5, a regulating surface 1e that receives the flange portion 6a in the axial direction, and a retainer seat surface 1f that receives the flange portion 6a in the radial direction.

[0064] This rotation transmission device particularly further includes a spacer 18 adjacent to the anti-restriction surface 1e side of the rib portion 6a, the spacer 18 being ring-shaped, the inner ring 1 having a spacer seating surface 1g that radially receives the spacer 18, the cam ring portion 1b having a stepped surface 1h that axially receives the spacer 18, and the spacer 18 being sandwiched axially between the stepped surface 1h and the inner raceway 3a, so that the ring-shaped spacer 18 is positioned radially by the spacer seating surface 1g and is positioned axially by the stepped surface 1h and the inner raceway 3a. Therefore, the cage 6 is positioned axially by the restriction surface 1e that axially receives the rib portion 6a and the spacer 18 that is restricted by the inner raceway 3a at a position adjacent to the anti-restriction surface 1e side of the rib portion 6a. Because no groove such as a retaining ring groove is used to position the spacer 18, there is no groove shoulder sandwiched between the spacer 18 and the inner raceway ring 3a, thereby reducing the axial length of the inner ring 1. Furthermore, because the spacer 18 adjacent to the flange 6a is sandwiched between the stepped surface 1h and the inner raceway ring 3a, it is possible to ensure an appropriate axial distance between the outer raceway ring 3b and the cage 6, and interference between the cage 6 and the outer ring 2 side is avoided.

[0065] In this way, this rotation transmission device can shorten the axial length of the inner ring 1 while avoiding interference between the retainer 6, which holds multiple engaging elements 5 between the cam ring portion 1b of the inner ring 1 and the outer ring 2, and the outer ring 2 side.

[0066] Furthermore, in this rotation transmission device, the spacer seat surface 1g and the bearing seat surface 1a are formed on the same plane that is continuous in the axial direction, so there is no step between the spacer seat surface 1g and the bearing seat surface 1a, and the shape of the inner ring 1 is prevented from becoming complicated.

[0067] Furthermore, in this rotation transmission device, the retaining ring 17 adjacent to the outer raceway 3b is attached to the outer raceway 2 between the retainer 6 and the outer raceway 3b, and the spacer 18 and the retaining ring 17 are provided at the same axial position, so that the width of the spacer 18 can be set to the minimum possible value that prevents interference between the retainer 6 and the retaining ring 17 on the outer raceway 2 side, and the axial length of the spacer seat surface 1g can be minimized.

[0068] Although this rotation transmission device has been shown as being applied to a rotating shaft provided in the drive system of a vehicle, ship, construction machine, etc., it can also be modified to a rotation transmission device for braking purposes that interrupts the transmission of rotation from a rotating shaft, such as a steering lock for the steering device of such construction machine, etc. In this case, a rotating shaft such as a steering shaft is connected to one of the inner or outer ring, and the other is prevented from rotating relative to a stationary part provided in the other machine.

[0069] In addition, although this rotation transmission device has been shown as an example in which the cylindrical surface 2a is formed on the outer ring 2 and the cam surface 1d is formed on the inner ring 1, it is also possible to form the cylindrical surface on the inner ring and the cam surface on the inner peripheral part of the outer ring. Also, sprags may be used as the engaging elements, and the tilting position of the sprags may be controlled by the relative rotation of the cage.

[0070] Furthermore, although this rotation transmission device has been exemplified as an excitation-operated type in which the clutch mechanism is arranged to transition to a state in which rotational torque can be transmitted when the electromagnet 8 is excited, it is also possible to change the clutch mechanism to a non-excitation-operated type in which the clutch mechanism is arranged to transition to a state in which rotational torque can be transmitted when the electromagnet is not excited.

[0071] The embodiments disclosed herein should be considered to be illustrative in all respects and not restrictive. Therefore, the scope of the present invention is defined by the claims rather than the above description, and it is intended to include all modifications within the meaning and scope of the claims.

[0072] DESCRIPTION OF SYMBOLS 1 Inner ring 1a Bearing seat surface 1b Cam ring portion 1d Cam surface 1e Restricting surface 1f Cage seat surface 1g Spacer seat surface 1h Step surface 2 Outer ring 2a Cylindrical surface 3 Rolling bearing 3a Inner raceway ring 3b Outer raceway ring 3c Rolling element 5 Engagement element 6 Cage 6a Flange portion 7 Centering spring 8 Electromagnet 9 Armature 10 Separation spring 17 Retaining ring 18 Spacer 100, 101 Rotating shaft

Claims

1. A rotation transmission device comprising an inner ring, an outer ring surrounding the inner ring, a rolling bearing arranged between the inner ring and the outer ring, and a clutch mechanism for transmitting and interrupting rotational torque, wherein the rolling bearing has an inner raceway, an outer raceway, and a plurality of rolling elements arranged between the inner and outer raceways, the inner ring has a bearing seat that fits with the inner raceway, and a cam ring portion that is larger in diameter than the bearing seat surface, the clutch mechanism has a plurality of engaging elements arranged at predetermined intervals in the circumferential direction between the cam ring portion and the outer ring, and a retainer that retains these engaging elements, the retainer having a flange that extends radially between the cam ring portion and the inner raceway, and the cam ring portion having a cam surface that contacts the engaging elements, a restriction surface that receives the flange in the axial direction, and a retainer seat surface that receives the flange in the radial direction, further comprising a spacer on the opposite side of the restriction surface of the flange, a rotation transmission device, characterized in that the spacer is ring-shaped, the inner ring has a spacer seat surface that receives the spacer in a radial direction, the cam ring portion has a stepped surface that receives the spacer in an axial direction, and the spacer is sandwiched in the axial direction between the stepped surface and the inner raceway ring.

2. A rotation transmission device according to claim 1, wherein the spacer seating surface and the bearing seating surface are formed as a single plane that is continuous in the axial direction.

3. A rotation transmission device as set forth in claim 1 or 2, wherein a snap ring is attached to the outer ring between the cage and the outer raceway ring, and the spacer and the snap ring are provided at the same axial position.

4. A rotation transmission device according to any one of claims 1 to 3, wherein the spacer is made of a single part that is formed by pressing or coiling.

5. A rotation transmission device as claimed in any one of claims 1 to 4, wherein the clutch mechanism has an electromagnet, an armature that is attracted in the axial direction by the electromagnet, and a recoil spring that urges the armature in the axial direction away from the electromagnet, and is configured to switch between transmitting and cutting off the rotational torque in response to axial movement of the armature by the electromagnet or the recoil spring.

6. A rotation transmission device according to any one of claims 1 to 5, wherein at least one of the inner ring and the outer ring is connected to a rotating shaft provided in a drive system or steering device of a vehicle, ship or construction machine.

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