Title of Invention

ONE WAYCLUTCH OF ROTATION OPERATIVE TYPE

Abstract

The present invention provides a one-way clutch of rotation operative type, comprising an outer race having an inner peripheral cylindrical surface, an inner race on which a cam surface is formed, a rolling member for transmitting torque between the outer race and the inner race, a biasing spring for biasing the rolling member, and a weight member for urging the rolling member toward an engagement direction while resisting a biasing force of the biasing spring by a centrifugal force, and wherein a cage for containing the rolling member, weight member and biasing spring is provided between the outer race and the inner race and the cage is provided with a weight member acting surface for guiding a movement of the weight member.

Full Text

ONE-WAY CLUTCH OF ROTATION OPERATIVE TYPE BACKGROUND OF THE INVENTION Field of the Invention The present invention relates to a one-way clutch of rotation operative type used in automatic motor cycles or snow mobiles and acting as a one-way clutch when number of rotation exceeds a predetermined value. Related Background Art In general, a one-way clutch includes outer and inner races which are rotated relative to each other and is designed so that rotational torque is transmitted only in one direction by engaging sprags or rollers for transmitting the torque between the outer race and the inner race with a cam surface provided on a track surface of the outer or inner race and an idle rotation is performed in a reverse direction. Among such one-way clutches, a one-way clutch in which rollers are disposed in pockets (recess portions) provided in the inner or outer race and rotation is locked by a wedging action achieved by engaging the rollers with wedge portions in the pockets, depending upon a rotational direction, is known. For example, Japanese Patent Publication No. 53-8019 (1978) discloses an arrangement in which rollers are disposed in recess portions provided in an outer race and, when the outer race is rotated in a clockwise direction, the rollers are locked in the recess portions by a wedging action, thereby locking a rotation of the outer race with respect to an inner race. Further, Japanese Patent Application Laid-open No. 52-100045 (1977) discloses an arrangement in which a roller and an auxiliary roller are disposed between an outer race and an input coupling so that, number of rotation exceeds a predetermined value, the auxiliary roller is urged against the roller by a centrifugal force. In this case, when a rotation is caused by the urging force in a predetermined direction, the roller can be locked by a wedging action, thereby achieving a one-way clutch function. The arrangement disclosed the above-mentioned Japanese Patent Publication No. 53-8019 is a general or normal one-way clutch using the rollers and this arrangement is not designed so that the locking is achieved in accordance with the number of rotation. Further, the above-mentioned Japanese Patent Application Laid-open No. 52-100045 discloses the arrangement in which the locking is achieved in accordance with the number of rotation. However, since an elongated hole for determining an operating range of the auxiliary roller is provided in a member different from the outer race, it is difficult to obtain desired dimensional accuracy of the apparatus and the number of parts is increased. Further, since it is feared that the auxiliary roller is caught by the elongated hole, it is required to provide a plate for urging the roller or a holding and carrying member, with, since the result that an installation space for a spring is required, a reduction in a diameter of the apparatus is limited. In addition, in a case where a coil spring is used as the spring for biasing the roller, it is difficult to set spring constant of the coil spring to a smaller value within a limited space, and the coil spring may be expensive in comparison with an accordion spring. SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a one-way clutch of rotation operative type in which the number of parts can be reduced and which is inexpensive and in which spring constant can be set to a smaller value and dimensional accuracy can easily be attained and a weight member may not be caught and a design can be achieved within a limited space. To achieve the above object, the present invention provides a one-way clutch of rotation operative type, comprising an outer race having an inner peripheral cylindrical surface, an inner race on which a cam surface is formed, a rolling member for transmitting torque between the outer race and the inner race, a biasing spring for biasing the rolling member, and a weight member for urging the rolling member toward an engagement direction while resisting a biasing force of the biasing spring by a centrifugal force, and wherein a cage for containing the rolling member, weight member and biasing spring is provided between the outer race and the inner race and the cage is provided with a weight member acting surface for guiding a movement of the weight member. Further, the present invention provides a oneway clutch of rotation operative type, comprising an outer race having an inner peripheral cylindrical surface, an inner race on which a cam surface is formed, a rolling member for transmitting torque between the outer race and the inner race, a biasing spring for biasing the rolling member, and a weight member for urging the rolling member toward an engagement direction while resisting a biasing force of the biasing spring by a centrifugal force, and wherein the inner race is provided at its outer peripheral surface with a recess portion for partially housing the weight member. Further, the present invention provides a oneway clutch of rotation operative type, comprising an outer race having an inner peripheral cylindrical surface, an inner race on which a cam surface is formed, a rolling member for transmitting torque between the outer race and the inner race, a biasing spring for biasing the rolling member, and a weight member for urging the rolling member toward an engagement direction while resisting a biasing force of the biasing spring by a centrifugal force, and wherein a cage for containing the rolling member, weight member and biasing spring or a side plate for limiting axial movements of the rolling member, weight member and biasing spring is provided between the outer race and the inner race and the cage or the side plate is provided with an axial through-hole. Further, the present invention provides a oneway clutch of rotation operative type, comprising an outer race having an inner peripheral cylindrical surface, an inner race on which a cam surface is formed, a rolling member for transmitting torque between the outer race and the inner race, a biasing spring for biasing the rolling member, and a weight member for urging the rolling member toward an engagement direction while resisting a biasing force of the biasing spring by a centrifugal force, and wherein the weight member is contacted with the inner race along a straight line. According to the present invention as mentioned above, the following effect can be obtained. Since the biasing spring biases the rolling member a non-engagement direction with respect to the cam surface and the weight member for urging the rolling member toward the engagement direction with respect to the cam surface while resisting the biasing force of the biasing spring by the centrifugal force is provided, a one-way clutch of rotation operative type in which the number of parts can be reduced and which is inexpensive and in which spring constant can be set to a smaller value and dimensional accuracy can easily be attained and the weight member may not be caught and a design can be achieved within a limited space. Further, the following special effects can be obtained. According to the present invention, the smooth operation of the weight member can be achieved. Further, the manufacturing cost can be reduced. For example, in a case where the pocket is provided in the inner race, although a portion corresponding to the pocket must be removed by polishing, cutting and/or wire cut, since the portion corresponding to the pocket has great volume, the working time becomes great and deformation due to heat treatment is apt to occur. Further, a range of the cam surface requiring high accuracy can be reduced. Further, a larger weight member can be housed. A lubricating ability of the one-way clutch can be enhanced. Further, the working can be facilitated and productivity is enhanced. According to the arrangement of the present invention, excessive movement of the rolling member in an inoperative condition can be suppressed. The working can be facilitated and productivity is enhanced. Balance of strength of the cage can be achieved. In this specification, a term "rotation operative type" means that the function of the oneway clutch can be achieved positively in the rotational range exceeding the predetermined number of rotation. However, the function of the one-way clutch may be achieved in a low speed rotational range and/or a rotational range smaller than the predetermined number of rotation. Further, the "predetermined number of rotation" is determined voluntarily in accordance with mass of the weight member, a distance between the weight member and a center of the inner race and an inclination angle of the weight member acting surface. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a front view of a one-way clutch of rotation operative type according to a first embodiment of the present invention; Fig. 2 is a schematic view of a pocket portion, looked at from an outer diameter side of the first embodiment of the present invention; Fig. 3 is an axial sectional view of the oneway clutch of rotation operative type according to the first embodiment of the present invention; Fig. 4 is a view showing a roller and a weight member in a non-rotation condition and during a low speed rotation, in the first embodiment of the present invention; Fig. 5 is a view showing the roller and the weight member in an operating condition (engagement condition), in the first embodiment of the present invention; Fig. 6 is a front view of a one-way clutch of rotation operative type according to a second embodiment of the present invention; Fig. 7 is an axial sectional view of the oneway clutch of rotation operative type according to the second embodiment of the present invention; Fig. 8 is a view showing a roller and a weight member in a non-rotation condition and during a low speed rotation, in the second embodiment of the present invention; Fig. 9 is a view showing the roller and the weight member in an operating condition (engagement condition), in the second embodiment of the present invention; Fig. 10 is a development view of a cage (first plate) in the second embodiment of the present invention; Fig. 11 is a development view of a cage (second plate) in the second embodiment of the present invention; Fig. 12 is a schematic view of a pocket portion, looked at from an outer diameter side of the second embodiment of the present invention; and Fig. 13 is a front view an accordion spring attaching portion in the second^ embodiment of the present invention. DESCRIPTION OF THE PREFERRED EMBODIMENTS Now, embodiments of the present invention will be fully explained with reference to the accompanying drawings. In the drawings, same elements are designated by the same reference numerals. (First embodiment) First of all, a first embodiment of the present invention will be explained. Fig. 1 is a front view of a one-way clutch 30 of rotation operative type according to the first embodiment and Fig. 2 is a schematic view of a pocket portion, looked at from an outer diameter side of the first embodiment. A roller 37, a weight member 38 and an accordion spring 35 which constitute a one-way clutch portion are housed and held in a window portion 4 3 (refer to Figs. 2 and 4) provided in a cage 32. A substantially annular cage 32 disposed between an outer race 3 and an inner race 2 is a cage body and a substantially annular support plate 34 is provided at an axial end of the cage 32. The support plate 34 is secured to the cage 32 by a cage joining portion 33. In each of the window portions 43 equidistantly arranged in a circumferential direction of the cage 32, there are housed the accordion spring 35 for biasing the roller 37 from an outer race 3 side, the roller 37 for transmitting torque between the outer race 3 and the inner race 2, and the weight member 38 for acting on the roller 37 to urge the roller 37 toward an engagement direction. When the weight member 38 does not act on the roller, a part of the weight member 38 is housed in a recess portion 31 provided in an outer peripheral surface of the inner race 2. A radius of an arc describing a bottom surface of the recess portion 31 is greater than a radius of the weight member 38 and the weight member 38 is contacted with the recess portion 31 along a straight line. With this arrangement, the weight member is not caught by the recess portion 31 to move smoothly, thereby enhancing an operation of the apparatus. Recessed portions 36 each having a laid U-shaped radial section are provided in the cage 32 and an end of the accordion spring 35 opposite to its end for biasing the roller 37 is fitted in and held by the recess portion 36 (refer to Fig. 4). As can be seen from Fig. 2, the window portion 43 of the cage 32 is formed by drilling the cage 32 in an axial direction while remaining a wall portion. An axial open end of the window 32 is closed by the support plate 34. Accordingly, the accordion spring 35, roller 37 and weight member 38 housed in the window portion 43 are held axially by the wall of the cage 32 and the support plate 34 and held radially by the outer race 3 and the inner race 2 so that these elements can not be dislodged from the window portion 43. Fig. 3 is an axial sectional view of the oneway clutch 30 of the rotation operative type. It can be seen that the support plate 34 is secured with respect to the cage 32 by the cage joining portion 33. Further, it can be seen that the roller 37 has a small clearance between the wall portion of the cage 32 and the support plate 34 and is supported in an axial direction. Next, the operation of the one-way clutch 30 of rotation operative type according to the first embodiment will be explained with reference to Figs. 4 and 5. Fig. 4 is a view showing the roller and the weight member in a non-rotation condition and during a low speed rotation, in the first embodiment, and Fig. 5 is a view showing the roller and the weight member in an operating condition (engagement condition), in the first embodiment. Now, the arrangement according to the first embodiment will be described in more detail with reference to Fig. 4. The cage 32 includes a plurality of protruded portions 44 fitted into a plurality of recessed grooves 45 provided in an outer peripheral surface of the inner race 2 equidistantly disposed along a circumferential direction thereof. Since the protruded portions 44 are fitted into the recessed grooves 45, the cage 32 and the inner race 2 can not rotate relative to each other. A weight member acting surface 40 is formed on one of side surfaces of the window portion 43 of the cage 32. When weight member 38 is subjected to a centrifugal force, the weight member is shifted toward an outer diameter side along the weight member acting surface to contact and urge the roller 37, thereby shifting the roller 37 up to the engagement position. Further, a roller locking portion (rolling member locking portion) 42 for limiting an operating range of the roller 37 toward the weight member 38 is provided at the outer diameter side. In the illustrated embodiment, although the weight member acting surface 40 and the roller locking portion 42 are continuously provided, they may not necessarily be continuous. The recess portion 31 for partially housing the weight member 38 is provided in the outer peripheral surface of the inner race 2 at a position opposed to the weight member acting surface 40 and the roller locking portion 4 2 of the cage 32 and a cam surface 47 as a torque transmitting surface for the roller 37 is formed in adjacent to the recess portion 31. In the illustrated embodiment, although the recess portion and the cam surface 47 are continuously provided, they may not necessarily be continuous. The reason why the recess portion 31 partially contains the weight member 38 is to minimize the operating range of the weight member 38. As shown in Fig. 4, in a non-rotation condition and during a low speed rotation (range), the weight member 38 is positioned at an inner diameter side of the recess portion 31 and the roller 37 is urged against the roller locking portion 42 by the accordion spring 35. Thereafter, the inner race 2 is rotated. When the rotational speed of the inner race reaches a high speed greater than the predetermined number of rotation, the weight member 38 subjected to the centrifugal force is shifted toward the outer diameter side, thereby shifting the roller 37 to the engagement position of the cam surface 47. In this condition, when the inner race 2 is rotated with respect to the outer race 3 in an anti-clockwise direction in a preceding manner, the torque is transmitted. This operating condition is shown in Fig. 5. (Second embodiment) Next, a second embodiment of the present invention will be explained with reference to Figs. 6 to 13. In the second embodiment, a positional relationship between the weight member 38, roller 37 and accordion spring 35 and operations of these elements are substantially the same as those in the first embodiment. In the second embodiment, a shape of a cage greatly differs from that in the first embodiment. Now, the cage used in the second embodiment will be explained with reference to Figs. 10 and 11. Fig. 10 is a development view of a first plate 60 of a cage 50 according to the second embodiment and Fig. 11 is a development view of a second plate 70 of the cage 50 according to the second embodiment. In the second embodiment, the cage 50 is formed as the first and second plates by blanking a plate-shaped steel plate. Fig. 10 is a development view of the first plate. The first plate 60 includes a plurality of protruded portions extending radially from a substantially annular body 66. Each protruded portion is a first column portion 51 in which a hole 62 for attaching the accordion spring 35 is formed. A plurality of holes 67 communicated with the pockets or window portions of the cage and communicated with exterior are formed in an outer periphery of the body 66. Metallic powder and foreign matters generated in the one-way clutch or dirt in lubricating oil can be discharged to the exterior through the holes 67. The holes may be formed in a side plate (not shown) rather than the cage. Further, the number of holes may be selected optionally and the plural holes may not necessarily be provided. Clamping holes 64 for connection to the second plate 70 which will be described later are formed in the body 66. Further, two engagement tongues 65 for securing the cage 50 to the inner race 2 are provided at an inner diameter side of the body 66. It is preferable that the protruded portions, clamping holes 64 and engagement tongues 65 are equidistantly disposed along a circumferential direction. The engagement tongues 65 are fitted in recessed grooves 54 of the inner race 2 to secure the entire cage to the inner race 2. Fig. 11 is a development view of the second plate 70. The second plate 70 includes a plurality of protruded portions extending radially from a substantially annular body 75. Each protruded portion comprises a second column portion 72 and a caulking projection 71, and a weight member acting surface 52 (described later) is formed between the second column portion 72 and the projection 71. Two engagement tongues 74 for securing the cage 50 to the inner race 2 are provided at an inner diameter side of the body 75. It is preferable that the protruded portions and the engagement tongues 74 are equidistantly disposed along a circumferential direction. The cage 50 according to the second embodiment (refer to Figs. 6 and 7) is obtained by bending the first plate 60 and the second plate 70 to desired shapes and then by joining both plates together. Next, a one-way clutch 80 of rotation operative type according to the second embodiment will be fully explained with reference to Figs. 6 to 13. Fig. 6 is a front view of the one-way clutch 80 of rotation operative type according to the second embodiment and Fig. 7 is an axial sectional view of the one-way clutch 80 of rotation operative type according to the second embodiment. Further, Fig. 8 is a view showing the roller and the weight member in a non-rotation condition and during a low speed rotation, in the second embodiment, and Fig. 9 is a view showing the roller and the weight member in an operating condition (engagement condition), in the second embodiment. In Fig. 6, the cam surface 47 provided on the outer peripheral surface of the inner race 2 is substantially the same as that in the first embodiment. The second embodiment differs from the first embodiment in the point that the operating surface for the weight member 38 is formed in the protruded portion provided on the first or second plate constituting the cage 50. By fitting the caulking projections 71 of the second plate 70 into the clamping holes 64 of the first plate 60 and by performing the caulking, the cage 50 is formed via jointed portions 53. The protruded portions of the second plate 70 are bent to be positioned at the inner peripheral side of the outer race 3, thereby forming the weight member acting surfaces 52 having predetermined inclination with respect to the radial direction. Fig. 7 is an axial sectional view of Fig. 6. It can be seen that the cage 50 comprises the first plate 60 and the second plate 70. Next, an operation of a one-way clutch 80 according to the second embodiment will be explained with reference to Figs. 8 and 9. The fundamental operation is the same as that in the first embodiment. As shown in Fig. 8, in the non-rotation condition and during the low speed rotation, the weight member 38 is positioned at the inner diameter side of the recess portion 31 and the roller 37 is urged toward a non-engagement direction by the accordion spring 35. Thereafter, the inner race 2 is rotated. When the rotational speed of the inner race reaches a high speed greater than the predetermined number of rotation, the weight member 38 subjected to the centrifugal force is shifted toward the outer diameter side along the weight member acting surface 52, thereby shifting the roller 37 to the engagement position of the cam surface 47. In this condition, when the inner race 2 is rotated with respect to the outer race 3 in an anti-clockwise direction in a preceding manner, the torque is transmitted. This operating condition is shown in Fig. 9. A relationship between the cage 50 and the accordion spring 35 is as follows. Fig. 12 is a schematic view of the pocket portion, looked at from the outer diameter side in the second embodiment. Fig. 13 is a front view of the accordion spring attaching portion in the second embodiment. As shown in Fig. 12, a distal end of the accordion spring 35 is an abutment portion 58 for urging the roller 37 and a proximal end of the accordion spring is an attaching portion 57. The accordion spring 35 is secured to the cage 50 by pinching the first column portion 51 by means of the attaching portion 57. Further, the accordion spring 35 is secured further firmly by engaging a tongue 56 provided on the attaching portion with the hole 62. An attaching condition of the attaching portion 57 of the accordion spring 35 is shown in Fig. 13 and it can be seen that the tongue 56 provided on the distal end of the attaching portion 57 is fitted into the hole 62 of the first plate 60 of the cage. According to the second embodiment, a manufacturing cost can be reduced. Incidentally, although it is considered that the weight member can be made of steel, copper, steel alloy, aluminum or synthetic resin, in a case where the weight member is made of material having high specific weight such as steel, since the centrifugal force acting on a unit area becomes great, even when the apparatus is compact, during the low speed rotation, engagement can be achieved. Further, the diameter of the weight member 38 can be reduced. In the above-mentioned embodiments, while an example that the cylindrical roller is used as the rolling member disposed within the pocket was explained, a sphere may be used as the rolling member. Further, the weight member may be a sphere rather than the cylindrical roller. Further, regarding a combination of the rolling member and the weight member, both of these members may be rollers or spheres, or one of these members may be a roller and the other may be a sphere. Further, in the above-mentioned embodiments, although the plurality of pockets are provided along the circumferential direction, the number of pockets can be varied with required torque capacity and the like, and, for example, four or six pockets may be provided other than eight pockets. However, regardless of the number of pockets, it is preferable that the pockets are disposed equidistantly along the circumferential direction. Further, in the first and second embodiments, while an example that diameters of the roller and the weight member are substantially the same was explained, it is not necessary that such diameters are the same, and the diameters can be set voluntarily in accordance with a usage condition (for example, range of number of rotation in the operative condition). WHAT IS CLAIMED IS: 1. A one-way clutch of rotation operative type, comprising: an outer race having an inner peripheral cylindrical surface; an inner race on which a cam surface is formed; a rolling member for transmitting torque between said outer race and said inner race; a biasing spring for biasing said rolling member; and a weight member for urging said rolling member toward an engagement direction while resisting a biasing force of said biasing spring by a centrifugal force; and wherein a cage for containing said rolling member, said weight member and said biasing spring is provided between said outer race and said inner race and said cage is provided with a weight member acting surface for guiding a movement of said weight member. 2. A one-way clutch of rotation operative type, comprising: an outer race having an inner peripheral cylindrical surface; an inner race on which a cam surface is formed; a rolling member for transmitting torque between said outer race and said inner race; a biasing spring for biasing said rolling member; and a weight member for urging said rolling member toward an engagement direction while resisting a biasing force of said biasing spring by a centrifugal force; and wherein said inner race is provided at its outer peripheral surface with a recess portion for partially housing said weight member. 3. A one-way clutch of rotation operative type, comprising: an outer race having an inner peripheral cylindrical surface; an inner race on which a cam surface is formed; a rolling member for transmitting torque between said outer race and said inner race; a biasing spring for biasing said rolling member; and a weight member for urging said rolling member toward an engagement direction while resisting a biasing force of said biasing spring by a centrifugal force; and wherein a cage for containing said rolling member, said weight member and said biasing spring or a side plate for limiting axial movements of said rolling member, said weight member and said biasing spring is provided between said outer race and said inner race and said cage or said side plate is provided with an axial through-hole. 4. A one-way clutch of rotation operative type, comprising: an outer race having an inner peripheral cylindrical surface; an inner race on which a cam surface is formed; a rolling member for transmitting torque between said outer race and said inner race; a biasing spring for biasing said rolling member; and a weight member for urging said rolling member toward an engagement direction while resisting a biasing force of said biasing spring by a centrifugal force; and wherein said weight member is contacted with said inner race along a straight line. 5. A one-way clutch of rotation operative type according to any one of claims 2 to 4, wherein a cage for containing said rolling member, said weight member and said biasing spring is provided between said outer race and said inner race and said cage is provided with a weight member acting surface for guiding a movement of said weight member. 6. A one-way clutch of rotation operative type according to claim 1, 3 or 4, wherein a recess portion for partially containing said weight member is provided in an outer peripheral surface of said inner race. 7. A one-way clutch of rotation operative type according to claim 1, 2 or 4, wherein a cage for containing said rolling member, said weight member and said biasing spring or a side plate for limiting axial movements of said rolling member, said weight member and said biasing spring is provided between said outer race and said inner race and said cage or said side plate is provided with an axial through-hole. 8. A one-way clutch of rotation operative type according to any one of claims 1 to 3, wherein said weight member is contacted with said inner race along a straight line. 9. A one-way clutch of rotation operative type according to any one of claims 1, 3 and 5 to 8, wherein said cage is formed by bending a metallic plate, 10. A one-way clutch of rotation operative type according to any one of claims 1, 3 and 5 to 9, wherein said cage is provided with a rolling member locking portion for limiting an operating range of said rolling member. 11. A one-way clutch of rotation operative type according to any one of claims 1, 3 and 5 to 10, wherein said cage is provided with a through-hole. 12. A one-way clutch of rotation operative type according to any one of claims lf 3 and 5 to 11, wherein said cage comprises first and second plates having substantially annular portions, and one or both of said plates is provided with a first column portion for attaching said biasing spring, a second column portion for forming said weight member and an engagement tongue. 13. A one-way clutch of rotation operative type according to claim 12, wherein one of said first and second plates is provided with said first column portion and the other is provided with said second column portion, and both of said first and second plates are provided with sand engagement tongues. 14. A one-way clutch of rotation substantially as herein described with reference to the accompanying drawings.

Documents:

110-che-2004-abstract.pdf

110-che-2004-claims duplicate.pdf

110-che-2004-claims original.pdf

110-che-2004-correspondnece-others.pdf

110-che-2004-correspondnece-po.pdf

110-che-2004-description(complete) duplicate.pdf

110-che-2004-description(complete) original.pdf

110-che-2004-drawings.pdf

110-che-2004-form 1.pdf

110-che-2004-form 19.pdf

110-che-2004-form 26.pdf

110-che-2004-form 3.pdf

110-che-2004-form 5.pdf