JP2019002464A - Pulley unit - Google Patents

Abstract

To provide a pulley unit which is reducible in a length in an axial direction, and can suppress the leakage of a lubricant.SOLUTION: A pulley unit has: a hub rotating with a rotating axis as a center; a pulley supported to the hub via a slide bearing; a first cam plate rotating integrally with the hub; a second cam plate which rotates integrally with the pulley, and can move to a direction along the rotating axis; rolling bodies contacting with the first cam plate and the second cam plate; an elastic member which is deformed accompanied by the movement of the second cam plate in a direction along the rotating axis; and a support member arranged at a side opposite to a side of the second cam plate with respect to the elastic member in the direction along the rotating axis. The slide bearing has a circular disc shape continuing over the whole periphery, is arranged at an external peripheral face of the support member, and sandwiched in the direction along the rotating axis by the support member arranged at one end side of the slide bearing and a member different from the support member arranged at the other end side of the slide bearing.SELECTED DRAWING: Figure 5

Description

  The present invention relates to a pulley unit mainly used for an auxiliary machine of an engine.

  The rotation of the crankshaft of the engine is transmitted to an auxiliary machine such as an alternator via a belt. The belt transmits the rotation of the pulley attached to the crankshaft to the pulley attached to the alternator. As the capacity of the alternator increases and the number of cylinders of the engine decreases, fluctuations in belt tension increase. In order to prevent slippage between the belt and the pulley, it is necessary to increase the initial tension of the belt. However, when the initial tension of the belt is increased, the belt is easily damaged.

  On the other hand, for example, Patent Literature 1 discloses a technique for suppressing fluctuations in belt tension. In the pulley unit described in Patent Document 1, a coil spring is provided between the pulley and the hub. When the pulley rotates, the coil spring transmits torque to the hub while elastically deforming in a direction in which the diameter changes. Thereby, the fluctuation | variation of belt tension is suppressed.

  Moreover, in the pulley unit described in Patent Document 1, a bearing is provided between the pulley and the hub so that the pulley and the hub can rotate relative to each other. For example, on one end side of the hub, a rolling bearing is provided immediately below the belt where the load from the belt is large, and on the other end side, a sliding bearing is provided to increase space efficiency.

JP 2012-132571 A

  In some cases, a support member for positioning the slide bearing in the axial direction is provided, and both ends of the slide bearing in the axial direction are fixed by the support member. In this case, since the axial length of the support member is required, the axial dimension of the pulley unit tends to be large. On the other hand, since the area where the pulley unit is installed is limited, it is desirable that the pulley unit has a smaller axial dimension. Further, in order to easily assemble the slide bearing, a split-type slide bearing divided in the circumferential direction may be employed. In this case, lubricant such as internal grease may leak from the slit portion of the slide bearing.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a pulley unit that can reduce the length in the axial direction and suppress leakage of the lubricant.

  In order to achieve the above object, a pulley unit according to an aspect of the present invention includes a hub that rotates about a rotation shaft, a pulley that is supported by the hub via a slide bearing, and the hub. A first cam plate that rotates, a second cam plate that rotates integrally with the pulley and that can move in a direction along the rotation axis, a rolling element that contacts the first cam plate and the second cam plate, and the rotation An elastic member that deforms along with the movement of the second cam plate in the direction along the axis; and a support member that is provided on the opposite side of the second cam plate with respect to the elastic member in the direction along the rotation axis. The slide bearing has an annular shape continuous over the entire circumference, is provided on the outer peripheral surface of the support member, and is provided at one end of the slide bearing in a direction along the rotation axis. The provided support member and the slip Sandwiched between the member different from said supporting member provided on the other end side of the receiving.

  Thereby, the position of an axial direction is fixed because a slide bearing is pinched | interposed by the member from which the one end side and other end side of an axial direction differ. For this reason, the structure of a support member can be simplified and the length of an axial direction can be made small. Further, the slide bearing has an annular shape that is continuous over the entire circumference, and can prevent the internal lubricant from leaking to the outside. Therefore, the pulley unit can reduce the length in the axial direction and suppress leakage of the internal lubricant.

  As a desirable mode of the pulley unit, the support member includes an annular portion, a projecting portion, and a flange portion, and the annular portion is provided in a direction intersecting the rotation axis, and is provided on the rotation shaft of the elastic member. The projecting portion is provided on the outer side of the annular portion in the radial direction, and protrudes in the direction along the rotation axis, and the flange portion extends from the end of the projecting portion in the radial direction. It protrudes to the outside and is preferably in contact with one end of the plain bearing. Thereby, the annular portion receives the axial force of the elastic member and can position the elastic member. Moreover, since the flange part is provided, the position of the one end side of a slide bearing is fixed by the flange part. Since it is not necessary to provide the support member with a configuration for contacting the other end side of the slide bearing, the configuration of the support member can be simplified and the axial length can be reduced.

  As a desirable mode of the pulley unit, the member different from the support member is the pulley, and a step portion is provided on an inner peripheral surface of the pulley, and the other end side of the slide bearing is in contact with the step portion. It is preferable. Thereby, the pulley also serves as a member for contacting the other end of the slide bearing. For this reason, since it is not necessary to add another member to the other end side of the slide bearing, the axial length can be reduced.

  As a desirable mode of the pulley unit, a member different from the support member is a spacer, and the spacer is provided between the elastic member and the support member, and the spacer is formed from the outer peripheral surface of the support member. However, it is preferable that the other end side of the sliding bearing is in contact with the extending portion, including an extending portion extending outward in the radial direction. Thereby, the position of the slide bearing in the axial direction is determined by the support member and the extended portion of the spacer. Since the spacer is provided, the distance between the elastic member and the support member can be adjusted to a desired size, and appropriate torsional characteristics can be obtained.

  As a desirable mode of the pulley unit, the surface hardness of the spacer is preferably larger than the surface hardness of the support member. Thereby, abrasion of the spacer that contacts the elastic member can be suppressed. Moreover, the heat treatment process for improving the surface hardness is performed only on the spacer, and the process for improving the surface hardness of the support member can be omitted. For this reason, manufacturing cost can be reduced.

  According to the present invention, the length in the axial direction can be reduced and leakage of the lubricant can be suppressed.

FIG. 1 is a front view of an engine to which a pulley unit according to the first embodiment is applied. FIG. 2 is a perspective view of the pulley unit according to the first embodiment. FIG. 3 is a side view of the pulley unit according to the first embodiment. FIG. 4 is a front view of the pulley unit according to the first embodiment. 5 is a cross-sectional view taken along line AA in FIG. FIG. 6 is an exploded perspective view of the pulley unit according to the first embodiment. FIG. 7 is an enlarged cross-sectional view of the periphery of the plain bearing in FIG. FIG. 8 is a perspective view of the plain bearing according to the first embodiment. FIG. 9 is a perspective view of the hub according to the first embodiment. FIG. 10 is a perspective view of the second cam plate according to the first embodiment. FIG. 11 is a side view showing the pulley unit according to the first embodiment, excluding the pulley. FIG. 12 is an enlarged side view of the periphery of the rolling element unit in FIG. FIG. 13 is a schematic diagram showing the movement of the rolling element unit and the second cam plate when torque is transmitted from the engine to the pulley. FIG. 14 is a schematic diagram showing the movement of the rolling element unit and the second cam plate when torque is transmitted from the generator to the hub. 15 is a cross-sectional view taken along the line BB in FIG. FIG. 16 is a graph showing the relationship between the torque applied to the pulley or the hub and the relative angle between the pulley and the hub. FIG. 17 is a cross-sectional view for explaining the axial gap between the support member and the elastic member. FIG. 18 is a graph showing the relationship between torque and relative angle when no gap is provided. FIG. 19 is a graph showing the relationship between torque and relative angle when no gap is provided and preload is applied to the elastic member. FIG. 20 is a graph showing the relationship between torque and relative angle when a gap is provided. FIG. 21 is a cross-sectional view of a pulley unit according to the second embodiment. FIG. 22 is an enlarged cross-sectional view of the periphery of the plain bearing in FIG.

  Hereinafter, the present invention will be described in detail with reference to the drawings. The present invention is not limited by the following modes for carrying out the invention (hereinafter referred to as embodiments). In addition, constituent elements in the following embodiments include those that can be easily assumed by those skilled in the art, those that are substantially the same, and those in a so-called equivalent range. Furthermore, the constituent elements disclosed in the following embodiments can be appropriately combined.

(First embodiment)
FIG. 1 is a front view of an engine to which a pulley unit according to the first embodiment is applied. As shown in FIG. 1, for example, a generator 103, a water pump 105, a compressor 106, and the like are mounted on the vehicle as auxiliary machines for the engine 10. For example, the generator 103 according to the first embodiment can generate power for supplying power to the engine 10 in addition to generating power using the power generated by the engine 10. That is, the generator 103 is an ISG (Integrated Starter Generator). The water pump 105 is a pump for circulating the cooling water of the engine 10. The compressor 106 is a device for compressing a refrigerant used in a car air conditioner.

  Generator 103, water pump 105 and compressor 106 are driven by the power of engine 10. The power of the engine 10 is transmitted to the generator 103, the water pump 105, and the compressor 106 via the belt 109 shown in FIG. The belt 109 is, for example, a V-ribbed belt. The belt 109 is attached to the crankshaft pulley 11, idler pulley 12, pulley unit 13, tensioner pulley 14, water pump pulley 15, and compressor pulley 16.

  The crankshaft pulley 11 is connected to the crankshaft 101 of the engine 10. The idler pulley 12 is a device for adjusting the position of the belt 109. The pulley unit 13 is connected to the shaft of the generator 103. The tensioner pulley 14 is connected to the shaft of the tensioner 104. The tensioner 104 is a device for adjusting the tension of the belt 109. The water pump pulley 15 is connected to the shaft of the water pump 105. The compressor pulley 16 is connected to the shaft of the compressor 106.

  Since the generator 103 is an ISG, the power of the engine 10 may be transmitted to the generator 103, and conversely, the power of the generator 103 may be transmitted to the engine 10. That is, the pulley unit 13 needs to be able to transmit the torque transmitted to the belt 109 to the shaft of the generator 103 and to transmit the torque generated by the generator 103 to the belt 109.

  Further, since the crankshaft 101 rotates due to the explosion in the engine 10, the rotation speed of the crankshaft 101 varies. On the other hand, the inertia of the shaft of the generator 103 is relatively large. For this reason, the tension of the belt 109 may fluctuate. When the fluctuation of the tension of the belt 109 is large, the initial tension of the belt 109 is increased in order to suppress the slip of the belt 109. However, an increase in the initial tension of the belt 109 leads to an increase in friction and damage to the belt 109. For this reason, it is desirable that the pulley unit 13 can suppress fluctuations in the tension of the belt 109.

  FIG. 2 is a perspective view of the pulley unit according to the first embodiment. FIG. 3 is a side view of the pulley unit according to the first embodiment. FIG. 4 is a front view of the pulley unit according to the first embodiment. 5 is a cross-sectional view taken along line AA in FIG. FIG. 6 is an exploded perspective view of the pulley unit according to the first embodiment. FIG. 7 is an enlarged cross-sectional view of the periphery of the plain bearing in FIG. FIG. 8 is a perspective view of the plain bearing according to the first embodiment. FIG. 9 is a perspective view of the hub according to the first embodiment. FIG. 10 is a perspective view of the second cam plate according to the first embodiment. FIG. 11 is a side view showing the pulley unit according to the first embodiment, excluding the pulley. FIG. 12 is an enlarged side view of the periphery of the rolling element unit in FIG.

  As shown in FIGS. 5 and 6, the pulley unit 13 includes a pulley 2, a hub 3, a bearing 4, a rolling element unit 5, a second cam plate 6, a bearing 71, a bearing ring 72, an elastic member. A member 73, a guide member 74, a plain bearing 75, a retaining ring 76, and a seal 77 are provided.

  The pulley 2 is a member in contact with the belt 109 shown in FIG. As shown in FIG. 5, the pulley 2 is supported by the hub 3 via bearings 4 and slide bearings 75 provided at both ends of the hub 3, and can rotate around the rotation axis Z. As shown in FIG. 3, the pulley 2 is a substantially cylindrical member, and includes a belt attachment portion 21 and an elastic member storage portion 22. The inner diameter of the elastic member storage portion 22 is larger than the inner diameter of the belt attachment portion 21.

  As shown in FIG. 5, the belt attachment portion 21 has a plurality of grooves 211 on the outer peripheral surface. The belt 109 is fitted in the groove 211. Power is transmitted between the belt 109 and the pulley 2 due to friction generated between the belt 109 and the groove 211. Moreover, the belt attaching part 21 has a plurality of first teeth 2a on the inner peripheral surface. The plurality of first teeth 2a are arranged at equal intervals in the circumferential direction around the rotation axis Z. The plurality of first teeth 2a are, for example, involute splines. The first teeth 2a are along the rotation axis Z. That is, the longitudinal direction of the first tooth 2 a is parallel to the rotation axis Z.

  In the following description, the direction along the rotation axis Z is described as the axial direction. The radial direction around the rotation axis Z is simply referred to as the radial direction. The circumferential direction around the rotation axis Z is simply referred to as the circumferential direction.

  The hub 3 is a member connected to the shaft of the generator 103 shown in FIG. The shaft of the generator 103 is inserted inside the cylindrical hub 3. The hub 3 rotates integrally with the shaft of the generator 103 around the rotation axis Z. As shown in FIG. 5, the hub 3 includes a bearing mounting portion 31, a base portion 32, and a first cam plate 33. The bearing mounting portion 31 is cylindrical and contacts the bearing 4. A distance D31 from the rotating shaft Z to the outer peripheral surface of the bearing mounting portion 31 (a distance half the outer diameter of the bearing mounting portion 31) is larger than a distance D52 from the rotating shaft Z to the rolling element 52 as shown in FIG. The base portion 32 has a cylindrical shape having an outer diameter smaller than the outer diameter of the bearing mounting portion 31. The first cam plate 33 is disposed between the bearing mounting portion 31 and the base portion 32 and has a substantially annular shape. The first cam plate 33 is formed integrally with the bearing mounting portion 31 and the base portion 32, for example.

  As shown in FIG. 9, the first cam plate 33 includes a bearing contact surface 330, a first cam surface 331, a flat surface 332, and a second stopper 33s. The bearing contact surface 330 is in contact with the bearing 4 and positions the bearing 4. The first cam surface 331 and the flat surface 332 are surfaces opposite to the bearing contact surface 330. The first cam surface 331 includes an inclined surface 331a, a bottom surface 331b, and an inclined surface 331c. The bottom surface 331b is disposed between the slope 331a and the slope 331c. The bottom surface 331 b has a shape along the rolling element 52. The inclined surface 331a and the inclined surface 331c form an angle with respect to an orthogonal plane with respect to the rotation axis Z. More specifically, as shown in FIG. 12, the angle θ1 formed by the inclined surface 331a and the plane orthogonal to the rotation axis Z and the angle θ2 formed by the inclined surface 331c and the plane orthogonal to the rotation axis Z are equal and constant. The flat surface 332 is parallel to a plane orthogonal to the rotation axis Z. As shown in FIG. 9, three first cam surfaces 331 are arranged at equal intervals in the circumferential direction, and a flat surface 332 is arranged between the two first cam surfaces 331. That is, the first cam surface 331 and the flat surface 332 are alternately arranged in the circumferential direction.

  The bearing 4 shown in FIGS. 5 and 6 is a radial bearing, for example, a deep groove ball bearing. The bearing 4 is press-fitted into the bearing mounting portion 31, for example. The inner ring of the bearing 4 is in contact with the outer peripheral surface of the bearing mounting portion 31, and the outer ring of the bearing 4 is in contact with the inner peripheral surface of the belt mounting portion 21. The bearing 4 supports the pulley 2 so that it can rotate around the rotation axis Z.

  As shown in FIGS. 5 and 6, the rolling element unit 5 includes a cage 51 and a plurality of rolling elements 52. The cage 51 is a member for positioning the plurality of rolling elements 52. The cage 51 is annular and has a plurality of pockets for accommodating the rolling elements 52. For example, three pockets are arranged at equal intervals in the circumferential direction. Further, the cage 51 can rotate around the rotation axis Z independently of the hub 3. The rolling element 52 is, for example, a roller. The number of rolling elements 52 is three, for example. Each rolling element 52 is fitted in the pocket of the cage 51. The rolling element 52 can rotate (spin) within the pocket of the cage 51 and can rotate (revolve) around the rotation axis Z together with the cage 51. The rolling element 52 contacts the first cam surface 331 (see FIG. 9) and a second cam surface 61 described later.

  The second cam plate 6 is a member that rotates integrally with the pulley 2, and is disposed next to the rolling element unit 5. As shown in FIG. 10, the second cam plate 6 includes a bearing contact surface 60, a second cam surface 61, a flat surface 62, and a plurality of second teeth 6a. The bearing contact surface 60 is in contact with the bearing 71 (see FIGS. 5 and 6). The second cam surface 61 includes an inclined surface 61a, a bottom surface 61b, and an inclined surface 61c. The bottom surface 61b is disposed between the slope 61a and the slope 61c. The bottom surface 61 b has a shape along the rolling element 52. The inclined surface 61a and the inclined surface 61c form an angle with respect to an orthogonal plane with respect to the rotation axis Z. More specifically, as shown in FIG. 12, the angle θ3 formed by the inclined surface 61a and the plane orthogonal to the rotation axis Z and the angle θ4 formed by the inclined surface 61c and the plane orthogonal to the rotation axis Z are equal to each other and constant. For example, the angle θ3 and the angle θ4 are equal to the angle θ1 and the angle θ2. The flat surface 62 is parallel to a plane orthogonal to the rotation axis Z. As shown in FIG. 10, three second cam surfaces 61 are arranged at equal intervals in the circumferential direction, and a flat surface 62 is arranged between the two second cam surfaces 61. That is, the second cam surfaces 61 and the flat surfaces 62 are alternately arranged in the circumferential direction.

  The second teeth 6 a are provided on the outer peripheral surface of the second cam plate 6. As shown in FIG. 10, the plurality of second teeth 6a are arranged at equal intervals in the circumferential direction. The plurality of second teeth 6a are, for example, involute splines. The second teeth 6a are along the rotation axis Z. That is, the longitudinal direction of the second tooth 6 a is parallel to the rotation axis Z. The second teeth 6a mesh with the first teeth 2a (see FIG. 5) of the pulley 2. Thereby, the second cam plate 6 rotates integrally with the pulley 2. The second cam plate 6 can move in the axial direction.

  A bearing 71 shown in FIG. 5 is a thrust bearing, for example, a thrust needle bearing. The bearing 71 is disposed next to the second cam plate 6. The bearing 71 is in contact with the bearing contact surface 60 of the second cam plate 6. The bearing 71 supports the second cam plate 6 so as to be rotatable about the rotation axis Z. The bearing 71 moves together with the second cam plate 6 when the second cam plate 6 moves in the axial direction.

  The race ring 72 is an annular member and is in contact with the bearing 71. A bearing 71 is sandwiched between the second cam plate 6 and the raceway ring 72. The track ring 72 is also called a race or washer. The race ring 72 moves together with the second cam plate 6 and the bearing 71 when the second cam plate 6 and the bearing 71 move in the axial direction. The race ring 72 transmits the axial load received from the bearing 71 to the elastic member 73. In addition, as shown in FIG. 5, the rolling element unit 5, the second cam plate 6, the bearing 71, and the race ring 72 are opposed to the inner peripheral surface of the belt mounting portion 21.

  The elastic member 73 is a plurality of disc springs stacked in the axial direction as shown in FIG. 5, for example. One end of the elastic member 73 in the axial direction is in contact with the race ring 72 and the other end is in contact with the guide member 74. For example, the maximum deformation amount (deflection amount) of the elastic member 73 is smaller than the diameter of the rolling element 52. For this reason, it can suppress that the rolling element 52 deviates from the 1st cam surface 331 (refer FIG. 9) and the 2nd cam surface 61 (refer FIG. 10). The elastic member 73 is stored in the elastic member storage portion 22 of the pulley 2. That is, the elastic member 73 faces the first inner peripheral surface 22 a of the elastic member storage portion 22.

  The guide member 74 is a support member for supporting the sliding bearing 75 and positioning the elastic member 73. The guide member 74 has an annular shape and is fitted into the base portion 32 of the hub 3. The guide member 74 is provided on the opposite side of the second cam plate with respect to the elastic member 73 in the axial direction, and is disposed adjacent to the elastic member 73 in the axial direction.

  Specifically, as shown in FIGS. 5 and 7, the guide member 74 includes an annular portion 74a, a protruding portion 74b, and a flange portion 74c. The annular portion 74 a is provided in a direction intersecting with the rotation axis Z and is parallel to a plane orthogonal to the rotation axis Z. The inner end of the annular portion 74 a in the radial direction is fixed by a retaining ring 76 provided on the base portion 32. The annular portion 74a is disposed between the retaining ring 76 and the elastic member 73 in the axial direction, whereby the position of the elastic member 73 in the axial direction is determined.

  The protruding portion 74b is provided outside the annular portion 74a in the radial direction and protrudes in the axial direction. The protruding portion 74b protrudes in a direction away from the elastic member 73 with respect to the annular portion 74a. The flange portion 74c protrudes outward in the radial direction from the end portion of the protrusion 74b.

  A slide bearing 75 is disposed on the outer peripheral surface 74d of the protrusion 74b. The slide bearing 75 is a radial bearing, and may be a slide bearing such as an oil-impregnated bearing in which a porous material is impregnated with oil. As shown in FIG. 8, the plain bearing 75 has an annular shape that is continuous over the entire circumference. In other words, the sliding bearing 75 is not a cracked type, and is not provided with slits, notches or the like for dividing in the circumferential direction. As shown in FIGS. 5 and 7, the slide bearing 75 is provided between the outer peripheral surface 74 d of the protrusion 74 b of the guide member 74 and the second inner peripheral surface 22 b of the elastic member storage portion 22. With such a configuration, the plain bearing 75 supports the pulley 2 together with the bearing 4.

  As shown in FIGS. 5 and 7, the slide bearing 75 includes a guide member 74 provided on one end side of the slide bearing 75 and a guide member 74 provided on the other end side of the slide bearing 75 in the axial direction. It is sandwiched between different members. Specifically, one end side of the sliding bearing 75 in the axial direction is in contact with the flange portion 74c. Further, as described above, the elastic member storage portion 22 has the first inner peripheral surface 22a and the second inner peripheral surface 22b. The first inner peripheral surface 22 a faces the elastic member 73. The second inner peripheral surface 22 b faces the guide member 74 and the slide bearing 75. The inner diameter of the second inner peripheral surface 22b is larger than the inner diameter of the first inner peripheral surface 22a. Thereby, the step part 22c is formed by the 1st internal peripheral surface 22a and the 2nd internal peripheral surface 22b. The other end side of the slide bearing 75 in the axial direction is in contact with the step portion 22c. Thereby, the axial position of the slide bearing 75 is fixed.

  Thus, in the present embodiment, the slide bearing 75 is sandwiched in the axial direction by the guide member 74 and the pulley 2, so that the axial position is fixed. For this reason, it is not necessary to provide the guide member 74 with a configuration for contacting the other end side of the slide bearing 75 in the axial direction, and the configuration of the guide member 74 can be simplified. Therefore, the axial length of the guide member 74 can be reduced as compared with the configuration in which the axial position of the sliding bearing 75 is fixed only by the guide member 74. As a result, the length of the pulley unit 13 in the axial direction can be reduced. Further, the flange portion 74c of the guide member 74 is provided only at one end portion in the axial direction of the protruding portion 74b, and is not provided at the other end portion. For this reason, the slide bearing 75 can be easily assembled to the guide member 74 even if the slide bearing 75 has an annular shape continuous over the entire circumference.

  A lubricant is provided between the pulley 2 and the hub 3. The lubricant is, for example, grease. For example, in the space S (see FIG. 5) between the pulley 2 and the hub 3, the lubricant fills at least a region outside the radially inner end of the rolling element 52. That is, as shown in FIG. 5, in a cross section including the rotation axis Z, a straight line that passes through the inner end portion in the radial direction of the rolling element 52 and is parallel to the rotation axis Z is defined as a straight line L1. A region outside the straight line L1 is filled with a lubricant. For this reason, since the periphery of the slide bearing 75 is also filled with the lubricant, the slide bearing 75 can support the pulley 2 so as to be able to rotate around the rotation axis Z.

  As shown in FIG. 8, the plain bearing 75 has an annular shape that is continuous over the entire circumference. For this reason, since a slit, a notch, etc. are not provided compared with the case where a crack type bearing is used as the sliding bearing 75, it is possible to prevent the lubricant from leaking to the outside. Furthermore, since the slide bearing 75 is not provided with a slit, a notch or the like, the load capacity of the radial load can be increased.

  The retaining ring 76 is a member for positioning the guide member 74. The retaining ring 76 is a substantially annular shape having one slit, and is fitted into a groove 39 provided at the end of the base 32 as shown in FIG. Thereby, the movement of the guide member 74 in the axial direction is restricted. Therefore, the end portion of the elastic member 73 in contact with the guide member 74 cannot move in the axial direction. When the second cam plate 6, the bearing 71, and the race ring 72 move toward the elastic member 73, one end of the elastic member 73 moves in the axial direction, while the other end of the elastic member 73 does not move. For this reason, the elastic member 73 is deformed. At this time, since an elastic force is generated in the elastic member 73, the second cam plate 6 receives a reaction force from the elastic member 73 via the raceway ring 72 and the bearing 71.

  The seal 77 is a member for closing the opening at the end of the pulley 2. As shown in FIG. 6, the seal 77 is a substantially disk-shaped member, and is fitted into a groove 29 provided at the end of the pulley 2. The seal 77 prevents the lubricant from leaking and prevents foreign matter from entering the inside of the pulley 2.

  When no torque is applied to either the pulley 2 or the hub 3, the rolling elements 52 are in contact with the bottom surface 331b and the bottom surface 61b as shown in FIG. When the rolling element 52 is in contact with the bottom surface 331b and the bottom surface 61b, the distance between the flat surface 332 and the flat surface 62 is the smallest. At this time, the elastic member 73 is not deformed.

  When torque is applied to the pulley 2 or the hub 3, the relative angle between the pulley 2 and the hub 3 (hereinafter simply referred to as a relative angle) changes. The relative angle is the deviation of the rotation angle between the pulley 2 and the hub 3 with reference to the case where the distance between the flat surface 332 and the flat surface 62 is the smallest (in the state shown in FIG. 12). It is. That is, the relative angle is 0 ° when the distance between the flat surface 332 and the flat surface 62 is the smallest.

  FIG. 13 is a schematic diagram showing the movement of the rolling element unit and the second cam plate when torque is transmitted from the engine to the pulley. FIG. 14 is a schematic diagram showing the movement of the rolling element unit and the second cam plate when torque is transmitted from the generator to the hub. That is, FIG. 13 shows the movement of the rolling element unit 5 and the second cam plate 6 when the pulley 2 is on the driving side (the hub 3 is the driven side). FIG. 14 shows the movement of the rolling element unit 5 and the second cam plate 6 when the pulley 2 is on the driven side (the hub 3 is on the driving side).

  As shown in FIG. 13, when the torque T1 is applied to the pulley 2, the rolling elements 52 rotate and revolve, and ascend the slope 61c. When the rolling element 52 rises on the inclined surface 61 c, it is sandwiched between the inclined surface 61 c and the inclined surface 331 a, so that it receives an axial reaction force from the first cam plate 33. Thereby, the rolling element unit 5 and the 2nd cam board 6 move to the direction away from the 1st cam board 33, and the elastic member 73 (refer FIG. 5) deform | transforms. A part of the torque T1 is consumed by the deformation of the elastic member 73, while the remaining part of the torque T1 rotates the hub 3 gradually. When the reaction force received by the rolling element 52 from the first cam plate 33 becomes equal to the elastic force generated by the elastic member 73, the rolling element unit 5 and the second cam plate 6 are stopped. As a result, torque T1 is transmitted from the pulley 2 to the hub 3. That is, the hub 3 rotates integrally with the pulley 2. Thus, the pulley unit 13 can transmit the torque transmitted to the belt 109 to the shaft of the generator 103. Further, as described above, the maximum deformation amount of the elastic member 73 is smaller than the diameter of the rolling element 52. For this reason, even if the elastic member 73 is deformed to the maximum, the contact between the rolling element 52 and the first cam plate 33 and the contact between the rolling element 52 and the second cam plate 6 are maintained.

  Even if the torque T1 changes suddenly, a part of the torque T1 is consumed by the deformation of the elastic member 73, so that the change in the torque transmitted to the hub 3 is more gradual than the change in the torque T1. For this reason, the relative rotational speed of the hub 3 with respect to the rotational speed of the pulley 2 hardly changes. Therefore, the pulley unit 13 can suppress fluctuations in the tension of the belt 109.

  As shown in FIG. 14, when the torque T2 is applied to the hub 3, the rolling elements 52 rotate and revolve, and ascend the slope 331c. When the rolling element 52 rises on the inclined surface 331c, it is sandwiched between the inclined surface 331c and the inclined surface 61a, so that it receives an axial reaction force from the first cam plate 33. Thereby, the rolling element unit 5 and the 2nd cam board 6 move to the direction away from the 1st cam board 33, and the elastic member 73 (refer FIG. 5) deform | transforms. A part of the torque T2 is consumed by the deformation of the elastic member 73, while the remaining part of the torque T2 gradually rotates the second cam plate 6 and the pulley 2. When the reaction force received by the rolling element 52 from the first cam plate 33 becomes equal to the elastic force generated by the elastic member 73, the rolling element unit 5 and the second cam plate 6 are stopped. As a result, torque T2 is transmitted from the hub 3 to the pulley 2. That is, the pulley 2 rotates integrally with the hub 3. Thus, the pulley unit 13 can transmit the torque generated by the generator 103 to the belt 109.

  Even if the torque T2 changes suddenly, a part of the torque T2 is consumed by the deformation of the elastic member 73, so that the change in the torque transmitted to the pulley 2 becomes more gradual than the change in the torque T2. For this reason, the relative rotational speed of the pulley 2 with respect to the rotational speed of the hub 3 hardly changes. Therefore, the pulley unit 13 can suppress fluctuations in the tension of the belt 109.

  By the way, when the rolling element 52 rides on the flat surface 332 of the first cam plate 33 and the flat surface 62 of the second cam plate 6, excessive stress is generated in the rolling element 52. For this reason, the rolling element 52 may be damaged. On the other hand, in the pulley unit 13, the pulley 2 includes a first stopper 2s, and the hub 3 includes a second stopper 33s.

  15 is a cross-sectional view taken along the line BB in FIG. FIG. 16 is a graph showing the relationship between the torque applied to the pulley or the hub and the relative angle between the pulley and the hub.

  As shown in FIG. 15, the first cam plate 33 of the hub 3 includes a second stopper 33 s that is a protrusion on the outer peripheral surface. For example, the number of second stoppers 33s is three. Three second stoppers 33s are arranged at equal intervals in the circumferential direction. That is, in the cross section shown in FIG. 15, the angle α1 formed by the straight line passing through the rotation axis Z and the vertex of one second stopper 33s and the straight line passing through the rotation axis Z and the vertex of the other second stopper 33s is 120 °. is there. The second stopper 33s is provided on the outer peripheral surface of the first cam plate 33 adjacent to the flat surface 332, for example. Specifically, the circumferential position of the second stopper 33 s is equal to the circumferential intermediate position of the flat surface 332. The radial height H1 of the second stopper 33s is greater than half the height H3 of the gap between the first cam plate 33 and the belt mounting portion 21. The height H3 of the gap is equal to the difference between the inner diameter of the belt mounting portion 21 and the outer diameter of the first cam plate 33.

  The belt mounting portion 21 of the pulley 2 includes a first stopper 2s that is a protrusion on the inner peripheral surface. For example, the number of first stoppers 2s is six. Two first stoppers 2s constitute one first stopper group 2sg. The distance between adjacent first stoppers 2s in one first stopper group 2sg is smaller than the distance between adjacent first stopper groups 2sg. Three first stopper groups 2sg are arranged at equal intervals in the circumferential direction. That is, in the cross section shown in FIG. 15, an angle α2 formed by a straight line passing through the intermediate point between the rotation axis Z and one first stopper group 2sg and a straight line passing through the intermediate point between the rotation axis Z and the other first stopper group 2sg. Is 120 °. Also, the radial height H2 of the first stopper 2s is equal to the height H1 of the second stopper 33s. When viewed from the axial direction, the shape of the first stopper 2s is the same as the shape of the first teeth 2a (see FIG. 5). The position of the first stopper 2s in the circumferential direction is the same as the position of the first teeth 2a in the circumferential direction. The first stopper 2s is manufactured together with the first teeth 2a in the manufacturing process of the first teeth 2a. For example, the first teeth 2a and the first stopper 2s are manufactured by broaching.

  When torque is not applied to either the pulley 2 or the hub 3 (in the state shown in FIG. 12), the second stopper 33s is positioned between the two first stopper groups 2sg as shown in FIG. When torque is applied to the pulley 2 or the hub 3, the relative angle changes, so the second stopper 33s approaches the first stopper 2s. When the angle α3 shown in FIG. 15 becomes 0 °, the second stopper 33s comes into contact with the first stopper 2s. The angle α3 is an angle formed by a straight line passing through the rotation axis Z and the point P1 on the side surface of the second stopper 33s and a straight line passing through the rotation axis Z and the point P2 on the side surface of the first stopper 2s. The points P1 and P2 are located on the same circumference around the rotation axis Z. Further, as shown in FIG. 15, an angle formed by a straight line passing through one end in the circumferential direction of the rotation axis Z and the first cam surface 331 and a straight line passing through the other end in the circumferential direction of the rotation axis Z and the first cam surface 331. Is an angle β. The angle α3 when the relative angle is 0 ° is smaller than the angle β. The angle β is 60 °.

  If the relative angle is equal to or larger than the angle β, the rolling element 52 rides on the flat surface 332 and the flat surface 62. However, in the pulley unit 13 according to the first embodiment, since the angle α3 when the relative angle is 0 ° is smaller than the angle β, the maximum value of the relative angle is smaller than the angle β as shown in FIG. . For this reason, even if excessive torque is generated in the pulley 2 or the hub 3, the relative angle does not exceed the angle β, so that the rolling element 52 does not ride on the flat surface 332 and the flat surface 62. Therefore, the rolling element 52 does not contact the flat surface 332 and the flat surface 62. For this reason, since the hardness calculated | required by the flat surface 332 and the flat surface 62 becomes low, the area which needs processing, such as induction hardening, for example becomes small. As a result, the manufacturing cost of the pulley unit 13 is reduced.

  Further, since the three second stoppers 33s are arranged at equal intervals and the three first stopper groups 2sg are arranged at equal intervals, the three second stoppers 33s are in contact with the first stopper 2s at the same time. For this reason, compared with the case where the number of the 2nd stoppers 33s which contact | connects the 1st stopper 2s is one, the force added to one 1st stopper 2s and the force added to one 2nd stopper 33s reduce. For this reason, the first stopper 2s and the second stopper 33s are not easily damaged.

  If the number of first stoppers 2s included in the first stopper group 2sg is one, one first stopper 2s receives a force in two directions. In contrast, in the first embodiment, since the first stopper group 2sg includes two first stoppers 2s, the direction of the force applied to one first stopper 2s is constant. That is, one of the two first stoppers 2 s included in the first stopper group 2 sg is in contact with the second stopper 33 s when the hub 3 rotates forward with respect to the pulley 2, and the other is the hub 3 with respect to the pulley 2. The second stopper 33s is in contact with the second stopper 33s. For this reason, compared with the case where one 1st stopper 2s receives the force of 2 directions, the 1st stopper 2s becomes difficult to be damaged.

  Next, the relationship between the space between the elastic member 73 and the guide member 74 and the torsional characteristics (torque transmission characteristics) of the pulley unit 13 will be described. FIG. 17 is a cross-sectional view for explaining the axial gap between the support member and the elastic member. FIG. 18 is a graph showing the relationship between torque and relative angle when no gap is provided. FIG. 19 is a graph showing the relationship between torque and relative angle when no gap is provided and preload is applied to the elastic member. FIG. 20 is a graph showing the relationship between torque and relative angle when a gap is provided. 18 to 20 show the torsional characteristics in the range where the relative angle is smaller than the angle β as compared with the graph shown in FIG.

  5 and 7, the configuration in which the axial end portion of the elastic member 73 is in contact with the guide member 74 has been described. However, the configuration is not limited thereto. As shown in FIG. 17, the size of the gap between the axial end portion 73a of the elastic member 73 and the annular portion 74a of the guide member 74 is defined as a space W1.

  FIG. 18 shows torsional characteristics when no gap is provided, that is, when the interval W1 = 0 and no preload is applied to the elastic member 73. FIG. In this case, as shown in FIG. 18, the relative angle changes in proportion to the magnitude of the torque.

  FIG. 19 shows torsional characteristics when no gap is provided, that is, when the interval W1 = 0 and preload is applied to the elastic member. In this case, as shown in FIG. 19, the relative angle does not change until torques T3 and T4 having a predetermined magnitude are applied, and the relative angle changes when a torque larger than the absolute value of torques T3 and T4 is applied. To do.

  FIG. 20 shows torsional characteristics when a gap is provided. In this case, as shown in FIG. 20, the torsional characteristic is obtained in which the relative angle changes to predetermined angles θa and θb in a state where no torque is applied. Here, the state in which no torque is applied is a state in which no external torque is applied to the pulley 2 or the hub 3. In this case, for example, a friction torque derived from friction generated in a component such as the bearing 4 (see FIG. 5) is generated. The relative angle changes due to the friction torque. The angles θa and θb are smaller than the angle β shown in FIG. Further, the torques T3 and T4 shown in FIG. 19 are smaller than the magnitude of the torque corresponding to the angle β shown in FIG.

  As described above, the torsional characteristics change according to the size of the interval W1 and the preload applied to the elastic member 73. In other words, in order to obtain the desired torsional characteristics of the pulley unit 13, axial dimension management of the elastic member 73 and the guide member 74 is important.

  In the present embodiment, the pulley unit 13 does not necessarily have to be applied to the generator 103 that is an ISG, and may be applied to a generator that does not generate motive power to be supplied to the engine (only performs power generation). That is, the pulley unit 13 is not limited to the pulley unit 13 that can transmit bidirectional torque, and may be a pulley unit that can transmit only one-way torque. Specifically, the pulley unit 13 may be a device that can transmit the torque transmitted to the belt to the generator, and may not necessarily be a device that transmits the torque generated by the generator to the belt.

  In addition, the rolling element 52 does not necessarily need to be a roller. For example, the rolling element 52 may be a ball. The elastic member 73 is not necessarily a plurality of disc springs. For example, the elastic member 73 may be a coil spring.

  Note that the first cam plate 33 is not necessarily formed integrally with the bearing mounting portion 31 and the base portion 32. For example, the first cam plate 33 may be processed separately from the bearing mounting portion 31 and the base portion 32. In this case, the first cam plate 33 is fixed to the outer peripheral surface of the bearing mounting portion 31 or the outer peripheral surface of the base portion 32.

  Note that the angle θ1 and the angle θ2 shown in FIG. 12 may be different. The angle θ3 and the angle θ4 may be different. Further, the angle θ1, the angle θ2, the angle θ3, and the angle θ4 are not necessarily constant. For example, the angle θ <b> 1 and the angle θ <b> 2 may be increased toward the edge of the first cam surface 331. The angle θ <b> 3 and the angle θ <b> 4 may be increased toward the edge of the second cam surface 61.

  The number of first stoppers 2s included in the first stopper group 2sg may be three or more, or may be one. The hub 3 may have a plurality of second stopper groups including at least two second stoppers 33s. In this case, the plurality of second stopper groups are arranged at equal intervals in the circumferential direction. Further, the number of first stopper groups 2sg and the number of second stoppers 33s (number of second stopper groups) may not be three, but may be two or less, or four or more. Also good. However, the number of first stopper groups 2sg and the number of second stoppers 33s (number of second stopper groups) are preferably equal.

  As described above, the pulley unit 13 includes the hub 3, the pulley 2, the first cam plate 33, the second cam plate 6, the rolling element 52, the elastic member 73, and a guide member that is a support member. 74. The hub 3 rotates about the rotation axis Z. The pulley 2 is supported by the hub 3 via a slide bearing 75. The first cam plate 33 rotates integrally with the hub 3. The second cam plate 6 rotates integrally with the pulley 2 and can move in a direction along the rotation axis Z. The rolling elements 52 are in contact with the first cam plate 33 and the second cam plate 6. The elastic member 73 is deformed as the second cam plate 6 moves in the direction along the rotation axis Z. The guide member 74 is provided on the opposite side of the second cam plate 6 with respect to the elastic member 73 in the direction along the rotation axis Z. The slide bearing 75 has an annular shape that is continuous over the entire circumference. The slide bearing 75 is provided on the outer peripheral surface 74d of the guide member 74, and in the direction along the rotation axis Z, the guide member 74 provided on one end side of the slide bearing 75 and the other end side of the slide bearing 75. The guide member 74 is sandwiched between different members.

  Thereby, even if the torque applied to the pulley 2 or the hub 3 changes suddenly, a part of the torque is consumed by the deformation of the elastic member 73. For this reason, the relative rotational speed of the hub 3 with respect to the rotational speed of the pulley 2 hardly changes. As a result, the pulley unit 13 can suppress fluctuations in the tension of the belt 109. Further, the sliding bearing 75 is fixed in the axial position by being sandwiched between different members at one end and the other end in the axial direction. For this reason, the structure of the guide member 74 can be simplified and the axial length can be reduced. Further, the slide bearing 75 has an annular shape that is continuous over the entire circumference, and can prevent the internal lubricant from leaking to the outside. Therefore, the pulley unit 13 can reduce the length in the axial direction and suppress leakage of the internal lubricant.

  In the pulley unit 13, the guide member 74 includes an annular portion 74a, a protruding portion 74b, and a flange portion 74c. The annular portion 74 a is provided in a direction intersecting the rotation axis Z, and faces an end portion of the elastic member 73 in the direction along the rotation axis Z. The protrusion 74b is provided outside the annular portion 74a in the radial direction, and protrudes in the direction along the rotation axis Z. The flange portion 74 c protrudes outward in the radial direction from the end portion of the protruding portion 74 b and contacts one end side of the slide bearing 75.

  Thereby, the annular portion 74a can receive the axial force of the elastic member 73 and can position the elastic member 73. Moreover, since the flange part 74c is provided, the position of the one end side of the slide bearing 75 is fixed by the flange part 74c. Since it is not necessary to provide the guide member 74 with a configuration for contacting the other end side of the slide bearing 75, the configuration of the guide member 74 can be simplified and the length in the axial direction can be reduced.

  In the pulley unit 13, a member different from the guide member 74 is the pulley 2, and a step portion 22 c is provided on the inner peripheral surface (the first inner peripheral surface 22 a and the second inner peripheral surface 22 b) of the pulley 2. The other end side of the slide bearing 75 is in contact with the stepped portion 22c.

  Thereby, the pulley 2 also serves as a member for contacting the other end side of the slide bearing 75. For this reason, since it is not necessary to add another member to the other end side of the slide bearing 75, the axial length can be reduced.

(Second Embodiment)
FIG. 21 is a cross-sectional view of a pulley unit according to the second embodiment. FIG. 22 is an enlarged cross-sectional view of the periphery of the plain bearing in FIG. In addition, the same code | symbol is attached | subjected to the same component as what was demonstrated in 1st Embodiment mentioned above, and the overlapping description is abbreviate | omitted.

  In the pulley unit 13A of the present embodiment, a spacer 78 is provided between the elastic member 73 and the guide member 74A. The spacer 78 has an annular shape and is also called a shim. One surface of the spacer 78 faces the elastic member 73, and the other surface is in contact with the guide member 74A. The spacer 78 is a member for adjusting the size of the gap in the axial direction between the elastic member 73 and the guide member 74A. By providing the spacer 78, the axial gap between the elastic member 73 and the spacer 78 can be adjusted to an appropriate size. As a result, the torsional characteristics (see FIGS. 18 to 20) of the pulley unit 13A can be set to desired characteristics.

  Also in the present embodiment, the guide member 74A includes an annular portion 74Aa, a projecting portion 74Ab, and a flange portion 74Ac. The slide bearing 75 is provided on the outer peripheral surface 74Ad of the protrusion 74Ab. One end side of the sliding bearing 75 in the axial direction is in contact with the flange portion 74Ac. As a result, the position of the sliding bearing 75 on the one end side in the axial direction is fixed.

  The spacer 78 includes an extending portion 78a that extends outward in the radial direction from the outer peripheral surface 74Ad of the guide member 74A. The other end side of the sliding bearing 75 in the axial direction is in contact with the extending portion 78a. In the present embodiment, the axial distance between the extending portion 78a and the flange portion 74Ac, that is, the axial length of the outer peripheral surface 74Ad is equal to the axial length of the slide bearing 75. The slide bearing 75 is sandwiched between the flange portion 74Ac and the extension portion 78a in the axial direction. Thereby, the axial position of the slide bearing 75 is fixed.

  Thus, the axial position of the slide bearing 75 is fixed by the guide member 74A and the spacer 78. For this reason, it is not necessary to provide the guide member 74 with a configuration for contacting the other end side of the slide bearing 75 in the axial direction, and the configuration of the guide member 74 can be simplified. Accordingly, the axial length of the guide member 74 can be reduced as compared with the configuration in which the axial position of the sliding bearing 75 is fixed only by the guide member 74A. As a result, the length of the pulley unit 13 in the axial direction can be reduced. Further, compared to the first embodiment, the stepped portion 22c (see FIGS. 5 and 7) is not provided on the inner peripheral surface 22d of the pulley 2. For this reason, the structure of the pulley 2 can be simplified.

  Further, in the present embodiment, the surface hardness of the spacer 78 is larger than the surface hardness of the guide member 74A. Thereby, the wear of the spacer 78 in contact with the elastic member 73 can be suppressed. Here, the surface hardness indicates a value measured for the surface of each member, and is a value measured by a method such as a Vickers hardness test or a Rockwell hardness test.

  Further, since the spacer 78 is provided between the elastic member 73 and the guide member 74A, the elastic member 73 contacts the spacer 78 and does not contact the guide member 74A. For this reason, the heat treatment process for improving the surface hardness is performed only on the spacer 78, and the process for improving the surface hardness of the guide member 74A can be omitted. For this reason, the manufacturing cost of the pulley unit 13A can be reduced.

2 Pulley 2 s First stopper 3 Hub 4 Bearing 5 Rolling element unit 6 Second cam plate 10 Engine 11 Crankshaft pulley 13, 13A Pulley unit 21 Belt mounting portion 22 Elastic member storage portion 22a First inner peripheral surface 22b Second inner periphery Surface 22c Stepped portion 22d Inner peripheral surface 31 Bearing mounting portion 32 Base 33 First cam plate 33s Second stopper 51 Retainer 52 Rolling body 60 Bearing contact surface 61 Second cam surface 62 Flat surface 71 Bearing 72 Track ring 73 Elastic member 74 , 74A Guide members 74a, 74Aa Annular portion 74b, 74Ab Protruding portion 74c, 74Ac Flange portions 74d, 74Ad Outer peripheral surface 75 Slide bearing 76 Retaining ring 77 Seal 78 Spacer 101 Crankshaft 103 Generator 109 Belt 330 Bearing contact surface 331 First cam surface 332 Flat surface Z Rotation axis

Claims (5)

A hub that rotates about a rotation axis;
A pulley supported by the hub via a sliding bearing;
A first cam plate that rotates integrally with the hub;
A second cam plate that rotates integrally with the pulley and is movable in a direction along the rotation axis;
Rolling elements in contact with the first cam plate and the second cam plate;
An elastic member that deforms along with the movement of the second cam plate in the direction along the rotation axis;
A support member provided on the opposite side of the second cam plate with respect to the elastic member in a direction along the rotation axis;
The slide bearing has an annular shape continuous over the entire circumference, is provided on the outer peripheral surface of the support member, and is provided on one end side of the slide bearing in a direction along the rotation shaft. A pulley unit sandwiched between a member and a member different from the support member provided on the other end side of the slide bearing. The support member includes an annular portion, a protruding portion, and a flange portion,
The annular portion is provided in a direction intersecting the rotation axis, and is opposed to an end portion of the elastic member in a direction along the rotation axis,
The protruding portion is provided outside the annular portion in the radial direction, and protrudes in a direction along the rotation axis.
2. The pulley unit according to claim 1, wherein the flange portion protrudes outward in the radial direction from an end portion of the protruding portion and is in contact with one end side of the sliding bearing. A member different from the support member is the pulley,
A step portion is provided on the inner peripheral surface of the pulley,
The pulley unit according to claim 1 or 2, wherein the other end side of the plain bearing is in contact with the stepped portion. A member different from the support member is a spacer,
The spacer is provided between the elastic member and the support member,
The spacer includes an extending portion that extends radially outward from the outer peripheral surface of the support member,
The pulley unit according to claim 1 or 2, wherein the other end side of the sliding bearing is in contact with the extending portion.   The pulley unit according to claim 4, wherein a surface hardness of the spacer is larger than a surface hardness of the support member.

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