JP2017160922A - Power transmission device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power transmission device, in which the generation of abnormal noise is prevented in an operation state for a torque limiter mechanism to block a torque transmission, and which is easy in an assembly with a small number of components.SOLUTION: A torque limiter mechanism 30 is interposed between a pulley 10 and a rotary shaft 21 of an auxiliary machine 20. The torque limiter mechanism is formed of: a drive disc 31 arranged to oppose to the outer side face of the pulley; and a torque transmission member 41 attached to the shaft end part of the rotary shaft. A plurality of elastic member insertion parts are angularly equally disposed at the drive disc, and projections 34 are interposed between the adjoining elastic member insertion parts. The torque transmission member is equipped with an elastic piece 44, and the elastic piece is equipped with an inclined piece 45 and a pressure-contact piece 46. The pressure contact piece is pressure-welded to the projection piece part of the drive disc, thereby to transmit the rotation from the pulley to the rotation shaft through the drive disc and the torque transmission member. At the time when the rotation load of the rotation axis increases, a slippage is established at the contact part between the pressure-contact piece part and the projection part, and the elastic piece is inserted by its own restoration elasticity into the elastic piece insertion portion thereby to block the rotation transmission.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a power transmission device that transmits power from an engine to an automobile accessory.

  In general, when driving an automotive accessory such as an air conditioner compressor, the rotation of the crankshaft of the engine is transmitted to the rotating shaft of the automotive accessory by a belt transmission. At this time, if the rotational load of the rotating shaft of the automobile accessory increases, slippage may occur at the contact portion between the pulley attached to the rotating shaft and the belt, and the belt may be damaged.

  In order to eliminate such inconvenience, Patent Document 1 proposes a power transmission device having a torque limiter mechanism. In the power transmission device described in Patent Document 1, a pulley for transmitting engine power via a belt, a hub attached to a rotating shaft of a compressor, and a torque limiter mechanism provided between the hub and the pulley. And have.

  The torque limiter mechanism connects an elastic member made of a spring steel plate to the side surface of a pulley, and a plurality of arc-shaped extending portions provided on the outer peripheral portion of the elastic member have protrusions provided on the outer periphery of the hub. A hemisphere provided at the tip of the extending portion of the elastic member by pressing the tip of the extending portion against the hub-side protruding portion by the protruding portion on the outer periphery of the pressing member connected to the hub Is engaged with an engaging hole provided in the pressing member, and the rotation of the pulley is transmitted from the engaging portion of the hemispherical protruding part and the engaging hole to the rotating shaft via the elastic member and the hub. .

  Further, when the load on the rotating shaft increases, the engagement between the hemispherical protrusion provided at the distal end of the extension and the engagement hole provided in the pressing member is caused by the rotational force applied to the extension of the elastic member. The end of the extended portion is released from the protruding portion on the elastic member side and the protruding portion on the hub side to block rotation transmission from the pulley to the hub.

JP 2007-40403 A

  By the way, in the power transmission device described in the above-mentioned Patent Document 1, when a large load acts on the rotating shaft and the torque limiter mechanism is activated and the rotation transmission from the pulley to the hub is interrupted, the elastic member is moved together with the pulley. Rotate. At this time, since the extended portion provided in the elastic member extends in the circumferential direction and is easily elastically deformed, the extended portion swings around, and abnormal noise is generated by contact with the protruding portion of the pressing member, which is inconvenient to the driver. May give a pleasant feeling.

  In addition, since the power transmission from the pulley to the rotating shaft requires a resilient member, a pressing member, and a hub, the structure has a large number of parts, so there is a disadvantage that the cost is high and the assembly is troublesome.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a power transmission device that is easy to assemble with a reduced number of parts, preventing the generation of noise in an operating state in which a torque limiter mechanism interrupts torque transmission.

  In order to solve the above problems, in the present invention, a pulley supported rotatably around a pulley support shaft provided coaxially with a rotation shaft of an automobile accessory, and the pulley and the rotation shaft Power transmission comprising a torque limiter mechanism that is provided between the pulley and transmits the rotation of the pulley to the rotating shaft and interrupts the rotation transmission from the pulley to the rotating shaft when the rotational load of the rotating shaft exceeds a set value. In the apparatus, the torque limiter mechanism is attached to the shaft end portion of the rotating shaft so as to rotate the driving disk, and is arranged to face the outer surface of the pulley so as to be integrally rotated with the pulley. A torque transmission member that transmits to the rotating shaft, and one of the drive disk and the torque transmission member is provided with a plurality of elastic pieces, and the other is provided with an elastic piece insertion portion through which each elastic piece can be inserted. A protruding piece portion is provided between the elastic piece insertion portions, the inclined piece portion is provided on the elastic piece, and a pressure contact piece portion is provided at a tip of the inclined piece portion, and the inclined piece portion is in the natural state in the pulley. And an inclination angle that makes no contact with the member having the protruding piece portion, the inclined piece portion is elastically deformed and inserted into the elastic piece insertion portion, and the pressure contact piece portion is elastically applied to the protruding piece portion. It is a contacted configuration.

  In the power transmission device configured as described above, when the pulley rotates while the pressure contact piece portion of the elastic piece is in elastic contact with the protruding piece portion, the rotation is transmitted to the rotation shaft via the drive disk and the torque transmission member, and the rotation is performed. The shaft rotates in the same direction as the pulley, and the automobile accessory operates.

  When the rotation load of the rotating shaft increases due to troubles, etc. in the operating state of automobile auxiliary equipment, slip occurs at the contact portion between the pressure contact piece and the projecting piece of the elastic piece and the relative rotation occurs, and the elastic piece and the elastic piece are inserted. If the position of the part matches, the elastic piece will come out of the elastic piece insertion part by its own restoring elasticity and return to the natural state, the connection between the drive disk and the torque transmission member will be released, and the rotation transmission from the pulley to the rotating shaft will be cut off The pulley and the drive disk rotate freely. The free rotation of the pulley prevents the belt on the pulley from becoming over-tensioned.

  Here, it is preferable to provide a rotation engagement portion that is disengaged when the rotational load of the rotation shaft exceeds a set value at the elastic contact portion between the pressure contact piece portion and the protrusion piece portion. Providing the rotation engaging portion can prevent the torque limiter mechanism from malfunctioning due to relative rotation of the drive disk and the torque transmitting member due to fluctuations in rotational torque applied to the pulley.

  As the rotation engaging portion, a member composed of an engaging protrusion formed on the protruding piece portion and a concave portion provided on the pressure contact piece portion can be adopted. At this time, the engagement protrusion may be any one of a truncated cone shape, a semicircular shape, and an arc shape. The recess has a shape corresponding to the engagement protrusion.

  Here, the torque transmission member is provided in a disk shape on the same surface as the drive disk, and a plurality of elastic pieces are provided as a set adjacent to each other in the circumferential direction. A torque limiter mechanism having a large torque limiter value can be obtained by inclining the parts in opposite directions and causing the pressure contact piece part to be elastic contact that sandwiches the projecting piece part from both sides.

  Further, when connecting the pulley and the drive disk, a plurality of connection pins protrude from the outer periphery of the drive disk, and the pulley is provided with a pin hole into which each of the connection pins is inserted, and the pin hole and the connection pin are opposed to each other. A connection structure in which an elastic member is interposed between the parts is preferable.

  When the connecting structure having the above configuration is adopted, when the rotational torque applied to the pulley fluctuates, the elastic member is elastically deformed to absorb the torque fluctuation, and the effect of preventing damage to the connecting portion can be obtained.

  In the present invention, as described above, since the torque limiter mechanism is configured by the drive disk connected to the pulley and the torque transmission member connected to the shaft end portion of the rotating shaft, the number of parts is small. And is easy to assemble.

  Further, when the torque limiter mechanism is operated, the elastic piece is held in a non-contact state with respect to each of the drive disk and the torque transmission member on the side where the protruding piece portion is formed and the pulley. Generation of abnormal noise due to contact can be reliably prevented.

A longitudinal sectional view showing an embodiment of a power transmission device according to the present invention Right side view of FIG. A longitudinal sectional view showing the operating state of the torque limiter mechanism Right side view of FIG. (A) is a perspective view which shows the natural state of the torque transmission member which forms a torque limiter mechanism, (b) is a perspective view which shows the elastic deformation state of the elastic piece of (a). (A) is an expanded sectional view of the rotation engagement part formed in the elastic contact part of a press-contact piece part and a protrusion piece part, (b) is sectional drawing which shows the other example of a rotation engagement part. (A) is sectional drawing which shows another example of a rotation engaging part, (b) is sectional drawing along the VII-VII line of (a) A longitudinal sectional view showing another embodiment of the power transmission device according to the present invention Right side view of FIG. A longitudinal sectional view showing the operating state of the torque limiter mechanism Right side view of FIG. The perspective view of the torque limiter mechanism part shown in FIG. The perspective view which shows the operating state of a torque limiter mechanism Sectional drawing of the state which provided the rotation engaging part between the press-contacting piece part shown in FIG. 12, and a protrusion piece part (A) is sectional drawing which shows the other example of a rotation engaging part, (b) is sectional drawing along the XV-XV line of (a).

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. As shown in FIGS. 1 and 2, the power transmission device includes a pulley 10 to which power from an engine (not shown) is transmitted, a rotating shaft 21 of an automobile auxiliary machine 20, and a mutual connection between the pulley 10 and the rotating shaft 21. The torque limiter mechanism 30 is provided between the pulley 10 and the rotation of the pulley 10 so as to transmit the rotation to the rotation shaft 21 and cut off the rotation transmission from the pulley 10 to the rotation shaft 21 when the rotation load of the rotation shaft 21 increases.

  The pulley 10 includes a belt guide wheel 11, an annular plate 12 provided on the inner periphery of the belt guide wheel 11, and a cylindrical boss portion 13 provided on the inner periphery of the annular plate 12. A pair of flanges 14 are provided on both sides of the outer circumference of the belt guide wheel 11, and a plurality of V-shaped grooves 15 around which the V-belt is wound are provided between the pair of flanges 14.

  A bearing housing 16 is incorporated inside the boss portion 13. The bearing housing 16 is secured by an annular projecting portion 13 a provided on the inner periphery of one end of the boss portion 13. The bearing housing 16 is prevented from rotating by a serration 17 formed on the outer periphery of one end and the inner periphery of one end of the boss portion 13, and a rolling bearing 18 is incorporated in the bearing housing 16.

  Here, a double row ball bearing is employed as the rolling bearing 18. The rolling bearing 18 is press-fitted into a cylindrical pulley support shaft 23 provided in the housing 22 of the automobile auxiliary machine 20 and is prevented from being removed by a retaining ring 24 attached to the outer periphery of the end of the pulley support shaft 23.

  Here, a compressor for an air conditioner is employed as the automobile auxiliary machine 20. The pulley support shaft 23 provided on the housing 22 of the automobile auxiliary machine 20 is provided coaxially with the rotary shaft 21, and the pulley 10 is supported rotatably about the pulley support shaft 23.

  The torque limiter mechanism 30 includes a drive disk 31 connected to the pulley 10 and a torque transmission member 41 attached to the shaft end portion of the rotary shaft 21. The drive disk 31 is disposed so as to face the outer surface of the pulley 10 at an interval, and is provided coaxially with the rotary shaft 21.

  The drive disk 31 has an annular shape, and its inner diameter surface 32 is a tapered surface. Further, the drive disk 31 is provided with a plurality of elastic piece insertion portions 33 that are directed radially outward from the inner diameter surface 32 at equal angles in the circumferential direction, and between the adjacent elastic piece insertion portions 33, fan-shaped protrusions 34 are provided. Is provided. The elastic piece insertion portion 33 is a rectangular hole, and the three elastic piece insertion portions 33 are formed at intervals of 120 °. However, the number of the elastic piece insertion portions 33 is limited to this. is not.

  The drive disk 31 is coupled to the pulley 10 via a coupling mechanism 35. The connection mechanism 35 has a plurality of connection pins 36 protruding from the outer periphery of the drive disk 31, and the pulley 10 is provided with pin holes 37 into which the connection pins 36 are inserted. The pin holes 37 and the connection pins 36 are provided. An elastic member 38 such as rubber is incorporated between the opposed portions.

  As shown in FIG. 5, the torque transmission member 41 is provided with a disc portion 43 at one end portion of the cylindrical portion 42, and a plurality of elastic pieces 44 are provided at the outer peripheral portion of the disc portion 43. The number of elastic pieces 44 is the same as the number of elastic piece insertion portions 33 (see FIG. 2) formed on the drive disk 31. Further, the elastic pieces 44 are arranged in the same manner as the elastic piece insertion portions 33 and are sized so as to be inserted into the respective elastic piece insertion portions 33.

  The elastic piece 44 is formed with an inclined piece 45 and a pressure contact piece 46 formed by bending at the tip of the inclined piece 45, and the bending direction of the pressure contact piece 46 is opposite to the bending direction of the inclined piece 45. It is said that.

  The torque transmission member 41 having the above configuration is attached to the shaft end portion of the rotating shaft 21 as shown in FIG. At the time of attachment, the cylindrical portion 42 is fitted to the small diameter shaft portion 25 provided at the shaft end portion of the rotary shaft 21, the washer 47 is overlaid on the surface of the disk portion 43, and the small diameter shaft is penetrated through the washer 47. A bolt 49 is screwed into a screw hole 48 formed in the shaft end surface of the portion 25 and tightened.

  In order to strengthen the connection between the torque transmission member 41 and the rotary shaft 21, a serration 26 is provided between the fitting surfaces of the small diameter shaft portion 25 and the cylindrical portion 42, so that the small diameter shaft portion 25 and the cylindrical portion 42 are relatively moved. It is preventing rotation.

  Here, FIG. 1 shows a rotation transmission state in which the torque transmission member 41 transmits the rotation of the drive disk 31 to the rotary shaft 21, and the inclined piece portion 45 of the elastic piece 44 is in elastic contact with the inner diameter surface of the drive disk 31, The pressure contact piece 46 presses the outer surface of the protruding piece 34 of the drive disk 31. FIG. 5B shows a rotation transmission state of the torque transmission member 41, and each of the plurality of elastic pieces 44 is in an elastically deformed state.

  On the other hand, FIG. 3 shows a state in which the torque transmission member 41 is blocked from transmitting the rotation from the drive disk 31 to the rotary shaft 21, and in this blocked state, the elastic piece 44 of the torque transmission member 41 is in a natural state. The provided inclined piece portion 45 and pressure contact piece portion 46 are accommodated in a space formed between the boss portion 13 of the pulley 10 and the opposed portion of the drive disk 31, and are in a non-contact state with respect to the pulley 10 and the drive disk 31. It is said that.

  In forming the rotation transmission state as shown in FIG. 1, as shown in FIG. 3, after the torque transmission member 41 is attached to the shaft end portion of the rotary shaft 21, the torque transmission member 41 and the drive disk 31 are rotated relative to each other. 4, the elastic piece 44 and the elastic piece insertion portion 33 are aligned, and in the alignment state, the elastic piece 44 is elastically deformed and inserted into the elastic piece insertion portion 33, and the pressure contact piece portion 46. The torque transmission member 41 and the drive disk 31 are rotated relative to each other in a state where the elastic member 44 is pulled out on the outer surface of the drive disk 31, and the elastic piece 44 is released from being held in a state where the pressure contact piece portion 46 faces the protruding piece portion 34.

  As shown in FIG. 1, the engagement between the projecting piece portion 34 of the drive disk 31 and the pressure contact portion 46 of the torque transmission member 41 is released when the rotational load of the rotary shaft 21 exceeds a set value. A rotation engaging portion 50 is provided.

  As shown in FIG. 6A, the rotation engagement portion 50 includes an engagement protrusion 51 formed on the protrusion piece portion 34 and a recess 52 provided on the pressure contact piece portion 46. As the engaging protrusion 51, a frustoconical shape is shown in FIG. 6A, but it is not limited to this. For example, as shown in FIG. 6B, it may be a semicircular one. Or as shown to Fig.7 (a), (b), the cross-sectional shape of the circumferential direction may be made into circular arc shape. In any case, the recess 52 is shaped to fit the engagement protrusion 51.

  In FIGS. 6A and 6B and FIGS. 7A and 7B, a concave portion may be provided in the projecting piece portion 34, and an engaging protrusion may be provided in the pressure contact piece portion 46.

  The power transmission device shown in the embodiment has the above-described structure. As shown in FIG. 1, the pressing piece 46 of the elastic piece 44 formed on the torque transmission member 41 is in elastic contact with the protruding piece 34 of the drive disk 31. When the pulley 10 rotates in a state where the engagement protrusion 51 of the rotation engagement portion 50 provided at the contact portion engages with the recess 52, the rotation rotates via the drive disk 31 and the torque transmission member 41. It is transmitted to the shaft 21, and the rotating shaft 21 rotates in the same direction as the pulley 10, so that the automobile auxiliary machine 20 operates.

  When the rotational load of the rotary shaft 21 is increased due to trouble or the like in the operating state of the automobile auxiliary machine 20, the contact portion between the pressure contact piece portion 46 of the elastic piece 44 and the projecting piece portion 34 of the drive disk 31 in the torque transmission member 41. Slip occurs, the drive disk 31 and the torque transmission member 41 rotate relative to each other, and the engagement between the engagement protrusion 51 and the recess 52 of the rotation engagement portion 50 is released.

  When the positions of the elastic piece 44 and the elastic piece insertion portion 33 coincide with each other due to the relative rotation of the drive disk 31 and the torque transmission member 41, the elastic piece 44 moves the elastic piece insertion portion 33 by its own restoring elasticity. As shown in FIG. 3, the drive disk 31 and the torque transmission member 41 are disconnected, the rotation transmission from the pulley 10 to the rotary shaft 21 is cut off, and the pulley 10 and the drive disk 31 are disconnected. Rotates freely. The free rotation of the pulley 10 prevents the belt on the pulley 10 from being over-tensioned and damaged.

  In the state where the rotation transmission is interrupted as shown in FIG. 3, the elastic piece 44 that has returned to its natural state due to its own restoring elasticity is held in a non-contact state with respect to the pulley 10 and the drive disk 31, so that the rotation is stopped. Does not cause any abnormal noise.

  In the power transmission device shown in FIG. 1, the torque limiter mechanism 30 is formed by two parts of the drive disk 31 coupled to the pulley 10 and the torque transmission member 41 coupled to the shaft end portion of the rotary shaft 21. The number of parts is small, which is advantageous in terms of cost, and can be easily assembled.

  8 and 9 show another example of the torque limiter mechanism 30. FIG. In this example, a torque limiter mechanism 30 is formed by an annular drive disk 31 and a disk-shaped torque transmission member 41. The drive disk 31 is coupled to the annular plate 12 of the pulley 10 via a coupling mechanism 35. Since the coupling mechanism 35 is the same as the coupling mechanism 35 shown in FIG. 1, the same components are denoted by the same reference numerals and description thereof is omitted.

  As shown in FIG. 13, on the inner periphery of the drive disk 31, two sets of elastic pieces 60a, 60b that are adjacent to each other in the circumferential direction are provided at equal angles, and each set of elastic pieces 60a, An inclined piece 61 is provided at 60b, and a pressure contact piece 62 is provided at the tip of the inclined piece 61. The pressure contact piece 62 is bent in the same direction as the inclined piece 61, and the inclined pieces of the elastic pieces 60a and 60b. The bending direction of the part 61 is the opposite direction.

  The disk-shaped torque transmission member 41 has a cylindrical portion 70 on the shaft center, and the cylindrical portion 70 is fitted to the small diameter shaft portion 25 of the rotating shaft 21 and is rotated by a serration 71 provided in the fitting portion. It is fixed to the rotary shaft 21 via bolts 49 that are stopped and screwed into the screw holes 48 of the washer 47 and the small-diameter shaft portion 25.

  The torque transmission member 41 is provided on the same plane as the drive disk 31. On the outer periphery of the torque transmission member 41, an elastic piece insertion portion 72 into which each of the elastic pieces 60a, 60b as a pair can be inserted is provided at an equal angle in the circumferential direction corresponding to each elastic piece 60a, 60b. A projecting piece portion 73 is provided between the adjacent elastic piece insertion portions 72.

  When the torque is transmitted between the drive disk 31 and the torque transmitting member 41, the projecting piece 73 is formed from both sides by the pressure contact piece 62 of the elastic pieces 60a and 60b as a pair, as shown in FIGS. It is pinched elastically. When the elastic pieces 60a, 60b forming a pair face the elastic piece insertion portion 72, the elastic pieces 60a, 60b return to the natural state shown in FIGS. 10 and 13 by their own restoring elasticity, and are in a non-contact state with respect to the torque transmission member 41 in the natural state. Is done.

  As shown in FIGS. 8 and 9, in a state in which the pressing pieces 62 of the plurality of sets of elastic pieces 60 a and 60 b provided on the inner periphery of the drive disk 31 sandwich the protruding piece 73 of the torque transmission member 41 from both sides. When the pulley 10 rotates, the rotation is transmitted to the rotating shaft 21 via the drive disk 31 and the torque transmitting member 41, and the rotating shaft 21 rotates in the same direction as the pulley 10 to operate the automobile auxiliary machine 20.

  When the rotational load of the rotary shaft 21 increases due to troubles or the like in the operating state of the automobile auxiliary machine 20, the elasticity of the pressure contact piece portion 62 of the elastic pieces 60a and 60b and the protruding piece portion 73 of the torque transmission member 41 becomes a pair. Slip occurs at the contact portion, and the drive disk 31 and the torque transmission member 41 rotate relative to each other.

  When the positions of the elastic pieces 60a and 60b and the elastic piece insertion portion 72 coincide with each other due to the relative rotation of the drive disk 31 and the torque transmitting member 41, the elastic pieces 60a and 60b are elastic pieces by their own restoring elasticity. As shown in FIG. 10, the drive unit 31 is released from the insertion portion 72 to return to the natural state, the connection between the drive disk 31 and the torque transmission member 41 is released, and the rotation transmission from the pulley 10 to the rotary shaft 21 is interrupted. And the drive disk 31 rotates freely. The free rotation of the pulley 10 prevents the belt on the pulley 10 from being over-tensioned and damaged.

  In the state of interrupting the rotation transmission shown in FIG. 10, the elastic pieces 60 a and 60 b that have returned to the natural state due to their own restoring elasticity are held in a non-contact state with respect to the torque transmission member 41. There is no such thing as generating noise.

  Since the torque limiter mechanism 30 shown in FIGS. 8 and 9 is also composed of two parts, the drive disk 31 and the torque transmission member 41, the number of parts is small, which is advantageous in terms of cost and can be easily assembled.

  8 and 9, the drive disk 31 is provided with the elastic pieces 60a and 60b, and the torque transmission member 41 is provided with the elastic piece insertion portion 72 and the projecting piece portion 73. 31 may be provided with an elastic piece insertion portion and a protruding piece portion, and the torque transmission member 41 may be provided with an elastic piece.

  As shown in FIG. 14, the rotary engagement portion 50 may be provided at the pressure contact portion 62 of the elastic pieces 60 a and 60 b and the pressure contact portion 73 of the torque transmission member 41 in the drive disk 31. In FIG. 14, as the rotation engagement portion 50, the torque transmission member 41 is provided with a hemispherical engagement protrusion 51, and the press contact piece portion 62 is provided with a recess 52 that matches the engagement protrusion 51. 15 (a) and 15 (b), the engagement protrusion 51 may have a circular cross-sectional shape in the circumferential direction, and the recess 52 may have a shape that fits the engagement protrusion 51.

  As described above, if the rotation engagement portion 50 is provided, the torque limiter mechanism 30 malfunctions due to the relative rotation of the drive disk 31 and the torque transmission member 41 due to fluctuations in the rotational torque applied to the pulley 10. Can be prevented.

DESCRIPTION OF SYMBOLS 10 Pulley 20 Automobile accessories 21 Rotating shaft 23 Pulley support shaft 30 Torque limiter mechanism 31 Drive disk 33 Elastic piece insertion part 34 Projection piece part 36 Connection pin 37 Pin hole 38 Elastic member 41 Torque transmission member 44 Elastic piece 45 Inclination piece part 46 Pressure contact piece 50 Rotating engagement part 51 Engagement protrusion 52 Recess 60a Elastic piece 60b Elastic piece 61 Inclined piece part 62 Pressure contact piece part 72 Elastic piece insertion part 73 Projection piece part

Claims (5)

A pulley supported rotatably about a pulley support shaft provided coaxially with the rotation axis of the automobile auxiliary machine, and provided between the pulley and the rotation shaft to transmit the rotation of the pulley to the rotation shaft. In a power transmission device having a torque limiter mechanism that interrupts rotation transmission from the pulley to the rotation shaft when the rotation load of the rotation shaft exceeds a set value,
The torque limiter mechanism is mounted on the shaft end portion of the rotating shaft, and is arranged to face the outer surface of the pulley and is coupled to the pulley so as to rotate integrally therewith. A plurality of elastic pieces provided on one of the drive disk and the torque transmission member, and an elastic piece insertion portion into which each elastic piece can be inserted on the other, and adjacent elastic pieces. A protruding piece is provided between the insertion parts,
The elastic piece is provided with an inclined piece portion, and a pressure contact piece portion is provided at a tip of the inclined piece portion, and the inclined piece portion is not in a natural state with respect to a member having the pulley and the protruding piece portion. The power transmission device is characterized in that the inclination angle is a contact angle, the inclined piece portion is elastically deformed and inserted into the elastic piece insertion portion, and the pressure contact piece portion is elastically contacted with the protruding piece portion.   2. The power transmission device according to claim 1, wherein a rotation engagement portion that is disengaged when a rotation load of the rotation shaft exceeds a set value is provided in the elastic contact portion between the pressure contact piece portion and the protrusion piece portion. .   The rotation engagement portion is composed of an engagement protrusion formed on the protrusion piece portion and a recess provided on the pressure contact piece portion, and the engagement protrusion is a kind of a truncated cone shape, a semicircular shape, and an arc shape. The power transmission device according to claim 2, wherein the recess has a shape corresponding to the engagement protrusion.   The torque transmission member has a disc shape, the torque transmission member and the drive disk are provided on the same surface, and a plurality of sets of elastic pieces are provided adjacent to each other in the circumferential direction as a set, The power transmission according to any one of claims 1 to 3, wherein the inclined piece portions of the elastic pieces forming the set are inclined in opposite directions, and the pressure contact piece portions are in elastic contact with the protruding piece portions sandwiched from both sides. apparatus.   A plurality of connecting pins project from the outer periphery of the drive disk, and the pulley is provided with pin holes into which the connecting pins are inserted, and an elastic member is interposed between the pin holes and the facing portions of the connecting pins. The power transmission device according to any one of claims 1 to 4.

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