JP2019120368A - Power transmission device - Google Patents

Abstract

To provide a power transmission device which can decrease the tension of a drive belt.SOLUTION: When transmission torque is instantaneously increased while maintaining a state that a rotating shaft 161 of a compressor 16 is rotatable, a slide occurs at a torque limiter 24. Therefore, the limiter operation torque of the torque limiter 24 is set low compared with the case that the limiter operation torque is set so that the slide of the torque limiter 24 does not occur at a failure of the compressor 16. The tension of a drive belt 18 can be thereby reduced. When the instantaneous increase of the transmission torque of a power transmission device 10 is finished, the slide of the torque limiter 24 is eliminated. Accordingly, even if the slide occurs at the torque limiter 24 when the transmission torque becomes instantaneously large while maintaining a non-failed state of the compressor 16, the drive of the compressor 16 is not substantially hindered.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a power transmission device that transmits rotational power from a drive belt to a driven body.

  As a power transmission device of this type, for example, a power transmission device described in Patent Document 1 is conventionally known. The power transmission device described in Patent Document 1 is configured as a torque limiter, and is provided in a power transmission path between a drive belt driven by an engine and a rotation shaft of a compressor that is a driven body. When a torque equal to or greater than a predetermined threshold, that is, an overload torque is applied to the power transmission device from the drive belt, components included in the power transmission device to transmit power are broken. For example, overload torque may occur if the compressor fails for some reason and becomes unrotatable.

  By breaking the components described above, the power transmission disconnects power transmission from the drive belt to the rotary shaft of the compressor. And, by interrupting the power transmission, damage to the drive belt is avoided. Furthermore, if there is an accessory driven by the drive belt with the compressor, the failure of the accessory is also avoided.

Patent No. 3691743

  In the power transmission device of Patent Document 1 configured as a torque limiter, as described above, power transmission is interrupted by breakage of a component. Therefore, it is necessary to prevent the power transmission from being interrupted even though the compressor has not failed. The reason is that the power transmission device of Patent Document 1 can not transmit power to the compressor after the component parts are broken once. Therefore, in the power transmission device of Patent Document 1, the threshold value of the torque at which the power transmission is interrupted, that is, the limiter operation torque at which the torque limiter operates, is the maximum value of the transmission torque transmitted when the compressor has not failed. Need to set higher than.

  Here, the non-fault torque, which is the transfer torque transmitted when the compressor has not failed, changes according to the operating condition of the compressor. For example, if the compressor is an air conditioning compressor, the higher the heat load of the air conditioner, the larger the average value of the transmission torque transmitted by the power transmission device. In addition, when the rotation speed of the compressor becomes the resonance rotation speed, the fluctuation range of the transmission torque is expanded. In addition, if the operating load of the engine is high, the fluctuation of the transfer torque due to the rotational fluctuation of the engine is also added. The non-fault torque described above is an instantaneous value of the transfer torque, so the non-fault torque becomes larger as the fluctuation range of the transfer torque is expanded. In addition, when the compressor is started up in a state in which the refrigerant in the air conditioner is liquefied in the suction space or piping of the compressor, the compressor compresses the liquid refrigerant, resulting in the compression of the liquid refrigerant. As a result, a liquid compression torque that increases momentarily is generated.

  As described above, since the non-fault torque fluctuates due to various factors and it is difficult to accurately predict the maximum value of the non-fault torque, the lower limit value of the variation of the limiter operating torque is a non-fault which is analogized in advance It is necessary to set a value obtained by multiplying the maximum value of the torque by a sufficient safety factor.

  On the other hand, in order to avoid damage to the drive belt and a defect in the accessory driven by the compressor together with the compressor, the belt slip torque at which the drive belt slips against the pulley exceeds the upper limit value of the variation of the limiter operating torque. There is a need.

  From such a thing, in the power transmission device of Patent Document 1, in order to prevent the power transmission from being interrupted even though the compressor is not broken, and also to prevent the damage of the drive belt, the belt slip torque Need to be high. Then, in order to increase the belt slip torque, it is necessary to increase the belt tension of the drive belt.

  However, as the belt tension increases, the power loss increases in the compressor and accessory bearings rotated by the drive belt. Further, if the belt tension is increased, the width of the drive belt is increased to increase the rigidity of the drive belt, the width of the pulley is also increased, and the rigidity of the pulley also needs to be ensured. That is, increasing the belt tension leads to an increase in the weight of the drive belt and its peripheral parts.

  Such an increase in belt tension may lead to various disadvantages such as an increase in power loss and an increase in weight. Moreover, although the to-be-driven apparatus which receives the motive power from a drive belt was mentioned above as a compressor, it is thought that the demerit may be produced even if a to-be-driven apparatus is apparatuses other than a compressor. As a result of the inventor's detailed examination, the above was found out.

  An object of the present invention is to provide a power transmission device capable of reducing the tension of a drive belt.

In order to achieve the above object, the power transmission device according to claim 1 is:
A power transmission device for transmitting power from a drive belt (18) to a driven body for rotating the driven body (161),
A pulley (20) on which a drive belt is wound and rotationally driven by the drive belt;
A torque limiter (24) which is provided in a power transmission path between a pulley and a driven body and slips when the transmission torque (Tr) transmitted from the pulley to the driven body exceeds a predetermined torque threshold value. Equipped with
When the transmission torque instantaneously increases while maintaining the rotatable state of the driven body, slippage occurs in the torque limiter,
If it is settled that the transmission torque is increased momentarily, the slip of the torque limiter is eliminated.

  As described above, when the transmission torque is momentarily increased while maintaining the rotatable state of the driven body, slippage occurs in the torque limiter, and therefore, compared with the power transmission device of Patent Document 1 The torque threshold in the torque limiter is set low. Therefore, it is possible to lower the tension of the drive belt as compared with the case where the power transmission device of Patent Document 1 is used.

  Further, as described above, it is rare that the transmission torque instantaneously increases while maintaining the rotatable state of the driven body, and if it is settled that the transmission torque instantaneously increases, the slip of the torque limiter There is no substantial obstacle to the drive of the driven body.

  In addition, each code | symbol in the parentheses described in the claim and this column is an example which shows the correspondence with the specific content as described in embodiment mentioned later.

BRIEF DESCRIPTION OF THE DRAWINGS It is a schematic block diagram of the refrigerating-cycle apparatus provided with the compressor which receives the motive power of an engine via the power transmission device of 1st Embodiment. It is the fragmentary sectional view which carried out cross-sectional illustration of the principal part of the power transmission device of 1st Embodiment. In the first embodiment, it is a time chart showing transition of the number of rotations of the compressor and transition of the transmission torque transmitted from the pulley to the rotation shaft of the compressor when the compressor whose rotation has been stopped is started. is there. FIG. 7 is a time chart showing the transition of the transmission torque and the number of revolutions of the compressor when the compressor is activated in the same condition as FIG. 3 using the power transmission device of the comparative example, and a diagram corresponding to FIG. 3 It is. It is the fragmentary sectional view which carried out cross-sectional illustration of the principal part of the power transmission device of 2nd Embodiment, Comprising: It is a figure corresponded in FIG. It is VI arrow line view in FIG. It is sectional drawing which showed the VII-VII cross section of FIG. It is the fragmentary sectional view which carried out cross-sectional illustration of the principal part of the power transmission device of 3rd Embodiment, Comprising: It is a figure corresponded in FIG. FIG. 9 is a partially enlarged view of a portion IX in FIG. 8. It is the perspective view which showed the general | schematic shape of the tolerance ring which the power transmission device of 3rd Embodiment has. It is the fragmentary sectional view which carried out cross-sectional illustration of the principal part of the power transmission device of 4th Embodiment, Comprising: It is a figure corresponded in FIG. FIG. 12 is a partially enlarged view of the XII portion of FIG.

  Hereinafter, each embodiment will be described with reference to the drawings. In the following embodiments, parts identical or equivalent to each other are denoted by the same reference numerals in the drawings.

First Embodiment
The power transmission device 10 of the present embodiment is mounted on a vehicle. Then, as shown in FIG. 1, the power transmission device 10 transmits the power from the engine 12 to the compressor 16. That is, in the present embodiment, the driven device that receives power via the power transmission device 10 is the compressor 16. The drive source generating power for rotating the rotation shaft 161 (see FIG. 2) of the compressor 16 is the engine 12.

  As shown in FIG. 1, the compressor 16 constitutes a part of the refrigeration cycle apparatus 14 in which the refrigerant circulates, compresses the refrigerant, and discharges the refrigerant after compression. The refrigeration cycle apparatus 14 is for air conditioning of a passenger compartment, and includes, in addition to the compressor 16, a condenser 141, an expansion valve 142, an evaporator 143, and the like. In the refrigeration cycle apparatus 14, the compressor 16, the condenser 141, the expansion valve 142, and the evaporator 143 are connected to form an annular refrigerant circuit. Therefore, the refrigerant discharged from the compressor 16 flows in the order of the condenser 141, the expansion valve 142, and the evaporator 143, and the refrigerant flowing out of the evaporator 143 is sucked into the compressor 16.

  As shown in FIG. 2, the compressor 16 has a rotating shaft 161, a housing 162 and a boss portion 163. The housing 162 forms the outer shell of the compressor 16, and a plurality of mechanical components for compressing the refrigerant are accommodated in the housing 162.

  The rotary shaft 161 of the compressor 16 protrudes from the housing 162 to one side of the axial direction DRa of the compressor axial center CL, and rotates around the compressor axial center CL as a predetermined axial center. Then, the power transmission device 10 transmits the motive power for rotating the rotating shaft 161 as the driven body from the drive belt 18 to the rotating shaft 161. In other words, as shown in FIG. 1, the power transmission system 10, the drive belt 18 and the pulley 121 of the engine 12 transmit power of the engine 12 from the engine 12 to the rotation shaft 161 of the compressor 16. Included in 19.

  Note that, as shown in FIG. 2, in the present embodiment, the axial direction DRa of the rotation shaft 161 of the compressor 16, that is, the axial direction DRa of the compressor axial center CL is referred to as a compressor axial direction DRa. Further, the radial direction DRr of the rotary shaft 161, that is, the radial direction DRr of the compressor axial center CL is referred to as a compressor radial direction DRr.

  The boss 163 of the compressor 16 is fixed to the housing 162. That is, the boss portion 163 and the housing 162 of the compressor 16 are non-rotational members that do not rotate.

  Further, the boss portion 163 is formed to project from the housing 162 in the same direction as the rotation shaft 161. The boss portion 163 has a cylindrical shape, and is formed around the rotation shaft 161 at a distance from the rotation shaft 161 in the compressor radial direction DRr.

  The power transmission device 10 includes a pulley 20, a damper 22, and a torque limiter 24. The pulley 20, the damper 22 and the torque limiter 24 all rotate around the compressor axis CL.

  The pulley 20 is rotatably supported by the boss portion 163 of the compressor 16 via the bearing 26 and therefore rotates around the compressor axis CL. The bearing 26 may be a slide bearing but is a rolling bearing in the present embodiment.

  Further, a ring-shaped drive belt 18 is wound around the outer side in the radial direction of the pulley 20. The drive belt 18 is also wound around the pulleys 121 (see FIG. 1) of the engine 12, and a predetermined belt tension is applied so as not to slip on the respective pulleys. Thus, the pulley 20 of the power transmission device 10 is rotationally driven by the drive belt 18. That is, the power of the engine 12 is transmitted to the pulley 20 via the drive belt 18.

  The damper 22 suppresses transmission of rotational fluctuation of the compressor 16 to the drive belt 18 and transmission of rotational fluctuation of the engine 12 transmitted to the pulley 20 via the drive belt 18 to the rotation shaft 161 of the compressor 16. doing. Specifically, the damper 22 has an outer fitting 221, an elastic member 222, and an inner fitting 223.

  The outer bracket 221 is fixed to the pulley 20 by a plurality of bolts 221a. Accordingly, the damper 22 rotates integrally with the pulley 20 about the compressor axis CL.

  The elastic member 222 of the damper 22 is made of a resilient elastic material such as rubber or elastomer. The elastic member 222 is provided between the outer fitting 221 and the inner fitting 223. The elastic member 222 is joined to the outer fitting 221 on the outer peripheral side of the elastic member 222 and is joined to the inner fitting 223 on the inner peripheral side.

  The inner metal fitting 223 of the damper 22 includes a joint portion 223a to which the elastic member 222 is joined, and a damper friction plate portion 223b. The damper friction plate 223 b is extended so as to protrude radially inward from the joint 223 a. The damper friction plate portion 223b has a disk shape having a thickness direction in the compressor axial direction DRa, and a damper penetrating through the damper friction plate portion 223b in the compressor axial direction DRa at the central portion of the damper friction plate portion 223b. A hole 223c is formed. The damper friction plate 223 b is a part of the damper 22 but is also included in the torque limiter 24. The damper friction plate portion 223 b is a drive portion 24 a of the torque limiter 24 that rotates with the pulley 20.

  The torque limiter 24 is provided in a power transmission path between the pulley 20 and the rotation shaft 161 of the compressor 16. That is, the torque limiter 24 rotates around the compressor axis CL, and transmits the power of the engine 12 transmitted to the pulley 20 to the rotation shaft 161 of the compressor 16.

  Specifically, the torque limiter 24 includes a first friction material 241, a second friction material 242, an inner hub 243, a disc spring 244, and a retaining ring 245. The first friction material 241 and the second friction material 242 are disk-shaped plate members whose thickness direction is the compressor axial direction DRa.

  The first friction member 241 and the second friction member 242 are arranged side by side in the compressor axial direction DRa so as to sandwich the damper friction plate portion 223b therebetween. Specifically, the first friction material 241 is disposed on one side of the damper friction plate portion 223b in the compressor axial direction DRa, and is in contact with the damper friction plate portion 223b. The second friction material 242 is disposed on the other side of the damper friction plate portion 223b in the compressor axial direction DRa, and is in contact with the damper friction plate portion 223b.

  The inner hub 243 has an axial shaft portion 243 a extending in the compressor axial direction DRa, and a flange portion 243 b protruding like a collar outward in the radial direction from the shaft portion 243 a. The shaft portion 243a is formed with a fitting hole 243c in which the rotary shaft 161 of the compressor 16 is fitted in the compressor axial direction DRa.

  The rotary shaft 161 fitted in the fitting hole 243 c is connected to the shaft portion 243 a of the inner hub 243 so as to be relatively non-rotatable, for example, by spline fitting. Furthermore, the rotating shaft 161 is fixed to the shaft portion 243 a of the inner hub 243 by a bolt 27. Therefore, the rotary shaft 161 can not move relative to the shaft portion 243 a of the inner hub 243 in the compressor axial direction DRa. In short, the inner hub 243 rotates integrally with the rotating shaft 161.

  Further, the shaft portion 243 a of the inner hub 243 is inserted into the radially inner side of each of the first friction material 241 and the second friction material 242. The first friction member 241 and the second friction member 242 are non-rotatably connected to the shaft portion 243 a of the inner hub 243 by spline fitting, for example. That is, the first friction material 241 and the second friction material 242 rotate with the inner hub 243 around the compressor axis CL. The first friction member 241, the second friction member 242, and the inner hub 243 form a driven portion 24b of the torque limiter 24 that rotates with the rotation shaft 161 of the compressor 16.

  In the power transmission device 10, the power of the engine 12 is transmitted from the drive belt 18 to the pulley 20, the damper 22, the two friction members 241 and 242, the inner hub 243, and the rotation shaft 161 in this order. When slippage occurs in the torque limiter 24 as described later, power transmission is limited between the two friction members 241 and 242 and the inner hub 243.

  The flange portion 243 b of the inner hub 243 is disposed on the other side of the second friction member 242 in the compressor axial direction DRa and is in contact with the second friction member 242. Therefore, the flange portion 243 b prevents the second friction material 242 from moving to the other side of the inner hub 243 in the compressor axial direction DRa.

  The disc spring 244 is disposed on one side of the first friction member 241 in the compressor axial direction DRa. The radially inner end of the disc spring 244 is locked by a snap ring 245 fitted in the groove of the shaft portion 243 a of the inner hub 243 so as not to move to one side in the compressor axial direction DRa. Further, the radially outer end of the disc spring 244 is in contact with the first friction material 241.

  Further, the disc spring 244 is compressed between the retaining ring 245 and the first friction member 241 in the compressor axial direction DRa. Therefore, the disc spring 244 biases the first friction member 241, the damper friction plate portion 223b, and the second friction member 242 to the other side in the compressor axial direction DRa. The flange portion 243b of the inner hub 243 opposes the compressor axial direction DRa with respect to the biasing force (in other words, pressing force) of the disc spring 244.

  The first friction member 241 and the second friction member 242 are pressed against the damper friction plate portion 223b by the biasing force of the disc spring 244 and are in frictional contact with the damper friction plate portion 223b. That is, the disc spring 244 functions as a pressing member that presses the first friction member 241 and the second friction member 242 against the damper friction plate portion 223b.

  Specifically, in the damper friction plate portion 223b, the side surface facing one side of the compressor axial direction DRa is formed as a first drive side friction surface 223d, and the side surface facing the other side of the compressor axial direction DRa is a second drive It is formed as a side friction surface 223e. Further, of the first friction material 241, a side surface facing the first drive-side friction surface 223d in the compressor axial direction DRa and opposed thereto is formed as a first driven-side friction surface 241a. At the same time, a side surface of the second friction material 242 which faces the second drive-side friction surface 223e in the compressor axial direction DRa and is opposed thereto is formed as a second driven-side friction surface 242a.

  Then, the first driven friction surface 241a is pressed against the first drive friction surface 223d by the biasing force of the disc spring 244, and the second driven friction surface 242a is pressed against the second drive friction surface 223e. There is. The torque limiter 24 is configured such that the friction between the first driven friction surface 241a and the first driving friction surface 223d and the friction between the second driven friction surface 242a and the second driving friction surface 223e. And transmit power.

  As described above, since power is transmitted by friction between a plurality of members, when the transmission torque Tr transmitted from the pulley 20 to the rotation shaft 161 of the compressor 16 becomes equal to or more than the predetermined torque threshold TL, the torque limiter Slippage occurs at 24. Specifically, with respect to the slip of the torque limiter 24, the first drive-side friction surface 223d slides in the circumferential direction of the rotary shaft 161 with respect to the first driven-side friction surface 241a, and the second drive-side friction surface 223e Is sliding in the circumferential direction of the rotating shaft 161 with respect to the second driven side friction surface 242a. In other words, the slip of the torque limiter 24 means that in the torque limiter 24, the damper friction plate portion 223 b rotates relative to the first friction member 241, the second friction member 242, and the inner hub 243.

  Specifically, since the damper friction plate portion 223b is on the drive side and the inner hub 243 and the like are on the driven side, when the torque limiter 24 slips, the damper friction plate portion 223b is the inner hub 243 etc. Rotate faster than. Alternatively, the damper friction plate 223b rotates but the inner hub 243 and the like do not rotate.

  Further, in the torque limiter 24, the limiter operating torque TL, which is the torque threshold value TL, is determined according to the biasing force of the disc spring 244, and increases as the biasing force of the disc spring 244 increases. Therefore, the limiter operating torque TL is preset according to the amount of elastic deformation of the disc spring 244.

  The limiter operating torque TL has a variation as shown by an arrow WT in FIG. 3 described later. That is, the limiter operating torque TL fluctuates within the fluctuation range WT of FIG. Further, in FIG. 3, the upper limit value La of the variation range WT of the limiter operating torque TL is indicated by an alternate long and short dash line La, and the lower limit Lb of the variation range WT of the limiter operating torque TL is indicated by an alternate long and short dash line Lb.

  Further, the amount of elastic deformation of the disc spring 244 is set such that the upper limit La of the variation range WT of the limiter operating torque TL is smaller than the belt slip torque Tsp at which the drive belt 18 slips relative to the pulley 20. This is to prevent the drive belt 18 from slipping on the pulley 20. In FIG. 3, the belt slip torque Tsp is indicated by a one-dot chain line Tsp.

  Furthermore, the amount of elastic deformation of the disc spring 244 is set such that the lower limit value Lb of the variation range WT of the limiter operating torque TL is larger than the steady transmission torque which is the transmission torque Tr that shifts steadily during driving of the compressor 16. It is also set. The frequent occurrence of the slip of the torque limiter 24 substantially hinders the operation of the compressor 16.

  Next, the magnitude of the limiter operating torque TL in the power transmission device 10 of the present embodiment will be described with reference to FIG. FIG. 3 shows the transition of the rotational speed Nc of the compressor 16 and the transition of the transmission torque Tr transmitted from the pulley 20 to the rotation shaft 161 of the compressor 16 when the compressor 16 which has been stopped rotating is activated. It is the time chart which showed. The transmission torque Tr is a torque that the power transmission device 10 transmits to the rotation shaft 161 of the compressor 16, and in short is a transmission torque of the power transmission device 10.

  In the time chart of the transmission torque Tr, a solid line Tra represents an average component of the transmission torque Tr. Further, a broken line Trp indicates a fluctuation component on the positive side of the transmission torque Tr, and a broken line Trm indicates a fluctuation component on the negative side of the transmission torque Tr. In other words, the broken line Trp indicates the maximum value of the instantaneous values of the transfer torque Tr, and the broken line Trm indicates the minimum value of the instantaneous values of the transfer torque Tr. In short, in FIG. 3, the transmission torque Tr fluctuates between the broken line Trp and the broken line Trm.

  The compressor 16 has been stopped for a long time while being stopped until time t1 in FIG. Then, the compressor 16 is activated at time t1. Therefore, the rotational speed Nc of the compressor 16 starts to rise from time t1.

  The rotational speed Nc of the compressor 16 reaches a resonant rotational speed Ncs at which resonance of the power transmission system 19 (see FIG. 1) occurs at time t2. After time t2, the rotational speed Nc of the compressor 16 further rises over the resonant rotational speed Ncs, and after a while becomes a constant rotational speed. Therefore, in FIG. 3, the rotatable state of the rotation shaft 161 of the compressor 16 is maintained from the beginning to the end without failure of the compressor 16.

  Looking at the transition of the transmission torque Tr of the power transmission device 10, the transmission torque Tr instantaneously increases at time t1. This is because the compressor 16 temporarily compressed the liquid refrigerant. That is, the case where the transmission torque Tr momentarily increases at time t1 is a case where the transmission torque Tr momentarily increases because the compressor 16 compresses the liquid phase refrigerant.

  Also, as indicated by the broken line Trp, the transmission torque Tr is instantaneously large at time t2. This is because the resonance of the power transmission system 19 temporarily occurs. That is, the case where the transmission torque Tr momentarily increases at time t2 is the case where the transmission torque Tr momentarily increases due to the resonance of the power transmission system 19.

  Specifically, the transfer torque Tr momentarily increased at time t1 and time t2 is equal to or higher than the limiter operating torque TL. That is, the transmission torque Tr has reached the limiter operating torque TL.

  Here, FIG. 3 shows the transition of the transmission torque Tr when the limiter operating torque TL is the lower limit value Lb of the variation range WT. For example, when the limiter operating torque TL varies within the variation range WT and becomes the upper limit value La of the variation range WT, the transmission torque Tr instantaneously increases to the upper limit value La at time t1. become. At time t2, a resonance torque T2r, which will be described later, is smaller than the upper limit value La, no slippage occurs in the torque limiter 24, and the transmission torque Tr instantaneously increases to the resonance torque T2r. As shown in FIG. 3, since the variation range WT of the limiter operating torque TL is set to be lower than the belt slip torque Tsp, the transmission torque Tr does not reach the belt slip torque Tsp in any way.

  As shown at time t1 and time t2 in FIG. 3, in the present embodiment, when the transfer torque Tr instantaneously increases while the rotatable state of the rotation shaft 161 of the compressor 16 is maintained, the torque is increased. Slippage has occurred in the limiter 24. That is, the damper friction plate portion 223b slides in the circumferential direction of the rotating shaft 161 with respect to the first and second friction members 241 and 242, whereby the torque limiter 24 causes the transmission torque Tr to exceed the limiter operating torque TL. To prevent it from

  Then, immediately after time t1, the compressor 16 finishes compressing the liquid refrigerant, and the transmission torque Tr becomes smaller than the lower limit value Lb of the variation range WT of the limiter operating torque TL due to the completion of the compression of the liquid refrigerant. , Has been steady again. Therefore, immediately after time t1, the torque limiter 24 loses its slip and the slip is lost, so that the inner hub 243 and the rotary shaft 161 of the compressor 16 begin to rotate together with the pulley 20 again.

  Further, immediately after time t2, the rotational speed Nc of the compressor 16 shifts from the resonant rotational speed Ncs. Then, as the rotational speed Nc deviates from the resonant rotational speed Ncs, the transmission torque Tr becomes smaller than the lower limit value Lb of the variation range WT of the limiter operating torque TL, and the steady state transition occurs again. Therefore, immediately after time t2, the torque limiter 24 loses its slip, and the slip is lost, so that the inner hub 243 and the rotary shaft 161 of the compressor 16 begin to rotate together with the pulley 20 again.

  As described above, the slip of the torque limiter 24 is eliminated if the transmission torque Tr instantaneously increases at any time immediately after time t1 and immediately after time t2. Therefore, the torque limiter 24 of the present embodiment is a self-restoring type torque limiter that returns to a state capable of transmitting power after slippage occurs in the torque limiter 24.

  Although FIG. 3 has been described taking the case where the compressor 16 is maintained in a non-failed state without failure as an example, there may be a case where the compressor 16 fails. If the compressor 16 fails, the rotary shaft 161 of the compressor 16 can not rotate. In that case, assuming that the torque limiter 24 is not provided and the pulley 20 is directly connected to the rotary shaft 161 of the compressor 16, the transmission torque Tr larger than that during compression and resonance of the liquid refrigerant described above is applied. Become. Therefore, in the power transmission device 10 of the present embodiment, even if the compressor 16 breaks down, the transmission torque Tr becomes, of course, equal to or higher than the limiter operating torque TL, so that slippage occurs in the torque limiter 24.

  As described above, when the compressor 16 breaks down and the torque limiter 24 slips, the damper friction plate portion 223b receives the first and second friction torques while the transmission torque Tr having the same magnitude as the limiter operation torque TL is applied. It slides in the circumferential direction of the rotating shaft 161 with respect to the friction members 241 and 242. By the continuation of this sliding, the damper friction plate portion 223b and the first and second friction members 241 and 242 wear with time, respectively, and the amount of elastic deformation of the disc spring 244 gradually decreases. The biasing force of the disc spring 244 also decreases. As a result, the transmission torque Tr applied to the rotation shaft 161 of the compressor 16 gradually decreases, and the torque limiter 24 eventually cuts off the torque transmission between the pulley 20 and the rotation shaft 161 of the compressor 16.

  As described above, according to the present embodiment, as shown in FIG. 2 and FIG. 3, the slip of the torque limiter 24 is eliminated if the transmission torque Tr of the power transmission device 10 is instantaneously increased. Therefore, even if slippage occurs in the torque limiter 24 when the transmission torque Tr momentarily increases while the non-fault state of the compressor 16 is maintained, the slippage occurs only rarely in practice. There is no substantial obstacle to the drive of 16.

  When the transmission torque Tr instantaneously increases while maintaining the rotatable state of the rotation shaft 161 of the compressor 16, slippage occurs in the torque limiter 24. Therefore, in comparison with, for example, the power transmission device of Patent Document 1, the limiter operating torque TL in the torque limiter 24 is set lower. Therefore, it is possible to lower the tension of the drive belt 18 as compared with the case where the power transmission device of Patent Document 1 is used.

  This will be described in detail using the power transmission device of the comparative example. The power transmission apparatus of the comparative example is a power transmission apparatus having a torque limiter that can not be restored itself, such as the power transmission apparatus of Patent Document 1. Therefore, in the power transmission device of the comparative example, it is necessary to avoid the situation where the power transmission is interrupted by the torque limiter even though the compressor 16 is not broken. Therefore, in the power transmission device of the comparative example, the limiter operation is performed so that no slippage occurs in the torque limiter even when the transmission torque Tr momentarily increases while the rotatable state of the rotation shaft 161 of the compressor 16 is maintained. Torque TL is set.

  That is, as shown in FIG. 4, the variation range WT of the limiter operating torque TL is larger than the non-fault maximum torque Trx whose lower limit Lb is the maximum value Trx of the transmission torque Tr in the non-fault state of the compressor 16 It is set to become. Specifically, the lower limit value Lb is a value obtained by multiplying the non-fault maximum torque Trx by a sufficient safety factor SF1 larger than one. Therefore, the variation range WT of the limiter operating torque TL in the comparative example is shifted to the larger side of the transmission torque Tr as compared with that of the present embodiment.

  Here, FIG. 4 exemplifies the liquid compression torque T1r when the compressor 16 compresses the liquid refrigerant as one of the maximum values of the transmission torque Tr, and in the comparative example, the liquid compression torque T1r is It corresponds to the maximum torque Trx at no failure. In addition to the liquid compression torque T1r, FIG. 4 also illustrates a resonance torque T2r when a resonance of the power transmission system 19 occurs as a maximum value of the transmission torque Tr. Although the magnitude relation between the resonance torque T2r and the liquid compression torque T1r differs depending on the actual device, the liquid compression torque T1r is larger than the resonance torque T2r in FIG.

  Note that the time chart of FIG. 4 shows the transition of the transmission torque Tr and the rotational speed Nc of the compressor 16 when the compressor 16 is started in the same situation as that of FIG. 3 using the power transmission device of the comparative example. ing. That is, in the time chart of FIG. 4, the same situation as the time chart of FIG. 3 is shown except that the power transmission device of the comparative example is used instead of the power transmission device 10 of this embodiment. Accordingly, in the time chart of FIG. 4, the rotation speed Nc of the compressor 16 changes in the same manner as in FIG. 3, the liquid compression torque T1r is generated at time t1, and the resonance torque T2r is generated at time t2. Further, in FIG. 3 described above, the circles indicating the liquid compression torque T1r and the resonance torque T2r are transcribed so as to indicate the same coordinates as in FIG.

  Further, as shown in FIG. 4, in the power transmission device of the comparative example as well as the power transmission device 10 of the present embodiment, the belt slip torque Tsp needs to exceed the upper limit value La of the variation range WT of the limiter operating torque TL. is there.

  Therefore, as can be understood by comparing FIG. 3 and FIG. 4, in the present embodiment, it is possible to lower the variation range WT of the limiter operating torque TL and the belt slip torque Tsp more than the comparative example. As a result, in the present embodiment, as described above, it is possible to lower the tension of the drive belt 18 as compared with the case where the power transmission device of Patent Document 1 is used. Also, if the tension of the drive belt 18 is reduced, the supporting load of the bearing 26 is reduced, and the power loss associated with the rotation of the pulley 20 can be reduced.

  Further, it is assumed that there is an accessory which is co-mounted on the drive belt 18 with the pulley 20 of the power transmission device 10 and is driven by the drive belt 18 together with the compressor 16. In that case, by reducing the tension of the drive belt 18, the supporting load (that is, the bearing load) of the bearing of the accessory can be reduced, and the power loss in the accessory can be reduced.

  In addition, when the tension of the drive belt 18 is reduced, the rigidity of the drive belt 18 can be reduced accordingly, so that, for example, the width of the drive belt 18 can be reduced. At the same time, in the case where there is the above-mentioned accessory to be engaged, the pulley width of the accessory can also be reduced. Since such a thing leads to weight reduction of the vehicles carrying compressor 16, it has a good influence also on a vehicle fuel consumption combined with the above-mentioned power loss becoming small. That is, it is possible to prevent the deterioration of the fuel efficiency of the vehicle.

  Further, according to the present embodiment, as shown in FIG. 2, the torque limiter 24 has a damper friction plate portion 223 b as a drive portion 24 a that rotates with the pulley 20. At the same time, the torque limiter 24 has first and second friction members 241 and 242 as a driven portion 24 b that rotates with the rotation shaft 161 of the compressor 16 and an inner hub 243. The damper friction plate portion 223b is formed with a first drive side friction surface 223d and a second drive side friction surface 223e. In addition, the first driven friction surface 241 a pressed against the first drive friction surface 223 d is formed on the first friction member 241, and the second friction member 242 is pressed against the second drive friction surface 223 e. The second driven side friction surface 242a is formed. The torque limiter 24 transmits power by the friction between the drive side friction surfaces 223 d and 223 e and the driven side friction surfaces 241 a and 242 a. When the torque limiter 24 slips, the drive-side friction surfaces 223 d and 223 e slide on the driven-side friction surfaces 241 a and 242 a, and the damper friction plate portion 223 b forms the first and second friction members 241 and 242 and the inner hub 243. It is to rotate relative to it.

  Therefore, the friction between the drive side friction surfaces 223d and 223e and the driven side friction surfaces 241a and 242a is adjusted by adjusting the pressing force that presses the driven side friction surfaces 241a and 242a against the drive side friction surfaces 223d and 223e. You can increase or decrease the power. Therefore, it is possible to easily adjust the limiter operating torque TL. For example, in the present embodiment, the pressing force for pressing the driven side friction surfaces 241a and 242a against the drive side friction surfaces 223d and 223e is determined according to the amount of elastic deformation of the disc spring 244, so adjustment of the amount of elastic deformation It is possible to easily adjust the operating torque TL.

  Further, according to the present embodiment, when the transmission torque Tr instantaneously increases at time t1 in FIG. 3, the transmission torque Tr is generated due to the compressor 16 compressing the refrigerant in the liquid phase. It is a momentary increase. Therefore, since the limiter operating torque TL is set based on the transfer torque Tr in the rare case where the compressor 16 compresses the liquid phase refrigerant, the frequency of occurrence of slippage in the torque limiter 24 is suppressed low. , It is possible to lower the limiter operating torque TL.

  Further, according to the present embodiment, when the transmission torque Tr instantaneously increases at time t2 in FIG. 3, the transmission torque Tr instantaneously becomes large due to the resonance of the power transmission system 19 (see FIG. 1). It is the case. Therefore, since the limiter operating torque TL is set based on the transmission torque Tr in the rare case of occurrence of resonance of the power transmission system 19, the limiter operating torque is suppressed while the frequency of occurrence of slippage in the torque limiter 24 is suppressed low. It is possible to lower the TL.

Second Embodiment
Next, a second embodiment will be described. In the present embodiment, points different from the first embodiment described above will be mainly described. In addition, the same or equivalent parts as those of the above-described embodiment will be described by omitting or simplifying them. The same applies to the description of the embodiments described later.

  As shown in FIG. 5, in addition to the torque limiter 24, the power transmission device 10 of the present embodiment includes an electromagnetic clutch 30 as a main configuration. The inner hub 248 of the present embodiment is not always connected non-rotatably to the rotation shaft 161 of the compressor 16 and rotates relative to the rotation shaft 161 if slippage occurs in the torque limiter 24. . The present embodiment is different from the first embodiment in these points. Further, the structure of the torque limiter 24 is also different from that of the first embodiment.

  The electromagnetic clutch 30 includes a pulley 20 as a clutch rotor, a stator 32 annularly formed around a compressor axis CL, an electromagnetic coil 33 accommodated in the stator 32, and an armature 34 integrally rotating with the inner hub 248. Have. The electromagnetic clutch 30 connects or disconnects the pulley 20 and the armature 34 to interrupt power transmission from the engine 12 to the compressor 16. FIG. 5 shows the pulley 20 and the armature 34 separated from each other. The same applies to later-described drawings for displaying the electromagnetic clutch 30 unless otherwise specified.

  The pulley 20 has an outer cylindrical portion 201, an inner cylindrical portion 202 and an end surface portion 203. The outer cylindrical portion 201 and the inner cylindrical portion 202 have a cylindrical shape extending in the compressor axial direction DRa, and the inner cylindrical portion 202 is disposed on the inner peripheral side of the outer cylindrical portion 201. The end surface portion 203 has a disk shape extending in the compressor radial direction DRr so as to connect the end portions on one side of the outer cylindrical portion 201 and the inner cylindrical portion 202 in the compressor axial direction DRa.

  The drive belt 18 is wound around the outer cylindrical portion 201 of the pulley 20, and the bearing 26 is fitted on the inner peripheral side of the inner cylindrical portion 202 of the pulley 20.

  The stator 32 and the armature 34 are made of a magnetic material such as iron. The stator 32 is a non-rotating member, and is disposed on the other side of the end face 203 of the pulley 20 in the compressor axial direction DRa. The stator 32 forms a slight gap so as not to interfere with the pulley 20.

  The armature 34 is a disk-like member having a through hole extending in the compressor radial direction DRr and penetrating the front and back thereof in the axial direction DRa in the central portion. The armature 34 is disposed on one side of the end surface 203 of the pulley 20 in the compressor axial direction DRa.

  The damper 22 of the present embodiment has an outer fitting 221 and an elastic member 222, and has an outer peripheral portion 248a of an inner hub 248 in place of the inner fitting 223 of the first embodiment. The elastic member 222 is joined to the outer peripheral portion 248 a of the inner hub 248 at the inner side in the radial direction.

  Further, the outer fitting 221 of the present embodiment is fixed to the armature 34 by caulking or the like. Therefore, movement of the armature 34 in the compressor axial direction DRa is permitted by deformation of the elastic member 222 of the damper 22. Then, the inner hub 248 rotates integrally with the damper 22 and the armature 34 around the compressor axis CL.

  Further, when the electromagnetic coil 33 is energized, the armature 34 is attracted to the end face 203 side of the pulley 20 by the magnetic force of the electromagnetic coil 33, and the armature 34 is brought into close contact with the end face 203. This enables power transmission from the pulley 20 to the inner hub 248.

  On the other hand, when the energization of the electromagnetic coil 33 is cut off, that is, when the electromagnetic coil 33 is not energized, the above-described magnetic force is not generated. Therefore, the armature 34 is separated from the end face 203 of the pulley 20 by the elastic force of the elastic member 222 of the damper 22. Thus, the power transmission path from the pulley 20 to the inner hub 248 is shut off, and the power transmission from the engine 12 to the compressor 16 is shut off.

  The torque limiter 24 of the present embodiment has a plurality of sliders 246, leaf spring members 247 provided for each of the sliders 246, an inner hub 248, and an inner hub support portion 164. In the torque limiter 24, the slider 246, the plate spring member 247, and the inner hub 248 form a drive unit 24 a that rotates with the pulley 20 when the electromagnetic coil 33 is energized. Further, the inner hub support portion 164 is a driven portion 24 b that rotates with the rotation shaft 161 of the compressor 16.

  The inner hub 248 has an outer peripheral portion 248 a that constitutes the outer peripheral portion of the inner hub 248.

  Further, as shown in FIGS. 5 to 7, a hub through hole 248 b which penetrates the inner hub 248 in the compressor axial direction DRa is formed on the inner peripheral portion of the inner hub 248. Further, a pair of slider insertion holes 248c which are recessed outward from the circumferential surface of the hub through hole 248b in the compressor radial direction DRr are formed. The pair of slider insertion holes 248 c are arranged at a pitch of 180 ° with the compressor axial center CL as a center, and thus open so as to face each other.

  The inner hub support portion 164 is also a part of the rotation shaft 161 of the compressor 16 and includes the tip portion of the rotation shaft 161 and is inserted into the hub through hole 248 b to support the inner hub 248. The inner hub support portion 164 has a recessed portion 164a formed in an annular shape around the compressor axis CL at the outer peripheral portion of the inner hub support portion 164 so as to be recessed inward in the compressor radial direction DRr. The recess 164a has a recess bottom surface 164b that forms the bottom of the recess 164a, and the recess bottom surface 164b faces the outside in the compressor radial direction DRr.

  The slider 246 is inserted into the slider insertion hole 248c. As a result, the slider 246 is restrained in the circumferential direction and axial direction DRa of the rotary shaft 161 with respect to the inner hub 248, but can slide in the radial direction DRr of the rotary shaft 161 with respect to the inner hub 248 ing.

  Further, the slider 246 has a slider inner peripheral portion 246a at an inner end in the compressor radial direction DRr. The slider inner peripheral portion 246a has a slider inner peripheral surface 246b facing inward in the compressor radial direction DRr. In addition, the slider inner circumferential portion 246a is a fitting portion that is fitted into the recess 164a of the rotating shaft 161. Therefore, the concave portion 164a restricts the slider inner peripheral portion 246a in the compressor axial direction DRa while allowing the slider inner peripheral portion 246a as the insertion portion to rotate around the compressor axis CL.

  Further, a plate spring member 247 is provided between the bottom surface 248 d of the slider insertion hole 248 c and the slider 246, and the plate spring member 247 is configured such that the slider 246 is on the inner side in the compressor radial direction DRr. It is biased to. Therefore, the plate spring member 247 functions as a pressing member for pressing the recess bottom surface 164b of the inner hub support portion 164 and the slider inner peripheral surface 246b to each other. Then, due to the biasing force of the plate spring member 247, the slider inner circumferential surface 246b and the concave bottom surface 164b of the inner hub support portion 164 face each other and are in frictional contact.

  That is, the slider inner circumferential surface 246b functions as a drive-side friction surface, and the concave bottom surface 164b of the inner hub support portion 164 functions as a driven-side friction surface pressed against the drive-side friction surface. The torque limiter 24 transmits power by the friction between the slider inner circumferential surface 246 b and the concave bottom surface 164 b of the inner hub support portion 164.

  Therefore, the torque limiter 24 of the present embodiment is also a self-restoration type torque limiter, similarly to the torque limiter 24 of the first embodiment. When the electromagnetic coil 33 is energized, the power of the engine 12 in the power transmission device 10 is transmitted from the drive belt 18 to the pulley 20, the armature 34, the damper 22, the inner hub 248, the slider 246, and the rotation shaft 161 of the compressor 16. It is transmitted in the order of Further, when the torque limiter 24 slips, power transmission is limited between the slider 246 and the inner hub support portion 164 of the rotation shaft 161.

  Also in the present embodiment, the magnitude of the limiter operating torque TL is the same as that of the first embodiment. That is, also in the present embodiment, when the transmission torque Tr instantaneously increases while the rotatable state of the rotation shaft 161 of the compressor 16 is maintained, slippage occurs in the torque limiter 24.

  Further, as described above, the slider inner circumferential portion 246 a is fitted into the recess 164 a of the inner hub support portion 164. Therefore, the recess 164a forms a step that prevents the slider 246 from moving in the compressor axial direction DRa.

  The concave portion 164a and the slider inner circumferential portion 246a function as a positional deviation prevention portion that prevents positional deviation between the inner hub 248 and the inner hub support portion 164 in the compressor axial direction DRa. That is, in the displacement prevention portion consisting of the concave portion 164a and the slider inner circumferential portion 246a, the inner hub 248 holds the inner hub support portion 164 by the concave portion 164a restraining the slider inner circumferential portion 246a in the compressor axial direction DRa. On the other hand, displacement in the compressor axial direction DRa is prevented. Specifically, when the slider inner circumferential surface 246 b slides against the concave bottom surface 164 b of the inner hub support portion 164, the inner hub 248 is in the compressor axial direction DRa with respect to the inner hub support portion 164. Prevent it from shifting. Recesses 164a restraining the slider inner circumferential portion 246a in the compressor axial direction DRa means that the recesses 164a and the slider inner circumferential portion 246a can not move relative to each other in the compressor axial direction DRa. That's what it means.

  Even when the slider inner circumferential surface 246 b does not slide with respect to the recess bottom surface 164 b of the inner hub support portion 164, the inner hub 248 is the inner hub support portion 164 by the slider inner circumferential portion 246 a and the recess portion 164 a. On the other hand, displacement in the compressor axial direction DRa is prevented. However, if the slider inner peripheral surface 246b and the recess bottom surface 164b do not slide, the recess 164a of the inner hub support portion 164 and the slider inner peripheral portion 246a of the slider 246 originally serve as a position gap prevention portion It does not have to work.

  The present embodiment is the same as the first embodiment except for the above description. And in this embodiment, the effect show | played from the structure common to above-mentioned 1st Embodiment can be acquired similarly to 1st Embodiment.

  Further, according to the present embodiment, as shown in FIGS. 5 and 7, the recess 164 a of the inner hub support portion 164 and the slider inner peripheral portion 246 a of the slider 246 function as the above-mentioned positional deviation prevention portion. . Then, when the slider inner circumferential surface 246 b slides against the recessed portion bottom surface 164 b of the inner hub support portion 164, the position shift prevention portion shifts the inner hub 248 with respect to the inner hub support portion 164 in the compressor axial direction DRa. To prevent. Therefore, it is possible to prevent the inner hub 248 from falling off the inner hub support 164 due to the positional deviation between the inner hub support 164 and the inner hub 248 in the compressor axial direction DRa.

  Further, according to the present embodiment, the slider inner circumferential portion 246 a is a fitting portion that is fitted into the recess 164 a of the inner hub support portion 164. The position shift prevention portion consisting of the concave portion 164a and the slider inner circumferential portion 246a has the inner hub 248 as the inner hub supporting portion by the concave portion 164a restraining the slider inner circumferential portion 246a in the compressor axial direction DRa. With respect to H.164, displacement in the compressor axial direction DRa is prevented. Accordingly, it is possible to prevent the positional deviation between the inner hub 248 and the inner hub support portion 164 in the compressor axial direction DRa with a simple configuration.

Third Embodiment
Next, a third embodiment will be described. In the present embodiment, differences from the above-described second embodiment will be mainly described.

  As shown in FIG. 8, the power transmission apparatus 10 according to the present embodiment includes an electromagnetic clutch 30 as a main component in addition to the torque limiter 24 as in the second embodiment. However, in the present embodiment, the torque limiter 24 has a tolerance ring 249, and power transmission is performed using the biasing force of the tolerance ring 249. The present embodiment is different from the second embodiment in this point.

  As shown in FIGS. 8 and 9, the inner hub 248 of the present embodiment has an inner circumferential portion 248e constituting an inner circumferential portion of the inner hub 248 in addition to the outer circumferential portion 248a to which the elastic member 222 of the damper 22 is joined. doing. The inner circumferential portion 248 e has a cylindrical shape extending in the compressor axial direction DRa, and a hub through hole 248 b is formed inside the inner circumferential portion 248 e. The inner hub support portion 164 of the rotating shaft 161 is inserted through the hub through hole 248b as in the second embodiment.

  Further, the inner circumferential portion 248 e has an inner hub inner circumferential surface 248 f which is formed on the inner side of the inner circumferential portion 248 e and contacts the tolerance ring 249. Further, the inner circumferential portion 248 e has an inner circumferential convex portion 248 g disposed at one end of the compressor axial direction DRa. The inner circumferential convex portion 248g is disposed on one side of the inner hub inner circumferential surface 248f in the compressor axial direction DRa, and protrudes inward with respect to the inner hub inner circumferential surface 248f in the compressor radial direction DRr.

  The inner hub support portion 164 of the rotating shaft 161 has a recess 164a as in the second embodiment. However, the tolerance ring 249 is fitted in the recess 164a.

  The torque limiter 24 according to the present embodiment includes the shaft tip plate 25, the inner hub 248 and the inner hub support portion 164 in addition to the tolerance ring 249 described above.

  The shaft tip plate 25 has a plate shape whose thickness direction is the compressor axial direction DRa, and is fixed by a bolt 252 to the tip surface 164c of the rotation shaft 161 of the compressor 16, ie, the tip surface 164c of the inner hub support portion 164. . The shaft end plate 25 is formed to project radially outward of the end surface 164 c of the rotating shaft 161. That is, the shaft end plate 25 has a flange portion 251 located radially outward of the front end surface 164 c of the rotating shaft 161. The axial tip plate 25 is used when press-fitting the inner hub 248 into the inner hub support portion 164 around which the tolerance ring 249 is wound.

  As shown in FIGS. 8 and 10, the tolerance ring 249 is a ring member extending annularly around the compressor axis CL, and is formed in a thin plate shape with the compressor radial direction DRr in the thickness direction. The tolerance ring 249 is a leaf spring member that exerts an urging force in the compressor radial direction DRr that repels elastic deformation whose thickness is compressed.

  Further, the tolerance ring 249 is not a completely closed annular shape, but has one circumferential end 249a and the other circumferential end 249b, and an empty space between the one circumferential end 249a and the other circumferential end 249b. An area 249c is formed.

  Specifically, the tolerance ring 249 has a band-like ring base 249 d extending in the circumferential direction of the rotation shaft 161 and a plurality of ring projections 249 e protruding outward from the ring base 249 d in the compressor radial direction DRr. . The plurality of ring projections 249 e each have a shape extending in the compressor axial direction DRa. Further, the plurality of ring protrusions 249 e are spaced apart from each other in the circumferential direction about the compressor axis CL. The plurality of ring projections 249 e are configured as elastic portions that can be elastically compressed in the thickness direction of the tolerance ring 249, that is, the compressor radial direction DRr. In FIG. 10, the back side shape of the ring protrusion 249e appearing on the inner side in the radial direction of the tolerance ring 249 is not shown.

  As shown in FIGS. 8 and 9, this tolerance ring 249 is disposed between the recess bottom surface 164b of the inner hub support portion 164 and the inner hub inner peripheral surface 248f. The tolerance ring 249 is press-fitted between the recess bottom surface 164b and the inner hub inner circumferential surface 248f. Specifically, the tolerance ring 249 is sandwiched between the concave bottom surface 164b and the inner hub inner circumferential surface 248f in the compressor radial direction DRr, whereby the plurality of ring projections 249e are respectively compressed and deformed in the compressor radial direction DRr. It is done.

  Therefore, the tolerance ring 249 functions as a pressing member that exerts a pressing force due to the compressive deformation of the ring protrusion 249e. That is, as shown in FIGS. 8 and 9, the tolerance ring 249 presses the tip end surface 249f of the ring protrusion 249e and the inner hub inner circumferential surface 248f opposite to the tip end surface 249f in the compressor radial direction DRr. ing. At the same time, the tolerance ring 249 presses the inner circumferential surface 249g of the ring base 249d and the concave bottom surface 164b of the inner hub support 164 opposite to the inner circumferential surface 249g in the compressor radial direction DRr.

  Therefore, the torque limiter 24 is configured such that the friction between the tip end surface 249f of the ring protrusion 249e and the inner hub inner peripheral surface 248f and the friction between the inner peripheral surface 249g of the ring base 249d and the recessed bottom surface 164b of the inner hub support portion 164. And transmit power. When the electromagnetic coil 33 is energized, the power of the engine 12 in the power transmission device 10 is transmitted from the drive belt 18 to the pulley 20, the armature 34, the damper 22, the inner hub 248, the tolerance ring 249, and the rotation shaft 161 of the compressor 16. It is transmitted in order. Also, when slippage occurs in the torque limiter 24, power transmission is performed between the inner hub support portion 164 and the tolerance ring 249 of the rotation shaft 161 or between the inner peripheral portion 248e of the inner hub 248 and the tolerance ring 249. Is limited.

  In addition, since the tip end surface 249f of the ring protrusion 249e is opposed to the inner hub inner circumferential surface 248f, it is a surface facing the outside in the compressor radial direction DRr. On the other hand, since the inner circumferential surface 249g of the ring base 249d faces the concave bottom surface 164b, the inner circumferential surface 249g faces inward in the compressor radial direction DRr.

  Also in this embodiment, the magnitude of the limiter operating torque TL is the same as in the second embodiment. That is, also in the present embodiment, when the transmission torque Tr instantaneously increases while the rotatable state of the rotation shaft 161 of the compressor 16 is maintained, slippage occurs in the torque limiter 24.

  Here, the tolerance ring 249 is in frictional contact with both the inner hub 248 and the inner hub support portion 164 of the rotating shaft 161. Therefore, when the torque limiter 24 slips, the tolerance ring 249 slides on one of the inner hub 248 and the inner hub support portion 164 and does not rotate relative to the other. That is, in the first case where the tolerance ring 249 is fixed relative to the inner hub support 164 while fixed relative to the inner hub 248, the tolerance ring 249 rotates relative to the inner hub 248 while fixed relative to the inner hub support 164. There is also a second case.

  For example, among the first and second cases described above, it is assumed that the tolerance ring 249 is fixed to the inner hub 248 and rotates relative to the inner hub support portion 164. In this case, of the torque limiter 24, the inner hub 248 and the tolerance ring 249 become a drive portion 24a that rotates with the pulley 20 when the electromagnetic coil 33 is energized. On the other hand, the shaft end plate 25 and the inner hub support portion 164 become a driven portion 24 b that rotates with the rotation shaft 161 of the compressor 16. The inner circumferential surface 249g of the ring base 249d is the drive-side friction surface formed on the drive portion 24a, and the concave bottom surface 164b of the inner hub support portion 164 is on the driven-side friction surface formed in the driven portion 24b. Become.

  Further, the ring base 249 d constitutes a part of the drive part 24 a and becomes an insertion part which is fitted into the recess 164 a of the inner hub support part 164. The ring base 249 d and the recess 164 a serving as the insertion portion function as a positional deviation prevention portion that prevents positional deviation between the drive portion 24 a and the driven portion 24 b in the compressor axial direction DRa.

  Conversely, it is assumed that the tolerance ring 249 rotates relative to the inner hub 248 while being fixed to the inner hub support portion 164 of the rotation shaft 161. In that case, the inner hub 248 of the torque limiter 24 becomes a drive portion 24 a that rotates with the pulley 20 when the electromagnetic coil 33 is energized. On the other hand, the shaft tip plate 25, the inner hub support portion 164 and the tolerance ring 249 become a driven portion 24 b that rotates with the rotation shaft 161 of the compressor 16. Then, the inner hub inner circumferential surface 248 f becomes the drive side friction surface, and the tip end surface 249 f of the ring protrusion 249 e becomes the driven side friction surface.

  Furthermore, a concave portion in which the one side protrusion forming portion 249 h of the ring protrusion portion 249 e formed on one side in the compressor axial direction DRa and the flange portion 251 of the shaft end plate 25 constitute a part of the driven portion 24 b. become. The recess is recessed in the compressor radial direction DRr. Further, the inner circumferential convex portion 248g of the inner hub 248 is a fitting portion which is fitted into the concave portion formed by the one side protrusion forming portion 249h and the flange portion 251. Therefore, the concave portion restrains the inner peripheral convex portion 248g in the compressor axial direction DRa while permitting the inner peripheral convex portion 248g as the insertion portion to rotate around the compressor axis CL. The concave portion and the inner peripheral convex portion 248g as the insertion portion function as the above-described positional deviation prevention portion that prevents positional deviation between the drive portion 24a and the driven portion 24b in the compressor axial direction DRa.

  The present embodiment is the same as the second embodiment except for the above description. And in this embodiment, the effect show | played from the structure common to above-mentioned 2nd Embodiment can be acquired similarly to 2nd Embodiment.

  Further, according to the present embodiment, when the tolerance ring 249 rotates relative to the inner hub support portion 164 while being fixed to the inner hub 248, the drive portion 24a of the torque limiter 24 functions as a pressing member. Have. The inner circumferential surface 249 g of the ring base 249 d of the tolerance ring 249 is the drive-side friction surface. Therefore, it is not necessary to provide a member having the drive side friction surface separately from the tolerance ring 249. Therefore, it is easy to reduce the number of parts of the torque limiter 24 and to miniaturize the torque limiter 24.

  On the other hand, when the tolerance ring 249 rotates relative to the inner hub 248 while being fixed to the inner hub support portion 164 of the rotating shaft 161, the driven portion 24 b of the torque limiter 24 has the tolerance ring 249. The tip end surface 249f of the ring protrusion 249e of the tolerance ring 249 is the driven friction surface. Therefore, it is not necessary to provide a member having the driven side friction surface separately from the tolerance ring 249. Therefore, it is easy to reduce the number of parts of the torque limiter 24 and to miniaturize the torque limiter 24.

Fourth Embodiment
Next, a fourth embodiment will be described. In the present embodiment, points different from the first embodiment described above will be mainly described.

  As shown in FIG. 11, in the power transmission device 10 of the present embodiment, the torque limiter 24 has the magnetorheological fluid Fm, and like the clutch mechanism using the magnetorheological fluid Fm, the viscosity of the magnetorheological fluid Fm Perform power transmission. The torque limiter 24 of the present embodiment also has the same function as the function of the electromagnetic clutch 30 of the second embodiment for interrupting the power transmission from the pulley 20 to the compressor 16. The present embodiment is different from the first embodiment in these points.

  Specifically, as shown in FIGS. 11 and 12, the torque limiter 24 of the present embodiment has a stator 32, an electromagnetic coil 33, and an end face 203 which is a part of the pulley 20. The stator 32 and the electromagnetic coil 33 are the same as those in the second embodiment. Further, the end face portion 203 is the same as that of the second embodiment except that a nonmagnetic ring member 203a and a sealing material 204 which will be described later are provided. In addition, the armature 34 and the damper 22 of 2nd Embodiment are not provided in the power transmission device 10 of this embodiment.

  Further, although the torque limiter 24 of the present embodiment has the inner hub 243, unlike the first embodiment, it has the first friction member 241, the second friction member 242, the disc spring 244 and the retaining ring 245. It is not The inner hub 243 has a shaft portion 243 a and a collar portion 243 d protruding like a collar outward from the shaft portion 243 a in the radial direction. The shaft portion 243 a of the inner hub 243 is non-rotatably connected to the rotation shaft 161 as in the first embodiment.

  Also, the torque limiter 24 of the present embodiment has a cover 28. The cover 28 is arranged to cover the inner hub 243 from one side of the compressor axial direction DRa. Further, the cover 28 has an end surface adjacent portion 282 aligned with the end surface portion 203 of the pulley 20 at an interval in the compressor axial direction DRa. The outer peripheral portion of the end surface adjacent portion 282 is fixed to the outer cylindrical portion 201 of the pulley 20 by a plurality of bolts 281.

  The flange portion 243 d of the inner hub 243 is disposed between the end surface adjacent portion 282 of the cover 28 and the end surface portion 203 of the pulley 20 in the compressor axial direction DRa. Then, the flange portion 243 d forms a gap Ca between the end surface portion 203 and the compressor shaft direction DRa, and also forms a gap Cb between the end surface adjacent portion 282 and the compressor shaft direction DRa. There is. Therefore, the flange portion 243 d is not in direct contact with the end surface portion 203 or the end surface adjacent portion 282.

  The gap Ca between the ridge portion 243 d and the end surface portion 203 and the gap Cb between the ridge portion 243 d and the end surface adjacent portion 282 are filled with the magnetorheological fluid Fm of the torque limiter 24. However, an annular seal member 204 is provided at the radially inner end of the end face portion 203 of the pulley 20, and the seal member 204 is in contact with the flange portion 243 d of the inner hub 243. Accordingly, the magneto-rheological fluid Fm, which fills the gap Ca between the flange portion 243 d and the end face portion 203, is prevented by the seal member 204 from flowing radially inward of the seal member 204.

  The end face portion 203 of the pulley 20 has a nonmagnetic ring member 203a extending in the circumferential direction of the rotating shaft 161, and the nonmagnetic ring member 203a is made of a nonmagnetic material. That is, the portion of the end face 203 excluding the nonmagnetic ring member 203a is a magnetic material constituting portion made of a magnetic material.

  The nonmagnetic ring member 203 a is disposed radially outside the seal member 204 in the end face portion 203. The periphery of the nonmagnetic ring member 203a is airtight so that the magnetorheological fluid Fm does not leak from the periphery of the nonmagnetic ring member 203a.

  The stator 32 and the electromagnetic coil 33 function as a magnetic field application unit that applies a magnetic field to the magnetorheological fluid Fm. When the electromagnetic coil 33 is energized, a magnetic circuit Mc shown by an alternate long and short dash line in FIG. 12 is formed. The flow of the magnetic flux of the magnetic circuit Mc is determined by the gap Ca between the ridge portion 243 d of the inner hub 243 and the end surface portion 203 of the pulley 20 and between the ridge portion 243 d and the end surface adjacent portion 282 of the cover 28. In each of the gaps Cb, the magnetorheological fluid Fm is crossed.

  From such a configuration, as shown in FIGS. 11 and 12, the end face portion 203 of the pulley 20 and the cover 28 constitute a drive portion 24 a of the torque limiter 24 that rotates with the pulley 20. The inner hub 243 is a driven portion 24 b of the torque limiter 24 that rotates with the rotation shaft 161 of the compressor 16.

  In addition, when the electromagnetic coil 33 is energized, a magnetic field is applied to the magnetorheological fluid Fm, and the viscosity of the magnetorheological fluid Fm is increased by the application of the magnetic field. For example, since the magnetorheological fluid Fm to which the magnetic field is applied becomes substantially solid, the inner hub 243 rotates integrally or substantially integrally with the pulley 20, whereby the power from the pulley 20 to the inner hub 243 is obtained. Transmission becomes possible. That is, the torque limiter 24 transmits power from the pulley 20 to the inner hub 243 via the magnetorheological fluid Fm to which a magnetic field is applied by the stator 32 and the electromagnetic coil 33.

  Specifically, when the electromagnetic coil 33 is energized, the power of the engine 12 in the power transmission device 10 is from the drive belt 18 to the pulley 20 and the cover 28, the magnetorheological fluid Fm, the inner hub 243, and the rotation shaft 161 of the compressor 16. It is transmitted in order.

  On the other hand, when the energization of the electromagnetic coil 33 is cut off, that is, when the electromagnetic coil 33 is not energized, the above-described magnetic field is not applied. That is, the magnetic circuit Mc of FIG. 12 is not configured. Therefore, the pulley 20 can freely rotate relative to the inner hub 243, whereby the power transmission path from the pulley 20 to the inner hub 243 is shut off, and the power transmission from the engine 12 to the compressor 16 is shut off.

  Further, the limiter operating torque TL of the present embodiment can be adjusted in accordance with the strength of the magnetic field generated by the applied current applied to the electromagnetic coil 33, the characteristics of the magnetorheological fluid Fm, etc. The magnitude of the torque TL is the same as in the first embodiment. That is, when the transmission torque Tr instantaneously increases while the rotatable state of the rotary shaft 161 of the compressor 16 is maintained when the electromagnetic coil 33 is energized, slippage occurs in the torque limiter 24. The slip of the torque limiter 24 in the present embodiment means that the end face portion 203 of the pulley 20 and the cover 28 rotate relative to the inner hub 243 in the torque limiter 24. At the time of the occurrence of the slip, shear occurs at any point of the magnetorheological fluid Fm such as the interface of the magnetorheological fluid Fm.

  The present embodiment is the same as the first embodiment except for the above description. And in this embodiment, the effect show | played from the structure common to above-mentioned 1st Embodiment can be acquired similarly to 1st Embodiment.

  Further, according to the present embodiment, the torque limiter 24 includes the end face portion 203 of the pulley 20 and the cover 28 as the drive portion 24 a and the inner hub 243 as the driven portion 24 b. The torque limiter 24 further includes a magnetorheological fluid Fm that fills the gaps Ca and Cb between the drive portion 24a and the driven portion 24b, and the stator 32 and the electromagnetic coil 33 that apply a magnetic field to the magnetorheological fluid Fm. Have. The torque limiter 24 also transmits power from the drive unit 24a to the driven unit 24b via the magnetorheological fluid Fm to which a magnetic field is applied. In addition, when the transmission torque Tr becomes equal to or higher than the limiter operating torque TL when the electromagnetic coil 33 is energized, slippage occurs in the torque limiter 24, and the slip of the torque limiter 24 means that the drive part 24 a is driven by the driven part 24 b. It is to rotate relative to it. Therefore, it is possible to provide the torque limiter 24 with a function as an electromagnetic clutch using the magnetorheological fluid Fm without providing a clutch separately from the torque limiter 24.

(Other embodiments)
(1) In the second embodiment described above, as shown in FIGS. 5 and 7, the slider inner circumferential portion 246a of the slider 246 inserted into the slider insertion hole 248c of the inner hub 248 is the inner hub support portion. Although it is an insertion part inserted in the recessed part 164a of 164, this is an example. For example, conversely, a recess may be formed in the inner hub 248, and a fitting portion fitted in the recess may be formed in the inner hub support portion 164, and the recess and the fitting portion may function as a positional deviation prevention unit.

  (2) As shown in FIG. 11 in the fourth embodiment described above, the torque limiter 24 performs power transmission by the viscosity of the magnetorheological fluid Fm, but this is an example. For example, the torque limiter 24 may have magnetic powder instead of the magnetorheological fluid Fm, and power transmission may be performed by the magnetic powder.

  (3) In each of the above-described embodiments, as shown in FIG. 3, when the transmission torque Tr instantaneously increases due to the compressor 16 compressing the liquid-phase refrigerant, slippage occurs in the torque limiter 24. Occur. In addition, slippage occurs in the torque limiter 24 also when the transmission torque Tr momentarily increases due to the resonance of the power transmission system 19. However, this is an example. For example, in one of the compression of the liquid phase refrigerant and the resonance of the power transmission system 19, slippage occurs in the torque limiter 24, and in the other case, slippage does not occur. There is no problem even if the limiter operating torque TL is set. The maximum value of the transfer torque Tr in the other case is smaller than the limiter operating torque TL.

  (4) In the second and third embodiments described above, in the torque limiter 24, the drive portion 24a is in the compressor axial direction with respect to the driven portion 24b by the recessed portion and the inserted portion inserted into the recessed portion. Although it prevents shifting to DRa, this is an example. For example, the displacement prevention portion uses a thrust bearing provided so as not to move relative to one of the drive portion 24a and the driven portion 24b in the compressor axial direction DRa, and the drive portion 24a and the driven portion 24b For one of the two, the other may be prevented from shifting in the compressor axial direction DRa.

  (5) In addition, this invention can be variously deformed and implemented, without being limited to the above-mentioned embodiment. Further, in each of the above-described embodiments, it is needless to say that the elements constituting the embodiment are not necessarily essential except when clearly indicated as being essential and when it is considered to be obviously essential in principle. Yes.

  Further, in the above embodiments, when numerical values such as the number, numerical value, amount, range, etc. of constituent elements of the embodiment are mentioned, it is clearly indicated that they are particularly essential and clearly limited to a specific number in principle. It is not limited to the specific number except when it is done. Further, in the above embodiments, when referring to materials, shapes, positional relationships, etc. of constituent elements etc., unless specifically stated otherwise or in principle when limited to a specific material, shape, positional relationship, etc., etc. It is not limited to the material, the shape, the positional relationship, etc.

(Summary)
According to the first aspect of the present invention shown in part or all of the above embodiments, when the transmission torque is momentarily increased while maintaining the rotatable state of the driven body, the torque limiter is slipped. Occurs. Then, if it is settled that the transmission torque has increased momentarily, the slip of the torque limiter is eliminated.

  Further, according to the second aspect, the torque limiter is formed with a drive portion formed on the drive side friction surface and rotating with the pulley, and a driven side friction surface pressed against the drive side friction surface is formed to rotate together with the driven body. And a driven part. The torque limiters transmit power by the friction between their drive-side friction surface and the driven-side friction surface. The slippage of the torque limiter means that the drive-side friction surface slides against the driven-side friction surface, and the drive portion rotates relative to the driven portion. Therefore, the friction force between the drive-side friction surface and the driven-side friction surface increases or decreases by adjusting the pressing force that presses the driven-side friction surface against the drive-side friction surface, thereby causing slippage in the torque limiter. It is possible to easily adjust the torque threshold of the transfer torque.

  According to the third aspect, the drive portion and the driven portion rotate around a predetermined axis, and the drive-side friction surface and the driven-side friction surface face each other in the axial direction of the predetermined axis. ing.

  Further, according to the fourth aspect, the drive portion and the driven portion rotate around a predetermined axis, and the drive-side friction surface and the driven-side friction surface face each other in the radial direction of the predetermined axis. ing.

  Further, according to the fifth aspect, the torque limiter has a displacement prevention portion, and the displacement portion prevents the drive portion from moving when the drive-side friction surface slides against the driven-side friction surface. It is prevented that the driven part deviates in the axial direction of the predetermined axial center. Therefore, it is possible to prevent the drive unit from falling off the driven unit due to the positional deviation between the driven unit and the drive unit in the axial direction.

  Further, according to the sixth aspect, the displacement prevention portion has a concave portion which is recessed in the radial direction and a fitting portion which is fitted into the concave portion, and one of the concave portion and the fitting portion is one of the driving portions. The other part of the recess and the fitting part constitutes a part of the driven part. The positional displacement preventing portion prevents the drive portion from being displaced in the axial direction with respect to the driven portion by the recessed portion axially restraining the insertion portion. Therefore, it is possible to prevent positional deviation between the driven portion and the driving portion in the axial direction with a simple configuration.

  Further, according to the seventh aspect, the drive unit has a pressing member for pressing the driven side friction surface and the drive side friction surface to each other, and the drive side friction surface is formed on the pressing member of the drive unit. ing. Therefore, it is easy to reduce the number of parts of the torque limiter and to miniaturize the torque limiter.

  Further, according to the eighth aspect, the driven portion has a pressing member for pressing the driven side friction surface and the driving side friction surface to each other, and the driven side friction surface is a pressing member of the driven portion. Is formed. Also in this case, as in the seventh aspect, the number of parts of the torque limiter can be reduced, and the torque limiter can be easily miniaturized.

  Further, according to the ninth aspect, the torque limiter includes a drive unit that rotates with the pulley, a driven unit that forms a gap between the drive unit and the drive unit, and a magnetorheological fluid that fills the gap. And a magnetic field application unit for applying a magnetic field to the magnetorheological fluid. The viscosity of the magnetorheological fluid is increased by applying a magnetic field. The torque limiter transmits power from the drive unit to the driven unit via the magnetorheological fluid to which the magnetic field is applied by the magnetic field application unit. Further, the slip of the torque limiter means that the drive portion rotates relative to the driven portion. Therefore, it is possible to equip the torque limiter with a function as an electromagnetic clutch using a magnetorheological fluid without providing a clutch separately from the torque limiter.

  Further, according to the tenth aspect, the driven body is a rotary shaft of a compressor that compresses the refrigerant. The case where the transmission torque is momentarily increased is a case where the transmission torque is momentarily increased due to the compression of the refrigerant in the liquid phase by the compressor. Therefore, since the torque threshold value of the torque limiter is set based on the transmission torque in the rare situation where the compressor compresses the liquid phase refrigerant, the frequency of occurrence of slippage in the torque limiter is suppressed low. It is possible to lower the torque threshold of the limiter.

  Further, according to the eleventh aspect, the drive belt, the pulley, and the torque limiter are included in the power transmission system for transmitting the power from the drive source generating the power to the driven body. The case where the transmission torque is momentarily increased is the case where the transmission torque is momentarily increased due to the resonance of the power transmission system. Therefore, since the torque threshold of the torque limiter is set based on the transmission torque in the rare case of occurrence of resonance of the power transmission system, the torque threshold of the torque limiter is suppressed while suppressing the frequency of occurrence of slippage in the torque limiter. It is possible to lower

  Further, according to the twelfth aspect, when the above-mentioned transmission torque is instantaneously increased, when the transmission torque is instantaneously increased due to the compression of the refrigerant in the liquid phase by the compressor. And when the transmission torque instantaneously increases due to the resonance of the power transmission system. Therefore, as described in the above tenth and eleventh aspects, it is possible to lower the torque threshold of the torque limiter while suppressing the frequency of occurrence of slippage in the torque limiter.

10 power transmission device 18 drive belt 20 pulley 24 torque limiter 161 rotating shaft (driven body)

Claims (12)

A power transmission device for transmitting power for rotating a driven body (161) from a drive belt (18) to the driven body, wherein
A pulley (20) around which the drive belt is wound and rotationally driven by the drive belt;
A torque which is provided in a power transmission path between the pulley and the driven body and which causes slip when the transmission torque (Tr) transmitted from the pulley to the driven body becomes equal to or greater than a predetermined torque threshold Equipped with a limiter (24),
When the transmission torque instantaneously increases while maintaining the rotatable state of the driven body, the slip occurs in the torque limiter,
The power transmission device, wherein the slip of the torque limiter is eliminated when the transmission torque is instantaneously increased. The torque limiter includes a drive portion (24a) formed with drive-side friction surfaces (223d, 223e, 246b, 249g, and 248f) and rotating with the pulley, and a driven-side friction surface pressed against the drive-side friction surface ( 241a, 242a, 164b, 249f) and includes a driven portion (24b) that rotates with the driven body, and the power is generated by the friction between the drive-side friction surface and the driven-side friction surface. Communicate
The power according to claim 1, wherein the slip of the torque limiter is that the drive-side friction surface slides against the driven-side friction surface, and the drive unit rotates relative to the driven unit. Transmission device. The drive unit and the driven unit rotate around a predetermined axis (CL),
The power transmission according to claim 2, wherein the drive side friction surface (223d, 223e) and the driven side friction surface (241a, 242a) face each other in the axial direction (DRa) of the predetermined axial center. apparatus. The drive unit and the driven unit rotate around a predetermined axis (CL),
The drive side friction surfaces (246b, 249g, 248f) and the driven side friction surfaces (164b, 249f) face each other in the radial direction (DRr) of the predetermined axial center. Power transmission. The torque limiter has position shift prevention units (164a, 246a, 249d, 164a, 249h, 251, 248g),
When the drive-side friction surface slides against the driven-side friction surface, the displacement prevention unit shifts the drive unit in the axial direction (DRa) of the predetermined axial center with respect to the driven unit. The power transmission device according to claim 4, which prevents that. The displacement prevention portion includes the radially recessed portion (164a, 249h, 251), and a fitting portion (246a, 249d, 248g) fitted in the recessed portion.
One of the concave portion and the fitting portion constitutes a part of the driving portion, and the other of the concave portion and the fitting portion constitutes a part of the driven portion.
The power according to claim 5, wherein the displacement prevention portion prevents the drive portion from being displaced in the axial direction with respect to the driven portion by the concave portion restraining the fitting portion in the axial direction. Transmission device. The drive unit includes a pressing member (249) for pressing the driven friction surface (164b) and the drive friction surface (249g) to each other.
The power transmission device according to any one of claims 4 to 6, wherein the drive-side friction surface is formed on the pressing member of the drive unit. The driven portion has a pressing member (249) for pressing the driven side friction surface (249f) and the drive side friction surface (248f) to each other,
The power transmission apparatus according to any one of claims 4 to 6, wherein the driven side friction surface is formed on the pressing member of the driven portion. The torque limiter includes a drive unit (24a) that rotates with the pulley, a driven unit (24b) that forms a gap (Ca, Cb) between the drive unit and the drive unit, and the gap And a magnetic field application unit (32, 33) for applying a magnetic field to the magnetorheological fluid,
The viscosity of the magnetorheological fluid is increased by applying a magnetic field,
The torque limiter transmits the power from the drive unit to the driven unit via the magnetorheological fluid to which a magnetic field is applied by the magnetic field application unit.
The power transmission apparatus according to claim 1, wherein the slip of the torque limiter is that the drive portion rotates relative to the driven portion. The driven body is a rotating shaft (161) of a compressor (16) that compresses a refrigerant,
10. The case where the transmission torque is increased momentarily is a case where the transmission torque is increased momentarily because the compressor compresses a liquid phase refrigerant. The power transmission device according to any one. The drive belt, the pulley, and the torque limiter are included in a power transmission system (19) for transmitting the power from the drive source (12) generating the power to the driven body.
The power transmission according to any one of claims 1 to 9, wherein the case where the transmission torque is momentarily increased is a case where the transmission torque is momentarily increased due to the resonance of the power transmission system. apparatus. The driven body is a rotating shaft (161) of a compressor (16) that compresses a refrigerant,
The drive belt, the pulley, and the torque limiter are included in a power transmission system (19) for transmitting the power from the drive source (12) generating the power to the driven body.
When the transmission torque is instantaneously increased, when the transmission torque is instantaneously increased due to the compression of the refrigerant in the liquid phase by the compressor, and the resonance of the power transmission system The power transmission apparatus according to any one of claims 1 to 9, wherein the transmission torque is momentarily increased by the.

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