JP5875393B2 - Dynamic damper device and lock-up device for fluid power transmission device - Google Patents

Description

  The present invention relates to a dynamic damper device, and more particularly, to a dynamic damper device disposed between a piston of a lockup device and a turbine hub of a fluid power transmission device. The present invention also relates to a lockup device, and more particularly to a lockup device for mechanically transmitting power from a front cover to a turbine hub of a fluid power transmission device.

  In a torque converter as a fluid power transmission device, a lockup device is provided to reduce fuel consumption. The lockup device is disposed between the turbine and the front cover, and mechanically connects the front cover and the turbine to directly transmit torque between the two.

  Generally, the lockup device has a piston and a damper mechanism. The piston is pressed against the front cover by the action of hydraulic pressure, and torque is transmitted from the front cover. The damper mechanism also includes an output-side member connected to the turbine and a plurality of torsion springs for elastically connecting the piston and the output-side member. The torque transmitted to the piston is transmitted to the output side member via a plurality of torsion springs, and further transmitted to the turbine.

  Patent Document 1 discloses a lockup device that suppresses engine rotation fluctuations by attaching an inertia member to an output-side member. In the lockup device disclosed in Patent Document 1, an inertia member is attached to an output member fixed to a turbine so as to be relatively rotatable. A torsion spring as an elastic member is provided between the output member and the inertia member.

  In the lock-up device disclosed in Patent Document 1, since the inertia member is connected to the output member via the torsion spring, the inertia member and the torsion spring function as a dynamic damper, thereby rotating the output side member (turbine). Speed fluctuation is attenuated.

JP 2009-293671 A

  In recent passenger cars, in order to improve fuel efficiency, it is required to set the rotational speed at which the front cover and the turbine are coupled (hereinafter referred to as “lock-up rotational speed”) to a lower rotational speed. However, in general, the engine speed fluctuation is large in the region where the engine speed is low. Therefore, if the lockup speed is set to a low speed, the output speed fluctuation becomes larger. Therefore, by using a lock-up device having an inertia member as shown in Patent Document 1, even if the lock-up rotation speed is about 1200 rpm, for example, rotation fluctuation can be suppressed.

  However, for example, when the specification is such that the rotational speed fluctuation on the output side is minimized near 1200 rpm, there is a problem that the rotational speed fluctuation becomes large near 1600 rpm. The characteristic of this rotational speed fluctuation, that is, at which rotational speed the rotational speed fluctuation is minimized and maximized is mainly due to the magnitude of the hysteresis torque generated between the output member and the inertia member. Yes.

  In the lock-up device disclosed in Patent Document 1, a hysteresis torque generating mechanism is provided, but it is not possible to suppress the rotational speed fluctuation on the output side in a wide rotational speed range. In the lockup device disclosed in Patent Document 1, a pair of plates are fixed to the turbine hub by rivets in order to restrict the movement of the dynamic damper device in the axial direction.

  An object of the present invention is to be able to suppress rotational fluctuation on the output side in a wide rotational speed range even when the lockup rotational speed is set to a low rotational speed, and to restrict axial movement with a compact configuration. Is to be able to do that.

  A dynamic damper device according to a first aspect of the present invention is a device disposed between a piston of a lockup device and a turbine hub of a fluid power transmission device, and includes a pair of annular plates, an annular hub flange, an inertia A member, an elastic member, and a hysteresis torque generating mechanism are provided. The pair of plates can be connected to a turbine hub while receiving torque from the piston. The annular hub flange is disposed between the pair of plates and is rotatable relative to the pair of plates. The inertia member is fixed to the hub flange. The elastic member elastically connects the pair of plates and the hub flange in the rotational direction. The hysteresis torque generating mechanism is disposed on the inner peripheral side of the hub flange between the pair of plates in the axial direction, and generates a variable hysteresis torque between the pair of plates and the hub flange. One of the pair of plates is sandwiched between the inner peripheral portion of the piston and the turbine hub, and movement in the axial direction is restricted.

  In this apparatus, torque is input to a pair of plates via a piston and output to a turbine hub to which the pair of plates are connected. A hub flange to which an inertia member is fixed via an elastic member is disposed between the pair of plates. This inertia member suppresses fluctuations in rotational speed.

  Here, the pair of plates and the hub flange rotate relative to each other, and a hysteresis torque generated by a hysteresis torque generating mechanism acts between them. Depending on the magnitude of this hysteresis torque, the characteristics of the rotational speed fluctuation on the output side change.

  Therefore, in the present invention, the hysteresis torque is changed depending on the rotational speed range so that the rotational speed fluctuation on the output side becomes small in a wide rotational speed range. Therefore, even when the lockup rotational speed is set to a low rotational speed, fluctuations in rotational speed can be suppressed in a wide rotational speed region.

  In addition, since one of the pair of plates is sandwiched between the piston and the turbine hub and the movement in the axial direction is restricted, this shaft can be configured with a simple configuration without requiring rivets or other members. The axial movement of the entire dynamic damper device including the plate whose movement in the direction is restricted can be restricted.

  A dynamic damper device according to a second invention is the device according to the first invention, wherein the hysteresis torque generating mechanism generates a first hysteresis torque in a low rotation speed range and a first hysteresis torque in a medium rotation speed range to a high rotation speed range. Larger second hysteresis torque is generated.

  When the hysteresis torque between the pair of plates and the hub flange is small, the output side rotational speed fluctuation is small in the low rotational speed range, and conversely, when it is large, the rotational speed fluctuation is small in the medium rotational speed range. Therefore, in the present invention, the first hysteresis torque is generated in the low rotation speed range, and the larger second hysteresis torque is generated in the medium rotation speed range to the high rotation speed range. Therefore, the rotational speed fluctuation on the output side can be suppressed in a wide rotational speed range.

  The dynamic damper device according to a third aspect of the present invention is the device of the first or second aspect, wherein the plate sandwiched between the inner peripheral portion of the piston and the turbine hub is in contact with the outer peripheral surface of the turbine. Positioning in the radial direction is made.

  Here, the entire apparatus can be positioned in the axial and radial directions with a single plate.

  A dynamic damper device according to a fourth invention is the dynamic damper device according to any one of the first to third inventions, wherein the hysteresis torque generating mechanism has a plurality of sliders that rotate together with a pair of plates and are movable in a radial direction. When the pair of plates has a predetermined number of revolutions or more, the slider moves radially outward by centrifugal force and contacts the inner peripheral surface of the hub flange.

  Here, hysteresis torque that varies depending on the number of rotations can be generated by using centrifugal force acting on the slider. For this reason, a hysteresis torque generating mechanism can be realized with a simple configuration.

  A dynamic damper device according to a fifth invention is the device according to the fourth invention, wherein the hysteresis torque generating mechanism further includes a pressing mechanism that presses the plurality of sliders against at least one of the pair of plates, and the portion pressed by the pressing mechanism is provided. The slider is pressed more strongly against the inner peripheral surface of the hub flange by lever action as a fulcrum.

  In order to generate a large hysteresis torque, it is necessary to increase the centrifugal force by increasing the slider. However, this requires a large occupied space. On the other hand, if the slider is made smaller for miniaturization, the centrifugal force acting on the slider is also reduced, and a large hysteresis torque cannot be generated.

  Therefore, in the present invention, a pressing mechanism for pressing the slider against at least one plate is further provided, and a large hysteresis can be generated even with a small slider by utilizing the lever principle.

  The dynamic damper device according to a sixth aspect of the present invention is the device of the fifth aspect, wherein the pressing mechanism has a contact portion and a support portion. The contact portion is formed on at least one of the pair of plates, and is arranged with a gap from the side surface in the rotation direction of the slider. The support portion supports the slider so as to be swingable in the rotational direction with respect to the turbine hub.

  In this apparatus, when the slider comes into contact with the hub flange by centrifugal force, the slider tries to rotate together with the hub flange, and thus swings around the support portion. Due to the swing of the slider, the side surface of the slider comes into contact with the contact portion of the plate.

  Here, the slider can be strongly pressed against at least one of the pair of plates with a simple mechanism, and a large hysteresis torque can be easily generated.

  A lockup device for a fluid power transmission device according to a seventh aspect of the invention is a device for mechanically transmitting power from a front cover to a turbine hub of the fluid power transmission device, a piston pressed against the front cover, The dynamic damper device according to any one of the first to sixth inventions, and an elastic member that elastically connects the piston and the dynamic damper device in the rotational direction.

  In the present invention as described above, the lock-up rotation speed can be set to a lower rotation speed, and the turbine rotation fluctuation can be suppressed in a wide rotation speed range. For this reason, low fuel consumption can be realized. In addition, the movement of the apparatus in the axial direction can be restricted with a compact configuration.

The cross-sectional block diagram of the torque converter provided with the lockup apparatus by one Embodiment of this invention. The cross-sectional block diagram of the said lockup apparatus. Sectional drawing of a 1st plate. The IV direction arrow partial view of FIG. The enlarged view of the convex part of a 1st plate. It is sectional drawing of a 2nd plate, and the VI-VI sectional view taken on the line of FIG. FIG. 9 is another cross-sectional view of the second plate, taken along the line VII-VII in FIG. 8. The figure which looked at FIG. 6 from the XIII direction. The figure which looked at FIG. 7 from IX direction. Sectional drawing of a hub flange and an inertia member. The partial view which looked at FIG. 10 from the XI direction. The schematic diagram of a hysteresis torque generation mechanism. The fragmentary sectional view of a hysteresis torque generating mechanism. FIG. 3 is a characteristic diagram of engine speed and rotational speed fluctuation. The operation principle figure for demonstrating operation | movement of a hysteresis torque generation mechanism. The figure equivalent to FIG. 12 which shows other embodiment of a hysteresis torque generation mechanism. The figure equivalent to FIG. 12 which shows other embodiment of a hysteresis torque generation mechanism.

[overall structure]
FIG. 1 shows a torque converter as a fluid type power transmission device according to an embodiment of the present invention. An engine is arranged on the left side of FIG. 1, and a transmission is arranged on the right side of FIG. A line OO shown in FIG. 1 is a rotation axis of the torque converter. Note that a part of the main body of the torque converter is omitted.

  The torque converter 1 is a device for transmitting power from a crankshaft of an engine to an input shaft of a transmission, and mainly includes a front cover 2 to which power is input, an impeller 3, a turbine 4, a stator 5, And a lock-up device 6.

  The front cover 2 and the impeller 3 are fixed to each other by bolts 7 and a fluid chamber is formed by the front cover 2 and the impeller 3. The turbine 4 is disposed so as to face the impeller 3 in the fluid chamber. The turbine 4 includes a turbine shell 8, a plurality of turbine blades 9 fixed inside the turbine shell 8, and a turbine hub 10 fixed to the inner peripheral portion of the turbine shell 8. The turbine hub 10 has a cylindrical portion 10a extending in the axial direction and a disk-shaped flange 10b extending radially outward from the cylindrical portion 10a. And the inner peripheral part of the turbine shell 8 is being fixed to the outer peripheral part of the flange 10b with the rivet 13. FIG. A spline hole 10 c is formed in the inner peripheral portion of the turbine hub 10. And the input shaft of the transmission which is not illustrated is connected with the spline hole 10c. The stator 5 is a mechanism for adjusting the flow of hydraulic oil from the turbine 4 to the impeller 3, and is disposed between the impeller 3 and the turbine 4.

[Lock-up device 6]
FIG. 2 shows the lock-up device 6 taken out. The lockup device 6 is a device for mechanically connecting the front cover 2 and the turbine 4 when the engine speed reaches a predetermined speed (lockup speed), as shown in FIG. Between the front cover 2 and the turbine 4. The lockup device 6 includes a piston 15, a dynamic damper device 16, and a plurality of first torsion springs 17.

<Piston 15>
The piston 15 has a cylindrical portion 15a formed by being bent toward the engine side on the inner peripheral portion. And this cylindrical part 15a is supported by the outer peripheral surface of the cylindrical part 10a of the turbine hub 10 so that sliding is possible in an axial direction and a rotation direction. An annular friction member 18 that is pressed against the side surface of the front cover 2 is fixed to the outer peripheral portion 15 b of the piston 15.

<Dynamic damper device 16>
The dynamic damper device 16 includes a first plate 21 and a second plate 22, a hub flange 23, an inertia member 24, a plurality of second torsion springs 25, and a hysteresis torque generating mechanism 26.

-First and second plates 21, 22-
FIG. 3 shows a sectional view of the first plate 21, and FIG. 4 shows a part of FIG. 3 viewed from the IV direction.

  As shown in these drawings, the first plate 21 is a disk-shaped member, and has a circular hole 21a at the center and four engagement protrusions 21b at the outer periphery. The four engagement protrusions 21b are formed to protrude to the outer peripheral side and to be inclined to the engine side, and a plurality of first torsion springs 17 are disposed between these engagement protrusions 21b. That is, the circumferential end surfaces of the four engagement protrusions 21 b can be engaged with the circumferential ends of the first torsion springs 17.

  The first plate 21 is formed with six stop pin holes 21c on the inner peripheral side of the engaging protrusion 21b, and further, six storage portions for storing the second torsion spring 25 on the inner peripheral side thereof. 21d is formed. Three arc-shaped openings 21e are formed on the inner peripheral side of the storage portion 21d. Each of the three openings 21e is formed with an engaging recess 21f that is recessed at the inner peripheral side at both ends. Further, three spring holding openings 21g are formed between the three openings 21e in the circumferential direction.

  On the outer peripheral side of the three openings 21e and the spring holding opening 21g, a circular convex portion 21h that protrudes toward the second plate 22 is formed. The convex portion 21h is formed by extruding a part of the first plate 21 toward the second plate 22 as shown in an enlarged view in FIG. The tip of the convex portion 21h is a flat surface and protrudes from the surrounding surface to the second plate 22 side by a predetermined distance. This front end surface is in contact with the side surface of the hub flange 23.

  Also, rivet holes 21i are formed on the inner peripheral sides of the three openings 21e, respectively.

  6 and 7 are sectional views of the second plate 22, and FIG. 8 is a front view of the second plate 22. FIG. 9 shows a part of FIG. 7 viewed from the IX direction and a cross-sectional view taken along the line IX-IX. 6 is a sectional view taken along line VI-VI in FIG. 8, and FIG. 7 is a sectional view taken along line VII-VII in FIG.

  As shown in these drawings, the second plate 22 is a disk-shaped member having a circular hole 22a at the center, and six stop pin holes 22c formed at the outer periphery. Six storage portions 22d for storing the second torsion springs 25 are formed on the inner peripheral side. Three arc-shaped openings 22e are formed on the inner peripheral side of the storage portion 22d. Each of the three openings 22e is formed with an engaging recess 22f that is recessed on the inner peripheral side at both ends. Further, three spring holding openings 22g are formed between the three openings 21e in the circumferential direction.

  On the outer peripheral side of the three openings 22e and the spring holding opening 22g, a circular convex portion 22h that protrudes toward the first plate 21 is formed. The convex portion 22 h has the same shape as the convex portion 21 h formed on the first plate 21.

  Further, rivet holes 22i are respectively formed on the inner peripheral sides of the three openings 22e.

  Further, in the second plate 22, slider support portions 28 are formed at three locations on the inner peripheral side of the storage portion 22d. The slider support part 28 is a part which comprises the hysteresis torque generation mechanism 26, and supports the slider mentioned later so that a movement to radial direction is possible. Each slider support portion 28 is formed between three openings 22e as shown in FIGS. More specifically, the inner peripheral side portions of the three openings 22e have an arc shape that swells toward the inner peripheral side, and is an offset portion 22j that is extruded toward the first plate 21 side. A slider support portion 28 is formed between the three offset portions 22j in the circumferential direction. As shown in FIG. 9, the slider support portion 28 is formed with a width W1 in the circumferential direction around the spring holding opening 22g. And the edge part of the circumferential direction becomes the contact part 28a colliding with the slider mentioned later.

  As shown in FIGS. 1 and 2, the first plate 21 and the second plate 22 as described above have the inner peripheral portion of the first plate 21 and the offset portion 22j of the second plate 22 in contact with each other. The plates 21 and 22 are fixed to each other by rivets 30 that pass through the rivet holes 21i and 22i. The outer peripheral portions of both plates 21 and 22 are fixed with a predetermined gap in the axial direction by stop pins 31 penetrating through the stop pin holes 21c and 22c of the plates 21 and 22, respectively. In other words, the plates 21 and 22 are disposed to face each other with a predetermined gap set by the stop pin 31 except for a portion fixed by the rivet 30.

  On the other hand, as shown in FIGS. 1 and 2, a driven plate 33 is fixed to the flange 10 b of the turbine hub 10 by a rivet 13. The driven plate 33 is formed in an annular shape, and a plurality of claws 33a extending from the outer peripheral end by being bent toward the engine side are formed. The plurality of claws 33a are engaged with the engaging recesses 21f and 22f of the first plate 21 and the second plate 22, respectively. Accordingly, the first and second plates 21 and 22 rotate in synchronization with the turbine hub 10.

  A second torsion spring 25 is accommodated in the accommodating portions 21d and 22d of both plates 21 and 22.

-Hub flange 23 and inertia member 24-
The hub flange 23 is a disk-like member having a hole 23a at the center as shown in FIG. 11 when FIG. 10 and FIG. 10 are viewed from the XI direction. An annular inertia member 24 is fixed to the outer peripheral end of the hub flange 23 by a rivet 34. Further, in the hub flange 23, six arc-shaped long holes 23c are formed on the inner peripheral side of the portion where the inertia member 24 is mounted, and further six storage portions 23d are formed on the inner peripheral side thereof. Yes. The body of the stop pin 34 passes through the long hole 23c. Accordingly, the hub flange 23 can rotate relative to the first and second plates 21 and 22 within an angle range in which the long hole 23c is formed. Each storage portion 23d is formed at the same position as the storage portions 21d and 22d of both plates 21 and 22, and the second torsion spring 25 is stored in the storage portion 23d.

  As described above, the first and second plates 21 and 22 are formed with convex portions 21h and 22h, and these convex portions 21h and 22h are in contact with both side surfaces of the hub flange 23. Accordingly, a gap corresponding to the height of the convex portions 21h and 22h is formed between the side surface of the hub flange 23 and each of the plates 21 and 22 except for the portion where the convex portions 21h and 22h are formed.

-Hysteresis torque generating mechanism 26-
The hysteresis torque generating mechanism 26 is disposed between the first plate 21 and the second plate 22 in the axial direction, and is disposed on the inner peripheral side of the hub flange 23 in the radial direction. The hysteresis torque generating mechanism 26 generates variable hysteresis torque between the first and second plates 21 and 22 and the hub flange 23.

  FIG. 12 schematically shows the basic configuration of the hysteresis torque generating mechanism 26. Since FIG. 12 is a schematic diagram, the size, shape, and the like of each member shown in FIG. 12 are different from those in other drawings.

  The hysteresis torque generating mechanism 26 corresponds to the slider support portion 28 formed on the above-described second plate 22, three sliders 36 disposed on the slider support portion 28 so as to be movable in the radial direction, and each slider 36. And a provided spring 37.

  The slider 36 is disposed between two contact portions 28 a formed at both ends of the slider support portion 28. The outer periphery of the slider 36 is formed in an arc shape, and can contact the inner peripheral surface of the hub flange 23 (the surface of the hole 23a: hereinafter referred to as “inner peripheral end surface”). The inner peripheral portion of the slider 36 has a shape along the outer peripheral surface of the turbine hub 10, and a support protrusion 36 a that protrudes on the inner peripheral side is formed at the center portion in the circumferential direction. Further, on the outer peripheral side of the support protrusion 36a, an opening 36b for accommodating the spring 37 is formed at a position corresponding to the spring holding openings 21g and 22g of the first and second plates 21 and 22.

  A plurality of arc-shaped support recesses 10 d are formed on the outer peripheral surface of the turbine hub 10. And the support protrusion 36a of the slider 36 is supported by this support recessed part 10d. Here, as shown in FIGS. 9 and 12, the width between the contact portions 28a formed at both ends of the slider support portion 28 is W1, and the width of the slider 36 is a width W2 smaller than W1. That is, a gap is formed between the contact portions 28 a facing both side surfaces of the slider 36. For this reason, the slider 36 is movable in the radial direction and is swingable around the support protrusion 36a within the gap.

  The support protrusion 36a of the slider 36 and the contact portion 28a of the slider support portion 28 as described above constitute a pressing mechanism that presses the slider 36 against a part of the second plate 22 (contact portion 28a).

  As shown in FIG. 13, the spring 37 is accommodated in the opening 36 a of the slider 36 and is held in the spring holding openings 21 g and 22 g of the first and second plates 21 and 22. One end on the radially inner side of the spring 37 abuts on the inner peripheral side end surface of the opening 36a of the slider 36, and one end on the outer side in the radial direction is the outer peripheral side end surface of the spring holding openings 21g and 22g of the first and second plates 21 and 22. Abut. The spring 37 urges the slider 36 radially inward when the lockup device 6 is not rotating (when no centrifugal force is acting), so that the inner peripheral end face of the hub flange 23 is abutted against it. Not touching.

-Dynamic damper device positioning-
The dynamic damper device 16 described above is positioned in the axial direction and the radial direction as follows.

  That is, as shown in FIGS. 1 and 2, the first plate 21 has an inner peripheral portion that extends to the outer peripheral surface of the turbine hub 10. And this inner peripheral part is clamped by the side surface of the transmission side in the inner peripheral part of the piston 15, and the side surface of the turbine hub 10, and the movement of an axial direction is controlled. Since the first plate 21 is fixed in the axial direction with other members such as the second plate 22, the axial movement of the entire dynamic damper device is eventually restricted by restricting the movement of the first plate 21 in the axial direction. Movement is restricted.

  The piston 15 moves in the axial direction when the clutch of the lockup device is turned on and off. In this embodiment, the turbine 4 also moves in the axial direction in accordance with the movement of the piston 15. Therefore, the positional relationship among the piston 15, the dynamic damper device 16, and the turbine 4 does not change depending on whether the lock-up device clutch is on or off.

  Further, the inner peripheral surface of the first plate 21 is in contact with the outer peripheral surface of the tubular portion 10 a of the turbine hub 10. Thereby, the first plate 21 is positioned in the radial direction. Since the first plate 21 is fixed in the radial direction with other members such as the second plate 22, the first plate 21 is positioned in the radial direction, so that the dynamic damper device as a whole is positioned in the radial direction. Will be done.

<First torsion spring 17>
As shown in FIGS. 1 and 2, the plurality of first torsion springs 17 are members for elastically connecting the drive plate 40 and the first plate 21 fixed to the piston 15 in the rotational direction. In addition, the intermediate member 42 is provided so that the outer peripheral part of the some 1st torsion spring 17 and the side part by the side of a transmission may be covered. The plurality of first torsion springs 17 are restricted from moving in the axial direction and the radial direction by the piston 15 and the intermediate member 42.

  The intermediate member 42 is rotatable relative to the drive plate 40 and the first plate 21. And it is a member for making a set of two torsion springs of the plurality of first torsion springs 17 act in series.

[Operation]
First, the operation of the torque converter body will be briefly described.

  When the front cover 2 and the impeller 3 are rotating, the hydraulic oil flows from the impeller 3 to the turbine 4, and power is transmitted from the impeller 3 to the turbine 4 through the hydraulic oil. The power transmitted to the turbine 4 is transmitted to an input shaft (not shown) of the transmission via the turbine hub 10.

  When the rotational speed of the input shaft reaches a certain rotational speed, the lockup device 6 is turned on, and power is mechanically transmitted from the front cover 2 to the turbine hub 10 via the lockup device 6. Specifically, the piston 15 moves to the engine side due to a change in hydraulic pressure, and the friction material 18 of the piston 15 is pressed against the front cover 2. As a result, the piston 15 rotates integrally with the front cover 2, and power is transmitted from the front cover 2 to the turbine hub 10 via the piston 15, the first torsion spring 17, and the dynamic damper device 16.

[Operation of dynamic damper device]
In the dynamic damper device 16, the power input to the first and second plates 21 and 22 is transmitted to the turbine hub 10 via the driven plate 33. At this time, since the hub flange 23 and the inertia member 24 are provided on the first and second plates 21 and 22 via the second torsion spring 25, fluctuations in the rotation of the engine can be effectively suppressed. Less than. This point will be described in detail.

  As shown in FIG. 14, generally, when the engine speed decreases, the engine speed fluctuation caused by combustion fluctuation increases (characteristic E1). At this time, when there is no inertia member 24, that is, when there is no dynamic damper device 16, when the engine speed decreases, the rotational speed fluctuation output from the torque converter gradually increases. On the other hand, when the dynamic damper device 16 is provided as in the present embodiment, the rotational speed fluctuation of the turbine on the output side is reduced near a specific engine speed (around 1200 rpm in the example of FIG. 14). (Characteristics E2, E3).

  Here, the difference between the characteristics E2 and E3 in the low speed range is due to the magnitude of the hysteresis torque in the hysteresis torque generating mechanism 26. That is, the characteristic E2 is when the hysteresis torque is relatively large, and the characteristic E3 is when the hysteresis torque is relatively small. In the characteristic E2, the rotational speed fluctuation of the turbine is small when the engine speed is lower than 1200 rpm, becomes maximum near 1500 rpm, and gradually decreases when the engine speed is higher. On the other hand, in the characteristic E3, the rotational speed fluctuation of the turbine shows a minimum value smaller than the characteristic E2 when the engine speed exceeds 1200 rpm, and becomes the maximum exceeding the characteristic E2 near 1600 rpm.

  As is clear from these characteristics, the rotational speed fluctuation of the turbine is small when the hysteresis torque is small in the engine speed range where the engine speed is low, and is small when the hysteresis torque is large in the intermediate engine speed range. Further, in the high rotation speed range, the influence of the hysteresis torque on the turbine rotation speed fluctuation is small.

  Therefore, the hysteresis torque generating mechanism 26 according to this embodiment is configured such that the hysteresis torque changes depending on the rotational speed range. Specifically, the hysteresis torque generated by the hysteresis torque generating mechanism 26 is small in a region where the engine speed is low, and is large in regions where the engine speed is high.

[Operation of hysteresis torque generation mechanism]
The operation of changing the hysteresis torque depending on the rotational speed range will be described with reference to FIG.

  First, in the low speed range, the centrifugal force f1 acting on the slider 36 is relatively small. Therefore, as shown in FIG. 15A, the slider 36 is urged radially inward by the urging force f 2 of the spring 37, and the outer peripheral surface of the slider 36 is in contact with the inner peripheral end surface of the hub flange 23. Absent. Therefore, the hysteresis torque is relatively small. That is, only the hysteresis torque due to the friction of each part.

  As the rotational speed increases, the centrifugal force f1 acting on the slider 36 increases. When a large centrifugal force f1 is applied to the slider 36, the slider 36 moves to the outer peripheral side against the biasing force f2 of the spring 37, and as shown in FIG. The inner peripheral surface of the hub flange 23 comes into contact. Therefore, in this case, a hysteresis torque larger than the hysteresis torque in the low rotation speed region is generated.

  Further, in the state where the rotational speed fluctuation is occurring, the turbine hub 10 and the hub flange 23 are rotating in opposite phases. Therefore, the slider 36 that is in contact with the inner peripheral end surface of the hub flange 23 receives the force f3 and is shown in FIG. At 15 it tries to rotate clockwise. In such a situation, as shown in FIG. 15C, the support protrusion 36a of the slider 36 contacts the turbine hub 10 at a point c and receives a force f4 from the contact point c. Here, as described above, since a gap is formed between the both side surfaces of the slider 36 and the abutting portion 28a of the slider support portion 28, the slider 36 further receives a clockwise moment, As a result, the side surface of the slider 36 is strongly pressed against the contact portion 28a and becomes a fulcrum. In the drawing, the vicinity of the left side of the slider 36 becomes an action point, and the slider 36 is pressed more strongly against the inner peripheral surface of the hub flange 23 by the lever principle.

  As described above, the relative rotation between the first and second plates 21 and 22 and the turbine hub 10 and the hub flange 23 is compared with the situation shown in FIGS. 15 (a) and 15 (b). Further, a large hysteresis torque is generated.

  In the configuration as described above, as shown in FIG. 14, the characteristic of the turbine rotational speed fluctuation becomes the characteristic E3 in the low rotational speed range, and the characteristic E2 in the middle rotational speed range to the high rotational speed range. For this reason, the turbine rotational speed fluctuation can be kept small in the entire engine speed range.

[Feature]
(1) Since a small hysteresis torque is generated in the low rotation speed range and a larger hysteresis torque is generated in the medium rotation speed range to the high rotation speed range, fluctuations in the rotational speed of the turbine can be suppressed in a wide rotation speed range.

  (2) Since the hysteresis torque generating mechanism 26 is disposed between the first plate 21 and the second plate 22, the axial dimension of the apparatus can be made compact.

  (3) Since the hysteresis torque is changed using the centrifugal force acting on the slider 36, it is possible to generate a hysteresis torque that varies depending on the rotational speed range with a simple configuration.

  (4) The first plate 21 is sandwiched between the piston 15 and the turbine hub 10 to restrict the movement in the axial direction, and the movement in the axial direction of the dynamic damper device 16 is restricted. Further, radial positioning is performed by bringing the inner peripheral surface of the first plate 21 into contact with the outer peripheral surface of the turbine hub 10. Therefore, the dynamic damper device 16 can be positioned in the axial direction and the radial direction with a small number of parts.

  (5) The slider 36 is swung around the support protrusion 36a and pressed against the contact portion 28a of the second plate 22 as a fulcrum. Since it is strongly pressed, a large hysteresis torque can be generated with a simple mechanism.

[Other Embodiments]
The present invention is not limited to the above-described embodiments, and various changes or modifications can be made without departing from the scope of the present invention.

  (A) In the above embodiment, the torque converter is described as an example of the fluid power transmission device. However, the fluid power transmission device may be a fluid coupling that does not have a stator.

  FIG. 16 and FIG. 17 show another embodiment of a pressing mechanism for generating a large hysteresis torque by swinging the slider.

  In the embodiment shown in FIG. 16, the slider 36 'has a support recess 36a' instead of the support protrusion 36a in the previous embodiment. The support recess 36a 'has an arcuate surface that swells toward the outer periphery. On the other hand, the turbine hub 10 'is formed with a support projection 10d' that fits into the support recess 36a '. The front end surface of the support protrusion 10d 'is formed in an arc shape along the arc-shaped surface of the support recess 36a'.

  In the embodiment shown in FIG. 17, the slider 36 ″ has a support recess 36 a ″ basically configured in the same manner as the embodiment shown in FIG. 16. On the other hand, the turbine hub 10 ″ is formed with an arcuate support recess 10 d ″ that is recessed toward the inner periphery. The roller 50 is fitted in the support recesses 36a "and 10d".

  Also according to the embodiment shown in FIG. 16 and FIG. 17 as described above, the same effect as the previous embodiment can be obtained.

DESCRIPTION OF SYMBOLS 1 Torque converter 2 Front cover 3 Impeller 4 Turbine 6 Lockup apparatus 10 Turbine hub 10d, 10d '' Support recessed part 10d 'Support protrusion 15 Piston 16 Dynamic damper apparatus 17 1st torsion spring 21 1st plate 22 2nd plate 23 Hub flange 24 Inertia member 25 Second torsion spring 26 Hysteresis torque generating mechanism 28 Slider support portion 28a Contact portion 36, 36 ', 36''Slider 36a Support protrusion 36a', 36a '' Support recess 37 Spring 50 Roller

Claims (7)

A dynamic damper device disposed between a disk-like piston of a lockup device and a turbine hub of a fluid power transmission device;
A pair of annular plates that receive torque from the piston and are connectable to the turbine hub;
An annular hub flange disposed between the pair of plates and rotatable relative to the pair of plates;
An inertia member fixed to the hub flange;
An elastic member that elastically connects the pair of plates and the hub flange in a rotational direction;
A hysteresis torque generating mechanism that is arranged on the inner peripheral side of the hub flange between the pair of plates in the axial direction and generates a variable hysteresis torque between the pair of plates and the hub flange;
With
One of the pair of plates is sandwiched between a side surface on the turbine hub side and a side surface of the turbine hub in the inner peripheral portion of the piston, and axial movement is restricted,
Dynamic damper device.   The hysteresis torque generating mechanism generates a first hysteresis torque in a low rotation speed range, and generates a second hysteresis torque larger than the first hysteresis torque in a medium rotation speed range to a high rotation speed range. The dynamic damper device described. The turbine hub has a cylindrical portion extending in an axial direction on an inner peripheral portion,
Of the pair of plates, the plate sandwiched between the piston and the turbine hub has an inner peripheral surface that is in contact with the outer peripheral surface of the cylindrical portion of the turbine hub, and is positioned in the radial direction. The dynamic damper device according to claim 1 or 2. The hysteresis torque generating mechanism, wherein with the pair plates having a plurality of sliders arranged swingably movable and rotational direction with the radial direction rotates, the plurality of sliders radially outside the centrifugal force The dynamic damper device according to any one of claims 1 to 3, wherein the dynamic damper device moves in the direction toward and abuts against an inner peripheral surface of the hub flange. The hysteresis torque generating mechanism presses the plurality of sliders against at least one of the pair of plates, and applies a rotational moment to the slider in addition to the centrifugal force with the pressed portion as a fulcrum. The dynamic damper device according to claim 4 , further comprising a pressing mechanism that presses against an inner peripheral surface of the hub flange . The pressing mechanism is
An abutting portion formed on at least one of the pair of plates and arranged with a gap from a side surface in the rotational direction of the slider;
A support portion that supports the slider so as to be swingable in the rotational direction with respect to the turbine hub;
The dynamic damper device according to claim 5, comprising: A lockup device for mechanically transmitting power from a front cover to a turbine hub of a fluid power transmission device,
A piston pressed against the front cover;
A dynamic damper device according to any one of claims 1 to 6;
An elastic member that elastically connects the piston and the dynamic damper device in a rotational direction;
A lockup device for a fluid type power transmission device.

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