JP6405257B2 - Torque converter - Google Patents

Description

  The present invention relates to a torque converter including a lockup clutch.

  Generally, a torque converter has a pump impeller connected to a crankshaft via a front cover, and a turbine runner that is arranged opposite to the pump impeller and connected to a transmission input shaft. It is intended to be amplified through. Since this torque converter is a slip element that transmits engine power via hydraulic oil, it is possible to avoid engine stall at the time of start and the like and increase the drive torque, but at the time of steady running, etc. It becomes a factor causing transmission loss of engine power.

  In order to reduce transmission loss of engine power, a torque converter incorporating a lockup clutch that directly connects a crankshaft and a turbine shaft (transmission input shaft) has been developed. In this type of torque converter, the engine torque that has been amplified is input to the transmission input shaft by releasing the lock-up clutch when starting up, and the lock-up clutch is engaged during steady running. The engine power is directly input from the crankshaft to the transmission input shaft. Here, the lock-up clutch is generally equipped with a torsion damper (damper spring) for absorbing a periodic rotational fluctuation of the engine (see, for example, Patent Document 1).

  By the way, in the case of a vehicle such as an automobile, for the purpose of improving fuel efficiency, when the engine operating condition or the like satisfies a preset condition, a fuel cut (cylinder stop) is performed for some cylinders. A technique for shifting from a cylinder operation state to a partial cylinder operation state is known.

JP 2010-53963 A

  However, the engine output during partial cylinder operation as described above has a larger torque fluctuation amplitude and lower frequency than during full cylinder operation. Therefore, during partial cylinder operation, the frequency of resonance with the eigenvalue increases, and the level of silence and vibration damping tends to deteriorate.

  On the other hand, it is conceivable to reduce the rigidity of the damper corresponding to the output torque during partial cylinder operation and increase the damping performance against torque fluctuation. However, if the rigidity of the damper is reduced in this way, the output torque is high. During all-cylinder operation, the damper may reach the torsional limit without sufficiently absorbing rotational fluctuations.

  The present invention has been made in view of the above circumstances, and a torque converter capable of accurately absorbing torque fluctuations even when the number of operating cylinders of an engine is changed and realizing good quietness and vibration suppression. The purpose is to provide.

  A torque converter according to an aspect of the present invention is a torque converter connected to an engine capable of switching the number of operating cylinders according to a preset condition, and includes a pump impeller to which engine power is transmitted, and the pump impeller. A turbine runner that transmits the transmitted engine power to an output shaft via a working fluid; and a lockup mechanism having a plurality of lockup clutches that directly connect the pump impeller side and the turbine runner side so as to be able to contact and separate. The damper rigidity of the lock-up mechanism at the time of lock-up is variable according to the number of operating cylinders of the engine through a damper interposed in the power transmission path for each lock-up clutch and the engagement control of each lock-up clutch. And a lock-up control means for controlling.

  According to the torque converter of the present invention, even when the number of operating cylinders of the engine is changed, torque fluctuations can be accurately absorbed, and good silence and vibration damping can be realized.

Skeleton diagram showing vehicle power transmission system Cross section of the main part of the torque converter Explanatory drawing showing damper rigidity in each lock-up state Explanatory drawing showing engine torque and amplitude in all cylinder operation state and partial cylinder operation state Flowchart showing lockup control routine Cross-sectional view of the main part showing a modification of the torque converter

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. The drawings relate to an embodiment of the present invention, FIG. 1 is a skeleton diagram showing a power transmission system of a vehicle, FIG. 2 is a cross-sectional view of a main part of a torque converter, and FIG. 3 is an explanatory diagram showing damper rigidity in each lock-up state. FIG. 4 is an explanatory diagram showing engine torque and amplitude in the full cylinder operation state and the partial cylinder operation state, and FIG. 5 is a flowchart showing a lockup control routine.

  The vehicle power transmission system shown in FIG. 1 includes, for example, a continuously variable transmission 2 that continuously transmits power of an engine 1 that is a power source and transmits the power to drive wheels 3. Here, the engine 1 of the present embodiment is, for example, a horizontally opposed four-cylinder engine, and a predetermined part of the cylinders can be deactivated through control by an engine control unit (ECU) 100. That is, for example, when the operating point of the engine 1 determined from the load of the engine 1 and the engine speed is in a preset cylinder deactivation operation range and the accelerator opening is zero, the ECU 100 determines that some cylinders ( For example, it is possible to shift the operation state of the engine 1 from the full cylinder operation state to the partial cylinder operation state by performing a fuel cut of 2 cylinders).

  The continuously variable transmission 2 has a primary shaft 5 driven by the engine 1 and a secondary shaft 6 parallel to the primary shaft 5. A speed change mechanism 7 is provided between the primary shaft 5 and the secondary shaft 6, and a speed reduction mechanism 8 and a differential mechanism 9 are provided between the secondary shaft 6 and the drive wheel 3.

  A primary pulley 10 is provided on the primary shaft 5. The primary pulley 10 includes a fixed sheave 10a and a movable sheave 10b, and a hydraulic oil chamber 11 is formed on the back side of the movable sheave 10b. The secondary shaft 6 is provided with a secondary pulley 12. The secondary pulley 12 includes a fixed sheave 12a and a movable sheave 12b. A hydraulic oil chamber 13 is formed on the back side of the movable sheave 12b. Further, a drive chain 14 is wound around the primary pulley 10 and the secondary pulley 12. Here, the hydraulic pressure supplied to the hydraulic oil chambers 11 and 13 of the pulleys 10 and 12 is controlled by the transmission control unit (TCU) 101 based on the vehicle speed, the operating state of the engine 1 and the like. Through this hydraulic control, the continuously variable transmission between the primary shaft 5 and the secondary shaft 6 is achieved by relatively changing the groove widths of the pulleys 10 and 12 and changing the winding diameter of the drive chain 14. It is possible.

  In order to transmit engine power to such a transmission mechanism 7, the primary shaft 5 is connected to the crankshaft 1 a of the engine 1 via the forward / reverse switching mechanism 15 and the torque converter 20.

  The forward / reverse switching mechanism 15 includes a double pinion planetary gear train 16, a forward clutch 17, and a reverse brake 18. The forward / reverse switching mechanism 15 can switch the transmission path of the engine power transmitted via the torque converter 20 by controlling the engagement state of the forward clutch 17 and the reverse brake 18 by the TCU 101. ing. That is, the forward / reverse switching mechanism 15 can transmit the rotation of the turbine shaft 21 that is the output shaft of the torque converter 20 to the primary pulley 10 as it is by engaging the forward clutch 17 and releasing the reverse brake 18. It has become. On the other hand, the forward / reverse switching mechanism 15 can transmit the rotation to the primary pulley 10 by reversing the rotation of the turbine shaft 21 by releasing the forward clutch 17 and fastening the reverse brake 18.

  The torque converter 20 includes a pump impeller 30, a turbine runner 31 to which rotation of the pump impeller 30 is transmitted via a working fluid, a stator 32 interposed between the pump impeller 30 and the turbine runner 31, The lockup mechanism 33 is configured to directly connect the pump impeller 30 side and the turbine runner 31 side so as to be able to contact and separate.

  As shown in FIG. 2, the pump impeller 30 includes an outer shell 30a welded to the front cover 22 of the torque converter 20, and a plurality of pump blades 30b held inside the outer shell 30a. Yes. A crankshaft 1 a of the engine 1 is connected to the front cover 22 via a drive plate 23, and engine power is transmitted to the pump impeller 30 via the drive plate 23. Further, a sleeve 24 in which the turbine shaft 21 is inserted is connected to the outer shell 30a, and an oil pump 25 (see FIG. 1) is connected to an extended end of the sleeve 24.

  The turbine runner 31 includes a turbine shell 31a disposed to face the outer shell 30a, and a plurality of turbine blades 31b held by the turbine shell 31a. A turbine hub 35 spline-fitted to the turbine shaft 21 is rivet-coupled to the turbine shell 31 a, and engine power transmitted from the pump impeller 30 to the turbine runner 31 via the working fluid is transmitted to the turbine shell 35 via the turbine hub 35. It is transmitted to the shaft 21.

  The stator 32 includes a plurality of blades 32 a provided radially inward of the pump impeller 30 and the turbine runner 31. A one-way clutch 36 is provided on the inner peripheral side of the stator 32, and the one-way clutch 36 is supported by an intermediate member 26 that is a non-rotating member interposed between the sleeve 24 and the turbine shaft 21.

  The lockup mechanism 33 includes a plurality of lockup clutches that directly connect the pump impeller 30 side and the turbine runner 31 side so as to be able to contact and separate. In the present embodiment, more specifically, the lockup mechanism 33 includes a first lockup clutch 40, a second lockup clutch 41, and a lockup clutch 41 that are arranged side by side in the axial direction of the turbine shaft 21. It is comprised.

  The first lock-up clutch 40 has a first lock-up disk 45, and the first lock-up disk 45 is slidably supported by a clutch hub 43 that is splined to the turbine shaft 21. . A first friction plate 46 is fixed to the outer peripheral portion of the first lockup disk 45 by welding or the like. The first friction plate 46 is an engagement surface 22 a formed on the inner surface of the front cover 22. It is opposed to. The first friction plate 46 can be engaged with and separated from the engagement surface 22a as the first lock-up disk 45 advances and retreats in the axial direction of the turbine shaft 21. Yes. The first lock-up disk 45 is also provided with a first spring seat 47 that is rivet-coupled to the clutch hub 43 so as not to rotate. The first spring seat 47 is formed with a spring receiver 47a at every predetermined rotation angle, and a damper spring 48 as a damper is held between the pair of first holding plates 49a and 29b in each spring receiver 47a. It is housed in the state. Further, on the outer peripheral side of the first holding plates 49a and 49b, a first locking plate 50 that is non-rotatably locked to the outer peripheral portion of the first lockup disk 45 is rivet-coupled.

  In the present embodiment, the first spring seat 47, the first holding plates 49a and 49b, and the first locking plate 50 are used when the first friction plate 46 is engaged with the engagement surface 22a. That is, when the first lock-up clutch 40 is engaged, a first power transmission path for transmitting engine power from the pump impeller 30 side to the turbine runner 31 side without passing the working fluid is configured. In the first power transmission path, the first friction plate 46 has a predetermined damper rigidity (spring constant) K1 and a predetermined torsion angle range θmax by interposing the first damper spring 48. It is possible to elastically displace the side and the clutch hub 43 side.

  The second lock-up clutch 41 has a second lock-up disk 55, and the second lock-up disk 55 is slidably supported on the turbine hub 35. A second friction plate 56 is fixed to the outer peripheral portion of the second lock-up disk 55 by welding or the like, and the second friction plate 56 is attached to the engagement surface 22a of the front cover 22 with a first friction. Opposed through the plate 46. The second friction plate 46 can be brought into and out of contact with the engagement surface 22a via the first friction plate 46 as the second lock-up disk 55 advances and retreats in the axial direction of the turbine shaft 21. Can be engaged. That is, the second friction plate 56 can be engaged with the first friction plate 46 in a superimposed manner with respect to the engagement surface 22a. The second lockup disk 55 is provided with a second spring seat 57 that is rivet-coupled to the turbine hub 35 so as not to rotate. The second spring seat 57 is formed with a spring receiver 57a at every predetermined rotation angle, and each spring receiver 57a has a second damper spring 58 as a damper between a pair of second holding plates 59a and 59b. It is accommodated in the state held by the. Further, on the outer peripheral side of the second holding plates 59a and 59b, a second locking plate 60 that is non-rotatably locked to the outer peripheral portion of the second lock-up disk 55 is rivet-coupled.

  In the present embodiment, the second spring seat 57, the second holding plates 59a, 59b, and the second locking plate 60 are used when the second friction plate 56 is engaged with the engagement surface 22a. That is, when the second lock-up clutch 41 is engaged, a second power transmission path for transmitting engine power from the pump impeller 30 side to the turbine runner 31 side without the working fluid is configured. In the second power transmission path, the second friction plate 56 has a predetermined damper rigidity (spring constant) K2 and a predetermined torsion angle range θmax by interposing the second damper spring 58. It is possible to elastically displace the side and the turbine hub 35 side.

  Further, in order to realize the fastening control for the first and second lockup clutches 40 and 41 through the hydraulic control by the TCU 101, the turbine shaft 21 has a rear side (that is, the first lockup clutch 40). The first hydraulic apply passage 21a for supplying the control hydraulic pressure to the first and second lock-up clutches 40 and 41, and the rear side of the second lock-up clutch 41 (that is, the second lock-up clutch 41). A second hydraulic application passage 21b for supplying a control hydraulic pressure to the turbine runner 31) and the front side of the first lockup clutch 40 (that is, between the first lockup clutch 40 and the front cover 22). And a release passage 21c for supplying and discharging control hydraulic pressure.

  Here, the first lock-up clutch 40 is engaged when a preset lock-up condition is satisfied during full cylinder operation and partial cylinder operation. The damper rigidity K1 of the first damper spring 48 interposed in the first lockup clutch 40 is set based on the engine torque T (maximum torque Tmax1) during partial cylinder operation. That is, for example, as shown in FIG. 3, the damper rigidity K <b> 1 maximizes the damper torsion angle θ of the first lockup clutch 40 when the output torque T of the engine 1 during partial cylinder operation reaches the maximum torque Tmax <b> 1. It is set to allow up to torsion angle θmax.

  On the other hand, the second lockup clutch 41 is engaged only when a preset lockup condition is satisfied during all cylinder operation. The damper stiffness K2 of the second damper spring 58 interposed in the second lockup clutch 41 is set based on the engine torque T (maximum torque Tmax2) and the damper stiffness K1 during all cylinder operation. That is, for example, as shown in FIG. 3, the damper rigidity K2 exhibits the damper rigidity (K1 + K2) in cooperation with the first damper spring 48, and the output torque T of the engine 1 during all cylinder operation is the maximum torque Tmax2. Is set so that the damper torsion angles θ of the first and second lock-up clutches 40 and 41 are both allowed up to the maximum torsion angle θmax.

  In this case, for example, as shown in FIG. 2, in order to efficiently accommodate the first and second lock-up clutches 40 and 41 in the front cover 22, the first and second damper springs 48 and 58 are It is desirable that the turbine shafts 21 are arranged to be staggered in the radial direction.

  Next, lock-up control for the lock-up mechanism 33 executed in the TCU 101 will be described with reference to the flowchart of the lock-up control routine shown in FIG.

  This routine is repeatedly executed every set time. When the routine is started, the TCU 101 first determines in step S101, for example, the current running state of the own vehicle in advance based on the own vehicle speed and the throttle opening. Check whether the set lockup condition is satisfied.

  If it is determined in step S101 that the lockup condition is not satisfied, the TCU 101 proceeds to step S105, performs release control of the first and second lockup clutches 40 and 41, and then exits the routine. That is, the TCU 101 releases the first and second lockup clutches 40 and 41 from the engagement surface 22a by supplying control oil pressure from the release passage 21c to the front side of the first lockup clutch 40, for example. To do.

  On the other hand, if it is determined in step S101 that the lockup condition is satisfied, the TCU 101 proceeds to step S102 and checks whether the engine 1 is under cylinder stop control based on a signal from the ECU 100.

  When it is determined in step S102 that the engine 1 is under cylinder stop control (that is, when it is determined that partial cylinder operation is being performed), the TCU 101 proceeds to step S103 and only the first lockup clutch 40 is detected. After performing the fastening control, the routine is exited. That is, for example, the TCU 101 supplies only the first lockup clutch 40 to the engagement surface 22a by supplying the control oil pressure from the first hydraulic apply passage 21a to the back side of the first lockup clutch 40. Engage.

  As a result, the torque converter 20 is locked up by the damper rigidity K1 having a good damping performance, and the torque fluctuations that change with a large amplitude and a low frequency at a torque T that is relatively lower than that during all-cylinder operation (see FIG. 4). ) Is accurately absorbed.

  On the other hand, when it is determined in step S102 that the engine 1 is not under cylinder stop control (that is, when it is determined that all cylinders are operating), the TCU 101 proceeds to step S104, for example, the second lock-up clutch 41. By supplying the control hydraulic pressure from the second hydraulic apply passage 21b to the rear side of the first and second lockup clutches 40 and 41, the first and second lockup clutches 40 and 41 are engaged with the engagement surface 22a in a superimposed manner.

  As a result, the torque converter 20 is locked up by the high damper rigidity (K1 + K2), and the torque fluctuation (see FIG. 4) that changes with a small amplitude and a high frequency at a torque T that is relatively higher than that during partial cylinder operation. It is absorbed accurately without reaching the torsional limit.

  According to such an embodiment, the first and second lockup clutches 40 and 41 are provided in the lockup mechanism 33 that directly connects the pump impeller 30 side and the turbine runner 31 side so as to be able to come into contact with and away from each other. First and second damper springs 48 and 58 are interposed for the first and second power transmission paths formed by the second lockup clutches 40 and 41, respectively. , 41, the damper rigidity at the time of lock-up by the lock-up mechanism 33 is variably controlled in accordance with the number of operating cylinders of the engine 1, so that the torque can be accurately increased even when the number of operating cylinders of the engine 1 is changed. Absorbing the fluctuation, it is possible to achieve good silence and vibration control.

  That is, for example, during partial cylinder operation in which only two cylinders of four cylinders are operated, only the first lockup clutch 40 is engaged and the torque fluctuations of the engine 1 are absorbed only by the first damper spring 48. Torque fluctuations that change with a large amplitude and a low frequency can be accurately absorbed by the damper rigidity K1 having a good damping performance. On the other hand, for example, during all-cylinder operation in which all four cylinders are operating, the first and second lock-up clutches 40 and 41 are engaged, and the torque fluctuations of the engine 1 are absorbed by the first and second damper springs 48 and 58. As a result, torque fluctuations that change at a high torque T can be accurately absorbed without reaching the torsional limit of the damper.

  In this case, the first and second lock-up clutches 40 and 41 are arranged side by side in the axial direction of the turbine shaft 21, and the first and second friction plates are opposed to the engagement surface 22 a of the front cover 22. By adopting a configuration in which 46 and 56 can be engaged (fastened) in a superimposed manner, even when the first and second lock-up clutches 40 and 41 are provided in the lock-up mechanism 33, a new engagement surface 22a. Therefore, it is possible to effectively prevent the front cover 22 and the like from being enlarged in the radial direction. In addition, since the first damper spring 48 can be shared during partial cylinder operation and all cylinder operation of the engine 1, it is possible to efficiently realize damper rigidity suitable for each operation.

  Further, by arranging the first and second damper springs 48 and 58 alternately in the radial direction of the turbine shaft 21, the first and second power transmission paths of the first and second lockup clutches 40 and 41 are provided. Even when the first and second damper springs 48 and 58 are provided every time, it is possible to effectively prevent the front cover 22 and the like from being enlarged in the axial direction.

  In addition, this invention is not limited to each embodiment described above, A various deformation | transformation and change are possible, and they are also in the technical scope of this invention. For example, in the above-described embodiment, two types of operating states, that is, an all-cylinder operating state in which all four cylinders of the engine 1 are operating and a partial cylinder operating state in which two of the four cylinders are operating. As an example, the first and second lock-up clutches 40 and 41 are provided in the lock-up mechanism 33 and the first and second damper springs 48 and 58 are interposed therebetween. For example, a 6-cylinder engine is in an all-cylinder operation state in which all 6 cylinders are operating, and a first partial cylinder operation state in which 3 out of 6 cylinders are in operation. When the cylinder is controlled in three operating states, ie, the second partial cylinder operating state in which two of the six cylinders are operating, the damper rigidity K can be varied according to the number of operating cylinders. First to third lock-up The latch is provided, it is also possible to interposed first to third damper spring thereto.

  In the above-described embodiment, an example of the configuration in which the first and second lock-up clutches 40 and 41 constituting the lock-up mechanism 33 are fastened is described, but the present invention is limited to this. For example, as shown in FIG. 6, the first and second friction plates 46 and 56 are arranged side by side in the radial direction of the turbine shaft 21, and are individually fastened (engaged) to the engagement surface 22a. A possible configuration is also possible. In the example shown in FIG. 6, an example of a configuration in which the first and second friction plates 46 and 56 are integrally formed with the first and second lockup disks 45 and 55 by pressing or the like is shown. . Further, the first and second lock-up clutches 40 and 41 can be individually engaged as described above, and the damper rigidity of the first and second damper springs 48 and 58 interposed therebetween is adjusted to an appropriate value. Then, the damper rigidity when only the first lockup clutch 40 is engaged, the damper rigidity when only the second lockup clutch 41 is engaged, and the first and second lockup clutches 40 and 41 are Three types of damper rigidity can be realized: damper rigidity when fastened together.

DESCRIPTION OF SYMBOLS 1 ... Engine 1a ... Crankshaft 2 ... Continuously variable transmission 3 ... Drive wheel 5 ... Primary shaft 6 ... Secondary shaft 7 ... Transmission mechanism 8 ... Deceleration mechanism 9 ... Differential mechanism 10 ... Primary pulley 10a ... Fixed sheave 10b ... Movable sheave DESCRIPTION OF SYMBOLS 11 ... Hydraulic oil chamber 12 ... Secondary pulley 12a ... Fixed sheave 12b ... Movable sheave 13 ... Hydraulic oil chamber 14 ... Drive chain 15 ... Forward / reverse switching mechanism 16 ... Planetary gear train 17 ... Forward clutch 18 ... Reverse brake 20 ... Torque converter 21 ... Turbine shaft 21a ... First hydraulic apply passage 21b ... Second hydraulic apply passage 21c ... Release passage 22 ... Front cover 22a ... Engagement surface 23 ... Drive plate 24 ... Sleeve 25 ... Oil pump 26 ... Intermediate member 30 ... Pump Impeller 30 ... outer shell 30b ... pump blade 31 ... turbine runner 31a ... turbine shell 31b ... turbine blade 32 ... stator 32a ... blade 33 ... lockup mechanism 35 ... turbine hub 36 ... one-way clutch 40 ... first lockup clutch 43 ... clutch hub 45 First lock-up disk 46 First friction plate 47 First spring seat 47a Spring receiver 48 First damper springs 49a, 29b First holding plate 50 First locking plate 55 Second lock-up disk 56 Second friction plate 57 Second spring seat 57a Spring receiver 58 Second damper spring 59a, 59b Second holding plate 60 Second locking plate 100 … Engine system Control unit 101 ... Transmission control unit (lock-up control means)

Claims (3)

A torque converter connected to an engine capable of switching the number of operating cylinders according to a preset condition,
A pump impeller to which engine power is transmitted;
A turbine runner for transmitting the engine power transmitted to the pump impeller to an output shaft via a working fluid;
A lockup mechanism having a plurality of lockup clutches that directly connect the pump impeller side and the turbine runner side so as to be able to contact and separate;
A damper interposed in a power transmission path for each lock-up clutch;
A torque converter comprising: lockup control means for variably controlling the damper rigidity at the time of lockup by the lockup mechanism according to the number of operating cylinders of the engine through the engagement control for each lockup clutch. .   The plurality of lock-up clutches are arranged side by side in the axial direction of the output shaft, and the pump impeller side and the turbine runner side can be directly connected by overlapping fastening. Torque converter as described in.   The torque converter according to claim 1 or 2, wherein the dampers interposed in the power transmission path of each lockup clutch are alternately arranged in the radial direction of the output shaft.

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