JP2009208733A - Driving system control device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To learn a control signal corresponding to a fastening starting point of a transfer clutch. <P>SOLUTION: Driving force is directly transmitted to a front wheel output shaft, while the driving force is distributed to a rear wheel output shaft via the transfer clutch. The transfer clutch is a hydraulic clutch to which working fluid regulated in pressure by a duty control valve is supplied. When vibration of the number Nr of rotation of the rear wheel output shaft is detected under a turning traveling state (a code α2), reduction of a duty ratio Rd is started (a code β2). When vibration appearing in the number Nr of rotation of the rear wheel output shaft disappears by reducing the duty ratio Rd (a code γ2), a control unit learns the duty ratio Rd (a code δ2) at the time as a duty ratio Rd of the control signal corresponding to the fastening starting point of the transfer clutch. As a result, the transfer clutch can be controlled with high accuracy, and a torque distribution ratio of front and rear wheels can be controlled with high accuracy. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a drive system control device that distributes drive force to driven wheels via a hydraulic clutch.

  A four-wheel drive vehicle has been developed in which the torque distribution ratio of the front and rear wheels is changed according to the driving situation. Such a four-wheel drive vehicle has one main driving wheel before and after the driving torque is directly transmitted from the transmission mechanism, and the other slave driving wheel before and after the driving torque is transmitted from the transmission mechanism via the transfer clutch. The torque distribution ratio of the front and rear wheels is controlled by adjusting the fastening force of the transfer clutch.

  By the way, since the torque distribution ratio of the front and rear wheels is controlled according to the fastening force of the transfer clutch, it is important to control the transfer clutch with high accuracy in order to improve traveling performance. For example, when controlling the engagement force of the transfer clutch, a control signal corresponding to the target engagement force is output from the control unit to the hydraulic control valve, and the clutch pressure supplied to the transfer clutch is adjusted by the hydraulic control valve. The transfer clutch performs an engaging operation according to the clutch pressure, and controls the torque distribution ratio of the front and rear wheels by adjusting the engaging force. However, since the operating characteristics of the transfer clutch fluctuate due to individual clutch differences and aging, it is necessary to periodically learn the relationship between the control signal from the control unit and the operating state of the transfer clutch. Yes. In particular, learning a control signal corresponding to an engagement start point that is a boundary between a released state and a slip state is important in controlling the transfer clutch with high accuracy.

As described above, as a method of learning the engagement start point of the clutch mechanism, it is common to monitor the increase and decrease of the input side rotation speed and the output side rotation speed of the clutch mechanism while gradually switching the clutch mechanism to the engagement state. is there. For example, when learning the engagement start point of the input clutch connected to the engine via the torque converter, the input clutch is gradually switched from the released state to the engaged state, and the drop in the input side rotational speed of the input clutch is monitored. A learning apparatus has been proposed (see, for example, Patent Document 1). In addition, when learning the engagement start point of the input clutch connected to the engine, a learning device that gradually switches the input clutch from the released state to the engaged state and monitors the increase in the output side rotational speed of the input clutch is provided. It has been proposed (see, for example, Patent Document 2).
JP 2002-295529 A Japanese Patent Laid-Open No. 60-11722

  However, in the learning methods described in Patent Literature 1 and Patent Literature 2, since the change in the input side rotational speed and the output side rotational speed of the clutch mechanism are monitored, this learning method is used as a transfer clutch. It was difficult to apply. That is, since the transfer clutch is a clutch that connects the front wheel drive system and the rear wheel drive system, even when the transfer clutch is switched to the engaged state or the released state, in a traveling situation in which no slip or the like occurs on the wheels, There is no change in the input side speed or output side speed. Therefore, it is extremely difficult to learn the control signal corresponding to the engagement start point of the transfer clutch by monitoring the increase and decrease of the input side rotational speed and the output side rotational speed when the operating state of the transfer clutch is switched. It was.

  An object of the present invention is to learn a control signal corresponding to an engagement start point of a hydraulic clutch that distributes driving force to driven wheels.

  The drive system control device of the present invention is a drive system control device that drives a main drive wheel and a slave drive wheel using a drive force output from a drive source, and is between the drive source and the main drive wheel. A drive side output shaft that is provided between the drive source and the slave drive wheel and transmits the drive force to the slave drive wheel. A hydraulic clutch that is provided between a shaft, the drive source, and the slave drive side output shaft, and distributes the driving force to the slave drive wheel; and is connected to a hydraulic oil chamber of the hydraulic clutch, On the basis of a clutch control valve that controls supply of hydraulic oil, clutch control means that outputs a control signal to the clutch control valve and controls the fastening force of the hydraulic clutch, and a rotational state of the driven-side output shaft , Whether or not a predetermined vibration is generated in the slave drive side output shaft And a control signal for the clutch control means based on a change in the vibration state of the output shaft on the driven side when the control signal from the clutch control means is changed under the turning traveling state. And a learning means for learning a relationship between the engagement start point of the hydraulic clutch.

  In the drive system control device according to the present invention, the clutch control means outputs a control signal at a predetermined pulse frequency to the clutch control valve, and the vibration detection means is based on the rotation state of the slave drive side output shaft. The vibration frequency of the driven-side output shaft is calculated, and when the vibration frequency converges within a predetermined range set based on the pulse frequency, it is determined that the predetermined vibration is generated on the driven-side output shaft. It is characterized by that.

  The drive system control device according to the present invention changes the control signal of the clutch control means to the clutch disengagement side when the predetermined vibration is generated in the slave drive side output shaft under the turning traveling state, and the learning is performed. The means learns a control signal when a predetermined vibration disappears from the driven-side output shaft as a control signal corresponding to an engagement start point of the hydraulic clutch.

  The drive system control device according to the present invention changes the control signal of the clutch control means to the clutch engagement side when the predetermined vibration is not generated on the driven drive side output shaft under the turning traveling state, and the learning is performed. The means learns a control signal when a predetermined vibration is generated on the driven-side output shaft as a control signal corresponding to the engagement start point of the hydraulic clutch.

  The drive system control device of the present invention has a steering angle sensor for detecting the steering angle of the steering 54, and the learning means controls the control signal of the clutch control means in a state where the steering angle exceeds a predetermined value. And learning the relationship between the engagement start point of the hydraulic clutch.

  The drive system controller of the present invention has a main drive side rotation sensor that detects the rotation speed of the main drive side output shaft, and a slave drive side rotation sensor that detects the rotation speed of the slave drive side output shaft, The learning means has a control signal of the clutch control means and an engagement start point of the hydraulic clutch in a state where the rotational speed difference between the main drive side output shaft and the slave drive side output shaft exceeds a predetermined value. It is characterized by learning the relationship.

  According to the present invention, by changing the control signal from the clutch control means under the turning traveling state, the engagement start point of the hydraulic clutch is detected based on the change in the vibration state of the driven-side output shaft at this time. It becomes possible to do. As a result, the relationship between the control signal of the clutch control means and the engagement start point of the hydraulic clutch can be learned. Therefore, the torque distribution ratio between the main drive wheel and the slave drive wheel can be controlled with high accuracy, and the running performance of the vehicle can be improved.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a skeleton diagram showing an automatic transmission 10 of a four-wheel drive vehicle equipped with a drive system control device according to an embodiment of the present invention. As shown in FIG. 1, the automatic transmission 10 includes a transmission input shaft 12 coupled to an engine 11 that is a drive source, and a transmission output shaft 14 coupled thereto via a transmission mechanism 13. . A front wheel output shaft 16 that is a main drive side output shaft is connected to the speed change output shaft 14 via a gear train 15, and a slave drive side output shaft is connected to the speed change output shaft 14 via a transfer clutch 17 that is a hydraulic clutch. The rear wheel output shaft 18 is connected.

  The driving force output from the speed change mechanism 13 is transmitted from the front wheel output shaft 16 through the front differential mechanism 20 to the front wheels 21 that are the main driving wheels. The driving force output from the speed change mechanism 13 is transmitted to the rear wheel output shaft 18 via the transfer clutch 17, and is then driven from the rear wheel output shaft 18 to the driven wheel via the propeller shaft 22 and the rear differential mechanism 23. Is transmitted to the rear wheel 24. That is, by controlling the fastening force of the transfer clutch 17, it is possible to control the torque distribution ratio of the front and rear wheels 21, 24 by adjusting the driving force distributed to the rear wheels 24.

  A driving force is transmitted from the engine 11 to the speed change mechanism 13 via the torque converter 30. The torque converter 30 includes a pump impeller 33 coupled to the crankshaft 31 via a front cover 32 and a turbine runner 34 facing the pump impeller 33. A turbine shaft 35 is coupled to the turbine runner 34, and one end of the transmission input shaft 12 is coupled to the turbine shaft 35. The torque converter 30 that is a sliding element is provided with a lock-up clutch 36 that directly connects the crankshaft 31 and the turbine shaft 35 in order to improve the transmission efficiency of engine power.

  The speed change mechanism 13 to which the driving force is transmitted via the torque converter 30 is constituted by a plurality of planetary gear trains, clutches, brakes, and the like. By controlling the clutch and brake incorporated in the speed change mechanism 13, the transmission path of the drive force from the speed change input shaft 12 to the speed change output shaft 14 can be switched, and the drive force is transferred from the speed change input shaft 12 to the speed change output shaft 14. It is possible to transmit at a variable speed.

  FIG. 2 is a cross-sectional view showing the transfer clutch 17 and the vicinity thereof. As shown in FIG. 2, the transfer clutch 17 includes a clutch hub 40 fixed to the transmission output shaft 14 and a clutch drum 41 fixed to the rear wheel output shaft 18. A plurality of clutch plates 42 are incorporated between the clutch hub 40 and the clutch drum 41, and a hydraulic piston 43 is slidably accommodated in the clutch drum 41. By supplying the hydraulic oil to the hydraulic oil chamber 44 defined by the hydraulic piston 43 and the clutch drum 41, the clutch plate 42 is pressed by the hydraulic piston 43, and the transfer clutch 17 is switched to the engaged state. On the other hand, by discharging the hydraulic oil from the hydraulic oil chamber 44, the pressing state of the clutch plate 42 is released by the spring 45, and the transfer clutch 17 is switched to the released state. That is, by raising the hydraulic pressure supplied to the hydraulic oil chamber 44, the driving force transmitted to the rear wheel 24 is raised, while by lowering the hydraulic pressure supplied to the hydraulic oil chamber 44, the rear wheel 24 is driven. The transmitted driving force is lowered.

  FIG. 3 is a block diagram showing a control system of the transfer clutch 17. As shown in FIG. 3, the hydraulic oil discharged from the oil pump 50 is regulated through a clutch pressure control valve (clutch control valve) 52 in the valve unit 51 and supplied to the hydraulic oil chamber 44 of the transfer clutch 17. Has been. The clutch pressure control valve 52 is a duty control valve that adjusts the hydraulic oil according to the ratio (duty ratio Rd) between the energization time and the non-energization time for the solenoid. The control unit 53 adjusts the engagement ratio of the transfer clutch 17 by adjusting the duty ratio Rd of the control signal output to the clutch pressure control valve 52 so as to control the torque distribution ratio of the front and rear wheels 21, 24. I have to.

  A plurality of various sensors are connected to the control unit 53 that functions as clutch control means, vibration detection means, and learning means, and the control unit 53 of the transfer clutch 17 is based on various signals input from the various sensors. A target engagement force is set, and a control signal is output to the clutch pressure control valve 52 at a duty ratio Rd corresponding thereto. The various sensors connected to the control unit 53 include a steering angle sensor 55 that detects the steering angle Sa of the steering 54, a front wheel rotation sensor (main drive side rotation sensor) 56 that detects the rotation speed of the front wheel output shaft 16, and a rear wheel. A rear wheel rotation sensor (slave drive side rotation sensor) 57 that detects the rotation speed of the output shaft 18, a wheel speed sensor 58 that individually detects the rotation speeds of the front and rear wheels 21 and 24, and a throttle opening that detects the opening of the throttle valve. A degree sensor 59, an accelerator opening sensor 60 for detecting the operation amount of the accelerator pedal, an engine rotation sensor 61 for detecting the rotation speed of the crankshaft 31, a turbine rotation sensor 62 for detecting the rotation speed of the turbine shaft 35, and the like. Yes. The control unit 53 includes a CPU that calculates various control signals, a ROM that stores various control data and control programs, a RAM that temporarily stores data, and the like. In the following description, the rotational speed of the front wheel output shaft 16 is described as a front wheel output shaft rotational speed Nf, and the rotational speed of the rear wheel output shaft 18 is described as a rear wheel output shaft rotational speed Nr.

  Subsequently, learning control of the transfer clutch 17 executed by the control unit 53 will be described. As described above, since the torque distribution ratio of the front and rear wheels 21 and 24 is controlled by controlling the fastening force of the transfer clutch 17, in order to improve the control performance of the torque distribution ratio and improve the power performance, the control unit It is necessary to periodically learn the relationship between the control signal 53 and the operating state of the transfer clutch 17. In particular, learning a control signal corresponding to an engagement start point (a boundary between a released state and a slip state) of the transfer clutch 17 that starts transmission of a predetermined torque is extremely important for controlling the transfer clutch 17 with high accuracy. It has become.

  First, the traveling state of the vehicle in which the learning control of the transfer clutch 17 is executed will be described. FIG. 4 is an explanatory view showing a turning traveling state of the four-wheel drive vehicle. As shown in FIG. 4, when turning, there is a difference between the turning radius Rf of the front wheel 21 and the turning radius Rr of the rear wheel 24, so that a difference in rotation occurs between the front wheel 21 and the rear wheel 24. During such turning, the transfer clutch 17 is controlled to be in a slip state so that the transfer clutch 17 absorbs the rotational difference between the front and rear wheels 21 and 24 and smoothly travels the vehicle.

  Here, since the hydraulic pressure supplied to the hydraulic oil chamber 44 of the transfer clutch 17 is regulated by alternately switching the clutch pressure control valve 52 between the energized state and the non-energized state, the hydraulic pressure is controlled by the clutch pressure control valve. It fluctuates up and down with the pulse frequency of the control signal for 52. That is, in the slip control of the transfer clutch 17 that slides the clutch plate 42, the microscopic engagement and release of the clutch plate 42 are repeated as the operating hydraulic pressure fluctuates up and down. Such a stick-slip phenomenon is a factor that causes the drive system 64 on the rear wheel side, which has a smaller inertial force than the drive system 63 on the front wheel side, to vibrate. Therefore, the control unit 53 detects the engagement start point of the transfer clutch 17 from the vibration state of the drive system 64 on the rear wheel side, and learns a control signal corresponding to the engagement start point of the transfer clutch 17. . The front wheel side drive system 63 is a drive system including the speed change mechanism 13, the speed change output shaft 14, the gear train 15, the front wheel output shaft 16, and the like. The rear wheel side drive system 64 is a drive system constituted by the rear wheel output shaft 18, the propeller shaft 22, and the like.

  Hereinafter, learning control of the transfer clutch 17 will be described. FIG. 5 is a flowchart illustrating an example of a learning permission determination procedure for determining whether or not to perform learning control, and FIG. 6 is a flowchart illustrating an example of a learning control procedure. As shown in FIG. 5, in step S1, it is determined based on the output signal from the steering angle sensor 55 whether or not the steering angle Sa exceeds a predetermined value A (for example, 90 °). When the steering angle Sa is less than the predetermined value A, it is a traveling state in which the difference in rotation between the front and rear wheels 21 and 24 is difficult to appear, so that the process proceeds to step S2 and normal engagement control for the transfer clutch 17 without permitting learning control. (Hereinafter referred to as normal control) is executed to exit the routine. On the other hand, when the steering angle Sa exceeds the predetermined value A in step S1, the traveling state in which a rotational difference appears in the front and rear wheels 21 and 24 is reached, so that the process proceeds to step S3 and is based on the output signal from the wheel speed sensor 58. Thus, it is determined whether or not the vehicle speed V is within a predetermined range B (for example, 5 km to 10 km).

  If it is determined in step S3 that the vehicle speed V is out of the predetermined range B, the process proceeds to step S2, normal control is executed, and the routine is exited. On the other hand, if it is determined that the vehicle speed V is within the predetermined range B, the process proceeds to step S4, where the throttle opening degree Th is determined based on the output signal from the throttle opening degree sensor 59 within the predetermined range C (eg, 0% to 0%). 10%) is determined. If it is determined in step S5 that the throttle opening degree Th is out of the predetermined range C, the process proceeds to step S2 where normal control is executed and the routine is exited. On the other hand, if it is determined that the throttle opening degree Th is within the predetermined range C, the process proceeds to step S5, where learning control of the transfer clutch 17 is permitted. In addition to determining that the vehicle is turning based on the steering angle Sa, the transfer is performed when the vehicle speed V is within the predetermined range B or the throttle opening degree Th is within the predetermined range C. The learning control of the clutch 17 is permitted, but this is for improving the learning accuracy and ensuring safety.

  If execution of learning control is permitted along the flowchart of FIG. 5, learning control is executed along the flowchart of FIG. As shown in FIG. 6, in step S <b> 10, it is determined whether or not a predetermined vibration is generated on the rear wheel output shaft 18. Here, the predetermined vibration of the rear wheel output shaft 18 is vibration generated in association with the stick-slip phenomenon of the transfer clutch 17. In step S10, the control unit 53 calculates the vibration frequency (vibration state) of the front wheel output shaft 16 from the front wheel output shaft rotation speed Nf, and whether or not the vibration frequency has converged to a predetermined range D (for example, 40 Hz to 60 Hz). Determine whether. When the vibration frequency has converged to the predetermined range D, it is determined that the predetermined vibration accompanying the stick-slip phenomenon is occurring on the rear wheel output shaft 18. On the other hand, when the vibration frequency is out of the predetermined range D, it is determined that the predetermined vibration accompanying the stick-slip phenomenon has not occurred on the rear wheel output shaft 18. The predetermined range D is a range in which a predetermined width is given to the pulse frequency (for example, 50 Hz) of the control signal for the clutch pressure control valve 52.

  If it is determined in step S10 that the predetermined vibration is generated in the rear wheel output shaft 18, a state in which the stick-slip phenomenon occurs in the transfer clutch 17, that is, the transfer clutch 17 exceeds the engagement start point. Since the state is controlled to the engagement side, the process proceeds to step S11, and the duty ratio Rd of the control signal is lowered to the clutch release side. Subsequently, the process proceeds to step S12, where it is determined whether or not the predetermined vibration generated in the rear wheel output shaft 18 has disappeared. If it is determined in step S12 that the predetermined vibration of the rear wheel output shaft 18 has not disappeared, since the stick-slip phenomenon of the transfer clutch 17 is continuing, the predetermined vibration of the rear wheel output shaft 18 is maintained. In step S11, the duty ratio Rd of the control signal is reduced until the current disappears.

  When it is determined in step S12 that the predetermined vibration of the rear wheel output shaft 18 has disappeared, the stick-slip phenomenon of the transfer clutch 17 is eliminated, that is, the transfer clutch 17 is controlled to the engagement start point. Therefore, the process proceeds to step S13, and the duty ratio Rd of the current control signal is stored in association with the engagement start point of the transfer clutch 17. In step S13, after learning the relationship between the control signal and the fastening start point, the process proceeds to step S14 to return to normal control and exit the routine.

  On the other hand, if it is determined in step S10 that the predetermined vibration is not generated in the rear wheel output shaft 18, the transfer clutch 17 is in a state where the stick-slip phenomenon has not occurred, that is, the transfer clutch 17 is set to the engagement start point. Since it is in the state of being controlled to the disengagement side below, the process proceeds to step S15, and the duty ratio Rd of the control signal is raised to the clutch engagement side. Then, it progresses to step S16 and it is determined whether the predetermined vibration generate | occur | produced in the rear-wheel output shaft 18. FIG. If it is determined in step S16 that the predetermined vibration is not generated in the rear wheel output shaft 18, the transfer clutch 17 is in a released state, and thus the predetermined vibration is generated in the rear wheel output shaft 18. In step S15, the duty ratio Rd of the control signal is increased.

  If it is determined in step S16 that the predetermined vibration is generated in the rear wheel output shaft 18, the state in which the stick-slip phenomenon has occurred in the transfer clutch 17, that is, the transfer clutch 17 is controlled to the engagement start point. Therefore, the process proceeds to step S13, and the duty ratio Rd of the current control signal is stored in association with the engagement start point of the transfer clutch 17. In step S13, after learning the relationship between the control signal and the fastening start point, the process proceeds to step S14 to return to normal control and exit the routine.

  Thus, the vibration state of the rear wheel output shaft 18 is changed by changing the control signal from the control unit 53 under a turning traveling state in which a rotational difference occurs between the front and rear wheels 21 and 24. . Since the engagement start point of the transfer clutch 17 can be detected based on the change in the vibration state of the rear wheel output shaft 18, the relationship between the control signal of the control unit 53 and the engagement start point of the transfer clutch 17 is learned. It becomes possible. As a result, not only the responsiveness in controlling the torque distribution ratio of the front and rear wheels 21 and 24 can be improved, but also the torque distribution ratio of the front and rear wheels 21 and 24 can be controlled with high accuracy, and the vehicle running performance and traveling can be improved. Quality can be improved. In addition, learning control of the transfer clutch 17 is executed using signals output from existing sensors such as the steering angle sensor 55 and the rear wheel rotation sensor 57, so that the control system is simplified and the cost is reduced. It becomes possible to plan. Further, since the learning control for changing the fastening force of the transfer clutch 17 is executed in the low vehicle speed region and the low throttle opening region, it is possible to execute the learning control while ensuring safety. .

  7 and 8 are explanatory diagrams showing the relationship among the front wheel output shaft rotational speed Nf, the rear wheel output shaft rotational speed Nr, and the duty ratio Rd. FIGS. 7 and 8 show a situation from when the steering 54 is operated to shift from the straight traveling state to the turning traveling state, and after the steering 54 is returned to return from the turning traveling state to the straight traveling state. FIG. 7 shows a case where the normal control of the transfer clutch 17 is continued, and FIG. 8 shows a case where the learning control of the transfer clutch 17 is executed. The steering angle change rate Vsa shown in FIGS. 7 and 8 is the change rate of the steering angle Sa.

  First, as shown in FIG. 7, when the steering 54 is operated to shift from the straight traveling state to the turning traveling state, a rotational difference is generated between the front wheel output shaft rotational speed Nf and the rear wheel output shaft rotational speed Nr. Further, in the turning traveling state, the transfer clutch 17 is controlled to slip in order to absorb the rotational difference between the front and rear wheels 21 and 24. At this time, the transfer clutch 17 is controlled according to the pulse frequency of the control signal. Stick-slip phenomenon occurs. The rear wheel output shaft 18, which has a smaller inertia force than the front wheel output shaft 16, generates vibration due to the occurrence of the stick-slip phenomenon, and the clutch output pressure control valve 52 depends on the rear wheel output shaft speed Nr. A vibration corresponding to the pulse frequency of the control signal for (appears α1). Further, when the steering wheel 54 is returned to return from the turning traveling state to the straight traveling state, the rotational difference between the front wheel output shaft rotational speed Nf and the rear wheel output shaft rotational speed Nr is eliminated. It is canceled (symbol β1).

  Next, a case where learning control is executed under the same traveling state as in FIG. 7 will be described. As shown in FIG. 8, when a vibration appears in the rear wheel output shaft rotation speed Nr under the turning traveling state in which the steering wheel 54 is operated (symbol α2), the reduction of the duty ratio Rd is started (symbol β2). ). When the vibration that appeared in the rear wheel output shaft speed Nr disappears by lowering the duty ratio Rd (reference γ2), the control unit 53 changes the duty ratio Rd (reference δ2) at that time to the transfer clutch 17 Learning is performed as the duty ratio Rd of the control signal corresponding to the fastening start point. As described above, after the learning control is completed, the normal control is restored, the duty ratio Rd is increased (reference ε2), and the transfer clutch 17 is controlled to the slip state. In this way, by learning the relationship between the control signal of the control unit 53 and the engagement start point of the transfer clutch 17, not only the responsiveness when controlling the torque distribution ratio of the front and rear wheels 21, 24 is increased, but also the front and rear Since the torque distribution ratio of the wheels 21 and 24 can be controlled with high accuracy, the running performance and running quality of the vehicle can be improved.

  It goes without saying that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention. For example, in the above description, by connecting the transfer clutch 17 to the rear wheel output shaft 18, the front wheel 21 functions as a main driving wheel and the rear wheel 24 functions as a sub driving wheel. However, by connecting the transfer clutch 17 to the front wheel output shaft 16, the front wheel 21 may function as a slave drive wheel, and the rear wheel 24 may function as a main drive wheel. In this case, it goes without saying that the front wheel output shaft 16 functions as a slave drive side output shaft and the rear wheel output shaft 18 functions as a main drive side output shaft.

  In the above description, the turning state of the vehicle is determined based on the steering angle Sa from the steering angle sensor 55. However, the present invention is not limited to this, and the front wheel output shaft rotational speed Nf and the rear wheel output shaft are not limited thereto. When the rotational speed difference from the rotational speed Nr exceeds a predetermined value, the turning traveling state may be determined, or the turning traveling state may be determined based on an output signal from the wheel speed sensor 58. Further, the turning state may be determined based on an output signal from the acceleration sensor.

1 is a skeleton diagram showing an automatic transmission of a four-wheel drive vehicle equipped with a drive system control device according to an embodiment of the present invention. FIG. It is sectional drawing which shows a transfer clutch and its vicinity. It is a block diagram which shows the control system of a transfer clutch. It is explanatory drawing which shows the turning driving state of a four-wheel drive vehicle. It is a flowchart which shows an example of the procedure of the learning permission determination which determines whether learning control is performed. It is a flowchart which shows an example of the procedure of learning control. It is explanatory drawing which shows the relationship between the front-wheel output-shaft rotational speed of normal control, a rear-wheel output-shaft rotational speed, and a duty ratio. It is explanatory drawing which shows the relationship between the front-wheel output-shaft rotational speed of a learning control, a rear-wheel output shaft rotational speed, and a duty ratio.

Explanation of symbols

11 Engine (drive source)
16 Front wheel output shaft (Main drive side output shaft)
17 Transfer clutch (hydraulic clutch)
18 Rear wheel output shaft (slave drive side output shaft)
21 Front wheel (main drive wheel)
24 rear wheels
44 Hydraulic oil chamber 52 Clutch pressure control valve (clutch control valve)
53 Control unit (clutch control means, vibration detection means, learning means)
54 Steering 55 Steering angle sensor 56 Front wheel rotation sensor (main drive side rotation sensor)
57 Rear wheel rotation sensor (slave drive side rotation sensor)

Claims (6)

A drive system controller that drives a main drive wheel and a slave drive wheel using a driving force output from a drive source,
A main drive side output shaft that is provided between the drive source and the main drive wheel and transmits a driving force to the main drive wheel;
A slave drive side output shaft that is provided between the drive source and the slave drive wheel and transmits a drive force to the slave drive wheel;
A hydraulic clutch that is provided between the drive source and the slave drive side output shaft and distributes the drive force to the slave drive wheels;
A clutch control valve that is connected to the hydraulic oil chamber of the hydraulic clutch and controls supply of hydraulic oil to the hydraulic oil chamber;
Clutch control means for outputting a control signal to the clutch control valve to control the fastening force of the hydraulic clutch;
Vibration detecting means for detecting whether or not a predetermined vibration is generated in the slave drive side output shaft based on the rotation state of the slave drive side output shaft;
Based on the change in the vibration state of the driven-side output shaft when the control signal from the clutch control means is changed under the turning traveling state, the clutch control means and the hydraulic clutch are started to be engaged. A drive system control device comprising learning means for learning a relationship with a point. The drive system control device according to claim 1,
The clutch control means outputs a control signal at a predetermined pulse frequency to the clutch control valve,
The vibration detection means calculates the vibration frequency of the slave drive side output shaft based on the rotation state of the slave drive side output shaft, and when the vibration frequency converges to a predetermined range set based on the pulse frequency, It is determined that predetermined vibration is generated in the slave drive side output shaft. The drive system control device according to claim 1 or 2,
When a predetermined vibration is generated in the driven drive side output shaft under the turning traveling state, the control signal of the clutch control means is changed to the clutch release side,
The learning means learns a control signal when a predetermined vibration disappears from the driven-side output shaft as a control signal corresponding to an engagement start point of the hydraulic clutch. In the drive system control device according to any one of claims 1 to 3,
When the predetermined vibration is not generated on the driven side output shaft under the turning traveling state, the control signal of the clutch control means is changed to the clutch engagement side,
The learning means learns a control signal when a predetermined vibration is generated on the slave drive side output shaft as a control signal corresponding to an engagement start point of the hydraulic clutch. In the drive system control device according to any one of claims 1 to 4,
A steering angle sensor for detecting the steering angle of the steering 54;
The drive unit control device, wherein the learning unit learns a relationship between a control signal of the clutch control unit and a fastening start point of the hydraulic clutch under a state in which a steering angle exceeds a predetermined value. In the drive system control device according to any one of claims 1 to 4,
A main drive side rotation sensor for detecting the rotation speed of the main drive side output shaft;
A slave drive side rotation sensor for detecting the rotational speed of the slave drive side output shaft;
The learning means has a control signal of the clutch control means and an engagement start point of the hydraulic clutch in a state where the rotational speed difference between the main drive side output shaft and the slave drive side output shaft exceeds a predetermined value. A drive system controller characterized by learning the relationship between

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