JP2008179267A - Control device of four-wheel drive vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To suppress vibration attributable to a slip of a driving wheel. <P>SOLUTION: A control device of a four-wheel drive 10 has a drive source 14 and a driving force transmission 16 for distributing the output of the drive source 14 to a main driving wheel axle 18 and a driven wheel axle 24, and the axle rotational speed ratio of the main driving wheel axle 18 to the driven wheel axle 24 is set to be a predetermined axle rotational speed ratio. The control device comprises a speed change means 28 provided on a driving force transmission system between the main driving wheel axle 18 and the driven wheel axle 24, a speed change ratio control means 36 for controlling the speed change ratio of the speed change means 28, and vibration detection means 32F, 32R for detecting the vibration generated by the periodic change of the axle rotational speed ratio or detecting the prediction of the vibration. The speed change ratio control means 36 executes the vibration suppression control of controlling the speed change ratio of the speed change means 28 so as to suppress the vibration when the vibration detection means 32F, 32R detect the vibration or its prediction. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a control device for a four-wheel drive vehicle, and belongs to a technical field of travel control for stabilizing the travel of the four-wheel drive vehicle.

  Conventionally, in a four-wheel drive vehicle, the rotation of the axle of the main drive wheel and the axle of the slave drive wheel so that the peripheral speeds (speeds in the tangential direction on the ground plane) of the main drive wheel and the slave drive wheel coincide. The speed ratio is set to a predetermined ratio. For example, when the diameter ratio of the main drive wheel and the sub drive wheel is A: B, the ratio of the rotational speeds of the main drive wheel axle and the sub drive wheel axle is maintained at B: A.

  However, structurally, even if the ratio of the rotational speeds of the main drive wheel axle and the sub drive wheel axle is maintained at a predetermined ratio, for example, either the main drive wheel or the sub drive wheel on a wet road surface or a frozen road surface. The ratio of the rotational speeds of the main drive wheel axle and the sub drive wheel axle may change periodically due to slipping, slipping at different timings, or slipping of each driving wheel at different amounts. is there.

  For example, when the main drive wheel slips and rotates at a higher rotational speed than when the main drive wheel does not slip, the axles that support the drive wheels are driven via the drive force transmission system including the drive force transmission shaft. Since it is connected, torque is transmitted from the axle supporting the slipped main drive wheels to the axle supporting the non-slip slave drive wheels, and the torque is accumulated. In order to release the torque, the axle supporting the non-slip driven wheel rotates to cause the driven wheel to slip. When the driven wheel slips, the torque is transmitted from the driven wheel axle to the main driving wheel axle, and the torque is accumulated. In order to release the torque, the main drive wheel axle rotates further, resulting in a greater slip of the main drive wheel. Thus, when slip occurs alternately between the main drive wheel and the slave drive wheel, for example, as shown in FIG. 3 (a), the ratio of the rotational speeds of the primary drive wheel axle and the slave drive wheel axle is periodic. Will change.

  In addition, when the ratio of the rotational speeds of the main drive wheel axle and the sub drive wheel axle changes periodically, the axle and the drive force transmission shaft vibrate. Specifically, the torque release axle and the drive force transmission shaft vibrate. There are things to do. The vibration may cause discomfort to the passenger.

  As a countermeasure, there is one described in Patent Document 1, for example. This is because the drive force transmission system between the main drive wheel axle and the slave drive wheel axle has a clutch whose engagement force can be changed, and when the slip occurs, the engagement force of the clutch is reduced to reduce the main drive wheel axle. The vibration is suppressed by releasing the drive connection between the driven wheel axle and the driven wheel axle.

Special table 2005-162007

  However, the one disclosed in Patent Document 1 releases the drive connection between the main drive wheel axle and the slave drive wheel axle when slipping occurs, in other words, the two-wheel drive state is established, and the traveling performance as a four-wheel drive car is achieved. Is damaged.

  Accordingly, it is an object of the present invention to provide a control device for a four-wheel drive vehicle that can suppress vibration caused by slippage of the drive wheels without impairing the traveling performance of the four-wheel drive vehicle.

  In order to solve the above-described problems, the invention according to claim 1 of the present application includes a drive source and a drive force transmission device that distributes the output of the drive source to the main drive wheel axle and the slave drive wheel axle. And a control device for a four-wheel drive vehicle in which the axle rotation speed ratio between the main drive wheel axle and the slave drive wheel axle is set to a predetermined axle rotation speed ratio. A speed change means provided in a driving force transmission system between the speed change means, a speed change ratio control means for controlling a speed change ratio of the speed change means, and a vibration caused by a periodic change in the axle rotation speed ratio, or Vibration detection means for detecting a sign, and the speed ratio control means controls the speed ratio of the speed change means so as to suppress the vibration when the vibration detection means detects the vibration or its sign. Vibration suppression control is executed.

  According to a second aspect of the present invention, in the control device for a four-wheel drive vehicle according to the first aspect, the accelerator operation detecting means for detecting the depression operation of the accelerator pedal, the main drive wheel axle, and the driven wheel axle. An axle rotation speed detection means for detecting a rotation speed, wherein the vibration detection means detects the depression operation of the accelerator pedal by the accelerator operation detection means, and the main drive wheel axle detected by the axle rotation speed detection means The difference between the rotational speed of the driven wheel axle and the rotational speed of the driven wheel axle is equal to or greater than a predetermined rotational speed, which is a sign of the vibration.

  Further, the invention according to claim 3 is the control device for a four-wheel drive vehicle according to claim 2, wherein the speed ratio control means is predetermined after the accelerator operation detecting means detects the depression operation of the accelerator pedal. The vibration suppression control is executed until the time elapses.

  Furthermore, the invention according to claim 4 is the control device for a four-wheel drive vehicle according to any one of claims 1 to 3, further comprising a gradient detecting means for detecting a gradient of the road surface, The control means executes the vibration suppression control based on a detection result of the gradient detection means.

  In addition, the invention according to claim 5 is the control device for a four-wheel drive vehicle according to any one of claims 1 to 4, further comprising a friction coefficient detecting means for detecting a friction coefficient of the road surface, The gear ratio control means performs the vibration suppression control when the friction coefficient detection means detects a friction coefficient equal to or less than a predetermined value.

  According to the first aspect of the present invention, the transmission means is provided in the driving force transmission system between the main driving wheel axle and the driven driving wheel axle. When vibration is caused by slip of the drive wheel, that is, when vibration occurs due to a periodic change in the rotational speed ratio between the main drive wheel axle and the slave drive wheel axle (or when the vibration is predicted), Vibration suppression control is performed to control the gear ratio of the transmission means so as to suppress the vibration. Thereby, the vibration which gives an unpleasant feeling to a passenger | crew is suppressed, without impairing the driveability of a four-wheel drive vehicle.

  According to the second aspect of the present invention, when the accelerator pedal is depressed and the difference between the rotation speed of the main drive wheel axle and the rotation speed of the slave drive wheel axle is equal to or greater than a predetermined rotation speed, the vibration is predicted. Yes. This distinguishes vibrations due to other reasons from vibrations caused by slipping of the drive wheels (vibrations caused by the periodic change in the axle rotation speed ratio between the main drive wheel axle and the slave drive wheel axle). The vibration suppression control described above can be executed without making a mistake.

  Further, according to the invention described in claim 3, the vibration suppression control described above is likely to cause slipping of the drive wheel that is the cause of vibration until a predetermined time elapses after the accelerator pedal is depressed. It is executed during the limited period. Thereby, there is no need to wait in vain for executing the vibration suppression control.

  Furthermore, according to the invention described in claim 4, the above-described vibration suppression control is executed based on the gradient of the road surface. That is, it is determined whether the main driving wheel or the secondary driving wheel of the four-wheel drive vehicle is loaded with the weight of the vehicle, and the driving wheel that is not loaded with weight is slipped compared to the driving wheel that is loaded with weight. Vibration suppression control is performed in consideration of the fact that it is easy to perform. This effectively suppresses vibration regardless of the road surface gradient.

  In addition, according to the invention described in claim 5, when the friction coefficient of the road surface is detected and the detected friction coefficient is equal to or less than a predetermined value, for example, when it is equal to or less than a value at which the drive wheel slips with high probability, The vibration suppression control described above is executed. Thereby, there is no need to wait in vain for executing the vibration suppression control.

  FIG. 1 schematically shows the configuration of a four-wheel drive vehicle equipped with a control device for a four-wheel drive vehicle according to an embodiment of the present invention.

  The vehicle denoted by reference numeral 10 in FIG. 1 is a four-wheel drive vehicle having front drive wheels 12F and rear drive wheels 12R. The four-wheel drive vehicle 10 includes an engine 14 as a drive source, a transmission 16 for shifting the output of the engine 10 and transmitting the output to the drive wheels 12F and 12R, and a driving force from the transmission 16 to the left and right front drive wheels 12F. A front wheel differential 20 that is transmitted via the axle 18, a transfer 22 that extracts the driving force that is transmitted to the rear driving wheel 12R, and a driving force from the transfer 22 is transmitted to the left and right rear driving wheels 12R via the axle 24. And a rear wheel differential 26. In this configuration, the front drive wheel 12F is the main drive wheel, and the rear drive wheel 12R is the slave drive wheel.

  Further, the transfer 22 and the rear wheel differential 26 are drivingly connected via a speed change mechanism 28. Specifically, the other end of the driving force transmission shaft 30 a whose one end is connected to the output shaft of the transfer 22 is connected to the input shaft of the transmission mechanism 28, and the driving force transmission whose one end is connected to the output shaft of the transmission mechanism 28. The other end of the shaft 30b is connected to the input shaft of the rear wheel differential 26.

  The speed change mechanism 28 is configured to be able to change the speed change ratio, that is, the rotation speed ratio of the driving force transmission shafts 30a and 30b. Normally, the speed change mechanism 28 is configured to maintain the speed ratio at a predetermined speed ratio, in other words, to maintain the rotational speed ratio of the driving force transmission shafts 30a and 30b at the predetermined speed ratio. . The predetermined gear ratio is a gear ratio at which the peripheral speed (speed in the tangential direction on the ground contact surface) is the same in each of the drive wheels 12F and 12R.

  This will be described with reference to FIG. FIG. 2 schematically shows the four-wheel drive vehicle 10 in operation. During traveling, the peripheral speed V must naturally be the same in each of the drive wheels 12F and 12R. At this time, for example, when the radius of the front drive wheel 12F is r1 and the radius of the rear drive wheel 12R is r2, which is different from r1, the rotational speed VF of the front axle 18 and the rotational speed VR of the rear axle 24 are The ratio must be r2: r1. For this purpose, the speed change mechanism 28 needs to maintain the speed ratio so that the ratio of the rotational speed V1 of the driving force transmission shaft 30a and the rotational speed V2 of the driving force transmission shaft 32b is r2: r1. That is, the predetermined gear ratio to be maintained is such a gear ratio that the driving speeds 12F and 12R have the same peripheral speed. When the front drive wheel 12F and the rear drive wheel 12R are the same, the predetermined gear ratio is set to 1: 1.

  However, when the transmission mechanism 28 maintains the transmission ratio at a predetermined transmission ratio, the rotational speed ratio VF: VR between the front axle 18 and the rear axle 24 is changed to a rotational speed ratio corresponding to the predetermined transmission ratio (within the scope of claims). (Hereinafter referred to as “predetermined rotational speed ratio”.) Even if r2: r1 is maintained, this rotational speed ratio may change.

  For example, when the four-wheel drive vehicle 10 starts on a wet or frozen road surface, either the front drive wheel 12F or the rear drive wheel 12R slips, each slips at a different timing, or each As the drive wheels slip by different amounts, the rotational speed ratio between the front axle 18 and the rear axle 24 may periodically change from a predetermined rotational speed ratio. That is, the rotational speed of the axle that supports the slipped drive wheel may be higher than when the drive wheel does not slip.

  When such a drive wheel slip occurs and the rotational speed ratio between the front axle 18 and the rear axle 24 changes different from a predetermined rotational speed ratio, the axles of the respective axles are the transfer 22, the driving force transmission shaft 30a, and the transmission 28. The drive force transmission shaft 30b and the rear wheel differential 26 are connected to each other via a drive force transmission system, so that the slip (large slip amount) is not slipped from the axle supporting the drive wheel (slip amount). The torque is transmitted to and accumulated on the axle that supports the drive wheels. When the torque is released, the axle and the drive force transmission shaft may vibrate. The vibration may cause discomfort to the passenger.

  In order to suppress the vibration caused by the slip of the drive wheel, as shown in FIG. 1, the four-wheel drive vehicle 10 includes a rotation speed sensor 32F that detects the rotation speed of the axle 18 that supports the front drive wheel 12F, Based on a rotational speed sensor 32R that detects the rotational speed of the axle 24 that supports the rear drive wheel 12R, an accelerator sensor 34 that detects that an accelerator pedal (not shown) has been depressed, and signals from these sensors. And a control device 36 for controlling the speed ratio of the speed change mechanism 28. The control device 36 may be incorporated in a control device that controls the lighting, the engine 14, and the like.

  The control device 36 detects the rotational speed ratio between the front axle 18 and the rear axle 24 based on signals from the rotational speed sensors 32F and 32R. The control device 36 is configured to detect vibration caused by slipping of the drive wheels by detecting the rotation speed ratio.

  For example, as shown in FIG. 3B, the control device 36 determines the rotational speed of the front axle (main drive wheel axle) 18 and the rear axle (slave drive wheel axle) based on signals from the rotational speed sensors 32F and 32R. ) When a difference from the rotational speed of 24 is detected and the difference is equal to or greater than a predetermined rotational speed ΔV and an accelerator operation of depressing the accelerator pedal is detected based on a signal from the accelerator sensor 34, driving It is configured to detect as a sign of vibration caused by wheel slip. The reason why the accelerator operation of depressing the accelerator pedal is included in the condition for determining the sign of vibration is that slip of the drive wheel is likely to occur when the accelerator pedal is depressed, that is, during acceleration of the vehicle, and the rotational speed of the front axle 18 and the rear If only the difference from the rotational speed of the side axle 24 is greater than or equal to a predetermined rotational speed difference ΔV, it is possible to mistake the vibration caused by a phenomenon other than the slip of the driving wheel as the vibration caused by the slip of the driving wheel. This is because the vibration caused by slipping of the drive wheels is distinguished from the vibration caused by other causes.

  For example, as shown in FIG. 3C, the control device 36 determines the rotational speed of the front axle (main drive wheel axle) 18 and the rear axle (slave drive wheel) based on signals from the rotational speed sensors 32F and 32R. (Axle) 24 is configured to detect when the rotational speed of the rotational speed of the shaft 24 has been reversed twice as vibration caused by slip of the drive wheel.

  Furthermore, the control device 36 is configured to execute vibration suppression control that suppresses the vibration when detecting the sign of the vibration caused by the slip of the driving wheel or the vibration.

  This will be specifically described with reference to FIG. For example, a situation where only the front drive wheel 12F slips (or a situation where the slip amount of the front drive wheel 12F is larger than the slip amount of the rear drive wheel 12R), in other words, the rotational speed ratio VF: VR between the front axle 18 and the axle 24 is Consider a situation where a predetermined rotation speed ratio r2: r1 is changed to r3 (r3> r2): r1.

  In such a situation, torque is transmitted from the front axle 18 toward the rear axle 24, and torque is accumulated on the rear axle 24 and the driving force transmission shaft 30b on the rear wheel side. When this torque is released, the rear axle 24 and the driving force transmission shaft 30b may vibrate.

  As a countermeasure, when the control device 36 is in a situation where only the front drive wheel 12F slips (or a situation where the slip amount of the front drive wheel 12F is larger than the slip amount of the rear drive wheel 12R), the rear drive wheel is driven. The speed ratio of the speed change mechanism 28 is controlled so that the rotational speed VR of the rear axle 24 that supports the wheel 12R is increased (hereinafter, this control is referred to as “speed increase control”). That is, the speed ratio of the speed change mechanism 28 is controlled so that the rotational speed ratio VF: VR between the front axle 18 and the rear axle 24 that satisfies r3 (r3> r2): r1 approaches r2: r1. (See FIG. 3 (b) and FIG. 3 (c)). Thereby, it is possible to suppress the torque from being accumulated in the rear axle 24 and the driving force transmission shaft 30b on the rear wheel side, and thereby the vibration of the rear axle 24 and the driving force transmission shaft 30b that occurs when the torque is released. Is suppressed.

  On the other hand, the situation where only the rear drive wheel 12R slips (or the situation where the slip amount of the front drive wheel 12F) is smaller than the slip amount of the rear drive wheel 12R), in other words, the rotational speed of the front axle 18 and the rear axle 24. Consider a situation where the ratio VF: VR is changed from a predetermined rotational speed ratio r2: r1 to r2: r4 (r4> r1).

  In such a situation, torque is transmitted from the rear axle 24 toward the front axle 18, and torque is accumulated on the front axle 18 and the driving force transmission shaft 30a on the front wheel side. When this torque is released, the front axle 18 and the driving force transmission shaft 30ba may vibrate.

  As a countermeasure, when the control device 36 is in a situation where only the rear drive wheel 12R is slipped (or a situation where the slip amount of the front drive wheel 12F is smaller than the slip amount of the rear drive wheel 12R), The speed ratio of the speed change mechanism 28 is controlled so that the rotational speed VR of the rear axle 24 that supports the drive wheels 12R is lowered (hereinafter, this control is referred to as “deceleration control”). That is, the speed ratio of the speed change mechanism 28 is controlled so that the rotational speed ratio VF: VR between the front axle 18 and the rear axle 24 that satisfies r2: r4 (r4> r1) approaches r2: r1. Yes. Thereby, it is possible to suppress the torque from being accumulated in the front axle 18 and the driving force transmission shaft 30a on the front wheel side, thereby suppressing the vibration of the front axle 18 and the driving force transmission shaft 30a that occurs when the torque is released. ing.

  In summary, when the control device 36 detects either of the above two situations, the control device 36 executes the control for suppressing the vibration generated by executing either the acceleration control or the deceleration control, that is, the vibration suppression control. The vibration prevents the passenger from feeling uncomfortable. This is performed without impairing the running performance of the four-wheel drive vehicle.

  From here, the flow of an example of the control including the vibration suppression control for suppressing the vibration caused by the slip of the drive wheel performed by the control device 36 will be described with reference to FIG.

  FIG. 4 shows a flow showing an exemplary flow of control including vibration suppression control surrounded by a dotted line.

  First, in S110, the control device 36 reads a signal from the accelerator sensor 34 and determines whether or not the accelerator pedal is depressed. If it is detected that the accelerator pedal is depressed, the process proceeds to S120.

  In S120, the control device 36 starts reading signals from the rotation speed sensors 32F and 32R. Thereafter, the signal is continuously read (that is, the rotational speeds of the front axle 18 and the rear axle 24 are monitored).

  In S130, based on the signals from the rotation speed sensors 32F and 32R, the control device 36 indicates a sign of vibration as described above (the difference between the rotation speed of the front axle 18 and the rotation speed of the rear axle 24 is greater than or equal to ΔV. It is determined whether or not there is. If a vibration sign is detected, the process proceeds to S150 to start vibration suppression control. If no sign of vibration is detected, the process proceeds to S140.

  In S140, the control device 36, based on the signals from the rotational speed sensors 32F and 32R, causes the vibration described above (the rotational speed of the front axle 18 and the rotational speed of the rear axle 24 have been reversed twice. It is determined whether or not there is. If vibration is detected, the process proceeds to S150 to start vibration suppression control. If no vibration is detected, the control indicated by the flow is terminated.

  In S150, based on the signals from the rotational speed sensors 32F and 32R, the controller 36 determines whether the rotational speed ratio VF: VR between the front axle 18 and the rear axle 24 is the same as the predetermined rotational speed ratio r2: r1. Determine whether or not. If they are the same, the process proceeds to S160. Otherwise, the process proceeds to S170.

  In S160, the control device 36 determines whether or not a predetermined time has elapsed since the accelerator pedal was depressed. Here, the “predetermined time” refers to the time from when the accelerator pedal is depressed until the rotational speed of the front axle 18 or the rear axle 24 reaches a rotational speed corresponding to the amount of depression of the accelerator pedal. In other words, the predetermined time is the time required for the acceleration to end. If the predetermined time has not elapsed, the process returns to S150 to continue the vibration suppression control. When the predetermined time has passed, the control shown in the flow is ended because the acceleration is not finished and the driving wheel is unlikely to slip.

  On the other hand, if it is determined in S150 that the rotational speed ratio VF: VR of the front axle 18 and the rear axle 24 is not the same as the predetermined rotational speed ratio r2: r1, the controller 36 in S170, the rotational speed ratio VF: It is determined whether VR is r3 (r3> r2): r1. When the rotation speed ratio VF: VR is r3 (r3> r2): r1, the process proceeds to S180. Otherwise, the process proceeds to S190.

  In S180, the control device 36 executes the above-described speed increase control. That is, by controlling the speed ratio of the speed change mechanism 28, the rotational speed VR of the rear axle 24 is increased so that the rotational speed ratio VF: VR between the front axle 18 and the rear axle 24 is a predetermined rotational speed ratio r2: Approach to r1. And in order to confirm that it has approached, it returns to S150.

  On the other hand, if it is determined in S170 that the rotational speed ratio VF: VR of the front axle 18 and the rear axle 24 is not the rotational speed ratio r3 (r3> r2): r1, that is, r2: r4 (r4> r1). In this case, in S190, the control device 36 executes the above-described deceleration control. That is, by controlling the transmission ratio of the transmission mechanism 28, the rotational speed VR of the rear axle 24 is decelerated, so that the rotational speed ratio VF: VR between the front axle 18 and the rear axle 24 is a predetermined rotational speed ratio r2: r1. To get closer to. And in order to confirm that it has approached, it returns to S150.

  According to the control shown in this flow, the rotation speed ratio VF between the front axle 18 and the rear axle 24 is long from the time when the driving wheel is easily slipped, until the predetermined time has elapsed since the accelerator pedal was depressed (during acceleration): VR is substantially maintained at a predetermined rotational speed ratio r2: r1.

  While the present invention has been described with reference to the above-described embodiment, the present invention is not limited to this.

  For example, according to the above-described embodiment, the vibration suppression control that suppresses the vibration due to the slip of the drive wheel is executed from when the accelerator pedal is depressed until a predetermined time elapses, that is, during acceleration. You may make it perform in addition to inside. In this case, for example, it is possible to cope with a case where the drive wheel slips due to water accumulation on the road surface while traveling at a constant speed.

  Further, since the likelihood of the drive wheel slipping varies depending on the road surface gradient, vibration suppression control corresponding to the road surface gradient may be executed. That is, it is determined whether the main driving wheel or the secondary driving wheel of the four-wheel drive vehicle is loaded with the weight of the vehicle, and the driving wheel that is not loaded with weight is slipped compared to the driving wheel that is loaded with weight. Vibration suppression control may be performed in consideration of the fact that it is easy to do.

  For example, in a four-wheel drive vehicle that is climbing up, the weight of the vehicle is loaded on the rear wheels, and the front wheels are more likely to slip than the rear wheels. If the front wheel slips in this state, the rotational speed of the rear axle is increased via the speed change mechanism compared to when the front wheel is not slipping. The rear axle is not at the required rotational speed. Therefore, it is necessary to control the speed ratio of the speed change mechanism so that the speed increase amount corresponds to the gradient.

  The gradient of the road surface can be obtained from, for example, road information of a car navigation system, or can be known from a sensor that detects the inclination of the traveling direction of a four-wheel drive vehicle.

  Thus, by executing the vibration suppression control corresponding to the road surface gradient, the vibration caused by the slip of the drive wheel is effectively suppressed regardless of the road surface gradient.

  Furthermore, since the likelihood of drive wheel slippage also varies depending on the friction coefficient of the road surface, vibration suppression control is executed only when the friction coefficient of the road surface is less than a value that causes drive wheel slip, for example, with a high probability. May be.

  The friction coefficient that easily slips can be experimentally obtained, and the friction coefficient of the road surface can be roughly estimated from a plurality of information such as road information, outside temperature, and outside humidity of the car navigation system. In order to know the outside air temperature and the outside air humidity, a temperature sensor and a humidity sensor may be provided. As a result, the opportunity to execute the vibration suppression control is limited, and therefore, there is no wasteful waiting so that the vibration suppression control can always be executed.

  Furthermore, in the above-described embodiment, the vibration suppressed by the vibration suppression control and the sign thereof are detected based on the rotational speeds of the front and rear drive wheel axles, but are not limited thereto. For example, a vibration sensor may be provided at a location of a four-wheel drive vehicle where vibration due to slip can be detected separately from vibration due to other reasons, and vibration suppression control may be executed based on a signal from the vibration sensor.

1 is a diagram schematically showing a configuration of a four-wheel drive vehicle including a control device for a four-wheel drive vehicle according to an embodiment of the present invention. FIG. 1 is a perspective view schematically showing a four-wheel drive vehicle that is running. FIG. FIG. 6 is a diagram showing changes in the rotational speed of a main drive wheel axle and the rotational speed of a slave drive wheel axle when a vibration sign is detected and vibration suppression control is executed. It is a figure which shows an example of the control including vibration suppression control.

Explanation of symbols

10 Four-wheel drive vehicle 14 Drive source (engine)
16 Driving force transmission device (transmission)
18 Main drive wheel axle (front axle)
24 Sub-wheel axle (rear axle)
28 Transmission means (transmission mechanism)
32F, 32R Vibration detection means (rotational speed sensor)
36 Gear ratio control means (control device)

Claims (5)

A drive source and a driving force transmission device that distributes the output of the drive source to the main drive wheel axle and the slave drive wheel axle, and the axle rotation speed ratio between the main drive wheel axle and the slave drive wheel axle is predetermined. A control device for a four-wheel drive vehicle set to an axle rotation speed ratio,
Transmission means provided in a driving force transmission system between the main drive wheel axle and the slave drive wheel axle;
Transmission ratio control means for controlling the transmission ratio of the transmission means;
Vibration detection means for detecting vibrations caused by periodically changing the axle rotation speed ratio or detecting a sign of the vibrations,
The gear ratio control means executes vibration suppression control for controlling a gear ratio of the transmission means so as to suppress the vibration when the vibration detection means detects the vibration or a sign thereof. Control device for wheel drive vehicle. The control device for a four-wheel drive vehicle according to claim 1,
An accelerator operation detecting means for detecting an accelerator pedal depression operation;
Axle rotation speed detecting means for detecting the rotation speed of the main drive wheel axle and the slave drive wheel axle,
The vibration detecting means detects the depression operation of the accelerator pedal by the accelerator operation detecting means, and the difference between the rotational speed of the main drive wheel axle detected by the axle rotational speed detection means and the rotational speed of the slave drive wheel axle is detected. A control device for a four-wheel drive vehicle, characterized in that the vibration is a sign of a predetermined rotational speed or more. The control device for a four-wheel drive vehicle according to claim 2,
The transmission ratio control means performs the vibration suppression control until a predetermined time elapses after the accelerator operation detection means detects the depression of the accelerator pedal. Control device. In the control apparatus of the four-wheel drive vehicle as described in any one of Claims 1-3,
Having a slope detecting means for detecting the slope of the road surface;
The control apparatus for a four-wheel drive vehicle, wherein the gear ratio control means executes the vibration suppression control based on a detection result of the gradient detection means. In the control apparatus of the four-wheel drive vehicle as described in any one of Claims 1-4,
Having a friction coefficient detecting means for detecting a friction coefficient of the road surface;
The control apparatus for a four-wheel drive vehicle, wherein the gear ratio control means executes the vibration suppression control when the friction coefficient detection means detects a friction coefficient equal to or less than a predetermined value.

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