JP2004189067A - Driving force controller for four-wheel drive vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a driving force controller for a four-wheel drive vehicle capable of making command torque agree with output torque even if clutch means difference rotation and clutch means temperature are changed. <P>SOLUTION: This driving force controller for the four-wheel drive vehicle controls driving force distributed to a pair of auxiliary driving wheels by changing tightening force of a clutch means. Target tightening force of the clutch means is compensated by a tightening force compensation unit based on difference rotation of the clutch means detected by a difference rotation detection unit and clutch means temperature. The controller controls the clutch means based on the compensated target tightening force. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a driving force control device for a four-wheel drive vehicle.
[0002]
[Prior art]
The driving force distribution device between the front and rear wheels and the left and right wheels using an electromagnetic clutch includes a pair of clutch mechanisms each including an electromagnetic coil, an armature, a piston, a clutch disc and a clutch plate, and each of the clutch mechanisms is a main driving mechanism. It is installed between the axle and the left axle of the auxiliary drive wheel and between the main drive axle and the right axle of the auxiliary drive wheel.
[0003]
The operating principle of this clutch mechanism is as follows. That is, the current value flowing through the left and right electromagnetic coils is controlled according to the driving state of the vehicle. The armature is attracted to the electromagnetic coil side according to the current flowing through the electromagnetic coil, and a thrust is generated. By this thrust, the piston integrally coupled with the armature presses the clutch, and the clutch disc and the clutch plate engage with each other to generate torque.
[0004]
This torque is transmitted to the left and right rear axles via the planetary gear set. By making the current applied to the electromagnetic coil variable, the output torque to the left and right rear axles can be variably controlled.
[0005]
The conventional driving force distribution device between the main driving wheel and the sub driving wheel or between the sub driving wheel pairs changes the current flowing through the left or right electromagnetic coil while keeping the input rotation of the clutch mechanism constant and the left and right output rotations constant. Then, the output torque is measured, a map of the output torque and the current is created from the measurement result, and the required torque is converted into a current command value and supplied to the electromagnetic coil.
[0006]
[Problems to be solved by the invention]
However, in the driving force distribution device described above, since the input rotation of the clutch mechanism is fixed and the output rotation is also fixed, and the map of the output torque and the current is created, the clutch differential rotation which is the difference between the input rotation and the output rotation is calculated. It is constant.
[0007]
When such a control method is applied to an actual vehicle, it can be said that this control method is effective when the vehicle runs with a clutch differential rotation that matches or is similar to the created map. There is a problem that the command torque and the output torque do not match in a region where the condition and the map condition are significantly different.
[0008]
In the conventional output torque and current map described above, the clutch temperature at the time of measurement is constant. Therefore, when adopted in an actual vehicle, the command torque and the output torque do not match in a region where the clutch temperature condition and the map condition are different. Problem.
[0009]
JP-A-6-147236 discloses a clutch device capable of suppressing a change in output torque even when the friction coefficient of the clutch sliding portion changes.
[0010]
However, in the clutch device disclosed in this publication, a change in output torque of the clutch device due to a change over time is suppressed to a small value. Since the parameter of change is not included in the control object at all, there is a problem that it is difficult to accurately control the driving force according to the operating state.
[0011]
Accordingly, an object of the present invention is to provide a driving force control device for a four-wheel drive vehicle that can control an actual driving force to a target driving force even when the driving state changes.
[0012]
[Means for Solving the Problems]
According to the first aspect of the present invention, there is provided a main drive wheel pair, a sub drive wheel pair, and clutch means associated with the sub drive wheel pair, and the auxiliary drive is performed by changing a fastening force of the clutch means. A driving force control device for a four-wheel drive vehicle that controls a driving force to be distributed to a pair of wheels, wherein a target driving force to be distributed to the pair of auxiliary driving wheels is determined based on a driving state of the four-wheel drive vehicle. A first target engagement force calculating unit for calculating a target engagement force of the clutch unit with respect to a differential rotation detection unit for detecting a differential rotation between an input rotational speed and an output rotational speed of the clutch unit; and a temperature equivalent value of the clutch unit. The first target engagement force calculating means based on the differential rotation detected by the differential rotation detecting means and the clutch temperature equivalent value calculated by the clutch temperature calculating means. A first target engagement force correction unit that corrects the output target engagement force, and a first control unit that controls the clutch unit based on the target engagement force corrected by the first target engagement force correction unit. A driving force control device for a four-wheel drive vehicle, comprising:
[0013]
According to the driving force control device of the first aspect, the target engagement force of the clutch means with respect to the target driving force distributed to the auxiliary driving wheel pair can be accurately calculated in consideration of the characteristics of the clutch means, and the actual driving force can be calculated. The target driving force can be controlled.
[0014]
According to the second aspect of the present invention, the clutch means includes a left clutch means and a right clutch means provided in association with each of the auxiliary drive wheel pairs. The target engagement force calculation means, the target engagement force correction means, and the clutch control means control the left and right clutch means based on the calculation of the target engagement force, the correction of the target engagement force, and the corrected target engagement force for the left and right clutch means, respectively. I do.
[0015]
This makes it possible to accurately calculate the target engagement forces of the left and right clutch means with respect to the left and right target drive forces in consideration of the characteristics of the clutch means in accordance with the driving state. The force can be controlled.
[0016]
According to the third aspect of the present invention, a main drive system for transmitting the driving force from the drive source to the main drive wheel pair; and a speed increasing mechanism for increasing the rotational speed of the main drive system and transmitting the rotational speed to the sub drive wheel pair And a clutch means associated with the auxiliary drive wheel pair, and an auxiliary drive system for transmitting a driving force from the speed increasing mechanism to the auxiliary drive wheel pair; and changing a fastening force of the clutch means. A driving force control device for a four-wheel drive vehicle that controls a driving force distributed to the auxiliary drive wheel pair, wherein a target engagement force of the clutch means is calculated based on an operation state of the four-wheel drive vehicle. First target engagement force calculating means; differential rotation detecting means for detecting a differential rotation between the input rotational speed and output rotational speed of the clutch means; clutch temperature calculating means for calculating a temperature equivalent value of the clutch means; The difference rotation detected by the rotation detection means and the difference rotation First target engagement force correction means for correcting the target engagement force calculated by the first target engagement force calculation means based on the clutch temperature equivalent value calculated by the latch temperature calculation means; and the first target engagement force correction And a first clutch control means for controlling the clutch means based on the target engagement force corrected by the means.
[0017]
According to the driving force control device of the third aspect, a change in the driving force due to a change in the differential rotation of the clutch means, which occurs when the operation of the speed-increasing mechanism is switched between the operation (increased speed) and the stop (direct connection), is detected.
[0018]
Then, in order to reduce the change in the driving force, the target engagement force of the clutch means with respect to the target driving force is accurately calculated in consideration of the characteristics of the clutch means, and the actual driving force is controlled so as to match the target driving force. be able to.
[0019]
According to the invention described in claim 4, the clutch means includes a left clutch means and a right clutch means provided in association with each of the auxiliary drive wheel pairs. The target engagement force calculation means, the target engagement force correction means, and the clutch control means determine the target engagement force for each of the left clutch means and the right clutch means, correct the target engagement force, and Control the clutch means.
[0020]
Therefore, according to the driving state of the vehicle, the target engagement forces of the left and right clutch means with respect to the left and right target drive forces can be calculated with high accuracy in consideration of the characteristics of the clutch means. The target driving force can be controlled.
[0021]
The term clutch means used in the present specification and claims means not only a simple clutch but also a brake for fixing a sun gear with a carrier output of a ring gear input of a planetary gear set as disclosed in the embodiment of the invention. It also includes a configuration in which the driving force is amplified (speed is reduced) by changing the fastening force, and the driving force can be controlled.
[0022]
BEST MODE FOR CARRYING OUT THE INVENTION
Referring to FIG. 1, there is shown a schematic diagram of a power transmission system of a four-wheel drive vehicle based on a front engine front drive (FF) vehicle to which the driving force control device of the present invention is applied.
[0023]
It should be noted that the present invention is not limited to a 4WD vehicle based on an FF vehicle, but a 4WD vehicle based on a rear engine / rear drive (RR) vehicle or a 4WD vehicle based on a front engine / rear drive (FR) vehicle. Also, the present invention can be applied to a midship (MR) 4WD vehicle.
[0024]
As shown in FIG. 1, the power transmission system according to the present embodiment includes a front differential device 6 in which the power of an engine 2 disposed in front of the vehicle is transmitted from an output shaft 4 a of a transmission 4, and a power transmission from the front differential device 6. It mainly includes a speed increasing device (transmission) 10 to which power is transmitted via a propeller shaft 8 and a rear differential device 12 to which power from the speed increasing device 10 is transmitted.
[0025]
The front differential device 6 has a conventionally well-known structure, and transmits the power from the output shaft 4a of the transmission 4 to the left and right front wheel drive shafts 20 and 22 via the plurality of gears 14 and the output shafts 16 and 18 in the differential case 6a. The transmission causes the front wheels 21 and 23 to be driven.
[0026]
As will be described later, the rear differential device 12 includes a pair of planetary gear sets and a pair of electromagnetic actuators for controlling engagement of the multi-plate clutch mechanism, and controls the left and right rear wheel drive shafts by controlling the electromagnetic actuators. By transmitting the power to the rear wheels 24 and 26, the rear wheels 25 and 27 are driven.
[0027]
FIG. 2 is a cross-sectional view of the speed increasing device 10 and a rear differential device 12 disposed downstream of the speed increasing device 10. The speed increasing device 10 includes an input shaft 30 rotatably mounted in a casing 28 and an output shaft (hypoid pinion shaft) 32.
[0028]
The speed increasing device 10 further includes an oil pump assembly 34, a planetary carrier assembly 38, a (directly connected) clutch assembly 40, and a speed change brake 42.
[0029]
The detailed structure of the speed increasing device 10 is disclosed in Japanese Patent Application No. 2002-278836 of the earlier application of the present applicant, and the contents described in the earlier application are incorporated as “reference” in the present application. I do.
[0030]
The rear differential device 12 provided on the downstream side of the speed increasing device 10 has a hypoid pinion gear 44 formed at the tip of the hypoid pinion shaft 32.
[0031]
The hypoid pinion gear 44 meshes with the hypoid ring gear 48, and the power from the hypoid ring gear 48 is input to the ring gears of the pair of planetary gear sets 50A and 50B provided on the left and right.
[0032]
The sun gears of the planetary gear sets 50A and 50B are rotatably mounted around a left rear axle 24 and a right rear axle 26. The planetary carriers of the planetary gear sets 50A and 50B are fixed to the left rear axle 24 and the right rear axle 26. A planet gear carried on the planetary carrier meshes with the sun gear and the ring gear.
[0033]
The left and right planetary gear sets 50A and 50B are connected to a clutch mechanism 51 provided for variably controlling the torque of the sun gear. The clutch mechanism 51 includes a wet multi-plate clutch 52 and an electromagnetic actuator 56 that operates the multi-plate clutch 52.
[0034]
The clutch plate of the wet multi-plate clutch 52 is fixed to the casing 54, and the clutch disc is fixed to the sun gears of the planetary gear sets 50A and 50B.
[0035]
The electromagnetic actuator 56 includes a core (yoke) 58, an electromagnetic coil 60 inserted in the core 58, an armature 62, and a piston 64 connected to the armature 62.
[0036]
When a current is applied to the electromagnetic coil 60, the armature 62 is attracted to the core 58 by the coil 60, and a thrust is generated. By this thrust, the piston 64 integrally connected to the armature 62 presses the multi-plate clutch 52, so that a clutch torque is generated.
[0037]
As a result, the sun gears of the planetary gear sets 50A and 50B are fixed to the casing 54, respectively, and the driving force of the hypoid pinion shaft 32 is transmitted through the ring gears, the planet gears and the planet gears of the planetary gear sets 50A and 50B, and the left and right rear axles 24, 26.
[0038]
By making the current applied to the electromagnetic coil 60 variable, the output torque to the left and right rear axles 24 and 26 can be variably controlled.
[0039]
Hereinafter, the operation of the amplifying device 10 and the rear differential device 12 described above will be described.
[0040]
When the transmission brake 42 is off, the direct coupling clutch 40 is engaged by the urging force of a coil spring (not shown). Therefore, the input shaft 30 and the planetary carrier 39 of the planetary carrier assembly 38 are connected via the direct coupling clutch 40, and the input shaft 30 and the output shaft 32 rotate integrally.
[0041]
When the left and right electromagnetic coils 60 of the rear differential device 12 are off in this directly connected state, the respective multi-plate clutches 52 are not engaged, and the respective sun gears of the planetary gear sets 50A, 50B idle around the left and right rear axles 24, 26, respectively. I do.
[0042]
Therefore, the driving force (torque) of the hypoid pinion shaft 32 is not transmitted to the left and right rear axles 24 and 26 at all. In this case, no driving force is transmitted to the rear wheels 25 and 27, and all the driving force is directed to the front wheels 21 and 23 to enter the two-wheel drive mode.
[0043]
When a predetermined amount of current is applied to the left and right electromagnetic coils 60 and the left and right multi-plate clutches 52 are completely engaged via the piston 64, the sun gears of the planetary gear sets 50A and 50B are fixed to the casing 54, respectively. You.
[0044]
Therefore, the driving force of the hypoid pinion shaft 32 is transmitted to the left and right rear axles 24, 26 via the ring gears, planet gears, and planet carriers of the planetary gear sets 50A, 50B.
[0045]
Therefore, the driving force of the input shaft 30 is transmitted to the left and right rear axles 24, 26 as much as the wheels can transmit within the range of the set maximum driving force. As a result, the four-wheel drive vehicle enters the four-wheel drive mode and travels straight.
[0046]
On the other hand, when turning around a corner with a relatively small turning radius in a running state that requires a driving force on the outside of turning on the rear wheel side, hydraulic pressure is introduced into the hydraulic chamber of the shift brake 42 and the shift brake 42 is engaged. When the transmission brake 42 is engaged, the engagement of the direct coupling clutch 40 is released.
[0047]
Thereby, the planetary carrier 39 is fixed to the casing 28. Even in this state, the small-diameter pinion gear 41 and the large-diameter pinion gear 43 held in the planetary carrier 39 can rotate.
[0048]
In this state, the planetary carrier assembly 38 becomes a gear train having a certain speed ratio, and a speed change (increased speed) is established between the input shaft 30 and the output shaft (hypoid pinion shaft) 32.
[0049]
It is assumed that the output shaft (hypoid pinion shaft) 32 is in an increased speed state with respect to the input shaft 30 while the vehicle is turning left, for example. At this time, more current flows through the right electromagnetic coil 60 of the rear differential device 12 than with the left electromagnetic coil 60, and the right multi-plate clutch 52 is more strongly engaged than with the left.
[0050]
As a result, the driving force of the hypoid pinion shaft 32 is distributed more to the right rear axle 26, and the driving torque of the rear wheel on the outside of the turning can be made larger than the driving torque of the rear wheel on the inside of the turning. Can be improved.
[0051]
In this way, by controlling the value of the current flowing through the left and right electromagnetic coils 60, the driving force of the input shaft 30 is directly connected or the speed is increased by the speed increasing device 10 to arbitrarily supply the left and right rear axles 24 and 26. They can be distributed to realize optimal turning control and / or straight driving control.
[0052]
According to the present invention, the current value to be supplied to the left and right electromagnetic coils 60 is accurately calculated in accordance with the variation in the differential rotation of the multi-plate clutch 52 and the variation in the clutch temperature, and is thereby corrected in consideration of the characteristics of the clutch. This is a driving force control device that controls the actual driving force of the rear wheels 25 and 27 to the target driving force by engaging the multi-plate clutch 52 with the target engagement force. The configuration of the present invention will be described with reference to FIGS. Will be described in detail.
[0053]
Referring to FIG. 3, a block diagram of the driving force control device of the present invention is shown. First, the driving state of the four-wheel drive vehicle is detected based on the output of each sensor and the like, and the rear wheel right wheel speed, the rear wheel left wheel speed, the driving side rotation speed, the front wheel right wheel speed, and the front wheel left wheel speed are set to the clutch target. It is input to the fastening force calculation means 68.
[0054]
Further, parameters such as a steering angle, a lateral G, a throttle opening, and an engine speed are input to the clutch target engagement force calculating means 68.
[0055]
The clutch target engagement force calculating means 68 calculates a clutch target engagement force with respect to a target drive force to be distributed to a predetermined auxiliary drive wheel pair (rear wheel pair) based on the driving state of the vehicle represented by these parameters. calculate. Preferably, the target engagement force of the left clutch 52 and the right clutch 52 with respect to the driving force distributed to each of the rear wheel pairs 25 and 27 is calculated.
[0056]
The rear right wheel speed, the rear left wheel speed, and the driving side rotation speed are also input to the differential rotation detecting means 70, and the differential rotation detecting means 70 detects a differential rotation between the input rotation speed and the output rotation speed of the clutch 52. .
[0057]
The clutch temperature calculating means 72 calculates a clutch temperature equivalent value based on the friction material temperature of the clutch 52 or the cooling / lubricating fluid temperature.
[0058]
The target engagement force of the left and right clutches calculated by the clutch target engagement force calculation means 68, the differential rotation between the input rotation speed and the output rotation speed of the clutch 52 calculated by the differential rotation detection means 70, and the clutch temperature calculation means 72 Each of the clutch temperature equivalent values is input to the clutch target engagement force correcting means 74.
[0059]
The clutch target engagement force correction unit 74 calculates the target engagement calculated by the clutch target engagement force calculation unit based on the clutch differential rotation detected by the differential rotation detection unit 70 and the clutch temperature equivalent value calculated by the clutch temperature calculation unit. Correct the force. The details of this correction method will be described later in detail.
[0060]
Preferably, the clutch target engagement force correcting means 74 is based on the differential rotation of each of the left and right clutches detected by the differential rotation detecting means 70 and the clutch temperature equivalent value of each of the left and right clutches calculated by the clutch temperature calculating means 72. The target engagement force of each of the left and right clutches calculated by the clutch target engagement force calculation means 68 is corrected.
[0061]
This corrected target engagement force is input to the clutch control means 76, and the engagement force of the clutch 52 is appropriately controlled.
[0062]
FIG. 4 shows an outline of the control of the driving force control device of the embodiment of the present invention, and the control content of the embodiment of the present invention will be described in more detail with reference to FIG.
[0063]
First, at block 78, a command torque value for the right rear wheel is calculated by an electronic control unit (ECU) mounted on the vehicle, and at block 80, a command torque value for the left wheel is calculated.
[0064]
The block 82 is equivalent to the clutch target engagement force correcting means 74 in FIG. 3. Based on parameters such as a rear wheel right wheel speed, a rear wheel left wheel speed, a driving side rotation speed, and a clutch temperature, each of the left and right clutches And a clutch temperature equivalent value are calculated, and the left and right clutch correction coefficients are calculated.
[0065]
A flowchart for calculating the clutch correction coefficient is shown in FIG. First, in step S11, the rear wheel speed is acquired. That is, the right rear wheel speed and the left rear wheel speed are acquired.
[0066]
Next, the routine proceeds to step S12, where the driven rotation speed of the clutch 52 is calculated from the tire diameters and gear ratios of the rear wheels 25, 27. Next, at step S13, the driving side rotation speed of the clutch 52 is acquired. Next, the routine proceeds to step S14, where the ECU calculates the differential rotation between the input rotation speed and the output rotation speed of the clutch 52.
[0067]
In step S15, the clutch friction material or the cooling / lubricating fluid temperature is detected. Then, the process proceeds to step S16, and based on the clutch differential rotation calculated in step S14 and the clutch temperature detected in step S15, the process proceeds to step S15. The correction coefficient is searched for with reference to a map in which the clutch difference rotation speed and the correction coefficient are associated as shown in the figure.
[0068]
Referring to FIG. 4 again, the command torque value of the right rear wheel is multiplied by the clutch correction coefficient of the right rear wheel by the multiplier 84 to calculate the command torque correction value of the right rear wheel. The command torque correction value is converted into a current command value for the right rear wheel by a torque-current conversion map 86, and the current command value is supplied to the electromagnetic coil 60 of the right electromagnetic actuator 56.
[0069]
Similarly, the command torque value of the left rear wheel is multiplied by the clutch correction coefficient of the left rear wheel by the multiplier 88 to calculate the command torque correction value of the left rear wheel. This command torque correction value is converted into a current command value for the left rear wheel by the torque-current conversion map 90, and the current command value is supplied to the electromagnetic coil 60 of the left electromagnetic actuator 56.
[0070]
The armature 62 is attracted to the core 58 by the coil 60 according to the current command value supplied to the electromagnetic coil 60, and a thrust is generated. The piston 64, which is integrally connected to the armature 62, presses the multi-plate clutch 52 by this thrust, thereby generating a clutch torque.
[0071]
As a result, the sun gears of the planetary gear sets 50A and 50B are respectively incompletely or completely fixed to the casing 54, and the driving force of the hypoid pinion shaft 32 is transmitted via the ring gears, the planet gears and the planet carriers of the planetary gear sets 50A and 50B. The power is controlled and transmitted to the left and right rear axles 24, 26.
[0072]
In the present embodiment, by appropriately controlling the current applied to the electromagnetic coil 60 according to the clutch differential rotation speed and the clutch temperature equivalent value, the target engagement force of the clutch 52 can be controlled according to the clutch characteristics. The actual driving force of the rear wheels 25, 27 can be controlled to the target driving force.
[0073]
The turning state of the vehicle is detected from the steering angle, the rotational speed difference between the left and right front wheels 21 and 23, the lateral G, and the like. Control.
[0074]
If necessary, the speed increasing device 10 is operated to increase the rotational speed of the output shaft (hypoid pinion shaft) 32 as compared with the rotational speed of the input shaft 30, thereby improving running stability.
[0075]
【The invention's effect】
According to the driving force control device of the first aspect, it is possible to accurately calculate the target engagement force of the clutch means with respect to the target driving force distributed to the sub-drive wheel pair in consideration of the characteristics of the clutch means. The target driving force can be controlled.
[0076]
According to the driving force control device of the second aspect, the target engagement force of the left and right clutch means with respect to the left and right target driving force can be accurately calculated in consideration of the characteristics of the clutch means, and the actual left and right driving force can be calculated. The target driving force can be controlled.
[0077]
According to the driving force control device of the third aspect, a change in the driving force due to a change in the differential rotation of the clutch means that occurs when the operation of the speed increasing mechanism is switched is detected, and the clutch for the target driving force is reduced in order to reduce the change in the driving force. The target engagement force of the means can be accurately calculated in consideration of the characteristics of the clutch means, and the actual driving force can be controlled to match the target driving force.
[0078]
According to the driving force control device of the fourth aspect, it is possible to accurately calculate the target engagement forces of the left and right clutch means with respect to the left and right target driving forces in consideration of the characteristics of the clutch means in accordance with the driving state of the vehicle. Thus, the actual left and right driving forces can be controlled to the target driving force.
[Brief description of the drawings]
FIG. 1 is a schematic diagram showing a power transmission system of a four-wheel drive vehicle suitable for applying a driving force control device of the present invention.
FIG. 2 is a sectional view of a speed increasing device and a rear differential device to which the driving force control device of the present invention is applied.
FIG. 3 is a block diagram of a driving force control device according to the present invention.
FIG. 4 is an explanatory diagram showing an operation outline of the driving force control device of the present invention.
FIG. 5 is a flowchart for calculating a clutch correction coefficient.
FIG. 6 is a map showing a relationship between a clutch difference rotation speed and a correction coefficient according to a temperature change.
[Explanation of symbols]
10 speed increasing device 12 rear differential device 24,26 rear axle 28,54 casing 30 input shaft 32 output shaft (hypoid pinion shaft)
34 oil pump assembly 38 planetary carrier assembly 40 direct coupling clutch (direct coupling clutch assembly)
42 speed change brakes 50A, 50B planetary gear set 51 clutch mechanism 52 wet multi-plate clutch 56 electromagnetic actuator 58 core (yoke)
Reference Signs List 60 electromagnetic coil 62 armature 68 clutch target engagement force calculation means 70 differential rotation calculation means 72 clutch temperature calculation means 74 clutch target engagement force correction means 76 clutch control means

Claims (4)

A main driving wheel pair, a sub driving wheel pair, and clutch means associated with the sub driving wheel pair, and controlling a driving force distributed to the sub driving wheel pair by changing a fastening force of the clutch means. A driving force control device for a four-wheel drive vehicle,
A first target engagement force calculation unit configured to calculate a target engagement force of the clutch unit with respect to a predetermined target drive force to be distributed to the auxiliary drive wheel pair based on an operation state of the four-wheel drive vehicle;
Differential rotation detecting means for detecting a differential rotation between the input rotation speed and the output rotation speed of the clutch means,
Clutch temperature calculating means for calculating a temperature equivalent value of the clutch means,
A first target that corrects the target engagement force calculated by the first target engagement force calculation unit based on the differential rotation detected by the differential rotation detection unit and a clutch temperature equivalent value calculated by the clutch temperature calculation unit; Fastening force correction means,
First control means for controlling the clutch means based on the target engagement force corrected by the first target engagement force correction means;
A driving force control device for a four-wheel drive vehicle, comprising: The clutch means includes left clutch means and right clutch means provided in association with each of the auxiliary drive wheel pairs,
A second target engagement force for calculating a target engagement force of the left clutch unit and the right clutch unit with respect to a predetermined driving force distributed to each of the sub-drive wheel pairs based on an operation state of the four-wheel drive vehicle. Calculating means;
Based on the differential rotation of each of the left clutch unit and the right clutch unit detected by the differential rotation detection unit and the clutch temperature equivalent value of each of the left clutch unit and the right clutch unit calculated by the clutch temperature calculation unit. A second target engagement force correction unit that corrects the target engagement force of each of the left clutch unit and the right clutch unit calculated by the second target engagement force calculation unit;
2. The apparatus according to claim 1, further comprising a second clutch control unit that controls the left clutch unit and the right clutch unit based on the target engagement force corrected by the second target engagement force correction unit. Of four-wheel drive vehicle. A main driving system for transmitting a driving force from a driving source to a main driving wheel pair; a speed increasing mechanism for increasing a rotational speed of the main driving system and transmitting the rotation speed to a sub driving wheel pair; And a sub-drive system for transmitting the driving force from the speed increasing mechanism to the sub-drive wheel pair; and distributing to the sub-drive wheel pair by changing the fastening force of the clutch means. A driving force control device for a four-wheel drive vehicle that controls the driving force to be applied,
First target engagement force calculating means for calculating a target engagement force of the clutch means based on an operation state of the four-wheel drive vehicle;
Differential rotation detecting means for detecting a differential rotation between the input rotation speed and the output rotation speed of the clutch means,
Clutch temperature calculating means for calculating a temperature equivalent value of the clutch means,
A first target that corrects the target engagement force calculated by the first target engagement force calculation unit based on the differential rotation detected by the differential rotation detection unit and a clutch temperature equivalent value calculated by the clutch temperature calculation unit; Fastening force correction means,
First clutch control means for controlling the clutch means based on the target engagement force corrected by the first target engagement force correction means;
A driving force control device for a four-wheel drive vehicle, comprising: The clutch means includes left clutch means and right clutch means provided in association with each of the auxiliary drive wheel pairs,
A second target engagement force for calculating a target engagement force of the left clutch unit and the right clutch unit with respect to a predetermined driving force distributed to each of the sub-drive wheel pairs based on an operation state of the four-wheel drive vehicle. Calculating means;
Based on the differential rotation of each of the left clutch unit and the right clutch unit detected by the differential rotation detection unit and the clutch temperature equivalent value of each of the left clutch unit and the right clutch unit calculated by the clutch temperature calculation unit. A second target engagement force correction unit that corrects the target engagement force of each of the left clutch unit and the right clutch unit calculated by the second target engagement force calculation unit;
4. The apparatus according to claim 3, further comprising a second clutch control unit that controls the left clutch unit and the right clutch unit based on the target engagement force corrected by the second target engagement force correction unit. Of four-wheel drive vehicle.

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