JP5245732B2 - Transfer device - Google Patents

Description

  The present invention controls a clutch engaging operation and a disengaging operation that are interposed between a two-wheel drive system and a four-wheel drive system using an actuator, thereby enabling a transfer to one of the drive systems. It relates to the device.

As a conventional transfer device, for example, there is a device that can be switched to either a two-wheel drive system or a four-wheel drive system by controlling the engagement capacity of a clutch with an electric motor (motor). 1).
Japanese Patent Laid-Open No. 07-304344

  However, in the conventional transfer device, since the time change rate of the fastening capacity is constant, the time change rate has been set to a large value in order to cope with any traveling state. For this reason, in the conventional transfer device, the drive system can be switched quickly for every traveling state, but on the motor itself or a power transmission system (for example, a power transmission gear set) from the motor to the clutch. Unnecessary loads may be applied, and there is room for improvement in terms of durability.

  In particular, in a rocky place, the wheel slips and slips when the wheel leaves the road surface for a moment, but if the wheel comes in contact with the ground, it may not slip. May not occur. That is, while traveling on a road surface such as a dirt, gravel road surface, or rocky place, the wheel may repeat a slip state and a non-slip state in a short time.

  In such a case, since a complicated switching request is made between the two-wheel drive system and the four-wheel drive system, if the rate of change of the fastening capacity with time is constant, the time when the electric motor makes a large change in the fastening capacity every time the switch is requested It is controlled by rate, ie, high responsiveness. That is, in the conventional transfer device, when a wheel repeats a slip state and a non-slip state in a short time, fluctuation (power change) in the motor becomes large. Since the load on the transmission system becomes larger, the necessity for improvement is particularly high.

  An object of the present invention is to provide a transfer device having a power transmission system with excellent durability.

  In the transfer device of the present invention, the clutch interposed between the two-wheel drive system and the four-wheel drive system is fastened to switch the clutch via the actuator when switching from the two-wheel drive system to the four-wheel drive system. The rate of time change when controlling the fastening capacity is made variable according to the traveling state.

  In the present invention, when switching from a two-wheel drive system to a four-wheel drive system, the time change rate of the engagement capacity command value is made variable according to the traveling state, so that the operation (responsiveness) of the actuator is also appropriate according to the traveling state. Can be controlled. For this reason, even in a traveling state in which switching between the two-wheel drive system and the four-wheel drive system frequently occurs during traveling, the load in the actuator can be kept small.

In the transfer device of the present invention, the clutch interposed between the two-wheel drive system and the four-wheel drive system is fastened to switch the clutch via the actuator when switching from the two-wheel drive system to the four-wheel drive system. The rate of time change when controlling the fastening capacity is reduced as the vehicle speed increases .

  Hereinafter, a transfer device according to the present invention will be described with reference to the drawings.

  FIG. 1 is a system diagram schematically showing a transfer device for an FR vehicle, which is an embodiment of the present invention.

  In FIG. 1, reference numeral 1 denotes an input shaft to which driving force from an engine or the like is input via an automatic transmission (not shown) or the like. Reference numeral 2 denotes an output shaft for a rear wheel that is integrally connected to the input shaft 1 and rotates together with the input shaft 1.

  Reference numeral 3 denotes a wet multi-plate drum clutch (hereinafter referred to as “clutch”). Reference numeral 3 a denotes a clutch drum that is integrally connected to the rear-wheel output shaft 2. Reference numeral 3b denotes a clutch hub that is rotatably supported with respect to the input shaft 1 penetrating the inside thereof.

Mutual the clutch drum 3a and the clutch hub 3b, a plurality of the drive-side plate C ₁ provided slidably relative to the clutch drum 3a, a plurality of driven-side plate C provided slidably relative to the clutch hub 3b _{The two} are related by arranging them alternately.

Further, reference numeral 3 c is a clutch piston that advances and retracts on the rear wheel output shaft 2 via the clutch drum 3 a and controls the engagement and release of the clutch 3. Clutch piston 3c is realized engagement of the clutch 3 by pressing the drive-side plate C _1, also to realize the release of the clutch 3 by releasing the pressing.

  Reference numeral 4 denotes a drive-side sprocket that is rotatably supported with respect to the clutch hub 3b that penetrates the inside thereof. Reference numeral 5 denotes, for example, a belt member formed of a plurality of chains and hung on the drive side sprocket 4. Reference numeral 6 denotes a driven-side sprocket that is drivingly coupled to the driving-side sprocket 4 via the belt member 5.

  Reference numeral 7 denotes a front wheel side output shaft to which the driven side sprocket 6 is integrally connected and is rotatable together with the driven side sprocket 6.

  Therefore, when the clutch 3 is released, a two-wheel drive (2WD) system in which the input from the input shaft 1 is output only from the rear wheel output shaft 2 is selected (hereinafter referred to as “2WD mode”). When engaged, a four-wheel drive (4WD) system is selected in which the input from the input shaft 1 is also output from the front wheel output shaft 7 together with the rear wheel output shaft 2 (hereinafter referred to as “4WD mode”).

  Reference numeral 10 denotes a motor as an actuator that controls engagement and disengagement of the clutch 3. The motor 10 is connected to the shaft 13 via the reduction gear sets 11 and 12, and causes the shaft 13 to rotate in synchronization with the rotation of the motor 10. Reference numeral 14 denotes a slider screwed to the shaft 13.

  The slider 14 is guided by a rail formed inside the guide member 15 fixed to the transfer case 20, so that the slider 14 advances and retreats in the shaft axial direction according to the rotation direction of the shaft 13. The clutch piston 3 c is integrally connected to the slider 14, and causes the clutch 3 to be engaged and released in synchronization with the advance and retreat of the slider 14.

  Reference numeral 30 denotes a controller equipped with a CPU and the like. The controller 30 includes, for example, a signal from the vehicle speed sensor 31, a signal from the front wheel output shaft rotational speed sensor 32, a signal from the rear wheel output shaft rotational speed sensor 33, a signal from the accelerator opening sensor 11, and a throttle opening sensor. Information necessary for determination of various running conditions such as a signal from 34 is input.

The controller 30 determines the traveling state using such input information as a material, determines the 2WD mode or the 4WD mode according to the traveling state or according to the driver's mode switching operation, and further selects the 4WD mode. In some cases, according to the flowchart shown in FIG. 2, an engagement capacity commanded as a target value when the clutch 3 is engaged (hereinafter referred to as “engagement capacity command value”) C _(o) is obtained, and then this engagement capacity command value C ₍ A time change rate (hereinafter referred to as “engagement capacity time change rate”) C _s according to _o) and a vehicle speed gain V _k corresponding to the vehicle body VSP are calculated.

That is, in this embodiment, while determining the time rate of change C _s in accordance with the torque capacity command value C _(o), we obtain the vehicle speed gain V _k corresponding to the vehicle speed VSP, vehicle speed gain V _k to the fastening capacity time rate C _s , The time change rate of the engagement capacity command value C _(o) when the clutch 3 is actually engaged via the motor 30 (hereinafter referred to as “command value time change rate”) C _{s (t)} Is determined. That is, in this embodiment, the controller 30 corresponds to the control means according to the present invention.

Therefore, the controller 30 first calculates the engagement capacity command value C _(o) required in the 4WD mode in step 101 of FIG. The engagement capacity command value C _(o) follows the driver's accelerator operation. For example, when the accelerator depression becomes large, the engagement capacity command value C _(o) also increases, and when the accelerator depression becomes small, the engagement capacity command value C _(o) increases. The value C _(o) also decreases. That is, in this embodiment, engagement capacity command value C _(o) is decreased when the input torque T _i to the clutch 3 increases, increases in proportion to, on the contrary, the input torque T _i to the clutch 3 is reduced To do.

After seeking engagement capacity command value C _(o) In step 1, the process proceeds to step 102, at step 102, by using a setting map shown in FIG. 3, the engagement capacity command value C _(o) Is determined, that is, the fastening capacity time change rate C _s is determined.

In this embodiment, the reference line for calculating the engagement capacity time change rate C _s is an area until the engagement capacity command value C _(o) becomes C _(o) = C _A as shown by the solid line in FIG. Assuming that the engagement capacity command value C _(o) is low, the constant time change rate (hereinafter referred to as “low capacity time change rate”) C _{s (Low)} = _Sa , but the engagement capacity command value C _(o) Increases in proportion to an increase in the engagement capacity command value C _(o) in a region from C _(o) = C _A to C _(o) = C _B. Then, in a region where engagement capacity command value C _(o) is C _(o) = or C _B, as the engagement capacity command value C _(o) is high, constant time rate of change (hereinafter, "high capacity time rate "referred to) C _{s (Hi)} = the S _b.

Therefore, for example, if the engagement capacity command value C _(o) calculated in step 101 is C _(o) = C _C , referring to FIG. 3, the engagement capacity time change rate C _s is expressed as C _s = S _c . According to the present invention, the increase in the above-mentioned reference line with C _A ≦ C _(o) ≦ C _B is not limited to being proportional to the engagement capacity command value C _(o) , You can increase it as you draw.

The controller 30 simultaneously detects the vehicle speed VSP from the vehicle speed sensor 31 in step 103, and then uses the setting map shown in FIG. 4 in step 104 to obtain the vehicle speed gain V _k corresponding to the vehicle speed VSP. Obtained based on vehicle speed VSP.

In the present embodiment, the reference line for calculating the vehicle speed gain V _k is a constant vehicle speed gain (hereinafter referred to as “the vehicle speed VSP”) until the vehicle speed VSP becomes VSP = V ₁ as shown by the solid line in FIG. V _{k (Hi)} = K _{1 (referred to as} “low vehicle speed gain”), but decreases in inverse proportion to the increase in the vehicle speed VSP until the vehicle speed VSP exceeds VSP = V ₁ and reaches VSP = V ₂ . When the vehicle speed VSP becomes equal to or higher than VSP = V ₂ , the vehicle speed VSP is assumed to be high, and a constant vehicle speed gain (hereinafter referred to as “high vehicle speed gain”) V _{k (Low)} = K ₂ .

Therefore, for example, if the vehicle speed VSP detected in step 103 is VSP = V ₃ , referring to FIG. 3, the vehicle speed gain V _k corresponding to the vehicle speed V ₃ becomes V _k = K ₃ . According to the present invention, the decrease of the calculation line when V ₁ ≦ VSP ≦ V ₂ is not limited to being inversely proportional to the vehicle speed VSP, but can be increased so as to draw a curve.

In step 105 of FIG. 2, the command value time change rate C when commanding the motor 30 is integrated by integrating the engagement capacity time change rate C _s calculated in step 102 and the vehicle speed gain V _k calculated in step 104. _{Find s (t)} . That is, in this embodiment, the integrated value (C _s × V _k ) becomes the command value time change rate C _{s (t)} .

As described above, in this embodiment, switching from the 2WD mode to the 4WD mode changes the engagement capacity command value C _(o) according to the input torque T _i (for example, by an accelerator operation) to the clutch 3, When the motor 10 is controlled with the target engagement capacity C in order to engage the clutch 3 with the engagement capacity command value C _(o) , the command value time change rate C _{s (t)} is the integrated value obtained in step 105. (C _s × V _k ).

That is, in the present embodiment, as shown in FIG. 5, in the region where the vehicle speed VSP is V ₁ or higher and the engagement capacity command value C _(o) is indicated by hatching with C _B or less, the engagement capacity time change rate C _s and the vehicle speed Since the gain V _k is variable, the command value time change rate C _{s (t)} is also variable in accordance with the engagement capacity time change rate C _s and the vehicle speed VSP. Since the engagement capacity time change rate C _s is a constant value of C _s = S _a or S _b and the vehicle speed gain V _k is K _s = K ₁ or K ₂ constant value, the command value time change rate C _{s (t )} Is also a constant value according to the engagement capacity command value C _(o) and the vehicle speed VSP.

As described above, when switching from the 2WD mode to the 4WD mode, according to the present invention, the time change rate of the engagement capacity C of the clutch 3, that is, the command value time change rate C _{s (t)} is set to the input torque T to the clutch 3. If it is variable according to the traveling state such as _i or the vehicle speed VSP, the operation (responsiveness) of the motor 10 can be controlled to an appropriate one according to the traveling state. For this reason, even in a traveling state in which switching between the 2WD mode and the 4WD mode frequently occurs during traveling, the load in the motor 10 can be kept small.

  That is, according to the present invention, an unnecessary load applied to the motor 10 is suppressed regardless of the traveling state when switching from the 2WD mode to the 4WD mode, and a power transmission system from the motor 10 to the clutch 3 (for example, Since unnecessary loads on the reduction gears 11 and 12) are also suppressed, a transfer device having a power transmission system with excellent durability can be provided. Note that, according to the transfer device according to the present invention, as described above, the load applied to the power transmission system is reduced, so that it is possible to employ a reduction gear made of resin that could not be used conventionally.

In particular, in this embodiment, the engagement capacity command value C _(o) increases in response to the depression of the accelerator. Therefore, the input torque T _i to the clutch 3 is used as a material for determining the running state for the operation, as shown in FIG. In addition, when the input torque _Ti is small, the command value time change rate Cs _(t) is set to be smaller than when the input torque _Ti is large.

In this case, if the accelerator pedal is weak and the accelerator opening APO is low and the wheel repeats a slip state and a non-slip state in a short time, it will be a Since the value time change rate C _{s (t)} becomes small, it is effective in suppressing the load applied to the motor 10 and the power transmission system from the motor 10 to the clutch 3. That is, this configuration is effective for improving the durability of the transfer device.

In the present invention, the extent deemed input torque T _i is small, for example, as a range in which the input torque T _i is given in the range of less than 200 N, also, it is determined that the input torque T _i is greater For example, a range in which the input torque T _i is 300 N or more can be mentioned. However, the above range is an exemplification, and the range is a range that can be appropriately changed according to the vehicle type, the preference of the driving vehicle, and the like.

Further, in the present embodiment, the vehicle speed VSP is used as a material for determining the running state. As shown in FIG. 4, when the vehicle speed VSP is high, the command value time change rate C _{s (t)} is higher than when the vehicle speed VSP is low. Is set to be smaller.

In this case, since the command value time change rate C _{s (t)} increases in a high vehicle speed range where switching between the 2WD mode and the 4WD mode is unnecessary, the phenomenon that the output torque from the transfer device changes excessively can be suppressed. Therefore, it is effective for suppressing the load applied to the motor 10 and the power transmission system from the motor 10 to the clutch 3. That is, this configuration is also effective for improving the durability of the transfer device.

  In the present invention, the range in which the vehicle speed VSP is determined to be low includes, for example, a range in which the vehicle speed VSP is less than 100 [km / h], and the range in which the vehicle speed VSP is determined to be high. For example, a range in which the vehicle speed VSP is 120 [km / h] or more can be mentioned. However, the above range is also an example, and the range is a range that can be appropriately changed according to the type of vehicle, the preference of the driving vehicle, and the like.

6 (a) and 6 (b) respectively show the command torque when the command value time change rate C _{s (t)} is changed according to the engagement capacity command value C _(o) and the vehicle speed VSP according to the present invention, It is the graph which monitored the command torque at the time of making it constant like.

If the engagement capacity time change rate C _s changes frequently during traveling at a low accelerator opening, such as traveling in a dirt, etc., this results in lowering the durability reliability of the motor. The durability reliability mentioned here includes, for example, a reduction gear (FIG. 1) caused by wear of a motor brush or a commutator caused by intermittently applying a voltage to the motor, or by intermittent load application at a low cycle. The durability reliability with respect to the acceleration of the deterioration of the transfer device (see reference numerals 11 and 12) is mentioned, and the durability of the transfer device is greatly affected.

On the other hand, as apparent from comparing FIGS. 6 (a) and 6 (b), the command value time change rate C _{s (t)} is made variable according to the fastening capacity C and the vehicle speed VSP in accordance with the present invention. When the value time change rate C _{s (t)} is reduced (FIG. 6 (a): present invention), when the command value time change rate C _{s (t)} is constant (FIG. 6 (b): conventional) Compared to the command torque, the frequency is low.

That is, if the command value time change rate C _{s (t)} is made variable in accordance with the engagement capacity C and the vehicle speed VSP according to the present invention, the running state is such that the switching between the 2WD mode and the 4WD mode occurs frequently. It is clear that the command torque can be reduced, and as a result, the load on the motor 10 and the load on the power transmission system such as a reduction gear connected to the motor 10 can be reduced.

The above is a preferred embodiment of the present invention, but various modifications can be made within the scope of the claims. For example, the information to be employed in the determination of the traveling state in accordance with the vehicle speed VSP, is not limited to the input torque T _i to the clutch, the accelerator opening (throttle opening), the rear wheel output shaft rotational speed (FF In a car, various information such as the front wheel output shaft speed), engine speed, road surface condition, and the like are included. Further, the vehicle speed VSP can be calculated from other rotational speeds such as the rear wheel output shaft rotational speed without using a vehicle speed sensor.

1 is a system diagram schematically showing a transfer device for an FR vehicle according to an embodiment of the present invention. It is a flowchart explaining the control which concerns on the same form. It is a setting map for determining the fastening capacity time change rate which concerns on the same form. It is a setting map for determining the command value time change rate which concerns on the same form. It is a map which shows the area | region which aims at the control which concerns on the same form. (a) and (b), respectively, monitored the command torque when the command value time change rate was changed according to the fastening capacity and the vehicle speed according to the present invention, and the command torque when it was made constant as in the prior art. It is a graph.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Input shaft 2 Output shaft for rear wheels 3 Drum clutch 3a Clutch drum 3b Clutch hub 3c Clutch piston 4 Drive side sprocket 5 Belt member 6 Drive side sprocket 7 Output shaft for front wheel
10 Motor (actuator)
11,12 Reduction gear
13 Shaft
14 Slider
16 Lever
30 controller
31 Vehicle speed sensor
32 Front wheel output shaft speed sensor
33 Rear wheel output shaft speed sensor
34 Accelerator position sensor
35 Throttle opening sensor

Claims (2)

A clutch that is interposed at a branch portion between the two-wheel drive system and the four-wheel drive system, and can be switched to one of the drive systems by fastening and releasing;
An actuator for controlling the engagement operation and the release operation of the clutch;
Control means for controlling the actuator so that the clutch is engaged with the engagement capacity command value;
The transfer device is characterized in that, when switching from two-wheel drive to four-wheel drive, the time rate of change of the engagement capacity command value decreases as the vehicle speed increases.   2. The transfer device according to claim 1, wherein the control means makes the rate of time change smaller when the input torque is small than when the input torque is large.

Images