JPH02189233A - Two-four selecting controller for four-wheel drive vehicle - Google Patents

Abstract

PURPOSE:To enable positive and speedy starting by controlling a 2-4 changing mechanism according to connectivity in a freewheel mechanism at time of engine starting, in such a one which provides the freewheel mechanism cutting a driving system at the driven wheel side at time of 2-wheel drive. CONSTITUTION:In this 4WD vehicle, front axles 15, 16 are connected to a first output shaft 11 of a transfer unit 10 with a built-in 2-4 changing mechanism via a propeller shaft 13 and a front-wheel differential gear 14, and rear axles are connected to a second output shaft 12 likewise. In addition, there is provided with a freewheel unit 50 which connects or disconnects power transmission to the front axle 16 on one side. In this case, when this freewheel device 50 is cut by a controller 60 in the case where an operating position of the 2-4 changing mechanism is in an intermediate position of a 2WD position and a 4WD position at time of engine starting, the 2-4 changing mechanism is controlled to operate it to the 2WD position and when the freewheel mechanism 50 is connected, it is controlled to be operated to the 4WD position, respectively.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a four-wheel drive vehicle, particularly a wheel that can be switched between a two-wheel drive state and a four-wheel drive state, and that is a driven wheel when the two-wheel drive is performed. The present invention relates to a 2-4 switching control device for a four-wheel drive vehicle equipped with a five-wheel mechanism for disconnecting a drive system.

(Prior Art) In a four-wheel drive vehicle in which the front wheels and rear wheels are driven by engine output, it is possible to switch to a two-wheel drive state in which only one of the front wheels or the rear wheels is driven by the driver's operation. In this case, for example, as described in Japanese Patent Application Laid-open No. 135320/1983,
A freewheel mechanism may be provided to disconnect the drive system of the driven wheel during two-wheel drive. In a transfer device that divides the output of the engine or transmission into the front wheels and the rear wheels, for example, when power transmission to the front wheels is cut off to create a two-wheel drive state, the front wheels become driven wheels. This is provided to prevent the drive system from the front wheel to the transfer device from being unnecessarily backdriven due to the rotation of the front wheels, thereby reducing drive loss.

On the other hand, when switching between the two-wheel drive state and the four-wheel drive state is enabled as described above, the switching mechanism may be configured to be operated by an actuator in order to improve the operability of the switching mechanism. In this case, the actuator is operated by the driver's switch operation, and the switching mechanism is set to the 4-wheel drive position where driving force is transmitted to both the front and rear wheels, and the transmission of driving force to either wheel is cut off. The vehicle is configured to be moved to and from a two-wheel drive position.

(Problem to be Solved by the Invention) By the way, in the case where the switching mechanism between two-wheel drive and four-wheel drive (hereinafter referred to as 2-4 switching mechanism) is operated by an actuator as described above, the actuator If the engine is stopped during the switching operation,
The actuator or switching mechanism may stop at an intermediate position between the two-wheel drive position and the four-wheel drive position. In this case, since this type of 4-wheel drive vehicle basically runs in 4-wheel drive mode, the actuator is operated so that the switching mechanism moves to the 4-wheel drive position when the engine is next started. , it is conceivable to configure the vehicle to start in a four-wheel drive state. However, in that case, if the freewheel mechanism that connects or disconnects the drive system of either the front wheels or the rear wheels is in the disconnected state, the freewheel mechanism will not be installed even if the switching mechanism is operated to the four-wheel drive state. This means that the driving force will not be transmitted to the wheels. In particular, if the transfer device is equipped with a center differential to allow for a difference in rotational speed between the front and rear wheels, the center differential is in a state where differential operation is possible and the freewheel mechanism is automatically disconnected. If this happens, driving force will not be transmitted to either the front or rear wheels, making it impossible to start the vehicle. In addition, one possible solution to this problem is to connect the freewheel mechanism described above and then operate the switching mechanism from the intermediate position to the four-wheel drive position. It will take some time before this becomes possible.

The present invention solves the above-mentioned problems in a four-wheel drive vehicle that is equipped with an actuator that operates a 2-4 switching mechanism and is also provided with a freewheel mechanism that disconnects the drive system of the driven wheel during two-wheel drive. The object of the present invention is to enable the vehicle to start reliably and quickly the next time it starts even if the switching mechanism or actuator stops between the two-wheel drive position and the four-wheel drive position. .

(Means for Solving the Problems) In order to solve the above problems, the present invention is characterized by having the following configuration.

That is, the 2-4 switching control device for a 4-wheel drive vehicle according to the present invention provides a 2-4 switching control device for driving only either the front wheels or the rear wheels.
A 2-4 switching mechanism that switches between a wheel drive state and a four-wheel drive state that drives front wheels and rear wheels, an actuator that operates the 2-4 switching mechanism, and a drive wheel that becomes a driven wheel when driving two wheels. In a four-wheel drive vehicle equipped with a freewheel mechanism for disconnecting the system, two
4. Operation position detection means for detecting the operation position of the switching mechanism;
a freewheel detection means for detecting a disconnected state of the freewheel mechanism, and when the operating position of the 2-4 switching mechanism by the actuator is at an intermediate position between a 2-wheel drive position and a 4-wheel drive position when the engine is started; and control means for operating the actuator in accordance with the outputs of both of the detection means. By this control means, in the above case, if the freewheel mechanism is disconnected, the 2-4 switching mechanism is set to the 2-wheel drive position, and if the freewheel mechanism is connected, the 2-4 switching mechanism is set to the 2-wheel drive position. The actuator is actuated to operate the wheel drive position.

(Function) According to the above configuration, if the engine is stopped while the 2-4 switching mechanism is operating and the actuator is stopped at an intermediate position between the 2-wheel drive position and the 4-wheel drive position of the mechanism, the next When starting the engine, if the freewheel mechanism is connected, the actuator will move to the 4-wheel drive position, allowing you to start in 4-wheel drive, and if the freewheel mechanism is disconnected, the actuator will move to the 4-wheel drive position. The system operates to the wheel drive position and becomes ready to start in two-wheel drive mode. In other words, even when the actuator is stopped at an intermediate position as described above, it is basically possible to start immediately in 4-wheel drive mode, and even when the freewheel mechanism is disconnected, it is possible to start immediately in 2-wheel drive mode. This makes it possible to start the vehicle reliably and quickly.

(Example) Examples of the present invention will be described below.

First, the general configuration of a four-wheel drive vehicle according to this embodiment and its M control system will be explained with reference to FIG.

This four-wheel drive vehicle is equipped with a transfer device 10 to which engine output is input via a transmission (not shown), and the device 10 has a first output shaft 11 that projects forward and a first output shaft 11 that projects rearward. A second output shaft 12 is provided. The first output shaft 11 reaches the front wheels via a propeller shaft 3, a front wheel differential 14, and left and right front axles 15 and 16. Although not shown, the second output shaft 12 also connects to a propeller shaft, It reaches the rear wheels via a rear wheel differential and left and right rear axles.

As described later, the transfer device 10 includes a sub-transmission 20, a center differential 30, and a center differential 30 as main components.
a switching device 40 (see FIG. 2.3), and
This transfer device 10 has a two-wheel drive mode in which the power from the sub-transmission 20 is transmitted only from the second output shaft 12 to the rear wheels, and a two-wheel drive state in which the power from the sub-transmission 20 is transmitted only to the rear wheels from the first and second output shafts 11 and 12 to the front and rear wheels. In the four-wheel drive state, the center differential 30 is operated differentially to allow a difference in rotational speed between the front and rear wheels. It is possible to switch between a free state and a center differential locked state in which the differential operation of the center differential is prevented and the front and rear wheels are equally driven, and these switches are performed by the switching device 40.

Further, the front wheel differential device 14 is provided with a freewheel device 50 that connects and disconnects the transmission of power to one front axle 16, and a negative pressure actuator 5 that drives the device 50.
1 is provided. This actuator 51 is connected to first and second negative pressure passages 52 and 53, and
A freewheel connection solenoid 54 and a disconnection solenoid 55 are arranged in these negative pressure passages 52 and 53, respectively, and when the connection solenoid 54 is ON and the disconnection solenoid 55 is OFF, the freewheel device 50 is connected. The freewheel device 50 is disconnected when the connection solenoid 54 is OFF and the disconnection solenoid 55 is ON.

This four-wheel drive vehicle has the above-mentioned transfer device 1.
A controller 60 is provided to control the operation of the switching device 40 and the freewheel device 50 at 0, and the controller 60 includes a center differential 3 operated by the driver.
A signal a from a switch (center differential changeover switch) 61 that changes between 0 lock and free, and a switch (2-4 changeover switch) 62 that changes between 2-wheel drive and 4-wheel drive.
A signal C from a position switch, a limit switch, etc. that detects the state of the switching device 4o, and a signal d from the freewheel sensor 63 that detects the disconnected state of the freewheel device 5°. At the same time, a control signal e is inputted from the controller 60 to the actuator of the switching device 4o and the connecting and disconnecting solenoids 54 and 55 of the two-wheel device 5o.

f and g are output.

Next, the structure of the transfer device 10 will be explained with reference to FIG. 2.3.

As described above, this transfer device 1o has a sub-transmission 8!20 in which the engine output is decelerated by the transmission according to the gear position and then inputted, and the output of the sub-transmission 20 is transferred to the front and rear wheels. It has a center differential 30 that is divided into two sides.

Of these, the auxiliary transmission 20 is constituted by a planetary gear mechanism in which a transmission output shaft 21 is selectively connected to a sun gear 23 or a binion carrier 24 through a switching sleeve 22, as shown in outline in FIG. There is. Since the ring gear 25 of this planetary gear mechanism is fixed and the binion carrier 24 is connected to the intermediate shaft 26 that transmits power to the center differential 30, the transmission output shaft 21 is fixed to the binion carrier 24, as shown by the solid line. When connected to the on-carrier 24, the rotation of the shaft 21 is directly transmitted to the intermediate shaft 26, and when the transmission output shaft 21 is connected to the sun gear 23, the rotation of the shaft 21 is transmitted as is, as shown by the chain line. The deceleration is then transmitted to the intermediate shaft 26.

Further, the center differential 30 is also constituted by a planetary gear mechanism, and the intermediate shaft 26 is connected to a binion carrier 31 of the planetary gear mechanism, and the ring gear 3
2 is connected to the second output shaft 12 that outputs power to the rear wheels. In addition, the sun gear 3 of the planetary gear mechanism
Reference numeral 3 denotes a clutch mechanism 41 constituting the switching device 40 and a drive side sprocket 71 constituting a chain type transmission mechanism provided between the intermediate shaft 26 and the first output shaft 11.
, the first output shaft 11 via a chain 72 and a driven sprocket 73.

On the other hand, the switching device 40 is composed of the clutch mechanism 41 described above, an operating device 11142 for operating the same, a motor 43 as an actuator, and an operating force setting V&horizontal 44 for setting the operating force by the motor 43. There is.

Of these, the clutch device 'n441 includes a clutch hub 81 connected to an extension of the sun gear 33 in the center differential 30, a first clutch gear 82 integrally provided with the ring gear 32, and a drive for the chain type transmission mechanism. It is composed of a second clutch gear 83 that is integrally provided with the side sprocket 71, and a switching sleeve 84 that is slidably spline-fitted over the second clutch gear 83. In this embodiment, a synchronizer ring 85 is interposed between the clutch hub 81 and the second clutch gear 83 to synchronize their rotations.

Here, the switching sleeve 8 in this clutch mechanism 41
To explain the relationship between position 4 and power transmission state, first,
When the sleeve 84 is located at the left stroke end in the drawing, the clutch hub 81 and the second clutch gear 83 are coupled, and the sun gear 33 of the center differential 30 is coupled to the drive side sprocket 71 of the transmission mechanism. . As a result, the center differential 30 has one output element, the sun gear 33, connected from the first output shaft 11 to the front wheels, and the other output element, the ring gear 32, connected from the second output shaft 12 to the rear wheels. A four-wheel drive state is established in which the power input from the on-carrier 31 is transmitted to the front and rear wheels, respectively, and in this case, differential operation between the sun gear 33 and the ring gear 32 is allowed, and the power is transmitted between the front and rear wheels. This is a center differential-free four-wheel drive type B (hereinafter referred to as 4WF) that can generate a rotational speed difference of .

In addition, at an intermediate stroke position where the sleeve 84 is slid a certain amount to the right in the drawing from this state, the sleeve 84 engages the clutch hub 81 and the first and second clutch gears 82 and 83 on both sides thereof. As a result, the power input to the binion carrier 31 of the center differential 30 is output from the sun gear 33 to the front wheel side and from the ring gear 32 to the rear wheel side. The vehicle enters a four-wheel drive state in which the wheels are driven, but in this case, the sun gear 33 and ring gear 32 are coupled to prevent these differential operations and drive the front and rear wheels equally. The vehicle enters a four-wheel drive state (hereinafter referred to as 4WL) with a center differential lock.

Further, from this state, when the sleeve 84 slides to the right in the drawing and is located at the right stroke end as shown by the solid line in FIG. The coupling between the clutch hub 81 and the second clutch gear 83 is released. Therefore, center differential 30
remains locked, and the transmission of power from the center differential 30 to the first output shaft 11 or the front wheels is cut off, resulting in a two-wheel drive type R (hereinafter referred to as "R") in which power is transmitted only to the rear wheels. , 2W).

Also, an operating mechanism 42 that operates this clutch mechanism 41
includes a cylindrical cam 91 rotated by the motor 43 via the operating force setting mechanism 44, a shift rod 93 having a follower 92 engaged with a cam groove 91a in the cam 91, and a shift rod 93 fixed to the shift rod 93. and a shift fork 94 that is engaged with the switching sleeve 84 of the clutch mechanism 41. The rotation of the cylindrical cam 91 by the motor 43 causes the switching sleeve 8 to move through the shift rod 93 and shift fork 94.
4 is slid to the left and right stroke ends and an intermediate position as described above.

Next, the operating force setting mechanism 44 in the switching device 40 will be explained with reference to FIGS. 4 and 5.

This operating force setting mechanism 44 includes a drive gear 102 made of an insulator that meshes with a gear 101 on the rotating shaft of the motor 43.
and a driven gear 106, which is also made of an insulator and is disposed coaxially with the gear 102 and facing each other, and is connected to a gear 105 on the rotating shaft 91b of the cylindrical cam 91 via reduction gears 103 and 104. The leg portions 1 are wound around a common shaft 107 of the driving gear 102 and the driven gear 106, and the leg portions 1 at both ends
08a and 108a are driven gears 1 in the drive gear 102
A pair of bottles 102a, 10 protruding from the surface facing 06
2a, and coil springs 108 respectively engaged with the coil springs 2a. A pair of bins 106a and 106 are also provided on the surface of the driven gear 106 facing the drive gear 102.
a is provided protrudingly, and the leg portion 1 of the coil spring 108 is
08a and 108a, respectively, and when the drive gear 102 rotates, the coil spring 10
When one of the legs 108a of the coil spring 10.8 pushes one of the bins 106a on the driven gear 106 side, rotation is transmitted to the driven gear 106 via the elastic force of the coil spring 10.8. . At that time, the driven gear 10
By bending the coil spring 108 in accordance with the load on the 6 side, the driving gear 102 and the driven gear 106 rotate relative to each other by an amount corresponding to the load.

Further, first and second brushes 109a and 109b are attached to the surface of the drive gear 102 facing the driven gear 106 at different positions in the radial direction, and a sixth
As shown in the figure, the drive gear 10 in the driven gear 106
A conductive plate 110, which together with the brushes 109a and 109b constitute a limit switch, is attached to the surface facing the brushes 2. This conductive plate 110 includes both the gears 102.10 and 102.10.
When there is no relative rotation between the brushes 109a and 10
A narrow first notch 1 centered on the neutral position where the brush 9b is located and corresponding to the first brush 109a on the outside in the radial direction.
10a, and a wide second notch 1 centered on the neutral position and corresponding to the radially inner second brush 109b.
10b, and the conductive plate 110 is held at a predetermined potential (plus or minus potential of the power source). As a result, the operating force of the motor 43, which is composed of the first brush 109a and the first notch 110a and corresponds to the relative rotation between the driving gear 102 and the driven gear 106, is relatively small at the first predetermined value P! (For example, 40
a first limit switch 111 that becomes conductive when Kg> or more;
A second limit switch 112 that is composed of a second brush 109b and a second notch 110b and is electrically connected when the operating force is greater than a second predetermined value P2 (for example, 80 kg).
is made up of.

Further, as shown in FIG. 4, a disk 113 made of an insulator is fixed to the rotating shaft 91b of the cylindrical cam 91, and three arcuate conductive plates 114a, 114b,
114c are attached concentrically, and three brushes 115a, 11 are attached in correspondence with these guides, respectively.
5b and 115C are provided, and these cylindrical cams 9
The first to third position switches 116, 117, and 118 for detecting the rotation angle of 1, that is, the position of the switching sleeve 84 in the clutch mechanism 41 are oval shaped. ,
As shown in FIG. 7, the combination of OFF and OFF positions the sleeve 84 at the 2W position at the right stroke end, the 4WL position at the center of the stroke, and the 4WF position at the left stroke end.
position, and the first and second positions between each of these positions.
A total of five positions, including intermediate positions α and β, can be detected.

The center differential changeover switch 61 shown in FIG.
-4 changeover switch 62 is constituted by a changeover button provided on the changeover lever. And the switching lever 6
1 is in the intermediate position shown by the solid line, the center differential 30 is locked (4WL) in the four-wheel drive state, and the switching lever 61 is in the upper position shown by the chain line when the switching button 6 is pressed.
2 is operated, switching between a center differential free four-wheel drive state (4WF) and a two-wheel drive state (2W) is performed. Furthermore, by operating the switching lever 61 to the lower position shown by the chain line, the sub-transmission 20 is operated to the lower gear side in the 4WL state.

Next, the switching control operation by the controller 60 shown in FIG. 1 will be explained with reference to the flowcharts in FIG. 9 and subsequent figures.

First, the main routine of this switching control operation will be explained with reference to the flowchart in FIG. Signals from the switch switches 116 to 118 are input, and the combinations of ON and OFF indicated by these signals are compared with the combinations of ON and OFF for each preset position shown in FIG. Then, when the actual combination does not correspond to any of the set combinations, it is determined that a failure has occurred in one of the position switches 116 to 118, and the position switch failure mode control is executed in step S4. do.

Further, when switching from the two-wheel drive state to the four-wheel drive state is detected based on the signal from the 2-4 changeover switch 62, the clutch hub 81 and the second clutch gear 83 in the clutch mechanism 41 are connected in step S5. When it is determined that the synchronization operation has not been performed normally, steps S6 to S7 are executed to control the synchronization failure mode.

If the position switch failure and synchronization failure as described above have not occurred, normal switching control in step S8 is executed.

This normal switching control is performed according to the flowchart in FIG. 10. First, in step S11, the switching sleeve 84 is
The current position of the center differential changeover switch 61 and the 2-4 changeover switch 62 is determined in step S12.
The target position for realizing the drive mode selected by the driver is determined based on the signal from the driver.

Then, step SI3. In S14, the rotation direction and operating force of the motor 43 in the switching device 40 are set, and
In step SL5, the drive of the motor 43 is controlled so as to obtain the direction and operating force obtained by these setting operations, and further, in step S+6, the freewheel device 50 is controlled.

The determination of the target position in step S1□ above is performed in the first
The process is performed as follows according to the flowchart in FIG.

First, in step S21, it is determined whether or not the engine ignition switch has just been turned on, and if it has been turned on, it is determined in step S2□ whether or not the center differential changeover switch 61 is on the lock side, that is, as shown in FIG. It is determined whether the switching lever 61 shown is at the intermediate position 4WL.

When the lever 61 is operated to the 4WL position, the target position of the switching sleeve 84 in the clutch mechanism 41 is also set to the 4WL position in step S23, and the position flag FP is set to O in step S24.

Further, if the switching lever 61 is not operated to the 4WL position, steps S22 to S25 are executed to determine whether the current position of the sleeve 84 is at the 2W position based on the signals from the position switches 116 to 118. If it is in the 2W position, step S
26. In S27, the target position of the sleeve 84 is set to the 2W position, and the position flag FP is set to 1.

Furthermore, the switching lever 61 is not in the 4WL position (2
W, 4WF selection position), and the sleeve 84
If the current position of is not at the 2W position (it is at the 4WL, 4WF position or intermediate positions α and β), step S2
At step 8, it is determined whether or not the freewheel device 50 is connected based on a signal from the sensor 63 that detects the disconnected state of the freewheel device 50. If it is connected, the target position of the sleeve 84 is set to the 4WF position in step S29, and the position flag Fp is set to 0 in step S24, and if the freewheel device 50 is disconnected. is the above step S26. Execute S27 and set the target position to 2.
At the same time, the position flag FP is set to 1.

On the other hand, after the ignition switch is turned ON, that is, after the engine starts, steps S21 to S330 are executed, and it is again determined whether the center differential changeover switch (switching lever) 61 is in the 4WL position. , if it is at the 4WL position, the target position of the switching sleeve 84 is also set to the 4WL position in step S3□, and the position flag FP is set to O in step S24.
Set to . If the switching lever 61 is in the 2W or 4WF selection position, it is determined in step S32 whether the 2-4 switching switch, that is, the switching button 62 shown in FIG. Step S3
The value of the position flag FP already set in S is determined, and if Fp=1, the target position of the switching sleeve 84 is set to the 2W position in step S34, and Fp
If =O, the target position of the sleeve 84 is set to the 4WF position in step SSS. Furthermore, if the 2-4 changeover switch (changeover button) 62 is operated, the value of the position flag FP is determined in step S36, and F2=
If it is 1, F p = 0 in step S37 and the target position is set to 4WF position in step S35, and if F p = O, F p = 1 in step 338 and the target position is set to 2W in step S34. Set to position.

As described above, the target position of the switching sleeve 84 is set during and after engine startup according to the position of the switching lever (center differential switching switch) 61 and the operation of the switching button (2-4 switching switch) 62. However, especially when the engine is started, the switching lever 61 is in the 2W or 4WF selection position, and the switching sleeve 84 is
are at intermediate positions α and β, if the freewheel device 50 is connected, the target position of the sleeve 84 is the 4WF position, and if the freewheel device 50 is disconnected, the target position of the sleeve 84 is the 4WF position. Position is 2W
They will be set at each location. As a result, in any case, the following control enables the vehicle to start reliably and quickly in a four-wheel drive state or a two-wheel drive state.

Once the target position of the switching sleeve 84 is set in this way, the motor rotation direction is set in step StS of the flowchart of FIG. 10, but this operation is performed as follows according to the flowchart of FIG. It is done like this.

First, in step S41, turn on the ignition switch.
It is determined whether it is immediately after, and if it is immediately after, then step S
42+343, the first and second limit switches 111,
112 is in the ON state. If both limit switches are OFF, step S
The execution flag Fo is set to 1 in step S44, and if at least one limit switch is ON, the execution flag Fo is set to 1 in step S45. Set to 0.

Next, in step S46, the value of the execution flag FO is determined, and if F o = 1, the motor rotation direction setting operation in step 347 and subsequent steps is performed.

That is, in step S47+848, it is determined again whether the first and second limit switches 111, 112 are in the ON state, and if both limit switches are OFF, the rotation permission flag in the X direction is set in step S49. , and the rotation permission flag FAY in the Y direction are both reset to 0. Here, the X direction is the direction in which the sleeve 84 in the clutch mechanism 41 shown in FIG. This is the direction in which it slides in the opposite direction.

On the other hand, when at least one of the first and second limit switches 111 and 112 is in the ON state, step S
Steps S and O are executed from step 47 or step 34g, and the value of the Y-direction rotation flag Fy indicating that the motor 43 is rotating in the Y-direction is determined. And F y =
1, that is, when the motor 43 is currently rotating in the Y direction, it is confirmed in step S51 that the rotation permission flag FAY in the Y direction is O, and then step S51 is performed.
At step 52, the rotation permission flag FAX in the X direction is set to 1. Further, when the Y-direction rotation flag F y = O, the value of the X-direction rotation flag FX indicating that the motor 43 is rotating in the X direction is determined in step S53, and when Fx = 1, that is, the value of the is actually rotating in the X direction, it is confirmed in step S54 that the rotation permission flag FAX in the X direction is 0, and then in step S55
Set the rotation permission slug FAY in the Y direction to 1. In this manner, while the motor 43 is rotating in the X direction or the Y direction, the first and second limit switches 111,
112 is in the ON state, on the condition that the rotation permission flag FAX or FAY for the currently rotating direction is reset to O.
Rotation permission flag FAY or F for rotation in the opposite direction
Set AX to 1. This allows the motor 43 to rotate in the direction in which the limit switches 111 and 112 are turned off, and prevents rotation in both directions from being permitted at the same time.

Further, the operation force setting operation in step S14 of the flowchart in FIG. 10 is performed according to the flowchart in FIG.
Next, in step S62, the second limit switch 11
2 is ON, and if it is ON, both of the operating force restriction flags FIX and FIY are held at 1. This second limit switch 112 is turned on when the operating force of the motor 43 is equal to or greater than the second set value P2 (80 kg), so when such a large operating force occurs, the second limit switch 112 is turned on. The signal causes the motor to be de-energized, thereby preventing overload from acting on the motor 43. Also, the second limit switch 1
12 is OFF, it is determined in step S63 whether or not the first limit switch 111 is ON. If the first limit switch 111 is also OFF, that is, the operating force of the motor 43 is equal to the first set value P+(40Kg ), the X-direction and Y-direction operating force restriction flags FIX and FIY are both reset to 0 in step S64. As a result, both limit switches 111 and 112 are turned OFF.
In the case of F, the signals from these switches 111 and 112 are ignored, and the motor 43 is allowed to be energized in the X and Y directions.

Furthermore, the second limit switch 112 is OFF and the first limit switch 112 is OFF.
When the limit switch 111 is ON, that is, when the operating force of the motor 43 is within the range from the first set value P1 to the second set value P2 (40 kg to 80 kg), the current position is moved in the Y direction from the 4WL position in step S65. side,
That is, it is determined whether the position is either the 2W position or the first intermediate position α, and if these positions are present, the X-direction operating force limitation flag FIX is reset to O in step S66. If the current position is not on the Y-direction side of the 4WL position, it is determined in step S67 whether the current position is the 4WF position, and if the current position is in the 4WF position, the operation force in the X direction is determined in step 868. Reset the limit flag FIY to 0.

As a result, as shown by the X mark in FIG. 14, the ON signal from the first limit switch 111 is ignored at the 2W 4fl position and the first intermediate position α in the X direction,
For the direction, set the first limit switch 11 at the 4WF position.
The ON signal from 1 is ignored, and in these positions, the operating force of the motor 43 is allowed up to the second set value Pz (80 kg) at which the second limit switch 112 is turned ON. In other positions (marked with a circle in FIG. 14), the operating force is limited to the first set value P+ (40 kg) at which the first limit switch 111 is turned on.

When the rotational direction and operating force of the motor 43 are set as described above, the motor is controlled in step SI4+ of the flowchart of FIG. 10, but this control is performed as follows according to the flowchart of FIG. It is done like this.

In this control, it is first determined in step S71 whether the current position matches the target position, and if they match, the X-direction and X-direction rotation flags Fx and Fy are reset to 0 in step S72. do. In other words,
In this case, the motor 43 is not rotated.

On the other hand, if the current position does not match the target position, it is determined in step S73 whether the current position is on the X direction side of the target position, and if it is on the X direction side, that is, if you want to operate in the X direction. In step S7
After resetting the rotation flag FX in the X direction to O in step 4,
At step s7+t, the rotation permission flag FAY in the X direction is set to 1.
However, it is judged whether or not. If FAy=1, the rotation flag FY in the X direction is set to 1 in step S76. If FAY=O, the value of the X-direction operating force limit flag FIY is determined in step S77, and FIY
- If yes, set the rotation flag FY in the X direction to 1 in step S76, and if FIY=1, set the X direction rotation flag FY to 1 in step S76.
Set the direction rotation flag FY to O.

In other words, when operating in the X direction, the motor 43 in that direction
If rotation is permitted, the motor 43 is driven in that direction; if not, the motor 43 is driven or stopped depending on the states of the first and second limit switches 111 and 112.

Further, if the current position is not on the X direction side of the target position, that is, if you want to operate in the X direction, step S7
At step 9, it is determined whether the freewheel device 50 is in the disconnected state, and if it is in the disconnected state, it is further determined at step sgo whether the current position is on the X direction side of the 4WL position. Then, if the position is on the X direction side of the 4WL position, that is, the 2W position or the first intermediate position α, step 374
-878 are executed to stop the operation in the X direction from the current position, and drive the motor 43 in the opposite X direction depending on the states of the flags FAY and FIY. This is to prevent switching from two-wheel drive to four-wheel drive while the freewheel device 50 is disconnected.

Then, when you want to operate in the X direction, if the freewheel device 50 is connected, and even if the device 50 is disconnected, the current position is at the 4WL position or on the X direction side from the position. In step Sat, the X-direction rotation flag FY is reset to O, and at the same time, in step S82, the value of the X-direction rotation permission flag FAX is determined, and if FAχ=1, the X-direction rotation flag FX is set in step S8S. Set to 1. In addition, if FAX=O, in step S84, the operating force limit flag F' in the X direction is set.
Determine the value of +x, and if F+x=O, step S83
In step S85, the rotation flag FX in the X direction is set to 1, and if F+x=1, the rotation flag FX is set to O in step S85.

As a result, similarly to the operation in the X direction described above, if rotation of the motor 43 in the X direction is permitted, the motor 43 is driven in that direction, and if not permitted, the motor 43 is driven in the first direction. The motor 43 will be driven or stopped depending on the state of the second limit switch 111, 112.

As described above, the motor 43 is driven and the switching sleeve 84 in the clutch device 141 is slid from the current position to the target position. Operated in the X direction and Y from the 4WF position to the second intermediate position β
As mentioned above, the ON signal of the first limit switch 111 is ignored and the first set value P+
(40 kg), switching operations are performed reliably and quickly, and between other positions, the first limit switch 11
The energization of the motor 43 is stopped by the ON signal of 1,
By limiting the operating force to less than the first set value P1, occurrence of switching shock, etc. is suppressed.

Furthermore, control of the freewheel device 50 in step SI6 of the flowchart of FIG. 10 is performed as follows according to the flowchart of FIG. 16.

First, in step S91, it is determined whether the current position of the switching sleeve 84 is the 2nd position. If it is in the second position, then in step S92, the freewheel connection solenoid 54 shown in FIG. 1 is turned off and the disconnection solenoid 55 is turned on. As a result, during two-wheel drive, the freewheel device 50 is disconnected, and the rotation of the front wheel, which is a driven wheel, is transferred from the first output shaft 11 of the transfer device 10 to the clutch mechanism 41 via the chain type transmission mechanism.
This prevents the back drive from being input to the second clutch gear 83, thereby avoiding drive loss due to such back drive.

Further, if the switching sleeve 84 is not at the 2nd position, it is determined in step S93 whether the current position of the sleeve 84 is at the 4WL position, the second intermediate position β, or the 4WF position, and whether or not the switching sleeve 84 is at the 2nd position is determined. If so, step S9
4, the connection solenoid 54 is turned ON and the disconnection solenoid 55 is turned OFF. As a result, the freewheel device 50 is connected and the required four-wheel drive state is obtained. In addition, the switching sleeve 84 is in the 2 position and 4W position.
If the position is at the first intermediate position α between the L positions, step S
95, both connecting and disconnecting solenoids 54.5
5 to OFF, in preparation for when the freewheel device 50 is then connected or disconnected.

(Effects of the Invention) As described above, according to the present invention, the 2-4 switching mechanism for switching between the two-wheel drive state and the four-wheel drive state is operated by an actuator, and In a 4-wheel drive vehicle equipped with a freewheel mechanism that shuts off the drive system of the wheels that serve as driving wheels, when the 2-4 switching mechanism is in operation, it is possible to switch between the 2-wheel drive position and the 4-wheel drive position!
If the freewheel mechanism is connected when the engine is started next time, the actuator will operate to the 4-wheel drive position and the vehicle will be able to start in 4-wheel drive, and the freewheel mechanism will be disconnected. If so, the actuator operates to the two-wheel drive position, and the vehicle becomes ready to start in the two-wheel drive state. As a result, the actuator is in the middle position as shown above! Basically, even if the vehicle is stopped, it can be started immediately in four-wheel drive mode, and even if the freewheel mechanism is disconnected, it can be started reliably and quickly in two-wheel drive mode. becomes possible.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention; FIG. 1 is a diagram of a switching control system for a four-wheel drive vehicle according to the embodiment, and FIG.
Main part sectional view of transfer device in wheel drive vehicle, 3rd
The figure is also a schematic diagram, and Figure 4 is a perspective view of the operating force setting mechanism.
Fig. 5 is a perspective view of the main parts of the mechanism, Fig. 6 is a front view of the driven gear in the mechanism, Fig. 7 is an explanatory diagram of the operation of the position switch, and Fig. 8 is a view of the driver's seat of the vehicle showing the switching lever. 9 is a flowchart showing the main routine of the control operation, FIG. 10 is a flowchart showing the control operation in normal conditions, FIG. 11 is a flowchart showing the operation for determining the target position of the switching device, and FIG. Figure 13 is a flowchart showing the motor rotation direction setting operation, Figure 13 is a flowchart showing the operation force setting operation, Figure 14 is an explanatory diagram of the operation force set by the operation, and Figure 15 is the motor control operation. FIG. 16 is a flowchart showing the control operation of the freewheel device. 41...2-4 switching mechanism (clutch mechanism), 43...
・Actuator (motor), 50... Freewheel mechanism, 60... Control means (controller), 63.
・・Freewheel detection means (freewheel sensor)
, 116-118...operation position detection means (position sensor). Figure Figure Figure 5 Figure 8 Figure Figure Figure Figure 8 Figure Figure Figure Figure 8

Claims (1)

[Claims] (1) Drive only either the front wheels or the rear wheels 2
A 2-4 switching mechanism that switches between a wheel drive state and a four-wheel drive state that drives front wheels and rear wheels, an actuator that operates the 2-4 switching mechanism, and a drive wheel that becomes a driven wheel when driving two wheels. A 2-4 switching control device for a four-wheel drive vehicle, which is provided with a freewheel mechanism for disconnecting the system, comprising: an operating position detection means for detecting an operating position of the 2-4 switching mechanism by the actuator; A freewheel detection means detects the connection/disconnection state of the mechanism, and when the engine starts, the operation position of the 2-4 switching mechanism by the actuator receives the output from both of the above detection means, and the operation position of the 2-4 switching mechanism is an intermediate position between the 2-wheel drive position and the 4-wheel drive position. , if the freewheel mechanism is disconnected, the 2-4 switching mechanism is operated to the 2-wheel drive position, and if the freewheel mechanism is connected, the 2-4 switching mechanism is operated to the 4-wheel drive position. 1. A 2-4 switching control device for a four-wheel drive vehicle, characterized in that a control means is provided.