JP2692000B2 - 2-4 switching control device for four-wheel drive vehicle - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a four-wheel system in which a four-wheel drive state and a two-wheel drive state are switched by an actuator, and the operating force of the switching operation by the actuator is variable. The present invention relates to a 2-4 switching control device for a driving vehicle.

(Prior Art) In a four-wheel drive vehicle in which the front wheels and the rear wheels are driven by the engine output, the front wheels and the rear wheels are selected by the driver as described in, for example, Japanese Utility Model Publication No. 63-28646. It is possible to switch between a four-wheel drive state in which the wheels are driven and a two-wheel drive state in which only one of the front wheels and the rear wheels is driven, and the operation is performed by an actuator in order to improve the switching operability. There are things to do.

In this case, a switching mechanism that connects or disconnects the power transmission path to either one of the front wheels or the rear wheels is provided on the power transmission path, and the switching mechanism includes a drive side member and a driven side member. A meshing clutch type that connects or disconnects the above-mentioned members by sliding a sleeve fitted with a spline is generally used, and this sleeve is configured to be slid by an actuator.

Further, when the switching mechanism is operated by the actuator in this manner, it is possible to prevent the actuator from being overloaded due to some abnormality, to surely and quickly perform the switching operation, and to suppress the switching shock as much as possible. For example, in the case where the above-mentioned meshing clutch type switching mechanism is used, an operating force varying means for setting the operating force by the actuator to a different value for each switching operation is provided. When switching from the four-wheel drive state to the four-wheel drive state, it is necessary to synchronize the driving side member and the driven side member, so that the operating force by the actuator is set to a large value and the four-wheel drive state is changed to the two-wheel drive state. At the time of switching, in order to prevent a switching shock due to a sudden interruption of the transmission of driving force to one wheel, It has been considered that such setting the operation force by Chueta to a small value.

(Problems to be Solved by the Invention) By the way, as described above, while operating the switching mechanism between the two-wheel drive state and the four-wheel drive state by the actuator,
When the operating force varying means for changing the operating force is provided and the operating force is set to a small value in order to suppress the switching shock when switching from the four-wheel drive state to the two-wheel drive state, In such a case, the switching operation time is unnecessarily lengthened.

That is, at the time of switching from the two-wheel drive state to the four-wheel drive state, the drive side member and the driven side member in the switching mechanism are not properly synchronized, and therefore, before the switching to the four-wheel drive state is completed. When the sleeve is once returned to the two-wheel drive side, it has not been switched to the four-wheel drive state, so the actuator operates with a small operating force even though the above-mentioned shock at the time of switching from 4 to 2 does not occur. Therefore, the returning operation to the two-wheel drive side is performed unnecessarily slowly, and it takes a long time.

Further, such a defect is not limited to the occurrence of synchronization failure in the switching mechanism, and the switching to the four-wheel driving state is completed after the driver performs the switching operation from the two-wheel driving state to the four-wheel driving state. The same occurs when the switching operation to the two-wheel drive state is performed again before, and it takes a long time to return the actuator to the two-wheel drive side.

The present invention has the above-mentioned disadvantages in a four-wheel drive vehicle provided with an actuator for operating a switching mechanism between a two-wheel drive state and a four-wheel drive state, and an operation force varying means for changing an operation force by the actuator. To deal with
When switching from two-wheel drive mode to four-wheel drive mode, when the switching mechanism is out of synchronization, or when the driver operates 2 → 4 → 2, the switching operation should be performed as quickly as possible while avoiding the occurrence of switching shock. The task is to let them do it.

(Means for Solving the Problems) In order to solve the above problems, a 2-4 switching control device for a four-wheel drive vehicle according to the present invention is characterized by being configured as follows.

First, an invention according to claim 1 of the present application (hereinafter, referred to as a first invention) is a two-wheel system that drives only the other wheel by connecting and disconnecting a power transmission path to one of the front wheel and the rear wheel. Four-wheel drive having switching means for switching between a driving state and a four-wheel driving state for driving the front wheels and the rear wheels, an actuator for operating the switching means, and an operation force varying means for changing an operation force by the actuator In the vehicle, when the four-wheel drive state is switched to the two-wheel drive state, the operating force of the actuator is set to a small value while
At the time of switching from the four-wheel drive state to the four-wheel drive state, the actuator is moved from the four-wheel drive side to the two-wheel drive side before completion of switching to the four-wheel drive state due to poor synchronization between the driving side member and the driven side member of the switching means. It is characterized in that an operating force setting means for setting the operating force of the actuator to a large value is provided when returning to the driving side once.

The invention according to claim 2 of the present application (hereinafter referred to as the second invention) is a switching means similar to the first invention, an actuator for operating the switching means, and an operating force for changing the operating force by the actuator. In a four-wheel drive vehicle having a variable means, when the four-wheel drive state is switched to the two-wheel drive state, the operating force of the actuator is set to a small value, while the driver changes the two-wheel drive state to the four-wheel drive state. After switching to the 4 wheel drive mode, complete 2
An operating force setting means for setting the operating force of the actuator to a large value is provided when the actuator returns from the four-wheel drive side to the two-wheel drive side when the switching operation to the wheel drive state is performed. And

(Operation) According to the above configuration, the operating force by the actuator is set to a small value at the time of switching from the four-wheel drive state to the two-wheel drive state in both the first and second inventions. The switching shock when the transmission of the driving force to one of the wheels is interrupted is suppressed. According to the first aspect of the invention, the actuator is temporarily returned to the two-wheel drive side before the completion of the switching to the four-wheel drive state because of the poor synchronization of the switching mechanism at the time of switching from the two-wheel drive state to the four-wheel drive state. At the same time, according to the second aspect of the present invention, the switching operation to the two-wheel drive state again immediately after the driver performs the switching operation from the two-wheel drive state to the four-wheel drive state completes the switching to the four-wheel drive state. When the actuator returns to the two-wheel drive side before, the returning operation to the two-wheel drive side is performed with a large operation force. In other words, if there is no problem of shock when switching from 4 to 2, 2 from the 4 wheel drive side
Since the operation on the wheel drive side is performed with a large operation force, it is possible to avoid prolonging the time required for this operation.

(Examples) Hereinafter, examples of the present invention will be described.

First, the structure common to the embodiments of the first and second inventions will be described with reference to FIGS. 1 to 8. FIG. 1 shows a schematic structure of a four-wheel drive vehicle according to the embodiment and its control system. The four-wheel drive vehicle according to this embodiment includes a transfer device 10 to which an engine output is input via a transmission (not shown), and a first output shaft 11 that projects forward to the device 10. ,
A second output shaft 12 protruding rearward is provided. The first output shaft 11 reaches the front wheels via the propeller shaft 13, the front wheel differential device 14, and the left and right front axles 15 and 16. Also, although not shown, the second output shaft 12 is also a propeller shaft,
The rear wheels are reached via the rear wheel differential device and the left and right rear wheel shafts.

As described later, the transfer device 10 has an auxiliary transmission 20, a center differential 30, and a switching device 40 as main components (see FIGS. 2 and 3). The transfer device 10 includes a two-wheel drive state in which the power from the auxiliary transmission 20 is transmitted only from the second output shaft 12 to the rear wheel side, and a two-wheel drive state in which the first and second output shafts 11 and 12 It is possible to switch between a four-wheel drive state that outputs to the rear wheel side.
In the wheel drive state, the center differential 30 is differentially operated to allow a difference in rotational speed between the front and rear wheels to be allowed, and the center differential 30 is prevented from being differentially operated. It is possible to switch to the state of the center diff lock that drives evenly.
It is supposed to be done by.

Further, the front wheel differential device 14 is provided with a freewheel device 50 for connecting / disconnecting power transmission to one front axle 16, and a negative pressure type actuator 51 for driving the device 50. This actuator 51 has a first and a second
The negative pressure passages 52 and 53 are connected, and the free wheel connecting solenoid 54 and the disconnecting solenoid 55 are arranged in the negative pressure passages 52 and 53, respectively, and the connecting solenoid 54 is turned on and the disconnecting solenoid 55 is connected. When it is OFF, the freewheel device 50 is connected and the connecting solenoid 54 is OF
F, the freewheel device 50 is disconnected when the disconnecting solenoid 55 is ON.

The four-wheel drive vehicle includes the transfer device
A controller 60 for controlling the operation of the switching device 40 and the freewheel device 50 in 10 is provided.
The signal a from the switch (center differential switch) 61 for switching the center differential 30 between locked and free,
A signal b from a switch (2-4 changeover switch) 62 for switching between two-wheel drive and four-wheel drive, a signal c from a position switch or a limit switch for detecting the state of the changeover device 40, and the freewheel. A signal d from a sensor 63 that detects the state of the device 50 is input, and a solenoid for connection and disconnection that drives the actuator of the switching device 40 and the actuator 51 of the freewheel device 50 from the controller 60. Control signals e, f, and g are output to 54 and 55, respectively.

Next, the structure of the transfer device 10 will be described with reference to FIGS.

As described above, the transfer device 10 includes the auxiliary transmission 20 to which the engine output is decelerated by the transmission according to the gear stage and the input, and the output of the auxiliary transmission 20 to the front wheel side and the rear wheel side. And a center differential 30 which is divided into

Of these, the auxiliary transmission 20 has a transmission output shaft 21 connected to a sun gear by a switching sleeve 22 as schematically shown in FIG.
23 or a planetary gear mechanism selectively connected to the pinion carrier 24. Since the ring gear 25 of this planetary gear mechanism is fixed and the pinion carrier 24 is connected to the intermediate shaft 26 that transmits power to the center differential 30, as shown by the solid line, the transmission output shaft 21 is connected to the pinion carrier. When connected to 24, the rotation of the shaft 21 is directly transmitted to the intermediate shaft 26,
When the transmission output shaft 21 is connected to the sun gear 23, the rotation of the shaft 21 is reduced and transmitted to the intermediate shaft 26.

The center differential 30 is also formed of a planetary gear mechanism, the intermediate shaft 26 is connected to the pinion carrier 31 of the planetary gear mechanism, and the ring gear 32 is connected to the second output shaft 12 that outputs power to the rear wheels. Have been. The sun gear 33 of the planetary gear mechanism is provided with a clutch mechanism 41 constituting the switching device 40 and the intermediate shaft 26.
The first output shaft 11 is connected to the first output shaft 11 via a driving sprocket 71, a chain 72, and a driven sprocket 73 that constitute a chain type transmission mechanism provided between the first output shaft 11 and the first output shaft 11. ing.

On the other hand, the switching device 40 includes the above-described clutch mechanism 41, an operation mechanism 42 for operating the clutch mechanism 41, a motor 43 as an actuator, and an operation force setting mechanism 44 for setting an operation force by the motor 43. .

Of these, the clutch mechanism 41 is connected to the center differential 30.
Clutch hub connected to the extension of sun gear 33 at
81, a first clutch gear 82 provided integrally with the ring gear 32, and a second clutch gear 83 provided integrally with the driving sprocket 71 of the chain type transmission mechanism. And a switching sleeve 84 fitted with splines.

Here, the switching sleeve 84 in the clutch mechanism 41
First, when the sleeve 84 is located at the stroke end on the left side in the drawing, the clutch hub 81 and the second clutch gear 83 are coupled to each other, so that the center differential described above is described. The sun gear 33 of 30 is coupled to the drive side sprocket 71 of the chain type transmission mechanism. As a result, in the center differential 30, the sun gear 33, which is one output element, is connected to the front wheel from the first output shaft 11, and the ring gear 32, which is the other output element, is connected to the rear wheel from the second output shaft 12, respectively. The four wheels are driven to transmit the power input from the carrier 31 to the front and rear wheels, respectively. In this case, the relative rotation between the sun gear 33 and the ring gear 33 is allowed, and the rotation between the front and rear wheels is allowed. This is a center differential free four-wheel drive state (hereinafter referred to as 4WF) in which a speed difference can be generated.

Further, from this state, at the stroke intermediate position where the sleeve 84 is slid to the right by a certain amount in the drawing, the sleeve 84 causes the clutch hub 81 and the first and second clutch gears 82 and 83 on both sides of the clutch hub 81 to move in the three positions. As a result of being connected, the power input to the pinion 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, respectively.
In this case, the front and rear wheels are driven in a four-wheel drive state. In this case, the sun gear 33 and the ring gear 32 are coupled to each other, so that their differential operation is prevented, and the front and rear wheels are evenly distributed. Center differential lock driven 4 wheel drive state (hereinafter 4W
L).

Further, from this state, when the sleeve 84 slides to the right side in the drawings and is located at the stroke end on the right side as shown in FIGS. 2 and 3, the sleeve 84 is attached only to the clutch hub 81 and the first clutch gear 82. The clutch hub 81 and the second clutch gear 83 are disengaged from each other by being engaged with each other. Therefore, the transmission of power from the center differential 30 to the first output shaft 11 or the front wheel side is cut off while the center differential 30 is locked, whereby the two-wheel drive in which power is transmitted only to the rear wheel side. State (hereinafter referred to as 2W).

When the switching sleeve 84 slides from the 2W position to the 4WL position shown in the drawing and meshes with the second clutch gear 83, it is necessary to synchronize the rotations of the clutch hub 81 and the second clutch gear 83. 81 and second clutch gear
The synchronizer ring 85 provided between the synchronizer ring 85 and the synchronizer ring 85 is connected to the second synchronizer ring 85 by the operating force of the sleeve 84.
The second clutch gear 83 is pressed against the clutch gear 83 side.
There is provided a synchronization mechanism including a key 86 for synchronizing the rotation of the sleeve 84 with the rotation of the sleeve 84.

In addition, the operating mechanism 42 for operating the clutch mechanism 41
Is 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 fixed to the shift rod 93. And the shift fork 94 engaged with the switching sleeve 84 in the clutch mechanism 41. The rotation of the cylindrical cam 91 by the motor 43 causes the switching sleeve 84 to slide between the left and right stroke ends and the intermediate position via the shift rod 93 and the shift fork 94 as described above.

Next, the operation force setting mechanism 44 in the switching device 40 will be described with reference to FIGS.

The operating force setting mechanism 44 includes a drive gear 102 made of an insulator meshed with a gear 101 on a rotation shaft of the motor 43, and a reduction gear 1 coaxially arranged with the drive gear 102 so as to face each other.
The gear 105 on the rotating shaft 91b of the cylindrical cam 91 through 03, 104.
And a driven gear 106, which is also made of an insulator, is wound around a common shaft 107 of the driving gear 102 and the driven gear 106, and legs 108a, 108a at both ends of the driven gear
A coil spring 108 is engaged with a pair of pins 102a, 102a protruding from a surface facing the coil 106. A pair of pins 106a and 106a are also provided on the surface of the driven gear 106 facing the driven gear 102 so as to abut against the leg portions 108a and 108a of the coil spring 108, respectively. When the coil spring 108 is rotated, one leg portion 108a of the coil spring 108 pushes one pin 106a of the driven gear 106 side, so that the coil spring 108
The rotation is transmitted to the driven gear 106 via the elastic force of 108. At this time, the coil spring 108 bends according to the load on the driven gear 106 side, so that the driving gear 102 and the driven gear 106 rotate relative to each other by an amount corresponding to the load.

The first and second brushes 109 are provided on the surface of the drive gear 102 facing the driven gear 106 at different positions in the radial direction.
While a and 109b are attached, as shown in FIG. 6, on the surface of the driven gear 106 facing the drive gear 102,
A conductive plate 110 that constitutes a limit switch together with the brushes 109a and 109b is attached. The guide plate 110 is provided with the brush 109 when there is no relative rotation between the gears 102 and 106.
A narrow first notch 110a corresponding to the first brush 109a on the outer side in the radial direction centered on the neutral position where a and 109b are located.
And a wide second notch 110b corresponding to the second brush 109b on the inner side in the radial direction centered on the neutral position, and the conducting plate 110 has a predetermined potential (positive potential of the power source). Or negative potential). As a result, the first set value, which is constituted by the first brush 109a and the first cutout 110a, and in which the operating force by the motor 43 corresponding to the relative rotation between the drive gear 102 and the driven gear 106 is relatively small.
The first limit switch that conducts at P ₁ (eg 40 kg) or more
111, the second brush 109b, and the second cutout portion 110b, and the second set value P ₂ (for example, 80 kg) having a large operation force is provided.
The second limit switch 112 that conducts the above is configured.

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 the disk
Three arc-shaped guide plates 114a, 114b, 114c are concentrically attached to the top of the three pieces, and three brushes 115a, 115b, 115c are provided in correspondence with these guide plates, respectively, and the cylindrical cam 91 The first to third position switches 116, 117 and 118 for detecting the rotation angle of the clutch mechanism 41, that is, the position of the switching sleeve 84 in the clutch mechanism 41 are configured. These position switches 116 to 118 are, depending on the combination of ON and OFF, as shown in FIG. 7, the 2W position at the stroke end on the right side of the sleeve 84, the 4WL position at the center of the stroke,
And 3 positions of the left stroke end 4WF position,
A total of 5 of the first and second intermediate positions α and β between these positions
The position can be detected.

The center differential changeover switch 61 shown in FIG. 1 is constituted by a changeover lever provided near the steering wheel in the driver's seat as shown in FIG. 8, and the 2-4 changeover switch 62 is provided on the lever. It is composed of a switching button. Then, when the switching lever 61 is at the intermediate position shown by the solid line, the center differential 30 is locked in the four-wheel drive state (4WL), and the switching button 62 is operated while the switching lever 61 is at the upper position shown by the chain line. Center differential free four-wheel drive state (4WF) and two-wheel drive state (2
W) is to be switched. Further, by operating the switching lever 61 to the lower position shown by the chain line, the auxiliary transmission 20 is operated to the low gear stage side in the 4WL state.

Next, the operation of the present embodiment will be described with reference to the flow charts of FIG. 9 and thereafter showing the switching control operation by the controller 60.

First, the operation of the embodiment according to the first invention will be described. FIG. 9 shows a main routine of this embodiment. The controller 60 first performs a predetermined system initialization in step S ₁ , In steps S ₂ and S ₃ , the signals from the first to third position switches 116 to 118 are input, and the ON / OFF combinations indicated by these signals and the preset positions shown in FIG. Compare with the combination of ON and OFF.
Then, when the actual combination does not correspond to any of the set combinations, it is determined that a failure has occurred in any of the position switches 116 to 118, and step S ₄
Control the position switch failure mode by.

Also, 2-4 when switching of on the basis of a signal from the changeover switch 62 from the two-wheel drive state to the four-wheel drive state is detected, the clutch hub 81 in the clutch mechanism 41 in step S ₅ the second clutch gear The synchronization state with 83 is determined, and when this synchronization operation is not normally performed, steps S ₆ to S ₇ are executed to control the synchronization failure mode.

When the failure and poor synchronization of position switch described above does not occur, performs normal switching control in step S _8.

This normal switching control is performed according to the flow chart of FIG. 10. First, in step S ₁₁ , the position switch 1
A target for realizing the drive mode selected by the driver by the signals from ₁₆ to 118 to determine the current position of the switching sleeve 84, and by the signals from the center differential switching switch 61 and the 2-4 switching switch 62 in step S12. Determine position.

Then, it sets the rotation direction and the operation force of the motor 43 in the switching device 40 in step S _13, S _14, step
In S _15, controls the driving of the motor 43 so that the resulting direction and the operating force by these setting operation.

Setting the rotational direction of the motor by the step S ₁₃ is first
The procedure is as follows according to the flowchart of FIG.

First, it is determined whether or not it is immediately after the ignition switch of the engine has been turned ON in step S _21, the first in the next step S _22, S ₂₃ if immediately after, the second limit switch 11
Determine whether 1,112 is in the ON state. Then, if any of the limit switches also OFF, the 1 execution flag F ₀ in step S _24, is one of the limit switches
If it is ON, the flag F ₀ is set to 0 in step S ₂₅ .

Next, determining the value of the execution flag F ₀ in step S _26, performs the steps S ₂₇ following the rotating direction of the motor of the setting operation if F ₀ = 1.

That is, in steps S ₂₇ and S ₂₈ , it is determined again whether or not the first and second limit switches 111 and 112 are in the ON state. If both limit switches are in the OFF state, in step S ₂₉ the rotation permission flag F in the X direction is set. Rotation allowance flag F in _AX and Y directions
_{All AYs} are reset to 0. Here, the X direction is a direction in which the sleeve 84 in the clutch mechanism 41 shown in FIG. 2 slides from the right side to the left side in the drawing, that is, the 2W → 4WL → 4WF direction, and the Y direction is the sleeve 84. It is the direction of sliding 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, the above step S ₂₇ or step S ₂₈ to step S ₃₀ is executed and Y of the motor 43 is changed.
The value of the Y-direction rotation flag F _Y indicating the rotation in the direction is determined.
When F _Y = 1 (that is, when the motor 43 is rotating in the Y direction), it is confirmed in step S ₃₁ that the Y direction rotation allowance flag F _AY is 0, and then step S
_{At 32} , the rotation allowance flag F _AX in the X direction is set to 1. When the Y direction rotation flag F _Y = 0, the value of the X direction rotation flag F _X indicating the rotation of the motor 43 in the X direction is determined in step S ₃₃ , and when F _X = 1, that is, the motor 43 when rotating in the X direction, set on at step S ₃₄ the rotation permitting flag a _AX of the X-direction was calculated as follows: 0, the rotation permission flag F _AY in the Y direction to 1 in step S ₃₅ To do.
In this way, while the motor 43 is rotating in the X direction or the Y direction, the first and second limit switches 111, 112
When at least one of the two turns ON, the rotation permission flag F _AY or F _AY for the rotation in the opposite direction is provided, provided that the rotation permission flag F _AX or F _AY for the current rotation direction is reset to 0. Set F _AX to 1. As a result, the rotation of the motor 43 in the direction in which the limit switches 111 and 112 are turned off is enabled, and rotation in both directions is prevented from being permitted at the same time.

The operation force of the setting operation by the step S ₁₄ of the flowchart of FIG. 10 is carried out in accordance with the flowchart of Figure 12, first, X direction and Y direction of the operation force limitation flag F _IX in step S _41, the F _IY 1 Set to. Then, in step S _42, the second limit switch 112 is equal to or ON, the case turned ON, the both operation force limitation flag F _IX, F
Hold _IY at 1. This second limit switch 112
When the operating force of the motor 43 is higher than the second set value P ₂ (80 kg)
Since it is turned on, when such a large operating force is generated, the motor 43 is activated by the signal from the second limit switch 112.
The power supply to the motor 43 is stopped, and the overload on the motor 43 is prevented. Also, if the second limit switch 112 is OFF, the first limit switch 111 is determined whether the ON in step S _43, also the first limit switch 111 when OFF, the ie operation of the motor 43 If the force is less than the first set value P ₁ (40Kg), step S
_{At 44} , the operation force limit flags F _IX and F _{IY in the} X and Y directions
Are both reset to 0. As a result, when both limit switches 111 and 112 are OFF, these switches 111 and
Regardless of the signal from 2, the energization of the motor 43 in the X and Y directions is allowed.

Further, when the second limit switch 112 is OFF and the first limit switch 111 is ON, that is, the operating force of the motor 43 is in the range from the first set value P ₁ to the second set value P ₂ (40 to 80).
When in Kg), in step S ₄₅ the current position is the Y-direction side of the 4WL position of the switching sleeve 84, that is, whether or not either of 2W position or the first intermediate position alpha, at these locations is reset to 0 the X direction of the operating force limitation flag F _IX in step S ₄₆ in cases. If the current position is not on the Y direction side of the above 4WL position,
Current position in step S ₄₇ it is determined whether the 4WF position and reset when in the 4WF position, the 0 in the Y direction of the operation force limitation flag F _IY in step S _48.

As a result, the ON signal from the first limit switch 111 is ignored at the 2W position and the first intermediate position α in the X direction, and 4
At the WF position, the ON signal from the first limit switch 111 is ignored, and at these positions, the operating force of the motor 43 causes the second limit switch 112 to turn ON. The second set value P ₂ (80K
g) will be acceptable. At any other position (marked with ○ in Fig. 13), the first limit switch
The operation force is limited by the first set value P ₁ (40Kg) where 111 turns ON.

When the rotation direction and the operation force of the motor 43 as described above is set, the control of the motor in step S ₁₅ of the flowchart of FIG. 10 is performed, the control is first
It is performed as follows according to the flowchart of FIG.

In this control, first, in step _S51 , it is determined whether or not the current position of the switching sleeve 84 matches the target position, and if they match, X is determined in step _S52 .
The rotation flags F _X and F _Y in the Y and Y directions are reset to 0. That is, in this case, the motor 43 is not rotated.

On the other hand, if the current position of the switching sleeve 84 does not coincide with the target position, the current position is equal to or in the X direction side of the target position in step S _53,
If it is on the X direction side, that is, if it is desired to operate in the Y direction, the rotation flag F _X in the X direction is reset to 0 in step S ₅₄ , and then the rotation permission flag F _AY in the Y direction in step S _55.
Is 1 or not. Then, in the case of F _AY = 1, it is set to 1 the rotation flag F _Y in the Y direction in step S _56. If F _AY = 0, the value of the Y direction operating force limit flag F _IY is determined in step S ₅₇ , and if F _IY = 0, the Y direction rotation flag F _{Y is set} to 1 in step S _56. And F _IY = 1
Sets the rotation flag F _Y in the Y-direction to 0 in step S ₅₈ if. That is, at the time of operation in the Y direction, if the rotation of the motor 43 in that direction is permitted, the motor 43 is driven in that direction, and if not permitted, the state of the first and second limit switches 111, 112 is set. The motor 43 is driven or stopped accordingly.

Further, if the current position of the switching sleeve 84 is not in the X direction side of the target position, if you want to manipulate i.e. in the X direction, the freewheel device 5 shown in FIG. 1 in step S ₅₉
Determines disconnection state of 0, when in the disconnected state is further present position in step S ₆₀ it is determined whether the Y-direction side of the 4WL position. If the 4WL position is on the Y direction side, that is, if it is the 2W position or the first intermediate position α, the above steps S _{54 to} S ₅₈ are executed and the X from the current position is set.
In addition to prohibiting the operation in the direction, the motor 43 is driven in the opposite Y direction depending on the states of the flags F _AY and F _IY . This is to prevent switching from two-wheel drive to four-wheel drive while the freewheel device 50 is disconnected.

Then, when the user wants to operate in the X direction, if the freewheel device 50 is connected and the current position is the 4WL position (or the X direction side from the position) even if the device 50 is disconnected, The rotation flag F _Y in the Y direction is reset to 0 in step S ₆₁ , the value of the rotation permission flag F _AX in the X direction is determined in step S ₆₂ , and if F _AX = 1, the X direction in step S _63. The rotation flag F _X of is set to 1. If F _AX = 0, the value of the X-direction operating force limit flag F _IX is determined in step S ₆₄ , and if F _IX = 0, the X-direction rotation flag F _{X is set} to 1 in step S _63. , F _IX = 1 then the rotation flag F _X is set to 0 in step S ₆₅ . Thus, similarly to the operation in the Y direction, X
If the rotation of the motor 43 in the direction is permitted, the motor 43 is driven in the direction, and if the rotation is not permitted, the first, second
The motor 43 is driven or stopped according to the state of the limit switches 111 and 112.

As described above, the motor 43 is driven and the switching sleeve 84 in the clutch mechanism 41 is slid from the current position to the target position. In that case, the sleeve 84 moves from the 2W position to the 4W position in the X direction. The ON signal of the first limit switch 111 is ignored during the operation in the Y direction from the 4WF position to the second intermediate position β, and the first set value P ₁ By operating with a large operating force of (40 Kg) or more, the switching operation is performed reliably and quickly, and between the other positions, the energization of the motor 43 is stopped by the ON signal of the first limit switch 111. The operating force is set to the first set value P ₁
By being limited to less than 1, the occurrence of switching shock or the like is suppressed.

Next, the determination operation of the synchronization state and the control operation at the time of synchronization failure in steps S ₅ and S ₇ of the flowchart of FIG. 9 which is a characteristic part of the present invention will be described with reference to the flowcharts of FIGS.

First, in the determination operation of the synchronization state shown in FIG.
In steps S ₇₁ and S ₇₂ , the values of rotation flags F _X and F _Y indicating the rotation of the motor 43 in the X and Y directions are determined, and F _X = 1.
If so, the flag F _{XF is set} to 1 in step S ₇₃ , and if F _Y = 1 then the flag F _XF is set to 0 in step S ₇₄ .

Next, determining the value of the flag F _XF in the step S _75, the flag F _XF is running step S ₇₆ from step S ₇₅ when one determines the current position of the switching sleeve 84, and this If the current position is the first intermediate position α, the second limit switch 112 at step S ₇₇ determines whether is ON. If the flag F _XF is not 1,
When the current position of the sleeve 84 is not the first intermediate position α and when the second limit switch 112 is not ON,
In step S ₇₈ to set the set time T ₁ (e.g., 3 seconds) first as a timer value t _1.

On the other hand, when the flag F _XF is 1, the current position of the sleeve 84 is the first intermediate position α, and the second limit switch 112 is ON, that is, the four-wheel drive from the two-wheel drive state of the driver. When switching to the state, the motor
When the sleeve 84 is slid in the X direction by 43 and reaches the first intermediate position α, and the operating force of the motor 43 becomes equal to or greater than the second set value P ₂ (80 kg) at this position, the above-mentioned is performed in step S ₇₉ . The predetermined value Δt ₁ is subtracted from the first timer value t ₁ . And
When the first timer value t ₁ becomes 0 by this subtraction, that is, when the above state continues for the set time T ₁ , steps S ₈₀ to S ₈₁ , S ₈₂ are executed to Two
The synchronization failure flag F _D indicating that synchronization failure has occurred in the synchronization mechanism shown in the figure is set to 1, and in order to prohibit the normal control in step S ₈ of the flowchart of FIG. Y direction rotation permission flag F _AF , F _AY
Are both reset to 0.

In addition, after determining the synchronization failure in this way, steps _S83 and _S84 are executed, and the current position of the sleeve 84 is 2W.
Position or a position other than the first intermediate position α, or the driver cancels the switching operation from the two-wheel drive state to the four-wheel drive state, and again performs the switching operation to the two-wheel drive side. when the target position becomes 2W position, since above-described synchronization failure is resolved, resetting the synchronization failure flag F _D to 0 in step S _85.

In contrast, the synchronization fault condition has continued, if once the operation to return to 2W position side of the motor 43 to the sleeve 84 by the control described later with respect to the this being performed, step from step S _83, S ₈₄ sleeve 84 by running the S ₈₆ is 2W
It is determined whether or not it has returned to the position. Then, before returning to the 2W position, the second timer value t ₂ is set to the set time T ₂ (for example, 3 seconds) in step S ₈₇ , and when returning to the 2W position, the second timer value t _{2 is changed} from the second timer value t _{2 in} step S _88. The predetermined value Δt ₂ is subtracted, and when the second timer value t ₂ becomes 0, step S
_The above step _S85 is executed from ₈₉ to reset the synchronization failure flag F _D to 0. When the flag F _D is reset, the normal control is executed, and the switching operation from the two-wheel drive state to the four-wheel drive state is performed again.

On the other hand, if the synchronization failure is determined as described above, the flag
When F _D is set to 1, control of the out-of-synchronization motor in step S ₇ of the flowchart of FIG. 9 is performed according to the flowchart of FIG.

In this control, first, in steps S ₉₁ and S ₉₂ ,
It is determined whether the second limit switches 111 and 112 are ON. And now, the sleeve 84 is 4W from the first intermediate position α.
When trying to slide to the L position, the motor 43 receives the second set value P
Assuming that a large operating force of ₂ or more is applied, both the first and second limit switches 111 and 112 are in the ON state, so that the value of the first flag F _D1 is determined in step _S93 . . This flag F _D1 is set to 1 in step S ₉₄ when both the first and second limit switches 111 and 112 are OFF, and is 0 at this time, so the second flag F _D2 is next in step S ₉₅ . the on resetting to zero, determines the current position of the sleeve 84 in step S _96. If the sleeve 84 is still located at the first intermediate position α, then the value of the second flag F _D2 is determined in step S ₉₇ , and since F _D2 = 0 at this time, step S ₉₇
The rotation flag F _Y in the Y direction is set to 1 and the rotation flag F _X in the X direction is set to 0 in S ₉₈ and S ₉₉ . As a result, the rotation (energization) of the motor 43 in the X direction is stopped, the motor 43 is rotated in the Y direction, and the sleeve 84 is returned from the first intermediate position α to the 2W position side.

In this way, when the mechanism for returning the sleeve 84 to the 2W position side is started at the time of poor synchronization, the operating force of the motor 43 temporarily decreases and the first and second limit switches 111, 112 are turned off.
Therefore, the first flag F _D1 is set to 1 in step S ₉₄ , and then the second limit switch 11 is set in step S ₁₀₀ .
Determine whether 2 is turned on. When an overload of the second set value P ₂ or more acts on the motor 43 during the return operation, the second flag F _{D2 is set} to 1 in step S _101.
, And then execute steps S ₉₇ to S ₁₀₂ to reset the Y-direction rotation flag F _Y to 0, and set the motor 43
Stop the return operation to the 2W position to protect the.

However, unless an overload of the second set value P ₂ or more is applied during this return operation, the motor 43 rotates in the Y direction and the second
With a large operating force up to the set value P ₂ (80 kg), the sleeve 84 is 2 W
Will be returned to the position.

Thus, as shown in FIG. 17, when the normal four-wheel drive state is switched to the two-wheel drive state, the operating force of the motor 43 reaches the first set value P ₁ (40 Kg) as described above. This prevents the shock from being generated due to the sudden cutoff of the transmission of the driving force to the front wheels, and when the synchronization failure occurs, the sleeve 84 is set to the 2W position before the switching to the four-wheel driving state is completed. If the operation is performed in the same direction as when switching from 4 to 2, the operating force of the motor 43 is set to the second set value P ₂ because the shock does not occur. (80Kg) is allowed, and this return operation will be performed reliably and promptly.

 Next, the operation of the embodiment according to the second invention will be described.

In this embodiment, the first normal operation in the operation force setting operation by the step S ₁₄ of the flowchart of FIG. 10 in the embodiment of the invention is carried out according to the flow chart in FIG. 18, other motor rotation direction The setting operation and the motor control operation are performed in the same manner as in the first embodiment of the invention.

That is, in the operation force setting operation in the embodiment of the second aspect of the invention, step _{S111 in} the flowchart of FIG.
Then, first, it is determined whether or not the sleeve 84 is located at the 4WL position, and when it is located at that position, the position flag F _P is set to 1 in step S ₁₁₂ . The flag F _P, in step S _113, S _114, is reset to 0 when the sleeve 84 is positioned at the 2W position, the sleeve in this state as described above is set to 1 when it is slid to 4WL position It

Next, in step _S115 , the X-direction and Y-direction operation force limit flags F _IX and F _IY are set to 1, and then in step _S116 ,
It is determined whether the second limit switch 112 is ON and O
In the case of N, that is, the operating force of the motor 43 is the second set value P ₂ (80K
In the case of g) or more, set both operation force limit flags F _IX and F _IY to 1
To hold. If the second limit switch 112 is OFF, it is determined in step _S117 whether the first limit switch 111 is ON, and the first limit switch 111 is also OFF.
In other words, if the operating force of the motor 43 is the first set value P ₁
If it is less than (40 Kg), in step S ₁₁₈ , the above X direction and Y
The directional operation force limit flags F _IX and F _IY are both reset to 0. As a result, when the first limit switch 112 is ON, the ON signal prohibits energization of the motor 43 and the operating force is limited to the second set value P _2, and when both limit switches 111 and 112 are OFF, 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.

Further, when the second limit switch 112 is OFF and the first limit switch 111 is ON, that is, the operating force of the motor 43 is in the range from the first set value P ₁ to the second set value P ₂ (40 to 80K).
When in g) determines whether the current position of the sleeve 84 is either from 4WL position Y direction, i.e. the 2W position or the first intermediate position α at step S _119, is at these locations In this case, in step _S120 , the operation force limit flag F _IX in the X direction is reset to 0, the ON signal of the first limit switch 111 is ignored in the X direction, and the operation force is set to the second set value P. Allow electricity until reaching ₂ .

Then, in this 2W position or the first intermediate position alpha, then determines the value of the position flag F _P at step S _121, when F _P = 1, i.e. from the sleeve 84 is 2W position in step S ₁₁₁ When it is determined that the arm has moved to the 4WL position, the Y-direction operation force limit flag F _IY is held at 1 and when F _P = 0, that is, the sleeve 84 is 4W.
When not reached L position, resets the Y direction of the operation force limitation flag F _IY to 0 in step S _122.

Further, in case when the current position of the sleeve 84 is not in the Y direction side of the 4WL position, current position is equal to or a 4WF position in step S _123, in this 4WF position,
In step _S124 , the Y-direction operation force limit flag _FIY is reset to zero.

As a result, as shown in FIG. 19, the ON signal from the first limit switch 111 is ignored at the 2W position and the first intermediate position α in the X direction, as in the first embodiment of the present invention. Further, in the Y direction, the ON signal from the first limit switch 111 is ignored at the 4WF position, and the operating force of the motor 43 and the second limit switch 112 become O at these positions.
The second set value P ₂ (80Kg) that becomes N is allowed and
In other positions, the first limit switch 111
The operating force will be limited by the first set value P ₁ (40Kg) that turns ON. Then, in particular, when the position flag F _P is 0, that is, when the driver performs a switching operation from the two-wheel drive state to the four-wheel drive state, but the switching to the four-wheel drive state is not completed, After that, the switching operation to the two-wheel drive state is performed again, and the sleeve 84 moves from the first intermediate position α to 2W.
When returning to the position, the Y direction operating force limit flag F _IY becomes 0.
(Step _S122 ), the O of the first limit switch 111 is reset as indicated by the (x) mark in FIG.
The N signal is ignored and the operating force of the motor 43 becomes the second set value P ₂
Will be tolerated. Therefore, also in this embodiment, as shown in FIG. 17, as in the case of the first embodiment of the present invention, the two-wheel drive state is set before the switching to the four-wheel drive state in which there is no problem of switching shock is completed. When returning, this returning operation is performed reliably and quickly with a large operating force.

(Effect of the Invention) As described above, according to the present invention, the actuator for operating the switching means for switching between the two-wheel drive state and the four-wheel drive state, and the operating force varying means for changing the operating force by the actuator are provided. In a four-wheel drive vehicle, when the normal four-wheel drive state is switched to the two-wheel drive state, the operating force by the actuator is set to a small value so that the driving force of either the front wheel or the rear wheel is reduced. While the switching shock when the transmission is cut off is suppressed, according to the first aspect of the invention, the actuator is temporarily moved to the two-wheel drive side due to poor synchronization at the time of switching from the two-wheel drive state to the four-wheel drive state. When returning, and according to the second aspect of the invention, after the driver performs the switching operation to the four-wheel drive state and before the switching is completed,
When switching operation to the wheel drive state is performed, these 2
The returning operation to the wheel drive side is performed with a large operation force. That is, when there is no problem of shock at the time of switching from 4 to 2 as described above, the operation from the four-wheel drive side to the two-wheel drive side is performed with a large operation force, and this operation is useless. It will be done promptly without taking time.

[Brief description of the drawings]

1 to 8 show a configuration common to the embodiments of the first and second inventions, and FIG. 1 is a switching control system diagram of a four-wheel drive vehicle,
2 is a cross-sectional view of a main part of a transfer device in the four-wheel drive vehicle, FIG. 3 is a skeleton view of the same, FIG. 4 is a perspective view of an operating force setting mechanism, and FIG. 5 is a perspective view of a main part of the mechanism. FIG. 6 is a front view of a driven gear in the mechanism, FIG. 7 is an operation explanatory view of a position switch, and FIG. 8 is a front view of a driver's seat of the vehicle showing an operation lever. 9 to 17 show the operation of the embodiment of the first invention, FIG. 9 is a flow chart showing a main routine of control operation, and FIG. 10 is a flow chart showing normal control operation. FIG. 11 is a flow chart showing the rotation direction setting operation of the motor, FIG. 12 is a flow chart showing the operation force setting operation, FIG. 13 is an explanatory view of the operation force set by the operation, and FIG. 14 is a motor control. FIG. 15 is a flow chart showing the operation, FIG. 15 is a flow chart showing the judgment operation of synchronization failure, FIG. 16 is a flow chart showing the control operation at the time of synchronization failure, and FIG. FIG. Furthermore, FIGS. 18 and 19 show an embodiment of the second invention.
The figure is a flow chart showing the operation force setting operation similar to that of FIG. 12, and FIG. 19 is an explanatory view of the operation force similar to that of FIG. 41 …… Switching means (clutch mechanism), 43 …… Actuator (motor), 44 …… Operating force varying means (operating force setting mechanism), 60 …… Operating force setting means (controller).

Claims (2)

(57) [Claims] 1. A two-wheel drive state in which only the other wheel is driven and a four-wheel drive state in which the front and rear wheels are driven by connecting and disconnecting the power transmission path to either one of the front wheels or the rear wheels. 2 of a four-wheel drive vehicle that has switching means for switching the switching means, an actuator for operating the switching means, and an operating force varying means for changing the operating force by the actuator.
A switching control device for setting the operating force of the actuator to a small value when switching from the four-wheel drive state to the two-wheel drive state, and at the time of switching from the two-wheel drive state to the four-wheel drive state. When the actuator is temporarily returned from the four-wheel drive side to the two-wheel drive side before the completion of switching to the four-wheel drive state due to poor synchronization between the driving side member and the driven side member of the switching means, the operating force of the actuator is A 2-4 switching control device for a four-wheel drive vehicle, which is provided with an operation force setting means for setting a large value. 2. A two-wheel drive state in which only the other wheel is driven and a four-wheel drive state in which the front and rear wheels are driven by connecting and disconnecting a power transmission path to either one of the front wheels and the rear wheels. 2 of a four-wheel drive vehicle that has switching means for switching the switching means, an actuator for operating the switching means, and an operating force varying means for changing the operating force by the actuator.
-4 The switching control device sets the operating force of the actuator to a small value at the time of switching from the four-wheel drive state to the two-wheel drive state, while the driver switches from the two-wheel drive state to the four-wheel drive state. After the operation, when the switching operation to the two-wheel drive state is performed again before the completion of the switching to the four-wheel drive state, when the actuator returns from the four-wheel drive side to the two-wheel drive side, the actuator A 2-4 switching control device for a four-wheel drive vehicle, comprising an operating force setting means for setting an operating force to a large value.