JPH07186765A - Transfer oil pressure control device for four wheel drive vehicle - Google Patents

Abstract

PURPOSE:To increase control pressure for switching a change over valve into a 2WD mode through a subpump to facilitate its sure supply by comparing the detected value of car speed with its set value for controlling an electric motor to drive the subpump. CONSTITUTION:A oil pressure supply device 4 uses a main pump 20 rotated reciprocally by the output shaft 56 of a speed change gear and a subpump 24 rotated normally by an electric motor 22 for oil pressure source. Working oil in an oil tank 46 is supplied to a variable torque clutch in a transfer 7 at fixed clutch pressure for transmitting driving torque to a front and a rear wheel at fixed distribution ratio. In this case, when control pressure is supplied, a change over valve 40 is switched into a 2WD mode to stop the discharge of the clutch pressure, and on the other hand, when the supply of control pressure is stopped, the change over valve 40 is switched into a 4WD mode to discharge the clutch pressure. In this formation, a control section 5 compares the detected value of car speed with its set value for controlling the driving and stopping of the electric motor 22.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer hydraulic pressure control device for a four-wheel drive vehicle equipped with a transfer capable of controlling a drive force distribution ratio to front and rear wheels, and particularly to a hydraulic oil in a high temperature state or a lapse of time. The present invention relates to a transfer hydraulic control device for a four-wheel drive vehicle that can perform stable hydraulic control of transfer even if it deteriorates.

[0002]

2. Description of the Related Art As a hydraulic power source of a hydraulic pressure supply device mounted on a transfer of a four-wheel drive vehicle, a forward / reverse rotation type main pump which is rotationally driven by being connected to an output shaft (input shaft) of the transmission, and an electric motor. A twin oil pump is known in which a sub-pump that is connected to and is driven to rotate is connected in parallel.

When the vehicle travels at a high speed, a sufficient rotational force can be obtained from the output shaft, so that the hydraulic oil boosted by the main pump is supplied to the variable torque clutch provided in the transfer. It is supplied with the clutch pressure, and the driving force of the rotary drive source is set to
It is distributed and transmitted to the rear wheels. Further, when the vehicle travels at a low speed, a sufficient rotational force cannot be obtained from the output shaft, so that the electric motor is driven and the boosted hydraulic oil is also supplied from the sub pump.

[0004]

By the way, the hydraulic oil used in the hydraulic pressure supply device has a high viscosity due to a long running of the vehicle, resulting in an increase in the amount of leakage, and a decrease in the viscosity due to the deterioration of the hydraulic oil over time. Then, the leak amount may increase. If the amount of hydraulic oil leak changes in this way depending on the running condition of the vehicle, a stable clutch pressure cannot be supplied to the variable torque clutch of the transfer, and high-precision control may not be performed.

Therefore, the present invention has been made by paying attention to the above-mentioned unsolved problems of the prior art, and in particular, it is possible to perform stable hydraulic control of the transfer even when the operating oil is in a high temperature state or deteriorates with time. An object of the present invention is to provide a transfer hydraulic control device for a four-wheel drive vehicle.

[0006]

In order to achieve the above-mentioned object, a transfer hydraulic control system for a four-wheel drive vehicle according to claim 1 of the present invention, as shown in FIG. A forward / reverse rotation type main pump that boosts and discharges the hydraulic oil sucked from the oil tank as a drive source, and a positive pump that is connected in parallel with the main pump and that boosts and discharges the hydraulic oil sucked from the oil tank using an electric motor as a drive source. A rotary sub-pump is used as a hydraulic pressure source, and hydraulic fluid from this hydraulic source is supplied to a variable torque clutch mounted in the transfer at a predetermined clutch pressure, and the variable clutch is brought into a predetermined state so that the rotary drive source Clutch control means for controlling the driving force to be distributed and transmitted to the front and rear wheels at a predetermined distribution ratio, and hydraulic oil adjusted to a predetermined pressure are supplied as control hydraulic pressure. As a result, the switching to the 2WD mode is stopped and the discharge of the clutch pressure to the variable torque clutch is stopped. When the supply of the control pressure is stopped, the restoring force of the spring causes the switching to the 4WD mode and the selection to the variable torque clutch. In a transfer hydraulic control device for a four-wheel drive vehicle equipped with a one-off valve that discharges a predetermined clutch pressure,
An apparatus comprising: a vehicle speed detection means for detecting a vehicle speed of a vehicle; and a motor control means for performing a drive stop control of the electric motor by comparing a detection value of the vehicle speed detection means with a predetermined set vehicle speed. is there.

A transfer hydraulic control device for a four-wheel drive vehicle according to a second aspect is the device according to the first aspect,
An apparatus comprising a vehicle speed correction calculation means for calculating the predetermined set vehicle speed as a minimum vehicle speed at which the electric motor should be driven in order to secure a control pressure at which the switching valve can be switched. A transfer hydraulic control device for a four-wheel drive vehicle according to a third aspect is the device according to the second aspect, further comprising an oil temperature detecting means for detecting an oil temperature of the operating oil, and the vehicle speed correction calculating means has the oil temperature detecting means. An apparatus characterized in that a predetermined set vehicle speed is corrected based on a detection value of a temperature detecting means.

A transfer hydraulic control device for a four-wheel drive vehicle according to a fourth aspect is the device according to the second aspect,
An apparatus comprising: a traveling distance detecting means for detecting a traveling distance of the vehicle, wherein the vehicle speed correction calculating means corrects a predetermined set vehicle speed based on a detection value of the traveling distance detecting means. A transfer hydraulic control device for a four-wheel drive vehicle according to a fifth aspect is the device according to the second aspect, wherein an oil temperature detecting means for detecting an oil temperature of hydraulic oil and a traveling distance detection for detecting a traveling distance of the vehicle. And a means for correcting the predetermined vehicle speed based on the detection values of the oil temperature detecting means and the traveling distance detecting means.

[0009]

According to the transfer hydraulic pressure control device for a four-wheel drive vehicle of claim 1 of the present invention, the motor control means compares the current vehicle speed obtained by the vehicle speed detection means with a predetermined set vehicle speed. Since the drive stop control is performed, the control pressure with which the switching valve is switched to the 2WD mode is boosted by the drive of the electric motor and reliably supplied.

According to another aspect of the present invention, there is provided a transfer hydraulic control system for a four-wheel drive vehicle, wherein the set vehicle speed drives the electric motor so as to secure a control pressure at which the switching valve can be switched by the vehicle speed correction calculation means. Since the vehicle speed is calculated as the lowest possible vehicle speed, even when the vehicle runs in a low speed state in which a sufficient rotational force cannot be obtained from the output shaft, the electric motor is driven to boost the pressure from the sub-pump to reliably supply the vehicle.

According to the transfer hydraulic control device for a four-wheel drive vehicle of the third aspect, the drive stop control of the electric motor is performed in consideration of the decrease amount of the hydraulic pressure due to the increase of the leak amount due to the high temperature state of the hydraulic oil. The predetermined set vehicle speed to be performed can be corrected. Therefore, even if the hydraulic oil is in a high temperature state, the switching valve is reliably switched to the 2WD mode or the 4WD mode to control the clutch pressure supply to the variable torque clutch.

According to another aspect of the present invention, there is provided a transfer hydraulic control device for a four-wheel drive vehicle, wherein an electric motor is considered in consideration of a decrease in hydraulic pressure due to an increase in a leak amount of hydraulic oil that is viscously deteriorated due to an increase in traveling distance. It is possible to correct a predetermined set vehicle speed at which the drive stop control is performed. Therefore, even when the viscosity of the hydraulic oil has deteriorated, the switching valve can reliably operate at 2
The clutch pressure is controlled to be supplied to the variable torque clutch by switching to the WD mode or the 4WD mode.

According to another aspect of the transfer hydraulic control system for a four-wheel drive vehicle of the present invention, there is a decrease in hydraulic pressure due to an increase in the leak amount of the hydraulic oil due to a high temperature state of the hydraulic oil, and a decrease in the viscosity of the hydraulic oil due to an increase in the traveling distance. It is possible to correct a predetermined set vehicle speed at which drive stop control of the electric motor is performed by simultaneously considering the amount of decrease in hydraulic pressure due to an increase in the amount of leak. Therefore, even if the hydraulic oil is in a high temperature state or has undergone viscosity deterioration, the switching valve can reliably operate in the 2WD mode or the 4WD mode.
The supply of the clutch pressure to the variable torque clutch is controlled by switching to the WD mode.

[0014]

Embodiments of the present invention will be described below with reference to the drawings. 1 shows the FR (front engine,
It is a part-time four-wheel drive vehicle based on the rear drive system, with an engine 1 as a rotary drive source and front left
Wheels 2FL to 2RR on the rear right side, a driving force transmission system 3 capable of changing a driving force distribution ratio to the wheels 2FL to 2RR, and a driving force transmission system 3
The vehicle is provided with a hydraulic pressure supply device 4 that supplies a hydraulic pressure to control the drive force distribution by the control device 5, and a control unit 5 that controls the hydraulic pressure supply device 4.

The driving force transmission system 3 changes the driving force from the engine 1 at a selected gear ratio, and the driving force from the transmission 6 to the front wheels 2FL, 2FR and the rear wheels (normal driving wheels). ) 2RL, and a transfer 7 that is divided into two RRs. In the driving force transmission system 3, the front wheel driving force divided by the transfer 7 is applied to the front wheel side output shaft 8, the front differential gear 9 and the front wheel side drive shaft 10.
Is transmitted to the front wheels 2FL and 2FR, while the rear wheel side driving force is transmitted to the rear wheels 2RL and 2RR via the propeller shaft (rear wheel side output shaft) 11, the rear differential gear 12 and the drive shaft 13. It

The hydraulic pressure supply device 4 is configured to supply a hydraulic pressure of a predetermined pressure to the transfer 7 by the circuit configuration shown in FIG. The hydraulic pressure supply device 4 is a forward-reverse rotation type main pump 20 that is directly connected to an input shaft 56a that is connected to the output side of the transmission 6 and is rotationally driven.
And a forward rotation type sub-pump 24 that is arranged in parallel with the electric motor 22 and is rotationally driven using the electric motor 22 as a power source.
The main pump 20 and the sub-pump 24 suck the hydraulic oil in the oil tank 46 through the strainers 20b and 24b, and discharge the hydraulic oil to the discharge side pipes 20c and 24c. Further, a converging pipe 21 that converges the pipes 20c and 24c.
An oil element 26 is connected to a, and a relief passage 30 having the other end connected to the lubrication system 28 side is connected to the upstream side (main pump 20, sub-pump 24 side) of the oil element 26. In addition, the oil element 26
A line pressure regulating valve 32 is connected to the downstream side (transfer 7 side) of the pipe 21b, 2 which branches from the converging pipe 21a.
The input sides of the electromagnetic opening / closing valve 34, the clutch pressure adjusting valve 36, and the pilot valve 38 are connected to 1c, 21d, and 21e, respectively. The output side of the clutch pressure adjusting valve 36 is connected to the input side of a switching valve 40 that switches to the 4WD mode and supplies the clutch pressure Pc to the transfer 7 when the control pressure is not supplied, and the output side of the pilot valve 38. An input side of a three-way solenoid valve (duty control solenoid valve) 42 is connected to. A temperature sensor 43 for detecting the temperature of the hydraulic oil is provided in the oil tank 46, and the output from the hydraulic switch 44 and the switching valve 30 for detecting the pressure set to be reduced by the line pressure regulating valve 32. A pressure switch 45 for detecting the clutch pressure Pc is provided, and these detection signals are output to the control unit 5 described later.

In an actual vehicle, the hydraulic pressure supply device 4 having the above-described circuit configuration is provided inside the chain belt type transfer 7 for transmitting the driving force distribution from the rear wheels to the front wheels shown in FIG. 3 through an endless chain. It is installed in. The transfer 7 has an input shaft 56a inside the transfer casing 50.
Is inserted in a state in which the bearing 54 and the first output shaft 56 are axially supported by the bearing 55, and the input shaft 56a and the first output shaft 56 are connected via a Hi-Low switching mechanism 56c. A wet multi-plate latch (hereinafter, simply referred to as a clutch) 58 for changing the torque distribution ratio to the front and rear wheels is arranged at the center of the first output shaft 56. A first sprocket 60 is connected to a clutch hub 58c of the clutch 58, and is arranged so as to be rotatable with respect to the first output shaft 56. A second output shaft 62, which is arranged in parallel with the first output shaft 56 and is connected to the front wheel side output shaft 8, is rotatably supported by the bearings 63 and 64 below the transfer casing 20. It is inserted in the state. The second sprocket 66 is connected to the second output shaft 62, and the second sprocket 66 is
An endless chain 68 is wound around the sprocket 66 and the first sprocket 60.

The cylinder chamber 58f of the clutch 58
A predetermined clutch pressure P _C is supplied to the input port 70 formed in the transfer casing 50 communicating with the friction plate 58b and the friction disc 58d, which are separated from each other, by generating a pressing force in the cylinder chamber 58f. However, the friction disc 58d comes into contact with the movement of the friction disc 58d, and a fastening force due to a frictional force is applied.
As a result, the rotational driving force corresponding to the clutch pressure P _C is transmitted to the front wheel side via the first sprocket 60, the chain 68 and the second sprocket 66.

The transfer casing 50 is shown in FIG.
As shown in FIG. 5, the front casing 51 is arranged on the front wheel side and the rear casing 52 is arranged on the rear wheel side. The front casing 51 and the rear casing 52 are formed with a flange portion 51a formed on the peripheral portion, 52
The plurality of bolt insertion holes 51b and 52b of "a" are made to correspond to each other, and the connecting bolts 53 are attached to the respective bolt insertion holes to be integrated. The inside of the integrated transfer casing 50 serves as the oil tank 46 of the hydraulic pressure supply device 4.

Here, the inner surface of the rear casing 52 indicated by reference numeral 74 in the drawing is a unit mounting surface on which the control unit 73 described later is mounted, and the outer surface of the rear casing 52 indicated by reference numeral 75 in the drawing is the electric motor 22. Is used as a motor mounting surface. The unit mounting surface 74 and the motor mounting surface 75 are formed so as to be highly parallel to the casing mating surface 52c of the rear casing 52 in order to increase the mounting accuracy of the control unit 73 and the electric motor 22. Has been done.

Inside the rear casing 52,
The control unit 73 (see FIG. 6), the strainer unit 85 (see FIG. 12) integrally provided with the control unit 73, and the buffer plate 90 (mainly intended to prevent the built-in parts from being buffered in the chain 68). (See FIG. 13), and the Hanas component 8 near the terminal portion 82.
Harness cover 83 for protecting 0 (see FIGS. 7 and 8)
Is built in. The oil element 26 is externally attached to the rear casing 52 (see FIG. 15). The main pump 20 that sucks the hydraulic oil from the oil tank 46 has a first gear 71a as shown in FIG.
And the first output shaft 56 via the second gear 71,
The sub-pump 24 is connected to the electric motor 22 externally attached to the transfer casing 50.

The control unit 73 is a unit body in which the valves and sensors shown in FIG. 2 are mounted in valve mounting holes formed in the block-shaped unit main body 76 shown in FIGS. 4 and 5. An oil passage similar to the pipe passage shown in FIG. 2 is formed inside the unit main body 76 to communicate between the valve mounting holes. That is, the unit main body 76
Has valve mounting holes 77a, 77b, 77 on its side surface 76a.
c, 77d, 77e are provided, and the valve mounting hole 77a
To the switching valve 40, the valve mounting hole 77b to the clutch pressure adjusting valve,
The three-way solenoid valve 42 with the solenoid 42d protruding from the side surface 76a in the valve mounting hole 77c, the pilot valve 38 in the valve mounting hole 77d, and the line pressure regulating valve 32 in the valve mounting hole 77e.
Are installed respectively. Further, valve mounting holes 78a and 78b are formed in the center of the upper surface 76b of the unit main body 76, and the hydraulic switch 44 is projected in the valve mounting hole 78a and the solenoid 34d is projected in the valve mounting hole 78b from the upper surface 76b. In this state, the electromagnetic opening / closing valve 34 is mounted. Reference numeral 78c in the drawing is an oil receiving port for the sub-pump 24, and a circular groove 78d in which a lip type packing is fitted is formed on the outer periphery of the oil receiving port 78c. Also, reference numeral 76c
Is a bolt insertion hole used when the unit main body 76 is bolted to the unit mounting surface 74 of the rear casing 52.

The control unit 73 having the above structure is
As shown in FIG. 6, the three-way solenoid valve 42, the solenoid opening / closing valve 34
And a harness component 80 extending from the hydraulic switch 44 and the like are laid on the side surface 76a and the upper surface 76b and fixed, and after the oil temperature switch 43 is further arranged on the upper surface 76b, the unit mounting surface of the rear casing 52 with the pedestal 79 interposed. 74 is abutted and bolted. As a result, the solenoid 34d and the hydraulic switch 44 of the electromagnetic opening / closing valve 34 protruding from the upper surface 76b of the control unit 73 are connected to the chain 6
8 internal spaces. Further, on the side surface 76a of the unit main body 76 from which the solenoid 42d of the three-way solenoid valve 42 is projected, as shown in FIGS. 7 and 8, the pedestal 79 and the unit main body 76 are fixed by bolt connection, and the solenoid 42d. A solenoid fixing plate 81 having a holding hole 81a having substantially the same inner diameter as that of the solenoid 42 is provided.
d is fitted and held in the holding hole 81a.

Here, as shown in FIGS. 7 and 8, each harness component 80 is converged to form the transfer casing 50.
A harness cover 83 is arranged in the vicinity of the terminal portion 82 exposed to the outside. This harness cover 83
Is a support plate 83a, 83b extending from the terminal portion 82 in parallel to the chain 68 side, and a partition plate 83c extending from the tip of the support plate 83a, 83b to the solenoid 42d side in parallel with the winding direction of the chain 68. It consists of and.

Further, as shown in FIGS. 9 and 10, the strainer unit 85 is provided with strainer chambers 86a and 87a, each having a mesh body therein, as separate chambers, and the strainer chambers 86a and 87a have suction ports. 86b and 87b, a main pump discharge port 86c and a sub pump discharge port 87c are provided. The main pump discharge port 86c is formed by the pipe 86d protruding from the unit bottom surface 85a.
The sub-pump discharge port 87c has a lip-type packing attached to the outer peripheral edge thereof. Reference numeral 88 in the drawing denotes a bolt insertion hole used when the strainer unit 85 is bolted to the rear casing 52.

As shown in FIG. 11, in the strainer unit 85 having the above-described structure, a pipe 83d having an O-ring 89a at its base end is fitted into the oil receiving port 57 for the main pump which projects from the inner surface of the rear casing 52. The discharge port 86c for the main pump is made to correspond to the control unit 7
The oil receiving port 78c and the sub pump discharge port 87c of No. 3 are bolted to each other with the lip type packing 89b interposed on the outer peripheral edges thereof, so that the upper portion of the control unit 73 is provided as shown in FIG. Be integrated.

The baffle plate 9 which is a plate-shaped member
As shown in FIG. 13, 0 is arranged between the strainer unit 85 and the chain 68 while covering the entire strainer unit 85, and is bolted to the rear casing 52 at the positions indicated by reference numerals 90a and 90b. Here, when the baffle plate 90 is bolted to the Lee casing 52, the lower surface of the baffle plate 90 is the upper surface 85 of the strainer unit 85.
It comes into contact with b and presses the strainer unit 85 toward the control unit 73 side. This baffle plate 90
13 is provided, the harness component 80 extending from the hydraulic switch 44 and the solenoid 34d of the electromagnetic opening / closing valve 34 toward the chain 68 side is shielded, as shown in FIGS. 13 and 14.

On the other hand, as shown in FIG. 15, the oil element 26 is externally attached to the mounting portion 95 of the rear casing 52 in the direction of arrow A from the outside. The mounting portion 95 is formed with an inflow passage 95a into which the hydraulic oil supplied from the hydraulic source flows and a return passage 95b from which the hydraulic oil is returned from the oil element 26. A step portion 95c is formed on the inner peripheral surface of the attachment portion 95, and a small-diameter feedback communicating with the drain (open to the atmosphere) is provided at a predetermined position of the side peripheral surface 95d facing the outside of the step portion 95c. Road 9
One end of 5e is open.

On the other hand, the oil element 26 is connected to the connecting portion 2
6a, an oil filter filter portion 26b fixed to the connecting portion 26a, an element cover 26c that covers the entire oil filter portion 26b, and a flange portion 26d that liquid-tightly fixes the connecting portion 26a and the element cover 26c to the mounting portion 95. It consists of and. Then, the connecting portion 26a
Is a large diameter portion 26 corresponding to the step portion 95c of the mounting portion 95.
e and a small-diameter portion 26f are formed, and O-rings 26g and 26h are attached to the circumferential grooves formed in these circumferential directions.

Therefore, the hydraulic pressure supply device 4 arranged inside the transfer 7 has the following operational effects. First, the control unit 73 in which the solenoid 34d of the electromagnetic opening / closing valve 34 and the hydraulic switch 44 are provided in a protruding manner.
The input shaft 62 and the output shaft 6 which are arranged in parallel with each other.
With the solenoid 34d and the hydraulic switch 44 arranged in the winding space of the chain 68 wound around 6,
Since the chain 68 is built in the transfer casing 50 apart from the winding position, the layout of the transfer casing 50 can be efficiently performed and the hydraulic pressure supply device 4 can be downsized.

Secondly, the rear casing 52 which constitutes the transfer casing 50 is the control unit 7
3, the unit mounting surface 74 on which the electric motor 22 is mounted, the motor mounting surface 75 on which the electric motor 22 is mounted, and the casing mating surface 52.
Since c is designed to be a plane parallel to each other, when machining with a device such as a milling machine, the machining surface is continuously machined by feeding the rear casing 52 in a predetermined direction. Therefore, the workability of the transfer casing 50 can be improved.

Thirdly, a partition plate 83c for shielding the harness parts from the chain 68 is provided near the terminal portion 82.
Since the harness cover 83 having the above is arranged, it is possible to prevent buffering with the chain 68 even if the harness component 80 moves. Fourthly, the three-way solenoid valve 42 mounted on the control unit 68 has the first output shaft 56 (or the second output shaft 6).
Since the solenoid 42d is arranged so as to project in the direction orthogonal to the axis of 2), it is possible to reliably prevent buffering with the chain 68.

Fifth, when the strainer unit 85 is mounted in the transfer casing 50, the oil receiving port 57 formed in the rear casing 52 and the main pump discharge port 86c of the strainer unit 85 are abutted with each other. The O-ring 89a is in close contact therewith, and the lip type packing 89b is also in close contact with the butting portion between the oil receiving port 78c of the control unit 68 and the sub pump discharge port 87c of the strainer unit 85. Therefore, the hydraulic oil delivery structure between the strainer unit 85 and another hydraulic device can have a structure in which liquid tightness is ensured.

Further, the error in the distance L (see FIG. 10) between the main pump discharge port 86c and the sub pump discharge port 87c is corrected by the oil receiving port 78 with the lip type packing 89b interposed.
Since it can be compensated for by the surface contact structure between the sub-c and the sub-pump discharge port 87c, the strainer unit 85 can be easily and surely mounted in the rear casing 52 without increasing the dimensional accuracy and forming the strainer unit 85. It can be carried out.

Sixth, since the baffle plate 90 is mounted between the strainer unit 85 and the chain 68, the harness part 80 extending from the hydraulic switch 44 and the solenoid 34d of the electromagnetic opening / closing valve 34 contacts the chain 68. Is reliably prevented, and at the same time, the fluctuation of the hydraulic oil level in the oil tank due to the rotation of the chain 68 is suppressed to prevent bubbles from being generated in the hydraulic oil, which may adversely affect the main pump 20 and the sub pump 24. Absent.

When the baffle plate 90 is attached to the rear casing 52, the strainer unit 85
Is pressed to the control unit 72 side, so that the warp of the strainer unit 82 due to the reaction force of the lip-type packing 89b interposed between the oil receiving port 78c of the control unit 73 and the sub-pump discharge port 87c of the strainer unit 85 is prevented. be able to.

Furthermore, even if the mounting bolts of the control unit 73 are loosened by vibration, the baffle plate 90 prevents the mounting bolts from contacting the chain 68 and the mounting bolts. Seventh, the oil element 26 externally attached to the mounting portion 95 of the rear casing 52 is mounted by applying excessive pressure to the connecting portion 26a of the oil element 26 by the high-pressure hydraulic fluid flowing into the oil element 26 from the inflow passage 95a. Even if a gap is generated in the axial direction (coupling direction A) between the portion 95 and the coupling portion 26a, double O-rings 26g and 26h are attached to the outer periphery of the coupling portion 26a at predetermined intervals in the axial direction. Therefore, O-ring 26g due to the generation of gap,
The sealing effect of 26h does not change, so there is no risk of oil leakage. Also, one O-ring 26g
Even when an oil leak occurs in the oil, the oil can be returned from the feedback path 95e to the inflow path 95a.

Next, returning to FIG. 2, each component of the hydraulic pressure supply device 4 will be described in detail. Main pump 2 for normal rotation drive
0 is a strainer 2 connected to the end of the suction pipe 20a
0b from the oil tank 46, the sub-pump 24 also sucks hydraulic oil from the oil tank 46 via the strainer 24b connected to the end of the suction pipe 24a. Then, the check valves 20d and 20d are respectively provided in the discharge pipes 20c and 24c of the respective pumps connected to the converging pipe 21a.
A bypass passage 48 is connected between the discharge pipe 20c of the main pump 20 and the suction pipe 24a of the sub-pump 24 while 24d is interposed. The bypass line 48 includes the bypass pipe 48a and the bypass pipe 4
8a and three check valves 48b interposed, and when the discharge pipe 20c is in a negative pressure state, the check valve 48b is in an open state, and a communication passage through which hydraulic oil flows in the direction of a broken line is provided. Become.

The relief passage 30 connected to the converging pipe 21a on the upstream side of the oil element 26 has a relief pipe 30a whose other end is connected to the lubricating system 28 side, and two relief pipes 30a inserted in the relief pipe 30a. Check valve with spring 30b
It consists of and. Then, the filter of the oil element 26 is clogged, and the oil element 26
When the pressure on the upstream side exceeds a predetermined pressure, the check valve 30b
Becomes an open state and becomes a communication passage through which the hydraulic oil flows in the direction of the broken line arrow.

The line pressure regulating valve 32 is composed of an internal pilot and a pressure reducing valve of the spring type, and the convergent pipe 2
Internal pilot ports 32 _P1 , 3 to which primary pressure and secondary pressure are supplied via an input port 32 _A connected to the 1a side, an output port 32 _B connected to the lubricating system 28 side, and a fixed throttle.
A spool is slidably disposed in a tubular valve housing having 2 _P2, and a return spring 32a that biases the spool toward one end is disposed. The supply pressure P _L increased by the main pump 20 or the sub pump 24 is set to a predetermined pressure by the line pressure adjusting valve 32 and supplied to the electromagnetic opening / closing valve 34, the clutch pressure adjusting valve 36, and the pilot valve 38. The hydraulic oil flowing out from the output port 32 _B when the pressure reduction is set is returned to the lubricating system 28.

Further, the clutch pressure adjusting valve 36 has an internal
It is composed of an external pilot and a spring type pressure control valve, and is connected to the pipe 21c by an input port 36 _A ,
An output port 36 _B connected to the switching valve 40, an internal pilot port 36 _P1 to which the secondary pressure is supplied as a pilot pressure via a fixed throttle, and an external pilot port 36 _P2 to which the control pressure is supplied from the three-way solenoid valve 72. A spool is slidably disposed in a tubular valve housing having a return spring 36a for biasing the spool toward one end. In the clutch pressure adjusting valve 36, when the control pressure is not supplied from the three-way solenoid valve 42, the communication passage between the input port 36 _A and the output port 36 _B is closed and the secondary pressure is not output. When the control pressure is supplied from the three-way solenoid valve 42, the secondary pressure output from the output port 36 _B by controlling the movement of the spool becomes the increased / decreased clutch pressure Pc.

The pilot valve 38 includes an internal pilot and
It is composed of a spring type pressure reducing valve, and piping 2
Input port 38 connected to 1e_A3-way solenoid valve 42
Output port 38 to connect_B, Output port 38_BTwo from
Secondary pressure is supplied as pilot pressure via fixed throttle
Internal pilot port 38_PAnd the drain port 38 _H
Spool is slidable in a tubular valve housing with and
Is arranged in the return and urges this spool toward one end.
A spring 38a is provided. And inside pie
Lot Port 38_PBy the pilot pressure supplied to
Input is performed by controlling the spool to move to a predetermined position.
Port 38_AThe primary pressure supplied from the
It is supplied to the 3-way solenoid valve 42 as a regulated control pressure.
Growling.

A 3-port 2-position proportional solenoid control valve is also used.
The 3-way solenoid valve 42 formed is connected to the pilot valve 38 side.
Input port 42 continued_AAnd connected to the drain side
Drain port 42_RAnd outside the clutch pressure adjusting valve 36
Part pilot port 36_P2Output port 42 to connect with_B
And a spool disposed inside the valve has an output port 4
Two_BAnd drain port 42_RA first position 42 connecting with
b and the input port 42 _AAnd output port 42_BConnect with
The valve is controlled to move to the second position 42c. That
The control signal from the control unit 5 to the solenoid 42d at a predetermined cycle.
No. (command current) CS₀Is supplied, the return spring
From the first position 42b to the second position 42c against the ring 42a.
The spool is controlled to move and a predetermined control pressure is output.
It This allows the external pilot port 36_P2To control pressure
Is supplied, it is discharged from the clutch pressure adjusting valve 36.
As for the clutch pressure Pc, the distribution ratio of the driving torques of the front and rear wheels is “5”.
It increases until it becomes "0:50".

The spring-offset solenoid valve 34 has an input port 34 _A to which line pressure is supplied,
An output port 34 _B connected to the external pilot port 40 _P1 of the switching valve 40 and a drain port 34 _R connected to the drain side are provided, and the spool disposed inside the valve has an input port 34 _A and an output port 34 _B. Is a valve that is controlled to move to a first position 34b that communicates with and a second position 34c that communicates the output port 34 _B and the drain port 34 _R. Then, when the control signal CS ₁ is output from the control unit 5 to the solenoid 34d, the spool is moved and controlled against the return spring 34a to the second position 34c,
The control pressure is not supplied to the external pilot port 40 _P1 of the switching valve 40. When the control signal CS ₁ from the control unit 5 is turned off, the return spring 34a returns the pressure to the first position 34b and the control pressure is supplied to the external pilot port 70 _P1 .

Further, as shown in FIG. 16, the switching valve 40 includes an input port 40 _A to which the secondary pressure is supplied from the clutch pressure regulating valve 36, an output port 40 _B to supply the secondary pressure to the transfer 7, Solenoid 34d of solenoid valve 34
External pilot port 40 _P1, line pressure regulating valve 32 to a more regulated pressure external pilot port 40 _P2 which the line pressure is supplied as a control pressure via a pipe 21d but the control pressure is supplied when a non-energized state, Drain port 40
_{In the} cylindrical valve housing 40i having _H , the spool 4
0e is a valve in which a return spring 40a for urging the spool 40e toward one end is provided. The control pressure from the external pilot port 40 _P1 is supplied in the same direction as the pressing force of the return spring 40a.

The spool 40e of the switching valve 40
_Indicates that the control pressure is not supplied to the external pilot ports 40 _P1 and 40 _P2 , or the external pilot port 4
When the same control pressure is supplied from 0 _P1 and 40 _P2 ,
4W where the input port 70 _A and the output port 40 _B communicate with each other
The movement is controlled to the D mode position 40b (left half sectional state of FIG. 16).

Further, the norenoid 34d of the electromagnetic opening / closing valve 34
Is energized (ON state), the spool of the electromagnetic on-off valve 34 is controlled to move to the second position 34c, whereby
The hydraulic oil supplied to the external pilot port 40 _P1 is returned to the drain side, and the spool 40e becomes the input port 40
2WD mode position 4 in which _A and output port 40 _B are blocked
The movement is controlled to 0c (right half sectional view in FIG. 16).

On the other hand, as shown in FIGS. 1 and 2, the control section 5 stores the detection signals input from a plurality of sensors arranged in the vehicle and the storage stored in a storage section (not shown). The three-way solenoid valve 42, the solenoid on-off valve 34, and the electric motor 22 are drive-controlled by performing arithmetic processing to be described later based on the table, and an operation signal is sent to the alarm circuit 100 when the hydraulic pressure supply device 4 is abnormal. It has a configuration for sending.

As the sensors, the above-mentioned hydraulic switches 44 and 45 and the oil temperature sensor 43 for detecting the oil temperature signal T _n of the working oil in the oil tank 46 are provided, and the traveling distance sensor 101 is used. Mileage signal L _n ,
The vehicle speed signal V _n from the vehicle speed sensor 102 and the mode signal D _n of 2WD or 4WD from the 2-4WD mode sensor 103 are input to the control unit 5 at any time. As shown in FIG. 3, the vehicle speed sensor 102 receives the vehicle speed signal V _n from the speedometer pinion 59b that is meshed with the first output shaft 56 via the third gear 59a.
Information is available.

When the vehicle is running in the 4WD mode,
When stopping or moving backward in the neutral state, 2
In the WD mode, when the vehicle travels forward at a low speed (10 to 20 km / h), a drive signal is sent from the control unit 5 to the electric motor 22 to secure the hydraulic pressure from the sub pump 24. On the other hand, when the vehicle travels forward at a high speed in the 2WD mode, the rotational driving force of the first output shaft 56 can be sufficiently obtained to secure the hydraulic pressure, so that the control unit 5 drives the electric motor 22. Only the main pump 20 is rotationally driven by stopping the signal.

Further, in this embodiment, the switching valve 40 is 4WD.
Although the control pressure is supplied to perform the switching operation from the mode to the 2WD mode, the switching valve 4 is stored in the storage unit of the control unit 5.
The first output shaft 56 that generates a control pressure capable of switching operation of 0
Vehicle speed (control reference vehicle speed) V corresponding to the rotational driving force of the vehicle
Is remembered. Further, the storage unit stores a storage table for correcting the control reference vehicle speed V as shown in FIGS. 17 and 18. That is, the storage table of FIG. 17 stores the characteristics of the vehicle speed correction value ΔV ₁ necessary for compensating for the leak amount caused by the increase in the oil temperature, corresponding to the change in the oil temperature. Further, the storage table of FIG. 18 stores the characteristics of the vehicle speed correction value ΔV ₂ required for compensating for the amount of leak that occurs due to the increase of the traveling distance of the vehicle, corresponding to the traveling distance.

Next, the operation of the hydraulic circuit device of this embodiment according to the running state of the vehicle will be described. When the key switch is turned on, the power is turned on and the control by the control unit 5 is started. Then, the control unit 5 executes the electric motor drive control shown in FIG. 20 by the timer interrupt process at every predetermined time.

In step S1 of this figure, the control unit 35
If it is determined by the information D _n obtained from the 2-4WD mode sensor 103 that the vehicle is in the 2WD mode, the process proceeds to step S2. In step S2, the current oil temperature T _n detected by the oil temperature sensor 43, the current vehicle distance L _n detected by the travel distance sensor 101, and the current vehicle speed V _n detected by the vehicle speed sensor 102. Read the signal.

Next, at step S3, the vehicle speed correction value ΔV ₁ corresponding to the oil temperature signal T _n of the hydraulic oil is determined by referring to the storage table shown in FIG. Then
In step S4, the vehicle speed correction value ΔV corresponding to the distance signal L _n is referred to by referring to the storage table shown in FIG.
Decide on ₂ . Next, in step S5, a corrected vehicle speed (motor drive vehicle speed) NV at which the electric motor 22 should be driven is calculated based on the control reference vehicle speed V by the following formula. NV = V + ΔV ₁ + ΔV ₂ (1) Next, in step S6, it is determined whether or not the vehicle speed V _n at the present time exceeds the calculated motor-driven vehicle speed NV. When the vehicle speed V _n exceeds the motor-driven vehicle speed NV, the process proceeds to step S10, and when the vehicle speed V _n is equal to or less than the motor-driven vehicle speed NV, the process proceeds to step S7.

Next, in step S7, the electric motor 2
It is determined whether or not the status flag F indicating whether 2 is a driving state or a stopped state is "0", and when the flag F is reset to "0" (stopped state), the process proceeds to step S8. When the shift is made and the flag F is "1" (driving state), the program is ended. In step S8, the control unit 5 outputs an operation signal to the electric motor 22,
Close the normally open setting t of the motor relay 22a to close the electric motor 2
2 is energized. Then, in step S9, the flag F is set to "1".

On the other hand, in step S10, it is determined whether or not the flag F is "1", and when the flag F is reset to "0", the program is ended. If the flag F is "1", the process proceeds to step S11. Next, in step S11, the control unit 5
The output of the operation signal to the electric motor 22 is stopped, the normally open setting t of the motor relay 22a is opened, and the electric motor 22 is de-energized. Then, in step S12, the flag F is reset to "0" and the program ends.

As a result, even when the 4DW mode is switched to the 2WD mode and the vehicle is traveling in a low speed state where the rotational driving force of the first output shaft 56 is not sufficiently obtained, the control reference vehicle speed V set in advance is set. Is corrected on the basis of a vehicle speed correction value ΔV ₁ for compensating a leak amount caused by an increase in oil temperature and a vehicle speed correction value ΔV ₂ for compensating a leak amount caused by an increase in the traveling distance of the vehicle. Is calculated, and the sub-pump 23 is driven by the drive and stop control of the electric motor 22 based on the motor drive vehicle speed NV. Therefore, for example, the hydraulic oil becomes a high temperature state, and further, the viscosity of the hydraulic oil deteriorates due to the increase of the traveling distance. Even if the hydraulic oil leak amount of each valve is increased by the above, the sub-pump 24 sufficiently secures the hydraulic pressure and the control pressure to the switching valve 40 sharply decreases. Constant pressure is supplied place without a.

In the electric motor drive control process of FIG. 20, the processes of steps S1 to S5 correspond to the vehicle speed correction calculation means, and the processes of steps S6 to S12 correspond to the motor control means. In addition, the control unit 35
When an operation signal is output from the electric motor 22 to the electric motor 22, the normally open contact t of the motor relay 22a is closed and the electric motor 22 is energized. Inhaled,
Gradually boosted to the line pressure P _L corresponding to the rotational speed of the electric motor 22. Further, the first output shaft 5 is moved by the forward traveling of the vehicle.
By the driving force obtained from 6, the main pump 20 also sucks the hydraulic oil in the oil tank 46 to a predetermined line pressure P _L.
Boost up to. Then, the line pressure P _L is reduced to a predetermined pressure value by the line pressure regulating valve 32 via the oil element 24, and is supplied to the primary side of the clutch pressure regulating valve 36 and the pilot valve 38.

Here, when the hydraulic pressure supply device 4 is operated in a state where foreign matter such as minute dust and rust is mixed in the hydraulic oil, the upstream pressure of the oil element 26 rises and the relief passage 30 moves. The check valve 30b is opened and a communication passage in the direction of the broken arrow is formed. As a result, the relief passage 25 is provided, so that the oil element 26
Foreign matter in the hydraulic oil is prevented from entering the line pressure regulating valve 32 on the further downstream side and the other valves.

Next, when the vehicle selects the 2WD mode and travels forward, the control signal CS ₁ is output from the control unit 5 to the solenoid 34d of the electromagnetic opening / closing valve 34, and the line pressure P of the line pressure regulating valve 32 is output. _L is supplied as control pressure to the external pilots 40 _P1 and 40 _P2 side of the switching valve 40 via the pipes 21b and 21d, but since the electromagnetic opening / closing valve 34 is in communication with the drain side, the external pilot 40 _P2 Only the control pressure is supplied, the input port 40 _A and the output port 40 _B are closed, and the switching valve 40 enters the 2WD mode. This allows
With the friction plate 58b and the friction disc 58d of the clutch 58 separated from each other, the drive torque distribution ratio of the front and rear wheels is set to "0: 100".
The driving force from is transmitted to the rear wheels (normal driving wheels) 2RL, 2RR, and the vehicle runs in the rear two-wheel drive state.

Next, when the vehicle selects the 4WD mode and travels forward, the control unit 5 stops the output of the control signal to the solenoid 34d of the solenoid opening / closing valve 34, and the three-way solenoid valve 42 operates. The control signal CS ₀ having a predetermined cycle is supplied to the solenoid 42d. As a result, the three-way solenoid valve 42 supplies a predetermined control pressure to the clutch pressure adjusting valve 36, and the clutch pressure adjusting valve 36 moves to the output port 36.
The clutch pressure Pc of a predetermined pressure is discharged from _B. Also,
Since the control pressure is supplied to the external pilot port 40 _P1 of the switching valve 36 to which the clutch pressure Pc is supplied to the primary side, the input port 40 _A and the output port 40 _B communicate with each other, and the drive torque distribution ratio of the front and rear wheels is increased. The clutch pressure Pc that increases until is 50:50 is supplied to the transfer 7.

Next, when the vehicle runs backward, an operation signal is transmitted from the control section 5 and the electric motor 22 is energized. Then, when the main pump 20 is driven in the reverse rotation, the suction side of the main pump 20, that is, the pipe 20c side is in a negative pressure state, whereby the three check valves 48b connected to the bypass pipe 48a are opened.
The main pump 20, which is driven in the reverse direction, transfers the hydraulic oil in the oil tank 46 to the strainer 24 b of the sub pump 24.
From the suction pipe 20a through the bypass passage 48.
And passes through the strainer 20b and returns into the oil tank 46.

As a result, when the main pump 20 is driven in the reverse direction, the strainer 2 which is the discharge port of the main pump 20.
Even if bubbles occur around 0b, strainer 24b
Since the main pump 20 can be driven by sucking only the working oil without sucking bubbles from the strainer 24b of the sub-pump 24 which is arranged in the oil tank 46 while being separated from the main pump 20, the aeration of the main pump 20 is suppressed. To be done.

Therefore, according to the present invention, even when the hydraulic pressure supply device 4 is operated in a state in which foreign matter such as minute dust or rust is mixed in the hydraulic oil, the pressure on the upstream side of the oil element 26 increases and the reverse pressure of the relief passage 30 is reversed. The stop valve 30b is opened, and a communication passage in the direction of the broken line arrow is formed, and the relief passage 25 is formed.
By disposing, the foreign matter in the hydraulic oil is prevented from entering the line pressure regulating valve 32 and other valves downstream of the oil element 26, and the durability of the hydraulic pressure supply device 4 can be improved. it can. Further, when the filter of the oil element 26 is clogged, the working oil is supplied to the lubricating system 28 by the communication path of the relief path 30 in the direction of the broken line, so at least from the standpoint of fail-safe, It is possible to ensure traveling in the two-wheel drive state.

When the main pump 20 is driven in the reverse direction when the vehicle is traveling in reverse, the suction side of the main pump 20, that is, the pipe 20c side is in a negative pressure state, so that the three check valves 48b are opened. The main pump 20 that is driven in the reverse direction supplies the hydraulic oil in the oil tank 46 to the
From the strainer 24b of the sub pump 24 to the bypass 48
Suction through the suction pipe 20a and strainer 20b
When the main pump 20 is driven in the reverse direction, even if bubbles are generated around the strainer 20b which is the discharge port of the main pump 20, the main pump 20 is separated from the strainer 24b and separated from the oil tank. The main pump 20 can be driven by sucking only the hydraulic oil without sucking bubbles from the strainer 24b of the sub-pump 24 disposed inside the pump 46, suppressing the aeration of the main pump 20, and improving the durability of the pump. Also, the sound and vibration performance can be improved.

Also, the 4DW mode is switched to the 2WD mode.
It is possible to obtain sufficient rotation driving force for the first output shaft 56 by selecting
Even when traveling at low speed
The control reference vehicle speed V is the leak amount caused by the increase in the oil temperature.
Vehicle speed correction value ΔV₁And increase the mileage of the vehicle
Vehicle speed correction value ΔV that compensates for the amount of leakage caused by ₂
The motor drive vehicle speed NV is calculated by correction based on
Of the electric motor 22 based on the motor drive vehicle speed NV of
Since the sub-pump 23 is driven by the motion and stop control,
For example, hydraulic oil becomes hot, and
Of the hydraulic oil due to the increase in
The sub-pump 24
Ensures sufficient hydraulic pressure and the control pressure to the switching valve 40 suddenly increases.
It is possible to supply a predetermined pressure without decreasing, and
Providing a hydraulic pressure supply device with improved control response from dynamic to two-wheel drive
Can be offered.

Next, a second embodiment of the present invention will be described with reference to FIG. In this embodiment, when the vehicle traveling forward in the 4WD mode is switched and selected to the 2WD mode, the control unit 5 performs a timer interrupt process at predetermined time intervals shown in FIG. Executed as adjustment control. In step S1 of this figure, the control unit 5
Is 2W by the 2-4WD mode sensor 103
If it is determined that the D mode is selected, step S
It shifts to 2.

In step S2, the current vehicle speed V _n signal is read from the vehicle speed sensor 102. Next, in step S3, it is determined whether or not the vehicle speed V _n at the present time exceeds the control reference vehicle speed V. When the vehicle speed V _n is _equal to or higher than the control reference vehicle speed V, the process proceeds to step S4,
When the vehicle speed V _n is lower than the control reference vehicle speed V, the process proceeds to step S6.

Next, in step S4, the command current I _SOL corresponding to the maximum clutch pressure Pc at which the distribution ratio of the front and rear wheels driving torque becomes "50:50" is determined. Then
In step S5, a control signal corresponding to the value of the command current value I _SOL determined in step S4 is output to the three-way solenoid valve 42, and the process returns to the main program. By this control, the control pressure of the three-way solenoid valve 42 is controlled by the control signal output from the control unit 5 to the three-way solenoid valve 42.
6, the secondary pressure of the clutch pressure adjusting valve 36 is adjusted to the maximum clutch pressure Pc at which the drive torque distribution ratio of the front and rear wheels becomes “50:50”.

On the other hand, in step S6, the command current value I _SOL corresponding to the minimum clutch pressure Pc (for example, the clutch pressure Pc that puts the clutch in the standby state immediately before the engaged state) is determined. Next, in step S5, a control signal corresponding to the command current value I _SOL determined in step S6 is output to the three-way solenoid valve 42, and the process returns to the main program. By this control, the control pressure of the three-way solenoid valve 42 is supplied to the clutch pressure adjusting valve 36 by the control signal output from the control unit 35 to the three-way solenoid valve 42, and the secondary pressure of the clutch pressure adjusting valve 27 is supplied. Is adjusted to the clutch pressure Pc in which the clutch 58 is in the standby state immediately before the engagement state.

Therefore, when the vehicle is switched and selected from the 4DW mode to the 2WD mode, at the vehicle speed V _n below the control reference vehicle speed V at which the rotational driving force of the first output shaft 56 is not sufficiently obtained, the clutch pressure adjusting valve 36 becomes Minimum clutch pressure Pc
Is controlled by the three-way solenoid valve 42 via the control unit 5 so as to output as the secondary pressure, the input port 40 _A and the output port 40 _B of the switching valve 40 are reduced due to the decrease in the control pressure. Even if they are communicated with each other, the amount of hydraulic oil flowing into the clutch 58 is very small, and there is no fear that the clutch 58 will generate a tight corner.

Further, when the vehicle speed V _n is _{equal to} or higher than the control reference vehicle speed V, the clutch pressure adjusting valve 36 causes the maximum clutch pressure Pc to rise.
Is controlled by the three-way solenoid valve 42 via the control unit 5 so as to output as the secondary pressure. Therefore, when the vehicle is switched from the 2WD mode to the 4DW mode, the control from the two-wheel drive to the four-wheel drive is performed. A hydraulic pressure supply device with improved response can be provided.

In the pressure adjustment control process of FIG. 21, the processes of steps S1 to S3 correspond to the vehicle speed determination means, and the processes of steps S4 to S6 correspond to the pressure adjustment valve control means. In addition, in the above-mentioned embodiment, the four-wheel drive vehicle based on the rear-wheel drive vehicle has been described, but the present invention is not limited to this. The same applies to a four-wheel drive vehicle based on the front-wheel drive vehicle. The effect can be obtained.

[0074]

As described above, according to the transfer hydraulic pressure control device for a four-wheel drive vehicle according to claim 1 of the present invention, the motor control means has the current vehicle speed obtained by the vehicle speed detection means and a predetermined value. Since the drive stop control of the electric motor is performed based on the comparison with the set vehicle speed, the control pressure at which the switching valve switches to the 2WD mode can be reliably supplied by boosting the control pressure by the sub pump by driving the electric motor.

According to the transfer hydraulic control device for a four-wheel drive vehicle of the second aspect, the set vehicle speed drives the electric motor to secure the control pressure at which the switching valve can be switched by the vehicle speed correction calculation means. Since it is calculated as the lowest possible vehicle speed, even if the vehicle runs in a low speed state where sufficient rotational force cannot be obtained from the output shaft, it can be boosted by the sub pump by the electric motor drive and reliably supplied. .

According to the transfer hydraulic control system for a four-wheel drive vehicle of the third aspect, the drive stop control of the electric motor is controlled in consideration of the decrease amount of the hydraulic pressure due to the increase of the leak amount due to the high temperature state of the hydraulic oil. Since the predetermined set vehicle speed to be performed can be corrected, the switching valve is reliably switched to the 2WD mode or the 4WD mode to control the supply of the clutch pressure to the variable torque clutch even when the hydraulic oil is in a high temperature state. be able to.

Further, according to the transfer hydraulic control device for a four-wheel drive vehicle of the fourth aspect, the electric motor is considered in consideration of the decrease amount of the hydraulic pressure due to the increase of the leak amount of the hydraulic oil which is viscously deteriorated due to the increase of the traveling distance. Since the predetermined set vehicle speed for performing the drive stop control can be corrected, the switching valve can be reliably switched to the 2WD mode or the 4WD mode even when the hydraulic oil is viscously deteriorated. It is possible to control the supply of the clutch pressure to the clutch.

According to the transfer hydraulic control system for a four-wheel drive vehicle of the fifth aspect, the hydraulic oil is reduced in amount due to an increase in leak amount due to a high temperature state of hydraulic oil, and the viscosity of hydraulic oil is deteriorated due to an increase in travel distance. It is possible to correct the predetermined set vehicle speed that controls the drive stop of the electric motor by simultaneously considering the amount of decrease in the hydraulic pressure due to the increase in the amount of leakage, so that it is possible to detect when the operating oil is in a high temperature state or has a viscosity deterioration. However, the switching valve can be reliably switched to the 2WD mode or the 4WD mode to control the supply of the clutch pressure to the variable torque clutch.

Therefore, according to the present invention, the switching valve can be reliably operated at 2W.
Since the supply of the clutch pressure to the variable torque clutch is controlled by switching to the D mode or the 4WD mode, the four-wheel drive control and the two-wheel drive control can be performed with high accuracy.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an outline of a four-wheel drive vehicle according to the present invention.

FIG. 2 is a block diagram showing a hydraulic pressure supply circuit according to the present invention.

FIG. 3 is a diagram showing a transfer internal structure according to the present invention.

FIG. 4 is a plan view showing a unit body of a control unit according to the present invention.

FIG. 5 is a side view showing a unit body of a control unit according to the present invention.

FIG. 6 is a view showing a state in which a control unit is mounted in a rear casing around which a strip is wound.

FIG. 7 is a plan view showing a harness cover and a three-way solenoid valve according to the present invention.

FIG. 8 is a side view showing a harness cover and a three-way solenoid valve according to the present invention.

FIG. 9 is a plan view showing a strainer unit according to the present invention.

FIG. 10 is a side view showing a strainer unit.

FIG. 11 is a view showing a joined state of the strainer unit and the oil delivery section.

FIG. 12 is a view showing a state in which a control unit and a strainer unit are mounted in the rear casing.

[Fig. 13] Control unit in the rear casing,
It is a figure showing the state where the strainer unit and the baffle plate were attached.

FIG. 14 is a view showing a baffle plate arranged near a hydraulic switch.

FIG. 15 is a cross-sectional view showing a state in which an oil element is externally attached to a part of the rear casing.

FIG. 16 is a cross-sectional view showing a switching valve that constitutes a hydraulic pressure supply device.

FIG. 17 is a diagram showing characteristics of a temperature rise of hydraulic oil and a vehicle speed correction value.

FIG. 18 is a diagram showing the characteristics of the traveling distance of the vehicle and the vehicle speed correction value.

FIG. 19 is a basic configuration diagram showing an outline of a first control means of the present invention.

FIG. 20 is a flowchart showing the first control means of the present invention.

FIG. 21 is a basic configuration diagram showing an outline of a second control means of the present invention.

FIG. 22 is a flow chart diagram showing a second control means of the present invention.

[Explanation of symbols]

 5 Control Section 7 Transfer 20 Main Pump 22 Electric Motor 24 Sub Pump 40 Switching Valve 43 Oil Temperature Sensor 56 Input Shaft (Output Shaft) 58 Variable Torque Clutch 101 Traveling Distance Sensor 102 Vehicle Speed Sensor Pc Clutch Pressure

Claims (5)

[Claims] 1. A forward / reverse rotation type main pump that pressurizes and discharges hydraulic oil sucked from an oil tank using an output shaft that rotates normally and reversely as a drive source, and a main pump that is connected in parallel with the main pump and uses an electric motor as a drive source. A forward rotation type sub-pump that pressurizes and discharges the hydraulic oil sucked from the oil tank is used as a hydraulic pressure source, and the hydraulic oil from this hydraulic source is supplied to the variable torque clutch mounted in the transfer at a predetermined clutch pressure to Clutch control means for controlling the distribution of the driving force of the rotary drive source to the front and rear wheels at a predetermined distribution ratio with the clutch in a predetermined state, and hydraulic oil adjusted to a predetermined pressure as control hydraulic pressure. When the variable pressure clutch is switched to the 2WD mode by being supplied, the discharge of the clutch pressure to the variable torque clutch is stopped, and the supply of the control pressure is stopped. Speed control means for detecting the vehicle speed of a vehicle in a transfer hydraulic control device for a four-wheel drive vehicle, which includes a switching valve that is selected and switched to the 4WD mode by the restoring force of the engine and discharges a predetermined clutch pressure to the variable torque clutch. And a motor control means for performing drive stop control of the electric motor by comparing a detection value of the vehicle speed detection means with a predetermined set vehicle speed, a transfer hydraulic control device for a four-wheel drive vehicle. 2. The transfer hydraulic control device for a four-wheel drive vehicle according to claim 1, wherein the predetermined set vehicle speed is a minimum value for driving the electric motor in order to secure a switchable control pressure of the switching valve. A transfer hydraulic control device for a four-wheel drive vehicle, comprising: a vehicle speed correction calculation means for calculating the vehicle speed of the vehicle. 3. The transfer hydraulic control device for a four-wheel drive vehicle according to claim 2, further comprising an oil temperature detecting means for detecting an oil temperature of the hydraulic oil, wherein the vehicle speed correction calculating means detects the oil temperature detecting means. A transfer hydraulic control device for a four-wheel drive vehicle, which corrects a predetermined set vehicle speed based on a value. 4. The transfer hydraulic control device for a four-wheel drive vehicle according to claim 2, further comprising a traveling distance detecting means for detecting a traveling distance of the vehicle, wherein the vehicle speed correction calculating means has a detection value of the traveling distance detecting means. A transfer hydraulic control device for a four-wheel drive vehicle, wherein a predetermined set vehicle speed is corrected based on the above. 5. The transfer hydraulic control device for a four-wheel drive vehicle according to claim 2, further comprising: an oil temperature detecting means for detecting an oil temperature of hydraulic oil; and a traveling distance detecting means for detecting a traveling distance of the vehicle. The transfer hydraulic control device for a four-wheel drive vehicle, wherein the vehicle speed correction calculation means corrects a predetermined set vehicle speed based on the detection values of the oil temperature detection means and the traveling distance detection means.