JPS61249828A - Drive gear coupling device for four-wheel drive - Google Patents

Abstract

PURPOSE:To prevent the occurrence of a braking phenomenon at the time of low speed, sudden turning without fail, by making an allowable state in revolving speed difference between front wheels and rear wheels so as to be adjustable according to a running state of a car. CONSTITUTION:During car driving at four-wheel drive,when rear wheels cause slip and a revolving speed at the rear-wheel output shaft side is speedier than that at the front-wheel output shaft side, a rotor 69 relatively rotates. With this rotation, oil is sucked in suction and discharge ports 73, 75 and 77 through a second oil passage OL2 from an oil tank 80 by way of a check valve 79, and then discharged out of a check valve 82 with an orifice 82a from suction and discharge ports 72, 74 and 76 of a pump houses 86-88 by way of a first oil passage OL1. Since this discharge pressure is a value corresponding to a revolving speed difference between the rear-wheel output side and the front- wheel output shaft side, size of torque to be transmitted by an oil pump 14 also comes to be varied according to the revolving speed difference.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to a four-wheel drive vehicle in which the front wheels and rear wheels are driven by the same engine, and in particular, the present invention relates to a four-wheel drive vehicle in which the front wheels and the rear wheels are driven by the same engine. This invention relates to a four-wheel drive drive coupling device for a four-wheel drive vehicle, which is equipped with a hydraulic pump type coupling mechanism between the two.

[Conventional technology]

Four-wheel drive (4-wheel drive) in which the front and rear wheels are driven by the same engine.
In 4WD (4WD) cars, there is a slight difference in the effective radius of the front and rear tires, and when turning, the front wheels have a larger turning radius than the rear wheels, so the front and rear wheels are forced to drive in order to turn faster. Torsional torque is generated between the shafts, resulting in the same state as braking, resulting in the so-called tight corner braking phenomenon, which deteriorates driving performance.
This causes wear on the tires, so a means to prevent this is necessary.

For this reason, in conventional four-wheel drive vehicles, in the drive connection part,
The front and rear wheels are connected by a dog clutch, etc.
During cornering, the front and rear wheels rotate at the same speed even though their rotational speeds are different, so brake torque is applied from the rear wheels to the front wheels. In order to reduce this phenomenon, a method has been proposed in which a wet multi-disc clutch is used in the connection part and the clutch slides during cornering to absorb the difference in rotational speed between the front and rear wheels. There was a risk of burnout.

[Problem that the invention seeks to solve]

In such conventional four-wheel drive vehicles that use means to absorb the difference in rotational speed between the front and rear wheels, there is a loose characteristic that allows the difference in rotational speed between the front and rear wheels, and a loose characteristic that allows the difference in rotational speed between the front and rear wheels. It is desirable to switch between tight characteristics that allow only a small amount of

In other words, when starting suddenly, driving on a low μ road, when road conditions suddenly change (such as when changing from a paved road to dirt or snow), or when running onto a curb, the front and rear wheels should be tightened. It is desirable to generate torque from each wheel to create a four-wheel drive state.

In addition, when turning tight corners on high μ roads, when you want to absorb tire radius differences, and when driving in general on high μ roads, torque is generated from either the front or rear wheels as a loose characteristic to create a two-wheel drive state. This is desirable.

However, conventionally, there has been no proposal for switching between such tight characteristics and loose characteristics.

The present invention aims to solve such problems, and is capable of adjusting the permissible state of the rotational speed difference between the front wheels and the rear wheels according to the running condition of the vehicle.
An object of the present invention is to provide a drive coupling device for wheel drive.

[Means for solving problems]

Therefore, the four-wheel drive drive coupling device of the present invention includes a first rotating shaft that transmits the driving force to the front wheels of the vehicle, a second rotating shaft that transmits the driving force to the rear wheels, and the first rotating shaft that transmits the driving force to the rear wheels. axis of rotation and the second
The hydraulic coupling mechanism is configured as a hydraulic pump-type coupling mechanism, and the hydraulic coupling mechanism is configured as a hydraulic pump-type coupling mechanism, and the hydraulic coupling mechanism is interposed between the rotary shaft and the rotating shaft to mutually transmit driving force. Connecting oil passage and suction port of the same connection mechanism (including oil sump)
The communication oil passage that communicates with the oil passage connected to the oil passage, and the flow rate of hydraulic oil passing through the communication oil passage (from zero flow rate to unrestricted flow rate)
A flow rate control mechanism capable of controlling the flow rate control mechanism is provided, and a manual flow rate limit setting means for outputting a control signal for setting the limit flow rate to the flow rate control mechanism 8!1, and a manual flow rate limit setting means for detecting the operating state of the vehicle. The operating state sensor and the flow rate control P11m based on the detection signal from the operating state sensor.
The automatic limiting flow rate setting means outputs a control signal for setting the navel limited flow rate, and the control signal from only one of the above-mentioned manual limiting flow rate setting means and automatic limiting flow rate setting means is selectively output. The present invention is characterized in that a switching mechanism for sending the flow to the flow control mechanism is provided.

[For production]

In the above-mentioned four-wheel drive drive coupling device of the present invention, the switching mechanism selects between control by the manual flow rate limit setting means and control by the automatic flow rate limit setting means. A control signal output to the flow rate control mechanism controls the flow rate of hydraulic oil passing through the communication oil passage.

Accordingly, the differential pressure between the discharge port and the suction port of the hydraulic pump type coupling mechanism or the pressure at the discharge port is controlled, and the torque transmitted by opening the rotation shaft of NS1 and the second rotation shaft is controlled. Ru.

〔Example〕

Hereinafter, embodiments of the present invention will be explained with reference to the drawings.
Figures 1 to 9 show a four-wheel drive drive coupling device as an embodiment of the present invention, Fig. 1 is a hydraulic system diagram showing the hydraulic pump type coupling mechanism and hydraulic circuit, and Fig. 2 is a diagram of the drive coupling device for four-wheel drive as an embodiment of the present invention. A schematic diagram showing the power system of a vehicle equipped with
Figures (,) to (d) are all 70-charts for explaining the action, and Figures 6 to 9 are graphs for explaining the action.

As shown in FIGS. 1 to 3, an automatic transmission IS is applied to the horizontally mounted engine 1 via the torque converter 1a and the input shaft (inner shaft) 142! 2 are connected to each other, and a gear 3' on an intermediate shaft meshes with a gear 3 on an output shaft of the automatic transmission 2, and a gear 38' on one end side of an output shaft 38m meshes with this gear 3'. .

On the other end side of this output shaft 38a, as shown in FIG.
A gear 38 is attached, and this gear 38 meshes with a ring gear 39 of a front wheel differential mechanism 40 (hereinafter referred to as "front wheel differential 40J").
The torque from the front wheel is divided by the front wheel differential 40 and transmitted to the left and right front wheel axles 41.42, thereby rotationally driving the front wheels 43.44.

Side gears 11 and 12 are meshed with the ring gear 39 and the pinions 9 and 10 that are integrated with the differential case 8, and a front wheel shaft 41 is connected to the side gear 11.
A front wheel shaft 42 is connected to the side gear 12.

Also, a gear 39' that meshes with this ring gear 39 is provided, and this gear 39'! It is fixed to the front export force shaft 5 as the rotating shaft of @1.

Further, a 41-wheel drive drive coupling device 13 as a hydraulic pump type coupling mechanism is interposed between the front export force shaft 5 and the rear export force shaft 4 as the second rotating shaft.

Further, the rear export force shaft 4 is the gear 'r4 of the bevel gear mechanism 45.
Transfer propeller shaft 47 via 5a, 46a
The bevel gear 4 of this propeller shaft 47
7a is a rear wheel differential mechanism 49 (hereinafter referred to as "rear wheel differential 49")
) is meshed with the ring gear 48. As a result, the torque from the rear export power shaft 4 is divided by the rear wheel differential 49 and transmitted to the left and right rear wheel shafts 50°51.
3 to rotate.

Further, as shown in Fig. 2.4, a rotation speed sensor (pickup )12
7 is provided, and the detection signal from this sensor 127 is input to the counter 128b of the control unit 128.

A gear 45 of the rear export force shaft 4 as the second rotating shaft
A rotation speed sensor (pickup) 126 as a second rotation speed detector is provided opposite to the teeth of a, and a detection signal from this sensor 126 is input to a counter 128a of a control unit 128. It has become.

These counters 128a, 128b are the timer 128
The count number (detection signal) for each predetermined time width is sent to a computing unit (CPU) 128d, and this computing unit 128d transmits the count number of the front export force shaft 5 to the gear 39 and the gear 39. Using the ratio i to 39'', it is converted to the rotation speed Rf of the front wheel 43.44.

Then, the computing unit 128d calculates the count number of the rear export force shaft 4 by the ratio iB of the gear 45a and the gear 46a and the gear 47.
Using the ratio iD between a and the gear 48, it is converted into the rotation speed Rr of the rear wheels 52°53.

The calculator 128d calculates the difference between the front wheel rotation speed Rf and the rear wheel rotation speed Rr, and displays the difference between the front wheel rotation speed Rf and the rear wheel rotation speed Rr as a display signal on the display device 1.
Output to 29.

Then, the display device 129 receives the display signal, and if the rotational speed difference is O-20 (rpm), L E D 12
Turn on 9a and if the speed is 20-30 (rpm), L E
D 129b is turned on, if the speed is 3030-40 (rp), the LED 129c is turned on, and if it is 40 (rpm) or higher, the LED 129d is turned on.

Further, the control unit 128 is configured to receive a steering angle signal from a steering angle detector (steering angle sensor) 130.
8 and the display device M129 are connected to a warning light 131, so that the warning light 131 can issue an alarm.

This drive coupling W113 includes an oil pump (vane pump) 14 that is driven by a rotational speed difference between the front export force shaft 5 and the rear export force shaft 4 and discharges oil at a pressure corresponding to this rotation speed difference, and this oil pump. A discharge pressure control mechanism (hydraulic circuit) 71 that can suppress the rotational speed difference between the output shafts 4 and 5 by controlling the pressure of the oil discharged from the output shaft 14 is configured.

Next, the arrangement of the oil pump 14 and the discharge pressure control mechanism 71 will be explained.

As shown in FIGS. 1 and 3, an oil pump 14 and a discharge pressure control mechanism 71 are provided within the housing 70.

As shown in FIG. 1, this oil pump (vane pump) 14 has a large number (10 in this case) of holes 69b formed at equal intervals in the circumferential direction on the outer peripheral surface 69a of the rotor 69. A vane 68 that can come into sliding contact with the inner circumferential surface of the cam ring portion Oa is fitted into each of the many holes 69b.

Furthermore, the intervening member 70d of Haukunga 0 and the vane 68
Each part is formed so that the axial clearance with the housing 70 and the vane 68 and the rotor 69 is below a predetermined value, so that the oil film does not break, and the interposition member 70e of the housing 70, the vane 68, and the rotor 69 are connected to each other. Similarly, each part is formed so that the gap in the axial direction is equal to or less than a predetermined value.

The sum of these gaps is set to be less than or equal to a predetermined value.

Further, the vane pump 14 discharges an amount of oil proportional to its rotation speed, and is connected to the rotor 69 and the cam ring part 70.
When a relative rotation occurs between the rear wheel output port 4 and the front output port 5, it functions as a hydraulic pump and generates hydraulic pressure.

Discharge port of the vane pump 14 (suction/discharge lower 2 to 77 at the tip of the relative rotational direction of the vane 68 with respect to the housing 70
(equivalent to this), the rotor 69 and the cam ring portion 70a become like a rigid body and are rotated together by the static pressure via the oil.

Therefore, between the cam ring part 70a and the rotor 69, there are three pump chambers 86 to 86 at intervals of 120 degrees from the rotation center line.
88 is formed, and six suction/discharge lowers 2 to 77 are formed at approximately 120° intervals, which become external suction ports when located on the base end side in the rotational direction and become discharge ports when located on the distal end side. , suction and discharge lowers at 120° intervals that perform the same function 2,
74.76 is the first oil passage OL via the cover 70b of the housing 70, the 7 langes 70c1, the interposers 70cl, and 70e.
, is communicated by.

The suction and discharge lowers 3, 75, and 77 are the cover 70b, 7-run 70c, and intervening material 70d of Haunonga 0.

It is communicated with the second oil passage OL 2 via 70e.

Further, the first oil passage OL and the second oil passage OL 2 are communicated with an oil reservoir (oil tank) 80 at the bottom of the transmission case 94 via check valves 78 and 79, respectively. Only the flow to path OL l-OL 2 is allowed, and the first oil path OL, and @2
Two relief valves 83 and 84 for controlling the discharge pressure are provided between the oil passage OL2 and the oil passage OL2, which cause the oil passages OL and OL2 to communicate with each other when the discharge pressure exceeds a predetermined pressure.

These relief valves 83184 are biased in the closing direction by springs 83a and 84a, respectively.

Check valve 79 and suction/discharge port? A communication passage 89 for relieving the discharge pressure to the oil reservoir 80 is connected to the second oil passage OL between the oil reservoir 80 and the oil reservoir 80. An intrusion prevention check valve 81 is inserted.

Also, check valve 78 and suction/discharge port? 2,74°76
A communication path 90 for relieving discharge pressure to the oil reservoir 80 is connected to the oil path OL of tlSl between the
An air intrusion prevention check valve 82 with an orifice 82a is inserted into this communication path 90.

With such a hydraulic circuit 71, the discharge pressure always acts on the relief valve 83 and the valve body of the relief valve 84, regardless of the relative rotation direction between the rotor 69 and the cam ring part 70a, and the oil reservoir 80 It will communicate with the mouth.

In addition, 7 that constitutes the housing 70 of the vane pump 14
The flange 70c is pivotally supported by a transmission case 94 via a bearing 93, and the rear wheel output port 4, which is integral with the cover 70b, is attached to the bearing portion (
(not shown) is pivotally supported by the transmission case 94.

Spline engagement portion 64 on rotor 69 of vane pump 14
The front export force shaft 5 connected via a has bushings (bearings) 95.9 on both sides of the spline engagement portion 64a.
6, and are pivotally supported by the cover 70b and the interposer 70e, respectively.

The bottom portion 68b of the vane 68 is an oil passage OL.

The oil passage on the discharge side of the OL (here, the first oil passage OL
, ) is reduced through the flow path 121 (120) with the check valve 123 (122), and the tip portion 68a of the vane 68 is urged toward the inner circumferential surface of the housing 70.

Further, five springs or rings are attached to each end surface of the rotor 69 through the details, and the vanes 68
Alternatively, each bottom portion 68b of the bottom portion 68b may be pressed.

Furthermore, as shown in FIG. 1.3, the axial sliding portion 106 where the rotor 69 and the interposer 70d come into sliding contact and the axial sliding portion 106 where the rotor 69 and the interposer 70e come into sliding contact are provided with: Annular hydraulic chambers 109, 109 are formed, and these hydraulic chambers 109, 109 communicate with the hole 69b of the rotor 69 and with the oil passages 89, 90.

That is, the hydraulic chambers 109, 109 are connected to each suction and discharge lower
2, 74.76, communicates with the first oil passage OL through a flow passage 121 with a check valve 123 to receive high oil pressure, and a second oil passage connected to each suction and discharge lower 3° 75.77. It communicates with the OL 2 via a flow path 120 with a check valve 122 to receive high oil pressure.

Further, the flow path 120 with the check valve 122 and the flow path 121 with the check valve 123 may not be provided.

In addition, the reference numeral 69c in the figure indicates the inner diameter side bottom part of the rotor 69, 9
Reference numeral 1.92 indicates a bearing that pivotally supports the front export force shaft 5, and reference numeral 101 indicates a bolt.

Due to the hydraulic circuit 71, if a rotational speed difference occurs between the differential case 8 side and the rear export force shaft 4gA and the rotor 69 rotates relatively in the direction of arrow a, oil flows from the oil tank 80 to the check valve 79. After that, it is sucked into the suction ILt output lower 3, 75.77 through the m2 oil MOL, and then from the suction and discharge lower 2, 74.76 of the pump chambers 86 to 88 to the first oil passage OL, and then to the check valve 8 with an orifice 82a.
2 and is discharged to the oil tank 80. The discharge pressure characteristics at this time are shown by symbol A in FIG.

Conversely, when the rotor 69 rotates in the direction indicated by the arrow, oil is drawn from the oil tank 80 through the check valve 78 and into the suction/discharge lower 2.74° 76 through the first oil passage OL, and then into the pump chamber 86. ~88 suction discharge lower 3,75
, 77 and the second oil passage OL, and is discharged into the oil tank 80 through the check valve 81 with the orifice 81a. The discharge pressure characteristics at this time are shown by the symbols in FIG. 8.

In addition, in characteristic A, when the rotational speed difference exceeds a certain value, the discharge pressure hardly increases because the relief pulp 83 and 84 are in the range when the discharge pressure is above each predetermined value.

Furthermore, the characteristic portion before the relief valves 83 and 84 open in each characteristic A is proportional to the square of the rotational speed difference due to the action of the orifices 81a and 82a.

Uniformly, the leap characteristics of the relief valves 83 and 84 and the degree of constriction of the orifices 81a and 82a may be varied as appropriate.

Note that a part of the oil passage 104 is bored inside the rear export force shaft 4, and an oil filter is provided in the part of the oil passage 104 near the oil suction port, and oil is supplied through the oil supply passage. Iron powder and the like in the oil are prevented from entering the oil pump 14 by the magnet of the magnet attachment part and the oil filter.

Suction and discharge port of oil pump 14? 2, 74, the first oil passage OL connected to 76, and the suction and discharge port of the oil pump 14? A communication oil passage 207.208 is provided between the second oil passage OL connected to the oil passage 20? , 208 are provided with an orifice pulp 214 as a flow rate control mechanism M1.

The orifice pulp 214 is located on the right land 214a.
The position of the spool 214C is determined by the control hydraulic pressure and the pressing force of the left spring 214b, and the size of the orifice of the orifice valve 214 is determined. The flow rate of hydraulic oil passing through is determined.

The control oil pressure supplied to the land 214a of the orifice valve 214 can be controlled by a duty solenoid valve 213 that can return the oil pressure in the oil passage 206 and release it to the oil reservoir 80 through the oil passage 209. The valve 213 connects the automatic flow rate limit setting means M3 to the switching mechanism M and the operating state calculating means M.
The control unit 7) is controlled by receiving a control signal from a control unit 7) 128, which also serves as a manual control device (selector switch) 2 as a manual limit flow rate setting means M2.
A control signal is supplied from 15.

This manual control device 215 is disposed near the driver's seat, and is used to control the 4WD drive coupling device 13 for four-wheel drive.
The rate can be controlled remotely.

The control oil pressure supplied to this oil passage 206 is a constant pressure, and the high discharge pressure of O to 120 atmospheres from the first oil passage OL and the second oil passage OL 2 is maintained at a constant pressure. 2
01, 202 and the switching valve 210, and from the switching valve 210 through the oil passage 203 to the pressure reducing valve 211.
The pressure is reduced to about 0 atmospheres, and the orifice 20 of the oil passage 204
It is sent to the regulator valve 212 through the regulator pulp 4a, and is reduced to a constant pressure (about 8 atmospheres) by the regulator pulp 212 depending on the pump rotation speed, and is sent to the oil path 206 through the oil path 205 with an orifice 205a.

Each sensor is connected to the control unit 128, and the rotation speed sensor 12 as the above-mentioned driving state sensor
6, 127 and a steering angle detector 130 as a driving state sensor, a gear position sensor (inhibitor switch) 1 as a driving state sensor for detecting a gear position.
32.7 Accelerator opening sensor (throttle opening sensor) 133 as a driving state sensor that detects the amount of depression of the accelerator pedal (or opening of the throttle valve). Brake condition sensor 134f as a driving condition sensor that detects the depressed state of the brake pebble or engine braking condition Oil temperature sensor 13 as a driving condition sensor that detects lubricating oil etc.
In addition to rotation speed sensors 126 and 127, an engine rotation speed sensor 136 as an operating state sensor is provided.
A vehicle speed sensor 137 may also be provided.

In addition, in FIG. 3, 81' indicates a modified example of the check valve for preventing air intrusion, 81'a indicates an orifice, and 81'a indicates an orifice.
9a and 90a are centrifugal separation passages, 89b and 90, respectively.
b indicates a discharge passage, and further, reference numeral 128e in the figure indicates a memory of the control unit 128,
138 is a changeover switch forming the changeover rock WM4; 140
Reference numeral 140a indicates an oil pump, 140a indicates an externally toothed inner gear connected to the side outer shaft 143 of the torque converter, and 140b indicates an internally toothed outer gear.

The drive coupling device for four-wheel drive as an embodiment of the present invention is as follows:
As mentioned above, since the rear wheels 52 and 53 slip while driving in four-wheel drive, the rear wheel output shaft 4
When the rotational speed of the front export force shaft 5gA becomes faster than the rotational speed of the front export force shaft 5gA, the rotor 69 relatively rotates in the direction of the arrow a.

As a result, oil flows from the oil tank 80 through the check valve 79 and through the 12 oil passages OL2 to the suction and discharge lowers 3 and 7.
5.77, and is discharged from the suction/discharge lower 2, 74.76 of the pump chambers 86 to 88, through the first oil path OL, and from the check valve 82 with the oriice 82a to the oil tank 80.

This discharge pressure is a value that corresponds to the rotational speed difference between the rear wheel output shaft 4 side and the front output power shaft 5 side, so if the orifice valve 214 of the flow control fitNMl is fully closed, the oil pump 14 The magnitude of the transmitted torque also changes depending on the above-mentioned rotational speed difference [tight characteristics in Figure 8 (
orifice diameter)].

When a rotational speed difference occurs in this way, the four-wheel drive drive coupling device 13 comes into contact with a degree of coupling corresponding to this difference, so the rotational speed difference is suppressed, and as a result, the front wheels Torque is also transmitted to the output shaft 5 side. Thereby, even if the rear wheels 52, 53 are idling, the front wheels 43, 44 can be rotationally driven.

At this time, since the amount of torque transmitted by the four-wheel drive drive coupling device 13 is automatically controlled according to the rotational speed difference,
It does not cause deterioration of driving feeling or longitudinal stability.

Furthermore, if the rotational speed difference exceeds a certain value, for safety reasons,
Due to the action of the relief valve 84, an increase in the discharge pressure is suppressed to a constant value, and the torque transmitted between the shafts 4 and 5 does not exceed a constant value.

Conversely, if the front wheels 43, 44 slip, the rotor 69 automatically rotates relatively in the direction indicated by the arrow.

As a result, the oil supply path is automatically switched, and the oil flows from the oil tank 80 through the check valve 78.
It is sucked into the suction and discharge lower 2°74.76 through the first oil passage OL, and the suction and discharge ports of the pump chambers 86 to 88? 3,75.
77, the second oil passage OL2 is discharged from the check valve 81 with the orifice 81a to the oil tank 80. Since this discharge pressure also has a value corresponding to the rotational speed difference between the rear wheel output shaft 4 side and the front wheel output shaft 5 side, the magnitude of the torque transmitted by the oil pump 14 also changes according to the rotational speed difference.

In this case as well, the four-wheel drive drive coupling device 13 is brought into contact with the coupling degree according to the rotational speed difference, so the rotational speed difference is suppressed, and as a result, the rotational speed difference is suppressed, and as a result, the rear wheel output shaft 4 side Torque is also transmitted. As a result, even if the front wheels 43 and 44 are idling, the rear wheels 52 and 53 can be driven to rotate.

And, in this case as well, the four-wheel drive drive coupling system is adjusted according to the above-mentioned rotational speed difference! ! Since the amount of torque transmitted by 13 is automatically controlled, there is no possibility of deterioration of driving feeling or rolling stability.

In addition, in this case as well, if the above rotational speed difference exceeds a certain value,
For safety, the increase in discharge pressure is suppressed by the action of the relief valve 83 and becomes a constant value, so that the torque transmitted between the two shafts 4.5 does not exceed a constant value.

Furthermore, in this device, the product of the transmitted torque and the rotational speed difference results in energy loss and generates heat, but a portion of the oil is discharged to the oil tank 80 through the communication passages 89 and 90. Another advantage is that the hydraulic oil of the oil pump 14 can be sufficiently cooled and lubricated.

Furthermore, the orifice valve 214 of the flow rate control fi*M
To explain the opening/closing state of
2WD=4WD Lot4WD, 4WD-Hi) switching signal 1 that switches over the range (2WD=4WD Lot4WD, 4WD-Hi), and automatic limit flow rate revision means M
, a control signal from the control unit 128 as [each operating state detection sensor 126, 127, 130, 13]
2 to 137, the control signal 1 generated in the control unit 128 is received by the changeover switch 138 of the changeover mechanism M, and the manual control device serves as a manual flow rate limit setting means M2. According to the on/off signal from 215, when on, a control signal from the manual flow rate limit setting means M2 is sent to the duty solenoid valve 213 constituting the flow control If structure M1, and when off, the automatic flow rate limit setting means M2 is sent to the duty solenoid valve 213 constituting the flow control If structure M1 , the control signal from duty solenoid valve 2
Sent to 13.

As a result, the flow rate of the hydraulic oil passing through the communication oil passages 207 and 208 is controlled by the orifice pulp 214 that constitutes the flow rate control mechanism M1.

Hereinafter, as shown in FIGS. 5(a) to 5(d), detailed description will be made according to flowcharts.

The control unit 128 reads the reference slip ratio 00, etc. from the memory 128e (step al), and then reads the engine speed signal Ne from the speed sensor 127 (or the engine speed sensor 136) and the steering wheel. Steering angle signal f from angle detector 130, gear position signal Spw from gear position sensor 132
Accelerator opening signal θa from 7-gasle leap sensor 133
, brake state signal B from the brake state sensor 134
e and the oil temperature signal T from the oil temperature sensor 135 is received (step a2).

And brake-like! ! ! ! If (brake is on), it is in a deceleration state, so a control signal is sent from the control unit 128 to the flow rate control mechanism M1 to reduce (restrict) the on/off diameter of the orifice valve 214 (step a11).

That is, when the rear wheels 52 and 53 tend to lock up during braking, the rotational speed difference between the first rotating shaft 5 and the second rotating shaft 4 connected to the four-wheel drive coupling device main body 13 becomes very different.

As a result, in the vane pump 14, oil flows as shown by the solid line in FIG. 2, and a large hydraulic pressure is generated. However, when a predetermined value is exceeded, the relief valve 83 opens against the spring 83a and the discharge pressure is reduced to almost zero. Constantly controlled, rear wheel 52.5
3, a four-wheel drive state is established in which a constant driving force corresponding to a constant discharge pressure is transmitted.

Then, the rotational speed of the front wheels 43, 44 decreases, and the rotational speed of the rear wheels 52, 53 increases, reducing the rotational speed difference (same function as a non-slip differential).

In this way, when the front wheels 43 and 44 are in a slip state, the rear wheels 5
In addition, if the rear wheels 52 and 53 are slightly locked, the brake torque of the front wheels 43 and 44 is increased to prevent the rear wheels 52 and 53 from being unable to run due to increased drive torque. prevent locking.

When the brake is not activated, if the oil temperature T is larger than the set value To (step a4), it is assumed that the oil is in a heated state, and the orifice diameter of the orifice pulp 214 is increased (Ill
A control signal is sent from the control unit 128 to the flow rate control mechanism M (step a1
2).

As a result, when the hydraulic oil is at a high temperature, the discharge pressure is relieved and the four-wheel drive state is not achieved, but the torque transmitted to the rear wheel drive system is reduced and the system becomes a front-wheel drive state. As a result, the rise in prices will be suppressed.

That is, in the case of a differential pump such as the vane pump 14, a relief valve for controlling the discharge pressure (the reference numeral 83 in FIG.
．． Before the relief valve is opened, the discharged oil leaks from the sliding part clearance, and after the relief valve is opened, it all leaks from the sliding part clearance and the relief hole. At this time, heat is generated, and the amount of heat generated is proportional to the product of the discharge pressure P and the discharge iQ.

This product (PXQ) is proportional to the product of the pump generated torque TP and the rotational speed difference ΔN.If there is a relationship between the pump generated torque TP and the rotational speed difference ΔN as shown in FIG. The amount of heat generated increases as the rotational speed difference ΔN increases.

Therefore, in this embodiment, when the rotational speed difference ΔN between the front and rear wheels continues to be large, the oil temperature does not rise above 200°C and the viscosity of the hydraulic oil decreases, causing the vane pump 14 to The sliding parts may seize or the vane pump 1
It is possible to solve the problem that the rubber parts such as the sealing material in the pump 4 are deformed and damaged and the function as a pump is impaired.

Furthermore, problems such as a decrease in the torque transmitted to the wheels that change between the driving state and the driven state due to a decrease in the discharge pressure, which may cause the four-wheel drive function to be lost, can also be solved.

Note that step ai1. After the operation a12 is completed, the process returns.

In addition, the actual slip rate is determined based on the following formula from the rear wheel rotation speed Rr converted from the rotation speed signal from the rotation speed sensor 126 and the front wheel rotation speed Rf converted from the rotation speed signal from the rotation speed sensor 127. Calculate C2 (step a5)
.

C1=(Rf-R')/Rr... (1) According to this slip rate CI, LE of the above-mentioned display device 129
Display may be made in D129a to D129d.

In addition, during steady driving (40 to 60 km/hour) with small fluctuations in the front and rear wheel rotational speeds Rf and Rr, if there is an unusual rotational speed difference between the front wheels 43°44 and the rear wheels 52.53, the warning light 131 will be activated. Lights up or flashes to give a warning to stop.

Furthermore, the steering angle (steering angle) f and the front wheel rotation speed R
f and the rear wheel rotation speed Rr, the warning light 131 is turned on or blinks if an abnormal driving condition occurs.

Next, if the manual control signal from the manifold + L full control 1M215 is ON (step a6), the manual 4WD (four-wheel drive) routine is processed, and in other cases, the engine torque T
E is calculated (step a7), and tire drive torque Tt is calculated using the following equation (step a7).
8).

T t = T [X (total reduction ratio)...(
2) Next, this tire drive torque Tt is less than or equal to a predetermined value (as small a value as possible) Tto (step a9), and
If the steering angle f is almost zero (or lfl<C1) (
In step a10), the process moves to a reference slip ratio update routine.

When the tire drive torque Tt is larger than the predetermined value Tto,
Further, if the steering angle f is not substantially zero (1r1≧ε1), the process moves to an automatic 4WD (four-wheel drive) routine.

In the reference slip ratio update routine, as shown in FIG. 5(b), the difference C0 between the reference slip ratio C6 and the actual slip ratio C1 is calculated based on the following equation (step b1).

C,=C,-C,...(3) Then, if this difference slip rate C1 is not zero (or IC11≧ε2, step b2), the actual slip rate C1 is set as the reference slip rate C8. A new setting is made (step b4).

If the slip ratio C1 is almost zero (or lc:l
+<C2), the value of the reference slip ratio C0 is held (step b3).

In this way, if the tire radii of the front wheels 43.44 and the rear wheels 52.53 are exactly the same, no differential rotation will occur when the vehicle is traveling straight, but the tires will wear out (generally, the front wheels 43.44 will wear out faster). ), tire rotation, etc., a differential rotation occurs between the front wheels 43.44 and the rear wheels 52.53 even when the vehicle is traveling straight.

Therefore, the slip ratio of the front and rear wheels when driving straight is always detected and stored as the reference slip ratio Cα (this is because the difference in tire radius between the front and rear wheels changes due to tire rotation, etc.). Even in this case, the reference slip ratio C6 can be re-memorized by detecting the slip ratio in the subsequent straight-ahead state.

In the automatic 4WD routine, as shown in Fig. 5(c),
A theoretical slip ratio Cα corresponding to the steering angle f is calculated based on the following equation (step c1, see FIG. 9).

Cc1=Co+Q −f ” ” (
4) Here, α is the steering angle f, as shown in Figure tIIJ9.
The ratio of the slip ratio C3 to the slip ratio C3 is shown.

Then, the difference C2 between the theoretical slip ratio Ca and the actual slip/two slip ratio CI is calculated based on the following formula (step c2
).

c2=c, -ca...(5) Comparing the theoretical slip rate Cα corresponding to this steering angle f and the actual slip rate CI, the front wheels are 43.44% higher than the rear wheels 52.44%.
53 (C+≧O), and the actual slip ratio CI that occurs when the front wheels 43.44 are idling during driving is greater than or equal to the theoretical slip ratio C3 (C2≧
0) (step c3), the front wheel 43.44 rotates slower than the rear wheel 52.53 (C, < 0),
In addition, the actual slip ratio C at which the front wheels tend to lock due to engine braking or Watt brakes is 43.44.
1 is smaller than the theoretical slip rate Cα (C,<O,
In step c4), a control signal is sent from the control unit 128 to the flow rate control mechanism M1 to reduce (narrow down) the orifice diameter of the orifice valve 214 (
Step c5).

As a result, the four-wheel drive rate (4WD
rate) can be increased.

When the slip ratios C, , C2, and Ca are in other states, the control unit 128 causes the orifice diameter of the orifice pulp 214 to be widened (opened).
A control signal is sent from the flow rate control mechanism M+ to the flow rate control mechanism M+ (step e6).

In this way, the actual slip ratio C3 is controlled to become the theoretical slip ratio Cα.

In the manual 4WD routine, as shown in FIG. 5(d),
A theoretical slip ratio Cα corresponding to the steering angle f is calculated based on the following equation (step di).

C,=C,+α−f ---(6) Then, the difference C2 between the theoretical slip ratio C3 and the actual slip ratio CI is calculated based on the following equation (step d2).

C2=C, -C...(A) Also, manual control 1lEft! 215+Thus, even when driving with the selected Oriais diameter, the front wheel 4
3.44 rotates faster than the rear wheel 52.53 (C+≧
0), and the actual slip rate C1 is the theoretical slip rate C
If it is extremely larger than α (C2≧C2′, where C2′ is the set value of the slip ratio) (step d3), the front wheels 43.44 rotate more slowly than the rear wheels 52.53 ( C,<O), and the actual slip ratio C1 is extremely smaller than the theoretical slip ratio Cα (C2≦−〇2′,
In step d4), a control signal is sent from the control unit 128 to the flow rate control mechanism M1 to reduce the orifice diameter of the orifice valve 214 (step d5).

Thereby, the four-wheel drive rate (4WD rate) can be increased.

When the slip ratios C,, C2, and Cα are in other states, the four stages (2WD, 4WD-Lo, 4WD) selected by the manual control device fi215.

A control signal is sent from the control unit 128 to the flow rate control mechanism M1 so that the orifice diameter becomes 4WD-Hi (step d6).

In this way, manual 4WD routines can
Compared to the routine case, the tolerance of the actual slip ratio C1 with respect to the theoretical slip ratio Ca can be made larger, and the characteristics of the manual can be fully exhibited.

In addition, when the vehicle is in a normal straight-ahead state, the front wheels are 43° and 44°
Since the effective radii of the tires and the rear wheels 52, 53 are the same and the slip rotational speed of the tires is small, the first rotating shaft 5 and the second rotating shaft 4 connected to the four-wheel drive coupling device 13
There is no difference in rotational speed between the two.

Therefore, no oil pressure is generated in the vane pump 14,
The driving force is not transmitted to the rear wheels 52.53, and the front wheels 43.44
Front-wheel drive only.

In this state, the front wheels 43, 44 and the rear wheels 52°53
Since the rotational speed difference between the rotation speed and the rotation speed is small and becomes 0 to 20 (rpm), the LED 129a lights up and "2WDJ" is displayed.

However, when the front wheels 43, 44 normally slip within about 2% even if there is no large slip, such as when the vehicle accelerates straight ahead, the rotational speed difference due to this is caused by the difference in the rotational speed of the first rotating shaft 5.
and the rotating shaft 4 of ttS2, the vane pump 14 functions to generate oil pressure according to this rotational speed difference,
The rotor 69 and the cam ring part 70a rotate together, and a driving force corresponding to this oil pressure and the pressure receiving area of the vane 68 is transmitted to the rear wheels 52 and 53, resulting in a four-wheel drive state.

In this state, the front wheels 43, 44 and the rear wheels 52°53
Depending on the rotational speed difference between the
d lights up, indicating to the driver the intermediate state or 4WD state from 2WD to 4WD.

Further, the control signal from the control unit 128 is
The duty rate of the duty solenoid valve 213 is automatically determined according to the driving conditions, and when the orifice of the orifice valve 214 is activated,
In addition to the above, there are cases where the accelerator is depressed in automatic 4WD.

That is, the accelerator opening degree θa, the engine speed Ne(r
pm), the gear position Sp is detected, and as the torque input to the tires increases, the orifice of the orifice valve 214 is narrowed to increase the 4WD rate and accelerate with the four wheels.

In addition to the above-mentioned cases, the orifice of the orifice pulp 214 may be opened in the following cases.

(1) In automatic 4WD and manual 4WD, if the oil temperature T is below a certain value T0'(<T.), the viscosity of the oil is high, so the orifice is opened to prevent the braking phenomenon caused by the oil pump 14. To avoid.

(2) In manual 4WD, even when driving in 4WD,
When cornering (especially when the steering angle f is large), 4WD
Reduce the rate to prevent braking phenomena.

Moreover, the duty rate in the duty remade valve 213 can be controlled as follows, and the communication oil passage 20? , 208, the orifice valve 214 is interposed in the orifice valve 214
As the orifice diameter increases, the communication oil passages 207, 20
Since the amount of oil flowing through the vehicle 8 increases, when a sharp turn is made, the discharge pressure can be lowered, as shown in FIG. 7, and the 4WD rate can be lowered.

Furthermore, as shown in the N116 diagram, the front wheel is 43.44 and the rear f#! The orifice diameter of the orifice valve 214 can also be changed depending on the rotational speed difference ΔN between 52 and 53 and the 11t speed. In this case, the orifice diameter can be made smaller during high-speed running. , four-wheel drive improves straight-line stability.

In this way, when turning at high speed, the turning radius is also large, so
Braking phenomena are minimal, and four-wheel drive ensures stable handling.

According to the embodiments of the present invention, the following effects or advantages can be obtained.

(1) Since the difference in rotational speed between the front wheels and the rear wheels can be displayed on a display device installed in the driver's seat or the like, the driver can be made aware of the driving status from moment to moment.

(2) By comparing the display obtained in advance according to the driving state of the mounted non-directly coupled (hydraulic pump type) coupling mechanism according to the above item 1 with the display in the current driving state of the vehicle, The driver can know that the vehicle is in four-wheel drive mode.

(3) According to item 2 above, it is possible to confirm that 4-wheel drive is activated during acceleration/deceleration, high-speed driving, low-friction roads, rough roads, etc. Stability, longitudinal stability, ability to drive on rough roads, etc.).

(4) During steady driving on a dry road, it is possible to detect a large rotational speed difference between the front and rear wheels. For example, it is possible to detect a discrepancy in the tire radius of the front and rear wheels. It is possible to determine whether the attachment is defective.

(5) According to the above item 4, it is possible to prevent the occurrence of power circulation in the WA drive system, and it is possible to prevent deterioration of fuel efficiency and damage to the drive system.

In addition, as a means for determining the priority between the manual flow rate limit setting means M2 and the automatic flow rate limit setting means M, manual priority setting means that always gives priority to one or the other or manual flow rate limit setting in an emergency is used. It is possible to use an emergency automatic 4WD priority setting means that prioritizes the control of the automatic limit flow rate setting means M over the control of the means M2.

Also, an oil reservoir 80 is provided as a communication oil passage that communicates the discharge side and the suction side of the suction and discharge lowers 2 to 77, and serves as an oil reservoir from the discharge side to the atmosphere side in the transmission case 94.
A communicating oil passage may be formed to supply hydraulic oil from the oil passage 104 to the suction side via the first oil passage OL, as shown by the two-dot chain line in FIG. (or second
A communicating oil passage 207' is provided to communicate the oil passage OL2) or oil passage 203 with the oil reservoir 80, and this communication oil passage 20
7', an orifice valve 21 as a flow rate control mechanism M;
4 may be inserted.

Then, the effects of the above-mentioned embodiments can be obtained.

Furthermore, the oil pump 14 is not limited to the vane pump, and other oil pumps can be incorporated and used in the same manner as in the above embodiments.

Note that the front export power shaft 5 of the four-wheel drive drive coupling device 13 may be connected to the output shaft of the automatic transmission Wi2.

Furthermore, it goes without saying that this embodiment can be applied to an automobile equipped with a manual transmission.

〔Effect of the invention〕

As described in detail above, according to the four-wheel drive drive coupling device of the present invention, η The hydraulic connection 8! is provided with a rotating shaft and a hydraulic coupling mechanism interposed between the first rotating shaft and the second rotating shaft to mutually transmit driving force. a communicating oil passage configured as a hydraulic pump type coupling mechanism and communicating an oil passage connected to a discharge port of the coupling mechanism and an oil passage connected to a suction port (including an oil reservoir) of the coupling mechanism; A flow rate control mechanism that can control the flow rate (from zero flow rate to non-restricted flow rate) of hydraulic oil passing through the communication oil passage is provided, and a control signal is output to the flow rate control mechanism to set the restricted flow rate. a manual flow rate limit setting means for setting the flow rate limit; a driving condition sensor for detecting the driving condition of the vehicle; and a control signal for receiving the detection signal from the driving condition sensor and outputting a control signal to the flow rate control mechanism for setting the flow rate limit. The flow rate control 8!1 selectively uses only a control signal from one of the manual flow rate limit setting means and the automatic limit flow rate setting means.
It has a simple structure that includes a switching mechanism for sending it to the
The following effects or benefits, α, can be obtained.

(1) Since differential rotation between the front and rear wheels is allowed, it is possible to solve problems such as tight corner braking of part-time four-wheel drive vehicles and the complexity of driving maneuvers.

(2) Force is transmitted between the first rotating shaft and the second rotating shaft from the one rotating faster to the one rotating slower, so
This prevents either the front or rear wheels from over-rotating, reliably preventing wheelspin, and contributing to vehicle stability.

(3) Compared to the center differential conventionally installed in full-time four-wheel drive vehicles, it can be made smaller and lighter, and can also contribute to lower costs.

(4) When making a sharp turn at low speed, the difference in rotational speed between the rotational shaft on the front wheel side and the rotational axis on the rear wheel side can be tolerated, and braking phenomena can be reliably prevented.

(5) Straight-line stability of the vehicle is ensured when driving at high speeds.

(6) Control of the amount of torque transmitted by the oil pump can be selectively switched to either manual control or automatic control according to the rotational speed difference between the first rotating shaft and the second rotating shaft. , it is possible to fully demonstrate its functions without causing deterioration in driving feeling or steering stability.

[Brief explanation of the drawing]

Figures 1 to 9 show a four-wheel drive drive coupling device as an embodiment of the present invention; Figure 1 is a hydraulic system diagram showing its hydraulic pump type coupling mechanism and hydraulic circuit; A schematic configuration diagram showing the power system of a vehicle equipped with the device, Figure 3 is a sectional view of its main parts, Figure I:1IJ4 is its block diagram, Ml
, 5(a) to 5(d) are graphs for explaining the effect, and FIGS. 6 to 9 are graphs for explaining the effect. 1...Engine, 1a...torque converter, 2...automatic transmission, 3, 3'...gear, 4...rear export power shaft as second rotating shaft, 5...as first rotating shaft Front export power shaft, 8...Differential case, 9゜10...Pinion, 11
．． 12...Side gear, 13...4-wheel drive drive coupling device, 14...Oil pump (vane pump), 38.3
8'...Gear, 38a...Output shaft, 39...Ring gear, 39'...Gear, 40...Front wheel differential, 41.4
2.. Front wheel shaft, 43. 44.. Front wheel, 45.. Bevel gear mechanism, 45a, 46a.. Gear, 47.. Propeller shaft, 47a.. Bevel gear, 48.. Ring gear, 49.
- Rear wheel differential, 50.51... Rear wheel axle, 52°53...
Rear wheel, 64a... Spline engagement part, 68... Vane,
68a... tip, 68b... bottom, 69... rotor,
69a...outer circumferential surface, 69b...hole, 69c...bottom on inner diameter side, 70...housing, 70a...cam ring part,
70b...cover, 7Qc...7 lunge, 70d, 70
e...Intermediate material, 71...Hydraulic circuit as discharge pressure control mechanism, 72-77...Suction/discharge port, 78.79/◆Check valve, 80...Oil reservoir (oil tank), 81.81
', 82...Check valve for preventing air intrusion, 81a, 81
'a, 82a... Orifice, 83, 84... Relief valve for discharge pressure control, 83a, 84a... Spring, 8
6-88...Pump chamber, 89.90...Communication path, 89a
. 90a...Centrifugal separation passage, 89b, 90b...Discharge passage, 91-93...Bearing, 94...Transmission sink case, 95.96...Bushing (bearing),
101... Bolt, 104... Oil passage, 106... Axial sliding part, 109... Oil chamber, 120° 121... Channel, 1
22,123...check valve, 126...rotation speed sensor (pickup) as second rotation speed detector (operating state sensor), -i 27...as first rotation speed detector (operating state sensor) rotation speed sensor (pickup),
128...control unit, 128a, 128b
Counter, 128c Timer, 128d Arithmetic unit (CPU), 128e Memory, 129 φ display device, 129a to 129d LED, 130 Steering angle detector as driving state sensor ( steering angle sensor), 131... warning light, 132... gear position sensor (inhibitor switch) as driving state sensor, 133...
- Accelerator opening sensor (throttle opening sensor) as a driving state sensor, 134... Brake state sensor as a driving state fi-t sensor, 135... Oil temperature sensor as a driving state sensor, 136... Operating state Engine speed sensor as a sensor, 137... Vehicle speed sensor as a driving state sensor, 138... Changeover switch, 140...
・Oil pump, 140a... External tooth inner gear, 14
0b...Inner gear outer gear (casing), 142...Input shaft (inner l), 143...Pump side outer shaft of torque converter, 201-206...Oil path, 204a, 205a...
・Orifice, 207.207', 208...Communication oil passage, 209...Return oil passage, 210...Switching valve, 211...
・Reduced pressure pulp, 212...Regulator pulp, 213
...Duty solenoid pulp, 214...Orifice pulp, 214a...Land, 214b...Spring, 214c...Spool, 2151+6 manual control 1ifi, M. ...Flow rate control mechanism, M2...Manual limit flow rate setting means,
M... automatic limit flow setting means, M4... switching mechanism,
Ms...operating state calculation means, OL,...first oil path, OL
2. Second oil road.

Claims (1)

[Claims] A first rotating shaft that transmits driving force to the front wheels of the vehicle, a second rotating shaft that transmits driving force to the rear wheels, and an interposed device between the first rotating shaft and the second rotating wheel. and a hydraulic coupling mechanism capable of mutually transmitting driving force, and the hydraulic coupling mechanism is configured as a hydraulic pump type coupling mechanism, and the oil passage connected to the discharge port of the coupling mechanism and the hydraulic coupling mechanism are provided. A communication oil passage that communicates with the oil passage connected to the suction port and a flow rate control mechanism capable of controlling the flow rate of hydraulic oil passing through the communication oil passage are provided, and a flow rate limit is set for the flow rate control mechanism. a manual flow rate limit setting means for outputting a control signal to control the vehicle; a driving condition sensor for detecting the driving condition of the vehicle; and a driving condition sensor that receives a detection signal from the driving condition sensor and sets the flow rate limit to the flow rate control mechanism. an automatic limit flow rate setting means that outputs a control signal for controlling the flow rate; and selectively sending only a control signal from one of the manual limit flow setting means and the automatic limit flow setting means to the flow control mechanism. A four-wheel drive drive coupling device, characterized in that it is provided with a switching mechanism.