JPH06107020A - Hydraulic control system for vehicles with automatic transmission - Google Patents

Abstract

(57) [Abstract] [Purpose] In a vehicle control device of a type in which a hydraulic device for an automatic transmission and a power distributor are connected, and control oil is supplied from a common hydraulic pressure source to the hydraulic control device, The controllability of the hydraulic control device for the automatic transmission is ensured without increasing the capacity and increasing the number of sources. [Configuration] The hydraulic control device 40 (first hydraulic control device) of the automatic transmission 1 and the power distributor 2 A hydraulic control device for a vehicle, which hydraulically connects to the hydraulic control device 100 (second hydraulic control device) and has a common hydraulic pressure generation source 30,
When the determination unit 5 (power distribution electronic control unit) detects that the required control oil flow rate on the hydraulic control unit side increases, even if the second hydraulic control unit requires control oil, the (2) A flow rate limiting unit that limits the flow rate of control oil supplied to the hydraulic control device side is provided to suppress deterioration of controllability on the automatic transmission side.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle hydraulic control device, and more particularly to a hydraulic control device in which a hydraulic control device for an automatic transmission and a hydraulic control device for a power distributor are hydraulically connected.

[0002]

2. Description of the Related Art Generally, an automatic transmission for a vehicle is controlled by supplying / discharging hydraulic pressure to / from a hydraulic actuator of each friction engagement means in the automatic transmission according to the vehicle state. In addition, in recent years, a friction distributor is provided in a power distributor that distributes the driving force from the engine to the front and rear or the left and right, and front and rear or left and right differential rotation is performed by controlling the supply and discharge of control oil to and from the friction distributor. A power distributor that arbitrarily controls the switching of power and the like has also been proposed. Among them, in order to standardize the device or parts in the vehicle that controls the power distributor and the vehicle that does not control the power distributor, the hydraulic controller of the power distributor is connected to the hydraulic controller of the automatic transmission to provide a common hydraulic source. A technique for sharing the same is described in, for example, Japanese Patent Application Laid-Open No. 61-44031.

This publication describes an automatic transmission (hereinafter A / T).
Hydraulic control device and four-wheel drive transfer (hereinafter T /
It is disclosed that the hydraulic control device of F) is connected and the line pressure adjusted by the hydraulic control device of A / T is used as the source pressure of the control oil of T / F. This control oil is used to control the two-wheel / four-wheel switching clutch provided in the T / F and the clutch and brake of the auxiliary transmission.

[0004]

In the above device, the A / T hydraulic control device and the T / F hydraulic control device can be independently controlled. Therefore, for example, when the control oil pressure is being supplied to the T / F oil pressure control device, if the control oil also needs to be supplied to the A / T oil pressure control device, the flow rate temporarily becomes insufficient, and the A / T oil pressure control device There arises a problem that controllability deteriorates. In particular, when performing garage parking, parallel parking, etc., the shift lever is switched from neutral (N) to the forward range or reverse range while supplying control oil to the T / F hydraulic control device in order to maintain the T / F in a certain state. When the switching is performed, there arises a problem that the flow rate of control oil supplied to the A / T hydraulic pressure control device is insufficient, the shift time is extended, and the operation feeling is significantly deteriorated.

The present invention has been made in view of the above circumstances and is provided with an automatic transmission that connects an A / T hydraulic control device and a T / F hydraulic control device and uses a common hydraulic pressure generation source. It is an object of the present invention to provide a hydraulic control device for a vehicle, which has excellent controllability without increasing the capacity or increasing the hydraulic pressure generation source.

[0006]

In order to achieve the above object, the present invention provides a first hydraulic control device for controlling the shift of an automatic transmission, and a power distribution for distributing the output from the automatic transmission to each wheel. And a second hydraulic control device for controlling the power distributor, the first and second hydraulic control devices being hydraulically connected to each other and having a common hydraulic pressure generation source, and the first hydraulic control device.
And a hydraulic control device for a vehicle with an automatic transmission in which the second hydraulic control device can control each independently, and a determining means for detecting or predicting an increase in the required flow rate of the control oil used in the first hydraulic control device. When the determination means determines that the required flow rate of the first hydraulic control device increases, even when the control oil is required or is being supplied to the second hydraulic control device, the second hydraulic control device is supplied with the control oil for a predetermined time. And a flow rate limiting means for limiting the supply of control oil.

[0007]

With the above-described structure, the present invention enables independent control of the hydraulic control device (first hydraulic control device) of the automatic transmission and the hydraulic control device (second hydraulic control device) of the power distributor in a steady state. When it is determined that the control oil flow rate used for the first hydraulic control device increases, the supply of control oil to the second hydraulic control device is limited for a predetermined time, so that the control oil required for the first hydraulic control device is limited. The flow rate can be secured.

[0008]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a schematic diagram showing the outline of the embodiment. FIG. 2 shows the characteristic portion of FIG. 1 in more detail.

First, FIG. 1 will be described. Examples are
The present invention is applied to a four-wheel drive vehicle with an automatic transmission, and includes an engine 3, a hydraulic pressure generation source 30 that is constantly driven by the engine 3, an automatic transmission 1, and a friction-type multi-plate that constitutes the automatic transmission. A first hydraulic control device 40 is provided for controlling supply / discharge of control oil to / from a hydraulic actuator that is provided to be able to press a clutch or a brake, according to the vehicle state. Further, the second hydraulic control device 100 includes a power distributor 2 that distributes the power output from the automatic transmission to the front and rear wheels, and the second hydraulic control device 100 supplies control oil to a hydraulic actuator provided in the power distributor 2. It is a control device that controls the operation of the power distributor 2 by controlling the discharge.

In the twelfth embodiment, when the determining means 5 detects that the required flow rate of the first hydraulic control unit 40 is increased based on information from the electronic control unit (ECU) for the automatic transmission, the second hydraulic pressure is set. The inflow of the control oil to the second hydraulic control device is restricted by the flow rate restricting means provided in the control device 100. In this case, even if the control oil is supplied to the hydraulic actuator of the power distributor, or even if the supply of the control oil is about to be started, the control is temporarily prohibited and the hydraulic actuator of the power distributor is not controlled. It is configured to limit the supply of control oil.

FIG. 2 showing in detail the characteristic parts of the above-described embodiment, FIG. 3 showing the relationship between engagement and disengagement of each friction engagement element of the automatic transmission 1 and shift position, and the clutch of the power distributor 2. Further description will be given based on FIG. 4 showing the control flow.

The automatic transmission 1 shown in FIG. 2 is composed of three planetary gear units, three friction type multi-plate clutches, and four friction brakes. As shown in FIG. 3, the shift lever is parked. In the range (P) or the neutral range (N), all but the clutch C ₀ are in the released state. From that state, the forward range (eg D
Range: 1st gear when the vehicle is stopped or close to a stopped state) or reverse range (R) when shifting to 1 in the D range and 2 friction clutches or brakes in the R range From the state to the engaged state,
Since the first hydraulic control device engages the clutch or brake on the automatic transmission side, a large amount of control oil must be supplied to the hydraulic actuator of the clutch or brake. In this way, when the N or P range is switched to the forward stage (D) range or the R range, the control oil flow rate required by the first hydraulic control device increases. At this time, if the required flow rate is not ensured on the side of the first hydraulic control device, the shift time may be delayed and the operation feeling may be deteriorated.

On the other hand, the transfer in the embodiment is
The force distributor 2 is a set composed of a single planetary.
It has an inter-diff 15. 2 of the center differential 15
Two output members, sun gear 12 and ring gear 14.
Are the rear wheel side output shaft 10 and the rear wheel side output shaft 1, respectively.
Power is applied to the front wheel side output shaft (not shown) that is arranged in parallel with 0.
Is connected to the drive side sprocket 20 that transmits
Further, the sun gear 12 is a clutch C._TenInput member through
Can be connected to the carrier 16. like this
2 is a clutch C_TenIs open
The so-called center differential free four-wheel drive condition (this state
State 1), clutch C_TenCenter engaged with
Diff lock four-wheel drive state (this state is the second state),
Latch C _TenTo control the target power distribution state
Torque split four-wheel drive state (this state
State), a total of three four-wheel drive states are set according to the vehicle state.
It is possible.

Specifically, in the first state, the center differential distributes the driving force from the automatic transmission at a ratio of 3 to the front wheel side (sun gear 12) and 7 to the rear wheel side (ring gear 14), and in the second state. Since the carrier 16 which is an input member and the sun gear 12 are connected by the clutch C ₁₀ , the ring gear 14, the carrier 16, which constitute the center differential 15,
Since the three members of the sun gear 12 rotate integrally, a so-called differential lock (direct connection) state in which front and rear wheels are not allowed to be differential is formed, and the driving force is distributed to the front and rear wheels at a ratio of about 5: 5. [In addition, when the center differential is directly connected to the above,
The distribution ratio to the front and rear wheels varies depending on the road surface conditions of the front and rear wheels and the ground load of the front and rear wheels (which also changes depending on the acceleration / deceleration), and is therefore expressed here as approximately 5: 5]. In the third state, the driving force distribution to the front and rear wheels is variably controlled in the range of 3: 7 to approximately 5: 5 (direct connection) by controlling the engaging force of the clutch C ₁₀ .

In this embodiment, in order to further improve the stability of the vehicle, "center diff lock control at start" as known from Japanese Patent Laid-Open No. 55-72420 is performed. Therefore, the control mechanism is configured so that the control pressure is supplied to the clutch C ₁₀ through the second hydraulic control device side 100 at a substantially maximum value so that the clutch C ₁₀ is completely engaged, that is, in the second state at the time of starting. It is configured.

Next, the hydraulic control mechanism will be described. First, the control oil supplied from the oil pump 30 (hydraulic pressure generation source) is adjusted to a pressure suitable for the automatic transmission 1 side in accordance with the vehicle condition (for example, vehicle speed, gear stage, engine load such as throttle opening). The pressure is regulated by a pressure regulating valve (not shown) provided in the hydraulic control device 40. The regulated pressure is called line pressure (P _L ) and is constantly supplied to the oil passage 42. This oil passage 42 is also connected to the second hydraulic control device 100, and serves as the supply pressure to the clutch C ₁₀ described above.

The second hydraulic control system for controlling the clutch C ₁₀ comprises a pressure reducing valve 50, a solenoid proportional valve 60, and a control valve 70. Each of the valves shown in FIG. 2 shows different operating states on the left and right sides with respect to the central object.
In the control valve 70, the left side of the figure shows the first state and the right side of the figure shows the second state.

The oil passage 42 branches in the second hydraulic control unit,
One is connected to the port 51 of the pressure reducing valve 50, and the other is connected to the port 72 of the control valve 70. The pressure reducing valve 50 is provided with oil chambers arranged oppositely on both sides of the spool 53, and the oil chamber 57 on one side urges the spool upward in the drawing, that is, the pressure output from the port 52 increases. It has a spring 54 that acts so as to urge it to the pressed side, and the pressure output from the port 52 is supplied to the oil chamber 55 on the other side through the groove 56. On the contrary, when the output pressure from is increased, it acts to move the spool to the side where the pressure is reduced. By controlling the position of the spool 53 so that the forces of the two chambers facing each other are balanced as described above, the line pressure supplied from the port 51 is reduced and a substantially constant modulating pressure (P _MO ) is output from the port 52. Is configured.

The modulated pressure (P _MO ) is supplied to the port 63 of the solenoid proportional valve 60. The solenoid proportional valve 60 causes a thrust generated according to a current flowing through a solenoid 65 to act on a spool 64 via a plunger 66, and the current is supplied from a transfer electronic control device (determination means 5) according to a vehicle state. It is controlled by a control signal. By moving the spool 64 in the vertical direction, the hydraulic pressure (control pressure: P _SOL ) in the oil passage 62 communicated via the port 61 can be adjusted to an arbitrary pressure. The control pressure P _SOL is set to have a one-to-one correspondence with the clutch pressure (P _C ) that determines the engagement state of the clutch C ₁₀ .

The control valve 70 sandwiches the spool 74.
Oil chambers 73 and 75 are formed at both ends facing each other.
The control pressure (P_SOL) Is supplied to the oil chamber 7
3 has a spring 76 acting in the opposite direction to the control pressure.
And the pressure in the oil passage 72 is used as feedback.
Is supplied. Further, the control valve 75 has a drainage.
Ports 77, 78 and oil passages communicating with the room (open to the atmosphere)
42 and line pressure (P_L) Is supplied to port 7
2, clutch C for controlling the differential of the center differential 15_Tenof
An oil passage 72 communicating with a hydraulic actuator (not shown)
Clutch pressure (P_C) Output port 71
And each port is provided on the spool 74
It can be intermittently operated by three lands. For example,
The state on the left side of FIG. 2 is the control pressure (P_SOL) Gaho
Since it is the minimum value, the oil chamber 73 is biased upward in the figure.
Shows a state in which the force has exceeded and the spool 74 has moved upward.
And in that case, the line by the land 79 in the middle
Pressure (P_L) Supply is interrupted and the oil passage 72 is drained.
Communication with the import port 78. As a result, the clutch C _Tenof
Clutch pressure in hydraulic actuator (P_C) Is discharged
The fully opened state (that is, the first state) is set.

The solenoid proportional valve 60 and the control valve 70
Also constitutes a flow rate limiting means constituting the present invention,
It is possible to limit the supply flow rate to the clutch C ₁₀ side where there is control oil leakage. This flow rate limiting means may limit the control oil flow rate required for the first hydraulic pressure control device 40 on the automatic transmission side to the extent that the preset supply amount to the clutch C ₁₀ can be secured as much as possible, but in the present embodiment. For ease of control, the transfer electronic control device (determination means 5) is the first
When it is determined that the required flow rate of the hydraulic control device 40 increases, the control pressure (P _SOL ) output from the solenoid proportional valve 60
Is set to almost 0, and the control valve 70 is set to be switched to the above-mentioned state on the left side in FIG. Normally, even when the first state is set, a slight hydraulic pressure is generated in the control pressure of the oil passage 62 as a standby mechanism so that the second and third states can be immediately changed. A small amount of current is flowing in the solenoid proportional valve, and it is positioned slightly below the position of the spool 64 shown on the left side of FIG.

The control flow shown in FIG. 4 will be described based on the configuration described above. This control flow is a flow relating to a method of calculating the clutch pressure P _C supplied to the clutch C ₁₀ . This clutch pressure P _C and the clutch pressure P
_The control pressure P _SOL regulated by the solenoid proportional valve 60 to obtain _C and supplied to the control valve 70 is set in a one-to-one correspondence. Therefore, in actuality, after this control, the corresponding P _SOL pressure is obtained in order to obtain the set clutch pressure P _C , and a control for supplying a preset current to the solenoid proportional valve 60 to obtain that pressure is performed. Will be done. FIG. 5 shows how the clutch pressure P _C changes as a result of this control (control disclosed in FIG. 4).

The clutch C _{10 of the} transfer 2 is controlled so as to be in one of the first to third states according to the vehicle state, but in the present embodiment, the clutch C ₁₀ at the time of starting the vehicle.
By engaging in the second state, the aim is to limit the differential rotation between the front and rear wheels and improve the stability of the vehicle.
However, in the following control flow, even under the condition that the center differential differential limiting control at the time of starting is executed, the control is executed by the first hydraulic control device on the automatic transmission side. When the oil flow rate becomes insufficient and the shift feel is adversely affected, the inflow of the control oil to the transfer side is limited to open the clutch C ₁₀ .

First, step (hereinafter S) 1 shown in FIG.
In order to determine whether or not the vehicle is in the start state, the current vehicle speed (V) is substantially stopped at a speed lower than the predetermined vehicle speed (V ₀ ),
In addition, it is determined whether the neutral range (N) or the parking range (P) is switched to the forward gear (D range, 2nd range, etc.) or the reverse gear range (R).
If both conditions are satisfied here, it is determined that the vehicle is in a starting condition and S
Go to 2, otherwise return.

Incidentally, the present starting state refers to a starting state in particular when the above-mentioned condition is satisfied, that is, a starting state accompanied by the driver's shift operation, and the required flow rate of the control oil on the side of the first hydraulic control unit 40 increases. However, it is also a condition that the possibility of insufficient flow rate increases. Therefore, for example, the first hydraulic pressure control device 4 such as a starting state generated by releasing the brake from the stopped state due to the brake ON in the D range state
It is set except for the starting state in which the required flow rate on the 0 side does not increase.

S2 indicates that the clutch pressure P _C is controlled so as to become the clutch pressure P _CT at the present time. As shown in the time chart of FIG. 5, this clutch pressure P _C is controlled by the electronic control unit for transfer so as to be a predetermined clutch pressure in the control before S1.
The center differential 15 is in the third state with some restrictions. This time, the pressure is set so as to be in the restricted state in the state of S2, but in the vehicle state, the _PCT pressure in S2 may be the pressure in the first state. The control of the S2 is maintained for a predetermined time T _A by the step of S3 to S4. This predetermined time T _A is the control judgment (S
2) A time for forming a delay time from the start to the next step and preventing unnecessary switching of the clutch C ₁₀ . This predetermined time T _A may be set in the same manner as the delay time set for the electronic control unit on the automatic transmission 1 side to determine whether or not the shift switching of S1 is actually performed. Good.

When it is determined in S4 that the predetermined time T _A has elapsed, the process proceeds to S5, and it is determined in more detail whether or not the condition is such that the shift feel deteriorates due to insufficient flow rate on the automatic transmission side. Therefore, the brake is depressed, the shift range is other than the neutral range, and the throttle opening θ
Is less than the predetermined opening degree, it is determined that the shift delay is particularly likely to be transmitted to the driver as a deterioration of the feel, and S6 is executed. This control condition is considered to be that the vehicle is stopped when the brake is on, and it is expected that a smooth start of the vehicle is expected when the throttle opening is small. Is considered to be increased and transmitted to the driver,
In this control, S6 is set so that the flow rate limiting control is executed only in that case.

Also, this time, it is used as the source pressure of the control pressure.
Line pressure normally increases with engine load.
Since it is set to
Degree θ ₀The current throttle opening θ is the value θ₀Above
If so, the flow rate of control oil generated by the oil pump is
And the second hydraulic control device side 40, 100 are controlled simultaneously
You may set to the value which becomes a necessary and sufficient state. Well
If the determination condition of S5 is not satisfied, S9, which will be described later, is performed.
Set clutch pressure P_CTo P_CTControl to return to
To go.

In S6, the set pressure of the clutch pressure P _C is set to zero. In order to reduce the clutch pressure P _C to 0, as described in the description of the second hydraulic control device 100, the solenoid proportional valve 6
By cutting off the control current of 0 and making the control pressure P _SOL almost 0, the control valve 70 is switched to the state on the left side of FIG. As a result, the supply of the control oil from the hydraulic pressure 42 to the oil passage 72 is cut off, and the oil passage 72 is closed by the drain port 7.
8, the clutch pressure P _C of the oil passage 72 is almost 0.
Becomes For this reason, the control oil consumption due to leakage or the like between the hydraulic devices from the control valve to the clutch C ₁₀ is suitably reduced, and the control oil flow rate required by the first hydraulic control device of the line oil passage 412 is secured. .

In subsequent steps S7 and S8, the control for the predetermined time T _B is restricted from shifting to S9. This predetermined time T _B
Is preferably set to the time required for the automatic transmission to shift from the actual start to the completion of shifting, and the prestored time may be corrected depending on the engine load and the shift range. Good. Further, during the predetermined time T _B , S
If the determination condition of 5 is not satisfied, the process proceeds from S5 to S9.

In step S9, after the time T _{B has} elapsed, the set clutch pressure P _C is returned based on the disclosed formula so as to become the clutch pressure P _CT at the above-mentioned control start time. The coefficients K ₁ and K ₂ of the equation shown in S9 determine the transient characteristics when returning, and may be changed according to the conditions.

Although the embodiment has been described above with reference to FIGS. 1 to 5, the present invention is not limited to the above embodiment and can be carried out in another mode without departing from the scope of the present invention. is there.
For example, although the embodiment discloses an example in which the present invention is used in a transfer hydraulic control device for a four-wheel drive vehicle, the hydraulic pressure of a front differential or a rear differential that distributes power to the left and right wheels of an FF vehicle, an FR vehicle, or the like. You may use for a control apparatus.

Further, in this embodiment, the flow rate control means is arranged in the second hydraulic pressure control device, and the electromagnetic proportional valve 60 and the control valve 70 have the same function, which is shown by A and B in FIG. It is also possible to newly provide a flow rate limiting device in such a place.

Further, in the control flow S1 of FIG. 4, conditions for increasing the required flow rate are predicted in advance, and the flow rate increase is judged by the satisfaction of the conditions. Various sensors are provided to detect the actual flow rate of control oil. You may make that judgment.

The control for setting the clutch pressure P _C = 0 in S6 may be executed immediately after the condition of S1 is satisfied. However, in this case, it is preferable that the time for maintaining P _C = 0 is set to a time in which both the predetermined times T _A and T _B are taken into consideration. Of course, it is similarly possible to execute S9 after S4.

In addition to the differential limiting clutch of the embodiment,
For example, similar control can be performed even with a hydraulic control device such as an intermittent clutch for power transmission, a switching clutch or a brake of a sub transmission of a transfer device.

In the present embodiment, the condition for restricting the control oil flowing out to the second hydraulic control device side is set at the time of switching the shift range at the time of starting, but other conditions depending on the temperature may be used. For example, the required flow rate of the first hydraulic control device is insufficient due to an increase in the viscous resistance of oil at low temperature (before warming up),
It may be set in consideration of the shortage of the required flow rate due to the increase of the leak amount when the control oil temperature is high.

[0038]

According to the present invention, the automatic transmission hydraulic control device (first hydraulic control device) and the power distributor hydraulic control device (second hydraulic control device) are hydraulically connected to each other to provide a common hydraulic pressure. Even when the source is used, each hydraulic control can be executed independently in a steady state, and even during a transient time when the control oil flow rate required on the automatic transmission side increases,
The supply of control oil to the second hydraulic control device is limited only for a predetermined time, and the required flow rate of the first hydraulic control device is secured. Therefore, it is possible to secure the controllability on the automatic transmission side while suppressing the capacity increase of the hydraulic pressure generation source (compared to the type not provided with the second hydraulic pressure control device) or the expansion of the hydraulic pressure generation source as much as possible.

[Brief description of drawings]

FIG. 1 is a schematic diagram of an embodiment according to the present invention.

FIG. 2 is a diagram disclosing the points of the embodiment.

FIG. 3 is an engagement table of clutches and brakes in the automatic transmission disclosed in FIG.

FIG. 4 is a control flowchart of the embodiment.

FIG. 5 is a time chart showing the change over time in clutch pressure P _C.

[Explanation of symbols]

 1 Automatic Transmission 2 Driving Force Distribution Device (Transfer) 5 Judgment Means (Electronic Control Device for Transfer) 40 First Hydraulic Control Device 60 Electromagnetic Proportional Valve (Flow Rate Limiting Unit) 70 Control Valve (Flow Rate Limiting Unit) 100 Second Hydraulic Control apparatus

Claims (1)

[Claims] 1. A first hydraulic control device for controlling a shift of an automatic transmission, a power distributor for distributing an output from the automatic transmission to each wheel, and a second hydraulic control device for controlling the power distributor. A vehicle with an automatic transmission, in which the first and second hydraulic control devices are hydraulically connected to each other and have a common hydraulic pressure generation source, and the first and second hydraulic control devices are independently controllable. In this hydraulic control device, the determination means for detecting or predicting an increase in the required flow rate of the control oil used in the first hydraulic control device, and the determination means are the first
When it is determined that the required flow rate of the hydraulic control device will increase, the second
An automatic transmission including: a flow rate limiting unit that limits the supply of the control oil to the second hydraulic control device for a predetermined time even when the control oil is required or is being supplied to the hydraulic control device. Hydraulic control device for vehicles equipped with.