JPH04353027A - Hydraulic controller for power transmission device - Google Patents

Abstract

PURPOSE:To prevent the set hydraulic pressure of 4WD transfer-clutch from being deviated due to acceleration/deceleration. CONSTITUTION:Hydraulic pressure which is governed by a governor valve mechanism 2 is supplied to a friction engagement element 1. Since governing level is affected by acceleration/deceleration, acceleration/deceleration detected by an acceleration/deceleration detection means 3 is inputted in a compensation means 4, and the compensation means 4 compensates the governing level of the governor valve mechanism 2 based on acceleration/deceleration.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic control device for regulating hydraulic pressure supplied to frictional engagement elements in power transmission devices such as automatic transmissions and four-wheel drive devices for vehicles.

0002

2. Description of the Related Art Automatic transmissions for vehicles are configured to set a plurality of gears by appropriately engaging or disengaging frictional engagement elements such as clutches and brakes. It is widely known that four-wheel drive systems that can change the torque distribution ratio are configured to change the torque distribution ratio using a frictional engagement element that makes up the transfer or a frictional engagement element that limits the differential of the center differential. There is. The frictional engagement elements in these automatic transmissions and four-wheel drive systems are generally configured to be engaged by hydraulic pressure, and the higher the hydraulic pressure, the greater the transmission torque capacity, so the higher the engine load (i.e. output), the higher the hydraulic is set high to ensure the necessary transmission torque capacity. In addition, especially in four-wheel drive systems, in order to prevent tire slip when engine output is suddenly increased, the hydraulic pressure supplied to the frictional engagement elements is increased to ensure that the torque distribution ratio to the rear wheels is nearly even. It is controlled so that An example of this is described in JP-A-62-12422. In the invention described in this publication, a target distribution rate is determined based on the opening degree of the throttle valve and its rate of change over time. The engagement pressure of the clutch, which is the transfer mechanism, is controlled so that the

As a means for regulating the hydraulic pressure supplied to frictional engagement elements such as the above-mentioned clutch, for example, pilot pressure is applied to a spool that is pressed in one direction by a spring in the opposite direction to the spring, and the pilot pressure is adjusted. A pressure regulating valve configured to change the pressure regulating level (pressure regulating value) by changing the pressure is used. Recently, pilot pressure applied to the pressure regulating valve has also been generated by an electrically controllable valve such as a linear solenoid valve.

0004

[Problems to be Solved by the Invention] Valves for pressure regulation, such as the above-mentioned pressure regulation valves and linear solenoid valves, basically rely on the elastic force of the spring applied to the spool, the electromagnetic force generated by the solenoid, etc. Although line pressure is opposed to the load and the hydraulic pressure is adjusted according to the load, in the hydraulic control device installed in the vehicle, acceleration associated with driving acts on the spool, which increases the load. In order to increase or decrease the pressure, the pressure regulation level changes and there is a possibility that the desired oil pressure cannot be obtained. In particular, linear solenoid valves cannot make the solenoid part large due to constraints such as space and cost, so the electromagnetic force that can be generated is weak, and a spring with low elasticity is used to counteract this. Therefore, it is susceptible to external forces such as inertial force caused by acceleration, and there is a high possibility that the pressure regulation level will be out of order.

[0005] Changes in the pressure regulation level appear as deviations in the hydraulic pressure supplied to the frictional engagement elements from the target hydraulic pressure, so in automatic transmissions, it may cause worsening of shift shock or slippage of the frictional engagement elements. In addition, in the case of a four-wheel drive system, clutch slippage causes an error in the torque distribution ratio and changes in vehicle behavior as a result.

The present invention was made against the background of the above-mentioned circumstances, and it is an object of the present invention to prevent the hydraulic pressure supplied to the friction engagement element from deviating from the target hydraulic pressure due to the acceleration/deceleration.

[0007]

[Means for Solving the Problems] In order to achieve the above object, the present invention is constructed as shown in FIG. In a hydraulic control device for a power transmission device configured to regulate pressure by a pressure regulating valve mechanism 2 that regulates pressure according to load, an acceleration/deceleration rate that determines acceleration/deceleration acting on the valve body in a direction parallel to the acting direction of the load. The present invention is characterized in that it comprises a detection means 3 and a correction means 4 for correcting the load applied to the valve body according to the acceleration/deceleration determined by the acceleration/deceleration detection means 3.

[0008]

[Operation] Also in the hydraulic control system of the present invention, the hydraulic pressure supplied to the friction engagement element 1 is regulated by the pressure regulating valve mechanism 2. The pressure regulation level in this pressure regulation valve mechanism 2 is determined by the load applied to the valve body. On the other hand, the acceleration/deceleration acting on this pressure regulating valve mechanism 2 is detected by the acceleration/deceleration detection means 3.
The load applied to the valve body is corrected according to the determined acceleration/deceleration, so the pressure regulation level in the pressure regulating valve mechanism 2 is determined by the inertial force applied to the valve body based on the acceleration/deceleration. Even if the inertial force is applied, the inertial force can be offset by the corrected load, so that the hydraulic pressure supplied to the frictional engagement element becomes the desired pressure that is not affected by acceleration/deceleration.

[0009]

Embodiment FIG. 2 is a block diagram showing one embodiment of the present invention, and the example shown here is an example in which the present invention is applied to a hydraulic control device in a four-wheel drive device as a power transmission device. That is, in FIG. 2, the power output from the engine 10 via the transmission 11 is distributed and transmitted to the front wheel output shaft 13 and the rear wheel output shaft 14 by the distribution device 12, and The rate is controlled by a distribution controller 15 mainly consisting of a clutch that is engaged by hydraulic pressure. A hydraulic control device 16 for supplying and discharging hydraulic pressure to and from the clutch in this distribution controller 15 and regulating the hydraulic pressure is equipped with a hydraulic circuit shown in FIG. 3, which will be described later, and controls the pressure regulation level and other controls. This is done electrically by a wheel drive electronic control unit (ECU) 17. In addition, in order to correct fluctuations in the pressure regulation level based on acceleration, the four-wheel drive electronic control device 17
An acceleration sensor 18 is connected to.

FIG. 3 shows an example of the main configuration of the hydraulic control device 16, and the hydraulic control device 16 shown here includes an electromagnetic proportional valve 20 and a pressure regulating valve 30. The electromagnetic proportional valve 20 transfers the thrust generated in accordance with the current flowing through the solenoid 21 to the spool 23 via the plunger 22.
A spring 24 is placed on one end of the spool 23, and a spring 24 is placed on the other end of the spool 23 to generate hydraulic pressure corresponding to the axial force acting on the spool 23.The spool 23 has three lands. However, with respect to the pressure receiving area A11 of the central land 25, the land 26 on the spring 24 side
The pressure receiving area A21 is smaller. Also, an oil passage 27 is formed in the central land 25 to communicate the both end surfaces thereof, so that the hydraulic pressure supplied from the input port 28 is applied between the central land 25 and the land 26 on the spring 24 side. It has become. Therefore, this electromagnetic proportional valve 20 has a hydraulic pressure (temporarily referred to as solenoid output pressure) Psol generated at its output port 29 when the inertial force is zero.
is now expressed by equation (1).

Psol = (Fi −Fsp1
)/ΔA1...(
1) Here, Fi is the load by which the plunger 22 presses the spool 23 according to the current flowing through the solenoid 21, and Fsp1
is the elastic force of the spring 24, and ΔA1 is the difference in the pressure receiving area (A11-A21).

[0012] The solenoid 21 is connected to a four-wheel drive electronic control unit 17 that controls the value of current flowing therein.

On the other hand, the pressure regulating valve 30 has a spring 31
The solenoid output pressure Psol is used as a control pressure to act on the spool 32, which is pressed in one direction (upward direction in FIG. 1), in the opposite direction to the spring 31, thereby regulating the pressure. The spool 32 has three lands, and the pressure receiving area A22 of the land 34 on the spring 31 side is smaller than the pressure receiving area A12 of the central land 33. Pressure PL is supplied, and central land 33 is supplied to this input port 35.
An output port 36 which is communicated and cut off by the above is connected to the clutch 19 in the distribution controller 15, and is connected to a return port 37 which is open between the two lands 33 and 34. Therefore, this pressure regulating valve 30
The hydraulic pressure (temporarily referred to as clutch hydraulic pressure) Pc generated at the output port 36 when the inertial force is zero is expressed by equation (2).

Pc=(Psol・A32-F
sp2 )/ΔA2...(2
) Here, A32 is the pressure-receiving area of the face on which the solenoid output pressure Psol acts, Fsp2 is the elastic force of the spring 31, and ΔA2 is the difference in the pressure-receiving areas of the lands 33 and 34 (
A21-A22).

Since the above-mentioned hydraulic control device 16 is mounted on a vehicle, acceleration occurs in the longitudinal direction and the lateral direction when the vehicle is running or when starting or stopping, and the accompanying inertia force is applied to the electromagnetic proportional valve 20 and the adjustment. In the device described above, the acceleration sensor 18 detects the acceleration that affects the pressure regulation level in the pressure valve 30, and based on the detection result, the four-wheel drive electronic control unit 17 The current flowing through the solenoid 21 is corrected to a current value that corrects the influence of acceleration. In other words, when acceleration/deceleration a occurs in the direction of the arrow in FIG.
acts.

F1I=(M1 +M2)・a
…
(3) Here, M1 is the mass of the spool 23, and M2 is the mass of the plunger 22.

Therefore, the solenoid output pressure Psol when acceleration/deceleration a occurs is expressed by equation (4).

Psol = (Fi +F1I−
Fsp1)/ΔA1...(4)
Further, an inertial force F2I expressed by equation (5) acts on the spool 32 of the pressure regulating valve 30.

F2I=m・a

...(5) Here, m is the mass of the spool 32.

Therefore, clutch oil pressure PcI when acceleration/deceleration a occurs is expressed by equation (6), which is obtained by adding a correction term based on inertia force F2I to equation (2) described above.

PcI=(Psol・A32+
F2I-Fsp2 )/ΔA2 (6) That is, the deviation ΔPc from the target oil pressure Pc due to acceleration/deceleration a
is as shown in equation (7).

ΔPc = PcI−Pc
=(A32・F1I/ΔA1
・ΔA2)+F2I/ΔA2
= {m+A32(M1 +M2)/
ΔA1 }a/ΔA2
=K・a
...(7) As is clear from equation (7), the pressure deviation ΔPc based on the acceleration/deceleration a is proportional to the acceleration/deceleration a, with the constant K determined by the structure of the electromagnetic proportional valve 20 and the pressure regulating valve 30 being a proportional constant. Therefore, the four-wheel drive electronic control device 17 sets Pc = PcI
-ΔPc is calculated, and the current corresponding to this oil pressure is applied to the solenoid 21.
It is designed to flow to

FIG. 4 is a flowchart showing a hydraulic pressure control routine by the four-wheel drive electronic control unit 17 in a state of acceleration/deceleration a. In step 1, a target pressure regulation value is read based on the running state of the vehicle, and In step 2, acceleration/deceleration a is detected, and in step 3, a hydraulic correction value ΔPc is calculated based on the detected acceleration/deceleration a. Then, in step 4, the hydraulic pressure correction value ΔP is calculated from the hydraulic pressure PcI generated when the pressure is regulated at the target pressure regulation value in the state of acceleration/deceleration a.
A value Pc is obtained by subtracting c, and a current value i is determined to obtain this oil pressure (step 5). In the linear solenoid valve 20, the current value i flowing through the solenoid 21 is proportional to the generated pressure, and even in the pressure regulating valve 30, which uses the generated oil pressure as the pilot pressure, the generated pressure is proportional to the pilot pressure. Therefore, in the above device, the generated pressure is proportional to the pilot pressure. , as shown in FIG. 5, the clutch pressure Pc is proportional to the current i, so if the target pressure is determined, the current value i can be uniquely determined. In step 6, the thus determined current value i is output, and as a result, the pressure regulation level of the electromagnetic proportional valve 20, and ultimately the pressure regulation level of the pressure regulating valve mechanism consisting of the electromagnetic proportional valve 20 and the pressure regulating valve 30. is set to a value that generates the clutch pressure Pc.

Therefore, in the above-mentioned device, even if an inertial force based on acceleration or deceleration acts, the pressure regulation level is corrected in accordance with the acceleration/deceleration, so that the oil pressure Pc supplied to the clutch 19 remains as desired. As a result, the torque distribution ratio between the front and rear wheels becomes the desired ratio, and favorable power performance can be obtained.

In the above embodiment, the hydraulic control device for a four-wheel drive device was taken as an example, but the present invention can also be applied to a hydraulic control device for other power transmission devices such as an automatic transmission for a vehicle. can do. Further, in the above embodiment, the case where acceleration/deceleration occurs in the axial direction of the valve is explained, but in this invention, the axial direction of the valve and the direction in which the acceleration/deceleration acts may form a predetermined angle. In that case, the value of acceleration/deceleration may be corrected according to the angle between the two.

Further, in the above embodiment, the pressure regulating valve mechanism was constructed by the electromagnetic proportional valve and the pressure regulating valve, but the pressure regulating valve mechanism of the present invention is composed of one valve or three or more valves. It may be composed of.

[0027]

[Effects of the Invention] As is clear from the above explanation, according to the hydraulic control device of the present invention, the pressure adjustment level is corrected according to acceleration/deceleration, so the obtained hydraulic pressure becomes the target pressure, and as a result, It is possible to effectively prevent deviations in the torque distribution ratio between the front and rear wheels, changes in vehicle behavior resulting from this, and worsening of shift shock.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the basic configuration of the present invention.

FIG. 2 is a block diagram showing an example in which the present invention is applied to a hydraulic control device for a four-wheel drive device.

FIG. 3 is a hydraulic circuit diagram showing a pressure regulating valve mechanism in an embodiment of the present invention.

FIG. 4 is a flowchart showing a hydraulic control routine.

FIG. 5 is a diagram showing the relationship between current value and clutch oil pressure.

[Explanation of symbols]

1 Frictional engagement element 2 Pressure regulating valve mechanism 3 Acceleration/deceleration detection means 4 Correction means 16 Hydraulic control device 17 Four-wheel drive electronic control device 18 Acceleration sensor 19 Clutch 20 Solenoid proportional valve 30 Pressure regulating valve

Claims (1)

[Claims] 1. A hydraulic control device for a power transmission device configured to regulate hydraulic pressure supplied to a frictional engagement element by a pressure regulating valve mechanism that regulates the hydraulic pressure to a pressure corresponding to a load acting on a valve body. acceleration/deceleration detection means for determining acceleration/deceleration acting on the valve body in a direction parallel to the acting direction;
A hydraulic control device for a power transmission device, comprising: a correction means for correcting the load applied to the valve body according to the acceleration/deceleration determined by the acceleration/deceleration detection means.