JPH04353029A - Hydraulic controller for power transmission device - Google Patents

Abstract

PURPOSE:To provide cost reduction by reducing the number of part items. CONSTITUTION:An electromagnetic proportional valve 20 and a pressure regulator 30 are arranged in parallel to the direction of acceleration/deceleration (a) based on engine load, and pressure regulating level is changed according to inertial force working upon spools 23, 32 and a plunger 22 to generate hydraulic pressure Pc according to the acceleration/deceleration (a) or the engine load. It is thus possible to make it unnecessary to use a means for detecting the engine load and a means for introducing the detected results into hydraulic pressure.

Description

[Detailed description of the invention]

0001

[Field of Industrial Application] This invention relates to a hydraulic control device for an automatic transmission or a four-wheel drive device for a vehicle, and in particular controls the engagement pressure of a predetermined frictional engagement element according to the load of a drive device such as an engine. This relates to a hydraulic control device that changes.

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

0003

[Problems to be Solved by the Invention] As mentioned above, in power transmission devices such as automatic transmissions and four-wheel drive devices for vehicles,
The hydraulic pressure supplied to the frictional engagement elements is controlled according to the engine load in order to adjust the transmission torque capacity of the frictional engagement elements according to the engine load or to obtain a four-wheel drive state according to the engine load. However, as a means to detect the engine load, a throttle sensor, a torque sensor, an air flow meter to detect the intake air amount, etc. are used as a means to detect the engine load, and a computing unit, actuator, or A throttle cable, etc. is used. Conventionally, a large number of devices are required to detect the engine load and to reflect the detection results in the oil pressure, which not only increases the number of parts but also increases the man-hours required to assemble them. There were many problems, such as an increase in the cost of the hydraulic control device.

The present invention was made against the background of the above-mentioned circumstances, and it is an object of the present invention to provide a low-cost hydraulic control device with a reduced number of parts.

[0005]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides that a power transmission device that transmits power output from a drive device has a frictional engagement element, and that any one of the frictional engagement elements has a frictional engagement element. In a hydraulic control device for a power transmission device in which elements are configured to be engaged by hydraulic pressure according to the load of the drive device, a pressure regulating valve mechanism that regulates the hydraulic pressure supplied to the frictional engagement element adjusts the hydraulic pressure applied to the valve body. and a load to face each other and adjust the hydraulic pressure according to the load, and the inertia force based on the acceleration/deceleration generated in response to the load of the drive device is applied to the valve in a direction parallel to the acting direction of the load. The pressure regulating valve mechanism is installed so as to act on the body, and the pressure regulating level of the pressure regulating valve mechanism changed by the acceleration/deceleration becomes a pressure regulating level corresponding to the load of the drive device that causes the acceleration/deceleration. It is characterized by being configured.

[0006]

[Operation] The power transmission device targeted by the present invention includes a frictional engagement element that is engaged by hydraulic pressure according to the load of a drive device such as an engine, and adjusts the hydraulic pressure supplied to the frictional engagement element. In the pressure regulating valve mechanism, when acceleration/deceleration occurs due to an increase/decrease in the load of the drive device, the pressure regulation level changes depending on the acceleration/deceleration. In other words, when acceleration/deceleration occurs, an inertial force based on the acceleration/deceleration acts on the valve body of the pressure regulating valve mechanism in a direction parallel to the direction in which the load that determines the pressure regulating level acts, and therefore, the inertial force The pressure regulation level changes by being added to the load that determines the pressure regulation level. Therefore, the hydraulic pressure supplied to the frictional engagement element becomes a pressure that reflects the load of the drive device. In other words, the pressure can be adjusted as expected without requiring a detection means for detecting the load of the drive device or a means for reflecting the detection result on the oil pressure.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIGS. 1 and 2 show an embodiment of the present invention, and the example shown here deals with a four-wheel drive device 1 shown in FIG. 2 as a power transmission device. That is, the four-wheel drive device 1 uses the output shaft of a transmission 3 connected to an engine 2 as an input shaft 4, and this input shaft 4 is connected to a carrier 6 of a planetary gear mechanism 5, which is a distribution mechanism. has been done. In this planetary gear mechanism 5, a ring gear 7 is connected to a rear wheel output shaft 8, a sun gear 9 is connected to a drive sprocket 10, and a front wheel output shaft 13 is connected to a driven sprocket 12 connected to the drive sprocket 10 by a chain 11. connected. A differential limiting clutch 14 is provided between the carrier 6 and the sun gear 9 to limit the differential operation of the planetary gear mechanism 5 and appropriately adjust the torque distribution ratio between the front and rear wheels. This differential limiting clutch 14, as shown by the symbol in FIG.
The clutch 14 is a multi-disc clutch that is engaged by hydraulic pressure, and a hydraulic control device 15 that supplies hydraulic pressure to the clutch 14 generates hydraulic pressure in accordance with acceleration/deceleration caused by changes in engine load.

FIG. 1 shows an example of the main configuration of the hydraulic control device 15, and the hydraulic control device 15 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).

The above electromagnetic proportional valve 20 is connected to the spool 2.
The central axis of the engine 3 coincides with the direction of the acceleration/deceleration a (direction of the arrow in FIG. 1) as the engine load changes. Note that the reference numeral 40 in FIG. 1 indicates an electronic control unit (ECU), which controls the current value given to the electromagnetic proportional valve 20 according to calculation results based on various data.

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.
The output port 36 that is communicated and disconnected by the clutch 1
4, and is connected to a return port 37 that is open between the two lands 33 and 34. Therefore, in 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 area of the lands 33 and 34 (
A21-A22).

The pressure regulating valve 30 is also arranged so that the central axis of its spool 32 coincides with the direction of the acceleration/deceleration a caused by changes in engine load.

In the above-mentioned hydraulic control device 15, the electromagnetic proportional valve 20 and the pressure regulating valve 30 are arranged to face the acceleration/deceleration rate a accompanying a change in the engine load, so that the adjustment that reflects the acceleration/deceleration rate a is performed. In other words, the pressure is adjusted to reflect the engine load. in particular,
When acceleration/deceleration a corresponding to the engine load occurs in the direction of the arrow in FIG. 1, an inertial force F1I expressed by equation (3) acts on the spool 23 of the electromagnetic proportional valve 20.

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

Pc = (Psol ・A32+
F2I-Fsp2 )/ΔA2 (6) As is clear from equation (6), the oil pressure Pc supplied to the clutch 14 is expressed as a linear function of the acceleration/deceleration a, as illustrated in FIG. Since the acceleration/deceleration rate a depends on the engine load, the clutch oil pressure Pc becomes a pressure that reflects the engine load. That is, in the above hydraulic control device 15, the predetermined acceleration/deceleration a (i.e. engine load)
When , the above constant terms (i.e., each value based on the structure of the valves 20, 30) M1, M2, m,
Fsp1, Fsp2, ΔA1, and ΔA2 are determined.

Therefore, in the above-mentioned hydraulic pressure control device 15, the pressure regulation level of the clutch hydraulic pressure Pc changes according to the engine load, and differential restriction suitable for each engine load state can be performed, and such hydraulic pressure control is possible. Since a sensor for detecting engine load or a similar mechanism is not required to perform this, the hydraulic control device 15 can be made small with a small number of parts.

In the above embodiment, each spool 23, 32, which is a valve body, is made to completely match the direction of the acceleration/deceleration, but in this invention, the point is that the acceleration/deceleration according to the engine load is the same as the direction of the valve body. The valve body may be inclined with respect to the direction of acceleration/deceleration as long as it acts on the body. In that case, the value of the inertial force may be corrected according to the inclination angle. Further, in the above embodiment, the pressure regulating valve mechanism was configured by the electromagnetic proportional valve and the pressure regulating valve, but the pressure regulating valve mechanism of the present invention may be composed of one valve, or three or more valves. You can leave it there. Further, the hydraulic control device of the present invention is not limited to a four-wheel drive device, and is a power transmission device in which inertial force acts due to the load of a drive device such as an engine such as an automatic transmission for a vehicle. It can be applied to a hydraulic control device for equipment.

[0023]

Effects of the Invention As is clear from the above description, in the hydraulic control device of the present invention, the pressure regulating valve mechanism is arranged so that the acceleration/deceleration caused by the load of the drive device acts on the valve body, and the Since the configuration is configured to change the pressure adjustment level using inertia force to obtain oil pressure according to the load on the drive device, there is no need for a means to detect the load on the drive device such as a throttle sensor or an air flow meter, and a means to reflect the detection results in the oil pressure. Therefore, according to the present invention, it is possible to obtain a small, low-cost hydraulic control device with a small number of parts.

[Brief explanation of drawings]

FIG. 1 is a hydraulic circuit diagram showing an embodiment of the present invention.

FIG. 2 is a skeleton diagram showing an example of a power transmission device targeted by an embodiment of the present invention.

FIG. 3 is a diagram showing the relationship between acceleration/deceleration and clutch oil pressure according to the present invention.

[Explanation of symbols]

1 Four-wheel drive device 2 Engine 14 Differential limited clutch 15 Hydraulic control device 20 Solenoid proportional valve 23 Spool 30 Pressure regulating valve 32 Spool

Claims (1)

[Claims] Claim 1: A power transmission device that transmits power output from the drive device has a frictional engagement element, and one of the frictional engagement elements is configured to be engaged by hydraulic pressure depending on the load of the drive device. In a hydraulic control device for a power transmission device, a pressure regulating valve mechanism that regulates the hydraulic pressure supplied to the frictional engagement element is arranged such that the hydraulic pressure applied to the valve body and the load are opposed to each other, and the pressure is regulated to a hydraulic pressure corresponding to the load. and the pressure regulating valve mechanism is installed so that an inertial force based on acceleration/deceleration generated in accordance with the load of the drive device acts on the valve body in a direction parallel to the acting direction of the load,
Hydraulic pressure of a power transmission device, characterized in that the pressure regulation level of the pressure regulating valve mechanism changed by the acceleration/deceleration is a pressure regulation level corresponding to the load of the drive device that causes the acceleration/deceleration. Control device.