JPS60179554A - Pressure-regulating valve - Google Patents

Abstract

PURPOSE:To prevent a frictional element from insufficiency of its torque capacity, by increasing the pressure of oil, regulated by a pressure-regulating valve, higher when the oil is at a high temperature than the pressure of oil in an ordinary case. CONSTITUTION:A pressure-regulating valve 30 provides a temperature sensing spring 40 having a characteristic in which a trend of its tension decreasing a drain quantity is increased larger, when a temperature is higher than a predetermined value, than when the temperature is lower than the predetermined value. In this way, a frictional element can be prevented from insufficiency of its torque capacity generated in accordance with a decrease of viscosity because the regulated pressure of oil when it is at a high temperature can be increased.

Description

[Detailed description of the invention] (b) Technical field The present invention relates to a pressure regulating valve.

(B) Prior Art As a conventional pressure regulating valve for regulating the oil pump discharge pressure, for example, the regulator valve shown in JP-A-56-109942 F "Automatic Transmission System for Automobiles" (filed on January 16, 1980) is used. be. This regulator valve is
It has a function to adjust the oil pump discharge pressure according to the throttle response and pressure. However, when such a conventional pressure regulating valve is used in a hydraulic control device of an automatic transmission, for example, a device is installed to correct the pressure regulating function according to the oil temperature.
As a result, when the oil temperature is high, the viscosity of the oil decreases, and the amount of oil leaking from seals and fittings increases, causing the oil pressure to drop below the specified value and causing friction in clutches, brakes, etc. There has been a problem in that in order to prevent the occurrence of insufficient torque capacity of the element, the line pressure may have to be set slightly higher when the oil temperature is low.

(c) Purpose of the Invention The present invention provides a low oil pressure system that ensures the necessary oil pressure even at high temperatures when the viscosity of the oil has decreased, and does not cause insufficient torque capacity of the friction element. The object of the present invention is to provide a pressure regulating valve that prevents line pressure from increasing unnecessarily when the temperature is high.

(D) Structure of the Invention The present invention provides for increasing the oil pressure regulated by the pressure regulating valve to a higher level than normal when the oil temperature is high.
Achieve the above target. To this end, in the present invention, a temperature-sensitive spring whose phase changes depending on the temperature is used for the pressure regulating valve. That is, the pressure regulating valve according to the present invention is provided with a temperature-sensitive spring made of a shape memory alloy or the like that applies force to the spool. When the temperature is higher than a predetermined value, the temperature increases more than when the temperature is lower than the predetermined value.

(e) Examples Examples of the present invention will now be described with reference to FIGS. 1 and 2 of the accompanying drawings.

(First Embodiment) FIG. 1 shows a first embodiment of the present invention. The regulator valve 1o, which is a pressure regulating valve, includes a spool 14 inserted into a valve hole 12, a spring 16 arranged at the upper end of the spool 14 in FIG. The spring 18 has a shape memory alloy spring 19 (temperature-sensitive spring). The valve hole 12 has ports 12a to N12f. port 1
2a and 12c are drain ports. Port 12b
and 12d are connected to a line pressure oil passage 22 to which oil discharged from the oil pump 2o is supplied. The port 12e is a port from which oil is discharged from the port 12d, and the oil discharged to the port 12e is supplied to, for example, a torque converter via an oil passage 24. The bow) 12f is connected to an oil passage 26 to which throttle corresponding pressure (throttle pressure, throttle modulated pressure that is further adjusted to the throttle pressure, etc.) is supplied.The spool 14 is connected to lands 14a to 14d.
have. Lands 14b, 14c, and 14d have the same diameter, and land 14a has a smaller diameter than these. A hydraulic pressure of 12b acts on the pressure receiving portion formed between the land 14a and the land 4b. The spring 16 always exerts a constant downward force on the spool 14 in FIG. The spring 18 is connected to the spool 14 in a first
In the figure, a constant upward force is applied. The shape memory alloy spring 19 exerts a relatively small upward force (this force) on the spool 14 in FIG. The force is almost balanced with the spring 16), but if the oil temperature is higher than a predetermined value (for example, around 140°C), it expands and the force acting on the spool 14 becomes larger. It is.

Next, the operation of this embodiment will be explained. Two downward forces act on the spool 14 of the regulator valve IO: the force due to the hydraulic pressure acting on the boat 12b and the force due to the spring 1G, while the force due to the throttle response acting on the boat 12f, the force due to the spring 18, and the force due to the spring 1G act on the boat 12f. Three upward forces act: the forces of the shape memory alloy spring 19. The spool 14 transfers oil from port 12d to port 1 so as to balance this downward force and upward force.
2e and port 12c to perform a well-known pressure regulating action. In a steady state of use where the oil temperature is relatively low, the shape memory alloy spring 19 exerts a relatively small upward force on the spool 14. regulator valve l
O performs the above-mentioned pressure regulating action based on this relatively small force of the shape memory alloy spring 19, and regulates the line pressure to the normal characteristic as a reference. The torque capacity of friction elements such as clutches and brakes is determined based on the characteristics of this reference line pressure.

When the oil temperature is very high (e.g. higher than 140°C) such as during heavy load continuous operation, the force of the shape memory alloy spring 19 of the regulator valve IO is reduced when the oil temperature is in a steady state. becomes larger than For this reason, the upward force acting on the spool 14 in FIG. 1 increases, and the hydraulic pressure of the port h12b increases to compensate for this. That is, the line pressure of the oil passage 22, which is regulated by the reculator valve IO, increases. Even if the viscosity of the oil decreases due to an increase in the oil temperature, the set value of the line pressure itself increases to compensate for the drop in oil pressure due to the drop in viscosity, so the required oil pressure is ensured. By doing so, the automatic transmission can be brought into a running state without causing insufficient torque capacity of the friction elements even at high temperatures.

(Second Embodiment) FIG. 2 shows a second embodiment of the present invention. This pressure regulating valve 3
0 is the spool 34 inserted into the pulp hole 32 and the second
Spring 36 located above spool 34 in the figure
and a spring 38 and a shape memory alloy spring 40 (temperature-sensitive spring) arranged below the spool 34 in FIG. Pulp hole 32 is port 32
It has a to 32e. bow) 32a and port 32
C communicates with an oil passage 27 to which regulated hydraulic pressure is supplied. Hydraulic pressure, which is the source pressure, is supplied to the port 32b from the oil passage 42. Ports 32d and 32e are drain ports. The spool 34 has lands 34a and 34b of the same diameter. The axial dimension between lands 34a and 34b is approximately equal to the wall distance between ports 32b and 32d. Spring 36 is spool 34
In Fig. 2, a constant downward force is applied to the

Spring 38 exerts a constant upward force on spool 34 in FIG. The shape memory alloy spring 40 exerts a relatively small upward force on the spool 34 during regular use when the oil temperature is relatively low, but when the oil temperature rises above a predetermined value, it expands in the axial direction. This is so that the force acting on the spool 34 is increased. With such a configuration, the pressure regulating valve 30
A predetermined hydraulic pressure is regulated in the oil passage 27 based on the difference between the upward force obtained by adding the force of the spring 38 and the force of the shape memory alloy spring 40, and the downward force caused by the spring 36. When the oil temperature is higher than a predetermined value, the force of the shape memory alloy spring 40 is greater than when the oil temperature is low, so the regulated oil pressure becomes higher. Therefore, oil passage 27
When the oil pressure is connected to a friction element such as a clutch or a brake, the oil pressure supplied to the friction element increases when the oil temperature is high, and it is possible to prevent oil pressure from decreasing due to a decrease in viscosity. In the above embodiment, the temperature-sensitive spring is made of a shape-memory alloy, but it is not limited to this, and any material that changes phase depending on the oil temperature may be used (for example, a bellows filled with wax).

(f) As described in detail, according to the present invention, the hydraulic pressure of the oil passage to be pressure regulated is applied to the spool in a predetermined direction,
In a pressure regulating valve that regulates the oil pressure in the oil passage by increasing or decreasing the drain amount of the oil passage depending on the magnitude of the force acting on the spool in the predetermined direction, the pressure adjustment valve adjusts the oil temperature to apply a force to the spool. A variable temperature-sensitive spring is provided, and the temperature-sensitive spring acts on the spool in a direction opposite to the predetermined direction when the temperature is higher than a predetermined value, and when the temperature is lower than a predetermined value. Since it has the property of increasing more than the acting force, it is possible to increase the regulating pressure when the temperature is high, and prevent the lack of torque capacity of the friction element that occurs due to a decrease in viscosity. When the viscosity of the oil is high, only the minimum amount of oil pressure is required. Further, in an embodiment in which the temperature-sensitive spring is made of a shape memory alloy, in addition to the above-mentioned effects, it is particularly advantageous in terms of space and cost.

[Brief explanation of drawings]

FIG. 1 is a diagram showing a first embodiment of the invention, and FIG. 2 is a diagram showing a second embodiment of the invention. ■0-・Regulator valve, 12m *Fist/<Shib hole, ■4-・Spool, 16-・Skewer spring, 1
8...Spring, 19--Shape, shape memory alloy spring, 20...Oil pump. 22.24.26 - Oil line, 3011... Pressure regulating valve, 32... Lube hole, 34... Spool, 36... Fist spring, 38... Fist spring, 40... Shape memory Alloy spring. Figure 1 Figure 2

Claims (1)

[Claims] 1. The hydraulic pressure of the oil passage to be regulated is applied to the spool in a predetermined direction, and the drain amount of the oil passage is increased or decreased depending on the magnitude of the force acting on the spool in the predetermined direction. The pressure regulating valve that regulates the oil pressure in the oil passage is equipped with a temperature-sensitive spring that changes phase depending on the oil temperature in order to apply force to the spool. 1. A pressure regulating valve characterized in that a force acting on the spool in a direction opposite to the predetermined direction when the temperature is higher than the predetermined value is greater than a force acting on the spool when the temperature is lower than the predetermined value. 2. The pressure regulating valve according to claim 1, wherein the temperature-sensitive spring is made of a shape memory alloy.