RU91610U1 - PRESSURE CONTROL VALVE IN HYDRAULIC DEVICES - Google Patents

Abstract

1. A pressure control valve, comprising a housing with a supply pressure supply channel, a drain channel, an adjustable pressure output channel, a spool installed in the housing to form end cavities, one of which is connected to a supply pressure supply channel and, through a control valve, to a drain channel, the spool return mechanism in the form of a compression spring, characterized in that the spool return mechanism is additionally equipped with a hydraulic cylinder formed by a cavity formed in the spool and placed therein with the possibility of interaction with the end face of the body by the plunger, while the spool cavity is in communication with the output channel of the adjustable pressure, the second end cavity of the valve is constantly connected to the drain channel. ! 2. The valve according to claim 1, characterized in that the compression spring is located between the plunger and the valve in the cavity of the latter.

Description

The utility model relates to the field of mechanical engineering, namely to means for controlling pressure in hydraulic devices.

Known pressure regulators, for example pressure reducing valves of constant pressure (Bashta T.M. Hydraulic actuator and hydropneumatics, M. Mechanical Engineering, 1972, p.103). This valve contains a housing with a supply pressure supply channel, a drain channel, an output \ channel and an internal bore, in which a spool is placed that changes the flow section between the pressure supply channel and the output channel. On the moving part of the valve, a spring acts on one side, striving to increase the bore, and on the other hand, pressure in the outlet channel, which reduces the bore. A stabilized pressure is maintained in the output channel, the value of which is set by the spring tension force. The main disadvantage of this regulator is the inability to quickly control the input pressure.

The closest in design and purpose is a valve with electromagnetic control, for example a valve type XRP 044 from Comatrol (www.comatrol.com see figure 1), adopted as a prototype. This valve (Fig. 1) has a housing 1 with a supply pressure supply channel 2, a drain channel 3, an adjustable pressure output channel 4. A spool 5 is installed in the housing to form end cavities, one of which is connected to the supply pressure supply channel and through a control valve with drain channel. The valve is equipped with a spool return mechanism.

The spool 5, depending on its position, connects the output channel of the controlled pressure 4 either to the supply pressure supply channel 2 or to the drain channel 3. One of the end cavities is constantly connected to the pressure supply channel 2 and communicates with the drain through the control valve 7, the force on which is set by the current of the control electromagnet 8. Another end cavity is connected by a channel 9 to an output channel of an adjustable pressure 4, a spring 6 is located in it, which serves as a return mechanism of the spool. The position of the spool is determined by the balance of the forces acting on it: on the one hand, the pressure specified by the force of the control electromagnet, and on the other hand, the pressure formed in the output channel of the adjustable pressure and the force of the spring return spool.

The disadvantages of the known design include the inability to realize the full supply pressure at the output due to the influence of the return spring and the equality of the end areas of the spool. On the one hand, the force acting on the spool is equal to the control pressure multiplied by the area of the end of the spool. The maximum control pressure in this case may be equal to the supply pressure. The force acting on the opposite end of the spool is equal to the product of the control output pressure and the area of the spool end and the force of the return spring. Therefore, the output control pressure is always less than the supply pressure, which reduces the efficiency (efficiency) of the hydraulic control system, for example, in transmission clutch and brake clutch control systems.

The objective of the utility model is to increase the efficiency of the hydraulic control system by ensuring full supply pressure at the valve outlet, achieved after smooth regulation.

The specified technical result is achieved by the fact that in the valve for controlling pressure in hydraulic devices containing a housing with a supply pressure supply channel, a drain channel, an adjustable pressure output channel, a spool installed in the housing with the formation of end cavities, one of which is connected to the pressure supply channel supply and through a control valve with a drain channel, the return mechanism of the spool in the form of a compression spring, the latter is additionally equipped with a hydraulic cylinder formed in the spool cavity and arranged therein to interact with the plunger end of the body, wherein the cavity in the slide valve communicates with the controlled pressure output channel, the second end of the valve chamber is connected to the discharge channel continuously. In addition, a compression spring is installed between the plunger and the spool in the cavity of the latter.

The essence of the utility model is illustrated by drawings, where:

- figure 2 shows a valve for controlling pressure;

- figure 3 is a graph of the dependence of the output pressure on the control signal.

The valve (figure 2) comprises a housing 1 with a supply pressure supply channel 2, a drain channel 3 and an adjustable pressure output channel 4. In the housing 1, a spool 5 is placed with the formation of end cavities 6 and 7. The cavity 6 is connected to the supply pressure supply channel 2, having a throttle 8, and through a control valve 9 with an electromagnet 10 to the drain channel 3. The spool 5 is equipped with a return mechanism 11 in the form of a hydraulic cylinder, which is a plunger 12 located in the end cavity 7 in the spool 5 of the cavity 11. The hole 11 is connected to the hole m 13 in the spool 5 with the output channel of the adjustable pressure 4. The plunger 12 at one end is in contact with the end face of the housing 1, and the other with the compression spring 14, which in turn rests on the spool 5. The end cavity 7 is connected to the drain channel 3.

The valve operates as follows. In the absence of current in the winding of the electromagnet 10, the valve 9 freely communicates the cavity 6 with the drain channel 3, and the pressure in it is close to the drain pressure, since the pressure drop on the throttle 8 is almost equal to the supply pressure. In the end cavity 7, the pressure is also close to the discharge pressure. Under the action of the spring 14, the spool 5 moves to the leftmost position (Fig. 2), connecting the output channel 4 to the drain channel 3. The feed pressure supply channel 2 is isolated by the spool 5 from the output channel 4. The pressure in the friction clutch cylinder (not shown in Fig. 2 ) is close to zero. When a current is supplied to the winding of the electromagnet 10, a force determined by the magnitude of the current acts on the valve 9, the fluid flow through the inductor 8 decreases, and a pressure proportional to the force created by the electromagnet 10 is established in the cavity 6. When the force on the spool 5 created by the pressure in the cavity 6 exceeds the force of the spring 14, the spool 5 is shifted to the right, opening the fluid path from the supply pressure channel 2 to the output channel 4. The pressure in the output channel 4 through the hole 13 in the spool 5 is transmitted to the cavity 11 hydraulic cylinders. Spool 5 will take a position in which the forces acting on it to the right and left will be balanced. The pressure in the output channel 4 is determined by the magnitude of the current of the electromagnet 10, the force of the spring 15 and the ratio of the areas of the left end of the spool 5 and the end of the plunger 12. Since the area of the left end of the spool 5 is larger than the area of the end of the plunger 10, at certain ratios of these areas and the value spring force 15 pressure in the output channel 4 will be equal to the supply pressure. With a further increase in the current of the electromagnet 10 and, accordingly, an increase in pressure in the cavity 6, the balance of forces acting on the spool 5 will be disturbed, and the spool 5 will move to the extreme right position, providing a reliable connection of the output channel 4 with the channel for supplying pressure 2 and supplying full pressure supply to the clutch hydraulic cylinder.

A graph of the pressure in the output channel 5 on the current magnitude of the electromagnet 10 is shown in Fig.3. The characteristic has sections — the insensitivity zone OA, the step for continuously regulating the pressure AB and the saturation section for the aircraft, in which the pressure in the output channel 4 does not depend on the magnitude of the current of the electromagnet 10 and is equal to the supply pressure. The length of the section AB is determined by the ratio of the areas of the left end of the spool 5, the end of the plunger 12 and the spring force 14.

The application of the proposed device allows to realize the full supply pressure at the outlet and reduce the supply pressure while maintaining the outlet pressure unchanged, which will lead to an increase in the hydraulic system efficiency.

Claims (2)

1. A pressure control valve, comprising a housing with a supply pressure supply channel, a drain channel, an adjustable pressure output channel, a spool installed in the housing to form end cavities, one of which is connected to a supply pressure supply channel and, through a control valve, to a drain channel, the spool return mechanism in the form of a compression spring, characterized in that the spool return mechanism is additionally equipped with a hydraulic cylinder formed by a cavity made in the spool and placed therein with the possibility of interaction with the end face of the plunger body, while the spool cavity is in communication with the output channel of the adjustable pressure, the second end cavity of the valve is connected to the drain channel constantly. 2. The valve according to claim 1, characterized in that the compression spring is located between the plunger and the valve in the cavity of the latter.