JPS63188554A - Flow regulating valve for hydraulic brake and brake facility with said valve - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a valve for hydraulic brakes, which carries out a regulation of the fluid flow, the valve always establishing a pressure level in accordance with the braking level required for the hydraulic brake. .

The invention also relates to vehicle braking equipment using said valve.

As is known, hydraulic braking systems are based on the function of supplying hydraulic pressure to a braking mechanism to achieve a braking action.

In vehicles with lightweight and minimally equipped hydraulic braking systems, cylinders are always used, the piston of which is driven directly by the user through the brake pedal. The movement of the piston generates a pressure in the chamber of the cylinder, which pressure is transmitted to the same braking system through the corresponding connecting flap.

In heavy vehicles it is clearly necessary to generate additional fluid pressure in the braking mechanism. Therefore, said method is not valid because the pressure to be applied on the brake pedal is higher than the physical possibility of the user.

Therefore, it is common to turn to so-called "servo brakes", where the energy of the vehicle is used to drive a braking mechanism, with the brake pedal acting as a mere control element for the energy applied to said braking mechanism.

Although this solution is perfectly adequate at the level of relatively small vehicles, it does not provide adequate facilities when dealing with heavy vehicles such as trucks and other road vehicles. The solution commonly used in this range is therefore moved to a completely different range, specifically by using electric brakes.The present invention provides a flow regulating valve for hydraulic brakes. Enables the use of hydraulic brakes on heavy vehicles with complete reliability, functionality and operability.

Therefore, and in a more specific embodiment, the oil is circulated in a closed circuit by the use of a pump that propels oil entering from a supply tank and returned to said tank again in the brake inactive position. The pump communicates with the brake mechanism, and due to the presence of the regulating valve on the brake mechanism, it has no such effect, i.e. in the inactive position, and generates excessive pressure in the brake mechanism in said position. Repeat without overturning to allow free flow of fluid back into the first reservoir. Said pump is continuously actuated by the traction element of the vehicle, but in fact in the inactive position of the braking system the energy consumption is zero and the movement of the oil performs its action practically without any resistance.

On the contrary, during braking, said valve more or less closes the oil return hole to the supply tank, and this closure therefore imposes an overload on the braking mechanism, since the flow supplied by the pump tries to remain constant. generates pressure. As a result, a brake is applied, which brake is regulated by a closure more or less set by a valve at said return outlet of the oil.

It is therefore clear that when the valve is fully closed, the entire pressure generated by the pump is supplied to the braking system and the braking force is at its maximum.

In a more specific PJ, the valve communicates with a cylindrical chamber in which a fluid propulsion pump is associated, the cylindrical chamber having holes radially returning oil to the supply tank of the pump. provided. A piston is housed in the chamber, which leaves the return hole completely free for oil in the inactive position of the brake system.

The piston is axially movable and more or less closes off the bore via an axis that closely traverses the closed base of the cylindrical chamber opposite the pump communication. The shaft passes in the direction of the drum and is physically integrated into the cylindrical chamber.

The drum is fitted with a membrane or diaphragm at an intermediate level, to which the shaft is centrally fixed. Said shaft, and thus the piston, is pushed towards the valve closing position opposite the shaft position by the action of a spring placed in a chamber bounded in the drum by a diaphragm, but the tension of said spring is applied to the other chamber, i.e. , is counteracted by the presence of pressurized air in the chamber in which the shaft is housed and in which it operates.

The chamber containing the spring is under ambient pressure and is therefore in proper communication with the outside world. The lower pressure chamber, on the other hand, is provided with a conduit, energized by a corresponding drive, which allows pressurized air to be introduced into or discharged from said chamber. There, in the presence of pressurized air, the action of the spring is overridden and the valve piston assumes its maximum retracted inoperative position. When the lower chamber of one drum loses its pressure, a spring contained in the other chamber is actuated, causing a piston movement toward a partially or fully closed position. The degree of closure varies according to the pressure level maintained in the chamber of the drum opposite the location of the spring.

An axial hole is provided to ensure that the fluid pressure generated by the pump does not interfere with the axial movement of the piston. The fluid hole extends towards the origin of the shaft and opens in said shaft to establish communication between the two bases of the piston. The pressure present on the lower surface of the piston is then transmitted to its upper surface with the same magnitude, so that the pressure generated by the pump does not influence the movement of said piston in one direction or the other.

In the inoperative position of the '\'I brake system according to the above structure,
Pressure is applied in a drum chamber separate from that in which the spring is located, which pressure acts against said spring and moves the diaphragm against said spring to hold the piston in the retracted position, where the cylindrical The radial holes provided in the chamber are completely free for the return flow of the oil propelled by the pump into its supply tank.

When acting on the corresponding drive, the air pressure in the corresponding chamber of the drum is reduced. The piston advances in its cylindrical chamber towards the pump with an amount according to said pressure drop, more or less closing off the oil return hole to the supply tank of the pump. That blocks the outlet and creates excessive pressure in the fluid communication path between the pump and the brake system, correspondingly activating the brake. The magnitude of the braking force is the same as the large pressure drop in the corresponding chamber of the drum up to the limit position corresponding to maximum braking. The pressure drop across the drum is then total and the piston therefore completely closes the radial return hole of the oil to the supply tank of the pump.

If necessary, in particular according to the weight of the vehicle, a hydraulic brake flow regulating valve is applied. The lower chamber of the drum is in constant communication with the atmosphere, and one chamber is equipped with a spring.
The corresponding inflow and outflow of air is energized by the corresponding drive. Due to the action of the spring, a pressing force is normally maintained in the chamber, which is partially or completely nullified during braking.

The present invention also relates to brake equipment provided with the regulating valve. The hydraulic pumps are used as generators of brake pressure, and complete control and functional regulation of such pumps is achieved in the installation, keeping them all continuously in an equilibrium position.

Accordingly and in a more specific embodiment, the equipment comprises a first pump controlled by a valve or the like as described above, to which a second hydraulic pump is connected, in particular a second pump A pressurizing inlet is connected to the outlet of the first pump, which hydraulic pumps are formed in a hydraulic circuit with a corresponding fluid supply tank and a corresponding radiator.

Complementarily, a bypass valve is installed between the two pumps, which is controlled by the main valve, so that the two valves communicate through corresponding conduits.

In a more specific embodiment, when the main or regulating valve is in the closed position, in which position the first pump supplies a corresponding pressure to the brake mechanism, and the excess pressure generated in said main valve is transferred to the corresponding conduit. and is transmitted to the bypass valve to close it. This second pump thereby transmits its pressure to the brake mechanism. On the other hand, the pressure disappears when the main valve opens and the fluid is free to return to the tank in a closed circuit. The pressure drop present in said main valve automatically opens the side valves communicating with the second pump, and a simultaneous pressure drop in those valves and a simple oil circulation without any pressure transmission to the brake mechanism occur. arise.

From the above, it can be seen that with this construction the two pumps associated with the brake equipment, and in that case all the pumps associated with said equipment, are synchronized and have perfectly balanced pressures and perfect coordination of the brakes during their operation. I can see that it works.

BRIEF DESCRIPTION OF THE DRAWINGS To supplement the following description and to assist in a better understanding of the nature of the invention, a set of illustrative and non-limiting drawings is attached as part of this specification.

FIG. 1 shows how the flow regulating valve is constructed, according to which the cylindrical chamber l is connected to the pump 3 at one of its ends, in particular at the end 2, and in a tight fit. is fixed. When the vehicle is driven by its traction device, the pump 3 is always in operation. The pump receives fluid, in particular oil, from the supply tank through the inlet 4 and is propelled towards the inside of the chamber 1 . The fluid normally returns to the vessel through radial holes 5 provided in the wall near the outlet 2 of the chamber 1. The liquid hole 5 communicates said chamber 1 with a reservoir by a suitable conduit. Preferably, the conduit is provided with a heat sink to suitably cool the fluid.

Inside the cylindrical chamber 1 there is a piston 6 which cooperates with a seal 7 and is in close contact with said chamber. The piston 6 has a conical front surface 8 and is located behind the oil outflow hole 5 in the normal state, i.e. when the brake is not activated, allowing free outflow of the oil.

This piston 6 has a shaft 9 fixed at its opposite end, the longitudinal extension of the shaft intersecting the closed base 10 of the cylindrical chamber 1 cooperating closely enough with the seal 11 to allow the drum 12 to It has been extended to The drum 12 is provided with two chambers 13 and 14 cooperating with an intermediate membrane or diaphragm 15 therein.

The shaft 9 is fixed to the liquid film by two small plates 16 and mounting screws 17. Said shaft 9 is held in a chamber 13, while in the chamber 14 of the drum a diaphragm 15 is fitted in the direction of protrusion of the shaft towards the inside of the cylindrical chamber 1, i.e. to close the oil outflow hole 5, shown in broken lines in the drawing. A spring 18 is provided which tends to deform the membrane 15 in the direction of the axial movement of the piston 6 towards its position.

The drum 12 is connected by screws 19 as shown in the drawings.
It is physically integrated into the base of the cylindrical chamber 1.

The chamber 14 in which the spring 18 is provided is constantly in communication with the atmosphere and is therefore under atmospheric pressure. On the other hand, the chamber 13 communicates with an air inlet/outlet tube 20 energized by a corresponding drive, so that in the inoperative position of the assembly the pressurized air in the chamber 13 is
8 holds the piston 6 in the inactive position indicated by the solid line 6 in the drawing.

To activate the brake mechanism, it is sufficient to activate the drive 20 to reduce the pressure present in the chamber 13 and to displace the piston 6 to more or less close the oil outlet hole 5.

Closure of hole 5 creates an overpressure at the pump outlet communicating with the brake mechanism. As a result, the actuation of the brake mechanism is proportional to this overpressure of the fluid at the pump outlet and thus to the level of closure of the oil return hole 5 towards the supply tank.

To ensure that the oil pressure at the outlet of the pump 3 does not interfere with the normal movement of the piston 6, a
An axial bore 21 is provided which opens at and communicates between the front face 8 of the piston and a chamber 23 defined between said piston 6 and the closed base 10 of the cylindrical shape 1. Through these holes 21 , 22 the pressure between the ends of the piston is released, and the piston is only influenced by a pressing force in one or the other direction against the shaft 9 .

Also, as mentioned above, the chamber 13 can also communicate directly with the atmosphere. In this case, a drive 20 communicates with the chamber 14 of the drum, and a pressing force is applied to said chamber 14 in order to counteract the action of the spring 18 .

In any case, as in the stable position shown in the drawings, the drive power of the pump is inactive for the braking device when the oil is free to return through the hole 5 in a closed circuit. When actuating the drive device 20 to reduce the pressure in the chamber 13 or exerting a pressing force in the chamber 14, the spring 18 pushes the shaft 9 and the force moves the piston 6 into the cylindrical chamber 1 by an amount corresponding to said pressure reduction. move inside. Therefore, the piston has an oil outlet hole 5.
more or less, and that closure creates an overpressure that varies proportionally at the pump outlet. That overpressure is transmitted to the brake system, so that it acts on the brake system with an amount proportional to its effect on the drive device 20.

Obviously, when the brake is suddenly required, the pressure in the chamber 13 is completely dissipated, and the piston 6 then moves towards the fully closed position with respect to the bore 5, which is shown in broken lines in the drawing. On the other hand, when it is desired to obtain a gradual and continuous braking effect, for example when descending a slope, the piston is held in a closed position at an intermediate level with respect to the bore 5. Generate moderate pressure in the braking system according to the special requirements of the case.

Further, in vehicle brake equipment, referring to the structure described above and FIG. 2 for this flow regulating valve made in accordance with the object of the present invention, the main pump 101 similar to the pump 3 in FIG. is designed to operate continuously during the use of the motor of the vehicle in which it is installed. During operation of the motor, pump 101 receives oil from reservoir 102 through conduit 103, and in the brake system inactive position returns oil to reservoir 102 through conduit 104 in a closed circuit. A conventional heat sink 105 is provided within the circuit. For this purpose, a valve 106 having the characteristics of the flow regulating pump is installed at the outlet of the pump 101, and the liquid valve opens in such an inactive position of the brake system. conduit 1
Closing by actuation of the drive 107 for the valve through 08 results in the closure of the closing passages 102-103-104-102, thereby creating an overpressure in the chamber of the main pump 101 which is supplied to the brake mechanism.

As a complement to this basic structure, a second hydraulic pump 109 or, in some cases, several pumps which can also supply pressure to the brake mechanism is installed in the conduit 103, for which a valve is provided. 110 work together. The pump 109 is activated when the valve provided at its outlet is in the closed state, and the valve 110 closes the closed circuit. On the other hand, in the open position of valves 106 and 110, fluid circulates freely through the circuit without a corresponding pump, instead of supplying pressure to the brake mechanism as in continuous operating conditions.

The bypass valve 110 consists simply of a closing piston, which is continuously held in the open position by the action of a spring or similar device and is commanded by the regulating valve 106. Both valves are therefore in direct communication via an auxiliary conduit 111, which conduit 111
transmits the overpressure present in the main valve 106 to the piston of the bypass valve 110 to close the valve.

As mentioned above, when the main valve 106 is in the open state and fluid is propelled by the pump 101 freely back into the reservoir 102, there is no pressure in said valve 106 and therefore no pressure is transmitted to the auxiliary valve 110. do not have. The valve assumes the open position by its own action, whereas when the drive 107 is actuated the main valve 106 is more or less closed and a variable pressure of the same magnitude is also generated in the valve. That pressure is transmitted to the auxiliary valve 110 to similarly partially or fully close the valve 110, the closure of which determines the corresponding pressure level of the auxiliary pump 9. In this way perfect synchronization between both pumps is achieved in response to the load on the brake mechanism. This synchronization results from the continuous equilibration of the pressures present in both pumps.

In summary, before operating the drive 107 to determine the level of closure of the main valve 106 and also to determine the level of pressure in the main pump 101, it is necessary to have a complete pressure equilibrium in the auxiliary pump or pump group 109. A simultaneous effect occurs.

The effect is generally functionally similar to that obtained by using a specific pump, but it is clear that greater brake pressure is obtained.

[Brief explanation of the drawing]

FIG. 1 is a diagrammatic side sectional view of a flow regulating valve for a hydraulic brake constructed in accordance with the objects of the present invention. FIG. 2 is a diagrammatic representation of a motor vehicle brake installation comprising the valve of FIG. 1, also constructed in accordance with the invention. 1... Cylindrical chamber, 2- Outlet, 3- Pump, 4- Population, 5... Hole, 6- Piston, 7- Seal, 9- Shaft, 10-...-
・Base, 11-...Seal, 11-...Drum. 13, 14... Room, 15- Gui'r'
7 Ram, 20--Air inlet/output pipe, 21---Axial hole, 22--Opening. 23 ・-=chamber, 101-pump, 102-one tank. 104-- Conduit, 105-- Heat radiator, 1
06-Small valve 1107... Drive device, 108...
... Conduit, 109--Pump, 110-- Side passage valve, 111-- Side conduit 1-IG, -1

Claims (1)

[Claims] 1. A flow regulating valve for hydraulic brakes, which is based on the use of a pump that is driven by the traction device of the vehicle and is always in operation, the pump communicating oil with the brake system. the oil is returned to the tank through a closed circuit, and the valve is for closing more or less the size of the outlet hole to the oil return conduit to the tank, said closure being a brake. determining the magnitude of overpressure at a pump outlet communicating with the system, characterized in that said valve is configured as a cylindrical chamber associated on one side with an open end to said pump essentially propelling oil; a fluid return hole is provided at the origin of the chamber and in a radial direction, and a piston is provided at a distance from said direction, leaving said outlet hole completely free in an inactive position;
The piston is movable in the direction of the chamber in order to more or less close the size of the hole, and the piston is integral with an axis which at its opposite end intersects tightly with the closed base of the cylindrical chamber. , the shaft passes through in the direction of the drum, an intermediate membrane or diaphragm is provided in the drum, the membrane forming two separate chambers in the drum, the shaft is integral with the membrane,
and a membrane is provided in one of the chambers formed in the drum, and a spring is provided in the other chamber, in particular the chamber containing the spring is subject to the surrounding pressure, and the chamber in which the shaft is present is used to direct air into and out of the chamber. a drive device is provided which disables the action of the spring in the inoperative position of the control system and forces the piston to remain completely out of phase with respect to the oil return hole to the supply reservoir of the pump; When acting on the drive to lower the pressure in the chamber of the drum, the spring causes the hydraulic pressure to move the piston more or less towards the closed position of the oil outlet hole according to the drop in pressure created in the chamber. Brake flow adjustment valve. 2. If necessary, a shaft connected to the piston is actuated in the drum chamber, one of the chambers is always under atmospheric pressure, and the chamber containing the spring is provided with an air inlet and outlet communicating with the corresponding drive device; 2. Flow regulating valve according to claim 1, characterized in that said chamber is capable of introducing or removing a pressing force, said pressing force counteracting the action of a spring. 3. A front end of the piston and an opposite end thereof, which are open when reaching the opposite end and are arranged toward the pump so that the fluid pressure at the pump outlet does not affect the axial movement of the piston. An axial hole is provided in communication with the closed base of the cylindrical chamber and the chamber formed between them so that the fluid pressure generated by the pump acts simultaneously and in equilibrium on the two ends of the piston; and the other pressure acting counteractingly, said piston being influenced solely by a pressing force exerted thereon by a spring present in the drum. Flow regulating valve as described in . 4. Brake equipment provided with a fluid supply tank, a corresponding heat sink, and installed on the side of a flow control valve whose circuit is controlled from a brake drive, the brake drive being partially or completely in the circuit. a pressing force that establishes an adjustable pressure in the main pump, which pressure is supplied to a brake mechanism, and in particular in the hydraulic circuit, at least another hydraulic pressure similar to that of the pump. A pump is provided, the pump being capable of supplying pressure to the braking mechanism when the hydraulic circuit is closed at the outlet of the pump, the outlet being provided with a bypass valve, the valve having a closing piston thereof. is configured such that it is always in an open position, in particular said piston is driven to a closed position by the main or regulating valve, so that both valves are communicated by an auxiliary conduit and all of them are connected by their partial or complete closure.
In the manner in which the pressure developed in the direction of the main valve can be supplied to the piston of the auxiliary or side valve, its partial or Brake equipment, resulting in complete closure. 5. Flow adjustment valve for fluid brakes and brake equipment equipped with the above-mentioned valves