WO2019122772A1

WO2019122772A1 - Electrovalve device

Info

Publication number: WO2019122772A1
Application number: PCT/FR2018/053494
Authority: WO
Inventors: Sylvain Hugel; Didier CHAN; François Fischer
Original assignee: Jtekt Hpi
Priority date: 2017-12-21
Filing date: 2018-12-20
Publication date: 2019-06-27
Also published as: FR3075915B1; FR3075915A1; EP3728916A1

Abstract

The invention relates to an electrovalve device designed to be mounted between a source of hydraulic power such as a pump, and a receiver hydraulic actuator, of the type comprising a valve body (30) which comprises a first port (8) for connection to the source and a second port (7) for connection to the actuator and means that can be moved in the valve body between a position in which a flow passage (8, 7) between these ports is open and a position in which this passage is closed. The device is characterized in that it comprises a third position in which there is fluidic communication between the two ports (7, 8) via a passage (60) of which the bore section for passing the flow is reduced so as to ensure slow emptying of the receiver actuator. The invention can be used in the field of motor vehicles.

Description

ELECTROVALVE DEVICE

The invention relates to a solenoid valve device adapted to be mounted between a hydraulic power source such as a pump and a hydraulic receiver cylinder, of the type comprising a valve body which comprises a first connection port at the source and a second connection port to the cylinder and means movable in the valve body between an open position and a closed position of such a passage between the two orifices. The invention also relates to systems comprising a solenoid valve device mounted between a hydraulic power source and a hydraulic receiver cylinder.

It is known to use solenoid valves of this type, as a valve Open or close all / nothing in automatic clutch control systems applicable to transport vehicles. The receiving cylinder controls in such a system the clutch and the source is normally a pump unit.

In the clutch actuation, there are two states, namely the clutch closed and the clutch open. Figures 1 to 3 show an example of clutch actuation system respectively in the closed state and in the open state. In these figures, references 1, 2, 3 and 4 respectively denote a start / stop valve, a pump unit, a receiver cylinder and the clutch. The reference

5 denotes the hydraulic fluid reservoir and the reference

6 a throttling forming a pressure drop. The orifices on the electropump and cylinder side are referenced respectively 8 and 7. It is noted that in the closed clutch state, the valve is in its open position, and there is a hydraulic fluid flow passage between its two orifices 7 and 8, with the electric pump. shutdown. Figures 2 and 3 show the clutch in the open state. In Figure 2, the valve is open, that is to say there is fluid communication between the orifices 7 and 8, and the pump is running and maintains in the working chamber of the cylinder a high pressure. compression of the return spring. In Figure 3, the valve is closed. There is no fluid communication between the ports 7 and 8 and the pump is stopped. It is important to avoid closing the clutch too quickly and thus stalling the engine, caused by too fast emptying of the working chamber of the cylinder through the valve, whatever the operating situations encountered. In the normal mode of the automatic controller, its proper operation guarantees this condition. But, in cases of failure, for example, related to mechanical problems, control logic or power failure of the valve, closing the clutch could not be braked properly and the timing of the engine could happen.

The invention aims to provide a solution to this problem.

To achieve this object, the invention provides a solenoid valve device which is characterized in that it comprises a third position in which there is fluid communication between the two orifices, but the flow section is reduced so to ensure a slow emptying of the working chamber of the receiving cylinder.

The invention will be better understood, and other purposes, features, details and advantages thereof will become more apparent in the following explanatory description made with reference to the accompanying drawings given solely by way of example illustrating a single embodiment of the invention and in which:

FIGS. 1 to 3 are functional block diagrams of an automatic control system for a clutch, comprising a conventional open / close All or nothing valve;

FIG. 4 is a simplified schematic view of an automatic clutch control system of FIGS. 1 to 3, but including an open / closed All or nothing valve according to the invention, provided with an intermediate position;

- Figure 5 is a schematic view similar to Figure 4, but illustrates the structure of the valve according to the invention in an axial sectional view, in the open position.

- Figure 6 is an axial sectional view of the valve according to the invention of Figure 5, but shows it in the closed position.

FIG. 7A is an axial sectional view of the valve according to the invention of FIG. 5, but shows it in the intermediate mode of failure mode, and

FIG. 7B is a detail view illustrating on a larger scale the portion circled in FIG. 7A.

The solenoid valve device according to the invention has three positions, that is to say comprising in addition to the two conventional positions of opening and closing of the valve a third slow flow position through the valve through a reduced flow cross-section passage will be described hereinafter in a system comprising, as a source of hydraulic power, a feed pump for hydraulic fluid under pressure from a hydraulic cylinder, for which a slow emptying of the working chamber of the cylinder is required when the pump is inoperative. The automatic clutch control system according to Figures 1 to 3 is an advantageous but not exclusive application of the solenoid valve device according to the invention.

In Figures 4 to 7, the solenoid valve device hereinafter valve, for simplicity, is designated by the reference 10 and shown mounted between an electropump and a hydraulic receiver receiver noted respectively 2 and 3 as in the figures 1 to 3.

The valve 10 comprises a hydraulic arrangement 12 and an electrical control arrangement 14. The latter comprises a solenoid envelope 16 enclosing a solenoid 18, a magnetic core 20, axially movable in the solenoid to actuate the hydraulic arrangement by means of a solenoid. intermediate of a pusher 22 extending coaxially from the lower end of the core in the hydraulic arrangement 12.

This arrangement comprises a base 24 of generally cylindrical closed form on the side of the electrical arrangement. Its central portion is pierced with an opening 28 for passage of the pusher 22. The base is open at its opposite end and accommodates the valve body 30. This is fixedly mounted in the open end portion of the base axially protruding outwards. In this body 30, is mounted a valve 32, axially movable between a position in which it bears on a sealing seat 33 on the inner wall of the valve body, near the free open outer end thereof. and a seat release position. The latter is formed by an annular internal narrowing of the wall of the body 30 which is open at its free end to form the orifice 8 of the valve, intended to be connected to the pump 2. The tubular wall of the body 30 is pierced at the valve 32 by two diametrically opposed holes. These holes form the orifices 7 of the valve intended to be connected to the receiving cylinder 3. In its position resting on the seat, in accordance with FIG. 6, the valve prevents any communication between the orifices 7 and 8. In its release position of the seat, these orifices can communicate through an annular space 37 then existing between the seat 33 and the edge 38 of the radial closure wall 40 of the lower end of the valve. The end wall 40 is axially pierced in its center with a through hole 42 which constitutes the sealing seat of the tip 44 of a needle 46 which is arranged coaxially in the base and the valve movably between a closing position of the hole 42 being engaged in it by its tip and a position in which the tip 44 of the needle 46 releases the hole and thus allows a fluid passage between the orifice 8 of the valve body and the inside the flapper. This interior communicates with the orifices 7 on the receiving cylinder 3 side by a channel 48 allowing the pressure balance between the outer face and the inner face of the valve body. The inner end 49 of the needle, opposite the tip is in abutment against the free end wall 50 of the pusher. The end 49 has a groove 52 accommodating a snap ring 53. The snap ring 53 serves as a support for the upper end of a coil spring 54 whose other end and bears against the inner end face of the body of valve 30. The stiffness of this spring is adjusted so that starting from the closed position, it is first relatively back the needle in the valve, then allows the retreat of the valve from a value selected pressure differential (some bar). Inside the flap on the electric side, a ring stop 56 limits the relative stroke between the valve and the needle. The valve body 30 also has a passage 57 for balancing the pressure and putting the inner zone of the valve 55 under pressure from the outside. As indicated above, either the needle is pressed against the bottom of the valve to close the fluid passage hole 42, or it is raised by a stroke defined by the position of the stop ring to create a limited passage formed by the clearance between the hole and the tip 44 of the needle.

Regarding the operation of the valve according to the invention, it is already apparent from the description which has just been made. Figure 5 shows the valve in the open position. Solenoid 18 is disabled. As the spring 54 relaxes, the needle 46 is raised which drives the valve 32 through the stop ring. The pressure in the orifice 8 exerted on the outer face 40 of the valve forces it to move further back, which creates the passage space 37 of the fluid from the orifice 8 to the orifice 7, a important section, for example, of the order of 10 mm ² . The deactivated valve is thus completely running, the pump can send fluid under pressure to the receiving cylinder 3 and fill it.

[0012] Figure 6 shows the valve in the closed position. The closure is achieved by activation of the solenoid, which causes the core 20 to first push the needle 46 downwards so that its tip 44 closes the hole 42 in the bottom of the valve. The passage between the needle and the valve is thus closed. Continuing its course, the core also drives the valve on its seat 33, which causes the closure of the passage 37 between the valve and the valve body. The orifices 8 and 7 are no longer in communication and the fluid passage becomes impossible. If the closure the valve intervenes after the filling of the receiving cylinder, the pressures P7 and P8 to the orifices 7 and 8 are balanced and the closing force and maintaining the closure can be reduced.

Figures 7A and 7B show the valve in its intermediate position, namely in fault mode following for example a failure related to a mechanical problem, control logic or power failure. In this situation, it is necessary to ensure a slow emptying of the receiver cylinder, which allows to obtain in a clutch automatic control system a slow closure of the clutch. It should be noted that initially, the valve was closed in accordance with Figure 6. The pressure P7 on the side of the cylinder being greater than the pressure P8 pump side, there was the risk of a full opening of the valve and a quick emptying of the cylinder. This situation is avoided in the case of the invention by the establishment of the default mode, that is to say by the positioning of the valve in its intermediate position which is characterized by the reduction of the flow section of the fluid between holes 7 and 8.

According to the invention, by deactivating the solenoid, it causes the lifting of the needle alone under the effect of the spring 54, while the residual pressure P7 at the port 7 cylinder side, which is greater than the pressure P8 to the port 8 on the pump side, keeps the valve resting on its sealing seat 33 of the valve body 30. Figure 7B illustrates the situation thus created. The passage section between the orifice 8 and the orifice 7 is limited to the clearance 60 around the tip 44 of the needle, this game causes a loss of pressure limiting the fluid flow and thus slowing the emptying of the receiving cylinder. The passage section can be, by example, a hundred times lower than the section of the total opening of the valve. It is easily adjustable by the choice of the geometry, for example the diameter of passage in the valve, the shape of the needle, the relative displacement of the needle and the valve limited by the stop ring 56. Below a certain level of differential pressure between the orifices 7 and 8 above which the valve remains closed on its seat due to the differences in surface area under pressure, the spring raises the valve and allow communication between the orifices by the passage section 37 .

It appears from the description of the invention, given only by way of example, not limiting, that the design of the valve allows including a direct acting control, a simplification of its structure and a reduction in the number of components while limiting the energy required for its closure and maintenance in closing. It also makes it possible to obtain a large opening section to limit the pressure drop at the fluid flow in the open position.

Of course, the needle and the valve can be replaced by other elements provided that they work and cooperate to create a slow flow passage with reduced section, without departing from the scope of the invention. .

Claims

1. Solenoid valve device adapted to be mounted between a hydraulic power source (2) such as a pump, and a receiving cylinder (3), of the type comprising a valve body (30) which comprises a first orifice (8) of connection to the source and a second port (7) for connection to the cylinder and a valve (32) movable in the valve body between an open position of a flow passage (8, 7) between these two ports and a closing position of this passage, a member (46) movably mounted in the valve (32) between a closed position and an open position of a fluid passage of a reduced flow section between said first and second orifice (8, 7) through the valve, the solenoid valve device comprising an electrical arrangement (14) for controlling the displacement of the above-mentioned member (46) in the direction of firstly closing the fluid passage at reduced flow section (60) and then the displacement of the valve (32 ) in its closed position of the first orifice (8), against the return spring means, when activated, these biasing means being adapted to cause the displacement of the member (46) to its position for opening the reduced section passage (60) when the valve is in its closed position of the flow passage (37) and the fluid pressure (P7) in the second port (7) is greater than the fluid pressure (P8) in the first port (8) to hold the valve in its closed position and when the electrical arrangement is disabled, characterized in that the spring means is formed by a single spring (54) which is mounted between the the member (46) and the valve body (30) so that movement of the member towards its open position occurs under the effect of this single spring and in that a stop (56) is provided which limits the displacement stroke in the opening direction of the member (46).

2. Solenoid valve device according to claim 2, characterized in that the aforementioned member (46) is produced under in the bottom (40) of the valve (32), which is open towards the orifice (8) on the source side, and forms a punch for opening and closing a through-hole (42); internal space of the valve is in communication with the orifice (7) cylinder side, and in that the flow passage formed when the needle is in its open position is the passage of reduced section (60).

3. Solenoid valve device according to one of claims 2 or 3, characterized in that the displacement of the member (46) in the valve (32) between its closed position and the opening of the passage through the valve is limited by an abutment element (56) integral with the valve, such as a stop ring.

4. Solenoid valve device according to claim 3, characterized in that the electrical arrangement (14) comprises a magnetic core (20) movable in a solenoid (18) for controlling the displacement of the aforementioned member (46).

5. Solenoid valve device according to one of claims 1 to 4, characterized in that the opening of the valve (33) is obtained by deactivating the electrical arrangement (14) and by generating a pressure (P8) the source side is greater than the pressure (P7) on the cylinder side, and in that the needle (46) is lifted by the return spring (54) which expands and drives the valve (32) by the stop element (56) .

6. System comprising a solenoid valve device mounted between a hydraulic power source and a hydraulic receiver cylinder, characterized in that it comprises a solenoid valve device (10) according to one of claims 1 to 5.

7. Automatic clutch control system, in particular of a motor vehicle, of the type comprising a hydraulic power source and a hydraulic receiver receiver of the hydraulic fluid supplied by the source, for the control of the clutch, characterized in that it comprises a solenoid valve device (10) according to one of claims 1 to 5.