JPS5818521B2 - Jidou Heiroben - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The invention comprises a main pump, a reserve pump, a consumer and a connection to the pressure medium tank, and two pressure spaces adjacent to both end faces of the valve pinneton, in which for hydraulic installations, especially for motor vehicles, in which one side is connected to a connection for the main pump, and in the other pressure space there is arranged a pressure spring for returning the valve pinuton to its neutral position. Related to automatic closing valves.

One of the purposes of this type of valve is to ensure the reliable functioning of hydraulic systems, in particular the hydraulic steering system of motor vehicles, under various operating conditions.

An automatic closing valve that switches the backup pump to the hydraulic pressure consumption section when the main pump's delivery flow rate is exhausted or when the pressure in the communication line between the main pump and the closing valve drops below a certain value. is publicly known.

In hydraulic systems of this type, it is possible for the main pump delivery flow to stop, for example due to insufficient belt tension in the main pump drive during use.

If the working pressure when the pump's delivery function stops is greater than the switching pressure of the closing valve, the pressure at the time of stopping remains in the valve, so the known closing valve will not operate due to the residual pressure. In some cases, it was not possible to quickly switch the reserve pump into a neutral position in communication with the consumer.

In a motor vehicle, there is a risk that if the pressure medium pump loses its delivery flow, it will no longer be possible to steer the vehicle.

The object of the invention is to maintain the supply of pressure medium to a hydraulic system, in particular to an automatic hydraulic steering system, in all operating conditions, regardless of the working pressure, and in particular even when the main pump delivery flow rate drops below a certain value. There is an automatic closing valve that allows the supply.

This object is achieved according to the invention by arranging between two pressure spaces a device for generating a pressure difference between them, and between the compression space containing the compression spring and the consuming part. This is achieved by providing a connecting pipe.

. Hereinafter, embodiments of the present invention will be explained in detail with reference to the drawings.

The illustrated closing valve essentially consists of a housing 1 and a valve piston 3 inserted axially displaceably into a bore 2 of the housing 1 .

This valve piston 3, together with the borehole 2 of the housing 1, forms two pressure spaces 4 and 5 on its two end faces, one of which is connected to a connection 6 for the main pump 7, and the other. The pressure space 5 is connected to a hydraulic pressure consumer 8 via a connecting line 9 .

A compression spring 10 is arranged in the pressure space 5 and serves to return the valve piston 3 to its neutral position.

The casing 1 has a connection 11 for the reserve pump 12, a connection 13 for the consumer 8 and a connection 14 for the pressure oil tank 15.
The connecting portion 13 , 14 has two control grooves 16 formed with a predetermined width on the inner circumferential side of the perforation 2 of the casing 1 .
and 17.

The valve pinuton 3 is provided with an axial bore 19 opening into the pressure space 4, and two grooves 2 having a predetermined width.
0,21 are provided, and the groove 20 is radially perforated 1.
8 into the axial bore 19 , and the groove 21 in all positions of the valve pinneton 3 into the connection 11 for the auxiliary pump 12 .

Also, grooves 20 and 16. Grooves 21 and 16. grooves 21 and 1
Valve piston 3 by respective mutually adjacent corners of 7
The control edge A1. is opened and closed as the control edge A1. B1. C1
are formed respectively.

When the valve pinuton 3 is in the neutral position shown in FIG. 1, the control edges A, C1 are closed and the control edges B1 are open.

As the valve pinuton 3 moves to the left, the edge C1 first
opens, then B.

is closed, and A1 is further opened.

The first valve pinuton 3 is adjusted by a compression spring 10.
In the neutral position shown in the figure, the control edge B1 is opened.
The reserve pump 12 is communicated with the consumption part 8 via the second check valve 24.

When the main pump 7 is operated, first of all, if the delivery flow rate of the main pump 7 is small, the entire delivery flow passes through the throttle hole 22, the first check valve 23, and the connecting pipe 9 toward the consumption part 8. flows.

As the delivery flow rate increases, the pressure drop in the throttle bore 22 increases.

When the pressure difference occurring between the pressure space 4 or the axial bore 19 and the pressure space 5 reaches the value of the quotient of the force of the compression spring 10 divided by the cross-sectional area of the valve piston 3, the valve pinuton 3 is moved by the compression spring 10. is displaced toward the left against the force of

This displacement of the valve pinuton 3 first opens the control edge C1 and then the control edge B.

closes.

Thus, only when a connection is established from the reserve pump 12 to the pressure medium tank 15 is the communication from the reserve pump 12 to the consumer 8 broken.

Therefore, the connection 11 of the reserve pump 12 is always connected to the groove 2.
1, and the groove 21 is always in communication with either the groove 16 or 17, so that the liquid delivered from the reserve pump 12 is not confined in a closed room, and the groove 21 is opened to the reserve pump 1.
The pressure of the pump No. 2 does not rise to an abnormal pressure higher than the set pressure of the pressure limiting valve provided inside the pump.

This button ensures the safety of the pump 12 and also prevents heating of the pressure medium.

If the valve histone 3 is further displaced, the control edge A1 opens only after the closure of the control edge B1.

When the control edge A1 is closed, pressure medium cannot enter the pressure medium tank 15 from the connection 6 of the main pump 7 via the control edges Al s B 1 and C1, but when the control edge A1 is opened, Immediately, main pump 7
The amount of output is divided.

This branching makes it possible to ensure that only the main delivery flow portion required to correctly maintain the pressure difference necessary for moving the valve piston 3 flows through the throttle bore 22 towards the consumer 8 .

Even if the delivery flow rate increases due to kneading, the throttle hole 22
The pressure loss caused by this will be kept to a minimum.

The minimum value of the pressure loss can be determined by the size of the orifice 22 of the throttle 9, depending on the delivery flow rate of the main pump 7 required to move the valve piston 3 against the force of the compression spring 10.

In the position of the valve pinneton 3 at this minimum delivery flow rate, both adjacent corners of the grooves 17 and 21 are placed exactly at the same position, and at this time, the control edge C1 is in a closed state on the verge of opening. , has neither underlap nor overlap.

That is, when the delivery flow rate increases above the minimum delivery flow rate, the control edge C1 does not open immediately, and when it decreases, C1 is immediately closed.

In addition, at the time of this minimum delivery flow rate, the control edge B1
is open, and the control edge A1 is in a closed state.

Then, when the delivery flow rate of the main pump 7 is reduced below the minimum value determined by the restrictor bore 22 at any operating pressure, the closing valve is closed by closing the control edge C1 and opening the control edge B. Spare pump 12
is connected to the consumption part 8.

At relatively low working pressures, the closing valve is frequently activated when the delivery flow rate of the main pump 7 can fall below a minimum value.

In the Σ structure shown in FIG. 1, the main pump T is always in communication with the consumption part 8 via the throttle bore 22.
The main pump 7 is not separated from the consumer 8 in any position of the valve piston 3 unless the reserve pump 12 is still in communication with the consumer 8 .

Therefore, during frequent closing operations of the valve pinuton 3, frequent no-pressure conditions do not occur in the consumer, even for a short time, as in known closed-circuit valves.

In addition, when the delivery flow rate of the pump 7 decreases and the valve pinneton 3 is about to be returned by the compression spring 10, both pressure spaces 4 and 5 are not communicated through the relatively large throttle hole 22. , pressure empty.

The pressure medium remaining in the gap 4 can flow into the pressure space 5 through the borehole 22 .

Thereby, the valve pinuton 3 can be moved easily and in a short time, and the switching operation can be carried out very quickly regardless of the residual pressure.

FIG. 2 shows another embodiment of the closing valve according to the invention.

The first check valve, which prevents a short circuit between the reserve pump 112 and the pressure medium tank 115 in the event of a failure of the main pump 107, has been replaced by an additional control edge D2.

In this case, the throttle bore 122 is connected to both pressure spaces 104.
, 105, but creates a communication between the pressure space 104, which is in communication with the main pump 107, and an annular groove 25 arranged on the valve piston 103.

This annular groove 25 together with a further control groove 26 arranged in the housing 101 forms a control edge D2.

In this embodiment of the closing valve, both control edges C2 and D2 are also connected in order to obtain short switching times.
are positioned so that they are simultaneously opened and closed as the valve pinuton 3 moves.

As a result, in the return process of the valve pinuton 103 to the neutral position by the compression spring 110, the control edges C2 and D2 remain open until the control edge B2 opens, and as a result, the return process of the valve piston 103 is quickly performed. It will be done.

In this case, the slowing of the switching process only begins when control edge B2 is opened and reserve pump 112 is connected to consumer 108 via control edge B2.

- By suitably arranging the control edges B2 and A2 in relation to the control edges C2 and D2, one of the two pumps 107' or 112 is always connected to the consumer 108;

In addition to the above-mentioned major advantages obtained by the present invention,
The advantage of the closed-circuit valve constructed according to the invention is that a reliable supply of pressure medium to the consumer is guaranteed without pressure-free periods and without impairing leakage losses in all operating conditions.

Embodiments according to the present invention are summarized below.

1) A self-closing valve according to the claims, in which the device for generating a pressure difference consists of a restrictor bore 22 arranged in the valve piston 3.

2) The automatic closing valve according to the claims and item 1), wherein the check valve 3 is disposed between the pressure space 5 containing the compression spring 10 and the consumption part 8.

3) 2 where the throttle hole 22 is adjacent to the end face side of the ascending piston 3
The automatic closing valve according to item 1), which is configured to be a direct communication hole between the two pressure spaces 4 and 5.

4) The throttle bore 122 connects the connection 1 to the main pump 107
06 and the annular groove 25 disposed in the valve pinuton 103.

[Brief explanation of the drawing]

1 and 2 show longitudinal sections through two embodiments of a self-closing valve according to the invention. 1,101...Casing, 2...Perforation, 3,10
3... Valve pinuton, 4, 5, 104, 105... Pressure space, 6. IL 13, 14, 106...Connection part, 7゜107...Main pump, 8,108...Consumption part, 10゜110...Compression spring, 12,112...Spare pump, 15 .115...pressure medium tank, 16,
17.26... Control groove, 18... Radial drilling,
19... Axial drilling, 20,2L 25... Annular groove, 22,122... Diaphragm drilling, A1. B1. C1,
A2. B2. C2, B2... control edge, 23, 24
···non-return valve.

Claims (1)

[Claims] 1. Two pressure spaces adjacent to both end faces of the main pump, the reserve pump, the connection space for the hydraulic pressure consumption part and the pressure medium tank, and the valve piston, one of the pressure spaces being In self-closing valves of hydraulic steering systems for motor vehicles, which are connected to a connection for the main pump and in which a compression spring is arranged in the other pressure space for returning the valve piston to its neutral position; two pressures A device for generating a pressure difference between the pressure spaces 4 and 5 is arranged between the spaces 4 and 5, and a pressure space 5 in which the compression fan 10 is arranged.
and the consuming part 8 (a connecting pipe 9 is provided. At the same time, in the neutral position of the valve pinuton 3 when the delivery flow rate of the main pump 7 decreases, the connecting part 11 of the reserve pump 12 and the consuming part 8 and the main pump 7.
Annular grooves 20, 21 of a predetermined width and control grooves 16, 17, which cut off the connecting flow path and connect the connection part 11 to the connection part 14 of the pressure medium tank 15 when the delivery flow rate increases, and control grooves 16, 17, respectively, are connected to the valve piston 3. The valve piston 3 is formed in the casing 1 that houses the valve piston 3, and is connected to the main pump 7 when the valve piston 3 is closed by the inner circumferential surface of the casing 1 in the neutral position and the delivery flow rate of the main pump 1 rises above a predetermined value. A self-closing valve characterized in that a radial perforation 18 is formed in the valve pinneton 3 to connect the pressure space 4 and the connection part 13.