FR2507705A1 - MANUAL CONTROL VALVE FOR HYDRAULIC DRIVE SYSTEM - Google Patents

Abstract

THE INVENTION RELATES TO A MANUAL CONTROL VALVE FOR A HYDRAULIC DRIVE APPARATUS. IN THIS VALVE INCLUDING A SUPPLY DUCT AND A CONTROL DUCT, IN WHICH THE FLOW PRESSURE DEPENDS ON THE POSITION OF A CONTROL PISTON 18, THE LATTER IS MADE IN THE FORM OF A FLOATING PISTON LOADED ON ITS TWO SIDES BY THE PRESSURE AND ITS POSITION DEPENDS ON A VALVE 32 RELIEVING THE PRESSURE ON ONE FACE OF THE PISTON AND OF WHICH A SEALING SURFACE IS LOCATED ON THIS PISTON, WHILE ITS OTHER SEALING SURFACE IS LOCATED ON A REMOVABLE ADJUSTING DEVICE 31 MANUALLY. APPLICATION ESPECIALLY TO VALVES FOR OPERATING HYDRAULIC CONTROL UNITS.

Description

The invention relates to a manual control valve for a system

  hydraulic drive, which is equipped with a pressurized supply line as well as

  than a control line, the pressure or de-

  through bit depends on the position of a control piston. Such manual control valves have been known for a long time. In general, they have at least two connections, namely the connection of the supply line and the connection of the control line; in addition he is

  leakage or purge line, by which

  it is evacuated the hydraulic fluid which, passing through the control elements, has reached a zone of the valve,

  who does not participate in the order itself.

  manual placement and therefore the setting of the

  from the supply line to the control line

  is effected by means of a rotation or an axial displacement of a control piston, during the movement of which openings equipped with driving edges or control are

  brought more or less in recovery.

  Such manual control valves may be used to directly influence or even indirectly influence the downstream hydraulic drive system. In the case of direct drive, the

  manual control valve is traversed by all the power-

  which in the form of pressure and in addition to the

  flow rate, also passes through the apparatus of

  downstream hydraulic drive Due to the high power involved in some hydraulic drive systems, in the case of direct drives, very manual

  difficult to handle, the control of which

  Particularly in the case of fine dosing With respect to these controls, the indirect controls are more advantageous but they involve a servomechanism, in which the control pulses of the hydraulic auxiliary circuit passing through the manual control valve are converted into displacements of setting for the power circuit

  This increases the cost of the circuit and

  because there is no direct influence,

  the fine dosage is no longer guaranteed in many cases.

  That is why the object of the present invention is to create a manual control valve for a system

  hydraulic drive, the use of which

  days a fine and precise dosage of the power circuit, even

  in the case of very high powers.

  The present invention is characterized in that the control piston is constituted in the form of a floating piston loaded by a pressure on its two faces

  and that the position of the control piston depends on a

  poppet for relieving pressure on one face of the piston and whose sealing surface is located on the control piston and whose other sealing surface is arranged

  on an adjuster moved manually.

  In the case of the invention, therefore, the direct displacement of the control piston is avoided, but there remains almost a direct contact between the control piston on the one hand and the manually displaced adjustment member. one side of the control piston by means of a valve, it always establishes, after an adjustment operation, between the two sealing surfaces of the valve, a state of equilibrium which can

  be designated as stationary without further movement

  This means that the sealing surfaces of the valve, that is to say the control piston on one side and the manual adjustment member on the other side, are, in this stationary state, at the same spacing regardless of

  their respective position Just after a settlement operation

  ge, it therefore appears automatically a situation

  which corresponds to that of a regulator connected to the piston

  control tone, at a predetermined distance from the latter.

  It can therefore be established that from the point of view of the path of travel, the control piston and the control member

  are mutually coupled in an almost immuta-

  ble, while the displacement force is applied essen-

  hydraulically, and that it is only during this brief period of time that this almost fixed position of the control piston relative to the regulating member is eliminated. In this way, even in the case of very high power high, it is possible to carry out sensitive and precise controls, the sensitivity being due

  weak forces to be applied while the

  This decision is linked to the coupling of the control piston to

the adjustment member.

  It is particularly advantageous to make the piston in the form of a stepped or stepped piston, the pressure discharged by the valve acting on the surface of the piston, which has the largest diameter. particularly fast response, which is very advantageous for a convenient and fast control Both sides of the piston can be subjected

  at the same pressure, on the assumption that the

  the souplape is powered by a lower flow rate.

  This can be achieved very easily thanks to the

  possible throttling in the con-

  corresponding power supply.

  For a particularly fine dosage, it is recommended

  the valve for discharging in the form of a conical or needle valve, and the adjusting member is then approximately in the form of a needle. The control piston and the needle are arranged coaxially one to the other so that equilibrium can be established at the control piston as a result of a

  removal, of a different magnitude, of the sealing surface

  conical tee located on the plunger relative to the sharpened needle with a conical tip By adjusting the cone opening angle, it is possible to increase the sensitivity The lower the opening angle the more the cone approaches the shape of a cylinder, the more

  displacement is sensitive and certainly less

  adjustments needed to trigger a process

adjustment are important.

  For the transmission of the discharge rate flowing through the valve, it is possible to provide a central channel in the piston. At the free end of which a connection with a return duct is disinoised, it is advisable to communicate

  the control line with this connection, when the

  The control tone is in the zero position, so that the control line is always filled and possible shocks can be avoided in this case.

of a sudden command.

  With the manual control valve according to the in-

  it is certainly possible to carry out the direct load, or via the throttle, of the control piston by means of a respective connection with

  the supply line and therefore it is not

  A special circuit is needed to obtain the floating position of the control piston.

  for the safe return to the initial state during important races.

  carrying cases, it may be appropriate for the

  face of the piston, loaded directly or supported

  The length of the spring can be selected so that the spring is only actuated by means of a spring

  in the case of major strokes of adjustment displacement.

  To further increase sensitivity, you can connect

  derives from the manually displaced adjusting member, for example in the form of a setting needle, a lever transmission which provides a setting movement of the adjusting member, of reduced length relative to the stroke

actual adjustment.

  Other features and advantages of the pre-

  invention will emerge from the description given below.

  after, taken in reference to the accompanying drawing which shows a cross-sectional view of an exemplary embodiment

  of the manual control valve according to the invention.

  In the figure, there is shown partially, in schematic form, a manual control valve according to

  to the invention, without any accessories This valve is con-

  The hole 2 is closed on one side by a solid plug 3 and on the other side by a plug 4 through which is traversed along its length by a bore 2 of constant diameter. of the bore 2 is essentially filled by two sleeves 10 and 11 having

  different diameters as well as a guide sleeve

  The two sleeves 10 and 11 are abutting

  by their frontal faces at the characteristically

  With two arrows directed towards each other Between the right sleeve 11 and the adjacent guide sleeve 14 is still disposed a plate 12 which limits a pressure space for a control piston 18 mounted so that it can be moved in the two sleeves 10 and 11; the corresponding limit on the other side of the piston of

  control 18 is formed by the solid plug 3.

  In the lower part of the box 1 is

  a supply line which is fed from the left side and from which three

  supply connections V 1, V 2 and V 3; between the

  V 2 and V 3 supply chokes is inserted a variable throttle, with which it is possible to limit the flow of hydraulic fluid into the supply connection V 3 From the supply connection V 3, the hydraulic fluid passes into an annular space located outside the sleeve 11, where it arrives via transverse bores 20 on one of the faces of the control piston 18 In the initial position shown, the flow of fluid reduced by the throat reaches, without significant establishment of pressure, a channel 24 and through a transverse bore located at the end of this channel, in a recess 26, where the amount of fluid in a return pipe R 1 When passing through the central channel 24, the fluid passes through a conical or needle valve 32,

  the details of which will be explained below.

  Through the supply connection 1, the hydraulic fluid subjected to the pressure prevailing in the supply line arrives on the left side of the control piston 18, which is additionally charged with additional charge.

  by a spring 21 To maintain the clarity of the repre-

  tation, the spring 21 is drawn simply in the form of a phantom line, and instead of a helical spring Its length is chosen so that,

  in the null position represented, he then does not

  force or only a very small force on the control piston 18 Only in the case of a large displacement of the control piston to the left, that the

  spring 21 exerts an increasing action.

  Approximately in the middle of the casing 1 is located the supply connection V 2, through which the controlled flow rate of the fluid circulates in the case of a control

  and leaves the manual control valve according to the invention.

  by means of a control line S It circulates along a path through an annular space

  disposed outside the sleeve 11 and circulates in a

  ring space which consists of a

  trecie 34 formed inside the control piston 18.

  In the represented null position, there is no

  for this annular space formed by the narrowed portion 34, which results in the fact that no amount of

  fluid reaches the control line S under pressure.

  Only a small quantity of fluid placed at a very low pressure flows through the control line S and which reaches via the transverse bore 25 formed in the control piston 28 and

  through a corresponding channel in the man-

  This has the effect that the control line is always filled, with the result that when an order is made, an immediate reaction is obtained since the control line is already filled, and

  can also appear no shock.

  The conical valve 32 consists on the one hand

  by the conical seat formed inside the piston of com-

  18 and on the other hand by a polished surface located on the front end of a control needle 31.

  the last is the manual adjustment

  axial cement on a more or less

  the movement of the control piston 18 Once

  dump the free slot inside the conical valve 32,

  there is a tight closure so that the quantity

  of fluid subsequently arriving via the supply connection V 3 causes an increase in

  the pressure on the right side of the control piston 18.

  The control piston 18 in the form of a stepped or stepped piston has at this point a larger surface than at the location facing the plug 3, so that the control piston 18 moves towards the left until the slot opening again in the conical valve 32 causes again on this face a pressure drop which leads to an equilibrium position of the control piston 18 and therefore its

  set to rest state This state is certainly obtained only

  when the control needle 31 is maintained

  stopped and does not follow the movement of the control piston.

  of 18 moving to the left In the case of such displacement tracking, the control piston moves

  to the left until he comes to contact, for example,

  by its left side the plug 3.

  The displacement of the control piston 18 to the left causes the leading edge of the narrowed portion 34 to deviate from the plane of the sleeves 10 and abutting and reaches the space below the control duct.

  At this point the connection is established between the

  supply cord V 2 and the control line S, and the position of the front edge of the narrowed portion 34 by

  compared to the control line S is a measure of the

  If, for example, a particular drive flow

  Intense intensity must leave the control line S, the control needle 31 is first depressed until the conical valve 32 is sealed, and the control needle is then allowed to follow the piston.

  command 18 moving Depending on the setting of the choke

  upstream of the supply connection 3, this displacement and consequently the monitoring carried out by the control needle 31 is carried out slowly or rapidly, a slow displacement to be preferred rather for a gentle control action As soon as the needle order 31 has taken its position

  desired, the follow-up move is stopped, with the result that

  sequence that the control piston continues to move only a very short distance until inside the conical valve 32 is again established a state of equilibrium which can maintain the piston of

  control 18 in this position when no other

  control is exerted on the control hand 31.

  The removal of the control needle 31 from

  of the respective control position causes an opening

  complete the conical valve 32 As a result,

  is canceled on this face of the control piston 18, so that the pressure acting on the other face of the piston

  18 takes over and moves the pistol again.

  control tone to the right When the

  Mande 31 is completely retracted, the control piston 18 returns to its zero position; however, if the control needle 31 is only partially retracted, the control piston 18 is applied to the control needle 31 until the continuous sealing of the conical valve 32 has again succeeded, on this face of the piston

  18, an increase in pressure which

  holds the piston in a floating equilibrium position.

  Any leakage, which at the level of the control needle

  of 31, has escaped inside the guide sleeve 14, can escape from there through the return fitting R 2 A inside the guide sleeve 14

  there is sufficient space to accommodate a resident

  This is necessary when the mechanism engaging the free end of the control needle 31 does not contain any device for returning to the initial state or when the needle of

  control 31 is subjected to a direct manual load.

  The manual control valve according to the invention

  can be used both for a

  only for an indirect order.

  indirect control is in principle necessary in view of the sensitive and precise dosing capacity, it is however exceptionally possible to

  indirect control when, for example, the driving

  your power supply for the required power must be

  large and misshapen to the point that the capacity

  General quotient of manipulation of the control valve

manual suffers.

Claims (8)

  1 Manual control valve for a system   hydraulic drive comprising a feed pipe   pressurized arrangement and a control line, in which the pressure or the flow rate depends on the position of a control piston, characterized in that the control piston (18) is in the form of a floating piston charged on both sides by a pressure, that the position of the control piston (18) depends on a valve (32) for discharging the pressure on one face of the piston and a sealing surface of which is located on the piston of control (18) and whose other sealing surface is arranged on an adjusting member (31) moved manually.   2 manual control valve according to the claim   1, characterized in that the control piston (18) is in the form of a stepped piston and that the pressure discharged by the valve (32) acts on the surface   piston having the largest diameter.   3 Manual control valve according to any one   than claims 1 and 2, characterized in that the   two faces of the control piston (18) are loaded by the same pressure and a throttling in the supply line leading to the piston face is provided discharged by the valve (32).   4 Manual control valve according to any one   than claims 1 to 3, characterized in that the   valve is realized in the form of a conical valve   (32), a sealing surface of which is located in the pis-   control tone and whose other sealing surface is   located on the end of an adjusting needle (31).   A manual control valve according to claim 4, characterized in that the control piston (18) is provided with a central channel (24), at one end of which is located a sealing surface of the valve (32) and on the other end of which is located a link (25, he   26) resulting in a return pipe (R 1).   6 Manual control valve according to the claim   5, characterized in that when the control piston   of (18) is in its zero position, the control line (S) is in communication with the link (25,26) of the channel   (24) with the return line (R).   7 Manual control valve according to any one   claims 3 to 6, characterized in that the   direct charge, or carried out through the foreign   of the control piston (18) is obtained by means of a respective connection with the supply line (V 2).   8 Manual control valve according to the claim   7, characterized in that the directly loaded face of the control piston (18) is additionally charged by a spring (21).   9 Manual control valve according to any one   claims 5 to 8, characterized in that the   connection of the channel (24) with the return line (R 1) is   formed by a transverse bore (25) and by a   operation (26) in the control piston (18).   Manual control valve according to any one   claims 1 to 9, characterized in that   the manually displaced adjusting member (31) is connected   a lever transmission which makes a setting displacement of the adjusting member (31) of an amplitude   lower than the actual adjustment stroke.