JPS5821074A - Hydraulic device conducting electrical proportional control - 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 involves a type of electrical proportional control comprising a hydraulic servo valve having a pilot chamber and a hydraulic pilot valve for regulating the pressure in the pilot chamber of the hydraulic servo valve. Related to hydraulic equipment.

In particular, one invention relates to a hydraulic device of the type described above.

In this, the pilot valve is electromagnetically operated and includes a duct connected to a source of pressurized fluid through an orifice of small cross-section and communicating with the pilot chamber, a hole intended to be connected to a discharge tank, and a hole intended to be connected to the discharge tank. a body having a passage communicating the duct; a shutter cooperating with a seat formed in the body corresponding to the passage; an armature and a first winding coupled to the body of the pilot valve; An electromagnet having a movable core which faces the seat and urges the shutter into its closed position with a force proportional to the strength of the supplied current.

Pilot valves of the above-mentioned type have various applications in different types of equipment, such as, for example, presses, machine tools, machine processing machines, plants in the iron industry, processing machines for plastic materials, and in general: We have found all applications where it is desirable to regulate the pressure in a hydraulic circuit.

The stretch allows the pressure in the pilot chamber of the servo valve to be changed proportionally by changing the current supplied to the electromagnet windings. Therefore.

The variation in current causes a proportional variation in the force that biases the shutter against its seat and controls intermediate communication between the aging duct and the discharge tank.

However, this type of valve produced to date has a relatively complex structure, is expensive, heavy and bulky and is used particularly in the automotive industry, for example in brake systems.

It has the disadvantage of being poorly adapted for use in transmission and engine feed systems.

The aim of the invention is to provide a hydraulic device with electrical proportional control that makes it possible to overcome the above-mentioned disadvantages.

In view of this object, the present invention is characterized in that a seat cooperating with the shutter is located in the area of the pilot valve body in the armature of the electromagnet, and the shutter is directly actuated by the movable core of the electromagnet. A hydraulic device of the above type is provided.

The present invention allows the valve to be made of simpler construction with fewer parts, and the # valve is more economical, less bulky, and lighter than valves of this type made to date. In the known valve, the seat cooperating with the shutter controlling the communication with the discharge tank is located in the region of the body of the pilot valve outside the armature of the electromagnet, and the shutter cooperating with the wrinkle seat is located on the movable core. indirectly controlled by the movable core of the electromagnet through an element interposed axially between and the shutter.

Joy 1 of the hydraulic device of the present invention! l! In an embodiment, a small cross-section orifice connecting the duct to the source of pressurized fluid is formed in the body of the pilot valve. however.

In a second embodiment, an orifice is formed in the hydraulic servo valve in such a region that a pilot chamber is interposed between the orifice and the duct.

A preferred embodiment of the hydraulic device of the present invention further has the following features. The movable core of the electromagnet is slidable within the support main of the winding, and the pilot valve body is in the form of a cylindrical element inserted into one end of the support bobbin of the winding. # This end of the valve body part, together with the end of the movable core facing it, defines a main chamber in the support ffry, and said duct formed in the pilot valve body part defines a main chamber in the support ffry; The passageway opening into the chamber and connecting the duct to the exhaust hole is comprised of a main chamber and at least one auxiliary duct connecting the main chamber to the exhaust hole, and the shutter dust is removed from the main chamber. Consists of the end of the duct that opens.

Preferably, the portion of the valve body centrally exiting the electromagnet is inserted into the seat of the body of the hydraulic thermistor valve such that the ser provides a coupling between the valve and the pilot valve. This allows the pilot valve body to perform different functions at the same time. The stretcher body actually acts both as a rest for the valve itself (in which the duct and the seat of the shutter are formed) and as an element connecting to the servovalve. Moreover, the pilot valve body part is preferably made of ferromagnetic material and therefore.

Upon excitation of the winding, it also serves to attract the moving core of the electromagnet to itself.

Further features and advantages of the valve of the invention will become clear from the following description, given by way of non-limiting example only and with reference to the accompanying drawings, in which: FIG.

In FIG. 1, the reference numeral 1 designates the body of a hydraulic servovalve with 1 cylindrical bore 2, and part of the body 3 of the pilot valve is designated by #
It is slidable within the via 2. The body part 3 has a cylindrical shape,
Made of ferromagnetic material. The pilot valve is a tubular fie
It further comprises an electromagnet 4 having a winding 5 supported by a ring 6. The pin 6, although of non-ferromagnetic material, is located within an armature 7 of ferromagnetic material having a cup-shaped element 8, which element 8 has a bottom wall 8a and a plate 9 with a central hole at its open end. It is prepared in the department. The annular plate 10, on the one hand.

Between the end of the bobbin 6 and the bottom 8a, on the other hand, the bobbin 6
is inserted between the end of the plate 9 and the plate 9. a cup-shaped element 8;
Both plates 9, 10 are made of ferromagnetic material.

The ferromagnetic core 12 is slidably clamped into the winding support tubular bobbin 6 by intercalation of the sleeve 11 of non-ferromagnetic material.

The end of the pilot valve body 3 opposite the end inserted into the bore 2 of the valve body has a plate 9, a plate 10 and a sleeve 11.
protrudes through adjacent ends of and is located within them.

The body 3 of the pilot valve has an axial through duct 18 communicating at one end with a pilot chamber 14 via an orifice 13, the pressure in the chamber 14 being regulated by the pilot valve. Pore 18 is.

The isthmus hole 21 communicates with a radial hole 21 formed in one body through a restricted orifice 23 of limited axial length.
It communicates with a port 22 formed in the valve body 1 and intended to be coupled to a source of pressurized fluid.

The body 3 has a peripheral groove that confines the II-shaped chamber 16 within the well 2 . The body part 3 also has a discharge hole 15 which communicates through a port 17KII-shaped chamber 16 of the body part 1 which is connected to a discharge tank (not shown).

The body portion 3 further includes a flow path connecting the duct 18 and the discharge hole 15. t* flow path is pilot chamber 1
Main chamber 1 where the end of the duct 18 opposite 40 opens
9 (confined within the sleep 11 at opposite ends of the body 3 and the movable core 12) and at least one auxiliary duct 20 connecting the cough main chamber 19 to the exhaust hole 151C.

The body 3 is sealed to the I72 by a series of annular seal rings 240 interposed in respective peripheral grooves formed in the body 3.
installed inside. The body part 3 is fixed to the body part 1 with screws 2T, and is attached around the outside of the body part 1 for installation of a bracket 26 which is arranged to fix the body part 3 of the pilot valve to the body part 1 of the therme valve. It further has a groove 25.

A sealing push 28 is attached to the end of the duct 18 that opens into the main chamber 19, and the inner end hoe of the scissor push facing the chamber 19Vc limits the ball shutter 290 seat, and the #shutter is the 1st winding 5 When energized, the movable core 12 of the electromagnet is biased against the seat.

The plug 30 is force fit at the end of the sleeve 11 opposite the body part 3. The plug 30 has a peripheral groove in which a retaining ring 31 is placed, which contacts a spacer ring 32 .

The plug 30 defines an auxiliary chamber 33 within the sleep 11 with the end of the movable core 12 facing it. The auxiliary chamber 33 communicates with the main chamber 19 via a series of axial peripheral grooves 34 (only one shown) formed in the movable core 12. The core 12 also has a small diameter intermediate portion that defines an annular chamber 35 . According to the structure described above), in operation, a thin film of fluid enters the chamber 3.
5 to act as a bearing and facilitate the sliding of the core 12 within the sleeve 11.

The body of the movable core 12 has an axial through hole into which the pin 36 is press-fitted. The bottle 36 has both ends projecting from the body of the core 12 . The portion of the tongue 16 that protrudes from the end of the core 12 toward the chamber 33 is
and to prevent these surfaces from coming into contact with each other with the risk of hydraulic "sticking" of the opposing surfaces of the plug 30. The bottle 36 is made of a non-ferromagnetic material and has a hardness that is even higher than that of the movable core 12.

At the end of the tank 6 which projects from the body of the movable core 12 towards the main chamber 19, the core 12 has a cavity 37 in which a pole shutter 29 is accommodated.

At the opposite ends of the plug 30 and the movable core 120 there is installed a helical spring 38, the operation of which will become clear below.

The orifice 13 is formed in a restriction plate 39 located at the end of the duct 18 that opens into the pilot chamber 14 .

The orifice 13 prevents fluctuations in the transmitted pressure between the duct 18 and the chamber 14.

The movable member of the servo valve 1) (not shown) I/C fixed element is designated by the reference numeral 40. The element 4o is subject to the pressure of the chamber 14 and therefore the pressure fluctuations with and ! ! Causes a change in the position of element 0. Also.

In FIG. 1, the port 41 of the inlet hole of the servo valve is shown;
The port 41 is communicated with an outlet port (not shown) K via a flow path controlled by the movable member of the servo valve.

The operation of the hydraulic system shown in FIG. 1 is first order.

The position of the element 40 fixed to the movable member of the valve depends on the pressure in the pilot chamber 14. Port 22 of valve body 1 and pilot valve body 3
and the restricting orifice 23 of the hole 21 formed in the /cut 1
8 to the pilot chamber 14.

The seat shutter 29 is pressed against its seat by the movable core 12 of the electromagnet 4 when the winding 5 is energized. Duct 18
If the pressure of
and an auxiliary duct 20 to communicate the duct 18 with the hole 15 connected to the discharge tank. Therefore, the pressure in the duct 18 (and therefore the pressure in the pilot chamber 14) is.

It depends on the value of the force applied to the shutter 29 by the movable core 12.

Adjustment of the pressure in the pilot chamber 14 (which causes a variation in the position of the movable member of the servo valve) is carried out in a proportional manner by changing the strength of the current applied to one winding 5.

In the above configuration, in particular, the seat of the pole shutter 29 is connected to the electromagnet 4.
0 is formed in the region of the body of the pilot valve located in the winding 5, and a scissor shutter is provided for the movement of the electromagnet without any intervening elements; 'The result is a valve that is simpler, more economical, and less bulky than conventional electrical proportional control pilot valves.

FIG. 2 (in which parts common to FIG. 1 are designated with the same reference numerals) shows that in the case of a small cross-section orifice communicating the duct 18 with a source of pressurized fluid, the pilot valve A second embodiment of the present invention differs from that shown in FIG. 1 only in that the K-cer is formed on the movable member 40 of the valve.
An example is shown.

Moreover, in this case the restriction orifice 13 is.

Omitted.

At 49, a small cross-section orifice (designated 42) is formed in the wall of the movable member 40 in an area such that the pilot chamber 14 is interposed between the orifice 42 and the duct 18. The orifice 42 communicates with a bow 43 of the body 1 of the servo valve which is intended to be coupled to a source of pressurized fluid.

The operation of the valve shown in FIG. 2 is exactly the same as that described above with reference to the valve of FIG.

l! shown in Figure 1! Theoretical analysis of the operation of the hydraulic device according to the invention in the example shows the unambiguous relationship between the strength of the current supplied to one winding 5 and the pressure in the duct 18 (for each value of the current (to which only one value of the pressure must correspond) and the stability of the device and allows the identification of criteria for dimensioning the pilot valve.

The following parameters can be identified.

P - the supply pressure of the pilot valve (at the inlet funnel 22), Q - the ideal maximum flow rate of the pilot valve (the ideal condition is the density of the fluid that occurs when the pressure in 718 is zero);

IIimaw -'ma-here K P',,, is the maximum design pressure corresponding to the duct 18, ``min = 'min/Pko\KP'. 1o is the minimum design pressure corresponding to the duct 18. Ah 夛.

Current value corresponding to ``P'mhx'' (spring 38
), the inner radius of the sleeve 11.

Thickness of the wall of the upper sleeve 11, W# Thickness of the thick plate 10 of the cocoa-facing armature, Thickness of the bottom wall 8a), here! , and D are the diameter of the hole of the pusher 28 and the diameter of the pole shutter 29, respectively.

The value of the next coefficient is found by * experiment.

Dispersion coefficient of the see electromagnet.

μL permeability in air.

Og=Flow coefficient of narrow section 23.

Q. It is better to keep the values of the above-mentioned parameters constant regarding the flow rate of the passage controlled by the s-shutter 29.

The dimensions of the values of the following properties are finite:

D=d, /Fπ 4JQ・Maximum distance) JK and H are the number of turns of the electromagnet's winding.

This last relationship determines the value of the product of the three dimensions, and then selects any two values of these dimensions and calculates the third value.
It is always possible to determine the value of .

Here, h is the distance between the movable core of the electromagnet and the body 3 of the valve when the shutter 29 is pressed against its seat.

Of course, for this last relationship, it is necessary to choose the values of t,v in such a way as to make it possible to obtain a non-negative value of h.

Last I/c.

and \, -1n is the value of the current corresponding to %"min I/c.

In fact, taking into account processing tolerances, a larger electromagnet (as defined by the above relationship) may be used to allow greater flexibility in the use of the pilot valve when supply pressures higher than the design pressure occur. It is convenient to use the maximum stroke IO value of the moving core. ``Adoption of a value larger than the theoretical value of the maximum stroke obtain.

Solving this problem by increasing the strength of the current supplied to the windings is a mistake in that it leads to a sharp increase in pressure in the duct 18 with fluctuations.

The action of the helical spring 38 interposed between the plug 30 and the movable core 12 is exactly what solves the # problem. The spring has a sufficient load to balance the minimum pressure present in the duct 18 when the distance between the movable core 12 and the body 3 of the valve is at its maximum.

Therefore, when there is a minimum design pressure in the duct 18, this pressure is perfectly balanced by the mosquito spring and the strength of the current supplied by the electromagnet winding mK is almost zero.

Moreover, the use of spring 38 ensures shorter response times and increases the stability of the device. Body part 3.

It may also be made of non-ferromagnetic material. However, in this case it is essential that the movable core 12 is not located in a central position within the winding 5 when pressing the shutter 29 towards its seat.

An example of the dimensions of a pilot valve according to the embodiment shown in reverse FIG. 1 is given below.

Design data P -200NW/crn" Q mouth 20cy'/sec p w 9.10-' 111 seconds"/at'I! ! mi
n −0,02 11j,,! -〇・99 R■0.7 am t sgo, 1cII W Catfish 0.3 "max dew 1 ampere J -0,8 Value deduced by experiment μ x 1.26 ・10' 1iW/(ampere x number of turns )2v = 1.3 0 -0.78 O, -, 0,55 o' -0,66 The magnitude of the following characteristic is obtained.

eLg-0,07cII d8-0.2 bacteria.

D ””o-5scst 1 shows the actual pressure/current characteristics of this embodiment with the values shown in FIG.

Of course, the details of the construction of a practical embodiment of the invention are as follows.

Although shown and described by way of example only, a wide range of modifications may be made without departing from the scope of the invention.

[Brief explanation of drawings]

FIG. 1 is a partial cross-sectional view of a first embodiment of the hydraulic device of the present invention. FIG. 2 is a partial cross-sectional view of a second embodiment of the hydraulic device of the present invention. 1 shows a diagram of the pressure/current characteristics of a practical example of a pilot valve forming part of the inventive device; FIG. 1... Body of servo valve 2... Cylindrical bore of body 3... Body of pilot valve 4... Electromagnet 5...
Volume * 6... Tubular zone 7... Armature 11... Sleep 12... Movable core 14... Pilot chamber 15... Discharge hole 18... Duct 19... Main chamber 20 ... Auxiliary duct 23 ... Restriction orifice 29 ... Hall shutter 30 ... Plug
33... Auxiliary/auxiliary chamber 34... Axial peripheral groove 35... Annular chamber 36... Zen
38...Helical spring 39...Restriction plate 42...Orice agent with small cross section Asamura Kogai 4 people F-ie, i

Claims (1)

[Claims] (1) *Pressure-? To adjust the pressure in the pilot chamber of the valve (pilot chamber (14)), #pilot valve #pilot chamber (14) is equipped with a hydraulic pressure valve that competes with the #pilot chamber (14). )k connected to the pressurized fluid 1 through the oriice (23, 42) of small cross section.
1 [K duct to be combined) (18), # hole (15) to be combined with the discharge tank, and # discharge hole (Is) K1m duct) (1
8) and passages (19, 20) communicating with each other.
3) and the scissor body l5 (3) corresponding to the # passage (19, 20).
) K, the shutter (29) cooperates with the seat formed, and the armature (7) to which the pilot valve body (3) K is attached.
), the winding (5), and the scissors winding*(S) IIc, which is directed toward the seat with a force proportional to the strength of the supplied current and the shutter (29
), the seat cooperating with the shutter has a movable electromagnet (4) that biases the shutter to its closed position; #shutter (29) located in the area of the pilot valve body (3) in the armature (7) of (4);
is directly operated by the movable core (12) of the electromagnet (4). (2) An orifice (23) of small cross-section connecting the duct (1) to a source of pressurized fluid is formed in the body (3) K of the pilot valve. Hydraulic device as described in section. (3) A small cross-section orifice (42) is formed in the hydraulic surge valve that connects the duct (1B) with the pressurized fluid INK, and the pilot chamber (14) connects the duct (1B) with the pressurized fluid INK. Hydraulic device according to claim 1, characterized in that it is interposed between the orifice (42) of small cross section. (4) Small cross-section orifice (23, 42). Hydraulic device according to claim 1, characterized in that it has a relatively short axial length. (5) The movable core (12) of the front electromagnet (4) is slidably mounted on the tubular support bone (6) K of the winding (5), and the pilot valve body (3) is It is in the form of a cylindrical element and has one end inserted into one end of the support bone (6) of the winding (5) of the electromagnet (4) and the valve body (3).
) is connected to the main chamber (1) in the support M-gen (6).
9) with the end of about 1 movable core (12) facing thereto, said duct (18) formed by said pilot valve body part (3) K opening into said main chamber, #duct) ( 1
8) to the discharge hole (15), the passageway connects the main chamber (19) and the main chamber (19) to the discharge hole (15).
5) K-coupled at least one auxiliary duct) (2G), and the seat of the shutter (29) is constituted by the end of the main chamber (19) K-opening scissor duct) (18); Claim 1!1IK1. l[The hydraulic device described. (6) The hydraulic device according to claim 1111, wherein the pilot valve body portion (3) is made of a ferromagnetic material. (7) The movable core (12) sleeps (11)
By interpolating the support bobbin (6) of said volume III (5)
6. A hydraulic device according to claim 5, wherein the hydraulic device is slidably mounted within the hydraulic device. (8) 1Ift valve body (3)K facing closing element (30) closing the end of said sleeve (11)
), a closure element (30), together with the end of said movable core (12) facing it, confines an auxiliary chamber (33) in the sleep (11), and the movable core (12) , the main chamber (19) is connected to the auxiliary chamber (33)K.
8. Hydraulic device according to claim 7, characterized in that it has a series of communicating axial peripheral grooves (34). (9) The movable core (12) has an annular peripheral chamber (3
9. Hydraulic device according to claim 8, characterized in that it has an intermediate section of small diameter which confines 5) within said sleep (11). A (trans)elastic device (38) is connected to the closure element (30);
9. The hydraulic device according to claim 8, wherein the hydraulic device is interposed between the end portion of the movable core (12) facing the skeleton. a force said closed #l! ! a stroke limiting device (36) for limiting the stroke of said movable core (12) in the direction of the element (30), the opposite ends of the wrinkled movable core (12) and the closure element (30) comprising: Claim 8, characterized in that they are separated from each other at this stroke limit position.
Hydraulic device as described in section. (2) The stroke limiting device may include the movable core (1
12. Hydraulic device according to claim 11, characterized in that it is constituted by an axial bottle (36) in which the pressure is metered. (To) The seat of the shutter (29) is
according to claim 5, characterized in that the main chamber (19)K of the main chamber (19)K is defined by an inner edge of a pusher (28) mounted at the open end of the valve body (3)K. Hydraulic equipment. α◆ The portion of the valve body (3) protruding outward from the electromagnet is scissored so as to achieve coupling between the hydraulic thermistor valve and the pilot valve. Insert into the seat (2) of the valve body (1)'
A hydraulic device according to claim 5, characterized in that: 6. Hydraulic device according to claim 5, characterized in that the duct (18) is constituted by a groove extending axially through the body (3). 0. The end of the duct (18) communicating with the pilot chamber (14) is provided with a perforated restriction so as to prevent the transmission of pressure fluctuations between the duct and the pilot chamber (14). 6. Hydraulic device according to claim 5, characterized in that it comprises a plate (39).