DE3115091A1 - Servo valve for brake power amplifier - Google Patents

Description

PATENT LAWYERS

WUESTHOFF - ν. PECHMANN - BEHRENS - GOET2

PROFESSIONAL REPRESENTATIVES BEFORE THE EUROPEAN PATENT OFPICE MANDATAIRES AGREis PRES l / oFFICE EUROPEEN DES BREVETS

KJ II \ * t \ J KJ ι

DRMNG. FRANZ TUESTHOFF

¹ DJU5HIL. FREDAVOESTHOFF (1927-1956) DIPL.-ING. GERHARD PULS (1951-1971) DIPL.-CHEM. DR. E. BARBER OF PECHUANN DR.-ING. DIETEK BEHRENS DIPL.-ING .; DIPL.-TrlRTSCH.-ING. RUPERT GOBTZ

1A-54 606 D-8000 MUNICH

SCHWEIGERSTRASSE

phone: (089) 66 20 ji telegram: frotectpatent telex: 514070

April 14, 1981

Patent application

Applicant: LUCAS INDUSTRIES LIMITED Great King Street
Birmingham 19, England

Title: Servo valve for brake booster

,.;.,; it. * - * DR-HNCFRANzvi

WUESTHOFF-v.PECHMANN-BEHRENS-GOETZ "^ ^HILPREDA '

. . ,. ,. I *, ' . * ■ ß R-HNCFILANZ VUESTHOFF

PATENT LAWYERS * - - · ■ '*.

"* ■ DRJJiILFRED

d1pl.-chem.dk, e. fkeikekk by pechmann representatives before the burofean patent office dr.-ing. Dieter Behrens

MANDATAIRES AGREES PRES L'oFFICE BUKOPEBN DBS BREVETS DIPL ₁ -ING ^ DIPU-VIRTSCH ₁ -ING ₁ RUPBRTGOETz

D-8000 MUNICH 90 1A-54 606 SCHWEIGERSTRASSEZ

phone: (085) 66 ίο 51 telegram u: pkotectfatbnt telex: 1 * 4070

description

Servo valve for brake booster

The invention relates to a method for adjusting the distance between a section of an elastic reaction disk and a valve control member in a booster for a vehicle brake system and relates in particular to performing this adjustment on a booster with a valve housing with a stepped bore in which a valve control member can be moved to and fro its front end can be brought into engagement with an elastic reaction disk, through which output forces an output member are transmitted, the valve control member having a first circular ring-shaped at its rear end Has valve seat which is coaxial with a second circular valve seat on the valve housing, also with a valve closure member which can be brought into engagement with the valve seats and one connected to the valve control member Drive rod.

With such force amplifiers, it is important to coordinate the various dimensions so that when both valve

/ 2

seats are covered by the valve closure member, between the front end surface of the valve control member and a support surface there is a predetermined axial distance for the radially outer portion of the rear surface of the reaction disk. the The size of this distance determines the so-called entry point, this is the amount by which the output or output force of the power amplifier increases with the input force unchanged must before the reaction disk transmits a substantial response to the valve control member. The boost ratio is thus increased during the equalization of the above-mentioned distance, by an excess of force to overcome static friction to create.

Since the distance is determined by several dimensions, it is usually necessary to have a close tolerance for each of these dimensions. This increases the manufacturing costs.

The inventive method for adjusting the axial distance between the front surface of the valve control member and a support surface for the radially outer portion of the rear surface of the reaction disk in a booster of the The type described at the beginning consists in that before the assembly of the reaction disk and the valve closure member with the valve housing a first contact member is arranged near the front surface of the valve control member, a second contact member is arranged near the valve seats, the first contact member having a first contact surface can be placed against the front surface of the valve control member and with a second contact surface on the support surface and the second contact member with a third contact surface with the first valve seat and with a fourth contact surface the second valve seat can be brought into engagement, the two contact members are moved against each other and at least one Section of the valve is permanently shifted so that when the movement is completed, all four contact surfaces on their Abut counterparts, the axial relative positions of the first and second as well as the third and fourth contact

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surface are chosen so that in the assembled state the desired axial distance through said displacement of the one valve section will have been set in advance.

The permanent displacement of the valve section is preferably produced by plastic deformation of this section.

The plastic deformation is preferably performed by an ultrasonic device generated, which expediently has an ultrasonic vibrator for one of the contact members. the However, deformation can also be caused in other ways, for example by using a heating coil.

A third and fourth contact surface is preferably used flat surface used on the second contact member, as a second contact surface a circular surface on the first contact member and as the first contact surface, the end surface of an approach projecting coaxially from the first contact member. The length of the approach determines the said axial distance in the assembled booster.

A corresponding surface on a sleeve made of plastic, which is the front end, is usually used as a support surface of the valve control member encloses. Preferably, the sleeve is used as the part that is plastically deformed, wherein the axial length of the sleeve is reduced by the plastic deformation.

The material displaced during the plastic deformation of the sleeve is preferably received in at least one recess, which is initially formed on the sleeve or on the adjacent portion of the valve housing.

Instead of or in addition to deforming a sleeve, at least one of the valve seats can be provided with the second contact member

- "* - '54

be deformed. If only one of the valve seats is to be deformed, this seat is designed so that initially, before the deformation, protrudes axially backwards beyond the other valve seat.

Embodiments of the invention are explained in more detail below with reference to schematic drawings. It shows:

1 shows a longitudinal section through part of a conventional brake booster with an illustration the arrangement of the reaction disk and the valve control member, the latter drawn in the position in which both valve seats are covered,

2 shows a similar view when an ultrasonic probe is used to deform one of the valve seats according to a first method according to the invention,

3 shows the application of a second method according to the invention, in which the sleeve of the one shown in FIG Booster is deformed, and

4 shows a modified method according to the invention for deforming the sleeve.

According to FIG. 1, a cylindrical valve control member 1 is guided displaceably in a section 2 of reduced diameter of a stepped bore 3 of a valve housing 4 designed as a plastic molding. An elastic reaction disk 5 rests at its front end on a head of an output member 7, which is designed as an output rod in the example shown, whereas an annular section 8 of its rear surface rests on the front surface 9 ^{1 of} a valve part, designed as a sleeve 9 in the example shown and fixed in the valve housing 4 so as to be immovable is present. The front ^{surface 9 1} forms a support surface for the reaction disk 5. The rear end of the valve control member 1 has a first valve seat 10 and the valve housing 4 has a second valve seat 11 coaxial with it. In the covered position shown

/ 5

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is a flat circular ring-shaped on both valve seats 10 and 11 Surface 12 of a valve closure member 13. The distance X between the radially outer portion of the front surface 14 of the valve control member 1 and the adjacent surface 15 of the reaction disk 5 is according to the method set according to the invention. The distance X also represents the axial distance between the front surface 9 ′ of the sleeve 9 and the front surface 14 of the valve control member 1.

According to FIG. 2, a first cylindrical contact member 16 has a flat axial projection 17 of a length equal to that Desired distance X. The contact member 16 is arranged so that a second contact surface forming a circular ring Surface 20 rests against it on the front surface 9 ″ of the sleeve 9.

A second contact member 18 in the form of an ultrasonic welding probe of cylindrical shape with a flat end surface 19 is introduced upwards in such a way that the end surface 19 rests against the lowest of the valve seats 10 and 11 and deformed it until both valve seats 10 and 11 are coplanar, the top of the valve control member 1 on the the end surface 21 of the projection 17 forming the first contact surface is applied. The distance X is for the covered state of the assembled booster has been determined. In this case, the flat end surface 19 forms both the third and also the fourth contact surface.

The first contact member 16 could have a flat or undivided end surface and the second contact member 18 could with be provided with an end face with a shoulder; but it could also both contact members 16 and 18 end faces with approach provided that each configuration is used the axial distance between the first and the third contact surface by the desired amount X from the axial distance differs between the second and the fourth contact surface.

- € - 54 606

The valve shown in Fig. 3 is essentially the same as that shown in Figs. 1 and 2, except that the Valve housing 4 has an annular recess 22 opposite the radially outer wall 23 of the sleeve 9. In this Case is the method to set the first contact member 16 by ultrasound in vibration while it itself and the second contact member 18 are moved against each other, whereby the sleeve 9 made of plastic is plastically deformed in order to reduce its length until the desired Distance X is reached. When the sleeve 9 is reduced in length, the recess 22 absorbs plastically displaced material on.

According to Fig. 4, the rear end of the sleeve 9 has a plurality of circumferentially spaced radial slots 24 so that a caused by ultrasound deformation of the sleeve material between the slots 24 can take place around the Reduction of the axial length of the sleeve 9, also here by displacing the contact member 16 in ultrasonic vibrations, to enable.

In yet another method of adjusting the distance X, the sleeve 9 is designed so that it is initially sits tightly, but with respect to the valve housing 4 to the rear, according to FIGS. 3 and 4 downward, axially limited is movable. The seat can be sufficiently tight around the sleeve 9 after the contact members 16 and 18 are applied a predetermined force have been moved relative to each other to hold in the set position, or it can Aids can be provided which block the sleeve 9 in the set position. The aid can be an adhesive bond be.

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Claims (10)

• 'k *. "-." ', DIlJ-ING. FRANZ »WESTHOF * - 'PATENTANWÄLTE ...' ..-; ., ^. "IL.pREDA TOMTHO" u, 17.19j6, WUESTHOFF-v.PECHMANN-BEHRENS-GOETZ d, pl.-ing. gerhaRD puls DIPL.-CHEM. DR. E. BARON OF FECHiIANN PROFESSIONAL KEFRBSENTATIVES BEFORE THE EUROPEAN PATENT OFFICE DR.-ING. DIETER BEHRENS MANDATAIRBS AGREES PRES l'OFFICB EUROPEEN DES BREVETS DIPL1-ING ^ DIPL1-TrIRTSCH1-INCRUPERTGOETZ D-8000 MUNICH lA-54 606 SCHWEIGERSTRASSEZ phone: (089) 66 ίο j-i TELEGRAM 1. A method of adjusting the axial distance between the front surface of a valve control member and a support surface for the radially outer portion of the rear surface of a reaction disk in a booster with a valve housing with a stepped bore in which the valve control member can be moved back and forth and at its front end with the elastic reaction disk can be brought into engagement, through which output forces are transmitted to an output member be, wherein the valve control member has a first annular valve seat at its rear end, which with a second annular valve seat is coaxial on the valve housing, furthermore with one with the valve seats in engagement bringable valve closure member and a drive rod connected to the valve control member, characterized in it that before assembling the reaction disk (5) and the valve closure member (13) with the valve housing (4) a first contact member (16) is arranged near the front surface of the valve control member (l), a second contact member (18) near the valve seats (10,11) is arranged, the first contact member (16) with a first contact surface (21) on the front surface (14) of the valve control member (1) and with a second contact surface (20) can be placed against the support surface (9 ') and the second contact member (18) with a third contact surface (19) with the the first valve seat (10) and a fourth contact surface (19) can be brought into engagement with the second valve seat (11), the two contact members (16,18) are moved against each other / 2 - 2 - 54 and at least one section (sleeve 9; valve seat 10; valve seat 11) of the valve is shifted permanently so that at End of movement on all four contact surfaces (21,20,19,19) rest on their counterparts, the axial relative positions of the first and the second as well as the third and the fourth contact surface (21,20,19,19) are chosen so that the desired axial distance in the assembled state (X) will have been determined in advance by said displacement of the one valve section (9; 10; 11). 2. The method according to claim 1, characterized in that the permanent displacement "of the one Valve section (9; 10; 11) is generated by an ultrasonic device which plastically deforms this section . ..:. 3. The method according to claim 1, characterized in that g e k e η η shows that the permanent displacement of one valve section (9; 10; 11) is produced by heating the same to deform it plastically. 4. The method according to any one of claims 1 to 3, characterized in that as a belonging together Pair of contact surfaces end surfaces (20, 21) at least one of the contact members (16) and a projection (17) are used be, wherein the shoulder (17) protrudes axially from the end surface (20) of the contact member (16). 5. The method according to claim 4, characterized in that g e k e η η that both the third and fourth contact surface (19) is a flat surface of the second contact member (18) is used, the approach (17) from the end surface (20) of the first contact member (16) around one of the axial distance (X) protrudes the same amount and the end surface of the projection (17) the first contact surface (21) and the The end surface of the first contact member (16) forms the second contact surface (20). - 3 - 54 6. The method according to any one of claims 2 to 5, characterized in that the valve portion which is plastically deformable, a sleeve (9) is used which encloses the front end of the valve control member (1) and the support surface (9 ¹ ) , wherein the axial length of the sleeve (9) is reduced after the plastic deformation, 7. The method according to claim 6, characterized in that g e k e η η that the material displaced during the plastic deformation of the sleeve (9) is in an annular shape Recess (22) is received, which is formed in the radially inner wall of the valve housing (4). 8. The method according to claim 6, characterized in that g e k e η η that the reduction of the axial length of the sleeve (9) by radial slots (24) in the rear end the sleeve (9) is made possible, between which the sleeve material is plastically deformed. 9. The method according to any one of claims 1 to 5, characterized characterized in that the valve section which is permanently displaced is at least one of the valve seats (10,11) is used. 10. The method according to claim 9 in conjunction with claim 5, characterized in that the second Contact member (18) relative to the first contact member (16) is moved so that one of the valve seats (10 or 11), the initially protrudes backwards beyond the other valve seat, is shifted permanently until both valve seats (10,11) are coplanar.