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Begin OCR Text:
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B RAKE VA LVE
A brake valve is connecfed to each of the rear
wheel brake lines, se Fig. 5-6. When the ingoing
brake pressure e_ceeds 29 kp/cm2 (41 2 p.s.i.) a
reduction takes place in the valve. The more po-
werful the pedal pressure, the greater wi Il be the
reduction and thereby the larger the dífference
between the hydraulic pressure in the front wheel
and rear wheel cyl inders. This resu Its in a suitable
distribution of braking force between both pairs of
wheeIs. The construction of the b,ake va_ve is ., _
shown is fig. 5-41 and its function is the fol Iow- Pressure below 29 kpJcm_
Ing_ (4i2 p s i )
When the footbrakes are applied, the pressure from
th t _. d d h FIg. f_42. Br8ke application
e ma S ef Cy In er l S tranSmltte vja t e Conneç-
tion (7. Fig. f41 ). The pressure then proceeds
through the cyl inder (6), the counterbore, past the Fo,çe .,, çy_.,,de, (6) moves the p.,sto, t, the _eFt so
valves (1 7) and (4) to cyl inder (3) and then on that ehe ,a_,e ,od çome, ,p aga.,,st .,ts stop a,d
through connection (1 9) to the rear wheel cyIinders h _ h h _
' OpenS f e Va Ve t I S CaUSlng t e preSS Ure I n Cy In-
see fig. 5-42. The hydrau Iic pressure per un it sur- de, (3) eo .,,ç,ea,, Due to the _a,ge, p,ess,,e ,,,-
faCe is eq ual on the different parts of the piston Façe ,., eh .,s çy_., ,de, the p.,seo, .,g moved to the
(21 ). but s ince _ts pressure surface is larger in ,.,ght ,ga., , a,d ehe va_ve ç_oses _, th.,s way the
cyIinder (3) than in cylinder (6). the force developed p.,seo, asg,me, , pog.,t.,o, oF baia,çe a,d' the
wi Il move the piston to the right of the figure . F h b k _ __ b
_ O UtßOlng preSS Ure rOm t e ra e Va Ve WI e
However, th is is counteracted by the pregsu,e f,om i h h F T
OWer t an t e IngOlng preSS Ufe. See Ig. 5-42. he
the springs (1 O) d FF
' l erenCe In theSe preSS UreS IS detefm Ined by the
When the hydraul ic pressure approaches 29 kp(cm2 d.,FFe,e,t a,eas a,d sp,.,,g ee,,.,o,
C4 1 2 p.s. i.) the spri ng pressure is overcome and the whe, the b,ake peda_ .,s ,e_eaged the p,essu,e .,,
PISton (2 1 ) is moved to the right By means of pres- eh _. d (6) F _ _ Th . t i2_ ) . d
' e Cy In ef a S. e pIS On l S mOVe tO
sure from the sma l Ier spring (5). the valve (4) shuts the ,.,ghe by ,p,.,,g (_ o) whe, the p,e,,,,e o, the
off the con nection between the two cylinde,s a,d . h h d d i h ' _ (4) F _i h h
rlg t- an Sl e O t e Va Ve a S So m U C t at
forms two separate systems. one for the front the hyd,a,_ .,ç p,ess,,e o, the ieit_h,,d ,,de e,,b_es
wheels and one for the rea, whee_, h _ b d h b
' f e Va VeS tO e aCtUate , t e COnneCtjOn etWeen
With Continued increase in pressure in the master boeh ehe çy_.,,de,s ,, ope,ed ag,.,, As the p,ess,,e
cylinder and fronf wheel cyl inders. the hydraulic Fa_ _s. sp,.,,g (_ o) p,esses the _e_ p.,,to, baçk eo ._es
orig inal position where the va Ive is held in the open
position by mechanical means, see fig. 5-41 . The
equalizi ng valve (1 7) is fitted w_th control chan-
nels wh ich ensure an even flow of pressure through
the valve.
uIOO_L&V$O_
FIg. 5_gl . Brake v8lve, co_$_ucfio_
1 Plug 12 Adjusting 8crew
2 O-ring l3 Locknut
3 Cylinder t4 Sprlng hous_ng -
4. Value l5 Refa__e_
5. Value spring 16. Bolt
6 Cylinder l 7 EQuallzing valve
7 ConneCtion to l8 O ring
master cylinder 19 Connectio_ fo _ea_
8 PISton 9aSket wheel brake cyl inders _ Reduced pressure _ Pressure abDue 2g kp/cm2
g gracket 2O Houging f4l2 p S.i )
1 O Spring 2l Piston
l l. Retaincr 22 Valve houa_r._ F,_. _g_. _educ,__ gcf,on _ . 1 9
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