Sharp R-267LST Manual de usuario descargar pdf (Pagina 13)

4,309,917

9

input

or

lst

governor

pressure

increasing

with

increas

ing

engine

speed

in

1st

or

input

governor

pressure

line

165

which

is

connected

to

the

steer

signal

valve

166

(FIG.

3D).

ADVANCE

RETURN

SIGNAL

SYSTEM

The

advance

return

signal

system 160

is

a

governing

system

and

has

ratio

governor

162

of

input

speed

gover

nor

assembly

120;

advance

cut-off

valve

122;

lst

range

advance

control

valve

123;

return

demand

valve

124;

restriction

and

check

valve

device

229;

and

rate

of

ratio

change

control

203

having

restriction

and

check

valve

devices

233

and

249,

for

supplying

advance

or

return

signals

to

advance

or

return

line

204

or

205.

RATIO

GOVERNOR

The

ratio

governor

162, as

described

below,

has

some

portions

similar

to

the

ratio

governors

shown

in

the

above

US.

Pat.

No.

3,611,838,

and

new

portions.

The

ratio

governor

162

includes

a

ratio

governor

valve

170

having

a

valve

spool

167

having

four

equal

diameter,

spaced

lands

a,

b, c,

and

d,

slidably

disposed

in

a

valve

bore

168

in

valve

body

169.

A

pair

of

fly

weights

171

of

the

flyweight

assembly

172

are

rotated

by

governor

shaft

163

so

that

an

outward

force

propor

tional

to

engine

speed

is

imposed

on

the

right

end

of

valve

spool

167.

A

spring

173

is

compressed

between

a

spring

seat

174

fixed

on

the

other

end

of

valve

spool

167

and

the

end

wall

176

of

piston

177

slidable

in

a

bore

178

of control

cylinder

179

having

an

end

wall

180.

A

cham

ber

181

in

control

cylinder

179,

between

end

wall

180

and

end

wall

176

of

piston

177,

is

continuously

con

nected

by

transfer

port

182

to

power

signal

line

183

which

supplies

a

pressure

proportional

to

engine

power

or

brake

apply

pressure.

The

higher

pressure

in

engine

power

signal

line

146

or vehicle

brake apply

signal

line

184

is

connected

by

power

signal

shuttle

valve

186

(a

known

shuttle

valve)

to

power

signal

line

183.

Control

cylinder

179

is

slidably

mounted

in

a

bore

187

in

valve

body

169.

There

is

sufficient

clearance

for

full

control

movement

of

both

piston

177

and

control

cylinder

179.

Either

or

both

throttle

cam

188 or

steer

request

cam

189

abuts the

end

wall

180

of

control

cylinder

179

to

vari

ably

position

control

cylinder

179.

Throttle

and

steer

request

cams

188

and

189

are

respectively

?xed

on

throttle

and

steer

request

shafts

191

and

192

which

are

concentrically

rotatably

mounted

on

a

support

portion

193 of

transmission

housing

38.

The

engine

throttle

194

is

connected

by

throttle

linkage

195

to

rotate

throttle

shaft

191

and

cam

188

in

proportion

to

throttle

position

or

leading

torque

demand.

The

steer

request

lever

196,

which

is

controlled

by

the

driver

to

request

steer,

is

connected

by

steer

request linkage

197

to

rotate

steer

request

shaft

192

and

earn

189

in

accordance

with

steer

request.

In

this

throttle

and

steer

request

device

190,

the

throt

tle

cam

188

or

steer

request

cam

189

moves

control

cylinder

179

which

engages

and

moves

piston

177-or

power

pressure

in

chamber

181

moves

piston

177.——s0

that

spring

173

provides

a

bias

force

on

valve

spool

167

which

is

equal

to

the highest

of

the

bias

forces

provided

in

response

to

the

control

functions,

throttle

demand,‘

steer

request,

engine

power,

or

brake

apply

pressure.

This

bias

force

determines

the

set

speed,

a

predeter

mined

variable

speed

value

in

a

range

from

engine

idle

speed

to

maximum

engine

speed,

at

which

ratio

gover

nor

162

regulates

engine

speed

by

controlling

the

pro

pulsion

drive

ratio.

20

25

35

40

45

55

65

10

In

ratio

governor

valve

170,

the

central

lands

b

and

c

of

spool

167

block

bore

168

and

have

a small

land

over

lap

relative

to

the

ports

for

advance

and

return

feed

lines

201

and

202,

while

end

lands a

and

d

of

spool

167

have

a

through-passage

or

groove

for

exhaust.

Mainline

112

is

connected

to

bore

168

between

lands

b

and

c

of

spool

167.

When

engine

speed

equals

or

matches

set

speed,

mainline

pressure

is

connected

through

the

land

overlap

to

both

advance

and

return

feed

lines

201

and

202;

and

both

lines

are

connected

through

the

overlap

respectively

through

lands a

and

d

of

spool

167

to

ex

haust,

so

both

the

advance

and

return

signal

pressures

have

low

values.

On

engine

overspeed

(engine

speed

greater

than

the

set

speed),

mainline

pressure

is

supplied

to

advance

feed

line

201

to

increase

advance

signal

pressure

to

mainline

pressure,

and

return

feed

line

202

is

exhausted

through

land

d

of

spool

167.

On

engine

un

derspeecl

(engine

speed

less

than

the

set

speed),

mainline

pressure

is

supplied

to

return feed

line

202

to

increase

return

signal

pressure

to

mainline

pressure,

and

advance

feed

line

201

is

exhausted

through

land

a

of

spool

167.

An

increased

degree

of

movement

of valve

spool

167

from

a

central

position

in

the

range

of

the

land

overlap

increases

the

rate

of

pressure

change

of

the

advance

and

return

signals.

On

movement

from

its

minimum

(idle)

to

full

(maxi

mum)

throttle

position,

engine

throttle

194

rotates

throttle

cam

188

to

act

on

and

move

control

cylinder

179

and

piston

177,

and

spring

seat

174

to

increase

the

bias

force

of

spring

173

and

to

increase

the

set

speed

of

ratio

governor

162

from

minimum

(idle)

to

maximum

set

speed—such

as

full

power

engine

speed

or

maximum

engine

speed.

On

movement

from

its

minimum

to

maximum

posi

tions,

the

null

or

straight

steer

position,

to either

right

or

left

full

or

maximum

steer

request

positions,

the

steer

request

lever

196

rotates

steer

request

cam

189

in

either

direction.

Similar

right

and

left

portions

of

steer

request

cam

189

act

similarly

to

increase

the

bias

force

of

spring

173

to

increase

the

set

speed

from

a

minimum

(idle)

to

a

high

set

speed,

e.g.,

80%

of

maximum

engine

speed.

As

set

forth

above

and

further

explained

below,

each

control

functions

at

its

minimum

value-idle

throttle

demand,

zero

steer

request,

idle

engine

power

or

com

pressor

discharge

pressure,

and

brake

disengaged

or

zero

brake

apply

pressure

operates

to

control

ratio

gov

ernor

162

to

provide

the

minimum,

or

engine

idle

set

speed.

Then,

as

the

control

functions

are

increased,

the

set

speed

is

increased

from

idle

speed

to

higher

engine

speeds.

The

set

speed

will

be

the highest

set

speed

called

for

by

any

one

of

these

control

functions

which

individ

ually

operate

independently

or,

in

the

absence

of

any

other

control

function,

as

follows.

The

power

pressure

signal

in

power

signal

line

183

is

alternatively

the

engine

power

signal

pressure

or

vehi

cle

brake apply

pressure,

and

acts

in

control

cylinder

chamber

181.

Since

control

cylinder

179

abuts

at

least

one

of

the

throttle

and

steer

request

cams

188

and

189,

there

is

a

reaction;

and

when

the

power

pressure

has

a

sufficiently

high

value

to

provide

a

higher

bias

force

on

spring

173

than

that

provided

by

throttle

and

steer

re

quest

cams

188

and

189,

the

power

pressure

moves

piston

177

to

increase

the

bias

force

of

spring

173

and

the

set

speed

from

a

minimum

to

a

maximum

set

speed.

The

minimum

set

speed

for

each

of

these

control

func

-

tions,

torque

demand,

steer

request,

engine

power

and

brake

torque

at

their

minimum

value,

is

engine

idle

speed.

Control

cylinder

179

will

be

positioned

by

the

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