Sharp R-267LST Manual do Utilizador descarregar pdf (Página 9)

4,309,917

1

TRANSMISSION

AND

CONTROL

SYSTEM

The

invention

hereindescribed

was

made

in

the

course

of

work

performed

under

a

contract

or

subcon

tract

thereunder

with

the

United

States

Department

of

the

Army.

FIELD

OF

INVENTION

This

invention

relates

to

transmissions

and

controls

therefor and,

particularly,

cross

drive

hydromechanical

transmissions

and

controls

therefor.

RELATED

APPLICATIONS

Commonly

assigned

US.

Patent

Applications

Ser.

NO.

051,109

now

US.

Pat.

No.

4,258,548

in

the

names

of

Arthur

Hall

III

and

Warren

E.

Leet;

and

Ser.

No.

051,110

now

US

Pat.

No.

4,244,279

in

the

names

of

Max

E.

Stewart

and

James

R.

Lucas,

filed

concurrently

on

June

22,

1979,

are

related

applications.

BACKGROUND

OF

INVENTION

A

related

cross

drive

transmission

and

controls

there

for

are

shown

in

US.

Pat.

No.

3,611,838

Robert

C.

Utter,

granted

Oct.

12,

1971.

A

related

hydromechani

cal

transmission

is

shown

in

U.S.

Pat.

No.

3,982,448

James

C.

Polak

and

Phillip

J.

Ross,

granted

Sept.

28,

1976.

Related

hydrostatic

transmissions

and

units

thereof

are

shown

in

US.

Pat.

Nos.

3,274,946

Edw.

E.

Simmons,

granted

Sept.

27,

1966

and

3,752,010

R.

G.

Tipping,

granted

Aug.

l4,

1973.

The

type of

modulator

valve

used

is

shown

in

US.

Pat.

No.

3,093,010

W.

M.

Spreitzer

et

al.,

granted

June

1

l,

1963.

Speed

governors,

as

shown

in

US.

Pat.

No.

2,762,384

Rosenberger,

granted

Sept.

11,

1956,

are

used.

A

related

ratio

gover

nor

is

shown

in

US

Pat.

No.

3,583,154

Robt. C.

Utter,

granted

June

8,

1971.

Manual

electric

controls are

shown

in

US.

Pat.

No.

3,640,157

Robt.

H.

Schaefer,

granted

Feb.

8,

1972.

A

related

zero

stroke

bias

valve

is

shown

in

US.

Pat.

No.

3,590,577

Robt.

C.

Utter,

granted

July

6,

1971.

SUMMARY

OF

INVENTION

The

cross

drive

transmission

has

a

hydromechanical

propulsion

drive

and

a hydrostatic

steer

drive,

both

being

driven

by

an

input

drive

and

driving

right

and

left

differential

output

drives

for

straight

propulsion

drive

and

differential

steer

drive.

The

hydromechanical

pro

pulsion

drive

is

a

multispeed

(preferably

with

three

ratio

ranges)

hydromechanical,

synchronous

shifting

trans

mission

providing

continuously

variable

ratio

change.

The

steer

drive

is

a

continuously

variable

ratio

transmis

sion,

such

as

a hydrostatic

transmission.

The

input

drive

barrel

and

the

output

drive

barrel,

both

of

which

dis

place

a

small

volume

of

?uid,

are

located

in

the

bottom

of

the

housing.

The

hydromechanical

propulsion

trans

mission

and

hydrostatic

steer

transmission

barrel

is

lo

cated

above

these

input

and

output

barrels

so the

sump

in

the

bottom

of

the

housing

has

a

large

?uid

capacity

volume

at

low

?uid

levels.

This

control

system

is

designed

for

use

with

a

propul

sion

hydromechanical

transmission

in

which

the

motor

of

the

hydrostaticportion

of

the

drive

provides

driving

torque

during

one

drive

ratio

and

reaction

torque

dur

ing

another

drive

ratio,

and

wherein

its

shifts

from

one

ratio

to

another

are

designed

to

be

synchronized.

The

hydraulic

ratio

of

this

transmission

is

controlled

by

varying

the

displacement

of

a

variable

displacement

20

25

30

40

60

2

pump

and

motor.

In

synchronous

shifting

hydrorne

chanical

transmissions,

the

gearing

is

designed

so

that

the

engaging

friction

members

of

the

oncoming

friction

device

for

establishing

2nd

and

higher

ratio

ranges

have

slightly

different

rotational

speeds

before

and

after

the

shift

to

accommodate

the

exchange

of

efficiencies

in

the

hydrostatic

drive

by

a small

change

of

motor

speed

for

improved

synchronization.

The

manual

control,

on

a

shift

from

neutral

to

pivot

steer

or

forward

and

reverse

drive

positions,

controls a

disconnect valve

to

establish

disconnect

clutch

drive

to

the

propulsion

and

steer

drives

and

to

make

the

steer

controls

operational.

The

manual

control,

on

a

shift

from

neutral

or

pivot

steer

to

forward

or

reverse

drive

positions,

controls the

neutral

valve

to also

connect

the

advance

signal

so

both

the

advance

and

return

signals

are

connected

to

the

propulsion

hydrostatic

control,

and

supplies

the

shift

valves

so

both

the

propulsion

hydrostatic

and

ratio

shift

controls

are

operational.

Also,

the

forward

and

reverse

valves,

in

forward and

reverse

manual

positions,

respectively

provide

forward

and

reverse

signals.

In

forward

and

reverse

drive,

in

1st

ratio,

the

return

signal

is

connected‘

to a

return

signal

valve

and

a

zero

stroke

bias

valve

to

the

actuator,

and

the

advance

signal

is

connected

by

the

advance

signal

valve

to

the

actuator

for

changing

pump

and

motor

displacement.

In

2nd and

3rd

ratio,

the

return

signal

is

connected

by

the

return

signal

valve

to

the

advance

signal

control

valve

which

supplies

both

return

and

advance

signals

to

the

actuator

for

changing

both

pump

and

motor

displacement.

The

advance

signal

control

valve

reverses

the

connections

in

2nd

and

reverse

ratio

range

to

provide

reversed

displacement

change

relative

to

input

speed.

To

accomplish

the

above

shift

requirement,

a

motoroperated

shift

signal

valve

has

a

spool

operatively

connected

for

movement

with

the

displacement

mem

ber

of

the

hydrostatic

motor

to

provide

a

1-2-1

shift

signal

at

the

desired

motor

displacement

for

1-2-1

shift

ing.

A

similar

pump-operated

shift

signal

valve provides

a

2-3-2

shift

signal

at

the

desired

pump

displacement

for

2-3-2

shifting.

These

1-2-1

and

2-3-2

shift

signals

are

connected

by

a

ratio

shift

signal

valve

in

upshift

or

downshift

positions

respectively

in

response

to

the

ad

vance

or

return

signal

to

provide

1-2

and

2-3

upshifts

and

2-l

and

3-2

downshift

signals

to

control

shift

valves

to

effect

such

shifts.

The

shift

valves

lock

in

upshift

position

until

a

downshift

signal

effects

a

downshift.

A

plurality

of

exhaust

trip

valves

are

associated

with

the

shift

valves,

providing

a

restricted

exhaust

and

re

stricted

supply

to

maintain

the

off-going

friction

device

pressurized

until

the

oncoming

friction

device

has

suffi

cient

engagement

pressure

to

carry

the

torque

and

to

discontinue

the

restricted

supply.

A

ratio

governor

is

responsive

to

input

speed,

com

pares

input

speed

to

a

varied

desired

set

speed,

and

operates

as

a

regulator

to

provide

equal

low

pressure

advance

and

return

signals

on

a

speed

match,

to

quickly

increase

the

advance

signal

to

maximum

value

and

re

duce

the return

signal

to

zero

on

overspeed,

and

to

quickly

increase

the

return

signal

and

reduce

the

ad

vance

signal

to

zero

on

underspeed,

to

control

pump

and

motor

displacement

to

maintain

input

speed

at

the

set

speed.

These

signals

are

distributed

by

the

control

system

to

an

actuator

which

controls

the

movement

of

servo

valves

and

hydraulic

servos

to

control

the

dis

placement

member

of

the

hydraulic

pump

and

motor.

The

ratio

governor

signals

are

supplied

to

the

ratio

shift

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