Caterpillar Cat E70B TRACK EXCAVATOR (Prefix 6AK) Service Repair Manual Instant Download

1
Service Repair Manual
Models E70B TRACK EXCAVATOR
2
Shutdown SIS
Previous Screen
Product EXCAVATOR Model E70B EXCAVATOR
6AK Configuration E70B TRACK-TYPE EXCAVATOR
6AK00001-UP (MACHINE) POWERED BY 4D32 ENGINE
General Service Information E70B EXCAVATOR TRAVEL
DRIVE AND MOTOR Media Number -SENR4584-00 Publicat
ion Date -01/08/1989
Date Updated -11/10/2001

• General Notes
• This machine has been designed conforming to JIS
  (Japanese Industrial Standard) requirements in
  which all measurements are based on the metric
  system. And this manual, wherever practical,
  these measurements are shown to the nearest
  fraction in feet, pound, etc., but whenever in
  doubt, the metric value shown should be used.
• Numbers indicated in ( ) in this manual are the
  part numbers given in structural and exploded
  diagrams.
• Specifications are subject to change with or
  without notice owing to improvements, that may be
  introduced after publication of this manual.
• Conversion table for metric system indications
  into Foot-pound units (U.S.A.)

Copyright 1993 - 2019 Caterpillar Inc. All
Rights Reserved. Private Network For SIS
Licensees.
Fri Aug 30 192730 UTC0800 2019
3
Shutdown SIS
Previous Screen
Product EXCAVATOR Model E70B EXCAVATOR
6AK Configuration E70B TRACK-TYPE EXCAVATOR
6AK00001-UP (MACHINE) POWERED BY 4D32 ENGINE
General Service Information E70B EXCAVATOR TRAVEL
DRIVE AND MOTOR Media Number -SENR4584-00 Publicat
ion Date -01/08/1989 Specifications
Specifications 1. General
Date Updated -11/10/2001
2. Travel motor
4
https//www.ebooklibonline.com Hello dear
friend! Thank you very much for reading. Enter
the link into your browser. The full manual is
available for immediate download. https//www.eb
ooklibonline.com
5
3. Travel gear
Model Notation Travel motor
Brake valve
6
Copyright 1993 - 2019 Caterpillar Inc. All
Rights Reserved. Private Network For SIS
Licensees.
Fri Aug 30 192818 UTC0800 2019
7
Shutdown SIS
Previous Screen
Product EXCAVATOR Model E70B EXCAVATOR
6AK Configuration E70B TRACK-TYPE EXCAVATOR
6AK00001-UP (MACHINE) POWERED BY 4D32 ENGINE
General Service Information E70B EXCAVATOR TRAVEL
DRIVE AND MOTOR Media Number -SENR4584-00 Publicat
ion Date -01/08/1989 Function And Construction
Structural Diagram
Date Updated -11/10/2001
8
(No Transcript)
9
Operating Principles
10
General Travel drive and motor (73) consists of
four components swash plate type axial plunger
motor (81), counter-balance valve (80), parking
brake (78), and reduction gears (79). Travel
drive and motor (73) converts the energy of
pressure oil supplied by the pump into rotational
force of proper speed, and transmits this force
to sprockets (74) to run the machine. When the
machine is going downhill, the travel drive and
motor prevents it from overrunning, or forces the
machine to a halt when it stops. When the
machine parks or stops on a slope, the braking
torque of the travel motor shaft prevents the
machine from moving. Travel drive and motor (73)
is mounted on lower frame (72) and is capable of
supporting the machine weight and of countering
external force acting on the track frame during
digging operation.
11
Pressure oil from the hydraulic pump enters port
(77) and flows through counter-balance valve (80)
to run motor (81) at high speed. Reduction gear
(79) reduces the high rotational speed to produce
slow and large torque which it turn rotates hub
(1) (case). The motor return oil flows through
counter-balance valve (80) and out of port (76),
and returns to the oil tank. The motor rotates
reversely when the pump pressure oil enters port
(76) and is drained from port (77). During motor
rotation, case drain oil from sliding sections
returns from port (75) to the tank. The
counter-balance valve controls the motor rotation
by controlling the oil flow into/from the motor.
Parking brake operates together with the spool of
the counter-balance valve. The parking brake is
released when the motor operates and engaged when
the motor stops. The operating principle will be
explained for each of the above four components.
12
Motor The pressure oil from the pump enters port
(77) in rear flange (27), and flows through the
brake valve section in the rear flange. It then
goes to the cylinder bores in cylinder block (3)
through kidney port (82) in timing plate (35).
Depending on the swash plate angle, kidney port
(82) in timing plate (35) allows the pressure oil
to go to only four to five cylinder bores (83)
that are situated on one side of Y1 - Y2 line
between the top and bottom dead centers of the
piston stroke.
13
The pressure oil in cylinder bores (83) of
cylinder block (30) generates force (84) to
pistons by acting on the ends of pistons (31)
(four or five). Piston force (84) then acts on
swash plate (29) through shoe (32). Swash plate
(29) is tilted to the piston, so pistons (31)
are moved down on the tilted surface of swash
plate (29) by piston force (84). As pistons move
down, cylinder block (30) rotates.
Since cylinder block (30) and shaft (28) are
directly connected with splines, shaft (28)
rotates together with cylinder block (30) which
in turn generates torque.
14
Counter-balance valve Starting and
traveling Pressure oil comes into port (77) in
rear flange (27), opens valve (52), and flows
into kidney port (82 -1) in motor timing plate
(35). From the kidney port, this oil flows into
cylinder bores (83) in cylinder block (30) to
run the motor. At the same time this pressure oil
flows through passage (88) into spool chamber
(89) from small hole (87) of spool (48), thereby
pushing spool (48) that is held in its neutral
position by spring (54) to the left. As spool
(48) is pushed leftward, it introduces passage
(85), recesses of spool, against rear flange
(27). Through passage (85) created between kidney
port (82-2) in timing plate (35) and port (76)
in rear flange (27), return oil flows back into
the tank. As spool (48) moves from its neutral
position, passage (86) to the parking brake
opens, and pressure oil flows into the cylinder
chamber of the parking brake. This releases the
parking brake force and allows the motor to run.
15
When pressure oil flows to port (76) in rear
flange (27) and is drained from port (77), the
directions of each component reverse, thereby
causing the motor to run in reverse direction.
16
Stopping Suppose the machine is traveling, with
pressure oil supplied to port (77) in rear flange
(27). As soon as this supply is shut off, spool
(48) tends to move back to its neutral position
due to the force of spring (54), because the
hydraulic pressure that pushes spool (48) is
lost. In this case, the oil in spool chamber
(89) tries to flow into port (77) through passage
(88), pushing spool (48). However, because the
oil flow is restricted at passage (88), back
pressure occurs which in turn slows down the
movement of spool (48). The motor keeps running
by inertia even when the pressure oil is stopped.
The motor return oil therefore tries to flow
back to port (76) from kidney port (82-2) in
timing plate (35) through passage (85), a
clearance between the recess of spool (48) and
rear flange (27). When spool (48) returns fully
to the neutral position, it blocks the motor
return line completely, thereby forcing the motor
to a halt. To smoothly stop the motor running by
inertia, the counter-balance valve slows down the
movement of spool (48) using the back pressure
generated by restricting the motor return line
through the recess shape of spool (48).
17
When the brake is applied to stop the motor, the
motor keeps rotating by inertia if pressure oil
is stopped, and act as a pump. However, oil is
no longer supplied because the suction line is
blocked by spool (48), thereby inducing possible
cavitation. Valve (52), which takes action at a
slight negative pressure under this condition,
then causes the oil to flow into kidney port
(82-1) in timing plate (35) from port (76) so as
to prevent cavitation.
When pressure oil is supplied to port (76) in
rear flange (27) during operation, each of the
above components moves reversely, forcing the
motor to a halt.
18
Overspeeding As the machine goes down a steep
slope, its speed increases, and the motor will
run faster than oil can be supplied. This faster
motor rotation is called "overspeed". When this
happens, port (77) goes negative to pull the
oil, moving spool (48) to the right. As a result,
return passage (85) is restricted, which in turn
causes back pressure. This back pressure causes a
resistance to the motor which tries to overspeed
by inertia so that the motor will run in
accordance with the flow rate of oil supplied
from the pump.
19
Parking brake Starting and travelling (Parking
brake released) When the pressure oil moves
spool (48) of the counter-balance valve to the
left from the neutral position, passage (86) to
the parking brake opens. And the pressure oil
pushes valve (45) until it closely contacts with
the bottom face of valve seat (44). This blocks
passage (90) to the drain port. Thus, the
pressure oil enters piston chamber (91) through
passage (92). As the pressure rises beyond the
set value, it overcomes the force of spring (39)
that pushes piston (38), and forces spring (38)
to move. The movement of piston (38) eliminates
the force of spring (38) which is acting on
separator plates (42) and friction plates (41)
and allows friction plates (41) in cylinder
block (30) of the travel motor to freely rotate,
thereby releasing the brake force acting on
cylinder block (30) of the travel motor.
20
Stopping (Parking brake applied) When the
supply of pressure oil is shut off, spool of the
counter-balance valve returns to the neutral
position. Passage (86) which is connected to the
parking brake closes and there is no
pressure. Consequently, spring (46) moves valve
(45) away from the surface of valve seat (44).
The pressure oil in piston chamber (91) goes
through passages (92) and (90) to port (75). The
drain is then led to the tank. There is no
longer pressure in piston chamber (91) and spring
(39) forces piston (38) against the inner
surface of the spindle. When piston (38) is
pushed, free separator plates (42) and friction
plates (41) are also pushed to spindle (2). The
friction force caused by this pushing force
stops the rotation of cylinder block, thereby
causing the brake torque to act on the motor
shaft.
21
Reduction gear When shaft (28) of the motor makes
one turn, input gear (6) that is splined to shaft
(28) also makes one turn. Three spur gears (7)
whose involute teeth are engaged with input gear
(7) rotate in reverse direction to one another.
Each spur gear (7) rotates at a speed, inversely
proportional to the gear ratio. The rotational
speed and direction of crankshaft (9) are the
same as those of spur gear (7), since they are
directly connected with splines.
22
When crankshaft (9) rotates, eccentric portions
(93) and (94) also rotate and provide eccentric
movement to gear A (4) and gear B (5).
23
Each gear A or B has 35 teeth. As gear A (4) and
gear B (5) start eccentric movement, their
trochoid teeth rotate in rolling contact with 36
pins (12) which are located on the inside surface
of hub (1). When crankshaft (9) makes one turn,
gear A (4) and gear B (5) perform one cycle of
eccentric movement, respectively. During this
one cycle, pin (12) shifts by one pitch, a
difference between 36 pins and 35 teeth, in the
same direction as crankshaft (9) rotates. This
pin rotation is transmitted to hub (1). Hub (1)
advances by 1 pin. The ratio is 1/36. The overall
reduction ratio is 1/57.6. This ratio is
obtained by multiplying the reduction ratio 15/24
between input gear (6) and spur gear (7) by the
reduction ratio 1/36 due to eccentric movement.
Copyright 1993 - 2019 Caterpillar Inc. All
Rights Reserved. Private Network For SIS
Licensees.
Fri Aug 30 192906 UTC0800 2019
24
Shutdown SIS
Previous Screen
Product EXCAVATOR Model E70B EXCAVATOR
6AK Configuration E70B TRACK-TYPE EXCAVATOR
6AK00001-UP (MACHINE) POWERED BY 4D32 ENGINE
General Service Information E70B EXCAVATOR TRAVEL
DRIVE AND MOTOR Media Number -SENR4584-00 Publicat
ion Date -01/08/1989
Date Updated -11/10/2001

• Disassembly
• Preparation
• Make the following preparations prior to
  disassembly.
• 1. Workbench
• Prepare the travel motor workbench. The
  workbench must be sturdy and large enough to
  disassemble or reassemble the travel motor and to
  hold its disassembled parts during work.
• 2. Supplies
• Prepare the supplies and special tools shown in
  the previous section.
• General Precautions
• Before starting the disassembling work, check the
  specified inspection items to see the nature of
  trouble. And follow the disassembly procedures.
• Use care in handling precision parts during work
  to avoid damage caused by striking other parts
  or from being dropped.
• Never strike or prize parts forcibly when they
  are held fast to prevent damage, burring, oil
  leakage or deteriorated performance. Use care and
  patient.
• Protect parts from corrosion and dust when
  disassembly is interrupted for some time. Parts
  rust easily due to moisture or dust when left
  disassembled.
• Disassembly Procedure

25

• Washing travel motor
• Fit a blind plug into each port in rear flange
  (27).
• Install and tighten two eye bolts 180 apart in
  the tapped holes in spindle (2).
• Hitch a lifting sling to the eye bolts through
  shackles. Lift and bring the travel motor over to
  the washing sink.

4. Wash the travel motor with a brush and
kerosene. NOTE Some dirt will be found in the
running clearance (where the floating seal is
installed) between hub (1) and spindle (2). Wash
the dirt off thoroughly.
Draining gear oil 1. Loosen three plugs (25) with
a torque wrench and hexagon socket. NOTE If the
motor is lifted with the plugs (25) removed, the
gear oil will come out. Loosen these plugs until
each plug comes out with its one or two threads
remaining in the cover.
26

1. Run two eye bolts into spindle (2) 180 apart.
2. Hitch a lifting sling to the eye bolts through
   shackles and lift the travel motor with the crane.

4. Place a clean vessel under the travel motor
and drain the gear oil into the vessel by
removing three plugs (25) from cover (8).
Setting travel motor 1. Set the travel motor on
the travel motor fixture. NOTE Place the travel
motor carefully with the bolt holes of hub (1)
and the fixture aligned.
27
2. Bolt the travel motor unit to the bench using
two hexagon bolts.

• Removing cover (8)
• Turn the travel motor upside down.
• Using an oil paint marker, scribe match marks
  across the joint seam between hub (1) and cover
  (8).

3. Look into the seam to locate the gap of ring
(13). Make a punch mark on hub (1) at a point
about 20 mm (0.787 in.) from the end of ring (13)
in circular direction and 6.5 mm (0.256 in.)
from its top end face.
28
4. Using an electric drill, make a 2 mm (0.079
in.) diameter hole at the punch mark, from the
outside of hub (1) toward ring (13). NOTE Be
sure to center the drill on the punch mark, and
keep drilling until ring (13) is pushed up from
cover (8) by the drill. NOTICE After drilling,
wipe off chippings completely. This is necessary
to protect parts which are disassembled
subsequently.
5. Insert the ring pick, a special tool, into the
drilled hole. Push ring (13) with this tool until
the end of ring (13) comes out of cover (8).
Hold the raised ring end by hand and remove ring
(13) from the groove of hub (1).

1. Run PT eye bolts into threaded holes on top of
   cover (8) and tighten.
2. Hitch a lifting sling to the PT eye bolts through
   shackles and lift cover (8) off hub (1) with a
   crane.

29
NOTE O-ring (22) may prevent cover (8) from
sliding out. If cover (8) will not move, lift the
cover while tapping on it with a plastic
hammer. 8. Remove O-ring (22) from cover
(8). NOTICE Do not use any sharp tools such as
a screwdriver to remove O-ring (22). The use of
such a sharp tool may cause burrs, galls, etc.,
in the groove. Oil leaks will be the result if
the O-ring is installed in the damaged groove.

• Removing input gear (6)
• Remove snap ring (20) from shaft (28).
• Remove input gear (6) from shaft (28).

• Removing rear flange (27)
• Turn the travel motor upside down.
• Loosen two plugs (49).
• NOTE This step is necessary only when the rear
  flange is to be disassembled, and a preliminary
  work to make it easier to remove plugs (49). So,
  do not try to remove plugs (49) but loosen them
  to the extent where they can be removed by hand.

30
3. Loosen two plugs (51). NOTE This step is
also necessary only when the rear flange is to be
disassembled and a preliminary work to make it
easier to remove plugs (51).
4. Remove hexagon socket bolts (67).
5. Remove rear flange (27) from spindle (2), and
put the removed rear flange on the bench with its
mating face with spindle (2) on
top. NOTICE Hold rear flange (27) with both
hands, and gently lift it straight up. Do not
cock it while lifting it. Any attempt to shake it
loose by tapping or otherwise is not permitted.
Remember, timing plate (35), a very critical
part, may come out with the rear flange.
6. Remove parallel pins (64) from spindle (2).
31
7. Remove O-ring (23) from spindle
(2). NOTICE Do not use any sharp tools such as
screwdriver to remove O-ring (23). The use of
such a sharp tool may cause burrs, galls, etc.,
in the groove. Oil leaks will be the result if
the O-ring is installed in the damaged groove.
8. Remove springs (39) from spindle (2).
Removing parts from rear flange 1. Remove timing
plate (35) from rear flange (27). NOTE It might
be found that the timing plate is stuck to the
mating surface of rear flange (27). To separate
the plate from the flange, insert a flat lever
into the cast-out groove of the rear flange and
prise the plate slowly. NOTICE Never try to
pry the plate off with a sharp cornered or
pointed tools such as a screwdriver, or the
precision-finished mating faces will be damaged,
resulting in oil leakage.
32
Suggest If the above button click is invalid.
Please download this document first, and then
click the above link to download the complete
manual. Thank you so much for reading
33

1. Pull parallel pins (65) out of rear flange (27).
2. Remove ball bearings (56) from rear flange (27).

Disassembling brake valve in rear flange 1. Put
rear flange (27) on the workbench with its mating
face with spindle (2) on bottom. NOTICE The
bench top surface must be clean, flat and free of
scar to avoid any damages to the
precision-finished surface of the rear flange.

1. Remove two plugs (49) from rear flange (27) by
   hand.
2. Remove O-ring (62) from each plug (49).

1. Remove two spring retainers (50) and two springs
   (54) from rear flange (27).
2. Remove spools (48) from rear flange (27).

34
https//www.ebooklibonline.com Hello dear
friend! Thank you very much for reading. Enter
the link into your browser. The full manual is
available for immediate download. https//www.eb
ooklibonline.com