Hitachi DH 18DL Technical Data And Service Manual

Brand: Hitachi

Model: DH 18DL

Category: Power drills

Type: Technical Data And Service Manual

This manual is also suitable for

• Drilling anchor holes

• Drilling holes in concrete, tile, brick, and similar materials

• Drilling holes in steel and wood

• Ti

htenin

and loosenin

machine screws and wood screws

PRODUCT NAME

Hitachi 14.4 V Cordless Rotary Hammer

Model DH 14DL, DH 14DMR

Hitachi 18V Cordless Rotary Hammer

Model DH 18DL, DH 18DMR

[ NEW FEATURES ]

Fastest drilling speed

Compact & lightweight

Switchable hammering force mechanism

Soft grip handle

Li-ion battery for DH 14DL/DH 18DL,

Ni-Cd battery for DH 14DMR/DH 18DMR

Replaceable carbon brush for longer motor life

Idle striking prevention mechanism

With light hook

The Models DH 14DL and DH 18DL are cordless rotary hammers equipped with a 14.4-V lithium-ion battery and

a 18-V lithium-ion battery respectively.

The Models DH 14DMR and DH 18DMR are cordless rotary hammers equipped with a 14.4-V Ni-Cd battery and

a 18-V Ni-Cd battery respectively.

(1) Fastest drilling speed

(2) Compact and lightweight

(3) Switchable hammering force mechanism

(4) Soft grip handle

We aim to expand our market share with the new Models DH 14DL/DH 14DMR/DH 18DL/DH 18DMR.

LIST Nos.

DH 14DL: G876,

DH 14DMR: G877,

DH 18DL: G878,

DH 18DMR: G879

Jul. 2007

MARKETING OBJECTIVE

APPLICATIONS

SELLING POINTS

International Sales Division

SPECIFICATIONS AND PARTS ARE SUBJECT TO CHANGE FOR IMPROVEMENT

REMARK:

For more information about HANDLING INSTRUCTIONS, visit our website at:

http://www.hitachi-koki.com/manual_view_export/

Throughout this TECHNICAL DATA AND SERVICE MANUAL, a symbol(s) is(are) used in the place of

company name(s) of out competitor(s). The symbol(s) utilized here is(are) as follows:

Competitors

Symbols Utilized

Company Name Model Name

C MAKITA BHR162SFE

CONTENTS

Page

SELLING POINT DESCRIPTIONS-----------------------------------------------------------------------------------------1

SPECIFICATIONS --------------------------------------------------------------------------------------------------------------4

COMPARISONS WITH SIMILAR PRODUCTS--------------------------------------------------------------------------8

1. Specifications comparisons------------------------------------------------------------------------------------8

2. Drilling speed comparisons ------------------------------------------------------------------------------------9

3. Per charge working capacity comparisons---------------------------------------------------------------10

PRECAUTIONS IN SALES PROMOTION------------------------------------------------------------------------------11

1. Safety Instructions ---------------------------------------------------------------------------------------------11

2. Precautions Requiring Particular Attention During Sales Promotion ------------------------------13

REFERENCE MATERIALS-------------------------------------------------------------------------------------------------14

1. Lubrication -------------------------------------------------------------------------------------------------------14

2. Tool structure----------------------------------------------------------------------------------------------------14

3. Changeover between “Rotation only” and “Rotation and hammering” ----------------------------15

4. Precautions for use of “Rotation only” (no striking) function -----------------------------------------16

5. Drill bits -----------------------------------------------------------------------------------------------------------16

6. Tool retainer section -------------------------------------------------------------------------------------------17

7. Dust collector (B)-----------------------------------------------------------------------------------------------18

REPAIR GUIDE----------------------------------------------------------------------------------------------------------------19

1. Precautions in Disassembly and Reassembly ----------------------------------------------------------19

2. Precautions in Disassembly and Reassembly of Battery Charger ---------------------------------30

STANDARD REPAIR TIME (UNIT) SCHEDULES--------------------------------------------------------------------31

Assembly Diagram for DH 14DL

Assembly Diagram for DH 14DMR

Assembly Diagram for DH 18DL

Assembly Diagram for DH 18DMR

Save mode

(

)

Power mode (P)

Rotation change

lever

Change lever

Shift knob

“Rotation + hammering”

“Rotation only”

“POWER”

mode

(Powerful

hammering

force)

Suitable for drilling holes

of 4.3 mm or larger

diameter with high motor

power (speedy and

efficient drilling)

Suitable for drilling holes

in steel and wood

speedily with high motor

power

“SAVE”

mode

(Suppressed

hammering

force)

Suitable for drilling holes

of 4 mm or smaller

diameter with suppressed

motor power (preventing

the bit from being bent)

CAUTION:

Do not use the tool for

high-load operation in

this mode because the

motor power is

suppressed. Otherwise,

the motor may be burnt

out.

Fastest drilling speed

The drilling speed of the Models DH 14DL, DH 14DMR, DH 18DL and DH 18DMR are 1.05 times higher

than C thanks to the efficient transmission of the hammering energy. For detail refer to “Drilling Speed

Comparisons” on page 9.

Compact and lightweight

The Models DH 14DL, DH 14DMR, DH 18DL and DH 18DMR are most compact and lightweight in the class.

(Overall length L1: DH 14DL/DH 14DMR/DH 18DL/DH 18DMR: 324 mm)

(Overall length L2: DH 14DL/DH 14DMR/DH 18DL/DH 18DMR: 251 mm)

(Weight: DH 14DL: 2.1 kg DH 14DMR: 2.4 kg DH 18DL: 2.3 kg DH 18DMR: 2.6 kg)

Switchable hammering force mechanism

The Model are equipped with the switchable hammering force mechanism to prevent small-diameter bits

(4 mm or less) from being bent. The hammering force can be adjusted by switching between power mode

(P) and save mode (S).

Soft grip handle

The handles are widely covered with soft-touch elastomer (rubber-like soft resin). It is slip-resistant and

securely fits in the palm of a hand even if the gripping hand sweats.

SELLING POINT DESCRIPTIONS

Equipped with the new lithium-ion battery

Each of the Types BCL 1430 and EBM 1830 lithium-ion batteries is equipped with the overdischarge

protection circuit, overload protection circuit, and voltage monitoring circuit for each cell to prevent

reduction of the battery life due to overdischarge (overuse) or overcharge (excessive charging) of the

battery. The number of charging/discharging is about 1,500. Precautions for use of the Types BCL 1430

and EBM 1830 lithium-ion batteries.

Each of the Types BCL 1430 and EBM 1830 lithium-ion batteries is equipped with a protective function that

automatically stops output to extend the battery life. The motor may stop automatically in either of the

following case or even if the switch is depressed continuously during operation. This is because the

protective function is activated. The battery is not faulty.

The motor may stop automatically when the remaining battery level is low (when the battery voltage is

decreased to about 8V (Type BCL 1430)/when decreased to about 12 V (Type EBM 1830)). Charge the

battery immediately in such case.

The motor may stop if the Models DH 14Dland DH 18DL are overloaded. In such case, release the switch

and eliminate the cause of the overload problem. Then the Models DH 14DL and DH 18DL are operable.

Replaceable carbon brush for longer motor life

The carbon brushes are replaceable from the outside. Take out the carbon brush by first removing the

brush cap and then hooking the protrusion of the carbon brush with a slotted head screw driver, etc. When

installing the carbon brush, choose the direction so that the nail of the carbon brush agrees with the contact

portion outside the brush tube. Then push it in with a finger Lastly, install the brush cap.

Idle striking prevention mechanism

The idle striking prevention mechanism in the Models DH 14DL, DH 14DMR, DH 18DL and DH 18DMR are

different from those of conventional hammer drills in other classes. When the drill bit is lifted from the

concrete surface on completion of drilling or during no-load operation, the reciprocating bearing that

converts rotation into reciprocating motion stops to prevent idle striking.

Upon lifting the drill bit from the concrete surface, the tool shaft (cylinder) is moved forward about 5 mm by

the force of spring (B). Then the clutch is moved forward by the thrust plate that is connected to the cylinder

to disengage the clutch from the reciprocating bearing. Thanks to the needle bearing on the second shaft,

the reciprocating bearing can idle. Accordingly, rotation of the second shaft is not transmitted to the

reciprocating bearing and the reciprocating bearing stops to stop the striking motion of the piston and the

striker. The pressing force of spring (B) is as low as 1.0 kg to 2.0 kg in comparison with the conventional

mouth system. The Models DH 14DL, DH 14DMR, DH 18DL and DH 18DMR are also suitable for drilling in

upward direction.

With light hook

(1) The hook can be quickly slid out whenever necessary and slid in when not necessary.

(2) The hook is mountable on either side using a flat-blade screwdriver or a coin.

(3) The angle of the hook is adjustable in five steps.

Angle-adjustable in 5 steps

Mountable on either side

Strike

Slide plate

Cylinder

Clutch

Cylinder flange

Reciprocating bearing

Piston

Coil spring

Needle bearing

Tool shaft

Second gear

Spring (B)

Slip mechanism

Model

DH 14DL

Concrete

16 mm (5/8”)

Steel 13 mm (1/2”)

Capacity

Wood 18 mm (11/16”)

Usable drill bits

SDS-plus type only

No-load rotation speed “POWER” mode: 1,500 min

–1

, “SAVE” mode: 750 min

-1

Full-load blow

“POWER” mode: 6,200 min

–1

, “SAVE” mode: 3,100 min

-1

Type of motor

DC magnet motor

Type of switch

Trigger switch with forward/reverse rotation selector (with brake)

Type of handle Gun-type handle of main body and side handle

Enclosure

Housing------------------ Glassfiber reinforced polycarbonate resin and elastomer

Gear cover-------------- Glassfiber reinforced polyamide resin and elastomer

Battery ------------------- Glassfiber reinforced polycarbonate resin (black)

Charger------------------ ABS resin

Battery

(Type: BCL 1430)

Sealed cylindrical lithium-ion storage battery

Nominal voltage ----------------------- DC 14.4V

Nominal life ----------------------------- Charging/discharging: Approx. 1,500 times

Nominal capacity ---------------------- 3.0 Ah

Charger

(Model UC 18YRL)

Overcharge protection system:

(1) Battery voltage detection (- V system)

Battery temperature detection (dT/dt system) for Ni-MH and SUPER Ni-MH

batteries

(2) Battery surface temperature detection (thermistor)

(3) 120-minute timer

(4) Stop current detection (Li-ion batteries)

Power input: 95 W

Charging time: Approx. 45 minutes [for Type BCL 1430 battery at 20°C (68°F)]

Operable ambient temperature range: 0°C

40°C (32°F

104°F)

The maximum allowable temperature of the Type BCL 1430 battery is

50°(122°F).

Weight Net

Main body unit (including battery) -------------------------------------2.1 kg (4.6 lbs.)

Charger unit (UC 18YRL, including cord) ----------------------------0.6 kg (1.3 lbs.)

Gross DH 14DL (2LRK) -----------------------------------------------------------6.2 kg (13.7 lbs)

DH 14DL (NN) --------------------------------------------------------------2.3 kg (5.1 lbs)

(2LRK)

Charger (UC 18YRL)------------------------------------------------------------------------1

Battery (BCL 1430) --------------------------------------------------------------------------2

Side handle------------------------------------------------------------------------------------1

Depth gauge-----------------------------------------------------------------------------------1

Plastic case------------------------------------------------------------------------------------1

Standard

accessories

(NN) Without charger, plastic case and battery

SPECIFICATIONS

Model

DH 18DL

Concrete

16mm (5/8”)

Steel 13mm (1/2”)

Capacity

Wood 18mm (11/16”)

Usable drill bits

SDS-plus type only

No-load rotation speed “POWER” mode: 1,500 min

–1

, “SAVE” mode: 750 min

–1

Full-load blow

“POWER” mode: 6,200 min

–1

, “SAVE” mode: 3,100 min

-1

Type of motor

DC magnet motor

Type of switch

Trigger switch with forward/reverse rotation selector (with brake)

Type of handle Gun-type handle of main body and side handle

Enclosure

Housing------------------ Glassfiber reinforced polycarbonate resin and elastomer

Gear cover-------------- Glassfiber reinforced polyamide resin and elastomer

Battery ------------------- Glassfiber reinforced polycarbonate resin (black)

Charger------------------ ABS resin

Battery

(Type: EBM 1830)

Sealed cylindrical lithium-ion storage battery

Nominal voltage ------------------------DC 18V

Nominal life ------------------------------Charging/discharging: Approx. 1,500 times

Nominal capacity-----------------------3.0 Ah

Charger

(Model UC 18YRL)

Overcharge protection system:

(1) Battery voltage detection (- V system)

Battery temperature detection (dT/dt system) for Ni-MH and SUPER Ni-MH

batteries

(2) Battery surface temperature detection (thermistor)

(3) 120-minute timer

(4) Stop current detection (Li-ion batteries)

Power input: 95 W

Charging time: Approx. 45 minutes [for Type EBM 1830 battery at 20°C (68°F)]

Operable ambient temperature range: 0°C

40°C (32°F

104°F)

The maximum allowable temperature of the Type EBM1830 battery is 50°C

(122°F)

Weight Net

Main body unit (including battery) ------------------------------------- 2.3 kg (5.1 lbs.)

Charger unit (UC 18YRL, including cord) ---------------------------- 0.6 kg (1.3 lbs.)

Gross DH 18DL (2MRK) ---------------------------------------------------------- 6.4 kg (14.1 lbs)

DH 18DL (NN) -------------------------------------------------------------- 2.3 kg (5.1 lbs)

(2MRK)

Charger (UC 18YRL) -----------------------------------------------------------------------1

Battery (EBM 1830) -------------------------------------------------------------------------2

Side handle------------------------------------------------------------------------------------1

Depth gauge-----------------------------------------------------------------------------------1

Plastic case------------------------------------------------------------------------------------1

Standard

accessories

(NN) Without charger, plastic case and battery

Model

DH 14DMR

Concrete

16mm (5/8”)

Steel 13mm (1/2”)

Capacity

Wood 18mm (11/16”)

Usable drill bits

SDS-plus type only

No-load rotation speed “POWER” mode: 1,500 min

–1

, “SAVE” mode: 750 min

–1

Full-load blow

“POWER” mode: 6,200 min

–1

, “SAVE” mode: 3,100 min

-1

Type of motor

DC magnet motor

Type of switch

Trigger switch with forward/reverse rotation selector (with brake)

Type of handle Gun-type handle of main body and side handle

Enclosure

Housing---------------- Glassfiber reinforced polycarbonate resin and elastomer

Gear cover------------ Glassfiber reinforced polyamide resin and elastomer

Battery ----------------- Glassfiber reinforced polycarbonate resin (black)

Charger---------------- ABS resin

Battery

(Type: EB 14B)

Sealed cylindrical Ni-Cd storage battery

Nominal voltage ----------------------DC 14.4 V

Nominal life ----------------------------Charging/discharging: Approx. 1,000 times

Nominal capacity ---------------------2.0 Ah

Charger

(Model UC 18YG)

Overcharge prevention circuit:

A thermostat monitors the surface temperature of the battery and, on detecting

the temperature rise which occurs on completion of charging, automatically

turns off the unit to prevent the battery from overcharge.

Output capacity: 70 W

Indication method: Pilot lamp indicator of battery charging

Function: On---------------------------------------------------------During charging

Off---------------------------------------------------------Charging completed

Weight Net

Main body unit (including battery) -------------------------------------2.4kg (5.3 lbs.)

Charger unit (UC 18YG, including cord) -----------------------------0.3kg (0.66 lbs.)

Gross DH 14DMR (2BGK) ------------------------------------------------------- 6.5kg (14.3 lbs)

DH 14DMR (NN) ----------------------------------------------------------- 2.3kg (5.1 lbs)

(2BGK)

Charger (UC 18YG) -------------------------------------------------------------------------1

Battery (EB 14B) -----------------------------------------------------------------------------2

Side handle------------------------------------------------------------------------------------1

Depth gauge-----------------------------------------------------------------------------------1

Plastic case------------------------------------------------------------------------------------1

Standard

accessories

(NN) Without charger, plastic case and battery

Model

DH 18DMR

Concrete

16mm (5/8”)

Steel 13mm (1/2”)

Capacity

Wood 18mm (11/16”)

Usable drill bits

SDS-plus type only

No-load rotation speed “POWER” mode: 1,500 min

–1

, “SAVE” mode: 750 min

–1

Full-load blow

“POWER” mode: 6,200 min

–1

, “SAVE” mode: 3,100 min

-1

Type of motor

DC magnet motor

Type of switch

Trigger switch with forward/reverse rotation selector (with brake)

Type of handle Gun-type handle of main body and side handle

Enclosure

Housing---------------- Glassfiber reinforced polycarbonate resin and elastomer

Gear cover------------ Glassfiber reinforced polyamide resin and elastomer

Battery ----------------- Glassfiber reinforced polycarbonate resin (black)

Charger---------------- ABS resin

Battery

(Type: EB 1820L)

Sealed cylindrical Ni-Cd storage battery

Nominal voltage ----------------- DC 18 V

Nominal life ----------------------- Charging/discharging: Approx. 1,000 times

Nominal capacity ---------------- 2.0 Ah

Charger

(Model UC 18YG)

Overcharge prevention circuit:

A thermostat monitors the surface temperature of the battery and, on detecting

the temperature rise which occurs on completion of charging, automatically

turns off the unit to prevent the battery from overcharge.

Output capacity: 70 W

Indication method: Pilot lamp indicator of battery charging

Function: On-----------------------------------------------------------During charging

Off-----------------------------------------------------------Charging completed

Weight Net

Main body unit (including battery) --------------------------------------2.6 kg (5.7 lbs.)

Charger unit (UC 18YG, including cord) ------------------------------0.3 kg (1.3 l bs.)

Gross DH 18DMR (2BGK) --------------------------------------------------------6.8 kg (15.0 lbs)

DH 18DMR (NN) ------------------------------------------------------------2.3 kg (5.1 lbs)

(2BGK)

Side handle-------------------------------------------------------------------------------------1

Depth gauge------------------------------------------------------------------------------------1

Charger (UC 18YG) --------------------------------------------------------------------------1

Plastic case-------------------------------------------------------------------------------------1

Battery (EB 1820L) ---------------------------------------------------------------------------2

Standard

accessories

(NN) Without charger, plastic case and battery

(Superior specifications:

)

1. Specifications comparisons

Maker HITACHI

Model name DH 14DL DH 18DL DH 14DMR DH 18DMR

Concrete 16 mm (5/8”) 16 mm (1/2”)

Steel 13 mm (1/2”) 13 mm (1/2”)

Capacity

Wood 18 mm (11/16") 24 mm (15/16")

No-load rotation speed (P) mode: 1,500 min

–1

, (S) mode: 750 min

–1

1500 min

–1

Full-load blow (P) mode: 6,200 min

–1

, (S) mode: 3,100 min

–1

5,000 min

–1

Changeover of impact energy Equipped

Not indicated

Bit setting Single action

Single action

Reversing switch Push-button

Push-button

Changeover modes 2 modes

2 modes

Soft grip handle Equipped (Handle and Gear cover)

Equipped (Handle)

Externally accessible CB Equipped

Equipped

Variable speed Equipped Equipped

Internal pressure adjustment

mechanism

Equipped Not indicated

Belt hook Equipped Not indicated

LED light Equipped Equipped

Type Li-ion Ni-Cd Li-ion

Nominal capacity 3.0 Ah 3.0 Ah 2.0 Ah 2.0 Ah 3.0 Ah

Nominal voltage 14.4 V 18 V 14.4 V 18 V 14.4 V

Protection circuit Equipped Equipped – – Not indicated

Battery

Charging time*

45 min 50 min 22 min

Overall length L1*

Overall length L2

324 mm

251 mm

296 mm

255 mm

Overall height 260 mm 263 mm 258 mm 263 mm 250 mm

Dimensions

Overall width 67 mm 67 mm

Weight 2.1 kg 2.3 kg 2.4 kg 2.6 kg 2.1 kg

: Charging time may vary depending on the type of charger to be used.

: L1: Overall length from the tip to the lower section of the handle

L2: Overall length from the tip to the upper section of the handle

COMPARISONS WITH SIMILAR PRODUCTS

2. Drilling speed comparisons

Drilling speed depends on the operating conditions. The test result is based on actual factory tests, and is

used as a reference only. The drilling speed comparisons for downward drilling. The drill bits used are the

Hitachi genuine SDS-plus shank bits.

100

200

300

400

500

600

700

2 4 6 8 10 12 14 16 18

Drill diameter (mm)

Hitachi

DH14DL/DH14DMR/

DH18DL/DH18DMR

Drilling speed (mm/min.)

Pressing force: 10kgf

Test material: Concrete panel with

A compression strength of 240 kgf/cm

3. Per charge working capacity comparisons

The number of holes which can be drilled into concrete per battery charge may vary widely in accordance

with the hardness of the concrete, the sharpness and condition of the drill bit and other factors. Accordingly,

the test results are intended for reference purposes only.

1. Safety Instructions

In the interest of promoting the safest and most efficient use of the Models DH14DL/DH14DMR/DH18DL/

DH18DMR Cordless Rotary Hammers by all of our customers, it is very important that at the time of sale,

the salesperson carefully ensures that the buyer seriously recognizes the importance of the contents of the

Handling Instructions, and fully understands the meaning of the precautions listed on the Caution Plate and

Name Plate attached to each tool.

A. Handling Instructions

Salespersons must be thoroughly familiar with the contents of the Handling Instructions in order to give

pertinent advice to the customer. In particular, they must have a thorough understanding of the precautions

for use of the cordless tools which are different from those of ordinary electric power tools.

(1) Before use, ensure that the unit is fully charged.

New units are not fully charged. Even if the units were fully charged at the factory, long periods of

inactivity, such as during shipping, cause the storage battery to lose its charge. Customers must be

instructed to fully charge the unit prior to use.

(2) Connect the charger to an AC power outlet only.

Use of any other power source (DC outlet, fuel powered generator, etc.) will cause the charger to

overheat and burn out.

(3) Do not use any voltage increasing equipment (transformer etc.) between the power source and the charger.

If the charger is used with voltage higher than that indicated on the unit, it will not function properly.

(4) Conduct battery charging at an ambient temperature range of 0°C

40°C (32°F

104°F).

Special temperature sensitive devices are employed in the charger to permit rapid charging. Ensure that

customers are instructed to use the charger at the indicated ambient temperature range. At temperature

under 0°C (32°F) the thermostat will not function properly, and the storage battery may be overcharged.

At temperature over 40°C (104°F), the storage battery cannot be sufficiently charged. The optimum

temperature range is 20°C

25°C (68°F

77°F).

(5) The battery charger should not be used continuously.

At high ambient temperature, if over three storage batteries are charged in succession, the temperature

of the coils on the transformer will rise and there is a chance that the temperature fuse inserted in the

interior of the transformer will inadvertently melt. After charging one battery, please wait about 15

minutes before charging the next battery.

(6) Do not insert foreign objects into the air vents on the charger.

The charger case is equipped with air vents to protect the internal electronic components from

overheating. Caution the customer not to allow foreign materials, such as metallic or flammable objects,

to be dropped or inserted into the air vents. This could cause electrical shock, fire, or other serious

hazards.

(7) Do not attempt to disassemble the storage battery or the charger.

Special devices, such as a thermostat, are built into the storage battery and charger to permit rapid

charging. Incorrect parts replacement and/or wiring will cause malfunctions which could result in fire or

other hazards. Instruct the customer to bring these units to an authorized service center in the event

repair or replacement is necessary.

(8) Disposal of the storage batteries

Ensure that all customers understand that Type storage batteries should be returned to the Hitachi

power tool sales outlet or the authorized service center when they are no longer capable of being

recharged or repaired. If thrown into a fire, the battery may explode, or, if discarded indiscriminately,

leakage of the cadmium compound contained in the battery may cause environmental pollution.

PRECAUTIONS IN SALES PROMOTION

B. Caution Plate

(1) The following cautions are listed on the Name Plate attached to the main body of each tool.

[ For the U.S.A. and Canada ]

(2) The following cautions are listed on the name plate attached to each storage battery.

[ For Europe ]

[ For the U.S.A. and Canada ]

(3) The following cautions are listed on the Name Plate attached to the Model UC 18YRL or UC 18YG

Charger.

2. Precautions Requiring Particular Attention During Sales Promotion

The cordless rotary hammer offers many advantages: it can be used in places where no power source is

available, the absence of a cord allows easy use, etc. However, in comparison with conventional AC type

impact drills and hammer drills, there are certain precautions which require particular attention.

Salespersons must be thoroughly familiar with the following points to properly advise the customer in the

most efficient use of the tool.

A. Suggestions and precautions for the efficient use of the tool

(1) Appropriate drilling capacity of the Model DH 14DL/DH 14DMR/DH 18DL/ DH 18DMR

The Models DH 14DL, DH 14DMR, DH 18DL and DH 18DMR are not capable of drilling several dozens

of holes like a conventional AC type impact or hammer drill because it is a cordless rotary hammer

recommend that a spare battery should be kept available for use.

(2) Use thrust within the range of 10 to 15 kg

Applying heavy thrust (pressure) on the tool, such as is possible with AC type impact and hammer drills,

will not accelerate the drilling speed. On the contrary, excessive pressure will reduce bit rotation and

hammering speed, and cause the storage battery to rapidly lose its charge.

(3) Variation in amount of work possible per charge

Although the nominal capacity of the storage batteries used with the Models DH 14DL/DH 8DL is 3.0 Ah

Models DH 14DMR/DH 18DMR is 2.0 Ah, the Actual capacity may vary within 10% of that value

depending on the ambient temperature during use and recharging, and the number of times the

batteries have been recharged. It should also be noted that other factors which may have a bearing on

the amount of work possible per charge are the working conditions (ambient temperature, type and

moisture content of the workpieces, sharpness of the drill bits, etc.) and the operational skill of the user.

(4) Precautions in drilling with metal drill bits.

Although the Models DH 14DL, DH 14DMR, DH 18DL and DH 18DMR are designed for a drilling

capacity of up to 13 mm in steel, its operational capabilities are considerably less than those of

conventional AC type impact drills. Especially when drilling with a 13 mm drill bit for steel, the drill tends

to become locked when the drill bit penetrates through the material. For this reason, the customer

should be cautioned to reduce the pressure on the main body of the tool when drilling completely

through the material to avoid locking the drill.

1. Lubrication

Replenish the grease lubricant when the tool is disassembled or there is grease leakage due to a defective

seal. Changing grease is required once a year to extend the service life of the tool. Special grease is used

in the striking section. Should the striking section (within the gear cover) be disassembled, remove the old

grease from all parts completely and, on reassembly, replenish 30 g of new grease in the gear cover and

10 g in the groove of the inner cover. Be careful not to exceed the designated amount of grease. Excessive

grease will reduce striking efficiency.

2. Tool structure

Transmission of rotation

See Fig. 1. The rotation of the armature is transmitted to the second shaft via the first gear, and causes

it to rotate. The second shaft pinion mounted on the second shaft engages the second gear mounted on

the outer circumference of the cylinder. The cylinder is coupled to the second gear by means of a slip

mechanism, and they rotate together. The end of the cylinder also functions as the drill bit retainer. The

cylinder is key-connected to the inserted drill bit by means of two key rails and a steel ball, and transmits

rotation to the drill bit.

Piston reciprocating mechanism

In the Models DH 14DL, DH 14DMR, DH 18DL and DH 18DMR, through adoption of a spiral drive

system (a mechanism using a reciprocating bearing), a more compact design has been achieved by

arranging the motor shaft in parallel with the tool shaft. Figure 1 shows that the drill bit is pressed

against the workpiece and the tool shaft is retracted. The rotation of the armature is transmitted to the

second shaft via the first gear. The second shaft rotation is further transmitted through a spline to the

clutch. The cylinder flange is pressed against the clutch by the retracted tool shaft and the clutch

engages with the reciprocating bearing to transmit rotation to the reciprocating bearing. However,

circular grooves on the inner race of the reciprocating bearing are positioned on an angle of inclination

with relation to the second shaft.

The rotation of the inner race and the shaft causes that angle of inclination to change regularly forward

and backward with relation to the second shaft, and produces a rocking motion to the outer race of the

reciprocating bearing. Finally, a rod extending from the outer race of the reciprocating bearing is

connected to the piston by the piston pin, and causes the reciprocating bearing motion of the piston.

REFERENCE MATERIALS

Rod

ir chambe

Striker

Slip mechanism

Steel ball

O-ring

Cylinder

Key rail (2 pcs.)

Tool shaft

Slide plate

Piston pin

Motor shaft

First gear

Slide plate

Reciprocating bearing

Second hammer

Second gear

Second pinion

Cylinder flange

Spline

Second shaft

Clutch

Piston

Fig. 1

Hammering function

The piston reciprocates within the cylinder to move the striker in the same manner as in conventional

hammer drills. As the piston reciprocates, the changing air pressure inside the air chamber between the

piston and the striker causes the striker to move and continuously strike against the end of the second

hammer. At the same time, the changing air pressure within the air chamber which moves the striker

also provides an “air cushion” which absorbs the impact of the hammering action. As any air leakage

from the air chamber would weaken the air-cushion effect and reduce impact absorption, the O-ring

(mounted on the striker) is extremely important to seal the air. Although special rubber material is

utilized in construction of the O-ring to make its effective service life as long as possible, wear cannot be

fully avoided. Accordingly, it is recommended that the O-ring be replaced approximately once a year,

depending on the frequency of usage of the tool.

Slip mechanism

The slip mechanism in the Models DH 14DL, DH 14DMR, DH 18DL and DH 18DMR consists of a coil

spring which applies a pre-set amount of pressure to ensure the interlocking of three claws provided on

the flange of the cylinder (the final rotating shaft) and three matching claws provided on the face of the

second gear, by which rotation is transmitted to the cylinder. The second gear is fitted to the cylinder

with a certain amount of play. If an excessively large torque is applied to the tool shaft (cylinder), the

force of the torque will exceed the pressure of the coil spring and cause the claws on the second gear to

disengage from and ride over the claws on the cylinder so that the second gear idles and does not

transmit rotation. Even should the drill bit come in contact with a reinforcing bar within the concrete,

causing sudden excessive torque, the slip mechanism functions to prevent damage to the gears, and

possible loss of control of the tool by the operator. The slip torque applied onto the tool shaft is set to 1.7

to 2.2 kgm.

Sealed and dustproof construction

The gear cover is totally enclosed by oil seals, O-rings and other devices to prevent leakage of

lubricating grease, and to keep dust and dirt out of the internal mechanisms. The drill bit chuck portion is

protected by the rubber front cap to keep out dust and chips which could cause improper fitting of the

drill bit and/or other faulty operation of the chuck portion. The speed control switch is also a fully dust-

proofed type to prevent dust and chips from entering the handle section and causing possible

operational trouble or a breakdown of the insulation.

Speed control

Each of the Models DH 14DL, DH 14DMR, DH 18DL and DH 18DMR is equipped with a variable speed

control switch which permits free change of the rotation speed and striking force. When drilling in fragile

materials, pull the switch trigger gently for low rotation speed (striking force) to achieve optimum results.

In the reverse rotation mode, the operator can pull the switch trigger only halfway and the rotation speed

is decreased to about half of the speed in the forward rotation mode. In addition, the switch stopper

cannot be used in the reverse mode.

3. Changeover between “Rotation only” and “Rotation and hammering”

The change lever of the Models DH 14DL, DH 14DMR, DH 18DL and DH 18DMR permits easy changeover

between the “rotation only” and “rotation and hammering” functions. Set the change lever to “rotation and

hammering” (

marks). Press the drill bit against the workpiece and pull the switch trigger. Then the

armature starts rotating, and the rotation and the striking force are transmitted to the drill bit by the

mechanism as described in page 14 “Piston reciprocating mechanism.” After drilling, take the drill bit

away from the workpiece. Then the rotation of the reciprocating bearing and the hammering operation

are stopped by the idle striking prevention mechanism as described in page 2. Set the change lever to

“rotation only” ( mark). The stopper of the change lever contacts the rear surface of the thrust plate

that is pushed forward by spring (B). Thus the cylinder cannot go back even if the main body is pressed,

and the claws on the clutch cannot engage the matching claws on the reciprocating bearing. The

reciprocating bearing idles on the second shaft and only the rotation is transmitted to the drill bit.

4. Precautions for use of “Rotation only” (no striking) function

Each of the Models DH 14DL, DH 14DMR, DH 18DL and DH 18DMR is equipped with a change lever for

changeover between “rotation only” and “rotation and hammering” functions. Be sure to set the change

lever to “rotation only” for drilling into wood or metal materials or for driving screws by means of the optional

chuck adapter or drill chuck. Should the change lever be set to “rotation and hammering” when such an

optional tool is used for drilling or driving screws, the hammering action may cause the drill chuck or other

optional tool to be broken or damaged. Salespersons should carefully ensure that the buyer is thoroughly

advised on this point.

5. Drill bits

The chuck section is designed exclusively for the popular and widely available SDS-plus shank bits, as

shown in Fig. 2. Rotating torque is transmitted to the drill bit by two key rails provided in the tool holding

section. A steel ball is used to prevent the bit from falling out.

The service life of a drill bit with a diameter of 8 mm is approximately 300 holes when drilling into concrete

with a depth of 30 mm. If reground before the end of its service life, the drill bit will continue to provide

efficient drilling. Figure 3 shows the regrinding angle.

Sectional view of chuck section

Cylinder

Key rail (2 pcs.)

Steel ball

Ball holder

Shape of the SDS-plus shank bit

Key slot

Section AA

Fig. 2

6. Tool retainer section

The tool retainer is structured as shown in Fig. 4.

The tip of the tool retainer is covered with the front cap (made of rubber) to prevent dust and chips from

getting inside. The steel ball falls into the round groove of the bit to prevent the tool from coming off and the

two key rails transmit the rotation torque. To mount the bit, push the bit in the tool retainer as far as it will go.

Pushing lightly, turn the bit until it is caught. At this position, push the bit in as far as it will go (sliding the grip

is not required for mounting the bit). To remove the bit, slide the grip backward to the full and remove the

bit.

Fig. 4

Grip

Ball holde

Holder s

rin

Steel ball

rail

(

cs.

)

Sto

er rin

Front ca

Cylinder

Holder plate

Rotation

Section A-B

Rotation

Fig. 3

a : b = 1:2

25°

130°

30°

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Hitachi DH 18DL Technical Data And Service Manual

Brand: Hitachi

Model: DH 18DL

Category: Power drills

Type: Technical Data And Service Manual

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Hitachi DH 18DL Technical Data And Service Manual

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Hitachi DH 18DL Technical Data And Service Manual

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