BÀI GIẢNG: HỆ THỐNG PHANH

Diagnosis Technician >> Brake >> Brake System

TRƯỜNG ĐẠI HỌC SƯ PHẠM KỸ THUẬT TP.HCM KHOA CƠ KHÍ ĐỘNG LỰC

HỆ THỐNG PHANH BRAKE SYSTEM

Diagnosis Technician >> Brake >> Brake SystemCÔNG DỤNG

Tạo ra lực cản ở bánh xe để: - Giảm tốc độ xe - Dừng xe - Hoặc đậu xe

Diagnosis Technician >> Brake >> Brake SystemPHÂN LOẠI

@ Theo chức năng: - Phanh chính - Phanh đậu xe

@ Theo dẫn động phanh:

- Phanh cơ khí - Phanh thủy lực - Phanh khí nén - Phanh thủy khí

Diagnosis Technician >> Brake >> Brake SystemPHÂN LOẠI

@ Theo cơ cấu phanh: - Phanh trống (guốc) - Phanh đĩa - Phanh đai @ Theo trợ lực phanh: - Trợ lực bằng chân không - Trợ lực bằng thủy lực - Trợ lực bằng khí nén

Ngoài ra, còn có: - Phanh bằng động cơ - Phanh khí xả

Diagnosis Technician >> Brake >> Brake SystemYÊU CẦU

- Lực phanh lớn và tác dụng nhanh (nhạy), có khả năng dừng xe gấp với thời gian và quãng đường phanh ngắn nhất - Hoạt động êm dịu, tính ổn định chuyển động của xe khi phanh cao - Lực phanh phân phối ở các bánh xe theo qui luật phân bố tải trọng - Lực tác dụng lên bàn đạp phanh nhẹ nhưng có khả năng tạo ra lực phanh lớn ở các cơ cấu phanh - Lực phanh ở các cơ cấu phanh phải tỉ lệ với lực tác dụng lên bàn đạp phanh - Thoát nhiệt tốt, có khả năng hoạt động liên tục trong khoảng thời gian dài - Dễ kiểm tra, sửa chữa

Diagnosis Technician >> Brake >> Brake System

HỆ THỐNG PHANH THỦY LỰC

@ Các bộ phận chính: - Bàn đạp phanh - Bộ trợ lực phanh - Xy lanh chính - Đường ống dẫn động dầu - Các van phân phối và điều chỉnh lực phanh - Cơ cấu phanh (trống, đĩa)

Diagnosis Technician >> Brake >> Brake System

HỆ THỐNG PHANH THỦY LỰC

@ Bố trí mạch dầu phanh: - Mạch thường (kiểu xe FR) - Mạch chéo (kiểu xe FF) -

Diagnosis Technician >> Brake >> Brake SystemXY LANH CHÍNH

@ Theo chức năng: - Phanh chính - Phanh đậu xe

@ Theo dẫn động phanh:

- Phanh cơ khí - Phanh thủy lực - Phanh khí nén - Phanh thủy khí

Diagnosis Technician >> Brake >> Brake System

Brake System

6. Parking brake 1. Brake pedal 5. Disc brake

2. Brake booster

3. Master cylinder

4. Proportioning valve

(1) Disc brake

(2) Disc brake

(1/1)

Diagnosis Technician >> Brake >> Brake System

Master Cylinder

General & Construction

1.General/2.Construction

Minimum

(7) Fluid level sensor

(5) Rubber piston cups

(6) Reservoir tank

(4) No.2 return spring

(3) No.2 piston

(2) No.1 return spring (1) No.1 piston

(1/3)

Diagnosis Technician >> Brake >> Brake System

Master Cylinder

General & Construction

3. Principles

Principle of the lever Pascal’s law Fulcrum Wheel cylinder 5 cm2 F2 Master cylinder

10 cm2 1000 N 10 cm2

m c 8

m c 0 4

2000 N 20 cm2 2000 N Push rod

400 N F1 Same pressure (2000 kPa) 4000 N

The principle of the lever is applied by the brake pedal as follows.

Operating force: Amount of movement:

F1  A = F2  B  F2 = F1  A B F1: Pedal force b B A B = a = b  b = a  a A B A

F2: Push rod output force a: Amount of movement of pedal edge

A1: Distance from center of brake pedal to b: Amount of movement of push rod fulcrum

B: Distance from push rod to fulcrum

(2/3)

Diagnosis Technician >> Brake >> Brake System

Master Cylinder

General & Construction

4.Types of brake lines

FR vehicle

Front

FF vehicle

Front

(3/3)

Diagnosis Technician >> Brake >> Brake System

Master Cylinder

Operation

1.Normal operation

No.2 return spring No.1 return spring

Compensating port

Inlet port

No.2 piston No.1 piston to front side to Rear side

FF vehicle

No.1 piston cup Stopper bolt

No.2 piston cup

(1/4)

Diagnosis Technician >> Brake >> Brake System

Master Cylinder

Operation

Compensating port

Piston cup

to Front side to Rear side

No.1 piston No.2 piston

Brake pedal depressed (1) Brake pedal depressed (2)

(2/4)

Diagnosis Technician >> Brake >> Brake System

Master Cylinder

Operation

Orifices Inlet port Compensating port

Piston cup

to Front side to Rear side

Brake pedal released (1) Brake pedal released (2)

(3/4)

Diagnosis Technician >> Brake >> Brake System

Master Cylinder

Operation

to Front side to Rear side

No.2 piston No.1 piston

Contact

(4/4)

Diagnosis Technician >> Brake >> Brake System

Master Cylinder

Operation

to Front side to Rear side

No.2 piston No.1 piston

Piston contacts wall

(4/4)

Diagnosis Technician >> Brake >> Brake System

Brake Booster

General & Construction

1.General/ 2.Construction

(12) Constant pressure chamber

(5) Diaphragm

(3) Booster piston Vacuum (13) Check valve (8) Reaction disc

(7) Valve body

Air

(1) Valve operating Brake master cylinder rod

(9) Air cleaner

(10) Body seal (10) Body seal (2) Push rod

(11) Variable pressure chamber (4) Booster body

(6) Diaphragm spring

HINT: Tandem brake booster

(1/1)

Diagnosis Technician >> Brake >> Brake System

Brake Booster

Operation

1.Brakes not applied

Booster piston

Control valve

Valve operating rod Diaphragm spring

Constant pressure chamber Variable pressure chamber Piston Vacuum valve (opened) Control valve

Control valve spring

Passage A Valve body

Constant pressure chamber

Air valve (closed) Valve operating

Air valve return spring Air cleaner element

Passage B Variable pressure chamber

(1/1)

Diagnosis Technician >> Brake >> Brake System

Brake Booster

Operation

2.Brakes applied

Booster piston

Control valve

Valve operating rod Diaphragm spring

Constant pressure chamber Variable pressure chamber

Piston Passage A Vacuum valve (closed)

Constant pressure chamber Control valve Control valve

Control valve spring Control valve spring Air Booster push rod

Air valve (opened) Passage B Valve operating rod Air cleaner element

Passage B Air valve (closed) Variable pressure chamber

(1/1)

Diagnosis Technician >> Brake >> Brake System

Brake Booster

Operation

3.Holding state

Booster piston

Control valve

Valve operating rod Diaphragm spring

Variable pressure chamber Constant pressure chamber

Piston Vacuum valve

Control valve

Control valve spring Constant pressure chamber

Stopped

Valve operating rod

Air valve (closed) Variable pressure chamber

(1/1)

Diagnosis Technician >> Brake >> Brake System

Brake Booster

Operation

4.Maximum boost

Booster piston

Control valve

Valve operating rod Diaphragm spring

Constant pressure chamber Variable pressure chamber

Piston Vacuum valve Constant pressure chamber

Control valve

Control valve spring Booster push rod Air

Air valve (opened)

Valve operating rod

Variable pressure chamber

(1/1)

Diagnosis Technician >> Brake >> Brake System

Brake Booster

Operation

Booster piston

5.Non-vacuum condition

Control valve

Valve operating rod Diaphragm spring

Constant pressure chamber Variable pressure chamber

Piston Vacuum valve Constant pressure chamber

Control valve

Valve body Booster push rod

Air valve Valve operating rod

Valve stopper key

Reaction disc Variable pressure chamber

(1/1)

Diagnosis Technician >> Brake >> Brake System

Brake Booster

Reaction mechanism

1.General/2.Operation

Valve body

Air valve Booster push rod

Reaction disc

80 N (to Valve body)

100 N 20 N (to Air valve)

1cm2 (20N)

4cm2 (80N)

(1/1)

Diagnosis Technician >> Brake >> Brake System

Brake Booster

Gap Adjustment of Push Rod

Choke applied

SST

Thickness gauge

SST

STT 09737-00010

BRAKE BOOSTER ADJUSTMENT •Thickness Gauge(0.2mm or 0.008inch) and Special Service Tool(SST 09737- 00010)are required to check and adjust the push rod length.

• See Repair Manual for details.

Accessory tool

(1/1)

Diagnosis Technician >> Brake >> Brake System

Brake Booster

Function Check

to Intake manifold Airtightness function cheek Atmospheric pressure

Atmospheric pressure

Operating cheek

to Intake manifold Atmospheric pressure

Vacuum

Vacuum tightness function cheek

to Intake manifold Atmospheric pressure

Vacuum

(1/1)

Diagnosis Technician >> Brake >> Brake System

Brake Booster

Function Check

1.Airtightness function check

to Intake manifold Airtightness function cheek Atmospheric pressure

Atmospheric pressure

Operating cheek

to Intake manifold Atmospheric pressure

Vacuum

Vacuum tightness function cheek

to Intake manifold Atmospheric pressure

Vacuum

(1/1)

Diagnosis Technician >> Brake >> Brake System

Brake Booster

Function Check

2.Operation check

to Intake manifold Airtightness function cheek Atmospheric pressure

Atmospheric pressure

Operating cheek

to Intake manifold Atmospheric pressure

Vacuum

Vacuum tightness function cheek

to Intake manifold Atmospheric pressure

Vacuum

(1/1)

Diagnosis Technician >> Brake >> Brake System

Brake Booster

Function Check

to Intake manifold

3.Load airtightness function check

Airtightness function cheek Atmospheric pressure

Atmospheric pressure

Operating cheek

to Intake manifold Atmospheric pressure

Vacuum

Vacuum tightness function cheek

to Intake manifold Atmospheric pressure

Vacuum

(1/1)

Diagnosis Technician >> Brake >> Brake System

Proportioning Valve

General & Construction

1.General/2.Construction

(a)

(b)

Desired curve-line of braking force

Contact

Rear wheel braking fore

with P valve

Front wheel braking force

(4) Compression spring

(5) Cylinder cup

Front

(3) Valve seal

(2) Piston

(1) Valve body

(1/1)

Diagnosis Technician >> Brake >> Brake System

Proportioning Valve

Operation

Cylinder cup

from Master cylinder

Piston

r e d n i l y c l e e h w

Split point

r a e R

e r u s s e r p

Master cylinder pressure

Spring

to Rear wheel cylinders

Master cylinder hydraulic pressure

Master cylinder hydraulic pressure Force by the difference in the pressure reception surface area

(1/1)

Diagnosis Technician >> Brake >> Brake System

Proportioning Valve

Operation

1. Operation up to the split point

Cylinder cup

from Master cylinder

Piston

r e d n i l y c l e e h w

Split point

r a e R

e r u s s e r p

Master cylinder pressure

Spring

to Rear wheel cylinders

Master cylinder hydraulic pressure

Force by the difference in the pressure reception surface area

Spring force

Force by the difference in the pressure reception surface area

(1/1)

Diagnosis Technician >> Brake >> Brake System

Proportioning Valve

Operation

2.Operation of the split point

Cylinder cup

in Contact

from Master cylinder

Piston

r e d n i l y c l e e h w

Split point

r a e R

e r u s s e r p

Master cylinder pressure

Spring

to Rear wheel cylinders

Master cylinder hydraulic pressure

Master cylinder hydraulic pressure Force by the difference in the pressure reception surface area

Spring force

Force by the difference in the pressure reception surface area

(1/1)

Diagnosis Technician >> Brake >> Brake System

Proportioning Valve

Operation

3.Operation after the split point

Cylinder cup

from Master cylinder

Piston

r e d n i l y c l e e h w

Split point

r a e R

e r u s s e r p

Master cylinder pressure

to Rear wheel cylinders

Spring

Repeating

in Contact

Piston

(1/1)

Diagnosis Technician >> Brake >> Brake System

Proportioning Valve

Operation

4.Operation when the pedal is released

Cylinder cup

from Master cylinder

Piston

to Rear wheel cylinders

Spring

(1/1)

Diagnosis Technician >> Brake >> Brake System

Proportioning Valve

Types of P Valve

Dual P valve

P & Bypass valve

Master cylinder

1.Dual P Valve/ 2.Proportioning & Bypass Valve (P & BV)

Dual P.valve

P & BV

Air chamber

Passage (opened)

Spring

Piston

Piston No.1

Piston No.2

Cylinder cup

Spring

Front

(1/2)

Diagnosis Technician >> Brake >> Brake System

Proportioning Valve

Types of P Valve

LSPV

3. Load Sensing Proportioning Valve (LSPV)

LSPV

Control the effectiveness

Out line

Split points

e r u s s e r p

l y l

u l

h .

V e

Cylinder cup

to Rear wheel cylinder

n l o

h i

V e

from Master cylinder

. r d y h r e d n i l y c l e e h w

Piston

r a e R

Valve seal

Master cylinder (front wheel cylinder) hydr. pressure

Valve body

Extends

Load-sensing spring

Cross section

(2/2)

Diagnosis Technician >> Brake >> Brake System

Foot Brake

Disc Brake

1.Construction/ 2.Operation

Before operation

(1) Disc brake caliper

(5) Fluid (4) Piston

(2) Disc brake pad

(3) Disc brake rotor

During operation

(1/6)

Diagnosis Technician >> Brake >> Brake System

Foot Brake

Disc Brake

3.Brake Adjustment

Piston seal changes shape as piston moves.

Piston seal returns piston by amount of its deformation.

Clearance

Disc brake caliper

Piston

Disc brake pad

Amount or return

Amount of deformation

Disc brake rotor

Brakes applied

Brakes released

(2/6)

Diagnosis Technician >> Brake >> Brake System

Foot Brake

Disc Brake

4.Decrease in brake fluid

Reservoir tank

Piston

Master cylinder

Disc brake pad

Brakes pad wear

After pad wear

(3/6)

Diagnosis Technician >> Brake >> Brake System

Foot Brake

Disc Brake

5.Pad wear indicator

Direction of disc brake rotor rotation

Pad wear indicator

Backing plate

Disc brake pad

Anti-squeal shim

Before pad wear

After pad wear

Inner pad

Pad wear indicator

to ECU

ECU

Clip

Pad wear indicator

Before pad wear

After pad wear

(4/6)

Diagnosis Technician >> Brake >> Brake System

Foot Brake

Disc Brake

6.Types of disc brake caliper

Fixed caliper type

Floating caliper type

Hydraulic pressure

Disc brake caliper

Torque plate

Disc brake pads

Disc brake rotor

Steering knuckle (Fixed)

PD type

AD type

FS type

Bolt

Torque plate

Inner pad

Disc brake caliper

Bolt

Disc brake caliper

Torque plate

Bolt

(5/6)

Diagnosis Technician >> Brake >> Brake System

Foot Brake

Disc Brake

7.Types of disc brake rotor

with Drum type

Solid type

Ventilated type

HINT: Fading

(6/6)

Diagnosis Technician >> Brake >> Brake System

Foot Brake

Drum Brake

1.Construction/ 2.Operation

(6) Piston

(7) Piston cup

(1) Wheel cylinder

(5) Brake drum

(2) Brake shoe

(3) Brake lining

(4) Return spring

(1/4)

Diagnosis Technician >> Brake >> Brake System

Foot Brake

Drum Brake

3.Leading shoe and trailing shoe

Wheel cylinder

Direction of drum rotation

Self-energing function

Leading shoe

Trailing shoe

(2/4)

Diagnosis Technician >> Brake >> Brake System

Foot Brake

Drum Brake

4.Types of the drum brake

Fixed wheel cylinder

Fixed anchor

Two-Leading type

Leading-and-trailing type

Fixed wheel cylinder

Adjusting cylinder

Uni-servo type

Duo-servo type

Backward

Forward

Leading shoe

Trailing shoe

(3/4)

Diagnosis Technician >> Brake >> Brake System

Foot Brake

Drum Brake

Fixed wheel cylinder

Fixed anchor

Two-Leading type

Leading-and-trailing type

Fixed wheel cylinder

Adjusting cylinder

Uni-servo type

Duo-servo type

Backward

Forward

Leading shoe

Trailing shoe

(3/4)

Diagnosis Technician >> Brake >> Brake System

Foot Brake

Drum Brake

5.Clearance Adjustment

(1) Auto adjustment type

(2) Manual adjustment type

HINT: Brake Pedal Height Adjustment

(4/4)

Diagnosis Technician >> Brake >> Brake System

Foot Brake

Drum Brake

Adjust lever shoe lever Adjustor

Adjust lever Gap is larger Adjustor

Brake shoe

Adjust lever

Adjustor Drum

Gap between shoe and drum is larger

The adjust lever turns the adjustor

(4/4)

Diagnosis Technician >> Brake >> Brake System

Foot Brake

Drum Brake

Expand

Contract

(4/4)

Diagnosis Technician >> Brake >> Brake System

Parking Brake

Types of Parking Brake Lever

1.Lever type/ 2.Stick type/ 3.Pedal type

Lever type Stick type Pedal type

Release lever

Parking pedal

Lock

Release

HINT: Parking Brake Lever Travel Adjustment

(1/1)

Diagnosis Technician >> Brake >> Brake System

Parking Brake

Types of Parking Brake Body

Drum brake type Disc brake type

Brake shoe Brake shoe Shoe lever Piston

Parking brake cable

Disc brake pad Parking brake cable Shoe lever

Devoted parking brake type Center brake type

Shoe lever

Brake shoe

Parking brake cable Disc brake pad

(1/1)

Diagnosis Technician >> Brake >> Brake System

Parking Brake

Types of Parking Brake Body

1.Foot brake sharing type

Drum brake type Disc brake type

Brake shoe Brake shoe Shoe lever Piston

Parking brake cable

Disc brake pad Parking brake cable Shoe lever

Devoted parking brake type Center brake type

Shoe lever

Brake shoe

Parking brake cable Disc brake pad

(1/1)

Diagnosis Technician >> Brake >> Brake System

Parking Brake

Types of Parking Brake Body

2.Devoted parking brake type

Drum brake type Disc brake type

Brake shoe Brake shoe Shoe lever Piston

Parking brake cable

Disc brake pad Parking brake cable Shoe lever

Devoted parking brake type Center brake type

Shoe lever

Brake shoe

Parking brake cable Disc brake pad

(1/1)

Diagnosis Technician >> Brake >> Brake System

Parking Brake

Types of Parking Brake Body

3.Center brake type

Drum brake type Disc brake type

Brake shoe Brake shoe Shoe lever Piston

Parking brake cable

Disc brake pad Parking brake cable Shoe lever

Devoted parking brake type Center brake type

Shoe lever

Brake shoe

Parking brake cable Disc brake pad

(1/1)

Diagnosis Technician >> Brake >> Brake System

Brake Booster

Tandem Brake Booster

No.2 piston Intake manifold No.1 piston

Air

Variable pressure chamber

Constant pressure chamber

(1/1)

Diagnosis Technician >> Brake >> Brake System

Brake Booster

Fading

0.6

0.5 0.4

0.3

0.2

)  ( n o i t c i r f t n e i c i f f e o C

0.1

0 500 200 300 400 100

Temperature ( C)

(1/1)

Diagnosis Technician >> Brake >> Brake System

Foot Brake

Brake Pedal Height Adjustment

Pedal height Pedal freeplay

Adjusting point

Lock nut

Push rod

(1/1)

Diagnosis Technician >> Brake >> Brake System

Parking Brake

Parking Brake Lever Travel Adjustment

Lock nut

Lever type

Adjusting nut

Stick type

Adjusting nut

Lock nut

Adjusting nut

Lock nut

(1/1)