常见故障分析 Prepared by Rod Erickson, Eaton Corp. Hydraulics Training Center...

常见故障分析常见故障分析

PreparedPrepared by Rod Erickson, Eaton Corp. Hydraulics Training Centerby Rod Erickson, Eaton Corp. Hydraulics Training Center

伊顿转向系统伊顿转向系统

?

如何分析一个故障系统如何分析一个故障系统 ? – ? – 参考手册参考手册 # 7-207# 7-207

转向系统常见故障分析转向系统常见故障分析

C h a r -Ly n n S te e r in g C o n t ro l U n i t

H ous ing

C on tro l S lee ve

C on tro l S poo l

D rive S h a ft

G e ro to r S e t

C en te r ing P in

转向器组成元件

转向器的组成部分转向器的组成部分

Engine PFC Pump

Reservoir

Filter

L

T

R

P

EF

CF

p

LS

1. 1. 检查泵的磨损和故障检查泵的磨损和故障

2. 2. 安全阀失效安全阀失效

3. 3. 油管连接错误油管连接错误4. 4. 如果是负荷传如果是负荷传感系统，确保负荷感系统，确保负荷传感回路畅通或者传感回路畅通或者管径太小管径太小 . . 也不能也不能忽视优先阀的检查忽视优先阀的检查

问题 1 -问题 1 -

转向迟缓，转向困难或者失去转向功能

车辆不能沿直线行走 .

问题 2 -- 偏离问题 2 -- 偏离

问题 2 -- 偏离问题 2 -- 偏离

问题 2 -- 偏离问题 2 -- 偏离

问题 2 -- 偏离问题 2 -- 偏离

问题 2 -- 偏离问题 2 -- 偏离

问题 2 -- 偏离问题 2 -- 偏离

问题 2 -- 偏离问题 2 -- 偏离

问题 2 -- 偏离问题 2 -- 偏离

问题 2 -- 偏离问题 2 -- 偏离

问题 2 -- 偏离问题 2 -- 偏离

问题 2 -- 偏离问题 2 -- 偏离

问题 2 -- 偏离问题 2 -- 偏离

问题 2 -- 偏离问题 2 -- 偏离

问题 2 -- 偏离问题 2 -- 偏离

问题 2 -- 偏离问题 2 -- 偏离

问题 2 -- 偏离问题 2 -- 偏离

问题 2 -- 偏离问题 2 -- 偏离

问题 2 -- 偏离问题 2 -- 偏离

问题 2 -- 偏离问题 2 -- 偏离

问题 2 -- 偏离问题 2 -- 偏离

问题 2 -- 偏离问题 2 -- 偏离

问题 2 -- 偏离问题 2 -- 偏离

问题 2 -- 偏离问题 2 -- 偏离

问题 2 -- 偏离问题 2 -- 偏离

问题 2 -- 偏离问题 2 -- 偏离

问题 2 -- 偏离问题 2 -- 偏离

问题 2 -- 偏离问题 2 -- 偏离

问题 2 -- 偏离问题 2 -- 偏离

问题 2 -- 偏离问题 2 -- 偏离

问题 2 -- 偏离问题 2 -- 偏离

也辆不能沿直线行走 .

问题出在哪里呢问题出在哪里呢 ??

1. 1. 检查气穴检查气穴 , ,

Check for clogged suction strainer or Check for clogged suction strainer or clogged inlet filterclogged inlet filter

Look for a restriction between the Look for a restriction between the inlet and pumpinlet and pump

问题 2 -- 偏离问题 2 -- 偏离

CAVITATIONCAVITATION

CAVITATIONCAVITATION

CAVITATION DAMAGECAVITATION DAMAGE

A e ra t io n o f H y d ra u lic P u m p

A ir

LeakyF itting E rosion

A ir B ubb lesIm p lode

A ir B ubb lesE xpand

2. 2. Air in the system,Air in the system,

Leaky FittingLeaky Fitting.

1. . Check for CavitationCheck for Cavitation

Vehicle will not stay in a straight line.

PROBLEM 2: WANDERPROBLEM 2: WANDER

Vehicle will not stay in a straight line.

2. 2. Air in the system,Air in the system,

Leaky Fitting,. Leaky Fitting,.

Reservoir

Engine PFC Pump

Filter

L

T

R

P

p

4. 4. Loose cylinder pistonLoose cylinder piston

or bending of linkageor bending of linkage

3. 3. Low reservoir Low reservoir

1. 1. Check for CavitationCheck for Cavitation

PROBLEM 2: WANDERPROBLEM 2: WANDER

Vehicle veers slowly in one direction.

PROBLEM 3: DRIFTPROBLEM 3: DRIFT

Vehicle veers slowly in one direction.

PROBLEM 3: DRIFTPROBLEM 3: DRIFT

PROBLEM 3: DRIFTPROBLEM 3: DRIFT

PROBLEM 3: DRIFTPROBLEM 3: DRIFT

PROBLEM 3: DRIFTPROBLEM 3: DRIFT

PROBLEM 3: DRIFTPROBLEM 3: DRIFT

PROBLEM 3: DRIFTPROBLEM 3: DRIFT

PROBLEM 3: DRIFTPROBLEM 3: DRIFT

PROBLEM 3: DRIFTPROBLEM 3: DRIFT

PROBLEM 3: DRIFTPROBLEM 3: DRIFT

PROBLEM 3: DRIFTPROBLEM 3: DRIFT

PROBLEM 3: DRIFTPROBLEM 3: DRIFT

PROBLEM 3: DRIFTPROBLEM 3: DRIFT

PROBLEM 3: DRIFTPROBLEM 3: DRIFT

PROBLEM 3: DRIFTPROBLEM 3: DRIFT

PROBLEM 3: DRIFTPROBLEM 3: DRIFT

PROBLEM 3: DRIFTPROBLEM 3: DRIFT

PROBLEM 3: DRIFTPROBLEM 3: DRIFT

PROBLEM 3: DRIFTPROBLEM 3: DRIFT

PROBLEM 3: DRIFTPROBLEM 3: DRIFT

PROBLEM 3: DRIFTPROBLEM 3: DRIFT

PROBLEM 3: DRIFTPROBLEM 3: DRIFT

PROBLEM 3: DRIFTPROBLEM 3: DRIFT

PROBLEM 3: DRIFTPROBLEM 3: DRIFT

PROBLEM 3: DRIFTPROBLEM 3: DRIFT

1. 1. Single rod end cylinder slowly Single rod end cylinder slowly

extends without turning the extends without turning the

steering wheel.steering wheel.

Note: A small rate of extension may Note: A small rate of extension may

be normal on a closed center system. be normal on a closed center system.

EngineFixed Pump

Reservoir

Filter

L

T

R

P

p

2. 2. Check for worn or damaged Check for worn or damaged

steering linkage.steering linkage.

Vehicle veers slowly in one direction.

Check the linkage

PROBLEM 3: DRIFTPROBLEM 3: DRIFT

A slow movement of the steering wheel fails to cause any movement of the wheels.

Piston Seal Leak

Qi n

Qo u t

Leakage of cylinder piston seals Leakage of cylinder piston seals

or accessory valve between or accessory valve between

cylinder lines or portscylinder lines or ports

PROBLEM 4: SLIPPROBLEM 4: SLIP

Temporary hard steering or hang up:

2. 2. Plugged Orifice or Plugged Orifice or internal reliefinternal relief

EngineFixed Pump

Reservoir

Filter

L

T

R

P

p

10 F

- 40 F

1. 1. Thermal Shock - Thermal Shock - Caused by more than a 50 Caused by more than a 50 F temperature differential F temperature differential

PROBLEM 5: HARD STEERINGPROBLEM 5: HARD STEERING

1. 1. Air in the systemAir in the system

EngineFixed Pump

Reservoir

Filter

L

T

R

P

p

2. . Loose Cylinder PistonLoose Cylinder Piston

3. 3. Thermal ShockThermal Shock

4. 4. Sticking Flow Control Sticking Flow Control Spool. Spool.

PROBLEM 6: ERRATIC STEERINGPROBLEM 6: ERRATIC STEERING

EngineFixed Pump

Reservoir

Filter

L

T

R

P

p

Air in the system,Air in the system,

most likely in the most likely in the

cylinder or linescylinder or lines

PROBLEM 7: SPONGY STEERINGPROBLEM 7: SPONGY STEERING

Steering wheel turns freely with no feeling of pressure Steering wheel turns freely with no feeling of pressure and no action on the steered wheels and no action on the steered wheels

EngineFixed Pump

Reservoir

Filter

L

T

R

P

p

PROBLEM 8 - FREE WHEELINGPROBLEM 8 - FREE WHEELING

EngineFixed Pump

Reservoir

Filter

L

T

R

P

p

PROBLEM 8 - FREE WHEELINGPROBLEM 8 - FREE WHEELING

Steering wheel turns freely with no feeling of pressure Steering wheel turns freely with no feeling of pressure and no action on the steered wheels and no action on the steered wheels

EngineFixed Pump

Reservoir

Filter

L

T

R

P

p

Steering wheel turns freely with no feeling of pressure Steering wheel turns freely with no feeling of pressure and no action on the steered wheels and no action on the steered wheels

PROBLEM 8 - FREE WHEELINGPROBLEM 8 - FREE WHEELING

EngineFixed Pump

Reservoir

Filter

L

T

R

P

p

Steering wheel turns freely with no feeling of pressure Steering wheel turns freely with no feeling of pressure and no action on the steered wheels and no action on the steered wheels

PROBLEM 8 - FREE WHEELINGPROBLEM 8 - FREE WHEELING

EngineFixed Pump

Reservoir

Filter

L

T

R

P

p

Steering wheel turns freely with no feeling of pressure Steering wheel turns freely with no feeling of pressure and no action on the steered wheels and no action on the steered wheels

PROBLEM 8 - FREE WHEELINGPROBLEM 8 - FREE WHEELING

EngineFixed Pump

Reservoir

Filter

L

T

R

P

p

Steering wheel turns freely with no feeling of pressure Steering wheel turns freely with no feeling of pressure and no action on the steered wheels and no action on the steered wheels

PROBLEM 8 - FREE WHEELINGPROBLEM 8 - FREE WHEELING

EngineFixed Pump

Reservoir

Filter

L

T

R

P

p

Steering wheel turns freely with no feeling of pressure Steering wheel turns freely with no feeling of pressure and no action on the steered wheels and no action on the steered wheels

PROBLEM 8 - FREE WHEELINGPROBLEM 8 - FREE WHEELING

EngineFixed Pump

Reservoir

Filter

L

T

R

P

p

Steering wheel turns freely with no feeling of pressure Steering wheel turns freely with no feeling of pressure and no action on the steered wheels and no action on the steered wheels

PROBLEM 8 - FREE WHEELINGPROBLEM 8 - FREE WHEELING

EngineFixed Pump

Reservoir

Filter

L

T

R

P

p

Steering wheel turns freely with no feeling of pressure Steering wheel turns freely with no feeling of pressure and no action on the steered wheels and no action on the steered wheels

PROBLEM 8 - FREE WHEELINGPROBLEM 8 - FREE WHEELING

EngineFixed Pump

Reservoir

Filter

L

T

R

P

p

Steering wheel turns freely with no feeling of pressure Steering wheel turns freely with no feeling of pressure and no action on the steered wheels and no action on the steered wheels

PROBLEM 8 - FREE WHEELINGPROBLEM 8 - FREE WHEELING

EngineFixed Pump

Reservoir

Filter

L

T

R

P

p

1. 1. Steering column upper Steering column upper shaft is loose or damagedshaft is loose or damaged

2. 2. Lower splines of column may Lower splines of column may be disengaged or brokenbe disengaged or broken

3. 3. Lack of oil to steering Lack of oil to steering unit or meter section:unit or meter section:

Steering wheel turns freely with no feeling of pressure Steering wheel turns freely with no feeling of pressure and no action on the steered wheels and no action on the steered wheels

PROBLEM 8 - FREE WHEELINGPROBLEM 8 - FREE WHEELING

Steering wheel turns with slight resistance but results in Steering wheel turns with slight resistance but results in little or no steered wheel action.little or no steered wheel action.

EngineFixed Pump

Reservoir

Filter

L

T

R

P

p

1. 1. Leaking crossover relief Leaking crossover relief valve or anti-cavitation valve valve or anti-cavitation valve

in the cylinder linesin the cylinder lines..

2. 2. Piston seal is Piston seal is blown outblown out

PROBLEM 9 - FREE WHEELINGPROBLEM 9 - FREE WHEELING

EngineFixed Pump

Reservoir

Filter

L

T

R

P

p

1. 1. Loose steering wheel Loose steering wheel nut. nut.

2. 2. Steering column shaft worn or Steering column shaft worn or damageddamaged

PROBLEM 10 - EXCESSIVE PLAYPROBLEM 10 - EXCESSIVE PLAY

EngineFixed Pump

Reservoir

Filter

L

T

R

P

p

PROBLEM 11 - EXCERSSIVE PLAYPROBLEM 11 - EXCERSSIVE PLAY

2. 2. Leaky CylinderLeaky Cylinder

1. 1. Broken or worn Broken or worn linkage between linkage between

cylinder and steered cylinder and steered wheelswheels

PROBLEM 11 - EXCERSSIVE PLAYPROBLEM 11 - EXCERSSIVE PLAY

EngineFixed Pump

Reservoir

Filter

L

T

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P

p

2. 2. High back pressure in the tankHigh back pressure in the tank

line can cause slow return to center, line can cause slow return to center,

back pressure should not exceed back pressure should not exceed

300 PSI300 PSI

1. 1. Binding or misalignment in Binding or misalignment in

steering column or splined inputsteering column or splined input

connectionconnection

3. 3. Large particles can cause bindingLarge particles can cause binding

between the spool and sleeve.between the spool and sleeve.

PROBLEM 12 -PROBLEM 12 -

BINDING OR POOR CENTERING OF STEERING WHEEL

3. 3. Broken PinBroken Pin

2. 2. Severe wearSevere wear

11. . Large particles in the Large particles in the

meter sectionmeter section

4. 4. Thermal shock (50 degree F Temperature differential)Thermal shock (50 degree F Temperature differential)

PROBLEM 13 - STEERING UNIT LOCKS UPPROBLEM 13 - STEERING UNIT LOCKS UP

L

T

R

P

Problem - May turn by itself.

Parts are assembled wrong.Parts are assembled wrong.

Steering unit is improperly timedSteering unit is improperly timed

PROBLEM 14 - STEERING WHEEL OSCILLATESPROBLEM 14 - STEERING WHEEL OSCILLATES

L

T

R

P

Lines are connected to Lines are connected to

the wrong cylinder portsthe wrong cylinder ports

Left turnLeft turn

PROBLEM 15 - TURNS THE WRONG DIRECTIONPROBLEM 15 - TURNS THE WRONG DIRECTION

L

T

R

P

PROBLEM 16 - STEERING WHEEL KICKPROBLEM 16 - STEERING WHEEL KICK

L

T

R

P

PROBLEM 16 - STEERING WHEEL KICK PROBLEM 16 - STEERING WHEEL KICK

L

T

R

P

What can you do to

help prevent steering

kick?

PROBLEM 16 - STEERING WHEEL KICK PROBLEM 16 - STEERING WHEEL KICK

If steering wheel kicks at the start If steering wheel kicks at the start of steeringof steering - - Install Inlet CheckInstall Inlet Check ValveValve - - It prevents oil from returning through the steering unit when pressure on the cylinder side is greater than pressure on the inlet side to prevent steering wheel kick.

PROBLEM 16 - STEERING WHEEL KICKPROBLEM 16 - STEERING WHEEL KICK

Engine PFC Pump

Reservoir

Filter

L

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EF

CF

p

LS

Hoses jump, severe vibrationHoses jump, severe vibration

in hydraulic system, noise, in hydraulic system, noise,

vehicle vibration, when steeringvehicle vibration, when steering

is activated.is activated.

1. 1. Air in the linesAir in the lines

PROBLEM 17- INSTABILITY PROBLEM 17- INSTABILITY

LOAD SENSING SYSTEMS

Engine PFC Pump

Reservoir

Filter

L

T

R

P

EF

CF

p

LS

Hoses jump, severe vibrationHoses jump, severe vibration

in hydraulic system, noise, in hydraulic system, noise,

vehicle vibration, when steeringvehicle vibration, when steering

is activated.is activated.

1. 1. Air in the linesAir in the lines

2. 2. Harmonic system - Add hose Harmonic system - Add hose

or accumulatoror accumulator

3. 3. Relief valve - Pump relief Relief valve - Pump relief

should be 300 PSI aboveshould be 300 PSI above

priority reliefpriority relief..

4. 4. Load sensing pump may Load sensing pump may

have a sticky compensatorhave a sticky compensator

PROBLEM 17- INSTABILITY PROBLEM 17- INSTABILITY

LOAD SENSING SYSTEMS

The End

The End