What Causes A Flexplate To Crack

A cracked flexplate is almost always a sign of other problems. If not properly diagnosed it will occur again and often damage to the transmission may follow.

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The flexplate takes the place of the flywheel on automatic transmission vehicles. It bolts to the end of the crankshaft and attaches to the torque converter. There is also a large gear attached, used by the starter to crank the engine. Because perfect alignment of the engine and transmission are not possible, the flexplate can absorb the minute misalignment.

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As misalignment increases, the flexplate flexes more. This continual flexing eventually causes the metal to fatigue and the flexplate cracks. Misalignment should be less than .008 of an inch and the less the better. When the engine and transmission are manufactured, holes are drilled for bolts to attach them to each other. These holes are larger than the attaching bolts and do not align the two components. Precision dowel pins, that fit very tightly, hold the engine and transmission in alignment.

The dowel pins must be present to align the engine and transmission

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When engines and transmissions are serviced or replaced, it is possible to omit these dowel pins. Sometimes they are left out and misalignment results. Other times, bolts are left out, improperly tightened, or foreign objects get caught between the engine and transmission, such as wires. When this occurs the engine/transmission alignment is thrown off and excessive flexing occurs in the flexplate.

There has been instances where engines are not manufactured properly

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General Motors had problems with this on their 3.8L engines several years ago. The bolt pattern and dowel pins may be drilled improperly. When this occurs the vehicle is likely to have continued problems with flexplate breakage. A dial indicator may be used to check symmetrically designed engines. On non-symmetric engines, special jigs and complex measurements may be needed.

The more excessive the misalignment, the more frequent problems occur

Slight misalignment may only cause a single flexplate to break in the life of the vehicle. More severe misalignment can break a flexplate in 15,000 to 30,000 miles. Excessive crankshaft flange run-out or end plate can also cause flexplate cracking. This may occur in worn engines or engine that have been poorly rebuilt. An engine, transmission or torque converter that has been dropped may also have damage that will cause misalignment.

When a running engine ingest water or coolant, the crankshaft may be bent. Liquids will not compress and immense force is placed on the crankshaft and rods. This sometimes happens with a leaking intake manifold or driving on a flooded street. The bent crankshaft will have run-out at the flange and may have continued problems with flexplate cracking.

The same things that cause the flexplate to crack can also cause transmission problems. Damaged and leaking front seals and front transmission pumps are common symptoms.

When a flexplate cracks, it often produces a loud knocking noise as it rotates. The sound is very similar to a bad engine rod and is often misdiagnosed. Removing the bolts to the torque converter and sliding it back into the transmission will often reveal the real problem.

When a flexplate breaks, it is important to find the cause

Simply replacing the flexplate will result in recurrence. Trying to install a heavier duty flexplate will normally pass the problem to the transmission. Correcting the cause of the misalignment is the only repair that will give permanent results.

This article comes from AGCOAUTO edit released

 

Axial Vane Hydraulic Motors

1For robotics and other such applications where precise, repeatable positioning is paramount, our Axial Vane motors warrant your consideration. Available in both Servo and Industrial grades, they deliver these characteristics:

Axial Vane Cutaway Diagram

2

Hold position repeatedly and accurately

Mechanically “stiff” when locked

Smooth starts and slow-speed operation

Extremely long life — relatively few wearing parts

High starting torque — 97%

Manifold port capability

A host of options are also available:

Choice of output shafts

Dual relief valves, motor mounted

Rotor shaft extensions

SAE B flange mount

Tach generator packages

Brakes, rear mounted

This article comes from Von Ruden editor released

 

Variable displacement oil pump helps Chevrolet Cruze hit 40 mpg

20150424Back when a greenhouse was a structure used to grow plants in cold weather, an oil pump was just a non-descript but necessary device to keep metal engine parts well lubricated. As engineers work to meet the 35.5 mile per gallon Corporate Average Fuel Economy (CAFE) standard, the lowly oil pump has become one of many places where they can find incremental improvements in efficiency.

The turbocharged 1.4-liter inline-four in the 2011 Chevrolet Cruze features a variable displacement oil pump that helps reduce the parasitic losses that increase fuel consumption. While an engine always needs oil, the amount depends on the speed and load at any given time. Traditional oil pumps are driven off the engine and sized for the worst case conditions the engine is expected to experience. As a result, they typically move much more oil than the engine needs, and the excess is dumped back to the oil pan through a bypass.

The variable displacement pump on the Cruze engine is electronically controlled so that it only sends out as much oil as the engine needs. Spring-loaded vanes sit in slots in the drive hub of the pump as it rotates in an off-center housing. As the hub rotates from the pump inlet to the outlet, the vanes are pushed in and the cavity between them gets smaller causing the oil pressure to rise. A larger difference between the inlet and outlet volume means more oil pressure and flow.

The outer housing of the General Motors pump is mounted on a pivot, which allows the center of the housing to move closer to the center of the hub. This reduces the volume change in the pump and the resulting oil flow.

According to GM spokesman Tom Read, the efficiency improvement attributable directly to the new oil pump is “less than one percent.” However, when added together with other, similar features like thermostatic shutters that close off the grille at higher speeds and the electric power assisted steering, it adds up to a car that gets an EPA rating of 40 miles per gallon on the highway.
This article comes from General Motors editor released

 

Vane For Engine Camshaft Phaser

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Vane type phaser system deflected the blade through the internal hydraulic pressure to achieve stepless adjustment of the phase angle, phase adjustment range and response speed of a vry substantial improvement. In addition,the structure of the program vane type phaser compact system, whether it is the recent camshaft or the exhaust camshaft can easily be arranged. Vanes are the main part of the camshaft, their quality is also crucial.

Parameter:

1. Material : 100Cr6

2. Hardness : HVI 750+140

3. Precision :0.003~0.005mm or custom-made is acceptable

4. Surface Roughness: Ra<0.2

Thickness Width Length Radius
3,000 18.6 23 Flat

This article comes from ZT INTERNATIONAL editor released

How Car Steering Works?

Power Steering
There are a couple of key components in power steering in addition to the rack-and-pinion or recirculating-ball mechanism.
Pump
The hydraulic power for the steering is provided by a rotary-vane pump (see diagram below). This pump is driven by the car’s engine via a belt and pulley. It contains a set of retractable vanes that spin inside an oval chamber.
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As the vanes spin, they pull hydraulic fluid from the return line at low pressure and force it into the outlet at high pressure. The amount of flow provided by the pump depends on the car’s engine speed. The pump must be designed to provide adequate flow when the engine is idling. As a result, the pump moves much more fluid than necessary when the engine is running at faster speeds.
The pump contains a pressure-relief valve to make sure that the pressure does not get too high, especially at high engine speeds when so much fluid is being pumped.
Rotary Valve
A power-steering system should assist the driver only when he is exerting force on the steering wheel (such as when starting a turn). When the driver is not exerting force (such as when driving in a straight line), the system shouldn’t provide any assist. The device that senses the force on the steering wheel is called the rotary valve.
The key to the rotary valve is a torsion bar. The torsion bar is a thin rod of metal that twists when torque is applied to it. The top of the bar is connected to the steering wheel, and the bottom of the bar is connected to the pinion or worm gear (which turns the wheels), so the amount of torque in the torsion bar is equal to the amount of torque the driver is using to turn the wheels. The more torque the driver uses to turn the wheels, the more the bar twists.
The input from the steering shaft forms the inner part of a spool-valve assembly. It also connects to the top end of the torsion bar. The bottom of the torsion bar connects to the outer part of the spool valve. The torsion bar also turns the output of the steering gear, connecting to either the pinion gear or the worm gear depending on which type of steering the car has.
Animation showing what happens inside the rotary valve when you first start to turn the steering wheel
As the bar twists, it rotates the inside of the spool valve relative to the outside. Since the inner part of the spool valve is also connected to the steering shaft (and therefore to the steering wheel), the amount of rotation between the inner and outer parts of the spool valve depends on how much torque the driver applies to the steering wheel.
When the steering wheel is not being turned, both hydraulic lines provide the same amount of pressure to the steering gear. But if the spool valve is turned one way or the other, ports open up to provide high-pressure fluid to the appropriate line.
It turns out that this type of power-steering system is pretty inefficient. Let’s take a look at some advances we’ll see in coming years that will help improve efficiency.
This article comes from howstuffworks editor released

Vane pumps for passenger cars

In power steering systems, a pressurised liquid (hydraulic oil) provides assistance to the steering force. The required pressure is produced by the steering pump, usually via a belt drive which is driven directly by the engine. This is where vane pumps come in.
We produce the following types of vane pump: CP 14, CP 1, FP 2, FP 4, FP 6.
Owing to their design, vane pumps have an oil flow rate which is proportional to the drive speed. As the pumps are usually driven by the engine, their speed varies depending on the driving situation. However, power steering systems require a constant flow of oil. For this reason, power steering pumps have a bypass control enabling them to provide a constant volume flow.

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Characteristics of the different types
CP 14
Standardised mounting
Belt driven
Constant, falling or stepped falling curve possible
CP 1
Modular design
Multiple mounting options
Belt driven
Constant, drooping or stepped drooping curve possible
FP 2
Standardised mounting (VDA)
Belt driven
Constant, drooping or stepped drooping characteristic possible
For low hydraulic requirements
FP 4
Standardised mounting (VDA)
Belt driven
Constant, drooping or stepped drooping characteristic possible
Energy-saving pump with ECO Valve possible
Fitted oil reservoir possible
FP 6
For higher hydraulic requirements
Standardised mounting (VDA)
Belt driven
Constant, drooping or stepped drooping characteristic possible
Energy-saving pump with ECO Valve possible
Fitted oil reservoir possible
This article comes from BOSCH Technik Leben editor released

High speed steel production process

High speed steel heat treatment process is more complex, must be quenched and tempered and a series of processes. Quenching due to its poor thermal conductivity generally divided into two phases. First at 800 ~ 850 ℃ preheating (in order to avoid large thermal stress), then rapidly heated to the quenching temperature 1190 ~ 1290 ℃ (different grades of actual use temperature difference), the oil cooling or air cooling, or cooling the inflatable body. Factories are using salt furnace heating, vacuum furnaces are now quite extensive. Due to the internal organization also keep part (about 30%) did not change after quenching residual austenite into martensite, affecting the performance of high speed steel. To make the residual austenite, to further improve the hardness and wear resistance, generally 2 to 3 times a tempering, tempering temperature 560 ℃, each incubated for 1 hour.

Manufacturing methods: usually electric production, have been used in the production of high-speed steel powder metallurgy method, so that was a very fine carbide particles uniformly distributed in the matrix, improving the service life.

Uses: used in the manufacture of various cutting tools. Such as turning, drilling, hob, machine saw and demanding mold.

History of the development of high speed steel

In 1898, the American Society of Mechanical Engineers and management Taylor (TaylorF.W.) And metallurgists White (WhiteM.) Developed the invention of high speed steel, and made a cutting test system. When they determine high speed steel components for C-0.67%, W-18.91%, Cr-5.47%, Mn-0.11%, V-0.29%, F- margin, and later W18Cr4V composition is very close. High-speed steel cutting tools available 30m / min cutting speed steel, which is several times more efficient than carbon tool steel and alloy tool steel used in the past, for the United States at the time of the machinery industry won a huge economic benefits.

W18Cr4V speed steel thermoplastic bad, because the twist need hot rolling process, and later the successful development of high-speed steel W6Mo5Cr4V2 addition, there W9Mo3Cr4V. Cutting and mechanical properties of these three high-speed steel approximation, called universal.

After the mid-20th century, the rapid development of science and technology, a variety of difficult materials continue to emerge, the performance of general-purpose high-speed steel no longer use, so high speed steel and high speed steel powder metallurgy have appeared, so the performance of high-speed steel cutting tool material has been greatly improved.

Technical parameters of stainless steel

Steel symbol and representation
① chemical element with the international symbols and symbols to represent the country’s chemical composition, using the Arabic alphabet to represent the content:
Such as: China, Russia 12CrNi3
② with a fixed number of digits to represent the steel type series or digital; such as: USA, Japan, 300 series, 400 series, 200 series;
③ composition of the Latin alphabet and the order number, saying only that purpose.
China’s numbering rules
① using element symbols
② use Hanyu Pinyin, open-hearth steel: P, boiling steel: F, killed steel: B, Group A steel: A, T8: Special 8, GCr15: Ball
◆ alloy steel, spring steel, such as: 20CrMnTi 60SiMn, (with a very few that C content)
stainless steel, alloy tool steel (with a few thousandths C content), such as: 1Cr18Ni9 thousandth (ie, 0.1% C), stainless C≤0.08% as 0Cr18Ni9, ultra-low carbon C≤0.03% as 00Cr17Ni13Mo
International Stainless Steel labeling method
American Iron and Steel Institute with three digits to indicate a variety of standard grade stainless steel malleable. Among them:
① austenitic stainless steel 200 and 300 series of numerals, for example, some of the more common austenitic stainless steel is 201, 304, 316 and 310 marks.
② ferritic and martensitic stainless steel 400 series is represented by a number.
③ ferritic stainless steel is marked 430 and 446, 410, 420, and 440C martensitic stainless steel is marked.
④ duplex (austenitic – ferritic), stainless steel, precipitation hardening stainless steel and high alloy iron content of less than 50% usually uses proprietary name or trademark name.
4). Standard classification and grading
4-1 of Classification:
National Standard GB ② ① industry standards YB ③ ④ local standards enterprise standard Q / CB
4-2 Categories:
① ② Packaging Standard Products Standard Method Standard ③ ④ basic standards
4-3 standard level (three points):
Y levels: international advanced level class I: Class H common international level: the advanced level
4-4 GB
GB1220-84 stainless steel rods (I grade) GB4241-84 stainless steel plate welded Park (H level)
GB4356-84 stainless steel plate welded Park (I-level) GB1270-80 stainless steel tubing (I Class)
GB12771-91 stainless steel pipe (Y class) GB3280-84 stainless steel cold (I Class)
GB4237-84 stainless steel hot plate (I grade) GB4239-91 stainless steel cold strip (I Class)

Development of high-viscosity hydraulic rotary gear pump shaft

High viscosity because of the high viscosity of the medium conducting oil pump (high viscosity pump) conveyed, in order to reduce the resistance activity, progress absorbent capacity pump, is necessary for heating the media or insulation. Usually electric heating elements, can heat an average viscous liquid. If the temperature is low volatility and high viscosity liquids transported easily degradation occurs, we recommend using the fluid heating, especially large displacement gear pump. Fluid heating divided internal, external structure.

The so-called built-in refers to the internal gear pump body or cover design suddenly shrunk, external clamp bolt is through the thermal sleeve and pump are coupled together. To the jacket into the steam, oil, cooling water is still, according to the media in detail the circumstances. Built-in together for a higher average transmission fluid temperature requirements, or requirements for the average high temperature liquid cooling applications. When the lack of security or electric heating temperature control less demanding, can be an external structure.

HTF high viscosity gear pump common with straight teeth, helical, herringbone gear, helical gear, involute tooth profile main types of lines and arcs. Usually small gear pump more involute spur gears, gear pumps often used high temperature shifted gear, transport of high viscosity, high-pressure melt the polymer melt pump more involute helical gear. Gear formed integrally with the shaft, its rigidity and higher reliability than a gear with a gear pump shaft is separately manufactured. Foreign low pressure gear pump gear often used a square structure, i.e., the gear tooth width that is the tip diameter. The use of high-viscosity gear pump high pressure applications tooth width less than the diameter of its addendum circle, which is to reduce the radial pressure receiving area of ​​the gear, reducing gears, bearings load.