User:Kolektor COR pump

= COR pump technology =

1. Introduction
Pumps are generally divided into hydrostatic and hydrodynamic. Hydro dynamical pumps operate on a hydrodynamic physical process in which there are pressure and energy changes in the proportional square of the speed of the rotor. Their characteristic is that there is no sealing function between the suction and the pressure side. Hydrodynamic pumps ensure continuous pressure without the pulsation phenomena.Pumps are axial, radial and diagonal.Hydrodynamic pumps (also known as positive displacement pumps) increase and decrease volume of the pump chamber during operating cycle.

Target properties of hydrostatic pumps are:

Stable efficiency in wide working area (over different flow or pressure),


 * low noise emissions,
 * high reliability at high mechanical and/or thermal loads,
 * small size and weight, low price, easy assembly and servicing,
 * possibility of integration with control devices  (pressure, flow, temperature sensors),
 * possibility of operating over wide viscosity range of liquids and
 * low pulsation of pressure and flow.

The trends in the development of the positive displacement pumps are oriented towards achieving higher pressures and rotating speed of products. Less material consumption and simplified production technology solutions are motivations from the design and manufacturing aspect. Hydrostatic pumps are classified into two larger groups - to pumps with a translatory motion of liquid displacement element, and to pumps with a rotating element (shaft).

The element that performs the translatory motion is usually a piston. Such group of pumps is called piston pumps. The group of pumps in which the liquid displaces the rotating element (rotor) is further divided into gear pumps, screws and vane pumps.

In the automotive industry, PD (positive displacement) pumps are used in numerous applications. The advantage of the axial piston pumps is high pressures achieved and the ability to adapt the displacement volume of liquid. Their disadvantage is complex assembly and consequently high production cost. These pumps also used in climate compressors. Characteristics of the vane pumps are compact design, low-pressure pulsations and sensitivity to rapid pressure changes. Vane pumps are installed in the hydraulic power systems and also used as delivery pumps in the common rail fuel injection system In addition to the vane pumps, gear pumps (external and ge-rotor) are used as fuel delivery pumps for common rails system. As high-pressure pumps, radial piston pumps are used in these systems. As fuel delivery pumps go, also roller-cell, Ge-rotor and turbine pump technology is used.

The two most common pump types in automotive transmissions are the gear- and the vane type. This is because of their rigid and inexpensive design. Unlike the gear pump, the vane type can be made with a variable displacement. This means that the vane pump can vary its output flow, while the gear pump displaces a fixed quantity of fluid per revolution. Since the output is positive for a given operating speed, it is not significantly affected by resistance to flow. Instead, the resistance to flow will dictate the pump output pressure. This is the most important characteristic of a positive displacement pump.

The most widely used positive displacement pump is the gear pump. This is largely due to thesimplicity and robustness of its design. There are two basic types of gear pumps:


 * external gear pump (most common type is spur gear pump)


 * internal gear pump (most common type is Gerotor pump).

The gear type pump has several advantages over the vane pump. These advantages are: higheroutput flow, higher speed capability, higher mechanical efficiency, simpler serviceability, greater tolerance to contamination, and last but not least, lower cost. The vane pump is comparable to the gear pump in terms of output pressure level. However, a vane pump has the advantage of higher volumetric efficiency and the ability of a variable displacement design compared to the gear pump.

2. COR Pump technology – made by injection molding
To save weight and meet modern fuel efficiency standards, automotive engineers have learned to substitute plastic materials for metal wherever possible. Even beyond weight savings, versatile plastics offer numerous manufacturing efficiencies.

Compared to machining or die-casting, rapid, cost-saving material processing methods such as short cycle-time injection molding allow high-volume production, often with no secondary steps. Nonetheless, many automotive parts are made from metal. The applicative temperature and dimensional demands are often the deciding factors in terms of material chosen.

However, new developments in high dimensionally and thermally stable polymer resins and molding tooling techniques have shifted that balance, expanding the range of applications for which polymer materials may be used. One example of an automotive component now amenable to be made from high dimensionally and thermally stable polymer material is the COR pump technology where most important and demanding components are made with injection molding production process.

The COR pump is a new pump technology in group of positive displacement pumps. Basic pumping idea came from the axial piston pump family.

The COR technology consist of 2 pumping principles: DoppelRotor (COR-DRP) and Tumbling multi chamber (COR-TMC).

The COR pump consists of 4 pieces of which 2 are rotating. No valves are needed. Most of the torque is  converted into useful work as only one of the two rotating pieces is driven. Due to the design concept, the  second one only needs torque to overcome its friction. The fluid is transferred through the center of the pump and transferred with the help of moving cavities and centrifugal force to the outlet on the periphery. Pressures of up to 50 bar (725 PSI) as well as different fluids like water, oil and chemicals with higher viscosity are possible.

Basically, the pump design is based on 3-dimensional trochoid gear shape with function of pulsating chambers for volume displacement. There are different shape and designs possible used in pressure pump, compressor or vacuum pump.

The operating principle is based on the formation of the separate chambers, closed by two gearing topographies. When rotated, the chambers open (grow) and close (shrink) simultaneously and control fluid displacement precisely. Connection of the pulsating chambers with suitable control openings (with matching contours) results in the displacement effect.

One of basic outputs of this pump design is pressure separation effect. The enveloping part (pump housing) also serves as a separating element between the pressure side and the suction side.

COR-DRP is analogous to a ge-rotor pump, as the fluid between the teeth is displaced by different rotational speeds of the rotors.

COR-TMC is analogous to an axial piston pump, as the fluid is displaced by opening and closing of chambers.

The COR pump consists of a pump stator with a 3D inner gear shape with n teeth and a pump rotor with n+1 teeth, which fits on the stator shape under a certain angle. The gear shape (teeth) is arranged axially,and the shape of the teeth enables simultaneous  engagement, which ensures sealing between individual interdependent gaps.

COR pump advantages over other types of pumps are




 * Economically interested production  price (all pumping parts are produced with injection molding of dimensionally stable polymer material with high mechanical & thermal performance),


 * Robustness against particle contamination corrosion resistance,


 * good hydraulic characteristics,
 * small dimensions,
 * high working pressure and
 * bi-directional (backward) rotation.

Motion of the pump rotor is determined by the rotation of the rotor of the e-motor and with the position relative to the gear shape of the pump stator. Sliding movement occur on flat surfaces between pump rotor and the rotor of the e-motor.

Pump rotor rotates with 1/8 of the angular speed of the rotor of the e-motor. In addition, it makes a change angle around the apparent point above the upper plane on the pump rotor. Composed motion causes the inter gap between the stator's gears and the rotor gears. As a consequence, there is a vacuum (under pressure) on one side and overpressure on the opposite side that causes suction and displacement of the pumping medium.

Image which shows the assembly of pumping parts, where red co-color depicts the pressure area and the blue part depics the suction side of the pump. In addition to a pair of pumping parts, the pump consists of a motor rotor and a stator of e-motor. Electric motor rotor has 2 journal bearings positioned between the magnet of e-motor.