The last step in completing the chassis of the DUT11 was applying the paintjob. The paintjob of the car is a feature on which the car can distinguish itself from others and by which it gets its unique look. Cars from Delft have been famous for their well thought paintjobs. The first stop for the bare chassis was Glasurit were the base layer of the paintjob was painted. Glasurit is a company specialised in paint repair for cars. Painting our car was obviously no problem and that is visible when looking at the result. Because time means everything in our project, the car was brought to its second stop quickly after the paint was cured in an oven. Custom Painting Holland customized the paintjob and created the unique finish. Besides adding the paintjob CPH also collaborated with us in the creative process of getting to this design. The result of the joint effort of both companies is astonishing. Everybody is therefore advised to check this out at the roll out of the DUT11 the 14th of June at the market square in Delft.
Today, the pinion gears arrived in our workshop. These pinion gears are assembled on the outgoing shaft of our motors, and will transfer the power to the large gear and therefore also the driveshaft. The pinion gears are fixed on the outgoing shaft of the motor with a ‘spline connection’. This can be seen on the photograph.
At Ter Hoek Vonkerosie the splines where made in our pinion gears with spark machining. Spark machining is a machining process in which current is passed through a wire. This wire is slowly moved through the workpiece, where via small sparks (hence the name ‘spark machining’) material is removed. With this type of process very delicate and complex shapes can be made, such the shape of our splines. Ter Hoek Vonkerosie has made these splines in a very short period of time for us, which now allows us to start assembling our drivetrain in the DUT11!
This year, the power transmission is done by gears instead of a chain. The transmission of the DUT11 is responsible for the transmission of the power from the electric motor to the drive shaft. From the drive shaft the power is transmitted via the wheels on the road. The main reason to choose for gears instead of a chain, is the large transmission ratio (1:7,2). This large transmission ratio is needed for the electric motors who will operate in a high RPM range (max. 10.000 RPM). A chain can’t transmit power at this high ratio in one step; a double step chain transmission would take too much space.
Because the development of a set of gears is very complex, we contacted a company that is specialized in this field: Drenth Motorsport Gearboxes. This company is has a lot of experience in the field of developing custom made gearboxes. Drenth Motorsport Gearboxes helped us by sharing their expertise and gave us very helpful advises during the design period. Eventually a perfect set of gears was designed that suits the behaviour of the electric motors.
The production of gears is a very specialized process. Therefore, Drenth Motorsport Gearboxes have produced our gears in their factory. The gears for the DUT11 are produced from a special kind of steel: a kind of steel that can operate in the most extreme conditions, and can handle various shock loads. At this moment the gears arrived in our workshop. They are now ready for further processing. After that, they can be assembled in our car. It won’t take much longer before the gears will drive the DUT11. We would like to thank Drenth Motorsport Gearboxes for all their shared expertise, and mostly for producing the gears!
Just like last years, our electronics department is supported by NXP Semiconductors. For the self-designed printed circuit boards we use several components which are supplied by NXP. The most important one is probably the LPC1769 ARM Cortex-M3 microcontroller which contains all software. We use this microprocessor on our electronic control unit to control the motor controllers, monitor the safety systems and for the data-acquisition. The printed circuit boards in the dashboard and the steering wheel which are used for the interface with the driver also contain this microprocessor. Communication between the microprocessors is done through the CAN-bus. Therefore we use TJA1051T/3 CAN Transceivers.
Our biggest self-designed printed circuit board, the mainboard of the electronic control unit, can be assembled by NXP. This saves us a lot of money and time so we can focus ourselves 100% on designing and assembling the other printed circuit boards. Last week we received our assembled mainboard from NXP, and as can be seen on the picture everything is attached perfectly straight. We could never have reached this result by hand, and therefore we would like to thank NXP for their help!
Packages small and large have been streaming in the last couple of weeks at DUT Racing. The one after the other, one with a more interesting content than the other. Last week however, we took delivery of a very special package: the one containing the motors for the DUT11. 3 motors, all of which were fabricated by AMK Antriebe in Germany. The motors, permanent magnet synchronous type each weigh only 11,9kg and produce peak power of about 28kW! The motors operate at 350V and spin up to a maximum of 10500RPM. Two of the motors will be used in the DUT11, bringing the total power output to 56kW, about 50% more than the DUT10. This increase in power will probably provide for some spectacular performances and we are very anxious to see what this will bring at the competition!
Electric motors, like those provided by AMK, are ideally suited for a race car like the DUT11. The peak torque is available right from 0 RPM up until halfway the rev range. This means that the available power can be optimally used, ensuring that you have all the power you need to get a good exit out of a corner. Besides this, the motors are also lightweight and very efficient, meaning they are ideally suited for the DUT11.
