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Upgrade of the steering system

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This page explains why we decided to upgrade the steering system and how we did it.

Contents

Why to upgrade

We had mainly two problems with the previous version of the steering actuation:

  • the belt transmission was not efficient: the belt weared, missed some teeth;
  • the previous design did not allow to release the transmission and turn to manual control.

For these reasons we decided to turn to a gear transmission, with a safety system to allow to move quickly the motor (with his gear) away from the wheel axis, so to allow reverting to manual control.

The design

The new steering system is composed by three aluminum pieces, plus two gears. The first piece, the "enclosure", is an aluminum profile with a rectangular section (80 x 40, thickness 4), similar to the one used in the previous system. It is fixed to the steering axis in the same way of the previous system. A second piece, the "turning door", is an aluminum block fixed to the first one by means of a 6mm diameter axis, around which it can rotate; the rotation allows to separate the motor from the wheel axis. The third piece, the "motor holder", is fixed with screws to the turning door, and it is another aluminum block to which the (gearbox of the) motor (group) is connected by means of screws. One gear is mounted on the output shaft of the motor group, the other on the wheel axis.

There are some other details not represented in the drawings:

  • The 6mm diameter axis, made of steel, is kept in place by two Seeger rings, and there is a thorn, which fits in a hollow in the enclosure, which prevents the axis to rotate.
  • To keep the gears coupled there is a toggle latch, fixed on the enclosure, which holds the turning door and the rest in place; the latch latches the turning door at its protrusion from the enclosure.
  • There is a spring, extending from the container (in the side opposite to the wheel axis) to the turning door, in order to pull the turning door away as soon as the lacth is released.

The realization

We commissioned the execution of the pieces described above to an external workshop company.

Post-1st-design adjustments to the design, to make everything fit :-)

  • keep in mind which pieces have to be joined, so to leave some space for air
  • enlarge the six small holes in the enclosure, to let the screws pass.

Moreover, we deliberately left some processing to be done, by design, after mounting the whole:

  • prepare the 6mm axis, with the Seeger rings, the thorn, and the hollow,
  • find and mount the spring,
  • find and mount the toggle latch with springs (see page 18 of this product list, item 2.42.00),
  • file the little opening, in the side of the enclosure, where the turning door protrusion protrudes, so to couple correctly the two gears
  • prepare the hole for a Seeger ring on the motor output shaft, to hold the gear in place

Final adjustments

Mounting and testing

Recommended sequence:

  1. Insert into the box the six bolts to connect the box to the steering
  2. Insert the bigger gear in the box
  3. Insert the block key in the relative hole in the steering axis
  4. Insert the box in the steering axis so that the bolts and the block key are in the right position
  5. Screw the bolts
  6. Screw the motor support to the rotating door
  7. Attach the spring to the rotating door and to the top lid
  8. Insert the rotating door in the box
  9. Screw the motor to the support
  10. Insert the axis to block the rotating door
  11. Insert the gear on the motor shaft
  12. Screw the latch
  13. Insert the seeger ring on the little axis

Other Photos

IMG20111026_002.jpg IMG20111026_003.jpg IMG20111026_004.jpg IMG20111026_005.jpg IMG20111026_006.jpg
The whole system mounted on the wheel axis Wheel axis gear Wheel axis gear as seen from inside the enclosure Turning door and motor holder assembled Turning door and motor holder assembled
IMG20111026_007.jpg IMG20111026_008.jpg IMG20111026_009.jpg IMG20111026_010.jpg IMG20111026_011.jpg
The whole system, without the turning door axis Turning door protrusion, protruding from the little window in the side of the enclosure, the window and/or the protrusion are going to be filed Entire project, the toggle latch will be positioned on the side of the enclosure, between the turning door protrusion and the window for the wheel axis gear Turning door and motor holder assembled, from inside Turning door and motor holder assembled, and motor
IMG20111026_012.jpg IMG20111026_013.jpg IMG20111026_014.jpg IMG20111027_001.jpg IMG20111027_002.jpg
Turning door and motor holder assembled and mounted, with the steel axis before its cut Turning door and motor holder assembled and mounted, with the steel axis before its cut Wheel axis gear Hole for the wheel axis, with the hollow for the thorn Wheel axis with thorn
IMG20111027_003.jpg IMG20111027_004.jpg IMG20111027_005.jpg
Wheel axis in place Seeger ring space Seeger ring
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