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Initial commit for new branch with reversed brake arm direction on y-axis so that mechanical shocks at the wheel cause brakes to ease off, rather than jolting onto application.

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Teddy Middleton-Smith
2025-02-25 15:49:37 +00:00
parent 659001351e
commit cd60aff3e5
10 changed files with 18 additions and 9 deletions
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2
models/brake/brake_arm.scad
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@@ -7,7 +7,7 @@ module brake_arm() {
// body
cube(R_BRAKE_ARM, center = true);
// chamfer across end face for wheel overlap
translate([R_BRAKE_ARM[0] / 2 - R_BRAKE_ARM[1] / 2 * tan(ANGLE_BRAKE_ROD_MAX), 0, 0]) rotate([0, 0, 90 - ANGLE_BRAKE_ROD_MAX]) translate([0, -L_big / 2, -L_big / 2]) cube(L_big, center = false);
translate([R_BRAKE_ARM[0] / 2 - R_BRAKE_ARM[1] / 2 * tan(ANGLE_BRAKE_ROD_MAX), 0, 0]) rotate([0, 0, -(90 - ANGLE_BRAKE_ROD_MAX)]) translate([0, -L_big / 2, -L_big / 2]) cube(L_big, center = false);
}
// Shopping
echo(str("Brake arm: Aluminium sheet ", R_BRAKE_ARM[1], "mm x ", R_BRAKE_ARM[0], "mm x ", R_BRAKE_ARM[2], "mm - x1"));

6
models/brake/brake_assembly.scad
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@@ -38,13 +38,13 @@ module brake_assembly(angle_brake_rod) {
for (index_side_x = [0:1:1]) {
mirror([index_side_x, 0, 0]) {
translate([X_OFFSET_FIXING_BRAKE_ARM_TO_LEAD_PLATE, 0, 0]) rotate([0, 0, -(90 - angle_brake_rod)]) {
translate([X_OFFSET_FIXING_BRAKE_ARM_TO_LEAD_PLATE, 0, 0]) rotate([0, 0, (90 - angle_brake_rod)]) {
// brake arm
translate([R_BRAKE_ARM[0] / 2, 0, 0]) brake_arm();
// fixing brake arm to brake pad
translate([R_BRAKE_ARM[0] - X_OFFSET_FIXING_BRAKE_ARM_TO_BRAKE_PAD_FROM_END, 0, R_BRAKE_ARM[2] / 2]) rotate([0, 0, 90 - ANGLE_BRAKE_ROD_MAX]) fixing_brake_arm_to_brake_pad();
translate([R_BRAKE_ARM[0] - X_OFFSET_FIXING_BRAKE_ARM_TO_BRAKE_PAD_FROM_END, 0, R_BRAKE_ARM[2] / 2]) rotate([0, 0, -(90 - angle_brake_rod)]) fixing_brake_arm_to_brake_pad();
// brake pad
translate([R_BRAKE_ARM[0] - X_OFFSET_FIXING_BRAKE_ARM_TO_BRAKE_PAD_FROM_END, 0, R_BRAKE_ARM[2] / 2 + T_FIXING_BRAKE_ARM_TO_BRAKE_PAD + (W_FIXING_BRAKE_ARM_TO_BRAKE_PAD - T_FIXING_BRAKE_ARM_TO_BRAKE_PAD) / 2]) rotate([0, 0, 90 - ANGLE_BRAKE_ROD_MAX]) translate([T_FIXING_BRAKE_ARM_TO_BRAKE_PAD, 0, 0]) brake_pad();
translate([R_BRAKE_ARM[0] - X_OFFSET_FIXING_BRAKE_ARM_TO_BRAKE_PAD_FROM_END, 0, R_BRAKE_ARM[2] / 2 + T_FIXING_BRAKE_ARM_TO_BRAKE_PAD + (W_FIXING_BRAKE_ARM_TO_BRAKE_PAD - T_FIXING_BRAKE_ARM_TO_BRAKE_PAD) / 2]) rotate([0, 0, -(90 - angle_brake_rod)]) translate([T_FIXING_BRAKE_ARM_TO_BRAKE_PAD, 0, 0]) brake_pad();
}
// fixing brake arm to rear axle leg
translate([X_POS_AXLE_LEG_REAR, -y_pos_lead_fixing_ballscrew_to_brake_arms + Y_POS_AXLE_REAR, 0]) fixing_brake_arm_to_rear_axle_leg();

2
models/brake/brake_assembly_functions.scad
View File

@@ -1,3 +1,3 @@
// include <../../config.scad>; // circular reference!
function get_y_pos_lead_fixing_ballscrew_to_brake_arms(angle_brake_rod, y_pos_axle_rear, x_pos_axle_leg_rear, x_offset_fixing_brake_arm_to_lead_plate) = y_pos_axle_rear + (x_pos_axle_leg_rear - x_offset_fixing_brake_arm_to_lead_plate) / tan(angle_brake_rod); // (X_POS_AXLE_LEG_REAR - X_OFFSET_FIXING_BRAKE_ARM_TO_LEAD_PLATE)
function get_y_pos_lead_fixing_ballscrew_to_brake_arms(angle_brake_rod, y_pos_axle_rear, x_pos_axle_leg_rear, x_offset_fixing_brake_arm_to_lead_plate) = y_pos_axle_rear - (x_pos_axle_leg_rear - x_offset_fixing_brake_arm_to_lead_plate) / tan(angle_brake_rod); // (X_POS_AXLE_LEG_REAR - X_OFFSET_FIXING_BRAKE_ARM_TO_LEAD_PLATE)

2
models/brake/fixing_brake_arm_to_rear_axle_leg.scad
View File

@@ -9,7 +9,7 @@ module fixing_brake_arm_to_rear_axle_leg() {
count_washers_each_end = 3;
h_nut = get_metric_bolt_head_height(SIZE_BOLT_FIXING_BRAKE_ARM_TO_REAR_AXLE_LEG);
L_bolt = D_AXLE_REAR + 2 * (T_WASHER_BOLT_FIXING_BRAKE_ARM_TO_REAR_AXLE_LEG * count_washers_each_end + h_nut) + L_BOLT_EXTENSION;
rotate([0, 0, ANGLE_BRAKE_ROD_MAX]) for (index_side_z = [0 : 1 : 1]) {
rotate([0, 0, -ANGLE_BRAKE_ROD_MAX]) for (index_side_z = [0 : 1 : 1]) {
mirror([0, 0, index_side_z]) translate([0, 0, R_BRAKE_ARM[2] / 2]) {
// axle washer
translate([0, 0, 0]) washer(T_WASHER_AXLE_FIXING_BRAKE_ARM_TO_REAR_AXLE_LEG, D_WASHER_AXLE_FIXING_BRAKE_ARM_TO_REAR_AXLE_LEG, D_AXLE_REAR, centre = false);