Controller

1. A controller comprising:

a casing having a rectangular solid shape and including

a front panel including an intake port,

a rear panel including a discharge port and arranged so as to be opposed to the front panel, and

a heat transfer wall arranged so as to be perpendicular to the front panel and the rear panel, the heat transfer wall including an opening portion through which an inside and outside of the casing communicate with each other;

a fan arranged inside the casing and configured to suck outside air into the casing through the intake port and supply the air to the inside of the casing;

a regenerative resistor provided inside the casing so as to be located at a position where the regenerative resistor is exposed to the outside through the opening portion of the heat transfer wall, the regenerative resistor being insertable and detachable through the opening portion;

electronic parts provided inside the casing and including a servo amplifier which makes the regenerative resistor consume electric power; and

a lid body detachably attached to the heat transfer wall and configured to seal the opening portion.

2. The controller according to claim 1 , wherein:

a resistor attaching portion is provided inside the opening portion of the heat transfer wall;

the resistor attaching portion includes

an attaching wall located inside the casing and parallel to the heat transfer wall and

a pair of side walls connecting the attaching wall and the heat transfer wall; and

the regenerative resistor is detachably attached to the attaching wall.

3. The controller according to claim 2 , wherein the heat transfer wall and the resistor attaching portion are configured as an integrally molded body made of an aluminum alloy.

4. The controller according to claim 1 , wherein:

a cable pull-out portion is formed at an opening edge of the opening portion of the heat transfer wall, the cable pull-out portion forming a passage through which a regenerative resistance connecting cable connected to the regenerative resistor is pulled out from the inside of the casing to the outside; and

a dustproof seal is provided at the cable pull-out portion, the dustproof seal sealing between the cable pull-out portion and the regenerative resistance connecting cable, extending through the cable pull-out portion, by sealing the opening portion with the lid body.

5. The controller according to claim 4 , wherein a connector to which the regenerative resistance connecting cable is connected is provided inside the casing so as to be located at a position where the connector is exposed to the outside through the opening portion of the heat transfer wall.

6. The controller according to claim 1 , further comprising:

a front cover attached to the front panel and configured to seal the intake port;

a rear cover attached to the rear panel and configured to seal the discharge port;

a base provided at the rear cover, the regenerative resistor being detachably attached to the base;

an open-type heat transfer wall cover covering at least the heat transfer wall and the regenerative resistor attached to the base, the heat transfer wall cover forming a cooling passage extending along a surface of the heat transfer wall; and

a fan provided inside the heat transfer wall cover and configured to suck the outside air into the cooling passage and supply the air to the cooling passage.

7. The controller according to claim 6 , further comprising a heat sink provided inside the cooling passage and attached to the heat transfer wall so as to cover the heat transfer wall and the lid body sealing the opening portion.