Internal venting system for industrial machines

1. A mining shovel comprising:

a boom;

a transmission unit coupled to the boom, the transmission unit including:

an outer housing;

an internal motor housing disposed within the outer housing; and

a venting system coupled to the outer housing to direct air through both the outer housing and the internal motor housing.

2. The mining shovel of claim 1 , wherein the venting system includes a blower coupled directly to the outer housing.

3. The mining shovel of claim 1 , wherein the outer housing includes a gear case.

4. The mining shovel of claim 1 , wherein two internal motor housings are disposed within the outer housing.

5. The mining shovel of claim 1 , wherein the internal motor housing includes inlet apertures to receive air moving inside the outer housing.

6. The mining shovel of claim 5 , wherein the internal motor housing includes four inlet apertures.

7. The mining shovel of claim 6 , wherein the four inlet apertures are spaced approximately 90 degrees apart from one another on the internal motor housing.

8. The mining shovel of claim 1 , and further comprising an external motor housing that directs air out of the mining shovel.

9. The mining shovel of claim 1 , wherein the venting system includes ducting positioned inside the boom to deliver air to the outer housing.

10. The mining shovel of claim 9 , wherein the venting system includes a blower coupled to the ducting.

11. The mining shovel of claim 10 , wherein the blower is disposed on a lower end of the boom.

12. The mining shovel of claim 1 , wherein the venting system includes ducting positioned alongside an exterior surface of the boom to deliver air to the outer housing.

13. The mining shovel of claim 1 , wherein the venting system includes a blower positioned at a lower end of the boom.

14. The mining shovel of claim 1 , wherein the venting system includes a cavity inside the outer housing through which the air passes.