Bicycle Mechanics - Lubricatng trailer wheels

Last weekend I got an old kids carrier (Rand Kidkaboose) for $15. It has wheel hubs that don't appear to have ball bearings. I have not figured out how to take them apart to grease them.
There appears to be a cap on the outside end of the hub.
How do I grease them?

Here's a couple of better photos. There's no cone or nuts to loosen.

This is a guess, but I expect if you pry off the end cap you will find a cone and locknut under it and cup and cone bearings at both ends of the axle.

Once you loosen and remove the outer locknut/cone, the axle will slide out to the inside to let you clean and service the inner bearings too.

Thanks Hillrider. When I tried to pry the cap off, it became obvious that it was part of the axle. A few taps with a hammer on the inside end pushed the axle through. Now the bearings still can't be gotten to. There's a 1/2" tube on both ends of the hub, that are free to turn but don't appear to be removeable.
At this point, I might just pack grease in the 1/16" space between the inner hub and the rotating end tubes.

I have no experience with these trailers but those look like sealed bearing not cup and cone.If the bearings are bad,they will be replaced as a unit.There will be 4 sealed bearing,2 in each hub.

You may still be able to grease it using a grease gun and a needle injector.

Thanks to all who replied. When I tried to take the axle out of the other wheel, the outside sealed bearing popped out. The bearings don't seem bad, so I will see if I can inject some grease into them.