Help!! Problem rotation axes: Axes turns wrong

Problem rotation axes: Axes turns wrong
Problem rotation axes: Axes turns over 360 degrees
Posted: 10:03 PM 4 Hours Ago
Hi everyone, I have a problem with the axis of a gameobject, it's a backhoe arm (three emparenting gameobject) assigned a pivot to move each component(gameobject) , something like this:
*
Pivot 1 ->
Arm 1 ->
Pivot 2 ->
Arm 2 ->
Pivot 3 ->
shovel

The problem is that when the pivot turns around the x axis only reaches 90 º and -90° , and the other axes are increasing to 180 degrees, and if I turn it again it increase to 360 degrees ,and so it goes even more than a thousand degrees. This is an example:

Start:
Rotation: x = 0 y = 0 z = 0
Rotation: x = 90 y = -0 z = 0
//over it 90º
Rotation: x = 48 y = -180 z = -900
//over it 90º again
Rotation: x = 48 y = -360 z = -1080

This occurs in the inspector and during the game is running, I have not changed anything by script.

The model is made ​​in Blender evenI thought that the error came from there, and in this modeling program related the gameobjects (parent -> child) and happen the same, really I don´t know what to do. I ask for your help please.