specifying the spec of motor in URDF

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Hi, I'm trying to make a gazebo ros simulation environment for my robot. (gazebo 9, ros melodic)

What I am doing now is adding a specific motor to my robot. Simply saying, I want each motor on my robot to have max velocity, max acceleration, max torque (e.g. 4.86 mNm), and so on.

I add limits(effort and velocity) on my URDF. but it doesn't affect the gazebo which means the robot moves at the same velocity.

I wonder if anyone can give some guidance on where should I start to look for.

Thanks,

ps. If it's about the Gazebo thing, I will move my question to the Gazebo forum.