The torque that needs to be applied for this joint to break.
The torque might come from collisions with other objects, forces applied with rigidbody.AddTorque or from other joints. See Also: Joint.OnJointBreak
// Makes the joint break when a torque larger than 10 is applied
hingeJoint.breakTorque = 10;
// Makes the joint unbreakable
hingeJoint.breakTorque = Mathf.Infinity;