<?php

    $array = array ('1' => array ( '0' => array ( 'id' => 1, 'data_id' => 1, 'time_id' => 1, 'data' => 1 ), '1' => array ( 'id' => 2, 'data_id' => 1, 'time_id' => 2, 'data' => 3 ), ),
    '2' => array ( '0' => array ( 'id' => 6, 'data_id' => 2, 'time_id' => 1, 'data' => 7 ), '1' => array ( 'id' => 7, 'data_id' => 2, 'time_id' => 2, 'data' => 4 ) ));
    
	$i= 0;
	$n= 0;
    $series = array();
	foreach($array as $dato)
	{
		$series[$i] = array();
		foreach($dato as $data)
		{
			foreach($data as $key => $value)
			{
				if($key == 'data')
				{
					$series[$i][$n] = $value;
					$n++;
				}
			}
		}
		$n = 0;
		$i++;
	}
    var_dump($series);