Empty post response ajax

I'm trying to use ajax to geta response from a codeigniter controller method but it doesn't work ,the response it's empty.

    <script type="text/javascript">
            $(document).ready(function(){
                $("#crear").click(function() {
                    //$('#error_msg').html("Error");
                    $.ajax({
                        type:"POST",
                        url:"clase/create",
                        success:function(data){
                            $('#error_msg').html(data);
                        }
                    });
                });
            });
    </script>

and this is the controller

<?php if ( ! defined('BASEPATH')) exit('No direct script access allowed');

class Clase extends CI_Controller {

 function __construct()
 {
   parent::__construct();
   $this->load->model('clase_model','',TRUE);
   $this->load->helper(array('form'));
 }

 function index()
 {
    if($this->session->userdata('logged_in')){
        $data['title'] = 'Gestión de Clases';
        $data['clases'] = $this->clase_model->getAll();
      $this->load->view('header', $data);
      $this->load->view('clase_view', $data);

     }
     else{

          redirect('login', 'refresh');
     }
 }

 function create(){
    if($this->session->userdata('logged_in')){
      $this->load->library('form_validation');
      $this->form_validation->set_rules('name', 'Nombre', 'trim|min_length[2]|required');
      $this->form_validation->set_rules('info', 'Información', 'trim');

       if($this->form_validation->run() == FALSE){
          $data = array(
            'error_message1' => form_error('name'),
            'error_message2' => form_error('info')
            );
           return $data['error_message1'];
       }
       else{
          if($this->input->post('info')){
             $this->insert2($this->input->post('name'),$this->input->post('info'));
          }
          else{
            $this->insert1($this->input->post('name')); 
          }
       }   
    }
    else{
          redirect('login', 'refresh');
    }
 }

 function insert2($name,$information){
    $dat = array(
      'nombre'=>$name,
      'info'=>$information
    );
    $this-> db ->insert('clase',$dat);

    echo $name;
    redirect('clase', 'refresh');
 }
 function insert1($name){
    $dat = array(
      'nombre'=>$name,
    );

    $this-> db ->insert('clase',$dat);
    redirect('clase', 'refresh');
 }
}
?>

and the response header

Cache-Control   
no-store, no-cache, must-revalidate, post-check=0, pre-check=0
Connection  
Keep-Alive
Content-Length  
0
Content-Type    
text/html; charset=UTF-8
Date    
Sat, 25 Apr 2015 16:04:47 GMT
Expires 
Thu, 19 Nov 1981 08:52:00 GMT
Keep-Alive  
timeout=5, max=100
Pragma  
no-cache
Server  
Apache/2.4.10 (Win32) OpenSSL/1.0.1i PHP/5.6.3
Set-Cookie  
ci_session=941a601d7eaf9f590d21bd4c0aa8c2ac043faa81; expires=Sat, 25-Apr-2015 18:04:47 GMT; Max-Age=7200
; path=/; httponly
x-powered-by    
PHP/5.6.3

Somebody can tell me what is wrong?it's my first time with ajax