Abstract:
Specific pressure and temperature conditions of an engine being measured are achieved by a compressor and a coolant controller, and bore distortion is measured as a gap between a rotation unit and a cylinder wall, wherein the measuring position may be vertically and angularly varied.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This application claims priority of Korean Application No. 10-2003-0073891, filed on Oct. 22, 2003, the disclosure of which is incorporated fully herein by reference. 
   FIELD OF THE INVENTION 
   Generally, the present invention relates to an apparatus for measuring bore distortion of a cylinder block. More particularly, the present invention relates to an apparatus for measuring bore distortion of a cylinder block that can measure the bore distortion with respect to engine driving conditions including a temperature condition and a pressure condition of the cylinder block. 
   BACKGROUND OF THE INVENTION 
   In general, a bore of a cylinder block may be temporarily or permanently distorted by the fastening torque of a cylinder head bolt, coolant temperature, and a combustion pressure of a combustion chamber, etc. When such distortion of a cylinder is excessive, the engine may consume excessive lubricant. 
   Therefore, bore distortion should be precisely measured with respect to various engine operating conditions to assist in engine design. 
   According to an apparatus for measuring a bore distortion of a cylinder block of the prior art, bore distortion caused by a fastening torque of a cylinder head bolt was the only factor that could be precisely measured. Measurement of bore distortion of a cylinder caused by variations in coolant temperature showed a large error or the apparatus for measuring such bore distortion was very inefficient or uneconomical. 
   The information disclosed in this Background of the Invention section is only for enhancement of understanding of the background of the invention and should  not be taken as an acknowledgement or any form of suggestion that this information forms the prior art that is already known in this country to a person of ordinary skill in the art. 
   SUMMARY OF THE INVENTION 
   The present invention relates to an apparatus for measuring bore distortion of a cylinder block with the capability of measuring the bore distortion with respect to engine driving conditions including temperature and pressure of the cylinder block. 
   An exemplary apparatus for measuring a bore distortion of a cylinder block according to an embodiment of the present invention includes a compressor for applying pressure to the bore of a cylinder block, a coolant controller for temperature control of the cylinder block, a slider unit mounted in the cylinder block slidably along a longitudinal direction of the cylinder block, a first driving unit for sliding the slider unit in the longitudinal direction of the cylinder block, a rotation unit rotatably mounted to an end of the slider unit, a second driving unit for rotating the rotation unit, at least one first sensor laterally mounted to the rotation unit for detecting a clearance between the bore and the rotation unit, and a second sensor for detecting the longitudinal position of the slider unit. 
   In another embodiment, the compressor comprises a pneumatic pump. 
   In still another embodiment, threads are formed on an exterior circumference of the slider unit. 
   The slider unit may be rotatably supported by a bracket mounted to the cylinder block. 
   In a still further embodiment, a through-hole is formed at the bracket such that an end of the slider unit is inserted thereto, and a nut holds the slider unit inserted through the through-hole. 
   In still another embodiment, the first driving unit includes a first drive motor, and a first driveshaft connected to a rotating shaft of the first drive motor, wherein the first driveshaft has threads on its circumference. 
   In a further embodiment, an insertion hole is formed through a center of the rotation unit such that an end of the slider unit is inserted thereto, a circular  indentation is formed on a bottom side of the rotation unit, and teeth are formed on an interior wall of the indentation. 
   In a yet further embodiment, the second driving unit includes a second drive motor, and a second driveshaft connected to a rotating shaft of the second drive motor, wherein the second driveshaft has teeth on its circumference. 
   In a yet further embodiment, the at least one first sensor is provided as a pair thereof on an exterior circumference of the rotation unit. 
   In a yet further embodiment, the at least one first sensor is realized as a non-contact gap sensor for detecting a clearance between the rotation unit and an interior surface of the bore. 
   In still another embodiment, the second sensor is realized as a linear gauge contacting the slider unit for detecting a moved distance of the slider unit. 
   In a yet further embodiment, an apparatus further includes a pressure receiving plate disposed at the top of the slider unit, for receiving the pressure applied from the pressurizing device. 
   An O-ring may be disposed to an exterior circumference of the pressure receiving plate, for containing the pressure acting thereon. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate an embodiment of the invention, and, together with the description, serve to explain the principles of the invention: 
       FIG. 1  illustrates an apparatus for measuring a bore distortion of a cylinder block according to an embodiment of the present invention; and 
       FIG. 2  is an enlarged sectional view of a portion A of  FIG. 1 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
   An embodiment of the present invention will hereinafter be described in detail with reference to the accompanying drawings. 
     FIG. 1  illustrates an apparatus for measuring distortion of a cylinder block bore according to an embodiment of the present invention, and  FIG. 2  is an enlarged sectional view of a portion A of  FIG. 1 .  
   As shown in  FIGS. 1 and 2 , an apparatus  100  for measuring a bore distortion of a cylinder block  17  according to an embodiment of the present invention includes a compressor  10  for applying pressure to a bore  19  of the cylinder block  17 , a coolant controller  20  for controlling temperature of the coolant supply to the cylinder block  17  for temperature control of the cylinder block  17 , a slider unit  30  mounted in the cylinder block  17 , the slider unit being slidable along a longitudinal direction of the cylinder block  17 , a first driving unit  40  for sliding the slider unit  30  along the longitudinal direction of the cylinder block  17 , a rotation unit  50  rotatably mounted to an end of the slider unit  40 , a second driving unit  60  for rotating the rotation unit  50 , at least one first sensor  70  laterally mounted to the rotation unit  50  for detecting a clearance between the bore  19  and the rotation unit  50 , and a second sensor  80  for detecting longitudinal position of the slider unit  30 . Reference number  21  indicates an amplifier for amplifying a signal. 
   The compressor  10  includes a pneumatic pump (not shown). The pneumatic pressure of the compressor  10  is supplied through a supply line  11  to a nozzle  13  connected at an end of the supply line  11 . The nozzle  13  is mounted on a cylinder head  15  such that it may output the pneumatic pressure to the bore  19  of the cylinder block  17 . The compressor  10  creates a pressure corresponding to a combustion pressure occurring in a normal operation of the engine. 
   The coolant controller  20  is disposed near the cylinder block  17  and the cylinder head  15 . A coolant of a temperature corresponding to a coolant temperature occurring in normal operation of the engine is supplied to the cylinder block  17  and the cylinder head  15  by the coolant controller  20 . 
   As shown in  FIG. 2 , the slider unit  30  is slidable in the cylinder block  17  along the longitudinal axis of the bore  19 . 
   A bracket  12  is mounted at a lower end of the cylinder block  17 , and the slider unit  30  is mounted to the bracket  12 . In more detail, a through-hole  14  is formed at the bracket  12 , and an end of the slider unit  30  is inserted thereto. A nut  16  holds the slider unit  30  inserted through the through-hole  14 . Reference number  18  indicates a bolt for mounting the bracket  12  to the cylinder block  17 .  
   Threads are formed on the exterior circumference of the slider unit  30 . The first driving unit  40  is disposed adjacent to the slider unit  30 . When operated, the first driving unit  40  slides the slider unit  30  along the longitudinal axis of the bore  19 . 
   The first driving unit  40  includes a first drive motor  41  and a first driveshaft  43  connected to a rotating shaft of the first drive motor  41 . The first driveshaft  43  has threads on its circumference that engage the threads of the slider unit  30 . The engagement between the threads of driveshaft  43  and the threads of slider unit  30  cause the slider unit  30  to move along the longitudinal axis of the bore  19 . 
   As described above, the rotation unit  50  is rotatably mounted to an end of the slider unit  40 . An insertion hole  51  is formed through a center of the rotation unit  50 , and an end of the slider unit  30  is inserted thereto. On a bottom side of the rotation unit  50 , a circular indentation  53  is formed adjacent to the insertion hole  51 . Teeth are formed on an interior wall of the indentation  53 . The rotation unit  50  receives torque from the second driving unit  60  and can rotate thereby. 
   The second driving unit  60  includes a second drive motor  61  and a second driveshaft  63  connected to a rotating shaft of the second drive motor  61 . The second driveshaft  63  has teeth on its circumference, and engages the teeth on the interior wall of the indentation  53  such that the rotation unit  50  may be gear-driven by the second driveshaft  63 . 
   The at least one first sensor  70  is laterally mounted to the rotation unit  50 . The at least one first sensor  70  is provided as a pair thereof on an exterior circumference of the rotation unit  50 . The first sensor  70  is a non-contact gap sensor for detecting a clearance between the rotation unit  50  and an interior circumference of the bore  19 . 
   Such a first sensor  70  rotates within the bore  19  together with the rotation unit  50 , and can slide in the longitudinal direction of the bore  19  together with the rotation unit  50  such that bore distortion may be measured at every longitudinal position. 
   The second sensor  80  is a linear gauge contacting the slider unit  30  for detecting a moved distance of the slider unit  30 . 
   A third sensor  90  is disposed within the indentation  53  of the rotation unit  50  such that angular position of the rotation unit  50  can be measured. The third  sensor  90  is a gap sensor for detecting a rotation of threads formed at the second driveshaft  63 . 
   A pressure receiving plate  91  is disposed at a top of the slider unit  30 . The pressure receiving plate  91  is circularly shaped to fit to a cross-section of the cylinder. The pressure receiving plate  91  receives the pressure applied from the compressor  10 . 
   An O-ring  93  is disposed on an exterior circumference of the pressure receiving plate  91 . The O-ring  93  contains the pressure supplied by the compressor  10 , preventing a leakage thereof between the pressure receiving plate  91  and the interior wall of the bore  19 . 
   An operation of the apparatus for measuring bore distortion of a cylinder block according to an embodiment of the present invention is described hereinafter. 
   First, by operating the compressor  10  and the coolant controller  20 , normal operating pressure and temperature conditions of the engine are simulated. 
   Subsequently, by operating the first driving unit  40 , the slider unit  30  is moved to a target measuring position along the longitudinal direction of the bore  19 . 
   And then, while rotating the rotation unit  50 , bore distortion is measured by the first sensor  70  at a plurality of horizontal positions. Here, the second sensor  80  detects the longitudinal position of the slider unit  30  and the third sensor  90  detects the angular position of the rotation unit  50 . 
   According to the above-described process, bore distortion may be measured at a variety of engine temperature and pressure conditions because the temperature and pressure may be changed by operating the compressor  10  and the coolant controller  20 . 
   As described above, an apparatus for measuring a bore distortion of a cylinder block according to an embodiment of the present invention provides the following effects. 
   Bore distortion may be measured at a variety of engine temperature and pressure conditions. 
   In addition, costs for such a measuring apparatus may be lowered since the temperature and pressure may be changed by operating the compressor  10  and the coolant controller  20 .  
   While this invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the invention is not limited to the disclosed embodiments, but, on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims.