Abstract:
The invention concerns a method of mounting a cylinder arrangement of a hermetically enclosed refrigerant compressor arrangement in a carrier arrangement ( 14, 15 ), in which the cylinder arrangement is inserted in the carrier arrangement ( 14, 15 ), aligned in relation to a crank shaft ( 5 ) and connected to the carrier arrangement ( 14, 15 ). It is endeavored to ensure a good efficiency of the refrigerant compressor arrangement. For this purpose the carrier arrangement is deformed, before inserting the cylinder arrangement, by means of a calibration cylinder ( 40 ), until the calibration cylinder ( 40 ) has a predetermined alignment, after which the calibration cylinder ( 40 ) is removed and replaced by the cylinder arrangement in the carrier arrangement ( 14, 15 ).

Description:
CROSS REFERENCE TO RELATED APPLICATION 
     Applicant hereby claims foreign priority benefits under U.S.C. §119 from German Patent Application No. 10 2008 024 670.0 filed on May 21, 2008, the contents of which are incorporated by reference herein. 
     FIELD OF THE INVENTION 
     The invention concerns a method of mounting a cylinder arrangement of a hermetically enclosed refrigerant compressor arrangement in a carrier arrangement, in which the cylinder arrangement is inserted in the carrier arrangement, aligned in relation to a crank shaft and connected to the carrier arrangement. 
     BACKGROUND OF THE INVENTION 
     Further, the invention concerns a hermetically enclosed refrigerant compressor arrangement with a crank shaft and a cylinder arrangement, in which a piston is arranged that is connected to the crank shaft via a connecting rod, the cylinder arrangement being supported on a carrier. 
     Such a hermetically enclosed refrigerant compressor arrangement is, for example, known from U.S. Pat. No. 6,095,768, EP 0 524 552 A1 or U.S. Pat. No. 7,244,109 B2. 
     Hermetically enclosed refrigerant compressors are used in many domestic and industrial refrigeration appliances, for example, refrigerators, refrigerating chests, freezers, top opening freezers or refrigerating cabinets. They are manufactured in large numbers and must thus be regarded as mass products, which should be manufactured in the most cost effective way possible. 
     In order to simplify the manufacturing, the cylinder arrangements are, in the cases mentioned above, arranged on a carrier, which is made to be relatively stable, and which is connected to the stator of the drive motor. Thus, it is no longer required to make the cylinder arrangement and the bearing for the rotor of the drive motor in one piece. 
     Such an embodiment has the disadvantage that it is difficult to mount the cylinder arrangement of the refrigerant compressor arrangement with the exact alignment. It is desired to position the cylinder arrangement so that the axis of the cylinder arrangement extends exactly at right angles to the axis of the crank shaft. If this is not the case, this may cause cocking of the piston in the cylinder during operation, which would cause increased wear. A cocked cylinder also requires more energy during operation, which has a negative influence on the efficiency. 
     SUMMARY OF THE INVENTION 
     The invention is based on the task of ensuring a good efficiency of a refrigerant compressor arrangement. 
     With a method as mentioned in the introduction, this task is solved in that, before inserting the cylinder arrangement, the carrier arrangement is deformed by means of a calibration cylinder, until the calibration cylinder has a predetermined alignment, after which the calibration cylinder is removed and replaced by the cylinder arrangement in the carrier arrangement. 
     With this embodiment, a carrier arrangement (or short: a carrier) can be used, which has been pre-manufactured with a relatively poor accuracy. The accuracy of the manufacturing of the accommodation, in which finally the cylinder arrangement is inserted, will only be achieved by the use of the calibration cylinder. At least with regard to the diameter, the calibration cylinder has outer dimensions, which correspond to those of the cylinder arrangement. Otherwise, the calibration cylinder only has to be so stable that it can deform the carrier. Usually, in this connection, it is endeavoured to avoid a deformation of the calibration cylinder. When the calibration cylinder is acted upon by a sufficient force, it can deform the carrier. This deformation is controlled by the force applied, so that the axis of the calibration cylinder preferably crosses the axis of the crank shaft, or, if the cylinder is laterally offset in relation to the crank shaft axis, a parallel to the crank shaft axis. When, then, the calibration cylinder is removed from the carrier, the accommodation has a geometry, into which the cylinder arrangement fits exactly, so that also the axis of the cylinder arrangement crosses the crank shaft axis or a line that extends in parallel to the crank shaft axis. In any case, the cylinder arrangement can then be mounted so that its axis crosses the crank shaft axis or a parallel thereto under a right angle. 
     Preferably, a carrier arrangement is used with projections extending in the direction of the cylinder arrangement, and the projections are deformed. If only the projections must be deformed, a smaller force is required, than would be required for the deformation of the whole carrier arrangement. Accordingly, the deformation of the carrier arrangement can be made with a better accuracy. The risk that during the deformation of the carrier arrangement other parts of the carrier arrangement outside the projections are deformed in an undesired manner is relatively small. This means that the deformation of the carrier arrangement can be concentrated on an area, where the deformation is desired. 
     It is preferred that at least two rows of projections are used, projections being farther away from the crank shaft being higher than projections, which are closer to the crank shaft. With this embodiment, it is achieved that during insertion the calibration cylinder initially has an inclination in relation to the alignment, which it must finally assume. This inclination is pre-specified by the different heights of the projections. Thus, it is also specified, where a force must be applied in order to deform the projections. The calibration cylinder is then tilted from its inclined position to the desired position; the force applied deforming the higher projections more than the lower projections. This is a simple and fast way of achieving the desired deformation of the carrier arrangement. 
     It is preferred that in the area of the higher projections a press force is applied on the calibration cylinder. When the press force is applied in the area of the higher projections, it is applied, where it can immediately be active. It must be assumed that with this method, mainly the higher projections are deformed. This keeps the deformation work small. 
     It is preferred that two rows are provided, each row having two projections. This means that a total of four projections is provided, of which two are higher than the other two. Four projections provide a sufficiently stable support for the cylinder arrangement to be mounted. 
     Preferably, before connecting the cylinder arrangement to the carrier arrangement, the cylinder arrangement is displaced on the carrier arrangement in a direction perpendicular to the crank shaft axis, until a dead space inside the cylinder arrangement has reached a predetermined minimum value. After the deformation, the deformed projections or the deformation zone of the carrier arrangement as a whole are formed so that during a displacement along the axis of the cylinder arrangement, that is, perpendicular to the crank shaft axis, a change of the angle between the cylinder axis and the crank shaft axis will not occur. This can be utilised to displace the cylinder towards or away from the crank shaft, until the dead space occurring in the upper dead point of the piston has reached its minimum value. The smaller the dead space is, the better is the efficiency of the refrigerant compressor arrangement. 
     Preferably, a calibration cylinder is used, whose one front side extends perpendicular to its axis, and that in at least two positions a distance of the front side to the crank shaft axis, or a line parallel to that, is determined, the carrier arrangement being deformed, until the distances are equal. The two positions are offset in relation to each other in parallel to the crank shaft axis. As long as the calibration cylinder is inclined, the two positions have different distances to the crank shaft axis or a line parallel thereto. Not until one front side of the calibration cylinder is vertical, the distances are the same. In this case, however, the axis of the calibration cylinder extends perpendicular to the crank shaft axis or a line parallel thereto. 
     Preferably, the parallel line used is a line on the circumference of a crank pin, which is connected to the crank shaft. This is particularly advantageous, if the axis of the cylinder arrangement and the crank shaft axis do not cross, but the cylinder arrangement is laterally offset in relation to the crank shaft. Then, the crank pin can be turned to the desired position, and measuring can be performed. 
     It is also advantageous, if a carrier arrangement is used, which comprises a carrier element and a reinforcement element, the reinforcement element being deformed. The use of a reinforcement element makes it possible to reduce the mass of the carrier arrangement. The carrier element can be dimensioned with a view to the fixing on the stator and the reinforcement element can be dimensioned with a view to the fixing of the cylinder arrangement. Accordingly material only has to be provided, where it is required for the corresponding application purpose. Additionally, the use of two elements, which are joined, can provide acoustic advantages, as, for example, the intrinsic frequency of the joined carrier arrangement is displaced from the audible area, and vibrations are damped. The carrier element and the reinforcement element can, for example, be made as shaped metal sheet parts, which can be manufactured with the required accuracy in a cost effective manner. In order to achieve the ultimate accuracy of the alignment of the axis of the cylinder arrangement to the crank shaft axis, the reinforcement element is deformed. 
     Preferably, the cylinder arrangement and the carrier arrangement are joined by means of a cold-formed joint. The cold-formed joint can, for example, be achieved by toxing or clinching. Thus, auxiliary joining parts can be saved. Deformations caused by a thermal load can be avoided. Thus, the accuracy of the alignment is not influenced by the joining process. 
     With a refrigerant compressor arrangement as mentioned in the introduction, the task is solved in that the carrier arrangement has at least one deformed deformation zone. 
     When the cylinder arrangement is mounted, the deformation zone has previously been deformed by the calibration cylinder. Thus, in the deformation zone it can be determined, if such a deformation has taken place. The deformation of the deformation zone causes that the axis of the cylinder arrangement and the crank shaft axis or a line parallel thereto cross each other under a right angle. Thus, the piston can be guided in the cylinder without risking a cocking, which keeps the wear and the energy consumption during operation small. 
     Preferably, the deformation zone has several projections directed towards the cylinder arrangement, at least one of these projections being deformed. During the deformation, the height of the deformed projection is reduced, so that the axis of the cylinder arrangement gets the desired alignment, namely at right angles to the crank shaft axis or a line parallel thereto. 
     It is also advantageous, if a projection far away from the crank shaft is more deformed than a projection next to the crank shaft. With a carrier arrangement, whose deformation zone comprises more or less deformed projections, the projections would, before the deformation, have different heights. Accordingly, the calibration cylinder can be inserted in the deformation zone with a certain inclination, and this inclination can then be removed by an external force application, so that the axis of the cylinder arrangement gets the desired alignment. 
     Preferably, the carrier arrangement has a carrier element mounted on a motor and a reinforcement element connected to the cylinder arrangement, the deformation zone being located in the reinforcement element. As mentioned above, the carrier arrangement can then be made with a relatively small mass. The carrier element can be dimensioned for the mounting on the motor. The reinforcement element, however, is dimensioned for accommodating the cylinder arrangement. Accordingly, material will only be provided, where it is required for the individual purposes. With an assembled carrier arrangement, the resonant frequency can under certain circumstances be displaced into a non-audible range. 
     In the following, the invention is described on the basis of a preferred embodiment in connection with the drawings, showing: 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic, partial section through a refrigerant compressor arrangement, 
         FIG. 2  is a perspective view of a reinforcement element, and 
         FIG. 3  is a view according to  FIG. 1  with a calibration cylinder. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     A refrigerant compressor arrangement  1  has a motor  2  with a stator  3  and a rotor  4 , having between them an air gap  29 . The rotor  4  is unrotatably connected to a rotor shaft  5  (also called “crank shaft), having at its lower end an oil pump and at its upper end a crank pin  7 . For reasons of clarity, a casing usually surrounding the refrigerant compressor arrangement  1  is not shown. 
     Via a connecting rod  8 , the crank pin  7  is connected to a piston  9 , which reciprocates in a cylinder  10 . The cylinder  10  is arranged in a mounting sleeve  11 . The cylinder  10  and the mounting sleeve  11  form a cylinder arrangement  12 , which also comprises a cylinder head  13 , which is only schematically shown. 
     A connection between the cylinder arrangement  12  and the motor  2  is realised via a carrier, in the present case comprising a carrier element  14  and a reinforcement element  15 . 
     The carrier element  14  has four flanges  16 , which rest with a bearing surface  17  on a front side of the stator  3 . Flaps  18  being angled in relation to the bearing surface  17 , ensure that the carrier element  14  is undisplaceably held on the stator  3 . The flanges  16  can then be welded onto or otherwise connected to the stator  3 . 
     The carrier element  14  has a cable entry opening  19 , through which an electrical supply cable  20  for the motor  2  is guided. 
     As shown in  FIG. 2 , the reinforcement element  15  forms a pan  21 . In this pan  21 , oil gathers that is pumped upwards by the oil pump during operation and sprayed inside a case, not shown in detail, in which the refrigerant compressor arrangement  1  is located. Through an oil passage  22 , this oil can get into a gap  23  between the carrier element  14  and the reinforcement element  15 , from where it can flow off. This gap  23  is kept open by a spacer  24 , which is formed on the carrier element  14 . 
     The carrier element  14  and the reinforcement element  15  are made as formed sheet metal parts, that is, they are made during one or more working steps by means of punching and bending sheet metal plates. The sheet metal plate used for the carrier element  14  is thinner than the one used for the reinforcement element  15 . 
     The reinforcement element  15  forms a bearing shell  25  for a calotte ring  26 , in which the rotor shaft  5  is supported. The calotte ring  26  has a circumferential surface that forms a part of a spherical surface. The bearing shell  25  has an inner surface, which also forms a part of a spherical surface. The spherical surface of the calotte ring  26  has a somewhat smaller radius than the spherical surface of the bearing shell  25 . The calotte ring  26  is held in the bearing shell  25  by a clamp  27 . The clamp  27  prevents the calotte ring  26  from moving out of the bearing shell  25 . However, it permits a certain tilting movability of the calotte ring  26  in relation to the reinforcement element  15 . 
     As can particularly be seen from  FIG. 2 , the reinforcement element  25  has a trough shaped accommodation  30  for the mounting sleeve  11 . Fixing surfaces  31 ,  32  are located next to the accommodation  30 . The mounting sleeve  11  comprises flanges bent out from its surface. When the mounting sleeve  11  has not yet been connected to the reinforcement element  15 , these flanges can enclose an obtuse angle. When the mounting sleeve  11  is inserted in the accommodation  30  and pressed into the accommodation  30  with a certain force, the flanges align in parallel to the fixing surfaces  31 ,  32 . In this state, the flanges can be connected to the fixing surfaces  31 ,  32  by means of toxing or clinching. Before connecting the flanges to the fixing surfaces  31 ,  32 , the mounting sleeve  11  with the cylinder  10  inside can be displaced in the axial direction within certain limits, so that in this manner a dead space can be set, which will at the end still remain at the upper dead point of the piston  9 . This dead space should be kept as small as possible. 
     The reinforcement element  15  has four projections  36 - 39 , which are located in the accommodation  30 . These projections  36 - 39  are directed towards the cylinder arrangement  12 , when the cylinder arrangement  12  is mounted in the reinforcement element  15 , as shown in  FIG. 1 . 
     In the “raw state”, that is, after manufacturing the reinforcement element  15  and before mounting the cylinder arrangement  12 , the projections  36 ,  37 , which are arranged next to the rotor shaft  5 , have a smaller height than the projections  38 ,  39 , which are located farther away from the rotor shaft  5 . All in all, four projections  36 - 39 , which are arranged in two rows, will be sufficient to support the cylinder arrangement  12  with the required reliability and accuracy in the accommodation  30 , when eventually the cylinder arrangement  12  can be connected to the fixing surfaces  31 ,  32 . 
     In order to provide the desired alignment of the cylinder arrangement  12  in the reinforcement element  15 , a calibration cylinder is used, as shown in  FIG. 3 . The same elements as in  FIGS. 1 and 2  are provided with the same reference numbers. In order to simplify the explanation, the projections  36 ,  38  are arranged in the section level. As can be seen from  FIG. 2 , however, they are actually located a small distance away from the section level in the circumferential direction. 
     As mentioned above, the projections  38 ,  39  are higher than the projections  36 ,  37 . This means that, when the calibration cylinder  40  is inserted in the accommodation  30 , it will tilt, as can be seen from  FIG. 3 . In other words, it has an inclination. 
     The calibration cylinder  40  has a front side  41 , which extends perpendicularly to its axis  42 . Accordingly, as long as the reinforcement element  15  with its projections  36 - 39  has not yet been deformed, a first distance  43  between the front side  41  and the circumferential surface of the crank pin  7  is larger than a distance  44  between the front side  41  of the calibration cylinder  40  and the circumferential surface of the crank pin  7  at the same circumferential position. This circumferential surface  45  of the crank pin  7  extends in parallel to the axis  6  of the rotor shaft  5 . 
     The calibration cylinder  40  is now loaded with a force  46  (symbolized by an arrow). In relation to the axial direction of the calibration cylinder  40 , this force  46  is applied in the area of the projections  38 ,  39 . With a correspondingly large force, these projections  38 ,  39  are deformed. At any rate they are more heavily deformed than the other projections  36 ,  37 . 
     This deformation of the projections  38 ,  39  reduces the inclination of the axis  42  of the calibration cylinder  40 , until it coincides with a straight line  47  that encloses a right angle  48  with the axis  6  of the motor shaft. When the cylinder arrangement is somewhat laterally offset, the straight line  47  can also enclose a right angle with a parallel to the axis  6  of the rotor shaft  5 . 
     The alignment of the calibration cylinder  40  can easily be monitored in that the distances  43 ,  44  are currently compared to each other. As soon as these distances have become the same, the axis  42  of the calibration cylinder  40  extends with the desired alignment, that is, together with the axis  6  of the rotor shaft  5 , or a parallel to that, it encloses a right angle  48 . 
     When now the calibration cylinder  40  is replaced by the cylinder arrangement  12 , also the cylinder arrangement  12  has the desired alignment to the axis  6  of the crankshaft  5 , as the cylinder arrangement  12  and the calibration cylinder  40  have the same outer dimensions. 
     Then the cylinder arrangement  12  can be displaced towards or away from the crank pin  7 , until a dead space formed by the piston  9  and the cylinder  10  as well as the cylinder head  13  has reached a minimum value. 
     While the present invention has been illustrated and described with respect to a particular embodiment thereof, it should be appreciated by those of ordinary skill in the art that various modifications to this invention may be made without departing from the spirit and scope of the present invention.