Abstract:
A vane groove grinding apparatus for compressor cylinder including a compressor cylinder holding means the compressor cylinder being provided with an inner hole and a vane groove extending radially outwardly from the inner hole, sliders being movable along a center line of the inner hole and at a right angled direction to the vane groove, a grinding disk holder facing one open side of the inner hole and a support for locking the holder facing another open side of the inner hole both being disposed on a slider adjacent to the compressor cylinder, when the grinding disk is inserted in the vane groove a distal end of the grinding disk holder is firmly engaged in the support.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates to a vane groove grinding apparatus for a compressor cylinder containings an inner hole and a vane groove extending radially outwardly from the inner hole. 
     FIG. 8 is a perspective view showing a conventional vane groove grinding apparatus in which a compressor cylinder  1  held in the shown position by a holding means (not shown) has an inner hole  2  (center line: O 1 ) and a vane groove  3  extending radially outwardly from the inner hole. In the inner hole  2 , a holder  5  and a thin cylindrical inside grinder  6  are inserted, the holder  5  being attached on the left end of a grinding apparatus, a right end of the grinder  6  being connected to a spindle  7  and the left end of the grinder  6  being rotationally received by the holder  5 . While keeping the grinder  6  in high speed rotation by the spindle  7 , when the body  4  is driven in the direction of arrow X 1  together with the grinder  6 , the grinder  6  grinds one surface of the opposing surfaces of the groove  3 , and when the body  4  is driven in the reverse direction from arrow X 1 , the grinder  6  grinds another surface of the opposing surfaces of the groove  3 .  8  is an open space. Generally in the vane type compressor, the cylinder  1  is covered by side housings from both sides, and a rectangular vane plate in the groove  3  contacts on the outer surface of an eccentric rotor (not shown). 
     But, according to the above grinding system, abrasion on the grinder  6  differs at places of different distances from its proximal end, which causes the deterioration of plane degree (accuracy) and parallel degree (accuracy) of the opposing surfaces of the groove  3 . In addition, due to the small diameter of the grinder  6 , its grinding speed on the surface and its rigidity are inevitably low, these disadvantages increase as the width of the groove gets small. 
     In a disk grinding system shown in FIG. 9, a grinding disk  10  supported by a bar-shaped holder  9  and driven in the direction of arrow X 2  by way of a drive force transmitting means installed inside the holder  9 , grinds one surface of the opposing surfaces of the groove  3  when the holder  9  moves to the left in the direction of arrow X 2 , and grinds another surface of the groove  3  when the holder  9  returns in the reverse direction to the position of FIG.  9 . 
     But, according to the grinding system of FIG. 9, since the projecting distance of the holder  9  varies as the grinding process proceeds and the holder  9  is a cantilever the plane degree and parallel degree of the opposing surfaces of the groove  3  are inevitably unstable. In addition, it is difficult to change the grinding disk, in that it is necessary to change the grinding disk  10 , belts, bearings and the like. 
     SUMMARY OF THE INVENTION 
     An object of this invention is to improve manufacturing accuracy, especially for plane degree and parallel degree, and manufacturing efficiency. A first embodiment is a vane groove grinding apparatus for a compressor cylinder comprising a compressor cylinder holding means, the compressor cylinder being provided with an inner hole and a vane groove extending radially outwardly from the inner hole, sliders being movable along a center line of the inner hole and along a right angled direction to the vane groove, a grinding disk holder facing one open side of the inner hole and a support for locking said holder facing another open side of the inner hole both being disposed on a slider adjacent to the compressor cylinder, when the grinding disk is inserted in the vane groove a distal end of the grinding disk holder is firmly engaged in the support. 
     A second embodiment is a vane groove grinding apparatus as described above, in which the compressor cylinder holding means is an index table being provided with a plurality of working stations at regular intervals with clampers. 
     A third embodiment is a vane groove grinding apparatus of the type of the first embodiment, in which one of the engaging portions of the holder and support is a wedge shaped projection and another portion is a wedge shaped slot. 
     A fourth embodiment is a vane groove grinding apparatus of the type of the first embodiment, in which the sliders are composed with combined plural sliders. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a partially sectional elevational view of the inventive vane grinding apparatus during the grinding operation. 
     FIG. 2 is a schematic sectional view taken on the line II—II of FIG.  1 . 
     FIG. 3 is a schematic sectional view taken on the line III—III of FIG.  1 . 
     FIG. 4 is a partially enlarged view of FIG.  1 . 
     FIG. 5 is a partially enlarged view of FIG.  2 . 
     FIG. 6 is a partially enlarged view of FIG.  3 . 
     FIG. 7A, FIG.  7 B and FIG. 7C are views corresponding to a part of FIG. 5 to show various modified constructions. 
     FIG. 8 is a perspective view showing a prior art construction. 
     FIG. 9 is a perspective view showing another prior art construction. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     In FIGS.  1 ˜ 3  showing the first embodiment of the present invention, like member as in FIG.  8  and FIG. 9 show like or corresponding elements. On a base  14  in FIG. 1, a back-and-forth slider  16  is supported through a rail  15  extending back-and-forth direction, i.e. at a right angle to the paper of FIG. 1. A female screw thread  17  supported on the under surface of the back-and-forth slider  16  is threadedly engaged with a lead screw  18  through balls (forming a ball screw) the lead screw  18  being connected to an output shaft of an AC servomotor (both not shown) attached to the base  14 . Therefore, by driving the back-and-forth slider  16  back-and-forth i.e. in a direction at right angles to the paper of FIG. 1, a grinding disk  11  moves to the surfaces of the vane groove  3  at a right angle, which permits a predetermined depth of cut to the opposite surfaces of the vane groove  3 . 
     On the back-and-forth slider  16 , a right-left slider  21  is supported through a rail  20 , and the right-left slider  21  is Connected to an AC servomotor  22  through another ball screw mechanism (not shown) to move right and left, the AC servomotor  22  being attached to the back-and-forth slider  16 . 
     An up-and-down slider  25  is supported on a vertical rail  24  of the right-left slider  21 , the up-and-down slider  25  being connected to an AC servomotor  26  through another ball screw mechanism (not shown) to move up-and-down, the AC servomotor  26  being mounted on top of the right-left slider  21 . 
     In an indented portion  28  formed on the right hand side surface middle part of the up-and-down slider  25 , a left end part of an index table  30  of an index machine  29  enters in. A base  31  is mounted on the right hand side surface of the up-and-down slider  25  above the indented portion  28 , and the base  31  is provided with a motor  32  and a grinding disk holder  33 , an output pulley  34  of the motor  32  being connected to a pulley  36  through a timing belt  35 , a gear  38  fixed on an axle  37  also fixed on the pulley  36  being meshed with a gear  39  (see FIG. 5) formed outside the periphery of the grinding disk  11 . Two wedge shaped projections  40  formed on the lowest ends of the holders  33  are engaged with a wedge shaped concave slot formed on the top end of the support  41 , the engaged point being inside a hole  43  formed in the index table  30 . 
     The support  41  is guided to move up and down on a vertical rail  45  attached to the right hand side surface of the up-and-down slider  25 , a lowest end of the support  41  being connected to a rod  47  of an oil hydraulic cylinder  46  attached to the up-and-down slider  25 . 
     In an upper periphery of the hole  43  of the index table  30 , a C shaped spacer ring  49  is engaged with its slit  49   a  to be oriented to the right in FIG. 1 (i.e. to the side of the center of the index table  30 ). On the spacer ring  49 , the cylinder  1  is disposed with its vane groove  3  located just on the slit  49   a , and the cylinder  1  is clamped by a pair of arms  50   a  of a damper  50  (an example of holding means). As the vane groove  3  of the cylinder  1  is located near the side of table center from the hole  43 , a moment to the index table  30  due to the grinding force acting at a right angle on one of the opposed surfaces of the vane groove  3  during the grinding process decreases, which makes it easy to keep the index table  30  stationary and firmly, and to increase the manufacturing accuracy. In FIG. 2,  51  is an oil hydraulic (clamping) cylinder fixed on the index table  30 , and  52  is a clamping nut engaged on top of the rod projecting upward from the cylinder  51 . On the index table  30 , as shown in FIG. 3, there are working stations such as a loading-unloading station P 1 , a grinding station P 2  and a measuring station P 3  indexed on a circle at regular intervals. When a workpeice is clamped, arms  50   a  directing to the table center as shown in the loading station P 1  in FIG. 3 are rotated to the direction of the center of the cylinder as shown in the grinding station P 2 , then forced downward to clamp the work (cylinder  1 ). When a work is unclamped, arms  50   a  positioned on a circle as shown in measuring station P 3  are forced upward to unclamp and are rotated to direct the center of the index table  30  as shown in the unloading station P 1 . 
     FIGS. 4,  5 ,  6  are partially enlarged views of FIGS. 1,  2 ,  3  respectively. As clearly shown in the FIG. 5, the grinding disk  11  is formed of a circular steel plate with a gear  39  on the periphery and grinding layers  55  (membrane, thin plate etc.) such as CBN on both sides. A central axle bolt  56  is supported in holes  58  of halved holders  33  through a bearing  57 . The grinding layers  55  are opposed to indented portions  54  through slight clearances.  59  is a nut,  60 , 60  are covers and  61  is a bolt. As shown in FIG. 4, the grinding disk  11  is mounted as exposed more to the right from the holder  33 , by which the grinding layers  55  of the grinding disk  11  are able to cover or grind each of the whole opposed surfaces of the vane groove  3  while moving up and down, and allow the gear  39  to project in the open space  8 . 
     Although FIG. 1 shows the state of the grinding operation going on, prior to the grinding operation, the support  41  is lowered to the position  41 ′, the up-and-down slider  25  is raised to the position  25 ′, thus-keeping the support  41  below the hole  43 , as well as the holder  33  above the inner hole  2  and above the damper  50 , rotating the index table  30  to the arrow as shown in the FIG.  3  and indexing a non ground cylinder  1  to the grinding station P 2 . Then the right left position of the right-left slider  21  is fixed as the grinding disk  11  to take the position of FIG. 1 or FIG.  6 . The motor  32  is kept running. As the holder  33  is lowered, the support  41  is raised which causes the wedge shaped projections  40  being engaged with the wedge shaped slot  42  as shown in FIG.  1 . The up-and-down slider  25  repeats up and down motion giving gradual cut to one of the opposed surfaces of the vane groove  3  by the back-and-forth slider  16 , and when a determined cut is given, the other surface is ground in the same way. When the grinding operation ends, the slider  25  is raised to  25 ′, the support  41  is lowered to  41 ′, and the index table  30  is rotated to the arrow of FIG. 3 by 120 degrees keeping the cylinder  1  free from the up-and-down slider  25  and support  41 . By that time, loading and unloading are finished at the station P 1 , and measuring is finished at the station P 3 . 
     As shown in the FIG. 7A, in case a radial depth of an open space  8 a is small and it is difficult to provide a gear  39  on a grinding disk as shown in FIG.  1  and FIG. 5, a grinding disk  11   a  without a gear and an adjacent gear  65  may be combined in a body by spring pins  66  for example, the gear  65  being driven by way of an idle gear (not shown) which is supported in the holders  33 . According to the construction, the grinding disk  11   a  which needs repair exchange periodically becomes simple in structure to avoid or decrease the exchange, and presents a lower operation cost. 
     Instead of the gear  65 , a pulley  68  (FIG. 7B) may be employed and the pulley  68  may be driven by a belt with a circular cross section, a timing belt or the like. In that case, the same effect as in FIG. 7A may be expected. 
     In place of a pulley  68 , a bevel gear  69  (FIG. 7C) may be employed and the bevel gear  69  is engaged with a bevel pinion  70  which is supported by holders  33 , the bevel pinion  70  being driven through a cable (not shown). In this case, the driving mechanism gets compact and the manufacturing cost decreases. 
     Besides, in place of the wedge shaped projections  40  and wedge shaped slot  42 , a conical projection and a conical indented portion may be employed. According to that variation, a binding of the right-and-left direction is accomplished as well as a binding of the to-and-fro direction, resulting in a high manufacturing accuracy and lower manufacturing cost. On the other hand, the wedge shaped projection  40  and the wedge shaped slot as shown assures a position holding rigidity of the to-and-fro direction of the grinding disk  11 ,  11   a , and accurate distance, parallel degree and plane degree of the opposing surfaces of the vane groove  3 . The halved holders  33 , 33  shown in FIGS. 2 and 5 assure simple assembling. 
     According to the first embodiment, since the lowest end of the holder  33  is firmly confined by the support  41  while the vane groove  3  is ground by the reciprocating up-and-down slider  25 , i.e. the grinding disk  11  is supported at both upper and lower sides not like a cantilever, a stable support is accomplished improving the plain degree and parallel degree of the vane groove surfaces great deal. 
     According to the second embodiment, an accurate working position is provided and a high grinding efficiency is expected. 
     According to the third embodiment, the lower end of the holder  33  is firmly bound by the support  41 . 
     According to the fourth embodiment, back-and-forth, right-and-left, up-and-down movements of the grinding disk  11  get stable and easy, and guiding mechanisms also get simple.