Abstract:
A spindle of a machining center is equipped with a clutch, which is fitted to a main spindle housing, and directly connected to a power source for separable engagement with a shaft coupling sleeve, and which is guided by sloping guiding trenches of a clutch disk such that a pull rod of the spindle is actuated for a tool shank housing to be changed between a clamped position and a released one; thus, power of the power source can be usually provided to the spindle to effect rotation of the spindle for machining a work piece, and the clutch can be operated for allowing the pull rod to be directly actuated with power of the power source without hydraulic mechanisms.

Description:
BACKGROUND OF THE INVENTION  
       [0001]     1. Field of the Invention  
         [0002]     The present invention relates to a spindle of a machining center, more particularly one, which is structured in such a way that tool releasing and clamping operations can be actuated by means of a clutch, which is connected to the power source, as well as other parts instead of hydraulic mechanisms, and that the number of coil springs used in the spindle can be reduced.  
         [0003]     2. Brief Description of the Prior Art  
         [0004]     Referring to  FIGS. 14 and 15 , a conventional spindle  8  of a machining center includes a spindle seat  81 , a spindle housing  82 , a hydraulic mechanism  84 , a pull rod  85 , a power source  87 , and a main spindle housing  83  fitted in position with the help of both the spindle seat  81  and the spindle housing  82 . Oil passages  841 ,  842  of the hydraulic mechanism  84  are fitted in internal holes  811  of the spindle seat  81  such that a piston  843  can be actuated by means of the hydraulic mechanism  84 , which piston  843  is connected to a ring protrusion  851  of the pull rod  85  at a central hole  844  thereof for making the pull rod  85  move together with it. In addition, a shaft coupling device  86  is connected to an upper end of the spindle seat  81 , and an output shaft  871  of the power source  87 ; the output shaft  871  has a through hole  872 , which communicates with a rotary connecting head  88  arranged at other end of the power source  87  such that cooling water can be supplied through the pull rod  85  when the machining center is in operation.  
         [0005]     From the above description, it can be understood that the hydraulic mechanism  84  is the only mechanism used for actuating the pull rod  85 , and movement of a tool shank housing  89  between a clamping position and a releasing one. And, the hydraulic mechanism is difficult to install, repair, and maintain because the oil passages  841 ,  842  thereof are hidden deep inside the internal holes  811  of the spindle seat  81 . Consequently, the spindle is neither efficient nor convenient to use.  
         [0006]     Furthermore, in order to use the hydraulic mechanism, the spindle has to be equipped with additional hydraulic units and controlling devices whose cost is relatively high. And, oil leaking and staining is likely to happen, and cost of maintenance of the spindle will increase. Moreover, the spindle will stop functioning when power failure or breakdown of the hydraulic mechanism happens accidentally. Therefore, there will be many problems if a hydraulic mechanism is used as power source for actuating the pull rod of the spindle of a machining center.  
         [0007]     Referring to  FIG. 16 , in order to provide enough elastic force and proper clamping force, another conventional spindle  9  of a machining center is equipped with several coiled springs  92  around a pull rod  91  thereof. In the spindle, a push rod  93  is pivoted to an upper end of the pull rod  91 , and a power source is connected to the other end of the push rod  93  so that power of the power source can be passed on to the pull rod  91  through the push rod  93  to effect up and down movement of the pull rod  91 , i.e. to move the pull rod  91  between upper and lower positions, in which positions the pull rod  91  will respectively clamp, and release the tool shank housing. However, because displacement and change of length of each coil springs  92  are too small as compared with the distance of displacement of the pull rod  91 , there have to be many coil springs  92  arranged around the pull rod  91  to be nearly half of the length of the pull rod  91  all together. Consequently, there will be more difficulty in assembling the spindle, noise and less balance in rotation of the spindle therefore the above structure is not suitable for machining centers of high-speed type.  
       SUMMARY OF THE INVENTION  
       [0008]     It is a main object of the present invention to provide a spindle of a machining center to overcome the above disadvantages.  
         [0009]     The spindle of the present invention has a clutch, a main spindle housing, which is directly connected to the clutch at the power input end thereof, and operable with the help of the clutch disk. A claw clutch is directly connected to the power source instead of hydraulic systems for passing on power to the tool shank housing for the same to change from a released position to a clamped position and vice versa; thus, inertia of the whole transmission system of the spindle can be reduced, and it takes less time to accelerate the spindle. There are fewer coiled springs fitted around the pull rod of the present spindle than the pull rods of conventional spindles. Because no hydraulic system is used in the present spindle, there won&#39;t be any disadvantage of hydraulic systems in using the spindle, e.g. waste of power and consumption of extra energy, undesirable effects of high temperature hydraulic oil on machine precision, and cost of maintenance. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0010]     The present invention will be better understood by referring to the accompanying drawings, wherein:  
         [0011]      FIG. 1  is a view of a section of the spindle of a machining center according to the present invention, parallel to the axis,  
         [0012]      FIG. 2  is a first partial cross-sectional view of the spindle according to the present invention,  
         [0013]      FIG. 3  is a view of a first section of the present spindle, perpendicular to the axis,  
         [0014]      FIG. 4  is a partial top view of the present spindle,  
         [0015]      FIG. 5  is a view of a second section of the present spindle, perpendicular to the axis,  
         [0016]      FIG. 6  is a view of a third section of the present spindle, perpendicular to the axis,  
         [0017]      FIG. 7  is a view of a fourth section of the present spindle, perpendicular to the axis,  
         [0018]      FIG. 8  is a view of a section of the parts of the present spindle in  FIGS. 3, 5 ,  6 , and  7 , parallel to the axis,  
         [0019]      FIG. 9  is a second partial cross-sectional view of the spindle according to the present invention,  
         [0020]      FIG. 10  is a view of an end of the present spindle  
         [0021]      FIG. 11  is a view of the present spindle,  
         [0022]      FIG. 12  is a view of the present spindle in operation (in clamping position),  
         [0023]      FIG. 13  is a view of the present spindle in operation (in releasing position),  
         [0024]      FIG. 14  is a first view of the first conventional spindle of a machining center,  
         [0025]      FIG. 15  is a second view of the first conventional spindle, and  
         [0026]      FIG. 16  is a view of the second conventional spindle. 
     
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
       [0027]     Referring to  FIG. 1 , a preferred embodiment of a spindle of a machining center in the present invention includes a spindle seat  1 , a main spindle housing  2 , a clutch  3 , a pull rod  4 , a claw clutch  5 , a cam ring seat  6 , and a guide tube  7 .  
         [0028]     Referring to FIGS.  1  to  3 , the spindle seat  1  has several axial holes, and bearings  11 , and  12  fitted onto the axial holes.  
         [0029]     The main spindle housing  2  is fitted to the bearings  11 , and  12 , and has a cone-shaped hole  21  at a lower end for connection with a tool shank housing  89 . The main spindle housing  2  has a shaft coupling  22 , and a bearing support  23  at an upper end, and has coiled springs  24 , and a moving spacer ring  25  held therein. External spline keys  221  are arranged outsides the shaft coupling  22  for movable connection with internal spline keys  31  of the clutch  3 . In addition, a spacing element  26  is arranged between the shaft coupling  22  and the bearing  11 . The bearing support  23  has a bearing  231  fitted on outer side thereof, and is formed with several cavities  232  therein, to which a spring  233 , and a push rod  234  are fitted. There are thrust bearings  235 ,  251  disposed between an edge of the push rod  234  and an upper edge of the moving spacer ring  25 , which thrust bearings  235 ,  251  are respectively pressed against upper and lower ends of a protrusion  411  of a lower pull rod bolt sleeve  41 .  
         [0030]     The clutch  3  has several cavities  32  formed therein, and several springs  33 , and a push rod  34  are fitted to the cavities  32  such that the push rod  34  is pressed against an upper edge of the spacing element  26  at an edge thereof, and such that the clutch  3  is upwards biased by elastic force. The clutch  3  is formed with upper and lower engaging teeth  35 , and  36  on upper and lower ends thereof such that it can be separably engaged with engaging teeth  131  of a fixing ring  13  fixed on a top of the spindle seat  1  at the lower engaging teeth  36  thereof, as shown in  FIGS. 2, 3 ,  6 ,  11 , and  12 , and such that it can be separably engaged with an engaging claw  51  of the claw clutch  5  at the upper engaging teeth  35  thereof, which claw clutch  5  is fitted to the bearing  231 .  
         [0031]     Referring to FIGS.  1  to  3 , and  5  to  9 , the pull rod  4  has threaded portion  40  at an upper end thereof, on which threads are formed with such shape as to be capable of bearing relatively large force, e.g. trapezoid shape, and which is used for connection with the lower pull rod bolt sleeve  41  as well as an upper pull rod bolt sleeve  42  at a same time. The pull rod  4  is formed with a central hole  43 , through which the guide tube  7  is passed. The upper and the lower pull rod bolt sleeves  42 , and  41  are respectively formed with engaging claws  421 , and  412 , which can engage each other to prevent the upper and the lower pull rod bolt sleeves  42 , and  41  from being displaced relative to each other. The upper pull rod bolt sleeve  42  has a protrusion  422 , and is movably passed into the claw clutch  5  at the protrusion  422 ; the protrusion  422  has several equidistantly spaced insertion pins  423  fitted on an outward side thereof, which is movably passed into straight elongated holes  52  of the claw clutch  5 , and then projected from the claw clutch  5 . A detection ring  424  is securely joined to outward ends of the insertion pins  423 , as shown in  FIGS. 7 and 9 . Furthermore, referring to  FIG. 1 , there is a clamping claw  44  securely joined to a lower end of the pull rod  4 , which clamping claw  44  will change between a releasing position and a clamping position where it clamps the tool shank housing  89  while an inner concave ring  27  of the main spindle housing  2  is up and down moving along the pull rod  4 .  
         [0032]     Besides the straight elongated holes  52  and the engaging claws  51 , the claw clutch  5  has internal spline keys  53 , which can be movably connected with external spline keys  425  of the upper pull rod bolt sleeve  42 . The claw clutch  5  further has a locating ring  54 , and a screw hole  55  on upper side, which is directly connected to a power source  17  or a transmission wheel such that power can be supplied to the claw clutch  5 , as shown in  FIGS. 9, 11 , and  12 .  
         [0033]     Referring to  FIGS. 3, 4 ,  9 , and  10 , the cam ring seat  6  is securely connected to the fixing ring  13  by means of bolts  61 , and arranged outside the clutch  3 . The cam ring seat  6  is formed with several sloping guide trenches  62  therein while a clutch disk  63  is arranged outside the cam ring seat  6 , and equipped with guide wheels  631 , which are passed into the sloping guide trenches  62 . The clutch disk  63  is equipped with a detecting device  64  thereon, and is faced with the upper edge of the clutch  3  at an inner edge  632  thereof, as shown in  FIG. 9 . Moreover, referring to  FIG. 10 , the clutch disk  63  has an ear protrusion  633 , to which an output shaft  651  of a power rod  65  is pivoted. The power rod  65  can be an air cylinder or a power mechanism of linear movement type, and is pivoted to an ear protrusion  14 , which is secured on the spindle seat  1 , at the other end thereof, thus being capable of making the clutch disk  63  rotate ( FIGS. 4 and 9 ) as well as moving up and down to make the clutch  3  change between a first position, wherein the clutch  3  is disengaged from the fixing ring  13  (or the claw clutch  5 ) and a second position, wherein the clutch  3  is engaged with the fixing ring  13  (or the claw clutch  5 ) with the help of the guide wheels  631  and the sloping guide trenches  62 .  
         [0034]     In addition, the spindle seat  1  is equipped with a support unit  15  at an upper portion thereof, and upper and lower detecting devices  151 , and  152  are fitted on the support unit  15  to respectively face upper and lower ends of the detecting ring  424  ( FIG. 2 ).  
         [0035]     Referring to  FIGS. 9, 11 , and  12 , a shaft coupling  16  is securely joined to the locating ring  54  of the claw clutch  5 , and securely connected to an output shaft  171  of the power source  17  such that power of the power source  17  can be directly provided to the claw clutch  5 , thus making the claw clutch  5  rotate as well as rotating the main spindle housing  2  and the tool shank housing  89 , which is secured to the lower end of the main spindle housing  2 .  
         [0036]     The engaging claw  51 , and the internal spline keys  53  of the claw clutch  5  are respectively used for engaging the upper engaging teeth  35  of the clutch  3 , and the external spline keys  425  of the upper pull rod bolt sleeve  42 . When the engaging claw  51  is engaged with the upper engaging teeth  35 , the clutch  3  will rotate together with the claw clutch  5 . On the other hand, when the engaging claw  51  is disengaged from the upper engaging teeth  35 , as shown in  FIG. 12 , the main spindle housing  2  will be secured in position, and the power source  17  will make the upper pull rod bolt sleeve  42  rotate; thus, the lower pull rod bolt sleeve  41  is rotated accordingly, and downwards displaced to push the moving spacer ring  25  as well as to exert force on the coiled springs  24 , and the pull rod  4  is downwards displaced to pull the clamping claw  44 , thus making the clamping claw  44  release the tool shank housing  89  for allowing the tool replacement mechanism of the machining center to operate for tool replacement.  
         [0037]     When the pull rod  4  is downwards displaced, the detection ring  424  will also be pulled to move downwards by the insertion pins  423 , and in turns, the lower detecting device  152  will detect presence of the detection ring  424  owing to contact of the bottom of the detection ring  424  with the lower detecting device  152 . Thus, the power source  17  will stop rotating when the clamping claw  44  releases the tool shank housing  89  completely.  
         [0038]     On the other hand, when the power source  17  is made to rotate in the opposite direction, the upper and the lower pull rod bolt sleeves  42 , and  41  will be turned accordingly, and gradually upwards displaced; thus, the pull rod  4  moves upwards together with the bolt sleeves  42  and  41 , and the clamping claw  44  is pulled upwards to clamp and secure the tool shank housing  89 , which has just been inserted back into the clamping claw  44 . At the same time, the detection ring  424  is upwards moved with the help of the insertion pins  423 , and in turns, the upper detecting device  151  will detect presence of the detection ring  424  owing to contact of the top of the detection ring  424  with the upper detecting device  151 . Thus, the power source  17  will stop rotating in the opposite direction when the clamping claw  44  clamps the tool shank housing  89  securely, as shown in  FIG. 13 .  
         [0039]     Referring to  FIGS. 4 and 10 , when the clutch disk  63  is rotated by means of the power rod  65  pivoted to the ear protrusion  14 , it will be guided to move upwards, and in turns, the clutch disk  63  isn&#39;t pressed against the clutch  3  any longer, and the clutch  3  is upwards displaced by means of the springs  33 . Thus, the lower engaging teeth  36  are separated from the engaging teeth  131  of the fixing ring  13  ( FIG. 9 ), the upper engaging teeth  35  comes into engagement with the engaging claw  51  of the claw clutch  5 , and the detecting device  64  detects presence of the clutch  3  owing to contact of the top of the clutch  3  with the detecting device  64 . Consequently, the power source  17  works to rotate the claw clutch  5 , the main spindle housing  2 , and the pull rod  4 , and in turns, a tool fitted to the tool shank housing  89  is moved accordingly, and a work piece is machined, as shown in  FIGS. 1 and 2 .  
         [0040]     Rotation of the main spindle housing  2  will be stopped after machining of the work piece is finished. And, the clutch disk  63  will be rotated to make the clutch  3  move downwards with the inner edge  632  thereof being pressed against the upper edge  37  of the clutch  3  by means of reverse rotation of the power rod  65 ; thus, the clutch  3  gets back into engagement with the engaging teeth  131  of he fixing ring  13  at the lower engaging teeth  36  thereof, and secured in position. And, the pull rod  4  becomes capable of being pulled for allowing the clamping claw  44  to clamp and release the tool shank housing  89 , as shown in  FIG. 13 . When the clamping claw  44  clamps the tool shank housing  89 , the coiled springs  24  will be compressed by relatively large force, and help the tool shank housing  89  to be securely held in position.  
         [0041]     From the above description, it can be easily understood that the spindle of a machining center of the present invention has advantages as followings:  
         [0042]     1. Because the main spindle housing  2  is directly connected to the clutch at the power input end thereof, and operable with the help of the clutch disk, the claw clutch, which is directly connected to the power source, can pass on power to the tool shank housing for the same to change from a released position to a secured position and vice versa. Consequently, it will save the users time to use the present invention.  
         [0043]     2. Because the tool shank housing is operated with the help of the power source of the spindle of the present invention instead of conventional hydraulic systems, inertia of the whole transmission system of the spindle can be reduced, and it takes less time to accelerate the spindle. Therefore, the present invention is very efficient.  
         [0044]     3. In the present spindle, there are fewer coiled springs used for operating the pull rod than conventional spindles while large elastic force is provided. Therefore, the present invention is easier to assemble.  
         [0045]     4. Because no hydraulic system is used in the present spindle, there won&#39;t be any disadvantage of hydraulic systems in using the spindle, e.g. waste of power and consumption of extra energy, undesirable effects of high temperature hydraulic oil on machine precision, and cost of maintenance.  
         [0046]     5. The pull rod can be effectively and precisely operated whichever position it is in because the spindle seat and the clutch disk respectively have several detecting devices fitted thereon, which can detect both movement and position of the clutch.