Abstract:
A balancing or measuring adapter, which includes a main body having a holder for the component to be balanced or measured and a clamping device assigned to the main body having a movable clamping element for clamping the component to the main body and releasing it therefrom. A braking device for generating a constant advance speed of the clamping element as it moves is arranged on the movable clamping element for precisely positioned clamping and jerk-free release of the component.

Description:
FIELD OF THE INVENTION 
     The invention relates to a balancing or measuring adapter and to a balancing or measuring machine having such a balancing or measuring adapter. 
     BACKGROUND OF THE INVENTION 
     Such balancing or measuring adapters are used for clamping a rotating component onto a balancing and/or measuring machine. A balancing machine having a balancing adapter of the type in question is known from DE 299 80 181 U1. It contains a main body having a centered receiving opening for the component to be clamped and a collet actuating unit, movable relative to the main body, for a collet chuck. In this known design, the collet chuck is fixedly mounted on the main body and is not movable axially relative thereto. The clamping tongues of the collet chuck are movable between a clamping and a release position by axially displacing the collet actuating unit. Additional centering elements, by which the components to be measured or balanced can be pre-tensioned radially, are often provided in the receiving opening region. In order to be able to release the clamped components after balancing or measurement, it also is necessary for the collet actuating unit to overcome the additional forces applied by the centering elements. For this purpose, the forces of the collet actuating unit must be increased, which can lead to jerky movements of the collet actuating unit. Since the axial movement of the collet actuating unit is generally also used to press the component out of the balancing or measuring adapter, there can be an undesired abrupt ejection of the components to be balanced or measured from the main body. This is particularly the case if the ejection is accomplished with compressed air. 
     SUMMARY OF THE INVENTION 
     A balancing or measuring adapter that enables an accurately positioned clamping and shock free release of a component is disclosed. 
     Expedient improvements and advantageous embodiments of the invention are also disclosed. 
     In the balancing or measuring adapter according to the invention, a braking device for producing a constant advance speed of the clamping element during movement thereof is arranged on the movable clamping element. Thereby abrupt movements of the clamping element and uncontrolled ejection movements caused thereby can be avoided. Kinetic energy can be absorbed by the braking device and the collision speed of the clamping element during ejection of the components to be balanced or measured can be reduced. Bounce-back of the moved masses can also be avoided. 
     In a particularly expedient embodiment, the braking device can comprise one or more fluid brakes arranged with a distance between one another in the circumferential direction, each having a brake piston movable inside a holder. The fluid brakes can preferably be designed as hydraulic dampers with a hydraulic fluid as the brake fluid. 
     In an embodiment with an advantageous design, the braking device can be arranged between the main body and an actuating piston of the clamping device. The braking device could also be arranged between the actuating piston and an additional actuating element associated with the clamping element, however. 
     In a simple and advantageous embodiment, the brake piston can be axially displaceable inside a holder constructed as a bore and is sealingly guided by a radial seal. The holder, formed as a bore, can be arranged in the actuating piston and the brake piston can be arranged on the main body. It is also possible, however, to provide the brake piston on the actuating piston and the associated holder on the main body. 
     In another possible embodiment, however, the brake piston can be arranged displaceably in a holder constructed as a hollow cylindrical outer body and contain an outward-projecting piston rod. The lower end of the piston rod can engage via an end button with bores on the upper side of the actuating piston. 
     The outer body can be arranged in corresponding axial bores of a lower part of the main body and be supported at the upper end on the underside of an upper part of the main body. 
     The fluid brakes expediently contain a through-opening arranged inside the piston for connection to two chambers filled with a fluid. When a force is applied to the fluid brake, the fluid must flow through the through-opening. The resulting static pressure produces the opposing force required for movement control. 
     In another advantageous embodiment, at least one centering element for centric mounting of the component inside the main body is inserted into the holder. Thereby it is possible to achieve a precisely positioned and centered accommodation of the component inside the main body. 
     In one possible embodiment, for example, the clamping device can comprise a collet chuck and an axially displaceable clamping element for actuating the collet chuck. In a simple embodiment, however, the clamping device can also be constructed as a threaded rod for engagement with the component to be balanced or measured. Other suitable clamping devices for centered clamping are also conceivable. The clamping element can contain a rod-like guide region, by which the clamping element is displaceably mounted in the main body via a bearing sleeve. The clamping element can contain an actuating head, on which an outer conical surface and a cylindrical region having a cylindrical outer surface for contact with clamping tongues of the collet chuck are provided. 
     The invention further relates to a balancing or measuring machine containing a balancing or measuring adapter having the above-described features. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       Additional details and advantages of the invention emerge from the following description of preferred embodiments with reference to the drawings. In the drawing: 
         FIG. 1 : shows a longitudinal section of a first embodiment of a balancing or measuring adapter according to the invention in a clamped position; 
         FIG. 2 : shows a longitudinal section of the balancing or measuring adapter from  FIG. 1  in a release position; 
         FIG. 3 : shows a longitudinal section of a second embodiment of a balancing or measuring adapter according to the invention in a clamped position; and 
         FIG. 4 : shows a longitudinal section of the balancing or measuring adapter from  FIG. 3  in a release position. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     The balancing or measuring adapter  1  shown in a clamped and a release position in  FIGS. 1 and 2  is conceived for clamping a rotating component  2  on a balancing or measuring machine. Centered, highly precise and repeatable holding of the component  2  to be balanced or measured is of particular importance in such machines. The balancing or measuring adapter  1  contains a main body, which can be inserted into the drive spindle of the balancing or measuring machine, for example, and which consists in the illustrated embodiment of a hollow cylindrical upper part  4  furnished with a flange  3  and a lower part  5  screwed onto the upper part. The main body can be mounted on the upper side of the drive spindle by means of the flange  3 , for example. 
     The upper part  4  has a holder  6 , formed as an opening for a shaft  7  of the component  2  to be clamped, and a lower passage area  8 . The holder  6  can also be designed as a flat support or the like. The component  2  can be a tool holder for a drilling, milling or grinding tool, a rotor or some other machine part to be balanced or measured. The shaft  7  is shaped conically and can have a polygonal, circular or other suitable cross section. The holder  6  in the upper part  4  is conical and has an inner contour matched to the cross section of the shaft  7 . A centering element  9  constructed as a clamping ring, for example, for centered mounting of the component  2  in the main body is inserted into the holder  6  in the upper part  4 . 
     A collet chuck  10  and a clamping element  11  coaxial with the collet chuck are arranged in the main body, composed of the upper part  4  and the lower part  5 , in order to actuate the collet chuck  10 . The collet chuck  10  has a sleeve-like socket  12  and a plurality of radially resilient clamping tongues  13  separated from one another by axial slots, along with a clamping region  14 , formed as a thickened portion, at the free, anterior end of the clamping tongues  13  facing the component  2  to be clamped. At the clamping region  14 , the clamping tongues  13  have an inner contact surface  15  for contacting the actuating element  11 , and an outer contact surface  16  for contacting an inner opposing surface  17  on the inner side of the shaft  7  of the component  2 . The collet chuck  10  is mounted in an annular grove  18  of the lower part  5  by means of the sleeve-like socket  12 , with the aid of bolts that are not shown. 
     The clamping element  11  contains a lower, rod-like guide region  19  and an upper actuating head  20  that comprises an outer conical surface  21  and a cylindrical region  22  therebelow having a cylindrical outer surface  23 . The clamping element  11  is guided by the rod-like guiding region  19 , via a bearing sleeve  24  provided with rolling bodies, so as to be movable axially in a through-bore  25  in the lower part  5  of the main body. An actuating piston  26  is mounted with the aid of a bolt  27  at the end of the rod-shaped guidance area  19  protruding downward relative to the lower part  5 . By means of the clamping element  11 , the elastically resilient clamping tongues  13  of the collet chuck  11  are movable between a clamped position shown in  FIG. 1  and a release position shown in  FIG. 2 . 
     Compression springs  28  that are visible in  FIG. 1  are tensioned between the lower part  5  and the piston  26 . For stable retention, the compression springs  28  are inserted into blind holes, not visible, in the lower part  5  and in the piston  26 . The clamping element  11  is pressed by these compression springs  28  into the clamped position shown in  FIG. 1 . By displacing the actuating piston  26  against the force of the compression springs  28 , the actuating element  11  can be pushed from the clamping position shown in  FIG. 1  into the release position shown in  FIG. 2 . For this purpose, the actuating piston  26  can be movably arranged, sealed via a radial seal, in the drive spindle of the balancing or measuring machine and can be impinged upon from the lower side with compressed air. 
     A braking device  29  having a plurality of fluid brakes with a distance between one another in the circumferential direction is additionally arranged between the lower part  5  of the main body and the actuating piston  26 . The fluid brakes have a radially sealed brake piston  31  guided inside a receptacle  30 . In the embodiment shown, the brake pistons  31  are displaceable, sealed by means of radial seals  32 , in receptacles  30  formed as bores in the upper side of the actuating piston  26 , facing the lower part  5 . The brake pistons  31  contain a first chamber  34  sealed by a cover  33  and are fastened to the underside of the lower part  5  with the aid of bolts  35  facing downward via the cover  33 . A second chamber  37  is delimited between a bottom  36  of the brake piston  31  and the receptacles  30  constructed as bores. A through-opening  38  for connecting the first chamber  34  to the second chamber  37  is provided in the bottom  36  of the brake piston  31 . 
     The operation of the above-described balancing or measuring adapter will be explained below with reference to  FIGS. 1 and 2 . 
     The balancing adapter  1  is shown in the clamped position in  FIG. 1 . In this position, the clamping element  11  is pressed downward via the compression springs  28  tensioned between the actuating piston  24  and the lower part  5 . By means of the outer conical surface  21  on the upper actuating head  20  of the clamping element  11 , the clamping regions  14  at the upper, free ends of the clamping tongues  13  are pressed radially outward, so that the outer clamping surfaces  16  come into contact with the inner mating surface  17  on the inner side of the shaft  7  and pull it into the holder opening  6 . 
     By applying pressure to the actuating piston  26  with compressed air or some other pressure fluid, the clamping element  11  can be pressed upward against the force of the compression springs  28  into a release position shown in  FIG. 2 . The clamping regions  14  of the clamping tongues  13  can also come into contact at their inner contact face  15  with the cylindrical outer surface  23  on the cylindrical region  22  of the clamping elements  11 . Because the clamping element  11  has a larger diameter in the upper conical region  20  than in the cylindrical region  22  arranged thereunder, the front clamping regions  14  of the collet chuck  13  can tilt radially inward and release the component  2  for removal or insertion into the balancing adapter  1 . The clamping element  11  has, at the upper end thereof, an upper end face  39 , which comes into contact with an interior flat surface  40  in the release position shown in  FIG. 2 , and presses out the component  2 . 
     When the brake piston  31  extends into the receptacles  30  formed as bores, the pressure fluid present in the chamber  37  is displaced via the through-opening  38  into the chamber  34 . The resulting static pressure produces the opposing force required for controlling the advancing movement. A constant advancing speed of the collet actuating unit over the stroke thereof can be achieved with the aid of the braking device  29 , and thereby an abrupt outward movement of the clamping element  11  can be avoided. Even in the event of a sudden application of pressure to the actuating piston  26 , the clamping element  11  moves at a constant speed, so that an abrupt impact of the clamping element  11  on the component  2  at a high collision speed and the resulting uncontrolled ejection of the component  2  can be avoided. 
       FIGS. 3 and 4  show another embodiment of a balancing or measuring adapter  1 . This embodiment corresponds in its basic structure and mode of operation to the embodiment in  FIGS. 1 and 2 , and therefore corresponding components are provided with the same reference numbers. Here too, a collet chuck  10  having a plurality of radially resilient clamping tongues  13  is arranged in a main body composed of an upper part  4  and a lower part  5 . The clamping tongues  13  are movable between a clamping and a release position by a collet actuating unit  11  associated with the collet chuck  10  and by an actuating piston  26 . Compression springs  28  that are visible in  FIG. 1  are tensioned between the lower part  5  and the piston  26 . The actuating element  11  is pressed by these compression springs  28  into the clamped position shown in  FIG. 3 . A braking device  29  having a plurality of fluid brakes distributed uniformly in the circumferential direction is also present in this embodiment. 
     Differing from the embodiment of  FIGS. 1 and 2 , the fluid brakes here have a holder  41  constructed as hollow cylindrical outer body and an axially movable outward-projecting piston rod  42  therein. The outer body  41  is arranged in corresponding axial bores  43  of the lower part  5  and is supported at its upper end on the underside of the upper part  4 . The lower end of the downward-projecting piston rods  42  engages via an end button  44  with bores  45  on the upper side of the actuating piston  26 . Here too, a constant advancing speed of the collet actuating unit is achieved by means of the fluid brakes. 
     The invention is not limited to the embodiment described above and illustrated in the drawings. Thus different braking elements for producing a constant advancing speed of the clamping element can be provided. In addition, the clamping system can be used analogously also for clamping processes in which the radial clamping movement progresses from the outside to the inside.