DE9411260U1 - Clamping device for shaft tools - Google Patents

Description

Patent attorney's office Tergau & Pohl, Nuremberg

&zgr; 94270-8/37/42

4 Description

Clamping device for shank tools

The invention relates to a clamping device with the features of the upper

of claim 1.

12 The clamping device has a clamping unit for clamping the workpiece in a

13 tool holder. The clamping unit is designed, for example, as an expansion chuck or as a collet insert and clamps the tool shank radially inwards. During operation, the rotating machine tool spindle of the machine tool transmits a torque to the tool shank via the clamping unit.

18 shaft. Normally the friction forces between the clamping unit

ie and the clamped tool shank to allow relative movements between

μ of the machine tool spindle and the tool shank in axial direction and

21 also in the direction of rotation. In extreme applications,

22, where very high torques are required from the machine tool spindle!

23 must be transferred to the tool shank, the clamping force of the

24 Clamping unit is no longer sufficient to prevent relative movements in the direction of rotation between the machine tool spindle and the tool shank.

28 To ensure that the tool shank is securely driven even when the tool

29 sufficient clamping force of the clamping unit, it is

µ DE 39 13 626 A1, a disk-like driver in the clamping device

31 direction. The driver is designed in such a way that it

32 during operation of the machine tool, secured against rotation in the clamping device

33 direction. In this way, the torque is transferred to the

34 drive plate. In order to transfer the torque to the

35 tool shank, the drive plate and the tool shank are connected to one another in a rotationally and axially fixed manner from the outset, i.e. before the tool shank is inserted into the clamping device. In particular, a one-piece connection between the drive plate and the tool shank is required.

8July 1384

Patent Attorney's Office Tergau & Pohl, Nuremberg I ' ·* « &Idigr; · * * ! * * ^ ^eiie ^

&igr; drive disk and the tool shaft. The drive

2 mer disk is arranged radially on the tool shaft. Such, with a miter

3 drive disc combined tool shanks require an increased

4 Manufacturing effort and correspondingly increased manufacturing costs.

5 In order to be able to use such a tool shank, &bgr; a bearing that takes into account the anti-twisting bearing of the drive plate

7 clamping device must be available. The manufacture of the proposed

&bgr; clamping device increases the cost of using the shank tool.

&ogr; shaft tool can also be used in other clamping devices,

10 the drive plate must be laboriously removed from the tool shaft. In

11 Case of one-piece connection between drive plate and tool

12 Separation of both components is not provided for at all.

13 hen. In this case, the shank tool can only be used in the specially designed clamping device of machine tools and is therefore rarely used. The utilization rate of the shank tool therefore remains very low. In the event of any mechanical damage to the tool shank or the

17 Due to the fixed connection, both components are preferably replaced. The necessary replacement of just one of the two components is therefore very expensive.

21 Based on the disadvantages described, the invention has the task

22, the anti-twisting mounting of the tool shank in the tool

23 tool holder. This task is made possible by the

24 multiple combination of claim 1 is solved.

26 The driver and the tool shank are two separate components. The

27 The carrier is mounted on the base of the housing. This ensures that the axial

28 recording still provides sufficient space for the arrangement of a conventional

29 clamping unit is present. Conventional clamping devices can therefore be adapted to the anti-twist 31 drive of the tool shaft according to the invention with little technical effort.

33 For the rotation-proof engagement of the tool shank in the driver,

34 only the axial shaft free end is structurally adapted to the driver

35. Consequently, the rest of the tool shank does not require any structural

36 Adaptation to the driver. The clamping device according to the invention can

37 Therefore, a large number of commercially available shank tools are anti-twist

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Patent Attorney's Office Tergau & Pohl, Nuremberg I * · &iacgr; , · **· Page 3

&igr; more easily. The adjustment of the shaft free end 2 to the driver, which may be necessary for this, can be carried out with little post-processing effort.

4 Regardless of the design of the shaft free end, a

5 Clamping of the tool shank in the conventional manner with proven

&bgr; clamping techniques. The clamping of the tool shank remains

7 therefore remains easy to install and technically simple. The use

β of the driver partially relieves the clamping unit of the task of turning

9 moments to the tool shank. Rather, the

10 clamping unit in the clamping device according to the invention the tool

11 Center the shaft in the tool holder.

is Since the driver is mounted on the base of the housing, it forms an axial

14 Impact surface for the tool shank when inserting it into the tool

15 holder. The driver thus serves in an additional function as a mounting

16 day help. The tool shank is inserted in the usual way in the axial direction into the tool holder. The twist-proof insertion of the shank-18 tool therefore requires more effort from the operator than with conventional

ig clamping devices no additional assembly steps.

21 Claim 2 proposes a possibility that is easy to implement in terms of manufacturing technology.

22 possibility to construct the shaft free end and the driver in such a way

23 so that the tool shank is always secured against rotation

24 is guaranteed.

26 According to claim 3, the centric arrangement of the driver enables the

27 Shank tools can be used rotated by 0° and 180°.

29 According to claim 4, the shaft free end is designed in accordance with the standard. It is

This is an approximately rectangular cross-section in the plane of rotation, which

31 shank-free end forming driving rib. This eliminates the need for

32 any subsequent processing effort for anti-twisting insertion

33 in the driver. Only in the driver must a cross-section of the

34 groove designed as a receiver rib. According to DIN 1809 manufactured

35 Shank tools are offered in large numbers on the market.

se Accordingly, the clamping device according to the invention is provided with structurally

37 adapted driver in a simple manner for a variety of commercially available

38 different shank tools can be used.

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Patent Attorney's Office Tergau & Pohl, Nuremberg ; ·*.&Ggr; *·* J***· ^Page 4

2 According to claim 5, the driver is also within the clamping device

3 easy to install. The driver only has to be moved in the axial direction

4 tion in the tool holder and with its driving shaft in the

5 the tool holder is inserted into the recess. &bgr; the driver shaft fits into the recess in a form-fitting manner. Since on the one hand 7 the cross-section of the recess is usually smaller than that of the

&bgr; tool holder, the holder base serves as a stop surface for the

&bgr; axial displacement of the driver shaft during assembly of the —

10 driver. As soon as the driver hits the receiving base, the

11 Target position of the driver in the final assembly state is reached. In this way,

12 incorrect assembly of the driver is reliably avoided. After reaching

13 Once in its nominal position, the driver only needs to be clamped so that it is secured against rotation and axially immovable within the clamping device. Its immovable bearing in the axial direction also supports the

The tool shank is immobile in this direction.

ie The described bearing of the driver within the clamping device

&iacgr;&ogr; also enables its easy removal from the clamping device

20 maintenance and repair measures are therefore technically simple

21 feasible.

23 According to claim 6, the driver can be easily attached to the

24 The force acting on its clamping edge is secured against accidental axial displacement. The acute angle between the axial direction and the clamping

26 flank ensures that a force component of the clamping element

27 generated clamping force acts in the axial direction and pushes the driver in the direction of the

28 Machine tool presses. A force component opposite to this

29 Force is generated by the carrier being placed on the base. In this way, the carrier remains reliably in its clamped state.

32 If different clamping forces are required in the axial direction depending on the application,

33 force components are required, this is easily achieved by producing

34 driving shafts with clamping flanks of different inclination angles

35 The design and arrangement of the clamping flank and the clamping element not only enable the axially immovable mounting of the driving

37 mers, but also without additional technical measures in rotation

38 on direction of rotation fixing of the driver.

&bgr;.« 1994 ··:·*:·

Patent Attorney's Office Tergau & Pohl, Nuremberg J · II ,· ·**. J Page 5

2 Claim 7 enables a flat contact between the clamping element and

3 the driver shaft of the driver. This also supports a very

4 large clamping force component of the clamping element acting in the axial direction.

e Claims 8 to 10 relate to a very user-friendly clamping element

7 ment. If necessary, it is very easy to replace.

s It is known to provide clamping devices with an axially effective feed device

10 device for the tool shank. Such a feed device is

11 known for example from DE 93 01 918 U1. It is advantageous to use the clamping element

12 ment and the driver according to claims 6 to 10 to be dimensioned so

13 ensure that they can be inserted into the clamping device after removing the axial feed device mentioned above without µ further technical changes.

15 through the clamping device according to the invention for different

ie intended use.

18 Claim 11 proposes a hydraulic expansion chuck as a clamping unit.

19 Such expansion chucks are available in a wide range and have proven themselves in µ use in clamping devices. The tool shank is

21 essential part of its shaft length is fully supported by the expansion chuck.

22. The expansion chuck contains a pressure membrane that presses the tool

23 shaft radially. Due to fluid pressure within the expansion chuck

24 the pressure membrane is pressed radially inwards against the tool shaft

25 and thereby clamps the tool shank.

27 The reducing insert according to claim 12 makes it possible to use the same expansion

28 chuck tool inserts with different shank diameters depending on

29 used reducing insert without always having to for a be-

30 A correspondingly adapted expansion chuck must be available for the correct shaft diameter. With differently dimensioned re-

32 reduction inserts, the clamping device is therefore technically simple and

33 can be adapted to different sized tool shafts at low cost.

34 Pressure membrane of the expansion chuck acts directly radially inwards

35 clamped in. This elastically compresses the reducing insert. se The latter transfers the clamping pressure of the expansion chuck to the tool 37 shank. Assembly is usually carried out in such a way that first the sleeve-like reducing insert is inserted into the tool holder and then the

S. July 1894

Patent Attorney's Office Tergau & Pohl, Nuremberg &Idigr; · * I * · «J Page 6

&igr; tool shank is inserted into the cavity enclosed by the reducing insert 2.

4 According to claim 13, the driver has a larger surface cross-section

5 than the tool shank. This supports the mechanical stability of the

&bgr; driver relative to the tool shank and also the reliable rotation

7 torque transmission of the driver to the tool shank at very large

8 radial cutting force components acting on the shank tool. In

&bgr; Another function is that the driver can be used as a stop surface during assembly.

10 days of reduced use and thus continues to support the

11 easy assembly of the clamping device. Since the driver

12 is mounted immovably in the axial direction in its clamped state, the reducing insert inserted into the tool holder is also improved

&eegr; secured against unwanted axial displacement.

ie According to claim 14, the driver is a

&igr;? Disc. Such a driver is very easy to manufacture.

18 adjustable. The positive adjustment of the disc-like driver to

is the cross-section of the tool holder allows a good guidance of the

μgr; driver during its axial insertion process and thereby supports the

21 user-friendly assembly.

23 The invention is illustrated by an embodiment shown in the accompanying figure.

24 example is explained in more detail.

26 The figure shows a longitudinal axis through the tool holder

27 longitudinal section made by a machine.

29 The tool holder 1 contains on the inner circumference of its receiving mouth

such an expansion chuck 3 of the usual, approximately the above-mentioned standard of

si technology corresponding type. The essence of the expansion chuck 3 consists in

32 of a sleeve-like pressure membrane 4, which is supported by a radially inwardly

33 acting pressure medium radially to the tool axis 5 curved inwards

34 and thereby generates the clamping pressure. In the example, the

35 pressure membrane 4 onto a sleeve-shaped reducing insert 6, which is flush with its outer diameter and which here has the function of an adapter

37. Its inner diameter corresponds to the outer diameter of the

38 tool shank 7, which in the embodiment is assigned to a milling cutter

July 8, 1994

Patent Attorney's Office Tergau & Pohl, Nuremberg J ·*< >· · ·* 5 '· · Page 7

&igr; is. The design of the tool is similar to DIN 1809. In the area of the back

2 overwhelming end facing the machine tool 8 is the tool holder

3 would take 1 over its circumference filled by a driver 9, which here the

4 Form of a driving disc with the tool axis 5 as driving axis

5. The outer diameter of the drive plate 9 corresponds to the

&bgr; Inner diameter of the tool holder 1. The drive plate 9 is in

7 Axial direction 21 on the base 10 of the tool holder 1. Ma-

8 On the rail side, the drive plate 9 carries a tool axis 5 co-

9 axial driver shaft 11, which extends into the inner bore

10 recess 12 of a machine tool spindle 13. The

11 Machine tool spindle 13 forms the housing of the clamping device. The

12 Diameter of the recess 12 is smaller than the diameter of the tool

13 tool holder 1.

ie The driver shaft 11 is provided on its circumference with a clamping notch 14 for

The loading is provided by a clamping screw 15. The flanks of the

&igr;? clamping notch 14 are placed so that their side facing the machine tool 8

is clamping flange 16 an acute angle 17 opening towards the machine with

19 of the tool axis 5. By applying the clamping edge 16

μgr; on the side of the clamping screw 15, the drive disc 9 is moved in the clamping direction

21 18 to the machine tool 8 with the result that the

22 Drive disc 9 fits snugly against the receiving base 10.

24 The drive plate 9 carries on its side facing the tool shank 7

25 surface extending radially over practically its entire diameter.

26 extending driver groove 19 for the positive enclosing of the

27 shank free end of the tool shank 7 with standard arranged centers&mdash;

28 slave rib 20.

3o The driver 9, which is clamped by the clamping screw 15, is a rotationally fixed and

si can be positioned precisely within the machine tool spindle 13

32 tioned molded part, which keeps the tool in place even under extreme load peaks.

33 zen against twisting and pulling out of the tool holder 1.

34 Such stress peaks can exceed 10 times the normal value.

35 Therefore, the expansion chuck according to the invention is particularly suitable for clamping milling cutters made of solid carbide for the realization of

37 their longer service life. The invention enables extreme cutting

38 utilizing the functional advantages of expansion chucks.

8.JuI11894

Patent Attorney's OfficeTergau & Pohl, Nürnlj^rg.··, _# ·· ·.·· .. . Page

&igr; the essential functional parts: driver 9 and clamping screw 15 so

2 designed and dimensioned so that they can be fitted without structural changes to

3 a conventional, equipped with an expansion chuck and additionally

4 equipped with an axial feed device according to DE 93 01 918 U1

5 machine tool spindle 13 can be used.

Patent attorney's office Tergau& Pohl, Nuremberg* * Il .* Ji;.

List of reference symbols

1 tool holder

2 receiving mouth

3 expansion chucks

4 Pressure membrane

5 Tool axis

6 Reduction insert

7 Tool shank

8 Machine tool

9 Carrier

10 Supporting base

11 Drivership

12 Recess

13 Machine tool spindle

14 clamping notch

15 Clamping screw

16 Clamping flank

17 acute angle

18 Clamping direction

19 Driving groove

20 Driving rib

21 Axial direction

Claims (1)

Patent Attorney Office Tergau & Pohl, Nümbe/g ., _t Page 1 &igr; 94270-8/37/42 3 8 July 1994 &bgr; Claims 9 1. Clamping device of a machine tool (8) for a rotating shaft 10 tools, 11 - with a central holder (1) for axial insertion of the shaft tool 12 witnesses, is - with a clamping unit radially surrounding the tool holder (1) for &eegr; clamping of the tool shank (7) and is - with a in axial direction (21) outside the clamping unit in the The tool holder (1) has a storable driver (9) for anti-twisting fixing. 17 Fixing of the shank tool, is characterized by 19 - that the driver (9) on the base (10) is secured against rotation and axially is mounted so immovably, and 21 - that the tool shank (7) during the axial insertion process with 22 engages its axial shaft free end in the driver (9) in a rotationally secure manner. 24 2. Clamping device according to claim 1, 25 characterized by 26 that the shaft free end 27 - a tool shaft (7) axially projecting in the direction of rotation 28 polygonal driving rib (20), and 29 - engages positively in a groove (19) of the driver (9). si 3. Clamping device according to claim 2, 32 characterized by 33 a centric arrangement of the driving groove (19). 35 4. Clamping device according to claim 2, se characterized by 37 that the tool shank (7) and its driving rib (20) similar to DIN 1809 are trained. &bgr;. Jutl 1994 (&Ngr;:\&Agr;&Ngr;\94270.&Tgr;&KHgr;&eegr; ····"" Patent Attorney Office Tergau & Pohl, Nuremberg Page 2 a 5. Clamping device according to one of claims 1 to 3, 3 characterized by 4 that the driver (9) is connected to a &bgr; driver shaft (11) running in the axial direction {21), soft 6 - a form-fitting, coaxially connected to the receiving base (10) 7 passes through the recess (12) of the clamping device aligned with the tool holder (1) and a - can be clamped immovably in the axial direction. 11 6. Clamping device according to claim 5, 12 characterized by 13 - that in the housing of the clamping device an externally operated &eegr; Clamping element for clamping the driver shaft (11) movable is inserted, and ie - that the driver shaft (11) has at least one 17 has a recess which acts as a clamping notch (14) and whose 18 element to be loaded in the direction of the machine tool (8) is clamping flank (16) together with the axial direction (21) a pointed, 20 and encloses an angle (17) opening towards the machine tool (8). 22 7. Clamping device according to claim 6, 23 characterized by 24 that the clamping element in the housing of the clamping device is approximately radial to the 25 Driving shaft (11) is guided in motion and is provided with a 26 The end face facing the shaft (11) runs parallel to the clamping flank (16). 28 8. Clamping device according to claim 7, 29 characterized by µgr; that the clamping element is a clamping screw (15), si - whose external thread for movement guidance fits into an internal thread of the 32 housing of the clamping device, and 33 - whose inner face facing the driver shaft (11) is designed to act 34 impact of the clamping flank (16). 8. JuI11994 (&Ngr;&Lgr;&Agr;&Ngr;\94270.&Tgr;&KHgr;&eegr; Patent Attorney Office Tergau & Pohl, Nuremberg ., Page &igr; 9. Clamping device according to claim 8, 2 characterized by 3 that the axis of rotation of the clamping screw (15) is arranged perpendicular to the surface of the * clamping flank (16). 6 10. Clamping device according to one of claims 6 to 9, 7 characterized by &bgr; that the clamping element is on its side opposite the driver shaft (11) 9 front side a recess for the positive reception of a 10 operating tool, e.g. a socket wrench. 12 11. Clamping device according to one or more of the preceding 13 sayings, &eegr; characterized by is that the clamping unit is a hydraulically acting expansion chuck (3). 17 12. Clamping device according to claim 11, is characterized by ig that a sleeve-like, flush in the tool holder (1) and a reducing insert (6) which can be elastically compressed by the expansion chuck (3) 21 positively encloses the inserted tool shank (7). 23 13. Clamping device according to claim 12, 24 characterized by 25 that the driver (9) 26 - in the plane of rotation a larger cross-section than the tool shank (7) 27, and 28 - with its radially projecting tool shank (7) 29 surface area serves as a stop surface for the µ face of the reducing insert (6) facing the driver (9). 32 14. Clamping device according to one or more of the preceding 33 sayings, 34 characterized by 35 that the driver (9) has a circular, form-fitting in the tool holder 36 take (1) inserted disc is. July 8, 1994 (&Ngr;&Lgr;&Agr;&Ngr;\94270.&Tgr;&KHgr;&eegr;