The invention relates to bevel gear cutting tools (bevel gear milling tools) for milling bevel gearings and the use of such tools in soft- and hard gear cutting.
The priority of the German utility model deposition DE 20 2007 007 063.2 is claimed, which was deposited on 16 May 2007 under the title “KEGELRADFRASWERKZEUG MIT FRASSCHNEIDPLATTEN” (BEVEL GEAR CUTTING TOOL WITH CUTTER BARS).
There are various tools for machining bevel gears. Machining with so-called face mill cutters is currently especially preferred which are equipped with a number of bar cutting blades. These bar cutting blades protrude in the axial direction of the face mill cutter and are arranged and aligned in such a way that the flanks of the tooth gaps of a bevel gear are machined. Typically, only one of the flanks of a tooth gap is cut with each bar cutting blade.
In the case of the so-called TWIN Blade™ of Klingelnberg GmbH, Germany, a bar cutting blade comprises two equivalent cutting edges which simultaneously machine the concave and convex flanks of a tooth gap.
Alternatively, cutter heads with so-called form blades are also used today. These form blades have a different shape than the bar cutters and are only reground on the breast. It is an advantage of bevel gear milling with form blades that no special grinding machine is required for regrinding the blades. The known Zyklo-Palloid method uses such form blades for example for producing spiral bevel gears.
The form blades are typically made of high-speed steel (HSS material) or hard metal (HM). The hard-metal form blades come with the disadvantage however that they are impact-sensitive. When the hard-metal form blades are used for producing large-module bevel gears, the form blades will be respectively large, heavy and especially expensive.
The invention is therefore based on the object of providing a tool for the cutting, especially the milling, of large-module bevel gears which is more cost-effective than known solutions.
It is further object of the invention to reduce the time needed for dismounting, regrinding and re-mounting the form blades.
These objects are achieved in accordance with the invention by an apparatus according to claim 1 and by a use according to claim 10.
This object is achieved according to the invention in such a way that a cutter head is used which carries several novel base holders with several cutter bars instead of the single-piece bar or form blades. In accordance with the invention, these cutter bars are arranged in the region of the clearance face, i.e. they extend to the side of the base holder.
The cutter bars are preferably made of hard metal or CBN-plated metal (cubic crystal boron nitride).
It is an advantage of the tools in accordance with the invention that they are considerably cheaper than previous tools made of hard metal. Moreover, they nevertheless offer high precision and long tool life.
It is an advantage of the tools in accordance with the invention that the cutter bars can be used several times without requiring any regrinding. The cutter bars are reversed for this purpose in order to be fastened again in the base holder.
Further advantageous embodiments are shown in the dependent claims.
Embodiments of the invention are described in the following in detail making reference to the drawings. It shows:
Terms are used in connection with the present description which are also used in relevant publications and patents. Notice shall be taken however that the use of such terms shall merely be for better understanding. The inventive idea and the scope of protection of the claims shall not be limited in their interpretation by the specific use of the terms. The invention can be applied easily to other systems of terms and/or specialist fields. Terms shall be applied analogously in other specialist fields.
The first embodiment of the invention is shown in
The cutter head 40 can be carried out identically for soft and hard machining. The form blades 10 or 20 are preferably adjusted to the respective machining form. In soft machining, hard-metal cutter bars 13.1 to 13.3 are preferably used in accordance with the invention whose cutting edges cannot be reground. The time that was required up until now for dismounting, regrinding and renewed mounting the form blades can be avoided in accordance with the invention.
CBN-plated cutter bars 13.1 to 13.3 are preferably used in hard machining in accordance with the invention. They can be reground.
Furthermore, a first receiving area 12.1 is provided for a first cutting body. Said first cutting body is a cutter bar 13.1 which is designated here as the first cutter bar.
The term cutter bar is used in the present patent application in order to describe an oblong flat cutting body. A cutter bar 13.1 in accordance with the invention typically has a length L which is larger than the width B and thickness D, as shown in
Such cutter bars 13.1, 13.2 are used in all embodiments.
A cutter bar 13.1 in accordance with the invention preferably has a rectangular or almost rectangular shape in the top view, with the respective rectangle being defined by the edges with the lengths L and B, as indicated in
Cutter bars 13.1, 13.2 and 13.3 are especially preferred which are arranged in such a way that they each have four cutting edges. A rectangular cutter bar 13.1 with four cutting edges 18.1 to 18.4 is shown in the
Cutter bars 13.1 are also suitable which are configured in such a way that they have two cutting edges each.
Such cutter bars with two or more cutting edges are used in all embodiments.
The tool 100 in accordance with the invention further comprises a second receiving area 12.2 (see
Spatially offset means that, when seen in the cutting direction S (see
The term base body 11, 21 shall be used in the present patent application in order to define a support body for the cutter bars 13.1-13.4. Preferably, the base body 11, 21 has a pyramidal or pointed shape. Such base bodies 11, 21 are used in all embodiments.
A second embodiment of the invention is shown in
Furthermore, a first receiving area 12.1 for a first cutting body is provided. Said first cutting body is a cutter bar 13.1 which is designated here as the first cutter bar. The tool 100 in accordance with the invention further comprises a second receiving area 12.2 (see
An embodiment is especially preferred in which a cavity used as chip space 16 is provided on the base body 11, 21. Details of such an especially preferred embodiment are shown in
form blade 10 with a cutter bar 13.1 is shown in
This cutter bar 13.1 is arranged in the region of the relief face 15 of the base body 11, i.e. it extends to the side of the base body 11.
The cutter bar 13.1 is made of hard metal and comprises a ground cutting edge 18.1 which extends along a longitudinal side up to a head region 4. The cutting edge 13.1 preferably comprises a ground-in protuberance for end machining a large-module bevel gear. The edge length of the cutting edge 18.1 is suitable for various module sizes, which means the cutter bar 13.1 can be used for the gearing of bevel gears of different modules.
A first embodiment of the invention in accordance with the invention is shown in
As a result of the special kind of the arrangement of the cutter bars 13.1, 13.2 and 13.3, a so-called cutting division occurs during the milling of the tooth gaps of a bevel gear. This cutting division is obtained in such a way for example that one of the cutter bars 13.1 provides a primary cutter 18.1, whereas a second cutter bar 13.2 provides a secondary cutter 18.5.
This embodiment is especially suitable for roughing-down work on large-module bevel gears.
Hard-metal cutter bars 13.1, 13.2 and 13.3 in sintered configuration are especially preferred in this embodiment because they are inexpensive.
The cutter bars 13.1, 13.2 and 13.3 are preferably designed in such a way that they each comprise four cutting edges, as described in connection with the
A further form blade 10 is shown in the
As is shown in
This form blade 10 is especially suitable for roughing and finishing work because simple adjustability is given by the possibility of height adjustment via the eccentric element 6. The eccentric element 6 can be used in all other embodiments analogously. Either one of the cutter bars 13.1, 13.2, 13.3 comprises several eccentric elements 6 or all cutter bars 13.1, 13.2, 13.3 comprise one eccentric element 6 for individual height adjustability.
A further embodiment of the invention is shown in the
This embodiment is also especially suitable for roughing and finishing work because simple adjustability of the position of the cutter bar 13.1 is given by the possibility of height adjustment via the support plate 17. A support plate 17 can be used in all other embodiments analogously.
In addition to mere support function, the support plate 17 can also have a cutting edge. If the support plate 17 comprises a cutting edge, there is also a cutting division between the cutter bar 13.1 and the support plate 17 in the embodiment as shown in the
Embodiments of the invention are especially preferred in which the cutter bar(s) 13.1, 13.2, 13.3 are clamped tangentially on the base body 11 (tangentially corresponding in this case approximately to the direction of the cutting speed; in other words, the tangential direction corresponds here to the tangent on the tool diameter or cutter head diameter). This tangential clamping is very stable because the cutter bar(s) 13.1, 13.2, 13.3 are pressed during cutting into the respective receiving area 12.1, 12.2, 12.3.
Moreover, the tangential clamping on the free surface 3 of base body 11 leads to a large contact surface of the cutter bar(s) 13.1, 13.2, 13.3 in the respective receiving area 12.1, 12.2, 12.3. Forces which occur during bevel gear milling can be better introduced and distributed into the base body 11 as a result of the large contact surface.
The cutter bar(s) 13.1, 13.2, 13.3 are preferably fastened with screws onto the base body 11.
The receiving areas for the cutter bars 13.1, 13.2, 13.3 are positioned on the base body 11 in such a way that the first cutter bar 13.1 and the second cutter bar 13.2 are arranged in a spatially offset manner and the chip space 16 is disposed in a region between the first cutter bar 13.1 and the second cutter bar 13.2.
Axes R1, R2 and R3 are indicated in
The drawings further show that the base body 11 can comprise a recess in the form of a round hole 9 for example (see
A further optional feature is shown in the
The grinding quality and the geometric precision of the cutter bar(s) 13.1, 13.2, 13.3 are very important for the achievable production quality of the bevel gear workpiece.
The cutter bar(s) 13.1, 13.2, 13.3 in accordance with the invention are made of hard metal, as already mentioned. Cutter bar(s) 13.1, 13.2, 13.3 are especially preferable which are at least partly coated.
The cutter bar(s) 13.1, 13.2, 13.3 in accordance with the invention can also be made of high-speed steel (HSS).
The present tools 10 are especially suitable for soft machining or large-module bevel gears. The tools are also suitable for use in the car industry for example although bevel gears with smaller modules are typically used there.
The tool 10 in accordance with the invention is especially suitable for machining Zyklo-Palloid spiral bevel gears.
The present tools 10 can also be designed for dry machining of bevel gears.
The cutter bar(s) 13.1, 13.2, 13.3 are preferably made of hard metal in accordance with the invention and comprise at least one ground cutting edge 18.1 which converges from the main cutting blade into the head cutting blade.
Hard-metal cutter bars 13.1, 13.2, 13.3 in sintered configuration are especially preferred for soft machining.
The base bodies 11 and 21 are preferably made of hardened case-hardening steel in accordance with the invention.
The illustrated and described cutter heads 40 are characterized in that they can be equipped flexibly with the respective form blades 10 and one and the same cutter head 40 can be used for different module ranges as a result of the various possibilities for adjusting and setting. A standard tool system is provided which can be used very flexibly.
The invention provides a new tool system which can be used for soft and hard machining of gear wheels depending on the configuration of the base body and the cutter bars. Productivity can be increased noticeably with the tools 100. Moreover, the costs in comparison with other comparative solutions could be reduced considerably.
Number | Date | Country | Kind |
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20 2007 007 063.2 | May 2007 | DE | national |
Filing Document | Filing Date | Country | Kind | 371c Date |
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PCT/EP08/54926 | 4/23/2008 | WO | 00 | 12/31/2009 |