EP2821179A1 - Angle grinder - Google Patents

Abstract

The present invention relates to a first angle grinder (10) with a motor (12) for driving a tool spindle (18), wherein the tool spindle (18) via an angular gear assembly (14) at an angle to a driving shaft (12c) of the motor ( 12) is arranged, and wherein the angular gear assembly (14) is received in an associated gear housing (16) from which a free end of the tool spindle (18) can extend, on which a disk-shaped to the tool spindle (18) rotatable Tool (22) by means of a tool flange (20) can be fastened. The invention is characterized in that at least the front gear housing (16) of the angular gear assembly (18) facing away from the free end of the tool spindle end surface (16a), wherein the maximum distance between this and an end face (18a) of the free end of the tool spindle (18) defines a height (H) of the gear housing (16) and wherein the height (H) has a predetermined ratio to the diameter of the disc-shaped tool (22) of at most 1 to 2, preferably from 2 to 5.

Description

The invention relates to an angle grinder according to the preamble of claim 1. The term angle grinder is to be understood in the present case also typical cut-off devices.

Angle grinders of this type have become known several times in the art. In this case, different ways of forming the angular gear arrangement have been proposed, including the use of belt drives (for example, according to DE 43 42 986 C1 or DE 159 975 A1 ). Angular gear arrangements are also known with a pinion on the motor shaft and a bevel gear or ring gear, which is fastened on the tool spindle (eg. DE 140 65 658 A1 or US 6,386,961 B1 ). Finally, in the prior art (see, for example EP 0 579 949 A1 ) also proposed flexible drive shafts.

The German patent applications of the Applicant DE 10 2008 059 247 A1 and DE 10 2009 053 614 A1 also deal with the specific design of an angle grinder, which in particular has a compact and flat construction of the gear housing to allow a simplified accessibility of the angle grinder even in tight processing spaces such as in acute corners or the like.

For this the beats DE 10 2008 059 247 A1 a hat-shaped design of the Tellerradwinkelgetriebeanordnung before, wherein the recess of the ring gear is oriented facing the tool or the free end of the tool spindle.

The DE 10 2008 059 247 A1 suggests, however, that the tool spindle is formed in one piece and at least one bearing seat portion for a rolling bearing, designed as a crown portion of the angular gear assembly, a Supporting section for the grinding tool or for a support flange for the grinding tool and a threaded portion for a clamping means for fixing the grinding tool to the tool spindle. Due to the one-piece design a particularly compact design should be achieved.

The present invention is therefore based on the object to provide an alternative solution for an angle grinder of the type described above, which also has a compact and flat construction at least in the region of the gear housing of the angle gear assembly.

This object is achieved by an angle grinder, which has the features of claim 1.

Accordingly, an angle grinder with a motor for driving a tool spindle is proposed, wherein the tool spindle is arranged via an angular gear arrangement at an angle to a driving shaft of the motor, and wherein the angular gear assembly is accommodated in an associated gear housing, out of which a free end of Tool spindle is able to extend, on which a disc-shaped, rotatable about the central longitudinal axis of the tool spindle tool by means of a werkzugflansches is fastened. According to the invention, the gear housing is designed such that at least the front gear housing of the angular gear assembly has a facing away from the free end of the tool spindle end surface, wherein the maximum distance between this and an end face of the free end of the tool lock defines a height of the gear housing and wherein the height has predetermined ratio to the diameter of the disk-shaped tool of a maximum of 1 to 2, in particular from 2 to 5.

The free end of the tool spindle is thus defined as the area which protrudes from the gear housing and on which the tool can be attached.

The tool flange forms a support section for the disk-shaped tool, which can be at least partially brought into contact with these to take a defined position relative to the tool spindle. Using a clamping device, such as a clamping nut, the tool can be clamped against the tool flange for attachment to the tool spindle. The tool flange may be formed as a separate element which can be fastened to the tool spindle, or be formed integrally with the tool spindle.

Usually, when using an angle grinder, such as the angle grinder according to the invention, that portion of the disk-shaped tool used for processing, extending from the tool spindle in the forward direction, d. H. extends away from the engine. Accordingly, the gear housing dimensions in just this front area are particularly relevant for the accessibility of the angle grinder in a narrow processing space. Hereinafter, the front portion of the transmission case is understood to mean that portion which extends axially from the tool spindle to the front, i.e., the longitudinal axis of the driving shaft of the motor. extending from the engine end remote from the transmission housing.

By definition, therefore, facing away from the free end of the tool spindle end face forms the highest in this area, ie axially remote from an end face of the free end of the tool spindle portion of the front gear housing and consequently limited together with the end face the relevant height of the front gear housing.

The end surface facing away from the free end of the tool spindle is formed by an outer surface of the gear housing in the region of the tool spindle. The end surface of the housing and the end face of the tool spindle may be formed parallel to each other or inclined to each other. In this case, at least the maximum distance between them defines the height of the angle grinder in the area of the tool spindle, which has a predetermined ratio of at least 2 to 5 with respect to the diameter of the disk-shaped tool. This ratio of the height to the diameter of the tool designed, for example, as a grinding wheel can in turn ensure improved accessibility of the angle grinder into narrow or pointed corners.

Furthermore, it can be provided that the tool-facing end surface of the tool flange spans an imaginary plane which at least partially intersects the motor.

The end face of the tool flange facing the free end of the tool spindle denotes the side of the tool flange which is closest to the free end of the tool spindle, which projects out of the housing. As described above, this generally coincides with the gear housing facing top of an adjacent disc-shaped tool and defines an imaginary plane, which is offset relative to the motor housing and the motor in such a way that it at least partially intersects the motor.

The gear housing thus has at least in the region of the tool flange a smaller (relative to the tool spindle axis) axial extent than the motor housing and the motor therein.

Furthermore, it can be provided that a tangent, which can be applied starting from a peripheral edge of the disk-shaped tool to the gear housing, together with the imaginary plane forms an angle of at most 40 °, in particular of at most 35 °, preferably less than 34 °. It is thus defined a tangent which is applied starting from a peripheral edge of a disk-shaped tool to the transmission housing. The inclination of the tangent thus depends on two factors, namely on the one hand the diameter of the grinding tool used and on the other by the specific design of the gear housing, in particular of possibly mounted on the housing bevels, which have a favorable slope for the tangent. This likewise imaginary tangent encloses an angle of maximally 40 ° with the imaginary plane defined above. The smaller the angle, the more of course the accessibility of the angle grinder and thus its handling will be improved.

It is basically possible, in order to obtain a uniform indication of the angle described above, to project the peripheral edge of the disk-shaped tool into the imaginary plane. In this way, the tangent - regardless of the specific design of the tool as a cranked or a flat disc - always the same tendency for discs with the same diameter. Alternatively, however, it is also possible to start from the actual peripheral edge, since in practice this determines the actual accessibility of the angle grinder. In this case also determines the concrete design of the tool as a cranked or flat disc, the inclination of the imaginary tangent.

It can also be advantageously provided that the radius of the disk-shaped tool is smaller than the radial extent of the gear housing from the central longitudinal axis of the tool spindle. The radial extent of the transmission housing accordingly extends in the direction parallel to the tool level. The gear housing according to the invention has a comparatively small extent in the axial direction (relative to the central longitudinal axis of the tool spindle) starting from the central longitudinal axis of the tool spindle, but in the radial direction a greater extent than the radius of the disk-shaped tool. In combination with the offset of the transmission housing according to the invention, whose imaginary plane is able to cut the motor at least partially, a transmission housing axially shorter than the motor housing can be provided, which in turn improves the accessibility of the angle grinder. By this radially comparatively elongated design of the gear housing, the grinding wheel can be mounted independently of the dimensions of the motor housing close to the free end of the tool spindle facing end surface of the gear housing, ie the standing out of the gear housing part of the tool spindle are kept relatively short.

Furthermore, it can be provided that the angular gear arrangement comprises a ring gear, wherein the ring gear is formed substantially hat-shaped with a peripheral flange and a receiving portion forming the hat shape, wherein on the flange a toothing of the ring gear is provided, and wherein the receiving portion is suitable, at least to receive a part of a bearing the tool spindle relative to the gear housing bearing device.

The receiving portion of the ring gear is thus opened in one direction, wherein the opening of the exception portion is limited in the other direction by an elevation formed to the other side of the ring gear. This survey may be formed dome-shaped and viewed from the outside, for example, cylindrical or conical basic shape.

The bearing device may in particular comprise two rolling bearings, which serve for the rotatable mounting of the tool spindle within the gear housing. In a particular embodiment, the receiving section is capable of accommodating not only one but possibly also a plurality of bearings of the bearing device. In this way, even more space can be saved in the axial direction compared to the prior art.

The toothing of the ring gear is used for engagement with a pinion gear, which is driven by the motor shaft. Thus, the torque is transmitted from the motor shaft to the tool spindle via the teeth of the ring gear. Usually, the ring gear can be rotatably connected to the tool spindle, wherein the tool spindle is rotatably supported, for example via two bearings as a bearing device within the gear housing.

According to one embodiment of the invention, the toothing of the ring gear can be arranged on a free end of the tool spindle facing side of the ring gear. In such an arrangement, the toothing of the ring gear is preferably the opening of the receiving portion of the ring gear from the free end of the tool spindle pioneered oriented to provide a particularly space-saving design of the ring gear in the axial direction.

Alternatively, the toothing of the ring gear can also be arranged on a side facing away from the free end of the tool spindle side of the ring gear. In this design variant, if appropriate, the opening of the receiving portion of the ring gear is oriented towards the free end of the tool spindle.

As a further conceivable alternative, however, it is also possible that the angular gear arrangement comprises a ring gear, which is formed substantially disc-shaped, wherein on the outer edge of the ring gear toothing is provided, which is arranged on one side of the ring gear, wherein at least a part of a the tool spindle relative to the gear housing superimposed storage device, preferably all parts of the bearing device is arranged with respect to the ring gear on the same side or are, like the teeth.

Further advantages and features of the present invention will become apparent from the claims and the following description of the figures and the accompanying figures.

The present invention will now be described in more detail with reference to the accompanying drawings, which illustrate by way of example preferred embodiments of the invention, in which the individual features of the invention are combined. Of course, the person skilled in the art will also be able to consider them detached from one another and / or to combine them into meaningful combinations.

Figur 1

Ein erfindungsgemäßes Winkelschleifgerät in längsgeschnittener Darstellung;

Figuren 2 a bis 2c

Unterschiedliche Varianten der Ausbildung eines Tellerrads des erfindungsgemäßen Winkelschleifgeräts in längsgeschnittener schematischer Darstellung.

Show it:

FIG. 1

An inventive angle grinder in longitudinal section;

FIGS. 2 a to 2 c

Different variants of the formation of a crown wheel of the angle grinder according to the invention in a longitudinally sectioned schematic representation.

The FIG. 1 shows a machine tool according to the invention in the form of an angle grinder 10 according to a first embodiment. This differs from the embodiments of the FIGS. 2 a to 2 c exclusively in the specific embodiment of an angle gear assembly 14 of the angle grinder 10. The in the FIGS. 2a to 2c For the same features, therefore, the variants shown have the same reference numerals, but depending on the embodiment, the numbers "1", "2" and "3" are prefixed.

That in the FIG. 1 cut along a central longitudinal axis L ₁ angle grinder includes a motor 12 having a stator 12 which surrounds a rotor 12b, which rotates with a driving shaft 12c of the motor 12 about its longitudinal axis _L1. Furthermore, an angular gear assembly 14 is provided to transmit a transmission of the torque from the driving shaft 12 of the motor 12 to a tool spindle 18 arranged at an angle thereto. The angular gear assembly 14 is received in a gear housing 16 and includes in addition to the tool spindle 18 a tool flange 20, which serves together with a clamping nut 34 for attachment of a disk-shaped tool 22 on the tool spindle 18, a bearing means 28 for supporting the tool spindle 18 within the gear housing 16 as well a ring gear 24 provided for decreasing the input torque from the driving shaft 12c. The tool spindle 18 can rotate together with a tool 22 attached thereto about its central longitudinal axis L ₂ .

As based on the FIG. 1 can be clearly seen, the tool flange is opposite to in FIG. 1 shown lower edge of the motor stator 12a after (in FIG. 1 ) arranged above offset so that its end face facing the tool 20a an imaginary plane E spans, which intersects the motor 12 in the region of its stator 12a.

Based on this specific embodiment of the angular gear arrangement 14, a particularly flat and space-saving design of the angle grinder 10 is provided in the region of its disk-shaped tool 22, which makes it possible to use the angle grinder also in areas where the available processing space is comparatively small (eg at acute-angled corners). How to use the FIG. 1 can also recognize, the gear housing 16 includes in the area of the tool spindle 18 one of the free end of the tool spindle 18th opposite end surface 16a and parallel thereto arranged a housing cover 16b.

Usually, when using an angle grinder, such as the angle grinder 10 of the invention FIG. 1 , the area of the disc-shaped tool 22 used, which extends from the tool spindle 18 in the forward direction, ie, away from the motor 12. Accordingly, the gear housing dimensions in just this front area are particularly relevant for the accessibility of the angle grinder in a narrow processing space. Hereinafter, as the front region of the transmission housing, that region is understood which extends axially relative to the longitudinal axis L ₁ from the tool spindle to the front end (of the motor 12) of the transmission housing.

By definition, therefore, facing away from the free end of the tool spindle end surface 16a forms the highest in this area, d. H. axially distal from an end face 18 a of the free end of the tool spindle 18 portion of the front gear housing 16 and thus limited together with the end face 18 a height H of the front gear housing sixteenth

An addition to this height H further relevant size for the accessibility of the angle grinder in, for example, corner corners or the like represents the inclination of a tangent T, which is indicated by the angle α. In this case, the tangent T extends from a peripheral edge of the tool 22 along the gear housing 16 and clamped together with the imaginary plane E the angle α. The smaller the height H and the flatter the inclination of the tangent T, the better the accessibility of the angle grinder 10 in limited processing spaces.

Like in the FIG. 1 In principle, in order to obtain a uniform indication of the angle α described above, it is possible to project the peripheral edge of the disk-shaped tool 22 into the imaginary plane E (projection point P). In this way, the tangent T - regardless of the specific design of the tool 22 as a cranked disc, as in the FIG. 1 , or as a flat disc - always the same inclination for discs of the same diameter.

Alternatively, however, it can also be assumed that the actual peripheral edge of the disc 22, since this determines the actual accessibility of the angle grinder 10 in practice. In this case, in addition to the diameter D and the height H, the concrete design of the tool 22 as a cranked or as a flat disc before, how well you get with the angle grinder 10 in hard-to-reach processing spaces.

The further dimensions of the gear housing 16 from the area of the tool spindle 18 toward the motor 12 therefore only play a role for accessibility insofar as they are not allowed to have any projections extending beyond the tangent T or an abutment of the disk-shaped tool 22 to the Tool flange 20 must be possible without obstruction.

Accordingly, as in FIG. 1 can be seen, the radial extent of the gear housing 16 of the tool spindle 18 and of its central longitudinal axis L ₂ in the direction of the motor 12 along the longitudinal axis L _{1 of} the driving shaft 12c of the motor 12 sized larger than the radius D / 2 of the disc-shaped tool 22. In this way, a disincentive installation of the tool 22 to the tool flange 20 readily possible and it is a particularly flat structure of the gear housing 16 regardless of the design of the motor housing (not shown) is provided.

Another special feature of the present invention can be seen in the embodiment of the angular gear arrangement 14, in particular of the ring gear 24. According to the invention, different designs for the ring gear are proposed, which allow the most space-saving design of the angular gear arrangement.

At the in FIG. 1 As shown in the embodiment shown, the ring gear 24 as well as in FIG. 2a shown variant disc-shaped, wherein at the outer edge 28, 126 of the ring gear 24, 124 a toothing 126 a (see. FIG. 2a The teeth serve in a known manner to the driving torque of the driving shaft 12 c of the motor 12 from a drive pinion 30 to the ring gear 24 and thus to transmit the tool spindle 18. The ring gear 24 may, as shown, be formed as a separate element which is rotatably connected to the tool spindle 18, or alternatively be formed integrally with the tool spindle.

The inventive arrangement of the toothing on the same side of the ring gear as the bearing of the bearing device, the space required for the bearing device in the axial direction (relative to the central longitudinal axis L _{2 of} the tool spindle 18) at the same time for the arrangement of the teeth 126a of the ring gear and for used the engagement of the toothing in the Antriebsritzes 30.

In an alternative embodiment of the ring gear according to the FIGS. 2b and 2c the ring gear is not disk-shaped, but has a hat-shaped design and, in addition to an outer flange 226, 326, on which the teeth 226a and 326a are formed, has a receiving portion 232, 323 forming the hat shape.

The receiving portion 232, 332 of the hat-shaped ring gear 224, 324 is bounded by a protrusion 232 a, 332 a, which is formed dome-shaped and from the outside regarded as an example may have a cylindrical or conical basic shape, but this is not mandatory. The receiving section serves to at least part of the bearing device 228, 328, ie, for example, as in FIG. 2b shown one of the rolling bearings 228a of the bearing device 228 or as in Figure 2c shown to accommodate even both bearings of the bearing device 328. The teeth 226a and 326a are respectively formed on a side of the ring gear 224, 324 facing away from the opening of the receiving portion 232, 323. By providing the teeth 226a, 326a on the side of the ring gear on which extends to the elevation 232a, 323a, in turn, the space required for this anyway (relative to the longitudinal axis L _{2 of} the tool spindle 18) space required for the pinion shaft 230, 330 used, which reduces the axial height.

The bearings of the bearing device 28 can be secured in position within the housing 16, usually by projections or shoulders on the gear housing 16 and by providing a snap ring or the like, regardless of the design of the ring gear.

Claims (9)

An angle grinder (10) having a motor (12) for driving a tool spindle (18), the tool spindle (18) being disposed through an angular gear assembly (14) at an angle to a driving shaft (12c) of the motor (12), and wherein the angular gear arrangement (14) is accommodated in an associated gear housing (16) from which a free end of the tool spindle (18) can extend, on which a disc-shaped tool rotatable around the central longitudinal axis (L ₂ ) of the tool spindle (18) (22) can be fastened by means of a tool flange (20),
characterized in that at least the front gear housing (16) of the angular gear assembly (18) facing away from the free end of the tool spindle end surface (16a), wherein the maximum distance between this and an end face (18a) of the free end of the tool spindle (18) a height (H) of the gear housing (16) defined and wherein the height (H) has a predetermined ratio to the diameter of the disc-shaped tool (22) of at most 1 to 2, preferably from 2 to 5. Angle grinder (10) according to claim 1,
characterized in that the tool (22) facing the end surface (20a) of the tool flange (20) spans an imaginary plane (E), which at least partially intersects the motor (12). Angle grinder (10) according to one of claims 1 or 2,
characterized in that a tangent (T), which starting from a peripheral edge of the disc-shaped tool (22) to the transmission housing (16) can be applied, together with the imaginary plane (E) an angle (α) of a maximum of 40 °, in particular of at most 35 °, preferably less than 34 °. Angle grinder (10) according to one of the preceding claims,
characterized in that the radius (D / 2) of the disc-shaped tool (22) is smaller than the radial extent of the gear housing (16) from the central longitudinal axis (L ₂ ) of the tool spindle (18). Angle grinder according to one of the preceding claims,
characterized in that the angular gear assembly comprises a ring gear (224; 324), wherein the ring gear is formed substantially hat-shaped with a circumferential flange (226; 326) and a receiving portion forming the hat shape (232; 332), wherein on the flange a toothing (226a, 326a) of the ring gear, and wherein the receiving portion (232; 332) is adapted to receive at least a portion of a bearing means (228; 328) supporting the tool spindle (218; 318) opposite the gear housing. Angle grinder according to claim 5,
characterized in that the toothing (226a, 326a) of the ring gear is arranged on a side of the ring gear facing the free end of the tool spindle. Angle grinder according to claim 5 or 6,
characterized in that the opening of the receiving portion (232; 332) of the ring gear is oriented in a pioneering manner from the free end of the tool spindle. Angle grinder according to claim 5,
characterized in that the toothing of the ring gear on one of the free end of the tool spindle facing away from the ring gear is arranged. An angle grinder (10) according to any one of claims 1 to 4,
characterized in that the angular gear arrangement (14) has a ring gear (26, 126), wherein the ring gear is formed substantially disc-shaped, wherein on the outer edge (26, 126) of the ring gear, a toothing (126a) is provided which on a At least a portion of the tool spindle (18, 118) relative to the gear housing (16) overlapping bearing means (28, 128), preferably all parts of the bearing means (28; 128) is arranged on the same side of the ring gear.

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