Electric handheld machine tools

Abstract

The invention relates to an electric hand-held machine tool (1), in particular an angle grinder (2), comprising a housing (3) in which an electric motor (6) is accommodated, the electric motor driving a rotor shaft (11) being connected in a force-transmitting manner to an output unit (13) accommodated in a transmission head (12). A housing ring (16) is provided, which provides at least one guide section (27) for the transmission head (12) and a guide (30) for the electric motor (6). An air guide section (24) is formed on the side of the housing ring (16) pointing away from the housing (3), in which a ventilation device (25) fastened to the rotor shaft (11) is accommodated.

Description

Technical Field

[0001] The invention relates to an electric handheld power tool, in particular an angle grinder, having a housing in which an electric motor is accommodated, which drives a rotor shaft which is connected in a force-transmitting manner to an output unit accommodated in a gear head. Background Art

[0002] Such handheld power tools have long been known from the prior art, for example from EP 2 873 493 A2. In this case, an electric motor is usually accommodated in a housing and mounted therein, wherein the electric motor is usually designed as an EC motor and therefore comprises a stator with a plurality of windings and a rotor with a rotor shaft, wherein the rotor is mounted rotatably about an axis of rotation in the stator. A rotor lamination stack with a plurality of permanent magnets is held on the rotor shaft, so that a rotating magnetic field that drives the rotor can be generated in the stator by suitable actuation, in order to drive an embedded tool, for example a grinding wheel.

[0003] Here, the gear head is screwed onto the housing, which, however, results in the problem that the gear head is often only inaccurately oriented relative to the rotor shaft. However, this then involves the problem that the service life of the handheld power tool is adversely affected thereby. Summary of the invention

[0004] It is therefore an object of the present invention to reduce the aforementioned disadvantages and to provide an improved hand-held power tool.

[0005] This object is achieved according to the invention for a hand-held power tool of the type mentioned at the outset in that a housing ring is provided which provides at least one guide section for a transmission head and a guide for an electric motor, wherein an air guide section is formed on the side of the housing ring pointing away from the housing, in which air guide section a ventilation device fastened to the rotor shaft is accommodated.

[0006] This makes it possible to guide and orient both the electric motor and the transmission head on the housing ring and thus to center them relative to one another. By integrating the air guide section into the housing ring and by accommodating the ventilator in the air guide section, a very compact design is achieved, which makes it possible to keep the dimensions of the handheld power tool as small as possible.

[0007] It has also proven to be advantageous if the guide is arranged concentrically with the at least one guide section. It is therefore particularly advantageous if the gear mechanism head and the electric motor are oriented relative to one another. In this context, “concentrically” is also understood within the scope of the invention to mean that the center point of the guide and the center point of the at least one guide section are on a common axis, wherein it is particularly advantageous if they are on the axis of rotation.

[0008] It has also been proven within the scope of the invention that the housing ring is arranged axially in stages between the housing and the gear head. This has the advantage, in particular, of facilitating the connection of the gear head to the housing in terms of assembly technology. This means that the gear head is not in direct contact with the housing, but is spaced apart and separated from the housing by the housing ring.

[0009] It has also proven to be advantageous if an axial flange is assigned to the side of the housing ring pointing away from the housing, on which at least one guide section for the gear head is formed. This provides an additional guide for the gear head, which guide also facilitates the centering and orientation of the gear head relative to the housing ring. It has also proven to be advantageous in this respect if the number of guide sections is preferably two or more, preferably three or more, and further preferably six or less, preferably five or less, and particularly preferably four.

[0010] The production costs can be further reduced if the guide segments are designed in the shape of a circular arc and if the angle of the individual guide segments is preferably 10° or more, preferably 20° or more, particularly preferably 25° or more, further preferably 50° or less, preferably 40° or less, particularly preferably 35° or less, and very particularly preferably 30°. In this respect, it has also been found that the total angle of the guide segments is preferably 60° or more, preferably 80° or more, particularly preferably 100° or more, further preferably 250° or less, preferably 180° or less, particularly preferably 150° or less, and very particularly preferably 120°. Thus, only a small area of ​​the axial flange needs to be adapted to the shape of the gear mechanism head.

[0011] It has also proven to be particularly advantageous if the guide is formed on the side of the housing ring facing the housing. The guide makes it possible for the electric motor to be guided in the housing ring but also to be fixed and centered in the radial direction, thereby ultimately further improving the orientation of the electric motor relative to the transmission head. However, it has also proven to be advantageous in this respect if the guide comprises a contact surface for supporting the end face of the electric motor. This also facilitates the orientation of the electric motor relative to the housing ring.

[0012] It has also proven to be advantageous if the guide is designed as an annular axial web. By means of the annular axial web, a flat, radial guide in the shape of a hollow cylinder is provided for the electric motor, thus positively influencing the orientation and centering of the electric motor.

[0013] The assembly can also be facilitated by the fact that the axial web has an introduction bevel on the inner circumferential side. This in particular makes it possible to insert the electric motor into the guide in a simplified manner.

[0014] The orientation of the electric motor relative to the transmission head is further facilitated by screwing the housing ring to the electric motor via a motor screwing arrangement. It has proven in this respect that the number of screw elements of the motor screwing arrangement is preferably two or more, and more preferably four or less, and preferably three. Furthermore, the electric motor connected to the housing ring can be assembled in a simple manner.

[0015] It has also proven to be particularly advantageous to assign a motor housing to the electric motor, in which a receptacle is formed, into which a screw of the motor screwing arrangement is screwed. This ensures that there is sufficient space to form the thread pitch. However, this also has the advantage that electrical insulation relative to the stator of the electric motor is achieved by the motor housing, which ensures double insulation of the housing ring relative to the stator. However, it is also provided within the scope of the invention that the screw is screwed into other components of the electric motor, for example into the stator of the electric motor.

[0016] However, it has also been shown to be advantageous that the receptacle formed in the motor housing extends substantially over the entire length of the motor housing. This has the advantage that the receptacle can be used to accommodate screws from both sides and can therefore also be used, for example, to screw the closure cap to the motor housing.

[0017] If the housing comprises a first housing part and a second housing part, this has a positive effect on the assembly effort of the handheld power tool according to the invention, since the two housing parts can be easily connected to one another.

[0018] It has also proven to be advantageous if the housing ring connects the first housing part to the second housing part at the end face. This ensures that the two housing parts are fixed in position relative to one another, without having to tighten the two housing parts transversely to the rotor shaft in the region of the end face adjacent to the transmission head. This makes it possible to achieve particularly small grip dimensions.

[0019] It has also proven to be particularly advantageous here if the housing ring engages the first housing part and / or the second housing part at least partially on the outer circumference. As a result, the two housing parts are ultimately held from the outside, which also intensifies the fixing effect and simultaneously enables the two housing parts to be centered relative to one another. However, it is also provided within the scope of the invention that the housing ring is engaged by the two housing parts.

[0020] It has also proven to be advantageous if the housing ring is screwed to the first housing part and / or the second housing part, wherein the screwing is performed parallel to the rotor axis. As a result, the two housing parts, namely their regions on the end faces, are firmly connected to the housing ring, which has a positive effect on the mechanical loadability of the entire housing. In this regard, it has also proven to be advantageous if the number of screws of the screwing arrangement is preferably three or more, and further preferably five or less, and preferably four.

[0021] In order to further reduce the assembly effort, it has also proven to be advantageous to form at least two screw receptacles in each case in the first housing part and in the second housing part, into which the screws of the tightening structure are screwed. Here, it has also proven to be particularly advantageous to allow the tightening structure to pass through the gear head. This ultimately results in a unit consisting of the gear head, the housing ring and the two housing parts, which is fixed by the tightening structure.

[0022] It has also proven to be advantageous to form a circular segment-shaped projection on the side of the housing ring facing the housing, which projection at least partially covers the screw receptacle on the outer circumference. This achieves a further fixation of the screw of the housing part and at the same time ensures that the screw receptacle is covered, thereby achieving an improved centering of the two housing parts relative to the housing ring.

[0023] It has also been shown to be particularly advantageous that the housing is vibration-decoupled relative to the housing ring and / or the transmission head, thereby ensuring that vibrations occurring during operation of the handheld power tool are not transmitted to the housing and therefore do not have a negative impact on the user of the handheld power tool.

[0024] Yet also proved to be particularly advantageous that the housing ring is formed as a housing pot, which forms a receiving chamber that at least partially accommodates the electric motor. Here, the housing ring can therefore especially be extended axially and finally formed as a pot, in which the electric motor is at least partially accommodated. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] The invention is explained in more detail below using a number of exemplary embodiments shown in the drawings; in which:

[0026] Figure 1shows a sectional view along a longitudinal section of a first embodiment of a hand-held power tool,

[0027] Figure 2 shows a perspective exploded view of a first embodiment of a handheld power tool,

[0028] Figure 3 shows a perspective view of a first side portion of a housing ring of a handheld power tool,

[0029] Figure 4 shows a perspective view of a second side of a housing ring of a handheld power tool, and

[0030] Figure 5 A perspective view of a pot-shaped housing ring is shown. DETAILED DESCRIPTION

[0031] Figure 1 In the sectional view along the longitudinal section, an electric handheld power tool 1 is shown, which in the illustrated embodiment is designed as a wired angle grinder 2, which is usually operated at a voltage between 80 V and 280 V. Here, the handheld power tool 1 has a housing 3, which includes a first housing part 4 and a second housing part 5, which are ultimately designed as half shells. An electric motor 6 is accommodated in the housing 3, which is implemented as an EC motor and includes a stator 8 with a plurality of windings 7 and a rotor 9, which is rotatably supported around an axis of rotation 10 within the stator 8. Here, the electric motor 6 drives a rotor shaft 11 connected to the rotor 9, which is connected to an output unit 13 accommodated in a transmission head 12 in a force-transmitting manner. An embedded tool 14 is driven by the output unit 13, which is currently designed as a grinding wheel 15. Here, a housing ring 16 is arranged between the housing 3 and the gear head 12, that is, at the end faces of the first housing part 4 and the second housing part 5, which at least partially engages the first housing part 4 and the second housing part 5 on the outer circumference and thus finally clamps them. In addition to the first housing part 4 and the second housing part 5 being fixed by the housing ring 16, they are also screwed directly to each other. Here, the housing screws 17.1 are arranged perpendicular to the rotor shaft 11, more precisely in the region of the housing 3 that points away from the housing ring 16.

[0032] Especially from Figure 2As can be seen from the exploded view, the housing ring 16 is screwed to the first housing part 4 and the second housing part 5, wherein the screwing is performed parallel to the rotor shaft 11. As a result, the screw cap 18 arranged perpendicular to the rotor shaft 11 can be omitted in the area on the end side of the first housing part 4 and the second housing part 5, in which the electric motor 6 is also accommodated. A total of four threaded elements 17.2 are used for the screwing structure, which are screwed starting from the transmission head 12 and ultimately connect the transmission head 12, the housing ring 16 and the first housing part 4 and the second housing part 5 to each other. In order to accommodate the threaded elements 17.2 of the screwing structure, two threaded element receptacles 19 are respectively constructed in the first housing part 4 and in the second housing part 5, into which the threaded elements 17.2 of the screwing structure are screwed. However, in Figure 2 The exploded view shown in the figure also shows that the housing 3 is vibration-decoupled with respect to the housing ring 16 and the transmission head 12. For this purpose, a corresponding damping element 20 is provided, which is placed on the threaded element 17.2 and thus contributes to the corresponding vibration reduction and the decoupling of the housing 3. In order to improve the centering of the electric motor 6 with respect to the housing ring 16, the housing ring is screwed to the electric motor 6 by a motor screwing structure. Here, a total of three motor screws 17.3 are used, which are screwed into a receptacle 21 from the side of the housing ring 16 facing the transmission head 12, which is constructed in the motor housing 22, in which the electric motor 6 is accommodated and dust-tightly encapsulated. Here, the receptacle 21 extends substantially over the entire length of the motor housing 22 and, in addition to fastening the housing ring 16, also enables the fastening of the closure cover 23 to the motor housing 22.

[0033] On the side of the housing ring 16 pointing away from the housing 3, in the perspective view Figure 3 At the side shown in the figure, an air guide section 24 is formed, in which a fan 25 fastened to the rotor shaft 11 is accommodated. In addition, an axial flange 26 is formed on the side of the housing ring 16 facing the gear head 12, on which a total of four guide sections 27 for the gear head 12 are formed, which guide sections enable the gear head 12 to be oriented and centered relative to the housing ring 16 and the housing 3. Here, each guide section 27 is designed in the shape of a circular arc and has an angle of approximately 30° respectively, so that the total angle of the four guide sections 27 is approximately 120° in total. In addition, a total of four threaded member through-guides 28 are formed on the housing ring 16, in which the threaded member 17.2 of the screw-on structure is accommodated.

[0034] In particular, the housing ring 16 Figure 4It can be seen from the perspective view shown in that projections 29 are formed on the side of the housing ring 16 facing the housing 3 in the area of ​​the screw guide 28. These circular segment-shaped projections 29 at least partially cover the screw receptacles 19 on the outer circumference in the assembled state, which are formed in the first housing part 4 and the second housing part 5. In addition, from Figure 4 It can also be seen that a guide 30 for the electric motor 6 is formed in the housing ring 16. The guide has a contact surface 31, on which the electric motor 6 can be supported. Here, the guide 30 is designed as an annular axial web 32, which has an introduction bevel 33 on the inner circumference and thus facilitates the introduction of the electric motor 6 into the housing ring 16. By means of the guide 30 formed on the side of the housing ring 16 and by means of the guide section 27 formed on the other side of the housing ring 16, the transmission head 12 and the electric motor 6 can be oriented and centered relative to the housing ring 16 and thus relative to each other.

[0035] Figure 5 A perspective view of a second embodiment of the housing ring 16 is shown. Figures 1 to 4 The first embodiment differs substantially in that the housing ring 16 is designed as a housing cup 34 which is at least partially closed at the end face and forms a receiving chamber 35 in which the electric motor 6 can be at least partially received.

[0036] List of reference numerals:

[0037] 1 Handheld machine tools

[0038] 2 Angle grinder

[0039] 3 Housing

[0040] 4 First housing part

[0041] 5 Second housing part

[0042] 6 Electric Motor

[0043] 7 Winding

[0044] 8 Stator

[0045] 9 Rotor

[0046] 10 Axis of rotation

[0047] 11 Rotor shaft

[0048] 12 Transmission mechanism head

[0049] 13 Output Unit

[0050] 14 Embedded Tools

[0051] 15 Grinding wheel

[0052] 16 Shell ring

[0053] 17.1 Housing threads

[0054] 17.2 Threaded parts

[0055] 17.3 Motor threaded parts

[0056] 18 Screw top cap

[0057] 19 Screw member receiving portion

[0058] 20 Damping element

[0059] 21 Accommodation

[0060] 22 Motor housing

[0061] 23 Closure cover

[0062] 24 Air guide section

[0063] 25 Ventilation equipment

[0064] 26 Axial flange

[0065] 27 Guide section

[0066] 28 The threaded member passes through the guide portion

[0067] 29 protrusion

[0068] 30 Guide

[0069] 31 Abutment surface

[0070] 32 Axial tab

[0071] 33 Introduction of inclined section

[0072] 34 Shell tank

[0073] 35 Accommodation room.

Claims

1. An electric hand-held power tool (1) having a housing (3) in which an electric motor (6) is accommodated, which drives a rotor shaft (11) which is connected in a force-transmitting manner to an output unit (13) accommodated in a transmission head (12), characterized in that: A housing ring (16) is provided which provides at least one guide section (27) for the transmission head (12) and a guide (30) for the electric motor (6), and an air guide section (24) is formed on the side of the housing ring (16) pointing away from the housing (3), in which a ventilation device (25) fastened to the rotor shaft (11) is accommodated, wherein an axial flange (26) is assigned to the side of the housing ring (16) pointing away from the housing (3), on which at least one guide section (27) for the transmission head (12) is formed.

2. The hand-held power tool (1) according to claim 1, characterized in that The hand-held power tool (1) is an angle grinder (2).

3. The handheld power tool (1) according to claim 1, characterized in that The guide portion (30) is arranged concentrically with the at least one guide section (27).

4. The hand-held power tool (1) according to any one of claims 1 to 3, characterized in that The housing ring (16) is arranged in a stepped manner in the axial direction between the housing (3) and the transmission head (12).

5. The hand-held power tool (1) according to any one of claims 1 to 3, characterized in that The number of the guide sections (27) is two or more and six or less.

6. The hand-held power tool (1) according to claim 5, characterized in that The number of the guide sections (27) is three or more and five or less.

7. The hand-held power tool (1) according to claim 6, characterized in that The number of the guide sections (27) is four.

8. The hand-held power tool (1) according to any one of claims 1 to 3, characterized in that The guide sections (27) are designed in the shape of a circular arc, and the angle of each guide section (27) is 10° or more and 50° or less.

9. The hand-held power tool (1) according to claim 8, characterized in that The angle of each guide section (27) is 20° or more and 40° or less.

10. The hand-held power tool (1) according to claim 9, characterized in that The angle of each guide section (27) is 25° or more and 35° or less.

11. The hand-held power tool (1) according to claim 10, characterized in that The angle of each guide section (27) is 30°.

12. The hand-held power tool (1) according to claim 8, characterized in that The total angle of the guide section (27) is 60° or more and 250° or less.

13. The hand-held power tool (1) according to claim 12, characterized in that The total angle of the guide section (27) is 80° or more and 180° or less.

14. The hand-held power tool (1) according to claim 13, characterized in that The total angle of the guide section (27) is 100° or more and 150° or less.

15. The hand-held power tool (1) according to claim 14, characterized in that The total angle of the guide section (27) is 120°.

16. The hand-held power tool (1) according to any one of claims 1 to 3, characterized in that The guide (30) is formed on the side of the housing ring (16) facing the housing (3).

17. The hand-held power tool (1) according to any one of claims 1 to 3, characterized in that The guide portion (30) comprises a contact surface (31) which is used to support the end side of the electric motor (6).

18. The hand-held power tool (1) according to any one of claims 1 to 3, characterized in that The guide (30) is designed as an annular axial web (32).

19. The hand-held power tool (1) according to claim 18, characterized in that The axial web (32) has an introduction bevel (33) on the inner circumferential side.

20. The hand-held power tool (1) according to any one of claims 1 to 3, characterized in that The housing ring (16) and the electric motor (6) are tightened by a motor tightening structure.

21. The hand-held power tool (1) according to claim 20, characterized in that The number of the motor screw members (17.3) of the motor tightening structure is two or more, and four or less.

22. The hand-held power tool (1) according to claim 21, characterized in that The number of the motor screw parts (17.3) of the motor tightening structure is three.

23. The hand-held power tool (1) according to claim 20, characterized in that The electric motor (6) is assigned a motor housing (22), in which a receptacle (21) is formed, into which a motor screw (17.3) of the motor screw connection is screwed.

24. The hand-held power tool (1) according to claim 23, characterized in that A receptacle (21) formed in the motor housing (22) extends over the entire length of the motor housing (22).

25. The hand-held power tool (1) according to any one of claims 1 to 3, characterized in that The housing (3) comprises a first housing component (4) and a second housing component (5).

26. The hand-held power tool (1) according to claim 25, characterized in that The housing ring connects the first housing part (4) to the second housing part (5) at the end side.

27. The hand-held power tool (1) according to claim 25, characterized in that The housing ring (16) engages the first housing part (4) and / or the second housing part (5) at least partially on the outer circumferential side.

28. The hand-held power tool (1) according to any one of claims 1 to 3, characterized in that The housing ring (16) is screwed to the housing (3), wherein the screwing is performed parallel to the rotor shaft (11).

29. The hand-held power tool (1) according to claim 28, characterized in that The number of the screw members (17.2) of the fastening structure between the housing ring (16) and the housing (3) is three or more, and five or less.

30. The hand-held power tool (1) according to claim 29, characterized in that The number of the screw parts (17.2) of the fastening structure between the housing ring (16) and the housing (3) is four.

31. The hand-held power tool (1) according to claim 28, characterized in that The housing (3) comprises a first housing part (4) and a second housing part (5), wherein at least two screw-on receptacles (19) are respectively formed in the first housing part (4) and in the second housing part (5), into which screw-on receptacles the screws (17.2) of the screwing structure of the housing ring (16) and the housing (3) are screwed.

32. The hand-held power tool (1) according to claim 31, characterized in that A circular segment-shaped projection (29) is formed on the side of the housing ring (16) facing the housing (3), which projection at least partially covers the screw receptacle (19) on the outer circumference.

33. The hand-held power tool (1) according to any one of claims 1 to 3, characterized in that The housing (3) is vibration-decoupled from the housing ring (16) and / or the gear head (12).

34. The hand-held power tool (1) according to any one of claims 1 to 3, characterized in that The housing ring (16) is designed as a housing cup (34), which forms a receiving chamber (35) for at least partially receiving the electric motor (6).

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