BRUSHLESS ELECTRIC MOTOR

Abstract

Brushless electric motor for an electric handheld power tool, wherein the electric motor has an end plate and a Hall board which is arranged on the end plate, wherein the Hall board is axially fixed to the end plate by an elastic O-ring.

Claims

1-12. (canceled)

13. A brushless electric motor for an electric handheld power tool, the electric motor comprising: an end plate; and a Hall board arranged on the end plate, the Hall board being axially fixed to the end plate by an elastic O-ring.

14. The electric motor as recited in claim 13 wherein the Hall board is axially fixed to the end plate exclusively by the O-ring.

15. The electric motor as recited in claim 13 wherein the end plate has a central bearing for receiving a rotor axis.

16. The electric motor as recited in claim 15 wherein the central bearing is fastened to the end plate by at least one radial retaining web.

17. The electric motor as recited in claim 16 wherein the Hall board is supported against the at least one radial retaining web in the axial direction.

18. The electric motor as recited in claim 15 further comprising at least one supporting collar formed on the central bearing, the O-ring being supported against the supporting collar.

19. The electric motor as recited in claim 18 wherein the supporting collar has a contact area for the O-ring, the contact area oriented obliquely in relation to the rotor axis.

20. The electric motor as recited in claim 19 wherein an angle between the rotor axis and a surface normal of the contact area is less than 90 degrees.

21. The electric motor as recited in claim 20 wherein the angle is between 40 and 60 degrees.

22. The electric motor as recited in claim 13 wherein the Hall board includes a disk with a concentric hollow-cylindrical recess.

23. The electric motor as recited in claim 22 wherein the end plate has a central bearing for receiving a rotor axis and an inside diameter of the recess is greater than an outside diameter of the central bearing.

24. The electric motor as recited in claim 23 further comprising at least one supporting collar formed on the central bearing, the O-ring being supported against the supporting collar, and the inside diameter of the recess being greater than a supporting collar outside diameter.

25. The electric motor as recited in claim 13 wherein the Hall board and the O-ring are located on a side of the end plate facing away from the rotor.

26. An electric handheld power tool comprising the electric motor as recited in claim 13.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In the figures, identical and similar components are denoted by the same reference signs. In the figures:

[0013] FIG. 1 shows a first preferred exemplary embodiment of a brushless electric motor according to the invention looking at the side that is averted from the rotor;

[0014] FIG. 2 shows a section through the end plate of the electric motor of FIG. 1; and

[0015] FIG. 3 shows a rotor-side view of the end plate of the electric motor of FIG. 1.

DETAILED DESCRIPTION

[0016] A preferred exemplary embodiment of a brushless electric motor 10 according to the invention looking at the side RS that faces away from the rotor is depicted in FIG. 1. The electric motor 10 has an end plate 1 and a Hall board 3 which is arranged on the end plate 1. In the exemplary embodiment depicted in the present case, the end plate 10 is a B end plate, that is to say the end plate which is situated opposite the drive side of the electric motor 10. For reasons of clarity, the electric motor 10 is not shown in its entirety, that is to say, in particular, a stator winding or a stator core (apart from a few stator segments which are connected to the end plate 1) is not depicted in FIG. 1.

[0017] According to the invention, the Hall board 3 is axially fixed, that is to say fixed in the axial direction AR, to the end plate 1 by means of an elastic O-ring 5. In the present case, the Hall board 3 is axially fixed to the end plate 1 exclusively by means of the O-ring 5. The Hall board 3 and the O-ring 5 are both located on the side RS of the end plate 1 that faces away from the rotor and is shown in FIG. 1.

[0018] FIG. 1 clearly shows that the end plate 1 has a central bearing 2 for receiving a rotor axis 6. A rotor 11 of the electric motor 10 itself is shown in FIG. 1 solely schematically. Three supporting collars 8, against which the O-ring 5 is supported in the axial direction AR, are formed on the central bearing 2.

[0019] An electric handheld power tool 100 which is equipped with an electric motor 10 according to the invention is schematically depicted at the bottom right of FIG. 1.

[0020] FIG. 2 shows a section through the end plate 1 of the electric motor 10 of FIG. 1. Said figure clearly shows that the central bearing 2 is fastened to the end plate 1 by means of a radial retaining web 7 (cf. FIG. 3). In this case, the Hall board 3 is firstly supported against the radial retaining web 7 in the axial direction AR. Secondly, the elastic O-ring 5 is supported against the supporting collar 8, which is formed on the central bearing 2, in the axial direction AR. Therefore, the Hall board 3, which has one Hall sensor 4 here by way of example, is axially fixed to the end plate 1 by means of the elastic O-ring 5.

[0021] The supporting collar 8 has a contact area 8′ for the O-ring 5, which contact area is oriented obliquely in relation to the rotor axis 6. In this case, an angle W which is enclosed between the rotor axis 6 and the surface normal N of the contact area 8′ is less than 90 degrees. In the exemplary embodiment illustrated in the present case, the angle W is approximately 45, this constituting a good compromise between clamping action and ease of assembly.

[0022] As can be gathered from FIG. 2, the Hall board 3 is designed, in the form of a disk, with a concentric hollow-cylindrical recess 9. In this case, an inside diameter ID of the recess 9 is greater than an outside diameter AD of the central bearing 2 including the supporting collar 8. Therefore, the Hall board 3 can be pushed onto the central bearing 2 in the axial direction AR and can then be secured in an interlocking manner in the axial direction AR by the O-ring 5. In this case, the exact positioning of the Hall board 5 in the axial direction AR is ensured by the clamping action of the elastic O-ring 5.

[0023] FIG. 3 now shows a rotor-side view RB of the end plate of the electric motor of FIG. 1. Said figure clearly shows the central bearing 2 and the rotor axis 6 which is arranged coaxially in relation to said central bearing. In the exemplary embodiment depicted in the present case, the central bearing 2 is fastened to the end plate 1 by means of six retaining webs 7 which each extend in the radial direction RR.

[0024] As can be gathered from FIG. 3, the disk-like Hall board 3 is exactly positioned in the radial direction RR by the O-ring 5 which can be identified through the Hall board 3 in sections. This, in the sense of functional integration, at the same time as the exact positioning of the Hall board 5 in the axial direction AR by the clamping action of the elastic O-ring 5 mentioned in relation to FIG. 2.

LIST OF REFERENCE SIGNS

[0025] 1 End plate [0026] 2 Central bearing [0027] 3 Hall board [0028] 4 Hall sensor [0029] 5 O-ring [0030] 6 Rotor axis [0031] 7 Radial retaining web [0032] 8 Supporting collar [0033] 8′ Contact area [0034] 9 Recess [0035] 10 Brushless electric motor [0036] 100 Electric handheld power tool [0037] AD Outside diameter [0038] AR Axial direction [0039] ID Inside diameter [0040] N Surface normal [0041] RB Side that faces the rotor [0042] RR Radial direction [0043] RS Side that is averted from the rotor [0044] W Angle