Stator segment with diagonal surfaces

Abstract

The invention relates to a stator for an electric motor, in particular as a drive for a machine tool, containing at least one first and second tooth device, each of which comprises a radially arranged web element for receiving a coil winding. Each tooth device contains an arched ring section and a connecting device with a first and second connecting element, wherein the first and second connecting element are designed to be wedge-shaped in a corresponding manner such that in a connected state, a first contact surface, which runs diagonally to a tooth segment plane, of the first connecting element rests against a second contact surface, which runs diagonally to the tooth segment plane, of the second connecting element.

Description

[0001] Stator segment with inclined surfaces

[0002] The present invention relates to a stator for an electric motor, in particular as a drive for a machine tool, comprising at least a first and a second tooth device, each with a radially arranged web element for receiving a coil winding.

[0003] Stators as a component for electric motors according to the state of the art essentially comprise a ring element and a number of toothed elements. The toothed elements extend from an inner surface of the ring element to a center point of the ring element. A circular free space remains at the free end of the toothed elements for a rotor. Each toothed element serves to accommodate and hold a wound coil on conductive coil wire to generate a magnetic field.

[0004] Especially for small stators, winding the individual tooth elements with a coil wire usually involves a significant technical effort. The available space between adjacent tooth elements is often tight, so quickly and, above all, neatly winding a coil around a tooth element requires a lot of time, requires a complex winding device, and is expensive.

[0005] It is therefore an object of the present invention to solve the problem described above.

[0006] The problem is solved by the subject matter of independent patent claim 1.

[0007] Advantageous embodiments of the subject matter of the invention are contained in the dependent claims.

[0008] The object is achieved in particular by a stator for an electric motor, in particular as a drive for a machine tool, comprising at least a first and a second tooth device, each with a radially arranged web element for receiving a coil winding.

[0009] According to the invention, each tooth device comprises an arcuate ring section and a connecting device with a first and second connecting element, wherein the first and second connecting elements are correspondingly wedge-shaped, so that in a connected state, a first contact surface of the first connecting element, which extends obliquely to a tooth segment plane, bears against a second contact surface of the second connecting element, which extends obliquely to the tooth segment plane.

[0010] The fit can also be understood as the degree of fit or accuracy of fit.

[0011] According to a further advantageous embodiment, it may be possible for the first and second connecting elements to be designed such that a connecting surface has both a section running obliquely to the tooth segment plane and a section running radially.

[0012] According to a further advantageous embodiment, it may be possible for the section extending obliquely to the tooth segment plane to be longer than the radially extending section. According to a further advantageous embodiment, it may be possible for the first and second connecting elements to be designed such that, in a connected state, the first and second connecting elements can be integrally connected at a radially outwardly projecting end of the connecting surface.

[0013] According to a further advantageous embodiment, it may be possible for the material connection between the first and second connecting element to be designed in the form of a welded connection.

[0014] Further advantages will become apparent from the following description of the figures. The figures illustrate various embodiments of the present invention.

[0015] The figures, the description, and the claims contain numerous features in combination. The skilled person will expediently consider the features individually and combine them into further meaningful combinations.

[0016] They show:

[0017] Figure 1 is a schematic side view of a machine tool with a drive according to an exemplary embodiment;

[0018] Figure 2 is a perspective side view of a stator and rotor as part of the drive;

[0019] Figure 3 is a perspective side view of the stator with a number of

[0020] dental equipment;

[0021] Figure 4 is a front view of four adjacent dental devices with a

[0022] Connecting device comprising a first and second connecting element according to a preferred embodiment; and

[0023] Figure 5 is a front view of two dental devices with the connecting device comprising a first and second connecting element according to the preferred embodiment in a separated state.

[0024] Examples of implementation:

[0025] Figure 1 shows a machine tool 1 in the form of a cordless screwdriver according to an exemplary embodiment.

[0026] Alternatively, the machine tool 1 can also be designed in the form of a hammer drill, a combination hammer, a drilling machine, a saw, a grinder or the like.

[0027] As shown in Figure 1, the machine tool 1 according to the exemplary embodiment essentially contains a housing 2, a tool holder 3, a handle 4 and a power supply 5.

[0028] The housing 2 has a top side 2a, a bottom side 2b, a front end 2c and a rear end 2d.

[0029] Positioned at the front end 2c of the housing 2 is the tool holder 3, which serves to receive and hold a tool 6. In the present case, the tool 6 is designed as a screwdriver bit (or simply called a bit).

[0030] The handle 4 serves to hold and guide the machine tool 1 by a user (not shown in the figures). The handle 4 has an upper end 4a, a lower end 4b, a front side 4c, and a rear side 4d. The upper end 4a of the handle 4 is connected to the underside 2b of the housing 2 of the machine tool 1.

[0031] As can be seen in Figure 1, an actuation switch 7 is positioned on the front side 4c of the handle 4. The actuation switch 7 is used to activate the machine tool 1.

[0032] A control device 8 of the machine tool 1 is positioned inside the handle 4 and serves to control and regulate the functions of the machine tool 1.

[0033] A foot device 8 with a machine tool interface 9 is provided on the underside 2b of the housing 2 of the machine tool 1. The machine tool interface 9 serves to releasably connect the machine tool 1 to the power supply 5.

[0034] In the present embodiment, the power supply 5 is designed as a rechargeable battery. According to an alternative embodiment not shown in the figures, the power supply 5 can also be designed as a power cable for releasably connecting the machine tool 1 to a mains power source (also called a power outlet).

[0035] Furthermore, a drive 10, a gear mechanism 11, and a drive shaft 12 are provided inside the housing 2 of the machine tool 1. In the present embodiment, the drive 10 is configured as an electric motor and serves to generate torque. The drive 10, configured as an electric motor, the gear mechanism 11, and the drive shaft 12 are arranged or positioned relative to one another in the housing 2 of the machine tool 1 such that a torque generated by the drive 10 can be transmitted via the gear mechanism 11, the drive shaft 12, and ultimately to the tool holder 3 and the tool 6.

[0036] The drive 10 essentially contains a cylindrical stator 13 and a cylindrical rotor 14 positioned in the stator 13 and rotatable relative to the stator 13, see Figure 2. The rotor 14 rotates about a central axis MA of the stator 13.

[0037] As can be seen in Figures 3 to 5, the stator 13 according to the exemplary embodiment contains six tooth devices 20.

[0038] According to alternative embodiments, the stator 13 may also contain more or fewer than six tooth devices 20.

[0039] Each individual toothed device 20 serves to receive and hold a coil winding 15 made of a conductive wire. The material of the conductive wire can be, for example, copper or a copper alloy.

[0040] Each tooth device 20 includes a web element 16 and an arcuate first ring section 17 and second ring section 18.

[0041] As can be seen in Figures 3 and 4, the individual ring sections 17, 18 form a closed, circular ring R when combined.

[0042] The web element 16 has a first end 16a and a second end 16b, wherein the coil winding 15 is mounted between the first and second ends 16a, 16b.

[0043] The respective first end 16a of the web element 16 is positioned on an inner surface of the ring R formed by the individual ring sections 17, 18. The second end 16b of the web element 16 projects to a center point M of the ring R. The length of the web elements 16 is selected such that a circular recess remains inside the stator 13. The rotor 14 can be placed in this recess.

[0044] As can be seen in the figures, both the first and second ring sections 17, 18 each have a first and second end 17a, 17b, 18a, 18b.

[0045] The first end 17a of the first ring section 17 is positioned at the first end 16a of the web element 16. The first end 18a of the second ring section 18 is also positioned at the first end 16a of the web element 16. The two ring sections 17, 18 extend in opposite directions around the ring R.

[0046] Figure 4 shows a toothed device 20 according to a first embodiment, wherein the first ring section 17 has a longer first circular arc KB1 than the second circular arc KB2 of the second ring section 18. In other words, the first ring section 17 has a larger volume than the second ring section 18. In the illustrated embodiment, the volume of the second ring section 18 corresponds substantially to 1 / 4 or 25% of the volume of the first ring section 17.

[0047] In addition, each tooth device includes a connecting device 19 with a first and second connecting element 19a, 19b. The first connecting element 19a is positioned on the first ring section 17, and the second connecting element 19b is positioned on the second ring section 18.

[0048] In the present embodiment, the connecting device 19 is designed as a joining connection. The connecting device 19, designed as a joining connection, serves to detachably connect the individual ring sections 17, 18 and thus the individual toothed device 20 to form a continuous annular stator 13.

[0049] The first and second connecting elements 19a, 19b are correspondingly wedge-shaped, so that in a connected state a first contact surface 21 of the first connecting element 19a, which runs obliquely to a tooth segment plane E, rests against a second contact surface 22 of the second connecting element 19b, which runs obliquely to the tooth segment plane E, cf. Figure 4. By connecting the first connecting element 19a to the second connecting element 19b, the first and second ring sections 17, 18 are connected to one another.

[0050] When the first and second connecting elements 19a, 19b are connected to each other, a connecting surface 24 between the first and second contact surfaces 21, 22 runs obliquely to the tooth segment plane E.

[0051] As shown in Figures 4 and 5, the connecting surface 24 has both a first section 24a extending obliquely to the tooth segment plane E and a second substantially radial section 24b.

[0052] Furthermore, the first and second connecting elements 19a, 19b each have a raised portion 23. Each raised portion 23 extends radially, or outwardly, from the outer surface of the stator 13. The raised portions 23 on the first and second connecting elements 19a, 19b have a circular arc of substantially equal length.

[0053] When the first and second connecting elements 19a, 19b are connected to one another, the two elevations 23 complement each other to form a substantially continuous elevation on the outer surface of the stator 13, said continuous elevation 23 having a substantially rectangular cross-sectional area.

[0054] The continuous elevation 23 on the outer surface of the stator 13 serves for the correct orientation or alignment of the stator 13 during assembly of a stator 13 to a drive 10 of a machine tool 1. Furthermore, a welded or adhesive bond can be applied to the elevation 23.

[0055] Reference symbol

[0056] 1 machine tool

[0057] 2 Machine tool housing

[0058] 2a Top of the machine tool housing

[0059] 2b Bottom of the machine tool housing

[0060] 2c front end of the machine tool housing

[0061] 2d rear end of the machine tool housing

[0062] 3 tool holder

[0063] 4 Handle

[0064] 4a upper end of the handle

[0065] 4b lower end of the handle

[0066] 4c Front of the handle

[0067] 4d Back of the handle

[0068] 5 Energy supply

[0069] 6 Tools

[0070] 7 operating switches

[0071] 8 Control device

[0072] 9 Machine tool interface

[0073] 10 Drive

[0074] 11 Gear device

[0075] 12 Drive shaft

[0076] 13 Stator

[0077] 14 Rotor

[0078] 15 coil winding

[0079] 16 web element

[0080] 16a first end of the web element

[0081] 16b second end of the web element

[0082] 17 first ring section

[0083] 17a first end of the first ring section

[0084] 17b second end of the first ring section 18 second ring section

[0085] 18a first end of the second ring section

[0086] 18b second end of the second ring section

[0087] 19 Connecting device

[0088] 19a first connecting element

[0089] 19b second connecting element

[0090] 20 Dental equipment

[0091] 21 first investment area

[0092] 22 second contact surface

[0093] 23 Survey

[0094] 24 connecting surface

[0095] 24a first section of the connecting surface

[0096] 24b second section of the connecting surface

[0097] E Tooth segment plane

[0098] M center

[0099] MA central axis

[0100] R circular ring

[0101] VS Liaison Office

[0102] KB1 first circular arc

[0103] KB2 second circular arc

[0104] VL connecting line

Claims

Patent claims 1. Stator (13) for an electric motor, in particular as a drive (10) for a machine tool (1), comprising at least a first and a second toothed device (20), each with a radially arranged web element (16) for receiving a coil winding (15), characterized in that each toothed device (20) contains an arcuate ring section (17, 18) and a connecting device (19) with a first and a second connecting element (19a, 19b), wherein the first and second connecting elements (19a, 19b) are correspondingly wedge-shaped, so that in a connected state a first contact surface (21, 22) of the first connecting element (19a), which runs obliquely to a tooth segment plane (E), bears against a second contact surface (21, 22) of the second connecting element (19b), which runs obliquely to the tooth segment plane (E).

2. Stator (13) according to claim 1, characterized in that the first and second connecting elements (19a, 19b) are designed such that a connecting surface (24) has both a section (24a) running obliquely to the tooth segment plane (E) and a section (24b) running radially.

3. Stator (13) according to claim 2, characterized in that the section (24a) extending obliquely to the tooth segment plane (E) is longer than the radially extending section (24b).

4. Stator (13) according to claim 2 or 3, characterized in that the first and second connecting elements (19a, 19b) are designed such that the first and second connecting elements (19a, 19b) can be connected in a materially bonded manner at a radially outwardly projecting end of the connecting surface (24) in a connected state.

5. Stator (13) according to claim 4, characterized in that the material connection between the first and second connecting elements (19a, 19b) is designed in the form of a welded connection.

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