Stator segment with t-profile

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 connecting element has a first contact surface, which runs diagonally to a tooth segment plane, and a T-shaped part, and the second connecting element has a second contact surface, which runs diagonally to the tooth segment plane, and a T-shaped receiving region. The first and second contact surface and the T-shaped part and T-shaped receiving region are designed such that the first and second connecting element can be connected together in a form-fitting manner.

Description

[0001] Stator segment with T-profile

[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 coil wire is usually a complex technical undertaking. The available space between adjacent tooth elements is often limited, 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 a second connecting element, wherein the first connecting element comprises a first contact surface running obliquely to a tooth segment plane and a T-shaped portion, and the second connecting element comprises a second contact surface running obliquely to the tooth segment plane and a T-shaped receiving area, and wherein the first and second contact surfaces and the T-shaped portion and the T-shaped receiving area are designed such that the first and second connecting elements can be connected to one another in a form-fitting manner.

[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 connecting device to contain at least a first and a second undercut.

[0012] According to a further advantageous embodiment, it may be possible for the compensating element to at least partially contain a curable material. The curable material may be, for example, a polymer, synthetic resin, or the like.

[0013] According to a further advantageous embodiment, it may be possible for the first connecting element to be positioned at a free end of the arcuate ring section and the second connecting element to be positioned substantially at a first end of the web element.

[0014] The dividing lines between the connecting points required to divide the tooth elements impair the magnetic circuit and the structural integrity of the stator as a whole. This can adversely affect the power density, stability, and / or noise behavior of the entire electric motor. Particularly in the case of dividing lines formed as punched edges, their negative influence on the electromagnetic properties of a stator lamination must be considered.

[0015] To minimize these disadvantages, it has proven advantageous that, according to a further alternative embodiment, at least one first connection point of the first and second connecting elements lies substantially in a plane through a toothed device. This allows a region of the magnetic circuit through the stator with a high magnetic flux density to lie in the radial extension of a toothed element, thereby optimizing the magnetic flux.

[0016] According to a further advantageous embodiment, it may be possible for the first and second connecting elements to create at least one positive, non-positive and / or material-locking connection to one another in a closed state. This makes it possible to connect the connecting elements in a simple manner. In this case, in addition to a mechanical connection, i.e. a positive or non-positive connection, it is also possible to provide a material-locking connection in the form of an adhesive between the adjacent ring sections. According to a further advantageous embodiment, it may be possible for the connecting device to be designed as a snap connection. This makes it possible to achieve a reliable and removable connection between the connecting elements in a simple manner.

[0017] According to a further advantageous embodiment, it may be possible for the connecting device to be designed as a joining connection. This allows a releasable connection of the connecting elements to be achieved in a simple manner, which does not require elastic deformability of the connecting elements or parts of the connecting elements. For releasable connection or separation, the connecting elements can simply be displaced relative to or against each other along a stator axis.

[0018] According to a further advantageous embodiment, it may be possible for at least a first dividing line of the joint between the first and second connecting elements to run parallel to a central axis of the stator, so that the first and second connecting elements can be displaced relative to one another and parallel to the central axis of the stator. This allows a relatively secure and resilient connection of the connecting elements to be achieved in a simple manner.

[0019] According to a further advantageous embodiment, it may be possible for the path of the separating line of the joining connection between the first and second connecting elements to be longer than the width of a toothed device. This results in the longest possible connecting line or separating line between adjacent connecting elements, whereby the magnetic flux between these adjacent connecting elements is minimally negatively affected.

[0020] Further advantages will become apparent from the following description of the figures. The figures illustrate various embodiments of the present invention.

[0021] 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.

[0022] They show:

[0023] Figure 1 is a schematic side view of a machine tool with a drive according to an exemplary embodiment;

[0024] Figure 2 is a perspective side view of a stator and rotor as part of the drive;

[0025] Figure 3 is a perspective side view of the stator with a number of

[0026] dental equipment;

[0027] Figure 4 is a front view of two adjacent dental devices with a

[0028] Connecting device comprising a first and second connecting element according to an exemplary embodiment; and

[0029] Figure 5 is a front view of two adjacent dental devices with a connecting device containing a first and second connecting element according to a further exemplary embodiment.

[0030] Examples of implementation:

[0031] Figure 1 shows a machine tool 1 in the form of a cordless screwdriver according to an exemplary embodiment.

[0032] Alternatively, the machine tool 1 can also be designed in the form of a hammer drill, combination hammer, drilling machine, saw, grinder or the like.

[0033] 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.

[0034] The housing 2 has a top side 2a, a bottom side 2b, a front end 2c and a rear end 2d.

[0035] 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).

[0036] 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.

[0037] As can be seen in Figure 1, an actuating switch 7 is positioned on the front side 4c of the handle 4. The actuating switch 7 serves to activate the machine tool 1. 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.

[0038] 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.

[0039] 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).

[0040] 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 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.

[0041] The drive 10 essentially contains a stator 13 and a 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.

[0042] As can be seen in Figures 3 to 5, the stator 13 according to the exemplary embodiment contains six tooth devices 20. According to alternative embodiments, the stator 13 can also contain more or fewer than six tooth devices 20.

[0043] Each individual toothed device 20 serves to accommodate a coil winding 15 made of a conductive wire. The material of the conductive wire can be, for example, copper or a copper alloy.

[0044] Each tooth device 20 includes a web element 16 as well as an arcuate first ring section 17 and second ring section 18. As can be seen in Figures 3 and 4, the individual ring sections 17, 18 form a closed, circular ring R when combined.

[0045] The web element 16 has a first end 16a and a second end 16b, with the coil winding 15 being mounted between the first and second ends 16a, 16b. 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.

[0046] 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. 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] As shown in Figure 4, the joining connection on the connecting device 19 forms a parting line in the connected state. The path of the parting line between the first and second connecting elements 19a, 19b is longer than a width ZB of a toothed device 20.

[0051] The first connecting element 19a on the first ring section 17 is essentially designed in the form of a first contact surface 21 extending obliquely to a tooth segment plane E and a T-shaped portion.

[0052] The second connecting element 19b on the second ring section 18 is again designed in the form of a second contact surface 22 running obliquely to the tooth segment plane E and a T-shaped receiving area

[0053] As shown in Figure 4, the first and second contact surfaces 21, 22 as well as the T-shaped portion and the T-shaped receiving area are designed such that the first and second connecting elements 19a, 19b can be connected to one another in a form-fitting manner. Figure 4 shows the first and second connecting elements 19a, 19b in a connected state.

[0054] By the engagement of the first connecting element 19a in the second connecting element 19b, the first and second ring sections 17, 18 are connected to one another.

[0055] In addition, the first and second connecting elements 19a, 19b each have a first and second elevation 23a, 23b. Each elevation 23a, 23b extends in the radial direction or outward from the outer surface of the stator 13. The elevation 23a on the first connecting element 19a contains a long circular arc KB3, and the elevation 23b on the second connecting element 19b contains a short circular arc KB4. As can be seen in Figure 4, both the elevation 23a, 23b of the first and second connecting elements 19a, 19b have a side surface that extends substantially radially outward.

[0056] However, the elevations 23a, 23b on the first and second connecting elements 19a, 19b can also have a circular arc of substantially equal length.

[0057] When the first and second connecting elements 19a, 19b are connected to one another, the two elevations 23a, 23b complement one another to form a substantially continuous elevation 23 on the outer surface of the stator 13, said continuous elevation 23 having a substantially rectangular cross-sectional area.

[0058] 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 to a drive 10 on a machine tool 1. A welded or adhesive connection can also be made to the continuous elevation 23.

[0059] Figure 5 shows a connecting device 19 according to a further embodiment. The T-shaped receiving area of ​​the second connecting element 19b has a larger volume, so that in a connected state, ie, when the T-shaped portion is positioned in the T-shaped receiving area, a free space FR remains.

[0060] Furthermore, the T-shaped receiving area contains a first and second joining element 24a, 24b. As can be seen in the figure, the two joining elements 24a, 24b are mounted opposite one another on the side walls of the T-shaped receiving area. The first and second joining elements 24a, 24b are made of an elastically deformable material, e.g., an elastomer. According to a further embodiment, the first and second joining elements 24a, 24b can also be made of a plastically deformable material.

[0061] As also indicated in Figure 5, the first and second joining elements 24a, 24b serve to hold the T-shaped portion when the T-shaped portion is located in the T-shaped receiving area. By inserting the T-shaped portion into the T-shaped receiving area, the respective joining elements 24a, 24b are pressed together or compressed. As also indicated in Figure 5, a first distance D1 between the first and second joining elements 24a, 24b in a relaxed state (i.e., non-compressed state) is reduced to a second, smaller distance D2 between the first and second joining elements 24a, 24b in a compressed state. A first original height H1 of the first and second joining elements 24a, 24b in a relaxed state (ie, non-compressed state) decreases to a second height H2 in a compressed state of the first and second joining elements 24a, 24b.The free space FR between the T-shaped portion and the T-shaped receiving area can additionally be filled with a liquid or curable plastic (i.e. adhesive) to provide additional stability.

[0062] Reference symbol

[0063] 1 machine tool

[0064] 2 Machine tool housing

[0065] 2a Top of the machine tool housing

[0066] 2b Bottom of the machine tool housing

[0067] 2c front end of the machine tool housing

[0068] 2d rear end of the machine tool housing

[0069] 3 tool holder

[0070] 4 Handle

[0071] 4a upper end of the handle

[0072] 4b lower end of the handle

[0073] 4c Front of the handle

[0074] 4d Back of the handle

[0075] 5 Energy supply

[0076] 6 Tools

[0077] 7 operating switches

[0078] 8 Control device

[0079] 9 Machine tool interface

[0080] 10 Drive

[0081] 11 Gear device

[0082] 12 Drive shaft

[0083] 13 Stator

[0084] 14 Rotor

[0085] 15 coil winding

[0086] 16 web element

[0087] 16a first end of the web element

[0088] 16b second end of the web element

[0089] 17 first ring section

[0090] 17a first end of the first ring section

[0091] 17b second end of the first ring section 18 second ring section

[0092] 18a first end of the second ring section

[0093] 18b second end of the second ring section

[0094] 19 Connecting device

[0095] 19a first connecting element

[0096] 19b second connecting element

[0097] 20 Dental equipment

[0098] 21 first investment area

[0099] 22 second contact surface

[0100] 23 continuous elevation

[0101] 23a first survey

[0102] 23b second survey

[0103] 24a first joining element

[0104] 24b second joining element

[0105] D1 first distance between the joining elements

[0106] D2 second distance between the joining elements

[0107] H1 first height of a joining element

[0108] H2 second height of a joining element

[0109] E Tooth segment plane

[0110] M center

[0111] MA central axis

[0112] R circular ring

[0113] VS Liaison Office

[0114] KB1 first circular arc

[0115] KB2 second circular arc

[0116] KB3 third circular arc

[0117] KB4 fourth circular arc

[0118] FR Free space

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 (19a, 19b) 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 connecting element (19a) has a first contact surface (21) running obliquely to a tooth segment plane (E) and a T-shaped portion, and the second connecting element (19b) has a second contact surface (22) running obliquely to the tooth segment plane and a T-shaped receiving area, and wherein the first and second contact surfaces (21, 22) and the T-shaped portion and the T-shaped receiving area are designed such that the first and second connecting elements (19a,19b) can be connected to each other in a form-fitting manner., 2. Stator (13) according to claim 1, characterized in that at least a first connection point (VS) of the first and second connecting elements (19a, 19b) lies substantially in the tooth segment plane (E) by a tooth device (20).

3. Stator (13) according to claim 1 or 2, characterized in that the connecting device (19) is designed as a snap connection.

4. Stator (13) according to at least one of claims 1 to 3, characterized in that the connecting device (19) is designed as a joining connection.

5. Stator (13) according to at least one of claims 1 to 4, characterized in that at least a first parting line of the joining connection between the first and second connecting elements (19a, 19b) runs parallel to a central axis of the stator (13), so that the first and second connecting elements (19a, 19b) are displaceable relative to one another and parallel to the central axis of the stator (13).

6. Stator (13) according to at least one of claims 1 to 5, characterized in that the path length of the separating line of the joining connection between the first and second connecting element (19a, 19b) is longer than a Width (ZB) of a tooth device (20).

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