Stator segment with deformable connecting elements

Abstract

A stator for an electric motor, in particular as a drive of a power tool, comprises at least one first toothed arrangement and one second toothed arrangement, each having a rod element for receiving a radial arrangement of coil windings. Each tooth-shaped arrangement comprises an arc-shaped ring section and a connecting device with a first connecting element and a second connecting element, the first connecting element comprises a deformable part, the second connecting element comprises a receiving area for receiving and holding the deformable part, and the deformable part is deformed when inserted into the receiving area, the first connecting element and the second connecting element are connected to each other in a form-fitting manner.

Description

[0001] The present invention relates to a stator for an electric motor, particularly as a drive device for a power tool, the stator comprising at least one first tooth arrangement and a second tooth arrangement, each of the first tooth arrangement and the second tooth arrangement having a rod element for receiving a radially arranged coil winding.

[0002] According to existing technology, the stator, as a component for an electric motor, essentially has a ring element and multiple toothed elements. The toothed elements extend from the circumferential inner surface of the ring element to the center point of the ring element. A circular gap for the rotor is maintained at the free end of the toothed element. Each toothed element is used to receive and hold a winding coil made of conductive coil wire to correspondingly generate a magnetic field.

[0003] Especially with smaller stators, winding individual tooth elements with coil wire typically involves a significant amount of technical effort. The available space between adjacent tooth elements is often narrow, making the rapid and, most importantly, neat winding of the coil around the tooth elements time-consuming, requiring meticulously crafted winding equipment, and incurring high costs.

[0004] Therefore, the purpose of this invention is to solve the above-mentioned problems.

[0005] This objective is achieved through the subject matter of independent claim 1.

[0006] Advantageous embodiments of the subject matter of the invention can be found in the dependent claims.

[0007] This objective is achieved in particular by a stator for an electric motor, especially as a drive unit for a power tool, the stator comprising at least one first tooth arrangement and a second tooth arrangement, each of the first tooth arrangement and the second tooth arrangement having a rod element for receiving a radially arranged coil winding.

[0008] According to the present invention, each toothed arrangement includes an arcuate ring segment and a connecting device having a first connecting element and a second connecting element, wherein the first connecting element includes a deformable portion and the second connecting element includes a receiving area for receiving and holding the deformable portion, and wherein the deformable portion deforms when inserted into the receiving area in such a way that the first connecting element and the second connecting element are connected to each other in a form-fitting manner.

[0009] The deformable parts can be configured plastically or elastically.

[0010] "Cooperation" can also be understood as referring to the precision or accuracy of cooperation.

[0011] According to another advantageous embodiment, the connecting device may include at least one first undercut and a second undercut.

[0012] According to another advantageous embodiment, the compensating element may at least partially comprise a curable material. The curable material may be, for example, a polymer, a synthetic resin, etc.

[0013] According to another advantageous embodiment, it is possible that the first connecting element is positioned at the free end of the arcuate ring section, and the second connecting element is positioned substantially at the first end of the rod element.

[0014] The dividing lines at the connection points required for the division of gear elements have a negative impact on the structural cohesion of the magnetic circuit and the stator as a whole. This can adversely affect the power density, stability, and / or noise behavior of the entire electric motor. In particular, the negative impact of dividing lines in the form of punched edges on the electromagnetic characteristics of the stator laminations must be considered.

[0015] To minimize these drawbacks, it has proven advantageous, according to another alternative embodiment, that at least one first connection point of the first and second connecting elements lies substantially in a plane passing through the toothed arrangement. This allows regions with high magnetic flux density through the stator's magnetic circuit to lie within the radial range of the toothed elements, thus optimizing the magnetic flux.

[0016] According to another advantageous embodiment, it is possible that the first and second connecting elements, in the closed state, at least produce a form-fit, press-fit, and / or material bond connection with each other. Therefore, the connecting elements can be connected in a simple manner. In addition to mechanical connections (i.e., form-fit or force-fit connections), a material bond connection in the form of an adhesive can also be provided between adjacent ring segments.

[0017] According to another advantageous embodiment, the connecting device may be configured as a snap-fit ​​connection. This makes it possible to achieve a reliable and releasable connection of the connecting elements in a simple manner.

[0018] According to another advantageous embodiment, the connecting device may be configured for an engaging connection. This allows for a simple releasable connection of the connecting elements, which does not require elastic deformation of the connecting elements or portions thereof. For releasable connection or disconnection, the connecting elements can simply abut against each other or shift relative to each other on the stator axis.

[0019] According to another advantageous embodiment, it is possible that at least one first dividing line of the engagement connection between the first connecting element and the second connecting element extends parallel to the central axis of the stator, such that the first connecting element and the second connecting element can abut against each other and shift parallel to the central axis of the stator. This makes it possible to achieve a relatively robust and load-bearing connection of the connecting elements in a simple manner.

[0020] According to another advantageous embodiment, it is possible that the distance between the dividing lines of the engagement connection between the first connecting element and the second connecting element is longer than the width of the toothed arrangement. This results in the longest possible connecting lines or dividing lines between adjacent connecting elements, thus minimizing the negative impact on the magnetic flux between the adjacent connecting elements.

[0021] According to another advantageous embodiment, a resiliently deformable or plastically deformable contact element may be disposed between the first connecting element and the second connecting element. This enables a reliable snap-fit ​​connection between adjacent connecting elements and the removal of individual toothed arrangements on the stator assembly in a simple manner.

[0022] Further advantages will become apparent from the following description of the accompanying drawings, which illustrate various exemplary embodiments of the invention.

[0023] The accompanying drawings, description, and claims contain many combinations of features. Those skilled in the art will also be able to consider these features individually and combine them to produce other useful combinations.

[0024] In the attached diagram:

[0025] Figure 1 A schematic side view of a power tool with a drive device according to an exemplary embodiment is shown;

[0026] Figure 2 A perspective side view of the stator and rotor, which are part of the drive unit, is shown;

[0027] Figure 3 A perspective side view of a stator with multiple toothed arrangements is shown;

[0028] Figure 4 A front view of two adjacent toothed arrangements with a connecting device according to a first embodiment in a separated state is shown, the connecting device including a first connecting element and a second connecting element;

[0029] Figure 5 A front view of two adjacent toothed arrangements with a connecting device according to a first embodiment is shown in a connected state, the connecting device including a first connecting element and a second connecting element;

[0030] Figure 6a A front view of two adjacent toothed arrangements with a connecting device according to a second embodiment is shown in a separated state, the connecting device including a first connecting element and a second connecting element;

[0031] Figure 6b A front view of two adjacent toothed arrangements with a connecting device according to a second embodiment in a deformed state is shown; the connecting device includes a first connecting element and a second connecting element; and

[0032] Figure 7 A front view of two adjacent toothed arrangements with a connecting device according to a second embodiment in a final connected state is shown, the connecting device including a first connecting element and a second connecting element. Detailed Implementation

[0033] Figure 1 A power tool 1 in the form of a rechargeable battery-operated screwdriver is shown according to an exemplary embodiment.

[0034] Power tool 1 can also be alternatively designed in the form of a hammer drill, combination hammer, power drill, saw, grinder, etc.

[0035] like Figure 1 As shown, the power tool 1 according to an exemplary embodiment basically includes a housing 2, a tool accessory 3, a handle 4, and a power supply device 5.

[0036] The housing 2 has a top side 2a, a bottom side 2b, a front end 2c, and a rear end 2d.

[0037] Tool accessory 3 for receiving and holding tool 6 is positioned at the front end 2c of housing 2. In the present case, tool 6 is in the form of a screwdriver tip (or simply a tip).

[0038] The handle 4 allows the user (not shown in the attached drawings) to hold and guide the power tool 1. 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 bottom side 2b of the housing 2 of the power tool 1.

[0039] As in Figure 1 As can be seen, the actuation switch 7 is located on the front side 4c of the handle 4. The actuation switch 7 is used to activate the power tool 1. The control device 8 of the power tool 1 is located inside the handle 4 and is used to control and adjust the function of the power tool 1.

[0040] A base device 8 having a power tool interface 9 is disposed on the bottom side 2b of the housing 2 of the power tool 1. The power tool interface 9 is used to releasably connect the power tool 1 to the power supply device 5.

[0041] In this embodiment, the power supply device 5 is in the form of a rechargeable battery. According to an alternative embodiment (not shown in the drawings), the power supply device 5 may also be configured as a cable for releasably connecting the power tool 1 to an AC power source (also known as an electrical outlet).

[0042] The housing 2 of the power tool 1 also houses a drive unit 10, a transmission device 11, and a drive shaft 12. In this exemplary embodiment, the drive unit 10 is in the form of an electric motor and is used to generate torque. The drive unit 10, transmission device 11, and drive shaft 12, which are in the form of electric motors, are arranged or positioned relative to each other in the housing 2 in such a way that the torque generated by the drive unit 10 can be transmitted via the transmission device 11 and the drive shaft 12 and ultimately transmitted to the tool accessory 3.

[0043] The drive unit 10 further comprises essentially a stator 13 and a rotor 14, the rotor being positioned within the stator 13 and rotatable relative to the stator 13, see [link to previous section]. Figure 2 The rotor 14 rotates around the central axis MA of the stator 13.

[0044] As in Figures 3 to 5 As can be seen, the stator 13 includes six tooth arrangements 20 according to an exemplary embodiment. According to alternative embodiments, the stator 13 may also include more or fewer than six tooth arrangements 20.

[0045] Each individual toothed arrangement 20 is used to receive a coil winding 15 made of conductive wire. For example, the conductive wire may be made of copper or a copper alloy.

[0046] Each toothed arrangement 20 includes a rod element 16, and an arc-shaped first ring segment 17 and a second ring segment 18. (As in...) Figure 3 and Figure 4 As can be seen, the individual ring segments 17 and 18 combine to form a closed ring R.

[0047] The rod element 16 has a first end 16a and a second end 16b, with the coil winding 15 attached between the first end 16a and the second end 16b. The corresponding first end 16a of the rod element 16 is positioned on the circumferential inner surface of the ring R formed by the respective ring segments 17, 18. The second end 16b of the rod element 16 protrudes to the center point M of the ring R. The length of the rod element 16 is chosen such that a circular recess remains inside the stator 13. The rotor 14 can be placed within said recess.

[0048] As can be seen in the accompanying drawings, the first ring segment 17 and the second ring segment 18 each have a first end and a second end 17a, 17b, 18a, 18b. The first end 17a of the first ring segment 17 is located at the first end 16a of the rod element 16. The first end 18a of the second ring segment 18 is also located at the first end 16a of the rod element 16. The two ring segments 17 and 18 extend in opposite directions around the ring R.

[0049] Figure 4A toothed arrangement 20 according to a first embodiment is shown, wherein the first ring segment 17 has a first arc KB1 that is longer than the second arc KB2 of the second ring segment 18. In other words, the first ring segment 17 has a larger volume than the second ring segment 18. In the exemplary embodiment shown, the volume of the second ring segment 18 is substantially one-quarter or 25% of the volume of the first ring segment 17.

[0050] Additionally, each toothed arrangement includes a connecting device 19 having a first connecting element 19a and a second connecting element 19b. The first connecting element 19a is positioned on the first ring segment 17, and the second connecting element 19b is positioned on the second ring segment 18.

[0051] In this exemplary embodiment, the connecting device 19 is configured for engagement connection. The connecting device 19 configured for engagement connection is used to releasably connect the respective ring segments 17, 18, and thus connect the respective toothed arrangements 20 to form a continuous annular stator 13.

[0052] The first connecting element 19a on the first ring segment 17 is configured as a deformable portion. The deformable portion can be configured plastically or elastically. In the first embodiment, the deformable portion of the first connecting element 19a is substantially in the form of a radially inwardly pointing pin.

[0053] exist Figure 4 In the diagram, the first connecting element 19a, and in particular the plastically deformable portion of the first connecting element 19a, is shown in its original or undeformed state.

[0054] The second connecting element 19b on the second ring segment 18 is further configured as a receiving area, which is configured to receive the first connecting element 19a configured as a pin. See below. Figure 4 The volume of the receiving area is slightly larger than the volume of the pin, and therefore the undeformed pin can be positioned within the receiving area with slight clearance.

[0055] exist Figure 4 In the diagram, the first connecting element 19a and the second connecting element 19b are shown in a separated state, wherein the first connecting element 19a and the second connecting element 19b are not engaged with each other.

[0056] To connect the first connecting element 19a and the second connecting element 19b, the first connecting element 19a, configured as a pin, is as follows: Figure 4The first connecting element 19a, configured as a pin, is drawn downwards in the radial direction into the second connecting element 19b, which is configured as the receiving area. When the first connecting element 19a, configured as a pin, is located in the second connecting element 19b, configured as the receiving area, a certain force is applied downwards in the radial direction to the first connecting element 19a, configured as a pin. By means of this applied force, the pin deforms and takes on the shape of the receiving area, see [reference needed]. Figure 5 Therefore, the first connecting element 19a and the second connecting element 19b are in a form-fit connection.

[0057] In addition, Figure 4 As can be seen, the first connecting element 19a has a first contact surface 21a extending obliquely relative to the tooth segment plane E, and the second connecting element has a second contact surface 21b extending obliquely relative to the tooth segment plane E. When the first connecting element 19a and the second connecting element 19b are connected to each other, the connecting line between the first contact surface and the second contact surface extends obliquely relative to the tooth segment plane E.

[0058] Additionally, the first connecting element 19a and the second connecting element 19b each have protrusions 23a, 23b. Each protrusion 23a, 23b extends outward in the radial direction or from the circumferential outer surface of the stator 13. The protrusion 23a on the first connecting element 19a includes a long arc, and the protrusion 23b on the second connecting element 19b includes a short arc. Figure 4 As can be seen, the protrusions 23a, 23b of the first connecting element 19a and the second connecting element 19b have side surfaces that extend substantially radially outward.

[0059] However, the protrusions 23a and 23b on the first connecting element 19a and the second connecting element 19b may also have arcs of substantially the same length.

[0060] When the first connecting element 19a and the second connecting element 19b are connected to each other, the two protrusions 23a, 23b complement each other to form a substantially continuous protrusion 23 on the circumferential outer surface of the stator 13, the continuous protrusion 23 having a substantially rectangular cross-sectional area.

[0061] The continuous protrusions 23 on the circumferential outer surface of the stator 13 are used for the correct orientation or alignment of the stator 13 during installation of the drive unit 10 for the power tool 1.

[0062] Figure 6a The toothed arrangement 20 according to the second embodiment is shown in a separated state.

[0063] According to the second embodiment, the toothed arrangement 20 basically corresponds to Figure 5The first embodiment is shown. Similarly, in the second embodiment, the first ring segment 17 has a first arc KB1 that is longer than the second arc KB2 of the second ring segment 18.

[0064] Compared to the first embodiment, in the second embodiment, the deformable portion of the first connecting element 19a is substantially in the form of a ring. The ring has a circular opening.

[0065] exist Figure 6b In this process, a certain force is applied radially downwards to a first connecting element 19a configured as a ring. This force deforms the ring into an elongated elliptical shape so that it can be brought into a second connecting element 19b configured as a receiving area. The material of the first connecting element 19a is softer than the material of the second connecting element 19b, such that when a force is applied radially downwards, only the first connecting element 19a deforms, while the second connecting element 19b remains unchanged.

[0066] Figure 7 A first connecting element 19a and a second connecting element 19b in a connected state are shown. When the first connecting element 19a, configured as a ring, is fully located within the receiving area of ​​the second connecting element 19b due to the application of force, the first connecting element 19a, configured as a deformed ring, returns to a certain ring shape by the application of a certain force in the radial direction N. In this way, the first connecting element 19a adapts to the shape of the second connecting element 19b, and thus the first connecting element 19a and the second connecting element 19b are in a form-fit connection and are therefore radially guided.

[0067] A cylindrical insert element in the form of a stud with a circular cross-sectional area is then inserted into the opening in the second connecting element 19b.

[0068] Figure Labels

[0069]

[0070] .

Claims

1. A stator (13) for an electric motor, particularly as a drive unit for a power tool, the stator comprising at least one first tooth arrangement and a second tooth arrangement (20), each of the first tooth arrangement and the second tooth arrangement having a rod element for receiving a radially arranged coil winding. Its features are, Each toothed arrangement (20) includes an arcuate ring segment and a connecting device (19) having a first connecting element (19a) and a second connecting element (19b), wherein the first connecting element (19a) includes a deformable portion and the second connecting element (19b) includes a receiving area for receiving and holding the deformable portion, wherein the deformable portion deforms when inserted into the receiving area in such a way that the first connecting element (19a) and the second connecting element (19b) are connected to each other in a form-fitting manner.

2. The stator (13) as described in claim 1. Its features are, The first connecting element (19a) is positioned at the free end of the arc-shaped ring section, and the second connecting element (19b) is positioned substantially at the first end of the rod element (19a, 19b).

3. The stator (13) as described in claim 1 or 2. Its features are, The connecting device (19) is configured for a mating connection.

4. The stator (13) as described in at least one of claims 1 to 3. Its features are, The distance between the dividing line of the engagement connection between the first connecting element (19a) and the second connecting element (19b) is longer than the width (ZB) of the toothed arrangement (20).

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