Electric motor

Abstract

An electric motor is disclosed having a stator (1), a rotor (2) and a shaft (3) attached to the rotor (2), the shaft being supported by a rolling bearing. According to the utility model, the rolling bearing is a double-row angular rolling bearing (4).

Description

Technical Field

[0001] The utility model relates to an electric motor. The electric motor comprises a stator, a rotor and a shaft attached to the rotor. The shaft is supported by rolling bearings. The features of the electric motor are known from, for example, US Pat. No. 11374465 B2. Background Art

[0002] A constant goal in developing electric motors is to fit the shaft into the most compact design with the smallest possible clearance at the lowest possible cost. This is often difficult because electric motors use multiple components made of different materials (e.g., aluminum and steel) with different coefficients of thermal expansion. This leads to mechanical stresses and relative motion when the operating temperature varies significantly.

[0003] Problems associated with thermal expansion can be reduced by supporting the shaft with rolling bearings arranged outside the stator, as in the motor known from US Pat. No. 11,374,465 B2. This largely avoids overheating of the bearings due to waste heat from the rotor or stator. However, this makes compact design of the motor more difficult. Utility Model Content

[0004] One object of the present invention is to describe how to mount a shaft in a compact electric motor with little clearance at low cost.

[0005] The electric motor according to the present invention comprises a double row angular rolling bearing to support the shaft. In this way, clearances can be avoided to a large extent and a compact design can be achieved.

[0006] An advantageous refinement of the present invention provides an angular rolling bearing having two rows of rolling elements, the two rows of rolling elements abutting different components on radial sides and the same component on opposite sides. For example, the angular rolling bearing may have a multi-part outer or inner ring, with only one of the two rows of rolling elements making contact with this outer or inner ring, while the other row of rolling elements makes contact with another component, such as a shaft. By having the two rows of rolling elements contact a total of three different components, play in the bearing can be advantageously minimized.

[0007] An advantageous refinement of the present invention provides that at least one of the two rows of rolling elements of the angular rolling bearing abuts the shaft. This allows the angular rolling bearing and shaft to be combined to form a compact assembly with few components. Preferably, the shaft has a recess into which the inner ring fits. The inner ring abuts one of the two rows of rolling elements of the angular rolling bearing, while the other row of rolling elements abuts directly against the shaft. This minimizes play in the bearing, particularly by fitting the preloaded inner ring into the recess of the shaft.

[0008] As an alternative to fitting the inner ring into a groove in the shaft, the inner ring can also be fixed by a material or friction connection. In this case, the inner ring can be connected directly to the shaft or connected to the shaft via another ring. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] With reference to the accompanying drawings, further details and advantages of the present invention will be explained with reference to embodiments of the present invention.

[0010] Figure 1 A cross-sectional view of an embodiment of a motor according to the present invention is shown. DETAILED DESCRIPTION

[0011] Figure 1 The motor shown comprises a stator 1 having a stator winding and a rotor 2 having permanent magnets surrounding the stator 1. The motor shown is therefore an outer rotor motor.

[0012] Rotor 2 is attached to shaft 3, which is supported by a double-row angular contact rolling bearing 4. The rolling elements of angular contact rolling bearing 4 can be, for example, balls or other rolling bodies, such as cones. Angular contact rolling bearing 4 includes an outer ring 5 and two rows of rolling elements 6 and 7, with outer ring 5 extending over rolling elements 6 and 7. Outer ring 5 has a projection 5a that extends radially inward between the two rows of rolling elements 6 and 7. The two rows of rolling elements 6 and 7 abut the projection 5a of outer ring 5 on opposite sides.

[0013] like Figure 1 As shown, angular rolling bearing 4 includes an inner ring 8, which abuts one of the two rows of rolling elements 6 and 7, namely row 7. The other row of rolling elements 6 directly abuts shaft 3. Inner ring 8 fits into a groove in shaft 3. Inner ring 8 forms a stop against which one of the two rows of rolling elements, namely row 7, abuts and is thus axially fixed. The other row of rolling elements 6 rests on a protrusion formed by shaft 3. Thus, angular rolling bearing 4 supports shaft 3 over a relatively long length, making it more difficult for shaft 3 to tilt.

[0014] The outer ring 5 may have an annular shoulder 9 forming a stop for the axial positioning of the angular rolling bearing 4. The annular shoulder 9 may abut, for example, the stator 1, a housing part 10 surrounding the stator 1 or another component of the electric motor fixed relative to the stator 1.

[0015] The angular rolling bearing 4 , or more precisely the outer ring 5 of the angular rolling bearing 4 , can be fixed relative to the stator 1 in the stator housing, for example, using a clamping ring or screws.

[0016] This design of the angular rolling bearing 4 allows for simple adjustment of the axial clearance with very little play and an advantageously compact design. In particular, the angular rolling bearing 4 can be preloaded, and the axial clearance is thereby reduced to zero. The angular rolling bearing 4 can be arranged completely within the stator 1, resulting in an advantageously compact design.

[0017] The shaft 3 can be designed as a hollow shaft to reduce weight. In the embodiment shown, the stator 1 and the rotor 2 are arranged in a two-part housing having a pot-shaped housing part 11 and a housing part 10 that closes the housing part 11. The shaft 3 extends from the pot-shaped housing part 11. Thus, the stator 1 and the rotor 2 can be arranged in a sealed interior, protected from water and the environment.

[0018] Reference Signs List

[0019] 1st stator

[0020] 2 rotors

[0021] 3-axis

[0022] 4-angle rolling bearing

[0023] 5 Outer Ring

[0024] 5a protrusion

[0025] 6 rows of rolling elements

[0026] 7 A row of rolling elements

[0027] 8Inner Ring

[0028] 9 Shoulders

[0029] 10 Shell part

[0030] 11 Shell part

Claims

1. An electric motor having stator (1), a rotor (2), and A shaft (3) attached to the rotor (2), the shaft (3) being supported by rolling bearings, characterized in that The rolling bearing is a double-row angular rolling bearing (4) comprising an outer ring (5) extending over two rows of rolling elements (6, 7) and an inner ring (8) extending over only one of the two rows of rolling elements (6, 7).

2. The electric motor according to claim 1, wherein The two rows of rolling elements (6, 7) abut different components on radial sides and rest against the same component on opposite sides.

3. The electric motor according to claim 1, wherein One row (6) of the two rows of rolling elements (6, 7) abuts the shaft (3), and the other row (7) of the two rows of rolling elements (6, 7) abuts the inner ring (8).

4. The electric motor according to claim 1, wherein The outer ring (5) has a projection (5a) which projects between the two rows of rolling elements (6, 7) and abuts the two rows of rolling elements (6, 7) on opposite sides.

5. The electric motor according to claim 4, characterized in that The shaft (3) has a stopper which, together with the projection (5a) of the outer ring (5), axially fixes one row (6) of the two rows of rolling elements (6, 7).

6. The electric motor according to claim 4, characterized in that The inner ring (8) has a stopper which, together with the projection (5a) of the outer ring (5), axially fixes one row (7) of the two rows of rolling elements (6, 7).

7. The electric motor according to claim 1, wherein The inner ring (8) is fitted into a groove of the shaft (3).

8. The electric motor according to claim 1, wherein The outer ring (5) has a shoulder (9) which forms a stop for the axial positioning of the double row angular rolling bearing (4).

9. The electric motor according to claim 1, wherein The double-row angular rolling bearing (4) is a ball bearing.

10. The electric motor according to claim 1, wherein The double-row angular rolling bearing (4) is fixed with a snap ring.

11. The electric motor according to claim 1, wherein The double-row angular rolling bearing (4) is fixed by screws.

12. The electric motor according to claim 1, wherein The shaft (3) is a hollow shaft.

13. The electric motor according to claim 1, wherein The rotor (2) is an outer rotor surrounding the stator (1).

14. The electric motor according to claim 1, wherein The double-row angular rolling bearing (4) is surrounded by the stator (1) over its entire length.

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