EP3465882A1

EP3465882A1 - End shield for a brushless electric motor

Info

Publication number: EP3465882A1
Application number: EP17719589.8A
Authority: EP
Inventors: Thomas Mahler; Manfred Jakob; Torsten Tussing
Original assignee: Hilti AG
Current assignee: Hilti AG
Priority date: 2016-05-30
Filing date: 2017-04-26
Publication date: 2019-04-10
Also published as: WO2017207173A1; CN109314429A; CN109314429B; US20190296603A1; EP3252931A1; US11699934B2

Abstract

The invention relates to a non-output-side end shield (100) for a brushless electric motor (500), comprising a centrally arranged bearing seat (110) for holding a non-output-side rotor bearing (510) for a rotor shaft (560) of the brushless electric motor (500), wherein the non-output-side end shield (100) has a sensor mount (150), which serves as a carrier for a sensor circuit board (550) for sensing the rotational position of the rotor shaft (560), wherein the non-output-side end shield (100) and the sensor mount (150) are formed together as a single-part component.

Description

Hilti Aktiengesellschaft in Schaan Principality of Liechtenstein

"Shield for a brushless electric motor"

The present invention relates to a non-output bearing plate for a brushless electric motor, with a centrally disposed bearing seat for receiving a non-output rotor bearing for a rotor shaft of the brushless electric motor. The invention also relates to a brushless electric motor with a non-driven end shield.

Non-output end shields and brushless electric motors with non-output end shields are basically known from the prior art. Non-output end shields are used in particular for receiving and supporting a rotor shaft of the brushless electric motor. This must be sufficiently accurately positioned and aligned relative to a stator lamination of the brushless electric motor. At the same time it is desirable that a sensor board for rotational position detection of the rotor shaft is in turn positioned and aligned sufficiently accurate to allow the most accurate commutation of the brushless electric motor. It is an object of the present invention to provide a non-output end shield that favors accurate positioning and alignment of a rotor shaft or a sensor board.

The object is achieved in that the non-output bearing plate has a sensor receptacle, which serves as a carrier for a sensor board for rotational position detection of the rotor shaft, wherein the non-output side bearing plate and the sensor receptacle are formed together as a one-piece component.

In a particularly preferred embodiment, the non-output side bearing plate has three equally spaced insertion elements, which are at least partially receiving in a corresponding insertion element corresponding insertion opening, which is a stator laminated core of the electric motor associated formed.

In this regard, it has been recognized that accurate positioning and alignment of the non-output bearing shield to the stator lamination stack, the rotor shaft, the sensor board as well as with respect to a sensor magnet ring is a special technical challenge. Typically, required tolerances are very low, so that the exact positioning and alignment of the non-driven side bearing plate takes a lot of time and money in the production of a brushless electric motor. In particular, it has been recognized that in a sequential assembly of individual components of the brushless electric motor, ie in particular when joining the non-output side bearing plate to stator laminated core, the rotor shaft, the sensor board and the sensor magnet ring can often lead to an unavoidable error chain that exceeds the required tolerances. It has been shown that in the case of non-driven end shields of the prior art, in particular the vote of the sensor ring and the sensor board are adversely affected. Accordingly, brushless electric motors of the prior art which have conventional non-output side end shields are often not optimally commutated.

By the three equally spaced slide-in elements, which are arranged on the non-output side bearing plate, wherein the non-output side bearing plate and the sensor receptacle are formed together as a one-piece component, the exact positioning and alignment of the components described is greatly facilitated.

It has proved to be advantageous if the non-output side bearing plate has exactly three equally spaced insertion elements, which are formed as a one-piece component with the non-output side bearing plate.

The non-output side bearing plate can be made of plastic, for example by injection molding. Alternatively, the non-output bearing plate can be made of metal, for example aluminum, preferably by milling.

It has proven to be advantageous if each of the insertion elements has a radially oriented and preferably plane centering surface which is provided for concentric centering of the insertion element with respect to the stator lamination stack. In the installed state, the centering surface preferably bears against a radial support surface of the stator lamination stack.

In a further preferred embodiment, each of the insertion elements has two tangentially oriented and preferably plane centering surfaces, which are provided for the angular orientation of the insertion element with respect to the stator lamination stack. Preferably, the lie plan centering surfaces in the installed state on a respective tangential support surface of the laminated stator core. In the context of the present invention, an angular orientation is to be understood as meaning an orientation of the non-output-side end plate with respect to the stator lamination stack, the angle being related to a direction of rotation of the rotor shaft. In a likewise preferred embodiment, each of the insertion elements on an axially oriented and preferably planar support surface, which is provided for maintaining a defined axial position between the non-output side bearing plate with respect to the stator lamination. Preferably, the planar support surface in the installed state bears against a preferably flat axial support surface of the stator lamination stack. An installation state is to be understood in the context of the present invention, such a state in which the non-output side end shield is disposed on a stator lamination of the brushless electric motor, in other words, the brushless electric motor is ready.

It has proved to be advantageous if the non-output side bearing plate has three equally spaced support members. The holding elements preferably each form a riot for a clamping screw, which is provided for connecting the non-output side bearing plate with a Abtnebsseitigen bearing plate.

It has proved to be advantageous if the non-driven rotor bearing is designed as a roller bearing. The invention is also achieved by a brushless electric motor with a laminated stator core, a Abtnebsseitigen end shield, a prescribed not abtnebsseitigen end shield and a rotor shaft which is mounted in a Abtnebsseitigen rotor bearing Abtnebsseitigen bearing plate. Preferably, the output-side rotor bearing is designed as a roller-floating bearing. It has proven to be advantageous if the brushless electric motor has a sensor board accommodated in the sensor receptacle for detecting the rotary position of the rotor shaft. Preferably, the sensor board between the non-driven end shield and the abtnebsseitigen bearing plate is arranged.

It has also proved to be advantageous if the sensor board is arranged between an underside of the bearing plate and the stator lamination stack. Under a bottom of the bearing plate should be understood to be the side of the bearing plate, which faces the output side bearing plate in normal operation.

An arrangement of the sensor board between the non-output end shield and the output-side end shield has the advantage that a shorter overall length of the brushless electric motor can be achieved. Preferably, a recess is provided on the non-output side end shield for this purpose in which the sensor board and / or the sensor ring magnet is received or can be added.

As an alternative to an arrangement of the sensor board between the non-output side end shield and the output side end shield, the sensor board may be arranged on a side facing away from the output side end shield of the non-output side end shield. Similarly, the sensor ring may be arranged on the side facing away from the output side end shield of the non-output side bearing plate.

In this regard, it has been recognized that the sensor board or the sensor ring is shielded by an unwanted interference magnetic field of a coil winding of the stator. This leads to an improved measured value of preferably provided Hall sensors on the sensor board, which ultimately further improves the commutation of the brushless electric motor.

In a further preferred refinement, the brushless electric motor has a fan arranged on the output side.

Further advantages will become apparent from the following description of the figures. In the figures, various embodiments of the present invention are shown. The figures, the description and the claims contain numerous features in combination. The person skilled in the art will expediently also consider the features individually and combine them into meaningful further combinations.

In the figures, identical and similar components are numbered with the same reference numerals.

Show it:

Figure 1 shows a preferred embodiment of a brushless electric motor in perspective view; Figure 2 shows a preferred embodiment of a non-output side bearing plate according to the invention in perspective view;

Figure 3 shows the brushless electric motor of Figure 1 in a sectional view;

FIG. 4 shows the non-output-side bearing plate of FIG. 2 arranged on a laminated stator core of a brushless electric motor (cf. FIG. 1); Figure 5 is a further sectional view through the brushless electric motor of Figure 1; and

FIG. 6 a stator laminated core of the brushless electric motor of FIG. 1 in perspective view.

EXAMPLES

FIG. 1 shows a preferred exemplary embodiment of a brushless electric motor 500 according to the invention. The brushless electric motor 500 has a laminated stator core 530, an output-side end shield 200 and a centrally arranged rotor shaft 560. Also provided on the brushless electric motor 500 of FIG. 1 is a fan 570 arranged on the output side.

Since FIG. 1 shows an operationally mounted brushless electric motor 500, the non-output side end shield 100 is not shown in its entirety. A more detailed explanation of the non-output bearing plate 100 follows with reference to Figure 2. From Figure 1, in turn, it is apparent that a sensor board 550 is on the output side bearing plate 200 facing away from the non-output side bearing plate 100 is added. The sensor board 550 serves for the rotational position detection of the rotor shaft 560.

The non-output side bearing plate 100 has three equally spaced retaining elements 127, each forming a riot for a clamping screw 527. By means of the clamping screws 527, the non-output side bearing plate 100 and the output-side end plate 200 are interconnected.

Already indicated in FIG. 1 is one of the three insertion elements 120 which will be described below with reference to FIG.

FIG. 2 shows a preferred exemplary embodiment of a non-output-side bearing plate 100 according to the invention. The non-output-side bearing plate 100 has a sensor receptacle 150, which serves as a carrier for a sensor board 550 (see FIG. 1). The non-output side end shield 100 and the sensor receptacle 150 are formed together as a one-piece component. In the illustrated embodiment, the non-output side bearing plate 100 is milled from a metal block. As can be seen from FIG. 2, the non-driven bearing plate 100 has exactly three plug-in elements 120 spaced apart from one another. The three equally spaced insertion elements 120 are for at least partially recording in each insertion member 120 corresponding insertion openings 530 (see Figure 6), which are formed in a laminated stator core 530 formed. The non-output side bearing plate 100 of Figure 2 has a variety of constructive surfaces with the exact positioning and alignment is facilitated. These areas will be described in more detail below.

First, each of the insertion elements 120 has a series of radially oriented and in the present plane centering surface 121, which is provided for concentric centering of the insertion element 120 with respect to the laminated stator core 530 (see FIG. 6). In the installed state, each of the planar centering surfaces 121 bears against a corresponding radial support surface 521 of the stator lamination stack 530 (see FIG. 6).

Furthermore, each of the insertion elements 120 has two tangentially oriented and in the present plan plan centering surfaces 123. The plane centering surfaces 123 serve for the angular orientation of the insertion element 120 with respect to the stator lamination stack 530. In the installed state (compare FIG. 5), the planar centering surfaces 123 abut against a respective tangential support surface 523 of the stator lamination stack 530.

Finally, each of the push-in elements 120 has an axially oriented and in the present plane-shaped bearing surface 125, which is provided for maintaining a defined axial position between the non-driven end shield 100 with respect to the stator lamination 530. As can already be seen from FIG. 1, the plane bearing surface 125 bears against a planar axial support surface 525 of the stator lamination stack 530.

FIG. 3 shows a longitudinal section through the brushless electric motor 500 of FIG. 1. As can be seen from FIG. 3, the non-driven end shield 100 has a sensor receptacle 150 which serves as a support for the sensor board 550 for detecting the rotation of the rotor shaft 560. The non-output-side bearing plate 100 and the sensor receptacle 150 are formed together as a one-piece component, which is presently recognizable by the hatching. Particularly clearly visible in FIG. 3 is a plane-shaped and radially oriented centering surface 121 of the insertion element 120, which is provided for the concentric centering of the insertion element 120 with respect to the stator lamination stack 530. In the installed state shown in FIG. 3, the planar and radially oriented centering surface 121 is supported on a radial support surface 521 of the stator lamination stack 530. In the present embodiment, the sensor board 550 is a carrier Hall sensor 555, which cooperates with a sensor ring 557 for the purpose of rotational position detection of the rotor shaft 560.

As can likewise be seen from FIG. 3, the sensor circuit board 550 can be arranged on a side of the non-output side end shield 100 facing away from the output-side end shield 200. This allows some shielding of the Hall sensor 555 from a magnetic field effect of the stator coil windings 590.

The rotor shaft 560 of the brushless electric motor 500 of FIG. 3 is mounted within the non-driven side bearing plate 100 in a non-driven side roller bearing 510 designed as a roller fixed bearing. On the output side, the rotor shaft 560 is mounted in a driven-side rotor bearing 580, wherein the output-side rotor bearing 580 is designed as a roller-floating bearing.

Figure 4 shows the release side bearing plate 100 in the installed state, that is arranged on a laminated stator core 530. Good to see here is the one-piece design of the non-output bearing plate 100 with the sensor receptacle 150 and the exactly three equally spaced insertion elements 120. Also clearly visible in that, in the installed state, the insertion elements 120 are accommodated at least in sections in a corresponding insertion opening 520 which is formed in the stator lamination stack 530.

Figure 5 shows a section across the electric motor 500 to illustrate the centering of the non-output side bearing plate 100 in the stator lamination 530. Good to see the three equally spaced insertion elements 120, which is clearly visible through the sectional view, within a volume of the stator lamination 530 extend , The radially oriented centering surfaces 121 are supported on a respective radial support surface 521 of the stator lamination stack 530. The tangentially oriented planar centering surfaces 123 which are provided on both sides of the insertion element 120 and serve for angular alignment abut against respective tangential support surfaces 523 of the stator lamination stack. In the three openings of the laminated stator core 530 in which no push-in element 120 is located, a respective pole tooth 540 of the electric motor 500 is shown. Finally, FIG. 6 shows the stator lamination stack 530 in a perspective view. Good to are the exactly three equally spaced apart corresponding insertion openings into which the insertion elements 120 (see Figure 2) are to be introduced.

In the presently illustrated embodiment, the laminated stator core has exactly six stator coil windings 590 which are equally spaced from each other along an inner circumference of the laminated stator core 530. Between two adjacent stator coil windings 590, three uniformly spaced radial support surfaces 521 are formed in the laminated stator core 530.

As can be seen from FIG. 6, these are formed as radial depressions within the stator lamination stack 530. Overall, exactly three radial support surfaces 521 are provided.

In the embodiment of Figure 6 exactly six tangential support surfaces 523 are also formed. These are disposed on a respective portion of the laminated stator core 530 which confines the stator coil winding 590 inwardly. Two adjacent tangential support surfaces 523 are each assigned to one of the insertion elements 120 (cf. FIG. 2). Finally, the planar axial support surface 525 can be seen on the outer circumference of the stator lamination stack 530, which acts as an uprising for the planar support surface 125 of the insertion elements 120 (see FIG. 2). The axial support surface 525 is formed by a planar end of the stator lamination 530.

LIST OF REFERENCE NUMBERS

100 non-output side bearing plate

1 10 bearing seat

120 insertion element

121 radially oriented centering surface

123 tangentially oriented centering surface

125 axially oriented bearing surface

127 holding elements

150 sensor recording

200 output side bearing plate

500 electric motor

510 non-driven rotor bearing

520 corresponding insertion opening

521 radial support surface

523 tantalum support surface

525 axial support surface

527 clamping screw

530 stator core

540 Pohlzahn

550 sensor board

555 Hall sensor

557 Sensor ring

560 rotor shaft

570 fans

580 driven rotor bearing

590 stator coil winding

US underside of bearing plate

Claims

claims

Non-output bearing plate (100) for a brushless electric motor (500), with a centrally disposed bearing seat (1 10) for receiving a non-driven rotor bearing (510) for a rotor shaft (560) of the brushless electric motor (500), characterized in that the non-output side bearing plate (100) has a sensor receptacle (150), which serves as a support for a sensor board (550) for rotational position detection of the rotor shaft (560), wherein the non-output bearing plate (100) and the sensor receptacle (150) are formed together as a one-piece component.

Non-driven end shield (100) according to claim 1,

characterized in that the non-output bearing plate (100) has three equally spaced insertion elements (120) for at least partially receiving in a respective insertion element (120) corresponding insertion opening (520), the stator core (530) of the electric motor (500) is associated, are formed.

Non-driven end shield (100) according to claim 2,

characterized in that each of the insertion elements (120) has a radially oriented and preferably planar centering surface (121) which is provided for concentric centering of the insertion element (120) with respect to the stator lamination stack (530) and in the installed state on a radial support surface (521) of the stator lamination stack (530) is present.

Non-driven end shield (100) according to one of claims 2 or 3,

characterized in that each of the push-in elements (120) has two tangentially oriented and preferably plane centering surfaces (123) which are provided for angular alignment of the push-in element (120) with respect to the stator lamination stack (530) and in the installed state at a respective tangential support surface (523) of the stator lamination stack (530) is present.

Non-driven end shield (100) according to one of claims 2 to 4,

characterized in that each of the push - in elements (120) has an axially oriented and preferably planar bearing surface (125) which is adapted to maintain a defined axial position between the non - driven end shield (100) with respect to Statorblechpakets (530) is provided and in the installed state of a preferably flat Axialstützfläche (525) of the stator lamination stack (530) is applied.

Non-output bearing plate (100) according to any one of the preceding claims, characterized in that the non-output side bearing plate (100) has three equally spaced holding elements (127), each having a riot for a clamping screw (527) for connecting the non-output side bearing plate (100 ) is provided with a driven-side end shield (200).

Non-driven end shield (100) according to any one of the preceding claims, characterized in that non-driven rotor bearing (510) is designed as a roller fixed bearing.

A brushless electric motor (500) comprising a laminated stator core (530), an output side end shield (200), a non-output side end shield (100) according to any one of the preceding claims and a rotor shaft (560) mounted in a driven side rotor bearing (580) of the output side end shield (200) ), wherein the output-side rotor bearing (580) is designed as a roller-floating bearing.

Brushless electric motor (500) according to claim 8,

characterized in that the brushless electric motor (500) in the sensor receptacle (150) recorded sensor board (550) for rotational position detection of the rotor shaft (560), wherein the sensor board (550) between the non-output bearing plate (100) and the output-side end shield (200 ) is arranged, preferably between a bottom (US) of the bearing plate (100) and the stator lamination stack (530).

Brushless electric motor (500) according to claim 8 or 9,

characterized in that the brushless electric motor (500) has a driven side arranged fan (570).