Brushless motor, braking device and method for manufacturing a brushless motor

Abstract

The invention relates to an electronically commutated electric machine, a braking device and a method for producing an electronically commutated electric machine, in particular an electronically commutated motor, having a rotor (14) which is arranged on a rotor shaft (16) which can be set in rotary motion. In order to detect the angle of rotation of the rotor shaft (16), a signal transmitter (24) is provided which comprises a holding element (28) and a magnetic element (26) which is arranged at the holding element. A clamping body (40) is proposed for fixing the holding element (28) at the rotor shaft (16), which is configured with at least one fixing portion (50, 52) which, in the assembled state, acts on the magnetic element (26) and prevents a translational movement and a rotational movement of the magnetic element (26) relative to the holding element (28). The proposed solution is designed to eliminate the known adhesive connection between the magnetic element (26) and the holding element (28).

Description

Technical Field

[0001] The present invention relates to an electronically commutated motor according to the present invention, a braking device with electronically anti-slip control having an electronically commutated motor according to the present invention, and a method for manufacturing an electronically commutated motor according to the present invention. Background Technology

[0002] Electronically commutated motors are used as drive assemblies, for example, in electronically controlled anti-slip braking systems of motor vehicles, to drive a pressure generator in the event of brake pressure regulation. Here, the motor is electrically controlled by the electronic controller of the braking system as needed. In the case of electrical control, the pressure generator delivers a pressure medium within the braking circuit. Therefore, braking pressure is established in the connected wheel brakes in proportion to the volume of the delivered pressure medium. By means of an additional valve device controllable by the electronic controller, the braking pressure can be matched to the slip condition present at the corresponding wheel on each wheel. This prevents wheel lock-up during braking and thus improves vehicle stability. Furthermore, the braking process can be performed independently of the driver, depending on the current traffic or driving conditions.

[0003] During this regulation process, the volume of the pressure medium squeezed into the braking circuit by the pressure generator is a key control parameter. It can be determined by the operating parameters of the drive assembly. For this purpose, there are sensor devices that detect the rotation angle and / or speed of the rotor of the drive assembly and transmit the measured signals to the electronic controller for subsequent calculation and evaluation.

[0004] Known sensor devices consist of a signal transmitter that rotates with the rotor shaft and a signal receiver that is fixed in position. The signal transmitter includes at least one magnetic element, which is fixed to the rotor shaft of the drive assembly in a non-rotational manner by means of a retaining element.

[0005] The electronically commutated motor according to the invention is prior art and is disclosed, for example, in DE 10 2017 218 648 A1. This known motor is a drive assembly for a pressure generator in a vehicle braking device with electronic anti-skid control, as described in that document. Figure 1 The image is shown in a side view.

[0006] The known drive assembly 10 includes an electronically commutated electric motor 12, which has a rotor 14 that can be driven to rotate and a rotor shaft 16 that is non-rotatably connected to the rotor 14. The rotor 14 has a conventional structure and has an iron core and a plurality of permanent magnets arranged one after another along the circumferential direction of the iron core.

[0007] The magnetic field of the permanent magnet interacts with the magnetic field of the stator's coils in a known manner. For this purpose, the stator includes a housing 18 on which coils are mounted on its inner surface opposite the permanent magnet. Due to the interaction between the magnetic fields, the rotor 14 and the rotor shaft 16 perform a common rotational motion.

[0008] The rotor shaft 16 is exemplarily rotatably supported in the housing 18 of the drive assembly 10 by means of rolling bearings 20. Figure 1 A plurality of eccentric elements 22 are exemplary arranged on the rotor shaft 16 to operate a device, not shown, such as a piston pump, which is arranged transversely to the longitudinal axis L of the rotor shaft 16.

[0009] according to Figure 1 Detail II shows the signal transmitter 24 of the sensor device for electronically detecting and evaluating the rotational angle and / or rotational speed of the rotor 14 or rotor shaft 16. The signal transmitter 24 is arranged at the end of the rotor shaft 16 opposite to the rotor 14. The signal transmitter has a magnetic element 26, which is indirectly fixed to the rotor shaft 16 by a retaining element 28. The retaining element 28 is cup-shaped and has a protruding mandrel 30 through which the retaining element is press-fitted into and bonded to an associated central hole 32 of the rotor shaft 16 (the bonded connection is not visible). A blind-hole-shaped, outwardly open receiving portion 34 is constructed on the side of the retaining element 28 opposite to the mandrel 30, in which the magnetic element 26 is mounted flush with the outside. The magnetic element 26 is also fixed in the receiving portion 34 of the retaining element 28 by an invisible bonded connection.

[0010] Under the operating conditions of the drive assembly, rotor 14 typically accelerates or decelerates rapidly. Here, the bonded joint is subjected to high dynamic loads and is therefore prone to failure. Due to the bonded joint, the magnetic element fixed to the retaining element is subject to a certain degree of elasticity, resulting in relatively large measurement tolerances when detecting sensor positions or rotation angles. Furthermore, in mass production, the bonded joint requires significant expenditure on maintenance-intensive equipment, such as for dispensing and curing the adhesive. The necessary retaining element and the center hole at the rotor shaft incur additional costs. Summary of the Invention

[0011] In contrast, the electronically commutated motor according to the invention has the advantage that the magnetic elements are now fixed to the rotor shaft by force transmission or form fit, rather than by material fit, thus providing better rigidity than in the prior art. Therefore, the detection of the rotation angle signal or rotor speed is more accurate, which ultimately improves the electrical controllability of the motor and thus reduces possible deviations between the actual volume of the pressure medium being delivered and the desired theoretical value, or between the set braking pressure and the theoretical braking pressure. Furthermore, the manufacturing process of the motor is shortened because the necessary preparation of the bonding areas or the waiting time for the adhesive material to harden is eliminated. Measuring devices for the adhesive material or, if necessary, ultraviolet radiation devices for the hardening of the adhesive material are eliminated. Moreover, the force transmission / form fit fixing process can be more easily monitored in terms of process technology.

[0012] A method is proposed to fix a retaining element for a magnetic component to the rotor shaft by means of a clamping body, wherein the clamping body is provided with a fixing part for the magnetic component.

[0013] Suitable clamping bodies include, for example, tolerance rings made of spring steel, further improved in such a way that they are located in the gap between the inner contour of the retaining element and the outer contour of the rotor shaft. Such tolerance rings enable the use of rotor shafts with a more cost-effective, continuously constant shaft diameter. Because the presence of the clamping body increases the radial dimension of the retaining element, it provides more mounting space for the magnetic element. Correspondingly larger magnetic elements, protruding beyond the cross-section of the rotor shaft, provide a stronger and more uniform magnetic field, which can be more easily detected and evaluated by the signal receiver. Therefore, the rotational angle or speed traversed by the rotor shaft can be determined with greater accuracy, or a more cost-effective signal receiver and a magnetic element with larger tolerances can be used. The latter, in turn, simplifies the interchangeability of components such as controllers and motors.

[0014] Other advantages and beneficial improvements of the invention will become apparent from the following description.

[0015] According to the invention, the clamping body has a fixing portion. A first fixing portion acts on the end side of the magnetic element, and causes the magnetic element to abut against the bottom of a cup-shaped retaining element, which is now more simply designed, by axial preload. A second fixing portion abuts the magnetic element, for example, at a flattened portion of the magnetic element, or engages in a recess open towards the end side of the magnetic element, thus fixing the magnetic element to the retaining element without relative rotation. The fixing portions are cost-effectively constructed in one piece, preferably only on the side of the clamping body facing the magnetic element, and are correspondingly distributed along the circumference of the clamping body. The fixing portions extend along the longitudinal or radial direction of the clamping body, and can be simply presented, for example, by a corresponding deformation of a tongue-like portion that can be constructed at the clamping body. The number, shape, arrangement, or positioning of the fixing portions at the clamping body can be selected as needed. The clamping body has a sleeve shape, at least in the assembled state. The sleeve can be implemented with slots on the circumferential side, and can therefore be simply and cost-effectively made, for example, by punching and stamping strip sheet. Attached Figure Description

[0016] Embodiments of the invention are illustrated in the accompanying drawings, and are described in detail in the following description.

[0017] The accompanying drawings consist of two figures in total, with corresponding parts always labeled with the same reference numerals.

[0018] Figure 1 The main components of an electronically commutated motor, known from the prior art and described in the introduction of the specification, are shown in longitudinal sectional view.

[0019] Figure 2 The 3D illustration shows the design scheme according to the present invention. Figure 1 Details II.

[0020] Figure 3 This is a top view of the solution according to the invention when the retaining element is removed. Detailed Implementation

[0021] Figure 2 The end of the rotor shaft 16 of the electronically commutated motor equipped with a signal transmitter 24 is shown. This end is opposite a second end (not marked) on which the motor rotor is mounted. See [reference needed]. Figure 1 The rotor shaft 16 always has a constant outer diameter and is cut perpendicular to the longitudinal axis L, thus having a shaft end side oriented perpendicular to the longitudinal axis L. The transition from the shaft end side to the shaft periphery is constructed as a chamfered bevel, but it can also be implemented alternatively with rounded corners.

[0022] A clamping body 40 in the shape of a tolerance ring is provided at the shown end of the rotor shaft 16. The clamping body 40 is implemented as a cylindrical sleeve, which can be configured to be closed on the circumferential side or slotted on the circumferential side. The slotted sleeve can be more cost-effectively made by bending a strip of sheet metal.

[0023] Viewed along the longitudinal axis L of the rotor shaft 16, the clamping body 40 is divided into a first clamping body section 40a on the rotor side, which abuts flush with the outer periphery of the rotor shaft 16 under an adjustable radial preload. The first clamping body section 40a transitions into an intermediate section 40b, where an extension 42 is formed, protruding radially outward from the clamping body 40. In this embodiment, a plurality of such extensions 42 are arranged one after another at regular intervals along the entire periphery of the clamping body 40. For example, the extensions are designed identically to each other and are oriented parallel to each other. The extension 42 has a trapezoidal cross-section with a base that is largely flat, physically connected to the rest of the clamping body by a surrounding ramp. The extension 42 extends primarily along the longitudinal axis L of the rotor shaft 16 or the clamping ring 40. An air chamber is formed between the corresponding protrusion 42 and the outer periphery of the rotor shaft 16, through which the protrusion 42 imparts elasticity to the clamping body 40 in the radial direction.

[0024] Connected to the intermediate section 40b of the clamping body 40 is the end section 40c, which is further divided into multiple axial regions along the longitudinal axis L. A first axial region 44, arranged adjacent to the intermediate section, is flush with the periphery of the rotor shaft 16 under selectable radial preload, while a second axial region 46, moving away from the intermediate region, extends beyond the end of the rotor shaft 16. The end section 40c generally has approximately the length of the intermediate section 40b of the clamping body 40, and is configured to be longer than the first axial region 44 when viewed along the longitudinal axis L of the rotor shaft 16. A fixing portion is integrally constructed with the clamping body 40 at the second axial region 46 extending beyond the rotor shaft 16. The fixing portion is a tongue-shaped protrusion of the clamping body 40. A first fixing portion 50 extends inward at a right angle, or protrudes inward radially from the periphery of the clamping body 40, while a second fixing portion 52 is oriented axially parallel to the longitudinal axis L. In the assembled state shown for the signal transmitter 24, there is an axial distance or gap between the inwardly pointing first fixing part 50 and the end side of the rotor shaft 16 in the direction of the longitudinal axis L. The first fixing part 50 and the second fixing part 52 are arranged one after another along the periphery of the clamping body 50 in a plurality of numbers that can be determined according to the specific application. Here, the alternating arrangement of the fixing parts is not mandatory. The radially inwardly pointing first fixing part 50 can be made, for example, by simply flipping over the tongue-shaped protrusions along the circumference of the clamping body 40.

[0025] The function of the fixing part is to fix the magnetic element 26 of the signal transmitter 24 in the cup-shaped retaining element 28 by force transmission or shape matching, so that the magnetic element 26 cannot be translated in the axial direction or rotated in the circumferential direction relative to the retaining element 28, and this fixes the magnetic element 26 without the need for material matching.

[0026] For this purpose, the magnetic element 26 is designed to be substantially cylindrical and has an end side oriented perpendicular to the longitudinal axis L and parallel to a plane. A first fixing portion 50 of the clamping body 40 acts on the end side facing the rotor shaft 16, and the first fixing portion 50 causes the magnetic element 26, with its end side opposite to the end side facing the rotor shaft 16, to be pressed against the bottom 54 of the cup-shaped retaining element 28 by an adjustable axial preload. A pair of flat locking surfaces 56, facing each other, are constructed around the periphery of the magnetic element 26, and a second fixing portion 52 of the clamping body 40 acts on these locking surfaces 56, thereby preventing the magnetic element 26 from potentially rotating relative to the retaining element 28. Instead of the locking surfaces 56, the magnetic element 26 may also have, for example, an axially oriented recess into which the second fixing portion 52 engages.

[0027] As described above, the retaining element 28 is cup-shaped and has a cylindrical portion 58 and a bottom 54 at the end of the cylindrical portion 58. The inner diameter of the retaining element 28 matches the outer diameter of the clamping body 40 in the region of the protrusion 42, such that when the retaining element 28 moves onto the clamping body 40, a radial force is established between the retaining element 28 and the clamping body 40 on the one hand, and between the clamping body 40 and the rotor shaft 16 on the other hand. This radial force axially and non-rotatably fixes the retaining element 28 to the clamping body 40, and simultaneously axially and non-rotatably fixes the clamping body 40 to the rotor shaft 16. This effective radial force can be structurally adjusted by coordinating the internal or external dimensions of the retaining element 28, the clamping body 40, and the rotor shaft 16. In the final assembled state of the signal transmitter 24, the cylindrical portion 58 of the retaining element 58 covers the clamping body 40 on the circumferential side. The bottom 54 can cover the entire cross-section of the retaining element 58, and thus prevent damage and / or contamination of the magnetic element 26 arranged inside the retaining element 28, or provide an opening at the bottom 54 if necessary. The cup-shaped retaining element 28, in particular, is made of a non-ferromagnetic material, like the clamping body 40, so as not to weaken or affect the magnetic field of the magnetic element 26.

[0028] Figure 3A top view of the signal transmitter 24 with the retaining element 28 removed is shown. A generally cylindrical magnetic element 26 can be seen, having flat locking surfaces 56 facing each other. A second fixing portion 52 fits into the locking surface 56 and prevents the magnetic element 26 from rotating about a longitudinal axis L, which extends perpendicularly to the drawing plane and can therefore be considered only as the intersection of the center lines passing through the magnetic element 26. Because it is obscured by the magnetic element 26, a first fixing portion 50 is drawn in dashed lines. This first fixing portion is located on the invisible lower end side of the magnetic element 26 and presses the magnetic element 26 upwards in the drawing plane, thereby axially fixing the magnetic element 26 in place. Figure 3 The retaining element 28 is removed from the interior. A total of four first fixing parts 50 and two second fixing parts 52 are shown, wherein the number of fixing parts and the relative arrangement of the fixing parts shown are to be understood as exemplary and not limiting.

[0029] Various methods can be devised to mount the signal transmitter 24 onto the rotor shaft 16.

[0030] The first method specifies that the clamping body 40 is first pushed axially onto the rotor shaft 16 until it is almost at its final position. Then, the magnetic element 26 is placed on the clamping body 40 by means of the fixing part of the clamping body 40, and finally, the cup-shaped retaining element 28 is pushed onto the assembly consisting of the clamping body 40 and the magnetic element 26. Now, the retaining element 28, together with the clamping body 40 and the magnetic element 26, is press-fitted onto the rotor shaft 16 according to standard, thereby adjusting the final position of the signal transmitter 24 on the rotor shaft 16.

[0031] The alternative second method specifies that the signal transmitter 24 is first placed, and then the pre-assembled signal transmitter 24 is fixed to the rotor shaft 16. For this purpose, the magnetic element 26 is first placed at the clamping body 40, and then this assembly is installed into the retaining element 28 of the signal transmitter 24 with the magnetic element 26 stopped at the bottom 54. Next, the signal transmitter 24 is press-fitted onto the rotor shaft 16 as a structural unit until the signal transmitter occupies its final position.

[0032] Of course, variations or additions beyond the scope of this disclosure may be conceived without departing from the basic idea of ​​the invention as set forth. This basic idea, in particular, involves arranging the signal transmitter 24 on the rotor shaft 16 in a non-rotatable and axially fixed manner through force transmission and / or form fitting, thereby eliminating the need for costly adhesive connections.

Claims

1. An electronically commutated electric motor (10) having a rotor (14) on a rotor shaft (16) which can be set in rotary motion and a signal transmitter (24) comprising a holding element (28) fixed non-rotatably on the rotor shaft (16) and a magnetic element (26) arranged at the holding element (28) for detecting the angle of rotation of the rotor (14) and / or the rotor shaft (16), characterized in that the holding element (28) is fixed on the rotor shaft (16) by means of a clamping body (40) which is placed between the inner diameter of the holding element (28) and the outer diameter of the rotor shaft (16) and in that the clamping body (40) has at least one fixing portion acting on the magnetic element (26) which prevents a translational and rotational movement of the magnetic element (26) relative to the holding element (28) in the assembled state of the signal transmitter (24), wherein a protrusion (42) is formed at a middle section (40b) of the clamping body (40) which protrudes radially outwardly from the clamping body (40) such that an air chamber is enclosed between the respective protrusion (42) and the outer circumference of the rotor shaft (16), and wherein the inner diameter of the holding element (28) matches the outer diameter of the clamping body (40) in the region of the protrusion (42). The holding element (28) is configured in the shape of a cup and the magnetic element (26) is accommodated in the interior of the holding element and a first fixing portion (50) presses the magnetic element (26) against the bottom (54) of the holding element (28). The first fixing portion (50) is oriented transversely to the longitudinal axis (L) of the clamping body (40) and lies against an end side of the magnetic element (26) facing the rotor shaft (16). The magnetic element (26) is pressed in axial pretension against the bottom (54) of the holding element (28) by means of the first fixing portion (50). The magnetic element (26) is pressed in axial pretension against the bottom (54) of the holding element (28) by means of the first fixing portion (50).

2. The electronically commutated electric motor (10) of claim 1, characterized by At least one second fixing portion (52) is provided which acts jointly in the case of a form-fitting connection with the magnetic element (26).

3. The electronically commutated electric motor (10) of claim 2, characterized by The second fixing portion (52) extends axially parallel to the longitudinal axis (L) of the clamping body (40) and lies against at least one assigned locking surface (56) at the circumference of the magnetic element (26).

4. The electronically commutated electric motor (10) of claim 2, characterized by The first fixing portion (50) and the second fixing portion (52) are respectively configured integrally with the clamping body (40) and are arranged along the circumference of the clamping body (40).

5. The electronically commutated electric motor (10) of claim 3, characterized by The first fixing portion (50) and the second fixing portion (52) are respectively configured integrally with the clamping body (40) and are arranged along the circumference of the clamping body (40).

6. The electronically commutated electric motor (10) according to any one of claims 2 to 5, characterized in that ​ 7. The electronically commutated electric motor (10) of claim 6, characterized by ​ 8. The electronically commutated electric motor (10) as claimed in claim 6, characterized by ​ 9. The electronically commutated electric motor (10) as claimed in claim 7, characterized in that ​ 10. The electronically commutated electric motor (10) according to any one of claims 1 to 5, characterized in that The fixing portion is configured on a side of the clamping body (40) facing the magnetic element (26).

11. The electronically commutated electric motor (10) according to any one of claims 1 to 5, characterized in that The magnetic element (26) can be arranged axially fixed and rotationally fixed relative to the holding element (28) by means of the fixing portion.

12. The electronically commutated electric motor (10) according to any one of claims 1 to 5, characterized in that The electronically commutated motor (10) is an electronically commutated motor.

13. An electronically controllable brake device, having a pressure generator and an electronically commutated motor (10) according to the features of any one of claims 1 to 12 for driving the pressure generator.

14. An electronically controllable brake device according to claim 13, characterised in that The electronically controllable brake device is used in a motor vehicle.

15. A method for producing an electronically commutated motor (10) having a rotor (14) on a rotor shaft (16) that can be set in motion in rotation and a signal transmitter (24) comprising a holding element (28) fixed rotationally fixed on the rotor shaft (16) and a magnetic element (26) fixed on the holding element (28) for detecting the angle of rotation of the rotor (14) and / or the rotor shaft (16), characterized in that a clamping body (40) provided with a fixing portion is placed on the rotor shaft (16), the magnetic element (26) of the signal transmitter (24) is arranged at the clamping body (40) by means of the fixing portion, and the cup-shaped holding element (28) of the signal transmitter (24) is press-fitted onto the clamping body (40) with the magnetic element (26), wherein a protrusion (42) is formed at the middle section (40b) of the clamping body (40), which protrudes radially outward from the clamping body (40) such that an air chamber is formed between the respective protrusion (42) and the outer circumference of the rotor shaft (16), and wherein the inner diameter of the holding element (28) matches the outer diameter of the clamping body (40) in the region of the protrusion (42).

16. The method of claim 15, wherein, The electronically commutated motor (10) is an electronically commutated motor.

17. A method for producing an electronically commutated motor (10) having a rotor (14) on a rotor shaft (16) that can be set in motion in rotation and a signal transmitter (24) comprising a holding element (28) fixed rotationally fixed on the rotor shaft (16) and a magnetic element (26) arranged at the holding element (28) for detecting the angle of rotation of the rotor (14) and / or the rotor shaft (16), characterized in that the magnetic element (26) of the signal transmitter (24) is first arranged at the clamping body (40) by means of a fixing portion of the clamping body (40), then a structural unit comprising the clamping body (40) and the magnetic element (26) is placed inside the cup-shaped holding element (28) of the signal transmitter (24), and the cup-shaped holding element (28) of the signal transmitter (24) is press-fitted onto the clamping body (40) with the magnetic element (26), wherein a protrusion (42) is formed at the middle section (40b) of the clamping body (40), which protrudes radially outward from the clamping body (40) such that an air chamber is formed between the respective protrusion (42) and the outer circumference of the rotor shaft (16), and wherein the inner diameter of the holding element (28) matches the outer diameter of the clamping body (40) in the region of the protrusion (42). The electronically commutated motor (10) is an electronically commutated motor. The holding element (28) with the magnetic element (26) and the clamping body (40) is then press-fitted onto the end of the rotor shaft (16), wherein at the intermediate section (40b) of the clamping body (40) a protrusion (42) is formed which projects radially outward from the clamping body (40) such that an air chamber is enclosed between the respective protrusion (42) and the outer circumference of the rotor shaft (16), and wherein the inner diameter of the holding element (28) matches the outer diameter of the clamping body (40) in the region of the protrusion (42).

18. The method of claim 17, wherein, The electronically commutated electric machine (10) is an electronically commutated motor.

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