Brush system for electric motor

Abstract

The invention relates to a brush system (54) for an electric motor (15), comprising a brush holder (56), which has at least one brush cartridge (82) for movably supporting a brush (52), which is arranged around a central shaft opening (66) through which a motor shaft (28) can pass, wherein the brush holder (56) has an integrally formed sliding bearing (44) for the sliding bearing of the motor shaft (28) in the region of the shaft hole (66).

Description

[0001] This invention relates to a brush system for an electric motor, the brush system having a brush holder having at least one brush barrel for movably supporting brushes arranged around a central shaft hole through which a motor shaft can pass. The invention also relates to an electric motor including a brush system, an adjustment driver including such an electric motor, and an automotive window regulator including such an adjustment driver.

[0002] Today, automobiles are typically equipped with a number of adjustable components, such as seat adjusters, operable locks, power windows, and / or adjustable sunroofs. These components can be moved between different preset positions by means of their respective electric adjustment actuators. The corresponding adjusting components are operated by a transmission mechanism (in the form of a worm gear drive, for example) driven by a DC motor or electric motor. This transmission mechanism has a worm gear on the motor shaft (drive side) and a worm wheel on the output side. The transmission mechanism is usually housed in a transmission housing, and the electric motor is flange-connected to the transmission housing via its motor housing.

[0003] Brushed motors or mechanically commutated motors are commonly used as electric motors. These motors, also known as commutator motors, consist of a stator and a rotor mounted on a motor shaft (rotor shaft). The rotor is driven by an alternating magnetic field within the stator. The rotor is equipped with excitation windings or drive windings, and the motor shaft has commutator segments fixed to the rotor. Sliding contacts in the form of brushes from the brush system brush across these commutator segments. As the motor shaft rotates, the brush system and commutator segments interact, thereby reversing the polarity or current direction (commutation) of the rotor windings (rotor windings, drive windings) and the operating current or motor current.

[0004] Electric brushes are typically cubic rod-shaped objects made of pressed carbon powder (sometimes mixed with metal particles). Due to sliding contact with the commutator segments, the brushes wear down during motor operation. To maintain contact between the brush and the commutator even under wear, spring elements are generally used to press the brush against the commutator, which is concentric with the motor shaft. During motor operation, direct current flows through the brushes and the commutator segments into the rotor's excitation windings.

[0005] Typically, the brush system is implemented as a pre-assembled (sub)component, which is installed into the driver housing during the installation of the regulating driver. The brush system usually has a carrier element (e.g., a carrier plate) as a so-called brush holder, on which the components of the brush system are pre-assembled. In other words, the brushes, brush holders, springs, contacts for plugs or other interfaces, as well as anti-interference components, sensors, and thermocouples, are all pre-assembled on the brush holder so that the entire brush system can be installed in place later when the regulating driver is installed. This means that the brush system is usually installed separately, i.e., separately from the regulating driver, and then sent to the regulating driver production line.

[0006] To drive and couple the motor shaft to the transmission, the brush system or brush holder has a shaft bore that serves as a through-hole for the motor shaft. A sliding bearing (sliding contact bearing) is typically provided within the shaft bore area for slidingly supporting the motor shaft. This sliding bearing is implemented as a separate component, pressed into a bearing housing within the brush holder or shaft bore during pre-assembly of the brush system.

[0007] When pressing a sliding bearing into the bearing housing, it is possible that the sliding bearing may not be fully or correctly pressed in, and / or the sliding bearing may tilt in the bearing housing or shaft bore. Furthermore, during the installation of the sliding bearing, tests and measurements are required to determine the minimum pressure at which the sliding bearing will not disengage from the brush system.

[0008] The purpose of this invention is to provide a brush system particularly suitable for electric motors. Specifically, it provides a reliable and simple sliding support scheme for the motor shaft to prevent installation errors. Another purpose of this invention is to provide a particularly suitable electric motor, a particularly suitable regulating driver, and a particularly suitable window regulator.

[0009] According to the invention, with respect to the brush system, this objective is achieved by the features of claim 1; with respect to the electric motor, this objective is achieved by the features of claim 6; with respect to the regulating actuator, this objective is achieved by the features of claim 8; and with respect to the window regulator, this objective is achieved by the features of claim 10. Advantageous designs and improvements are the subject of the dependent claims (sub-claims).

[0010] The advantages and design schemes mentioned regarding brush systems can also be similarly applied to electric motors and / or regulating drives and / or window regulators, and vice versa.

[0011] Here and in the following text, the word “and / or” should be understood as meaning that the features associated with the conjunction can coexist or serve as alternatives to each other.

[0012] The brush system according to the invention is used for electric motors, particularly for brush-commutated motors (commutator-type motors), and is adapted and configured for this purpose.

[0013] The brush system has a plate-shaped brush holder with a central shaft hole through which the motor shaft of the electric motor passes. Around the shaft hole, at least one brush holder is arranged to movably support a (carbon) brush. Specifically, at least two brush holders, each carrying one brush, are provided, for example, arranged diametrically opposite each other at the shaft hole. Each brush, for example, makes elastic electrical contact with the commutator located within the shaft hole in the installed state via a spring element, which applies a spring force to the brush when effectively connected to it, causing it to press against the commutator.

[0014] The brush holder contains, for example, electrical components connected to the brushes, particularly anti-interference elements such as chokes (anti-interference chokes). The brush holder also contains electrical contact points for supplying power to the brushes or commutator.

[0015] The brush holder also has a sliding bearing in the shaft hole area for slidingly supporting the motor shaft. According to the invention, the sliding bearing is integrally formed on the brush holder (i.e., one-piece or integral). That is, the sliding bearing is an integral part of the brush holder. In other words, the sliding bearing is integrated into the brush holder. This achieves a particularly suitable brush system.

[0016] The sliding bearing is formed, for example, by additional walls that surround or encircle the motor shaft as sliding surfaces. This eliminates the need for additional or separate sliding bearings, and in particular, eliminates the need for a press-fit process to (pre-)install the sliding bearing. Therefore, the brush system of the present invention is particularly inexpensive because it eliminates the need for additional sliding bearings, the press-fit process, and the associated testing and measurements. Furthermore, motor performance problems caused by poor orientation (parallelism) or positioning of the press-fit sliding bearing are essentially completely avoided.

[0017] The one-piece design of the sliding bearing also helps reduce the structural weight of the brush system. Furthermore, the one-piece sliding bearing reduces the carbon footprint (CO2 footprint) of the brush system manufacturing process.

[0018] The sliding bearing is used to support the (through) opening of the motor shaft, and its net width (opening diameter or inner diameter) is preferably designed so that the motor shaft is mounted in the sliding bearing with the smallest possible clearance.

[0019] In an advantageous improved design, the brush holder has a tubular or hollow cylindrical shaft guide that includes a shaft bore and a sliding bearing. The shaft guide is, for example, an integrally formed (support) sleeve on the brush holder, which essentially forms a (bearing) housing of the brush holder that accommodates the sliding bearing. In the installed state, the shaft guide, together with the motor shaft, engages, for example, in a corresponding receptacle within the transmission housing. This receptacle specifically stabilizes the shaft guide and the sliding bearing formed therein, thereby ensuring reliable and operational support for the motor shaft.

[0020] In a practical design, the brush holder is implemented as an injection-molded part. Preferably, the sliding bearing is manufactured directly in the injection mold of the brush holder. This allows the width of the formed sliding bearing to be adjusted very easily by using different sliders or inserts in the injection mold. This ensures a particularly simple, low-cost, and flexible manufacturing process.

[0021] In a preferred design, the sliding bearing has a sliding ring that supports the motor shaft. In this case, the sliding ring surrounds the motor shaft, with the inner ring wall forming the sliding bearing surface. The sliding ring is connected to the brush holder or shaft guide by a number of radial struts (e.g., four struts). This ensures that the sliding ring is stable and can be fixed in place for operation.

[0022] An additional or other aspect of the invention proposes that a pouch-like portion is formed between every two adjacent support rods. The pouch-like portion refers to a closed (radial) wall between two support rods, the thickness of which is smaller than that of the support rods. During injection molding, the pouch-like portion ensures uniform wall thickness and mass of the support rods or sliding bearings during melt flow.

[0023] The electric motor of the present invention is used in the regulating drive of automobiles, particularly in the drive mechanism of window regulators, and is adapted and configured for this purpose. The motor is designed as a commutator-type motor and has a cup-shaped motor housing or pole cups, in which the stator, the rotor fixed to the motor shaft, and the commutator are housed. The commutator is swept across by the aforementioned brush system. This results in a particularly suitable motor in which the motor shaft is reliably, cost-effectively, and with guaranteed operation is ensured by integrated sliding bearings.

[0024] In one conceivable design, the motor housing has a housing opening on one side for the motor shaft. This opening is then closed by a brush system or brush holder. In other words, the brush holder essentially completely covers the housing opening. Therefore, the brush holder essentially forms a housing cover or end cap for the motor housing. The shaft guide of the brush system extends outwards.

[0025] The adjustment actuator of the present invention is provided for automobiles and is suitable and configured for this purpose. In a preferred application, the adjustment actuator is designed as a window regulator drive, particularly for cable-operated window regulators. The adjustment actuator has a transmission housing internally housing the transmission components and the aforementioned electric motor. This achieves a particularly suitable adjustment actuator.

[0026] The electric motor or its housing is secured to the transmission housing by means of an end-face flange screw. The transmission component is driven by the motor shaft. The regulating drive, for example, has a worm gear transmission, wherein the transmission component is designed as a worm gear, and the motor shaft has a shaft-fixed worm that engages with the worm gear.

[0027] In one practical design, the motor brush holder is at least partially inserted into the drive housing, such that the sliding bearing is located inside the drive housing. This results in a particularly compact regulating drive.

[0028] The window regulator of the present invention is, for example, implemented as a cable-operated window regulator for a car side door. This window regulator includes the aforementioned adjustment actuator as a window regulator drive device. This results in a particularly suitable window regulator.

[0029] The embodiments of the present invention will now be described in detail with reference to the accompanying drawings. Wherein:

[0030] Figure 1 This is a schematic diagram of a car window regulator.

[0031] Figure 2 Perspective view of the partially disassembled electric adjustment actuator of the window regulator.

[0032] Figure 3 To adjust the partial cross-sectional view of the driver,

[0033] Figure 4 An external perspective view of the brush system for adjusting the driver.

[0034] Figure 5 Internal perspective view of the brush system

[0035] Figure 6 For the brush system along Figure 4 The cross-sectional view taken by section line VI-VI in the middle, and

[0036] Figure 7 For the brush system along Figure 4 A cross-sectional view taken from section line VII-VII.

[0037] In all drawings, corresponding parts and dimensions always use the same reference labels.

[0038] Figure 1 An electric cable-operated window regulator is shown in a simplified and schematic manner as a window regulator 2 for a vehicle window 4. This cable-operated window regulator 2 has an adjustment actuator (cable actuator) 6 that actuates the window 4 via an actuator 8 and a drive member 10. In the illustrated embodiment, the actuator 8 has a cable mechanism 12 for the drive member 10 and a guide rail 14.

[0039] The electric motor 15, acting as the electric actuator of the regulating drive 6, drives the rope drum 18 of the actuator 8 via a worm gear transmission or a spur gear transmission 16. The arrangement of the cable of the cable mechanism 12 on the rope drum 18 is such that when the transmission device 16 causes the rope drum 18 to rotate, the cable winds up and unwinds. For example, the cable mechanism 12, implemented as a Bowden cable, moves the window 4 via the (cable) guide pulley 20 on the guide rail 14.

[0040] When the actuator 6 is operated, the window glass 4 moves at its position P. The window glass 4 can reversibly move between a closed position S (corresponding to the highest position P) and an open position O (corresponding to the lowest position P). In these positions S and O, the window glass 4... Figure 1 The dashed lines indicate the areas in the middle. The solid line represents window 4, which is in a semi-open position.

[0041] In the following text, information regarding spatial orientation is given in the vehicle's coordinate system (vehicle coordinate system) relative to an exemplary installation in the vehicle's side door. In this case, the horizontal axis (X-axis) is oriented along the vehicle's longitudinal direction, the vertical axis (Y-axis) is oriented along the vehicle's lateral direction, and the applied axis (Z-axis) is oriented along the vehicle's height.

[0042] exist Figure 1 In the schematic diagram, the guide rail 14 is approximately parallel to the vehicle height direction Z, but the guide rail 14 is preferably inclined in the Z direction.

[0043] The following will be based on Figure 2 and Figure 3 The structure of the adjustment actuator 6 is described in detail. In this design, the adjustment actuator 6 is specifically designed as a window regulator or rope actuator for driving the rope drum 18.

[0044] The regulating actuator 6 has a transmission housing (rope actuator housing) 22, in which the worm gear 24 is arranged as a transmission component of the worm gear transmission 16. The transmission housing 22 also houses a worm 26 that meshes with the worm gear 24, which is supported by the motor shaft 28 of the electric motor 15. The transmission housing 22 also houses a motor controller 30, i.e., a motor electronics and / or controller, for controlling and / or regulating the operation of the electric motor 15 and the regulating actuator 6. The motor controller 30 can be connected to the vehicle's wiring harness or onboard electrical network via port 32 of the transmission housing 22.

[0045] The electric motor 15 has a metal motor housing 34. The motor housing 34 is designed as a pole cup with a surrounding cup shell 36 and a cup bottom 38, wherein the cup bottom 38 is fixed to the cup shell 36 at its end face and closes the cup shell. In the illustrated embodiment, the cup bottom 38 is engaged with the cup shell 36, for example, by form-fitting and / or force-locking methods (e.g., by press-fitting). Alternatively, the motor housing 34 or the pole cup may also be designed as a one-piece (i.e., a single piece or integral) deep-drawn component.

[0046] The cup bottom 38 is designed as an end cap with a spherical bearing 40. A rotor 40 is housed within the motor housing 34 and is fixedly connected to the motor shaft 28. The motor shaft 28 is rotatably supported within the motor housing 34 by a spherical bearing 42 on the rotor side and a sliding bearing 44 on the transmission side. Within the transmission housing 22, the free end of the motor shaft 28 is supported by an additional sliding bearing 46.

[0047] A permanent magnet, fixedly held in position within the motor housing 34 or on the inner wall of the cup wall 36, forms the stator 48 of the motor 15. Between the rotor 40 and the sliding bearing 44, a commutator 50 with commutator segments (not shown in detail) is fixed to the motor shaft 28. The commutator 50 is driven by (carbon) brushes 52 of the brush system 54. Figure 4 The brush system, in this embodiment, includes two brushes 52.

[0048] Figures 4 to 7 The brush system 54, shown in detail, has a brush holder 56 that is inserted into the motor housing 34 via a form-fitting housing opening 60 through a holder wall 58. The housing opening 60 is located on the end face of the cup wall 36 opposite to the cup bottom 38. The holder bottom 62 of the brush holder 56 substantially and completely covers the housing opening 60 of the motor housing 34, thereby closing the motor housing 34. For this purpose, the holder bottom 62 protrudes from the housing opening 60 of the motor housing 34 by a radial support flange 64, through which the brush holder 56 is supported on the edge of the opening in the cup wall 36.

[0049] Within the central shaft hole 66 region provided on the brush holder 56, the shaft hole is surrounded by a sleeve-shaped, tubular, or hollow cylindrical shaft guide 68, which protrudes axially from the bottom 62 of the holder toward the transmission device 16. The shaft guide 68 extends into the inner side of the housing of the brush holder 56 with a corresponding sleeve portion 70.

[0050] A sliding bearing 44 is arranged in the shaft guide 68. The motor shaft 28, which extends from the shaft guide 68 through the central shaft hole 66, completely encloses the motor housing 34, which houses the brush holder 56, as completely as possible while forming the smallest possible annular gap.

[0051] The brush holder 56 is implemented as an injection molded part, wherein the shaft guide 68 is integrally formed on the bottom 62 of the holder. In addition, the sliding bearing 44 is integrally formed on the shaft guide 68 or the brush holder 56.

[0052] On the end face containing the brush system 54, four radially extending retaining plates 72 are formed at the opening edge of the motor housing 34. These retaining plates are provided with through holes for fixing screws 74, which are used to form screw connections with the transmission housing 22.

[0053] The brush holder 56 has two connecting contact points 76, which rise axially toward the transmission housing 22 on the outer side of the holder bottom 62. The connecting contact points 76 are designed, for example, as knife-type contacts, and automatically engage with the motor controller 30 when the motor 15 is installed or inserted into the transmission housing 22. The connecting contact points 76 are injection molded together with the material of the brush holder 56 or the holder bottom 62.

[0054] For example, Figure 5 As shown, the end of the contact point 76 facing the rotor 40 is designed as an insulated displacement connection, into which electrical connection wires 78 are pressed and in contact. These connection wires 78 belong to or lead to anti-interference elements in the form of choke coils (anti-interference chokes) 80 and anti-interference capacitors 81.

[0055] During operation, the brushes 52 maintain electrical contact with the commutator 50. Each brush 52 is movably arranged in a corresponding (brush) sleeve (brush groove) 82 at the bottom 62 of the support, which partially surrounds the brush along its longitudinal side in a form-fitting manner. Figure 4 As shown, the position of brush 52 and its corresponding sleeve 82 is offset by 180° relative to the motor shaft 28 or shaft guide 68. In other words, the position of brush 52 relative to shaft guide 68 is mirrored. For example, brush 52 is radially pressed against commutator 50 by a spring element (not shown in detail). For this purpose, shaft guide 68 has a corresponding opening or perforation 84 in the area of ​​brush 52.

[0056] Each brush 20 is electrically connected to the choke 80 via a connecting stranded wire 86. The choke 80 itself is connected to the connection contact 76 via other electronic components, such as capacitors or resistors.

[0057] The sliding bearing 44 is formed by additional radial walls of the shaft guide 68, which surround or encircle the motor shaft 28 as sliding surfaces. The sliding bearing 44 has a sliding ring 88 supporting the motor shaft 28, which is centrally held in the shaft guide 68 by four radial struts 90. A pocket-shaped portion 92 is formed between every two adjacent struts 90. The pocket-shaped portion 92 here refers to the closed (radial) wall between two struts 90, whose thickness or wall thickness is smaller than that of the struts 90. The pocket-shaped portion 92 is only illustratively shown by reference numerals in the figures.

[0058] The claimed invention is not limited to the embodiments described above. Instead, those skilled in the art can derive other variations of the invention within the scope of the disclosed claims without departing from the subject matter of the claimed invention. Furthermore, within the scope of the disclosed claims, all individual features described in conjunction with the various embodiments can be combined in other ways without departing from the subject matter of the claimed invention.

[0059] List of reference numerals

[0060] 2. Window regulators

[0061] 4 car windows

[0062] 6 Adjustable Driver

[0063] 8 implementing agencies

[0064] 10 drive components

[0065] 12 cable mechanism

[0066] 14 guide rails

[0067] 15 electric motors

[0068] 16. Worm gear drive or spur gear drive

[0069] 18 rope drums

[0070] 20 steering pulleys

[0071] 22 Transmission device housing

[0072] 24 Worm Gear / Transmission Components

[0073] 26 worm gear

[0074] 28 motor shafts

[0075] 30 motor controller

[0076] 32-port

[0077] 34 Motor Housing

[0078] 36 cup walls

[0079] 38 cup bottom

[0080] 40 rotors

[0081] 42 spherical bearing

[0082] 44 sliding bearing

[0083] 46 sliding bearing

[0084] 48 stator

[0085] 50 commutator

[0086] 52 brush

[0087] 54 brush system

[0088] 56 Brush Bracket

[0089] 58-bracket wall

[0090] 60 housing opening

[0091] 62 bracket bottom

[0092] 64 Support Flanges

[0093] 66 shaft holes

[0094] 68-axis guide

[0095] 70 sleeve section

[0096] 72-Lasting Tablets

[0097] 74 fixing screws

[0098] 76 Contact Points

[0099] 78 connecting cable

[0100] 80 anti-interference choke

[0101] 81 Anti-interference capacitor

[0102] 82 brush holder

[0103] 84 perforations

[0104] 86 connecting stranded wire

[0105] 88 sliding ring

[0106] 90-pole

[0107] 92 bag-shaped parts

[0108] X vehicle longitudinal

[0109] Y vehicle horizontal

[0110] Z Vehicle height direction

[0111] P glass position

[0112] O Open position

[0113] S-sealed position

Claims

1. A brush system (54) for an electric motor (15), the brush system having a brush holder (56) having at least one brush barrel (82) for movably supporting a brush (52), the brush being arranged around a central shaft hole (66) through which a motor shaft (28) passes, wherein the brush holder (56) has an integrally formed sliding bearing (44) for slidably supporting the motor shaft (28) in the region of the shaft hole (66).

2. The brush system (54) according to claim 1. Its features are, The brush holder (56) has a tubular shaft guide (68) that includes the shaft hole (66) and the sliding bearing (44).

3. The brush system (54) according to claim 1 or 2. Its features are, The brush holder (56) is implemented as an injection molded part.

4. The brush system (54) according to any one of claims 1 to 3. Its features are, The sliding bearing (44) has a sliding ring (88) that supports the motor shaft (28), and the sliding ring is connected to the brush bracket (56) by a number of radial support rods (90).

5. The brush system (54) according to claim 4. Its features are, A pocket-shaped portion (92) is formed between every two adjacent support rods (90).

6. An electric motor (15) for a regulating drive (6) of an automobile, the electric motor having a cup-shaped motor housing (34) therein housing a stator (48), a rotor (40) fixed on a motor shaft (28) and a commutator (50) swept by a brush system (54) according to any one of claims 1 to 5.

7. The electric motor (15) according to claim 6. Its features are, The motor housing (34) has a housing opening (60) for the motor shaft (28) on one side, and the brush holder (56) closes the motor housing (34).

8. An adjustment drive (6) for an automobile, the adjustment drive having a transmission housing (22) internally housing a transmission component (24) and an electric motor (15) according to claim 6 or 7, wherein the transmission component (24) is driven by the electric motor (15) via the motor shaft (28).

9. The regulating driver (6) according to claim 8. Its features are, The brush holder (56) is at least partially inserted into the transmission housing (22) such that the sliding bearing (44) is located inside the transmission housing (22).

10. A window regulator (2) for automobiles, the window regulator having an adjustment actuator (6) as a window regulator drive device according to claim 8 or 9.

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