Electric motor

Abstract

An electric motor (21) arranged on a vehicle (13), comprising: a bracket (24) in which a rotating shaft (26) is arranged; a housing (36) connected to the bracket; a speed reduction mechanism housing unit (36b) in the housing, wherein a speed reduction mechanism (41) for reducing the rotational speed of the rotating shaft is arranged in the speed reduction mechanism housing unit; a switchboard housing unit (36c) arranged in the housing and a circuit board (51) for controlling a rotation of the rotating shaft; a metal cover element (43) which is arranged between the speed reduction mechanism and the circuit board to cover the speed reduction mechanism housing unit; and a metal contact plate (60) which is held between the bracket and the housing, the cover element is grounded to a vehicle body by means of the contact plate.

Description

[0001] The present invention relates to an electric motor comprising a bracket in which a rotation axis is arranged, and a housing in which a reduction mechanism and a circuit board are arranged.

[0002] Typically, an electric motor with a speed reduction mechanism is often used as a drive source for a sunroof device, etc. Such electric motors of sunroof devices, etc., include a bracket in which an armature shaft (rotating shaft) is rotatably mounted; and a gear case (housing) connected to the open end of the bracket, in which a speed reduction mechanism for reducing the rotation speed of the armature shaft is arranged. A mechanism including a worm gear rotated by the armature shaft; and a worm gear with gear teeth meshing with the worm gear are used as the speed reduction mechanism, producing relatively high power despite their compact structure.

[0003] In addition, when opening and closing the sunroof, which is an openable and closing element, it is necessary for an electric motor in the sunroof device, etc., to detect the opening and closing movement of the sunroof and control the rotation of the armature shaft. For this purpose, a control panel (printed circuit board) is provided to meet these requirements. The control panel, together with the speed reduction mechanism, is arranged in the gear case and is protected from exposure to rainwater, dust, etc. Furthermore, a gear cover (cover member) is provided between the speed reduction mechanism and the control panel, preventing lubricating oil such as grease applied to the speed reduction mechanism from spreading toward the control panel.

[0004] Such electric motors with a gear cover between the speed reduction mechanism and the control panel are disclosed, for example, in Patent Document 1 (JP 2010-57299 A, Fig. 3) is described as prior art. According to the electric motor disclosed in Patent Document 1, the gear cover is formed from a steel plate by pressing, etc., and a plurality of fitting claws are provided substantially on the periphery of the gear cover and fitted into the respective fittings of the resin gear cover, so that the gear cover is firmly fixed to the housing cover and prevents rattling.

[0005] In the electric motor disclosed in Patent Document 1, when external noise such as static electricity penetrates a fixed part such as an installed leg of an electric motor mounted on a vehicle and further propagates into the interior of the electric motor, the external noise may be reflected by the metal cover member and then reach various parts (unspecified parts) of the circuit board. Therefore, it is necessary to prevent malfunctions of the circuit board and prevent external noise reaching the cover member from being reflected onto the circuit board.

[0006] Patent Document 2 (DE 101 25 582 A1) discloses a drive device, Patent Document 3 (DE 195 48 829 A1) discloses a plastic housing, and Patent Document 4 (JP 2010-141 969 A) shows an electric motor with a reduction gear. Patent Document 5 (DE 696 01 270 T2) discloses a geared motor, in particular for driving a motor vehicle windshield wiper.

[0007] The object of the present invention is to provide an electric motor that can prevent external noise reaching a cover member from being reflected to various parts of the circuit board and thus further increase the reliability of the electric motor.

[0008] An electric motor according to one aspect of the present invention comprises: a bracket in which a rotating shaft is housed; a housing connected to the bracket; a speed reduction mechanism housing unit provided in the housing, the speed reduction mechanism for reducing the rotation speed of the rotating shaft being housed in the speed reduction mechanism housing unit; a conductor housing unit provided in the housing and a circuit board for monitoring the rotation of the rotating shaft; and a metal cover member is provided to cover the speed reduction mechanism housing unit, the grounded cover member being provided between the speed reduction mechanism and the circuit board.

[0009] In another aspect of the present invention, a metal contact plate is provided with a terminal disposed between the bracket and the housing, and the terminal is connected to the cover member.

[0010] In another aspect of the present invention, the housing has a fitting, the cover member has a fitting claw which is fitted into the fitting of the housing, and the data transmission device is connected to the fitting claw.

[0011] According to the present invention, a grounded metal cover member is provided to cover the speed reduction mechanism housing unit between the speed reduction mechanism and the circuit board. With this structure, even if external noise such as static electricity penetrates the electric motor and reaches the cover member, the external noise is quickly conducted to the outside of the electric motor. This makes it possible to reliably prevent external noise from being reflected to the circuit board and causing malfunctions of the circuit board or the like, thereby improving the reliability of the sunroof motor 21. Fig. 1 is an explanatory schematic diagram showing the sunroof device in the roof of the vehicle; Fig. 2 is a plan view with details of the sunroof motor of Fig. 1; Fig. 3 is an exploded view of the sunroof motor of Fig. 2; Fig. 4 is a perspective view showing the connection between a case cover and a circuit board; and Fig. 5 is an enlargement of part “A”, which is shown in Fig. 2 is outlined.

[0012] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

[0013] Fig. 1 is an explanatory schematic diagram showing a sunroof device for the roof of a vehicle. Fig. 2 is a plan view showing details of the sunroof motor of Fig. 1 shows. Fig. 3 is an exploded view of the sunroof motor of Fig. 2. Fig. 4 is a perspective view showing the relationship between the gear cover and the circuit board and Fig. Figure 5 is an enlarged view of part “A” which is shown in Fig. 2 is marked by a circle.

[0014] As in Fig. 1, the sunroof device 11 includes a roof panel (sunroof) 12 through which an opening 14 in the roof 13a of the vehicle 13 is opened and closed.

[0015] A pair of hinges 15a and 15b and another pair of hinges 15a and 15b are fixed to the respective sides of the roof panel 12, and two guide rails 16 facing the respective longitudinal direction of the vehicle are fixed to the respective sides of the opening 14 of the roof 13a. The pairs of hinges 15a and 15b are guided by respective guide rails 16. Therefore, the roof panel 12 is freely movable, namely openable and closable in the longitudinal direction of the vehicle.

[0016] One end of the drive cables 17a and 17b, each provided with a gear, is connected to the rear of the hinge 15b, while the other end of the drive cables 17a and 17b is arranged on the front of the opening 14 of the vehicle.

[0017] A sunroof motor 21, which is an electric motor, is arranged on the inside of the roof 13a and between the windshield 13b and the opening 14, and closer to the front of the vehicle than the opening 14. Each of the drive cables 17a and 17b is coupled to a power unit 22 arranged on the sunroof motor 21. When the sunroof motor 21 is actuated, the drive cables 17a and 17b are guided in different directions to the opposite sides of each other. As a result, the roof panel 12 is pushed and pulled by the drive cables 17a and 17b to open and close the opening 14.

[0018] As in the Fig. 2 and Fig. As shown in Figure 3, the sunroof motor 21 includes a motor body 23, which is a brushed motor. A bracket 24, which constitutes the motor body 23, is formed by pressing a steel plate, etc., into a cylindrical base with a shape that is nearly elliptical in diameter. An armature 25 is rotatably mounted in the bracket 24 and is rotatable.

[0019] An armature shaft (rotating shaft) 26 extends to penetrate the rotation center of the armature 25 and is fixed to the armature 25. The armature shaft 26 is rotatably received in the bracket 24. One end of the armature shaft 26 is rotatably supported by a bearing (not shown) on the lower part 24a of the bracket 24.

[0020] An armature plate 27 is wound with several armature tracks 28 and fixed to the armature shaft 26. Furthermore, a commutator 29 is fixed to the armature shaft 26 next to the armature plate 27, and each end of the armature coil 28 is connected to the commutator 29.

[0021] A brush device 31, which supplies electrical energy to the armature 25, namely the armature coil 28, is attached to the open end of the bracket 24. In the brush device 31, a brush holder 32 with a plurality of brushes 33a and 33b (only two brushes are in Fig. 2) are provided, which are movable. Each of the brushes 33a and 33b is in sliding contact with the outside of the commutator 29. A drive current is passed at the appropriate time through the brushes 33a and 33b, and the commutator 29 is supplied to the armature coil 28.

[0022] A gear case 36 serves as a housing and is connected to the open end of the bracket 24 via a pair of fastening screws 34a and 34b. The gear case 36 is made of resin material and shaped similar to a tub. A case cover (not shown) is connected to the gear case 36 via five locking claws 36a. In this way, an open part of the gear case 36 is closed with the case cover to prevent rainwater, dust, etc. from entering the gear case 36.

[0023] The open end of the bracket 24 is substantially formed with a flange 37 extending outward in the radial direction of the open end. The mounting bolts 34a and 34b extend to penetrate the flange 37. The gear housing 36 has a pair of nuts (not shown) coupled to the respective mounting bolts 34a and 34b.

[0024] A speed reduction mechanism 41 is rotatably mounted in the gear housing 36. The speed reduction mechanism 41 consists of: a worm shaft 41b with an external shape as a worm 41a; and a worm shaft 41d with an external shape as a gear tooth 41c, which interacts with the worm 41a.

[0025] The other end of the armature shaft 26 is connected to one end of the worm shaft 41b via a connecting element 41e, so that the worm shaft 41b rotates substantially with the armature shaft 26. A thrust shaft 42 is connected to a rotation center of the worm shaft 41d such that the worm shaft 41d can rotate substantially with the thrust shaft 42. One end of the thrust shaft 42 extends from the lower part of the gear cover 36 to the outside, and the engine 22 (see Fig. 1) is fixed to the protruding part of the thrust shaft 42. In this way, the rotation of the armature shaft 26 is transmitted to the speed reduction mechanism 41 and is reduced in speed by the speed reduction mechanism 41. Therefore, a torque of the thrust shaft 42 is transmitted via the engine 22 as an increased torque to each of the drive cables 17a and 17b.

[0026] A nearly cylindrical worm gear housing unit 36b is disposed in the gear housing 36. In the present invention, the worm gear housing unit 36b constitutes a speed reduction mechanism housing unit, and the worm gear 41d constituting the speed reduction mechanism 41 is rotatably supported in the worm gear housing unit 36b.

[0027] A control panel housing unit 36c, in which a nearly vertical control panel (printed circuit board) 51 is housed, is arranged in the gear case 36. The control panel housing unit 36c is arranged in series with the worm gear housing unit 36b in the axial direction of the thrust shaft 42, so that this worm gear housing unit 36b is arranged closer to the lower part of the gear case 36, and the control panel housing unit 36c is arranged closer to the opening of the gear case 36.

[0028] A gear housing (housing member) 43 is arranged at an open end of the worm gear housing unit 36b so that it is on the same side as the worm gear housing unit 36b in Fig. 2, which is closer to the housing cover. The gear case 43 is provided such that the open end of the worm gear housing unit 36b is covered, so that the housing cover 43 is interposed between the worm gear 41d arranged in the worm gear housing unit 36b and the control panel 51 arranged in the control panel housing unit 36c, whereby lubricating oil (not shown) such as grease supplied to the speed reduction mechanism 41 is prevented from leaking toward the control panel 51, etc., in the gear case 36.

[0029] The gear cover 43 is made of a thin metal plate (steel plate, etc.) and has an almost disc-like shape due to pressing, etc. The gear cover 43 consists of: a main body 43a; and first, second, third, and fourth fitting claws 43b, 43c, 43d, and 43e formed in the vicinity of the main body 43a. As shown in Fig. As shown in Figure 4, each part of the fitting claws 43b to 43e is curved substantially at a right angle, with each of the fitting claws 43b to 43e having an approximately L-shaped diameter. At the end of each fitting claw 43b to 43e, a taper "TP" is formed, giving each of the fitting claws 43b to 43e a conical shape.

[0030] In the fitting claws 43b to 43e, the first fitting claw 43b is designed such that its lower part points in the axial direction of the armature shaft 26 (in the direction of the arrow “B” in Fig. 4) and thereby allowing the end portion of the first fitting claw 43b to contact the end portion of the clamping point 62 of the contact plate 60, which will be described later. The first, second, third, and fourth fitting claws 43b, 43c, 43d, and 43e are respectively inserted into the first, second, third, and fourth fittings 36d, 36e, 36f, and 36g, which are formed substantially in the vicinity of the worm gear housing unit 36b of the gear housing 36. Immediately after insertion in this manner, each fitting claw 43b to 43e is held firmly and prevented from coming out. Due to the taper "TP," the fitting claws 43b to 43e can be readily fitted into the respective fittings 36d to 36g.

[0031] As in the Fig. 2 and Fig. 3, the metal contact plate 60 is provided between the bracket 24 and the gear housing 36 and is held between the bracket 24 and the gear housing 36 by fastening screws 34a and 34b. As shown in Fig. 4, the contact plate 60 has an annular main body 61 formed, for example, by pressing a steel plate, brass, etc., which has a high conductivity in the given shape and is held between the bracket 24 and the housing cover 36, and the clamping point 62 is bent so as to extend in the direction perpendicular to the annular main body 61.

[0032] The annular main body 61 is formed with a pair of screw recesses 61a into which the fastening screws 34a and 34b are respectively inserted after the sunroof motor 21 (see Fig. 2). In this way, the contact plate can be precisely inserted between the bracket 24 and the gear housing 36 without any positional changes.

[0033] Furthermore, the annular main body 61 has four contact parts 61b, with which four contact parts (not shown) of the brush device 31 are in electrical contact. As a result, brush noise “BN” (see Fig. 5) generated at the brush device 31 are passed on to the contact plate 60.

[0034] The clamping point 62 is designed such that the end part points in the axial direction of the armature shaft 26 (direction of the arrow “B” in Fig. 4) when the sunroof motor 21 is in its assembled state, allowing the clamping point 62 to be connected to the first fitting claw 43b of the gear cover 43. As shown in Fig. 5, the end portion of the clamping point 62 is formed in the first fitting 36d of the gear housing 36 via a clamping fitting hole (not shown) in the gear housing 36.

[0035] In Fig. 5, the metal gear housing cover 43 and the metal contact plate 60 are shaded with dots to facilitate identification of the gear cover 43 and the metal contact plate 60.

[0036] As in the Fig. 2 and Fig. 3, the control panel 51 in the control panel housing unit 36c is adapted to control the rotation of the armature shaft 26 constituting the motor main body 23. The control panel 51 is equipped with a control circuit (not shown) to control the drive current supplied to the armature coil 28, namely the electric power supplied to the brushes 33a and 33b. The control circuit includes a rotation sensor (not shown), etc., which detects the rotation of the armature shaft 26. The brush device 31 is provided with a pair of current terminals 53 and 54 (see Fig. 2) and the control panel 51 has a pair of connecting parts 55 and 56 (see Fig. 5). When arranging and fixing the control panel 51 in the control panel housing unit 36c, the connecting parts 55 and 56 are connected to the respective power terminals 53 and 54, and the control panel 51 is electrically connected to the brushes 33a and 33b.

[0037] Each of the current terminals 53 and 54 of the brush device 31 is formed in a plate and arranged such that its long side faces the axial direction of the armature shaft 26 and its short side (width direction) faces a direction perpendicular to the opening direction of the gear case 36, the current terminals 53 and 54 are connected to the respective connecting parts 55 and 56 and improve the assembly efficiency of the sunroof motor 21.

[0038] When the sunroof motor 21 is in its assembled state, a grounding connection part 57 (see Fig. 3 and Fig. 5) are provided on the opposite sides of the control panel 51 to the connecting terminals 62. The grounding terminal 57 has the same shape as the connecting parts 55 and 56. Therefore, the connecting terminal 62 is formed such that its long side faces the axial direction of the armature shaft 26 and its short side (width direction) faces a direction perpendicular to the direction of the opening of the gear housing 36, whereby the connecting terminal 62 is connected to the grounding terminal 57.

[0039] A connector 58, to which an external connector (not shown) is connected, is arranged on a longitudinal side of the switch panel 51 opposite the ground terminal 57. A power supply (not shown) such as a battery in the vehicle 13 and a sunroof switch (not shown), etc., arranged in the vehicle compartment are connected to the connector 58. The ground terminal 57 is grounded (grounded) by connection to the body (such as a roof 13a) of the vehicle 13 via the switch panel 51 and the connector 58. In other words, the transmission cover 43 is grounded via the ground terminal 57, the switch panel 51, and the connector 58.

[0040] In this way, the terminal clamp 62 of the contact plate 60 is electrically connected to the ground terminal part 57 of the switchboard 51. This results, as in Fig. 5, the dashed arrows indicate that brush noise "BN" from the annular body 61 of the contact plate 60 and external noise "ON" are conducted to the metal cover 43 and to the grounding terminal 57, respectively. Then, the brush noise "BN" and the external noise "ON" which were conducted to the grounding terminal 57 are introduced into the roof 13a etc. (vehicle body) of the vehicle 13 via the switchboard 51 and the connector 58, as shown in Fig. 5 indicated by the dashed arrows.

[0041] The reference symbol “IL” as in Fig. 2, denotes installation legs for fixing the sunroof motor 21 to the inside of the roof 13a (see Fig.1). The mounting legs "IL" are arranged on opposite sides of each other beyond the worm gear housing unit 36b. Each of the mounting legs "IL" is fixed to the inside of the roof 13a with a fastening screw via metal sleeves (both the screw and sleeve are not shown). External interference "ON," such as static electricity, can easily enter the sunroof motor 21 via the mounting legs "IL."

[0042] Then, when the sunroof switch is operated and turned over by a driver or the like, a drive current is supplied to the switch board 51 from the power supply via the connector 58, the control circuit controls the drive current so that a given current can be supplied to the armature coils 28 via the connecting parts 55 and 56, the power terminals 53 and 54, the brushes 33a and 33b and the commutator 29.

[0043] As described above, in the sunroof motor 21 according to the previous embodiment, the grounded metal housing cover 43 covering the worm gear housing unit 36b is provided between the worm gear 41d and the control panel 51. In this form, even if external noise "ON" such as static electricity enters the sunroof motor 21 and reaches the housing cover 43, the external noise "ON" is relatively quickly eliminated and conducted to the outside of the sunroof motor 21. Thus, the external noise "ON" can be reliably prevented from being reflected by the control panel 51 and causing a malfunction of the control panel 51 or the like, thereby enhancing the reliability of the sunroof motor 21.

[0044] Furthermore, in the sunroof motor 21 according to the previous embodiment, the metal contact plate 60 with the clamping points 62 is provided between the bracket 24 and the gear housing 36, and the clamping point 62 is connected to the housing cover 43. In this embodiment, brush noise "BN" from the motor body 23 is quickly transmitted to the outside of the sunroof motor 21.

[0045] Furthermore, in the sunroof motor 21 according to the previous embodiment, the housing cover 43 has fitting claws 43b to 43e, which are respectively fitted into the fittings 36d to 36g of the gear case 36, and the clamping point 62 is connected to the first fitting claw 43b. In this embodiment, the clamping point 62 is simply electrically connected to the first fitting claw 43b by simply inserting the fitting claws 43b to 43e into the respective fittings 36d to 36g.

[0046] The present invention is not limited to the foregoing embodiments, and any variations or modifications of this invention will be apparent to those skilled in the art without departing from the scope of the invention. For example, in the foregoing embodiment, external noise "ON" and brush noise "BN," which are conducted to the contact plate 60 via the ground terminal 57 and the connector 58 on the switch panel 51, are eliminated and are conducted into the roof 13a of the vehicle 13 (e.g., to the grounded conductor). However, the present invention is not limited to this example. Since it is essential to conduct the various noises conducted to the contact plate 60 to the body of the vehicle 13, various noises can be introduced into the body of the vehicle 13 via fastening screws 34a and 34b, which are brought into contact with the contact plate 60.In this case, it is possible to eliminate the noise without using the grounding terminal 57 and to simplify the structures of the control panel 51 and the connector 58.

[0047] In this embodiment, the present invention is applied to a sunroof motor 21 for a sunroof device 11 of a vehicle 13. However, the present invention can also be applied, for example, to an electric motor for a sliding door device, power window devices, etc. in a vehicle.

[0048] The electric motor is used as the driving force for a sunroof device etc. in a vehicle such as a car and is operated to open and close a roof panel by pushing or pulling drive cables.

Claims

[1] An electric motor (21) arranged on a vehicle (13), comprising: a bracket (24) in which a rotating shaft (26) is arranged; a housing (36) connected to the bracket; a speed reduction mechanism housing unit (36b) in the housing, wherein a speed reduction mechanism (41) for reducing the rotational speed of the rotating shaft is arranged in the speed reduction mechanism housing unit; a control panel housing unit (36c) arranged in the housing and a circuit board (51) for controlling rotation of the rotating shaft; a metal cover member (43) disposed between the speed reduction mechanism and the circuit board to cover the speed reduction mechanism housing unit; and a metal contact plate (60) held between the bracket and the housing, wherein the cover element is grounded to a vehicle body by means of the contact plate. [2] Electric motor according to claim 1, wherein the contact plate has a clamping point (62) extending to the cover element, the housing has a fitting (36d, 36e, 36f, 36g), and the cover element has a fitting claw (43b, 43c, 43d, 43e) adapted in the fitting of the housing and electrically connected to the clamping point to the contact plate.

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