Drive unit

Abstract

To provide a driving device capable of protecting a control circuit from an extraneous noise.SOLUTION: A driving device integrally comprises a motor and a control unit 40 that controls the motor. The control unit 40 includes: a substrate 41 that is arranged on a rotational shaft O of the motor; a motor driving element 55 that performs power conduction to the motor; a power wiring pattern 56 that is connected to the motor driving element 55 to supply power; and a control circuit 61 that transmits a control signal to the motor driving element 55. The control circuit 61 is arranged on a substrate center part 45. The power wiring pattern 56 is arranged on an outer side of a radial direction as compared to the motor driving element 55 in a substrate outer peripheral part 46 to surround the motor driving element 55 and the control circuit 61 in a half circumference or more, and is formed so as to be extended along an outer edge 44 of the substrate 41.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a drive device. [Background technology]

[0002] Conventionally, a control unit including a substrate on which a plurality of electronic components and a power wiring pattern for supplying power thereto are provided is known, for example, as described in Patent Document 1. In Patent Document 1, the substrate is a multi-layer substrate, and the power wiring patterns are arranged on the periphery of a predetermined layer, and the power wiring patterns are arranged facing each other between the layers. The power wiring patterns facing each other between the layers act as a capacitor that utilizes the dielectric constant of the substrate, reducing the impedance of the power supply and absorbing power supply noise. The malfunction of peripheral devices is prevented by suppressing the emission of power supply noise. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2002-94246 A Summary of the Invention [Problem to be solved by the invention]

[0004] Incidentally, in the control unit, it is desirable to protect the control circuit from external noise, and there is room for improvement in this regard.

[0005] The present invention has been made in view of the above-mentioned points, and an object of the present invention is to provide a drive device capable of protecting a control circuit from external noise. [Means for solving the problem]

[0006] The drive device of the present invention integrally comprises a motor (20) and a control unit (40) that controls the motor. The control unit has a substrate (41) arranged on the rotation axis (O) of the motor, a motor drive element (55) that supplies electricity to the motor, a power wiring pattern (56) that is connected to the motor drive element to supply power, and a control circuit (61) that sends a control signal to the motor drive element.

[0007] The portion of the substrate within a predetermined distance from the rotation axis and closer to the rotation axis than the outer edge of the substrate is defined as the substrate center (45). The portion of the substrate other than the substrate center is defined as the substrate outer periphery (46).

[0008] The control circuit is disposed at the center of the substrate, and the power wiring pattern is disposed radially outward from the motor drive element on the outer periphery of the substrate, surrounding the motor drive element and the control circuit by at least half the circumference and extending along the outer edge of the substrate. If the mounting surface of the board opposite the heat sink (33) is defined as a first mounting surface (47) and the mounting surface of the board facing the heat sink is defined as a second mounting surface (48), the motor driving element is disposed on the first mounting surface. The power wiring pattern includes a power supply pattern (57) disposed on the first mounting surface and connected to the high potential side of the motor driving element to supply power, and a ground pattern (58) disposed on the second mounting surface and connected to the low potential side of the motor driving element, the ground pattern being electrically connected by contacting the heat sink.

[0009] This ensures that the power wiring pattern has sufficient conductor capacity to pass a large current, and the motor drive elements and control circuit are surrounded and shielded by conductors with a relatively low impedance, which protects the control circuit from external noise. [Brief description of the drawings]

[0010] [Figure 1] FIG. 2 is a vertical cross-sectional view of the drive device according to the embodiment. [Diagram 2] 2 is a view of the circuit board, electronic components, and screw in FIG. 1 as seen from the direction of arrow II. [Diagram 3] An enlarged view of part III in Figure 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, an embodiment of the drive device will be described with reference to the drawings.

[0012] [One embodiment] 1, the driving device 10 integrally comprises a motor 20 and a control unit 40 that controls the motor 20. The control unit 40 controls the motor 20 to generate a desired torque based on information input from the outside and information such as the motor current detected inside the control unit 40. The torque of the motor 20 is output to the outside from the output end of the rotating shaft 26.

[0013] Motor 20 is a three-phase brushless motor and includes a stator 21, a rotor 25, and a housing 31 that accommodates them. Stator 21 has a stator core 22 fixed to housing 31, and a three-phase winding set 23 assembled to stator core 22. Three-phase winding set 23 is connected to control unit 40 via lead wires (not shown).

[0014] The rotor 25 has a rotating shaft 26 supported by a rear bearing 35 and a front bearing 36, and a rotor core 27 into which the rotating shaft 26 is fitted. The rotor 25 is provided inside the stator 21 and is rotatable relative to the stator 21. A permanent magnet 37 is provided on one end of the rotating shaft 26.

[0015] The housing 31 has a cylindrical case 32, a front end frame 33 provided at one end of the case 32, and a rear end frame 34 provided at the other end of the case 32. The front end frame 33 and the rear end frame 34 are fastened to each other by bolts (not shown). The front end frame 33 also functions as a heat sink for the control unit 40. In the following, when describing the function of the front end frame 33 as a heat sink, it will be referred to as the "heat sink 33" as appropriate.

[0016] As shown in Figures 1 and 2, the control unit 40 has a heat sink 33 and a substrate 41 arranged on the rotation axis O of the motor 20, a screw 51 as a fixing member for fixing the substrate 41, a motor driving element 55 for supplying electricity to the motor 20, a power wiring pattern 56 connected to the motor driving element 55 for supplying power, a control circuit 61 for sending a control signal to the motor driving element 55, and a rotation angle sensor 62 for detecting the rotation angle of the rotating shaft 26.

[0017] The substrate 41 is disposed on the opposite side of the heat sink 33 from the stator 21. In one embodiment, there is only one substrate 41, but in other embodiments, there may be two or more substrates. The screw 51 passes through a through hole 42 in the substrate 41. The motor driving element 55 is composed of a switching element such as a MOSFET, and performs a switching operation in response to a control signal from a control circuit 61 to switch the energized state of the three-phase winding set 23. The control circuit 61 performs calculations based on information from the outside, a rotation angle sensor 62, etc., and generates signals to command the motor driving element 55, etc.

[0018] The control unit 40 further has a cover 64 arranged to cover the board 41 and the electronic components mounted thereon, and a connector 66 for connecting the control unit 40 to the outside.

[0019] The cover 64 protects the control unit 40 from external shocks and prevents the intrusion of dust, water, and the like into the control unit 40. Electronic components other than the motor drive element 55 and the control circuit 61 are not shown in Figures 1 and 2. The connector 66 is fixed to the connector connection portion 43 of the board 41 by a screw 63, and extends out of the cover 64 through an opening 65.

[0020] A portion of the substrate 41 within a predetermined distance from the rotation axis O and closer to the rotation axis O than an outer edge 44 of the substrate 41 is defined as a substrate central portion 45. Further, a portion of the substrate 41 other than the substrate central portion 45 is defined as a substrate outer peripheral portion 46.

[0021] The control circuit 61 is disposed in the substrate central portion 45. In particular, in one embodiment, the control circuit 61 is disposed on the rotation axis O and approximately in the center of the substrate central portion 45.

[0022] The screws 51 are disposed on the outer periphery 46 of the substrate to ensure a sufficient mounting area, and fix the substrate 41 to the heat sink 33. In one embodiment, three screws 51 are provided at intervals in the circumferential direction around the rotation axis O.

[0023] The power wiring pattern 56 and the motor driving element 55 are disposed on the substrate outer periphery 46. The power wiring pattern 56 is disposed radially outward (i.e., closer to the outer edge 44) than the motor driving element 55, and is formed so as to surround the motor driving element 55 and the control circuit 61 by more than half the circumference and extend along the outer edge 44. In particular, in one embodiment, the power wiring pattern 56 is formed over the entire portion of the substrate outer periphery 46 except for the connector connection portion 43.

[0024] The mounting surface of the substrate 41 opposite the heat sink 33 is defined as a first mounting surface 47. The mounting surface of the substrate 41 facing the heat sink 33 is defined as a second mounting surface .

[0025] The motor driving element 55 is disposed on the first mounting surface 47. That is, the motor driving element 55 is disposed on the opposite side of the substrate 41 from the heat sink 33.

[0026] The power wiring pattern 56 includes a power supply pattern 57 arranged on the first mounting surface 47 and connected to the high potential side of the motor driving element 55 to supply power, and a ground pattern 58 arranged on the second mounting surface 48 and connected to the low potential side of the motor driving element 55. The power supply pattern 57 and the ground pattern 58 are arranged facing each other between the substrates 41. The ground pattern 58 is electrically connected by being in contact with the heat sink 33.

[0027] The ground pattern 58 is formed up to the edge of the through hole 42 and is in contact with the screw 51. The ground pattern 58 is directly connected to the heat sink 33, and is also indirectly connected to the heat sink 33 via the screw 51.

[0028] (effect) As described above, in one embodiment, the control circuit 61 is disposed in the substrate central portion 45. The power wiring pattern 56 is disposed radially outward from the motor driving element 55 in the substrate outer periphery 46, and is formed so as to surround the motor driving element 55 and the control circuit 61 by more than half the circumference and to extend along the outer edge 44 of the substrate 41. This ensures that the power wiring pattern 56 has a conductor capacity sufficient to allow a large current to flow, and therefore the motor driving element 55 and the control circuit 61 are surrounded and shielded by a conductor with a relatively low impedance. This makes it possible to protect the control circuit 61 from external noise.

[0029] In one embodiment, the motor driving element 55 is disposed on the first mounting surface 47. The power wiring pattern 56 includes a power supply pattern 57 disposed on the first mounting surface 47 and connected to the high potential side of the motor driving element 55 to supply power, and a ground pattern 58 disposed on the second mounting surface 48 and connected to the low potential side of the motor driving element 55. The ground pattern 58 is electrically connected by contacting the heat sink 33. By electrically connecting the ground pattern 58 to the heat sink 33 in this manner, the impedance of the power wiring pattern 56 is further reduced, and the shielding effect of the power wiring pattern 56 can be further improved.

[0030] In one embodiment, the power wiring pattern 56 is formed over the entire area of ​​the outer periphery 46 of the substrate 41 except for the connector connection portion 43. This allows the substrate 41 to be surrounded and effectively shielded almost entirely.

[0031] [Other embodiments] In another embodiment, the power wiring pattern may be formed to surround the entire periphery of the substrate.

[0032] The present invention is not limited to the above-described embodiment, and can be embodied in various forms without departing from the spirit of the invention. [Explanation of symbols]

[0033] 10 drive device, 20 motor, 33 heat sink, 40 control unit, 41 board, 44 outer edge, 45 board center, 46 board outer periphery, 51 screw (fixing member), 55 motor drive element, 56 power wiring pattern, 61 control circuit, O rotation shaft center.

Claims

1. A drive device integrally comprising a motor (20) and a control unit (40) for controlling the motor, The control unit includes a substrate (41) arranged on a rotation axis (O) of the motor, a motor drive element (55) for supplying electricity to the motor, a power wiring pattern (56) connected to the motor drive element for supplying power, and a control circuit (61) for sending a control signal to the motor drive element, A portion of the substrate within a predetermined distance from the rotation axis and closer to the rotation axis than the outer edge (44) of the substrate is defined as a substrate center (45), and a portion of the substrate other than the substrate center is defined as a substrate outer periphery (46). The control circuit is disposed in the center of the substrate, the power wiring pattern is disposed radially outwardly of the motor drive element in the outer periphery of the substrate, and is formed to surround the motor drive element and the control circuit by at least half a circumference and to extend along the outer edge; The mounting surface of the substrate opposite the heat sink (33) is defined as a first mounting surface (47), and the mounting surface of the substrate on the heat sink side is defined as a second mounting surface (48). the motor drive element is disposed on the first mounting surface, the power wiring pattern includes a power supply pattern (57) disposed on the first mounting surface and connected to a high potential side of the motor driving element to supply power, and a ground pattern (58) disposed on the second mounting surface and connected to a low potential side of the motor driving element, A drive device, wherein the ground pattern is electrically connected to the heat sink by contacting the heat sink.

2. The control unit further includes a connector (66) for connecting the control unit to an external device; The outer periphery of the substrate has a connector connection portion (43) connected to the connector, 2. The drive device according to claim 1, wherein the power wiring pattern is formed over the entire outer periphery of the substrate other than the connector connection portion.

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