JP2005112028A - Electric power steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric power steering device having a lid to protect electric equipment between an ECU and a gear box and capable of enhancing the working efficiency when changing the ECU, saving the space, and reliably protecting a torque sensor substrate. <P>SOLUTION: The electric power steering to give the auxiliary steering force to a steering shaft via a reduction gear by driving an electric motor comprises a control unit (ECU) to store a controller to control the operation of the electric motor and a gear box to store the steering gear, and a lid to protect the electric equipment in the gear box is provided between the control unit (ECU) and the gear box. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a highly reliable electric power steering apparatus in which an electric power steering apparatus has an improved structure for protecting electrical components in a gear box.

  Conventionally, in an electric power steering apparatus, for example, as shown in FIG. 17, a gear box 52 is arranged on one end side (left side of FIG. 17) of a steering column 51, and the rotational displacement amount of the torsion bar 53 is placed in the gear box 52. Electrical components such as a torque sensor board 54 for detecting a steering torque based on the above are provided. When a control unit (hereinafter referred to as ECU) 55 that houses a controller for controlling the operation of the electric motor is disposed separately from the cover 56 that protects the electrical components in the gear box 52, the ECU 55 is inspected. In addition, electrical components such as the torque sensor substrate 54 are protected from dust intrusion (see Patent Document 1).

  However, in the above-mentioned conventional one, the ECU 55 and the torque sensor board 54 must be separately arranged, and there is a problem that the space saving of the apparatus is inferior.

  Therefore, for example, as shown in FIG. 18, a recess 59 is formed by a substantially rectangular rib 58 in the lower portion of the gear box 57, and an electrical component such as the torque sensor substrate 60 is attached to the recess 59 with a bolt 61. ing. The gear box 57 is provided with an ECU 62 outside the torque sensor board 60 (on the left side in FIG. 18). The cover 63 of the ECU 62 and the recess 59 of the gear box 57 accommodate electrical components such as the torque sensor board 60. The sealed space is formed.

A controller 64 is disposed between the gear box 57 and the cover 63 of the ECU 62, and the controller 64 is supported by the ribs 58 and fixed by bolts 65. Further, the controller 64 is provided with a power element 66 for driving the motor, and the power element 66 is formed of a heating element so that heat is transmitted to the outside through the cover 63 of the ECU 62 or through the gear box 57. It has become.
As a result, the cover 63 of the ECU 62 also serves as a lid for electrical components such as the torque sensor board 60, and prevents foreign matter from adhering to the torque sensor board 60 and the like, and the ECU 62 and the torque sensor board 60 are connected to each other. It is arranged in one place to save space for the device.
JP 2002-331945 A

  By the way, when a failure occurs in a part in the ECU 62 in the electric power steering apparatus, it is expensive to replace the entire apparatus. In consideration of environmental problems, it is generally performed to replace only the minimum necessary parts. It has been broken.

  However, in the above conventional device, when replacing or inspecting the components in the ECU 62, if the cover 63 of the ECU 62 is removed, the torque sensor substrate 60 is exposed to the outside from the gap C of the mounting portion of the controller 64, and dust is removed. The intrusion could not be prevented. That is, there is a possibility that foreign matter may adhere to the electrical components such as the torque sensor substrate 60 or the operator may accidentally touch it. Therefore, the worker has to perform part replacement work with great care, and there is a problem that workability is poor.

  Further, in recent years, with the increase in size of mounted vehicles, it has been necessary to increase the output of steering torque, and the amount of heat generated from the ECU tended to increase proportionally. However, in the above conventional structure, the electrical components such as the torque sensor board and the ECU are close to each other, so that the operation characteristics of the electrical components are adversely affected by the heat generated by the ECU. There was a problem that could not be taken.

  Therefore, the object of the present invention is to provide a lid that serves to protect electrical components between the ECU and the gear box, thereby improving work efficiency when replacing the ECU and enabling space saving. The object is to reliably protect the torque sensor substrate.

  In order to achieve the above object of the present invention, an electric power steering device that applies an auxiliary steering force to a steering shaft via a speed reducer by driving an electric motor includes a controller for controlling the operation of the electric motor. A control unit (ECU) and a gear box that houses the steering gear, and a lid that serves to protect electrical components in the gear box is provided between the control unit (ECU) and the gear box. This is achieved effectively.

  The above object is effectively achieved by providing the lid with a plurality of bent portions and fixing the lid to the gear box by a plate spring effect of the bent portions.

  Moreover, the said objective is effectively achieved by the said lid | cover consisting of a material with low heat conductivity.

  Moreover, the said objective is effectively achieved because the said lid | cover comprised the attachment seat for fixing a control unit (ECU) to the said gear box.

  As described above, according to the electric power steering apparatus according to the present invention, since the lid for protecting the electrical components in the gear box is provided between the ECU and the gear box, the space of the apparatus can be saved. be able to. Even when the ECU is removed from the gear box, the electrical components in the gear box are kept sealed by the lid. For this reason, when the ECU is inspected, foreign objects may adhere to the electrical components, Touching electrical components can be prevented. Therefore, when checking the ECU, the work efficiency of the worker is improved. Further, by selecting a material with low thermal conductivity for the lid, even if a large amount of heat is generated in the ECU, it does not adversely affect the electrical components in the gear box. Therefore, it is possible to respond to a request for increasing the steering torque capacity in terms of heat generation countermeasures.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a diagram showing an external appearance of a first embodiment of an electric power steering apparatus A according to the present invention. In FIG. 1, a gear box 2 is arranged adjacent to the electric motor 1. A reduction gear that reduces the rotation of the electric motor 1 and transmits it to the steering shaft 4 rotatably supported in the steering column 3 is housed.

  Further, an ECU 5 is disposed above the gear box 2 (upper side in FIG. 1) as a control unit that houses a controller that controls the rotation of the electric motor 1 based on signals such as a vehicle speed signal and a torque signal.

  Further, as shown in FIG. 2, a recess 7 is formed by a substantially rectangular rib 6 on the side where the ECU 5 is arranged in the gear box 2 (left side in FIG. 2), and the torque sensor substrate 8 is formed in the recess 7. Electrical components such as these are attached with bolts 9. Thus, when the ECU 5 is attached to the gear box 2, a sealed space is formed between the recess 7 of the gear box 2 and the ECU 5, and electrical components such as the torque sensor board 8 are accommodated.

  Further, the torque sensor board 8 and the like arranged in the gear box 2 are connected to the ECU 5 through a harness. As a result, the electrical components such as the torque sensor board 8 can be structured so that the gear box 2 and the ECU 5 are covered in a sealed manner by die casting except for the connection opening of the torque sensor harness.

  As shown in FIG. 3, the substantially plate-like lid (inner lid) 10 is supported by the rib 6 so as to cover the recess 7 of the gear box 2 and is attached to the gear box 2. Accordingly, the lid 10 is arranged between the gear box 2 and the ECU 5 and serves as a cover for protecting the torque sensor substrate 8.

  As shown in FIG. 4, the lid 10 is bent at four locations 10 a, 10 b, 10 c, and 10 d and fixed to the gear box 2 by the reaction force. That is, the lid 10 is warped to the right in FIG. 4 by 10 degrees and 10 degrees at the time of mounting, and the recesses 10 c and 10 d are fitted into the recesses of the gear box 2. Then, the lid 10 is mounted along the shape of the gear box 2, and is fitted to the gear box 2 by the reaction force of 10a and 10b. At that time, the lid 10 is accurately positioned at a predetermined location by the concave and convex shapes of the gearbox 2 and the mounting portion of the ECU 5.

  Here, if the torque sensor substrate 8 is attached with the screw 9, the screwing depth is larger than the gap between the gear box 2 and the lid 10, so that even if the screw 9 is loosened, it will come out of the screw hole. There is no. As a result, in the recess 7, the screw 9 is removed, and a failure such as a short circuit can be prevented by an electrical component such as the torque sensor substrate 8.

  Further, the ECU 5 is placed on an aluminum die cast 5a as a heat sink in order to release heat generated from a heating element such as a power element disposed therein. However, since aluminum has a high thermal conductivity, when it is not desired to transmit heat to the electrical components in the gear box 2, the lid is preferably made of a material having a low thermal conductivity from the viewpoint of blocking heat conduction. For example, the material of the lid may be a metal (28 to 104 W / mK) or a resin having a relatively low thermal conductivity compared to aluminum, but is not limited thereto.

  Therefore, even if a heating element such as a power element is arranged in the ECU 5, electrical components such as the torque sensor board 8 are not adversely affected. Even when the ECU 5 is removed when the ECU 5 is inspected, the electrical components such as the torque sensor board 8 in the gear box 2 are protected by the lid 10, so that foreign matter is mixed into the electrical components or contacted by the operator. Can be prevented, and workability is improved.

  5 and 6 show a second embodiment of the present invention, in which the lid 10 disposed between the gear box 2 and the ECU 5 is fastened and fixed by two screws 21 and 21. FIG. . Also in this case, the same effect as the first embodiment can be obtained.

  7 and 8 show a third embodiment of the present invention, in which a lid 10 disposed between the gear box 2 and the ECU 5 is fixed using a driving rod 22. Also in this case, the same effect as the first embodiment can be obtained.

  9 and 10 show a fourth embodiment of the present invention, in which a convex portion 23 extending downward is formed on the lid 10 disposed between the gear box 2 and the ECU 5, and the rib of the gear box 2 is formed. A recess 24 is formed. And the convex part 23 is engage | inserted in this recessed part 24, and the lid | cover 10 is attached to the gear box 2 and fixed. Also in this case, the same effect as the first embodiment can be obtained.

  FIG. 11 and FIG. 12 show a fifth embodiment of the present invention, which is caulked and fixed to the gear box 2 by a caulking portion 25 along the periphery of the lid 10 disposed between the gear box 2 and the ECU 5. It is like that. Also in this case, the same effect as the first embodiment can be obtained.

  13 to 14 show a sixth embodiment of the present invention. A pair of mounting seats 31, 31 extend in parallel from the rib 6 to the gear box 2, and the ECU 5 is bolted to the gear box 2. 32 and 32 are attached. Further, a lid 10 provided with a controller of the ECU 5 and the like is formed on the upper part of the ECU 5 (upper side in FIG. 13), and a part of the lid 10 is used for releasing heat from a heating element such as a power element to the outside. A heat sink 33 is provided.

  The controller or the like in the ECU 5 is covered with a rectangular box-shaped case 34, and has claws 35 at four corners of the case 34, and the claws 35 are engaged with the engagement portions 36 on the gear box 2 side. The case 34 is attached to the lid 10. At that time, as shown in the arrow direction of FIG. 14, the lid 10 is arranged so as to cover the electrical components of the gear box 2, and is fixed to the gear box 2 with bolts through the bolt insertion holes 37. Thus, when the ECU 5 is inspected, the engagement with the claw 35 is disengaged, and only the case 34 of the ECU 5 is removed from the gear box 2, so that the torque sensor substrate 8 in the gear box 2 and the like are exposed to the outside by the lid 10. The inside of the ECU 5 can be inspected without being exposed, and the same effect as in the first embodiment can be obtained.

  FIGS. 15 and 16 show a seventh embodiment of the present invention. An ECU 5 is arranged in the gear box 2, and the torque sensor board 8 is connected to the bolt 9 on the ECU 5 side (left side in FIG. 16) in the gear box 2. It is fixed by. A mounting seat 41 is arranged between the gear box 2 and the ECU 5. The mounting seat 41 is fixed to the gear box 2 by screwing the screw hole 42 of the gear box 2 and the bolt 41a, and the ECU 5 is fixed to the mounting seat 41 by the bolt 43. Thus, the ECU 5 is fixed to the gear box 2 via the mounting seat 41, and the mounting seat 41 plays a role as a lid for protecting the electrical components in the gear box 2. Further, the mounting seat 41 is provided with a plurality of plate-like heat radiating fins 44, which are formed of aluminum or the like, and efficiently release heat generated in the ECU 5 as a heat sink to the outside. .

  In each of the above embodiments, a motor can be arranged close to the ECU 5, and the distance between the ECU 5 and the motor can be minimized. As a result, current loss due to harness resistance can be minimized, and an improvement in output can be expected.

1 is a side view showing a mounting structure of a gear box and an ECU of an electric power steering device according to a first embodiment of the present invention. It is a figure which shows the state which fractured | ruptured partially by the gearbox and ECU attachment structure of FIG. It is a figure which shows the state which removed ECU with the gearbox and ECU attachment structure of FIG. It is a figure which shows the lid | cover attached to the gear box. It is a figure which shows 2nd Example of this invention and corresponds to FIG. 3 of 1st Example. It is the figure which looked at the attachment structure of the gear box and ECU of FIG. 5 from the side surface, Comprising: It is a figure corresponding to FIG. 2 of 1st Example. It is a figure which shows 3rd Example of this invention and corresponds to FIG. 3 of 1st Example. It is the figure which looked at the attachment structure of the gear box and ECU of FIG. 7 from the side, Comprising: It is a figure corresponding to FIG. 2 of 1st Example. It is a figure which shows 4th Example of this invention and corresponds to FIG. 3 of 1st Example. It is the figure which looked at the attachment structure of the gear box and ECU of FIG. 9 from the side, Comprising: It is a figure corresponding to FIG. 2 of 1st Example. It is a figure which shows 5th Example of this invention and corresponds to FIG. 3 of 1st Example. It is the figure which looked at the attachment structure of the gear box and ECU of FIG. 11 from the side surface, Comprising: It is a figure corresponding to FIG. 2 of 1st Example. It is a perspective view showing the state where the ECU was attached to the gear box according to the sixth embodiment of the present invention. FIG. 14 is a perspective view showing a state in which the ECU and the torque sensor board are removed, with the gear box and ECU mounting structure of FIG. 13. FIG. 10 is a side view showing a seventh embodiment of the present invention and showing a state where an ECU is attached to a gear box. It is a figure which shows the state which partly fractured | ruptured with the attachment structure of the gear box and ECU of FIG. It is a figure which shows the state by which ECU was attached to the conventional steering column. It is a figure explaining the attachment structure of the conventional gear box and ECU.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electric motor 2 Gear box 3 Steering column 4 Steering shaft 5 ECU
7 dent 8 sensor substrate 10 lid 21 screw 22 driving rod 23 convex part 24 concave part 25 caulking part 31 mounting seat 33 heat sink 35 claw 36 engaging part

Claims (4)

In the electric power steering device that applies an auxiliary steering force to the steering shaft via the speed reducer by driving the electric motor,
A control unit (ECU) that houses a controller for controlling the operation of the electric motor; and a gear box that houses the steering gear; and the gear box between the control unit (ECU) and the gear box. An electric power steering apparatus comprising a lid that serves to protect an electrical component inside. The electric power steering apparatus according to claim 1, wherein the lid includes a plurality of bent portions, and the lid is fixed to the gear box by a leaf spring effect of the bent portions. The electric power steering apparatus according to claim 1, wherein the lid is made of a material having low thermal conductivity. The electric power steering apparatus according to claim 1, wherein the lid constitutes a mounting seat for fixing a control unit (ECU) to the gear box.