JP2007216720A - Electric power steering device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric power steering device having a cover member provided with a part to be fitted to a vehicle and improved so as to be fixed to a side surface of an opening of a gear box at a desirable position, and improved in mounting lay-out performance and having common parts in relation to vehicle models. <P>SOLUTION: The electric power steering device is provided with: the gear box for housing a reduction gear formed of a worm and a worm wheel; and an electric motor fitted to a side surface of the gear box on the warm shaft. The electric power steering device is also provided with: the nearly circular cover member having a fitting part to be fitted to a vehicle so as to be fitted to the side surface of the nearly circular opening of the gear box; a plurality of bolt insertion holes provided with a predetermined interval along the circumferential direction of the cover member; a plurality of bolt holes provided with a predetermined interval along the circumferential direction of the side surface of the opening of the gear box; and bolts to be inserted into the bolt insertion holes and to be screwed to the bolt holes so as to fix the cover member to the side surface of the opening of the gear box. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an electric power steering apparatus that applies steering assist force by an electric motor, and more particularly to an electric power steering apparatus that has an improved mounting structure so that the electric motor does not interfere with the vehicle side when mounted on a vehicle. .

  Conventionally, a hydraulic steering system has been mainly used as a vehicle steering apparatus, but recently, an electric power steering apparatus that assists steering by using an electric motor as a power source has been adopted. Since the electric power steering apparatus uses an electric motor with relatively high rotation and low torque, a speed reduction mechanism such as a worm speed reducer is incorporated between the electric motor and the steering mechanism.

  4 is a partially cutaway side view showing a main part of a conventional electric power steering apparatus, and FIG. 5 is a main part sectional view taken along line VV in FIG. In FIG. 4, the steering shaft 101 is rotatably supported in the steering column 102, and an input shaft 104, an output shaft 105, and a steering shaft 103 are disposed on the proximal end side (left side in FIG. 4) of the steering shaft 101. Are connected. The torsion bar 103 is inserted into the output shaft 105, one end of which is press-fitted and fixed to the input shaft 104, and the other end is fixed to the output shaft 105 by a pin or the like.

  On the outer periphery of the output shaft 105, a speed reduction mechanism 106 is supported in a gear box 109 by a pair of bearings 107 and 108, and a torsion bar 103 is twisted on the tip side (right side in FIG. 4) of the speed reduction mechanism 106. A torque sensor 110 for detecting a magnetic change that occurs is disposed. A cover member 111 that covers the opening of the gear box 109 is attached to the side of the opening (left side in FIG. 4) of the gear box 110 that houses the torque sensor 110 and the speed reduction mechanism 106. It is fixed by being fastened to a bolt hole 114 provided in.

  The speed reduction mechanism 106 is a worm speed reducer including a worm wheel 115 press-fitted and fixed to the outer periphery of the output shaft 105, and a worm 116 meshing with the worm wheel 115. The steering assist electric motor 117 is connected.

In the electric power steering apparatus having such a configuration, the electric motor 117 is driven according to the steering torque detected by the torque sensor 110, and the rotation of the electric motor is decelerated via the worm 116 and the worm wheel 115. The steering shaft 101 is assisted by being transmitted to the output shaft 105.
JP 2000-085596 A

  By the way, in recent years, this type of electric power steering apparatus tends to be employed in various types of vehicles in order to increase the output of the electric motor. However, since the mounting space and mounting layout of the electric power steering apparatus differ depending on the vehicle type, an electric power steering apparatus having a structure that can appropriately cope with such different mounting conditions has been demanded.

  In particular, the electric motor 117 provided on the side of the gear box 109 on the shaft of the worm 116 is a part that easily interferes with the vehicle side when the electric power steering device is attached to the vehicle. In this case, since the mounting phase of the electric motor 117 is uniquely determined, there are many difficulties in layout so that the electric motor 117 does not interfere with the vehicle due to the phase.

  In addition, there is a need to use the gear box 109 in which the mounting position of the electric motor 117 is changed depending on the vehicle type having a different mounting space. Therefore, it is not possible to share the parts and the manufacturing cost increases. There was a problem that.

  As a countermeasure for such a problem, for example, in Patent Document 1, a plurality of mounting holes for a lower bracket are provided in the power-side housing at predetermined intervals in the rotation direction of the power-side shaft, and the electric motor is disposed. Is disclosed that can be changed.

  However, the lower bracket disclosed in Patent Document 1 is only for fixing the power side housing to the vehicle side member, and covers the opening of the gear box 109 like the cover member 110 in FIG. The structure was not such that the output shaft 105 was supported. That is, the power side housing disclosed in Patent Document 1 includes an input shaft side housing and an output shaft side housing, and further includes a lower bracket having a mounting surface having substantially the same diameter as the other end side surface of the output shaft side housing. It was necessary to prepare. Therefore, since the number of parts constituting the gear box increases, there is a problem that it is difficult to reduce the size of the apparatus and that the work for assembling the gear box is not easy.

  Further, since the lower bracket disclosed in Patent Document 1 has only two mounting bolt insertion holes, it is not possible to increase the number of mounting bolts to increase the mounting strength. was there.

  Therefore, the present invention has been made in view of the above circumstances, and an object of the present invention is to improve the cover member provided with the vehicle mounting portion so that it can be fixed to the opening side surface of the gear box at an arbitrary phase. It is another object of the present invention to provide an electric power steering apparatus that improves the mounting layout for a vehicle type and uses common parts.

  The above object of the present invention includes a gear box that houses a speed reduction mechanism including a worm and a worm wheel, and an electric motor attached to a side surface of the gear box on the worm shaft, and the speed reduction is achieved by driving the electric motor. In the electric power steering apparatus configured to assist the steering shaft through a mechanism, the vehicle has a vehicle mounting portion for mounting to the vehicle, and a substantially circular cover member that is attached to a substantially circular opening side surface of the gear box, A plurality of bolt insertion holes provided at predetermined intervals along the circumferential direction of the cover member, a plurality of bolt holes provided at predetermined intervals along the circumferential direction of the opening side surface of the gear box, and The cover member is inserted into the bolt insertion hole and screwed into the bolt hole so that the cover member is opened in the gear box. By providing a bolt for fixing to the surface it is achieved.

  Moreover, the said objective is effectively achieved by the said bolt penetration hole being the arc-shaped long hole formed along the circumferential direction of the said cover member.

  According to the electric power steering apparatus according to the present invention, the cover member having the vehicle attachment portion is provided, and the plurality of bolt insertion holes into which the bolts for fixing the cover member to the opening side surface of the gear box are inserted are provided on the cover member. A plurality of bolt holes provided at predetermined intervals along the circumferential direction and screwed with bolts were provided at predetermined intervals along the circumferential direction of the opening side surface of the gear box. Accordingly, the cover member can be fixed to the gear box with an arbitrary phase, and the phase can be arbitrarily set so that the electric motor does not interfere with the vehicle side when assembled to the vehicle via the vehicle mounting portion. As a result of this improvement in layout, parts can be used in common even for vehicles with different mounting spaces and mounting layouts for the electric power steering device, so that manufacturing costs can be reduced.

  In addition, since both the opening side surface of the gear box and the cover member are provided with a plurality of bolt insertion holes and a plurality of bolt holes at predetermined intervals, the bolts can be used to enhance the mounting strength between the cover member and the gear box. This can be dealt with by increasing the number.

  Furthermore, by making the bolt insertion hole into an arc-shaped elongated hole formed along the circumferential direction of the cover member, it becomes possible to finely adjust the phase, and the electric motor is not only the vehicle side member but also the same engine room. An optimal layout can be realized so as not to interfere with other components mounted inside.

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

  FIG. 1 is a schematic diagram illustrating a configuration of a column portion of an electric power steering apparatus according to an embodiment of the present invention. In the figure, a column portion of the electric power steering apparatus includes a steering column 3 that rotatably supports a steering shaft 2 connected to a steering wheel 1, an electric motor 4 for assisting steering, and a speed reduction of the electric motor 4. And a gear box 6 provided with a speed reduction mechanism for transmitting to the output shaft 5. The electric motor 4 is driven and controlled based on the steering torque input to the steering shaft 2 via the steering wheel 1, and the rotation of the electric motor 4 is output to the output shaft via the speed reduction mechanism housed in the gear box 6. By being transmitted to 5, the steering shaft 2 is assisted.

  Further, one end of an intermediate shaft 8 is connected to the tip of the output shaft 5 (left side in FIG. 1) via a universal joint 7, and the other end of the intermediate shaft 8 is connected via a universal joint 9. A lower steering shaft 10 is connected.

  Further, the gear box 6 has a substantially circular opening on one side surface (left side in FIG. 1) so that a torque sensor and a speed reduction mechanism housed in the gear box 6 can be assembled. A substantially circular cover member 12 is attached via a use bolt 11. The cover member 12 covers the opening of the gear box 6 to support the output shaft 5, and includes a vehicle attachment portion 15 to which a lower bracket 14 for fixing to the vehicle side member 13 is attached. The gear box 6 to which the cover member 12 is attached is fixed to the vehicle side member 13 via the vehicle attachment portion 15 and the lower bracket 14.

  On the other hand, the steering column 3 is fixed to the vehicle side member 13 via the upper bracket 16. A member denoted by reference numeral 17 in FIG. 1 is a tilt lever, and the steering column 3 is released from a tilt adjustment mechanism (not shown) by a driver's operation, and the vehicle mounting portion 15 is used as a fulcrum (tilt pivot). The steering column 3 swings up and down.

  The speed reduction mechanism housed in the gear box 6 is the same as the worm speed reduction device 106 including the worm 116 and the worm wheel 115 shown in FIGS.

  FIG. 2 is a cross-sectional view of a main part along the line AA in FIG. In the drawing, lower brackets 14 and 14 are attached to both ends of a vehicle attachment portion 15 provided on the cover member 12 via a vehicle attachment bolt 18 and a vehicle attachment nut 19, and the cover member 12 is attached to the vehicle side member. 13 is fixed.

  Further, the substantially circular cover member 12 has a plurality of bolt insertion holes 20 through which the cover member mounting bolts 11 are inserted at predetermined intervals along the circumferential direction. A number of bolt insertion holes 20 are formed. On the other hand, in FIG. 2, a bolt hole 21 into which the cover member mounting bolt 11 is screwed is in phase with the bolt insertion hole 20 in the substantially circular opening side portion of the gear box 6 hidden by the cover member 12. A plurality of bolt holes 21 are provided at predetermined intervals along the circumferential direction, more specifically, eight bolt holes 21 are provided at intervals of 45 °.

  Thus, by providing the plurality of bolt insertion holes 20 and the plurality of bolt holes 21 at predetermined intervals along the circumferential direction, the mounting phase between the cover member 12 and the gear box 6 can be arbitrarily changed. . Thereby, the arrangement of the electric motor 4 can be arbitrarily set so that the electric motor 4 attached to the side surface of the gear box 6 on the worm shaft of the speed reduction mechanism does not interfere with the vehicle side member 13 and the like. It is possible to improve the performance.

  Further, in the present embodiment, since the plurality of bolt insertion holes 20 and the plurality of bolt holes 21 are provided so that the phases coincide with each other, the cover member 12 and the gear box 6 are covered with a cover when it is desired to enhance the mounting strength. This can be dealt with by increasing the number of member mounting bolts 11 to 3, 4, and so on.

  In the present embodiment, seven bolt insertion holes 20 are provided every 45 ° along the circumferential direction of the cover member, and every 45 ° along the circumferential direction of the opening side surface of the gear box. However, the present invention is not limited to this, and the bolt insertion holes 20 and the bolt holes 21 may be spaced at predetermined intervals so that the phases match each other. For example, every 30 ° intervals. Alternatively, the bolt insertion hole 20 and the bolt hole 21 may be provided at intervals of 60 °.

  Further, in the present embodiment, the mounting structure of the gear box 6 and the cover member 12 of the column assist type electric power steering apparatus has been described. However, the present invention is not limited to this, and for example, the pinion assist type electric power steering apparatus It can also be applied as a mounting structure for a gear box and a cover member.

  Next, a modification of this embodiment will be described with reference to FIG. In the figure, the same members as those in FIGS. 1 and 2 are denoted by the same reference numerals, and the description thereof is omitted.

  FIG. 3 shows a modification of the embodiment of the present invention, and is a cross-sectional view of the main part along the line AA in FIG. In the figure, the substantially circular cover member 12a has a plurality of arc-shaped long holes 20a through which the cover member mounting bolts 11 are inserted at predetermined intervals along the circumferential direction. Seven arc-shaped long holes 20a are formed in each of them. This arc-shaped long hole 20a is formed along the circumferential direction of the cover member 12a. On the other hand, in FIG. 3, a bolt hole 21 into which the cover member mounting bolt 11 is screwed is in phase with the arc-shaped elongated hole 20 a in the substantially circular opening side portion of the gear box 6 hidden by the cover member 12 a. A plurality of bolt holes 21 are provided at predetermined intervals along the circumferential direction, specifically, eight bolt holes 21 are provided at intervals of 45 °.

  Therefore, in the modification of FIG. 3, the bolt insertion hole 20 of FIG. 2 is an arc-shaped long hole 20 a formed along the circumferential direction of the cover member 12. In addition to being obtained, it is possible to finely adjust the mounting phase, and an optimal layout according to the mounting space of the vehicle can be realized.

  As mentioned above, although embodiment of this invention was described concretely, this invention is not limited to this, In the range which does not deviate from the meaning, it can change suitably.

It is the schematic which shows the structure of the column part of the electric power steering apparatus which concerns on embodiment of this invention. It is principal part sectional drawing along the AA in FIG. The modification of embodiment of this invention is shown and it is principal part sectional drawing along the AA in FIG. It is a partially broken side view which shows the principal part of the conventional electric power steering apparatus. It is principal part sectional drawing along the VV line in FIG.

Explanation of symbols

2 Steering shaft 4 Electric motor 6 Gear box 11 Cover member mounting bolt 12 Cover member 13 Vehicle side member 15 Vehicle mounting portion 20 Bolt insertion hole 20a Arc-shaped long hole 21 Bolt hole 106 Deceleration mechanism 115 Warm wheel 116 Warm

Claims (2)

A gear box that houses a speed reduction mechanism including a worm and a worm wheel; and an electric motor attached to a side surface of the gear box on the worm shaft, and the steering shaft is driven via the speed reduction mechanism by driving the electric motor. In the electric power steering device designed to assist,
A substantially circular cover member having a vehicle attachment portion for attachment to a vehicle and attached to a substantially circular opening side surface of the gear box;
A plurality of bolt insertion holes provided at predetermined intervals along the circumferential direction of the cover member;
A plurality of bolt holes provided at predetermined intervals along the circumferential direction of the opening side surface of the gear box;
An electric power steering apparatus comprising: a bolt that is inserted into the bolt insertion hole and is screwed into the bolt hole to fix the cover member to the opening side surface of the gear box. The electric power steering apparatus according to claim 1, wherein the bolt insertion hole is an arc-shaped elongated hole formed along a circumferential direction of the cover member.

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