JP2000168579A - ECU installation structure in electric power steering system - Google Patents

Abstract

(57) [abstract] (with correction) [Problem] EC in electric power steering device
Efficient use of empty space in EC installation structure, EC
Simplified seal structure and improved reliability of each connection between U and torque sensor and ECU and motor, simplified wiring structure and improved noise resistance, improved freedom of layout of motor and mount, cost To reduce the amount of SOLUTION: In a housing 8 of a gear box part 2,
A space A for storing the ECU 11 is provided.
A wiring passage 20 for connecting the ECU 11 and the torque sensor 9 is formed on a wall of the housing 8 surrounding the ECU 11, the ECU 11 and the electric motor 5.
And a wiring passage 18 for connecting them to each other. The space A is the housing 8 of the gear box 2.
In the mount portion forming portion 8b or the torque sensor housing portion 8a.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an installation structure of an ECU in an electric power steering device, and more particularly to an E-installation structure.
The installation of the ECU in the electric power steering device which simplifies and improves the reliability of the seal structure of the connection between the CU and the torque sensor and the connection between the ECU and the electric motor, and improves the degree of freedom in the layout of the electric motor and the mount. Regarding the structure.

[0002]

2. Description of the Related Art In an electric power steering apparatus for a vehicle, a gear box for inputting a steering force from a steering wheel to a steering shaft connected to wheels via a tie rod, and an electric motor for inputting a steering assist force from the electric motor. There is an electric power steering device in which each part is mounted.

In the electric motor section of such an electric power steering apparatus, a rotating shaft of an electric motor for outputting a steering assist force is formed by a hollow shaft, and the steering shaft is inserted into the hollow shaft, and one of the hollow shafts is provided. A ball screw is interposed between the end and the steering shaft, and steering assist force is transmitted from the electric motor to the steering shaft via the ball screw.

On the other hand, in the gear box, a steering input shaft connected to a steering wheel and a steering output shaft having a pinion at one end are connected via a torsion bar, and the pinion is connected to a steering shaft. When the steering wheel is steered by engaging with a rack formed near one end of the steering wheel, the steering shaft moves in the axial direction through the engagement between the rack and the pinion, and the wheel is steered.

At the same time, a relative rotation amount difference occurs between the input shaft and the output shaft due to the turning resistance from the wheel side, and the torsion bar is twisted. The torque sensor detects the torque acting on both ends of the torsion bar based on the amount of torsion, and outputs the signal.

[0006] An output signal from the torque sensor is supplied to an ECU.
(Electronic control unit), the electric motor is controlled by an output signal from the ECU, and the steering shaft is advanced in a direction in which the torque acting on both ends of the torsion bar is eliminated. In this manner, the steering resistance felt by the steering wheel is reduced, and a light feeling of steering can be obtained.

In the electric power steering apparatus of the type described above, the ECU is usually installed near the main body of the internal combustion engine, and is provided between the ECU and the torque sensor and the ECU.
As shown in FIG. 7, between the CU and the motor, long wires 019 and 017 and a waterproof type coupler 04 exposed to the outside are provided.
0 and 041. The gearbox section is provided by these waterproof type couplers 040 and 041.
02 and the electric motor unit 03 are waterproofed.

In FIG. 7, 01 is an electric power steering device, 04 is a steering shaft (rack shaft), 010 is a steering input shaft connected to a steering wheel, and 011 is an ECU. In the housing 08, a torque sensor is accommodated in a torque sensor accommodating portion 08a extending at an angle to the steering shaft 04, and an electric motor is accommodated in the electric motor portion 03.

[0009]

For this reason, the seal mechanisms (waterproof type couplers 040 and 041) are dispersed, which complicates the structure and increases the cost. Further, since the connection portion is exposed to the outside, the bonding reliability is low. Further, since the wirings 017 and 019 are long and easily affected by noise, it is necessary to secure a sufficient shielding property.

The invention of the present application solves the above-mentioned problems of the conventional installation structure of the ECU in the electric power steering apparatus, and simplifies the sealing mechanism for connecting the ECU to the torque sensor and the electric motor. It is an object of the present invention to provide an installation structure of an ECU in an electric power steering device which has improved joint reliability, simplified wiring structure, improved noise resistance, and improved the degree of freedom in the layout of a motor and a mount. And

[0011]

SUMMARY OF THE INVENTION The present invention relates to an installation structure of an ECU in an electric power steering apparatus which has solved the above-mentioned problems. A gearbox section for inputting a steering force from a steering wheel and an electric motor section for inputting a steering assist force from an electric motor are mounted on a steering shaft connected to the wheels via the steering shaft. An installation structure of an ECU in an electric power steering device provided with a torque sensor for detecting torque, wherein a space for storing the ECU is provided in a housing of the gear box portion, and the housing surrounding the space is provided. A wiring passage connecting the ECU and the torque sensor to a wall of the EC; A installation structure of an ECU in the electric power steering apparatus characterized by a wiring passage for connecting the electric motor and has formed therethrough, respectively.

According to the first aspect of the present invention, a space for accommodating the ECU is provided in the housing of the gear box in the electric power steering apparatus, and surrounds the space. A wiring path connecting the ECU and the torque sensor and a wiring path connecting the ECU and the electric motor are formed through the wall of the housing.

As a result, the connection between the ECU and the torque sensor and the connection between the ECU and the motor are housed in the housing of the gear box without being exposed to the outside. Is unnecessary, and the seal mechanism need only be applied to the ECU storage section. This simplifies the seal mechanism and improves the joining reliability. In addition, the cost can be reduced.

Further, the connection wiring is shielded from the outside by passing through the housing internal passage of the gear box portion, so that the connection wiring is less affected by noise and the noise resistance of the connection wiring is improved.

Further, according to the second aspect of the present invention, the housing of the gear box portion includes a torque sensor accommodating portion accommodating the torque sensor, and a motor portion extending from the torque sensor accommodating portion. And a mount portion forming portion having a mount portion formed outside, and a space for storing the ECU is provided in the mount portion forming portion.

As a result, a space for accommodating the ECU can be ensured by effectively utilizing the empty space between the torque sensor accommodating portion of the housing of the gear box portion and the electric motor portion. Further, the wiring for connecting the ECU and the torque sensor and the wiring for connecting the ECU and the electric motor can be minimized.

According to the third aspect of the present invention, the housing of the gear box section includes a torque sensor accommodating section accommodating the torque sensor, and a motor section extending from the torque sensor accommodating section. , And a mount portion forming portion having a mount portion formed outside, and a space for storing the ECU is provided in the torque sensor housing portion.

As a result, since neither the ECU housing part nor the coupler connection part is arranged between the torque sensor housing part of the housing of the gear box part and the electric motor part, the electric motor part is arranged close to the torque sensor housing part side. Thus, the size and weight of the electric power steering device can be reduced. In addition, the arrangement and formation positions of the electric motor section and the mount section can be freely selected, and the degree of freedom in layout is improved.

Further, according to the fourth aspect of the present invention, the space for accommodating the ECU is provided below the torque sensor, and is formed on a partition wall separating the ECU and the torque sensor. A cutout hole is formed, and the castout hole serves as a wiring passage connecting the ECU and the torque sensor.

As a result, a space for accommodating the ECU can be secured by effectively utilizing the space on the side of the steering shaft and the space below the torque sensor. In particular, regarding the empty space on the side of the steering shaft, at a position where the steering output shaft and the steering shaft are transmission-coupled through meshing of gears by a pinion and a rack, etc., both sides of the steering output shaft (as viewed in the axial direction of the steering shaft). Vacant space is generated on both sides), and this vacant space can be used effectively.

In addition, since it is not necessary to form a wiring passage for connecting the ECU and the torque sensor in a partition separating the ECU and the torque sensor, it is possible to further reduce the cost. In addition, the size can be freely selected.

[0022]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment (Embodiment 1) of the invention described in claims 1 and 2 of the present application shown in FIGS. 1 to 3 will be described below. FIG. 1 is a vertical cross-sectional view of an electric power steering apparatus to which an ECU installation structure according to the present embodiment is applied, which is a partial side view, and FIG. 2 is a gear box portion of FIG. FIG. 3 is a plan view of a portion of the torque sensor accommodating portion of the housing, in which a cover below the split surface is viewed in a plan view, and FIG. 3 is surrounded by a dashed line in FIG. It is an enlarged view of a part.

1 to 3, an electric power steering apparatus 1 to which an ECU installation structure according to the first embodiment is applied includes a steering shaft 4 connected to wheels via tie rods (not shown), and a steering shaft (not shown). A gear box unit 2 for inputting a steering force from a wheel and an electric motor unit 3 for inputting a steering assist force from an electric motor 5 are mounted respectively. The steering shaft 4 is provided with a rack 4a to be described later near one end thereof, and is configured as a rack shaft.

In the electric motor section 3, a rotating shaft of the electric motor 5 for outputting a steering assist force is formed by a hollow shaft 6. The steering shaft 4 is inserted into the hollow shaft 6, and one end of the hollow shaft 6 is provided. A ball screw 7 is interposed between the section and the steering shaft 4, and steering assist force is transmitted from the electric motor 5 to the steering shaft 4 via the ball screw 7.

The housing 8 of the gear box 2 has a torque sensor housing portion 8a for housing the torque sensor 9.
And a mount forming portion 8b. The mount portion forming portion 8b extends in the direction of the electric motor portion 3 at an angle with respect to the axial direction of the torque sensor housing portion 8a, and a mount portion 23 for attachment to the vehicle body is formed to protrude outside. These are all integrally formed except that the top cover (upper half) 24 of the torque sensor housing portion 8a is formed separately at the position of the split surface B.

The mount portion forming portion 8b accommodates a part of the steering shaft 4 movably in the axial direction thereof, and has an ECU storage portion 12 for storing an ECU (electronic control unit) 11 described later.

In the torque sensor accommodating portion 8a, although not shown in detail, a steering input shaft 10 linked to a steering wheel and a steering output shaft having a pinion at one end are connected via a torsion bar. The pinion meshes with a rack 4a formed near one end of the steering shaft 4, and when the steering wheel is turned, the pinion and the rack 4a are engaged.
The steering shaft 4 moves in the axial direction through the meshing with a, and the left and right wheels are steered.

At the same time, a relative rotation amount difference occurs between the input shaft 10 and the output shaft due to the turning resistance from the wheel side, and the torsion bar is twisted. The torque sensor 9 detects the torque acting on both ends of the torsion bar based on the amount of twist, and inputs the signal to the ECU 11.

Then, according to the output signal from the ECU 11,
The electric motor 5 is controlled, and the output of the electric motor 5 is transmitted to the steering shaft 4 via the ball screw 7. The steering shaft 4 moves in either the left or right direction in FIG. 1 so that the torque acting on both ends of the torsion bar is canceled.

In this manner, the steering resistance felt by the steering wheel is reduced, and a light feeling of steering can be obtained. The structure in the torque sensor accommodating portion 8a and the operation of the torque sensor 9 are not different from the conventional one.

Here, an ECU storage unit for storing the ECU 11
12 is formed as follows. In the mount forming portion 8b of the housing 8 of the gear box portion 2, a space A having a relatively large area as compared with the depth is defined on the side opposite to the mount portion 23 across the steering shaft 4. The ECU 11 is stored in the space A.

The upper opening of the space A is covered by a cover 15. The cover 15 is liquid-tightly fixed to a cover mounting surface around the opening of the space A via a seal mechanism (O-ring) 16.

The space A has a substantially rectangular cross section in plan view, and its longer side is the torque sensor housing portion 8a.
1 to the left end flange 14 of the housing 8 in FIG. The flange 14 is formed at the end of the mount forming portion 8b and forms a connection with the yoke 13 of the electric motor 5. In this way, the space A and the cover 15 form the ECU storage unit 12.

A passage 18 for a wiring (harness) 17 connecting the ECU 11 and the electric motor 5 is formed through a portion of the wall surrounding the space A where the flange 14 faces the space A. ing. This passage 18 is provided with the electric motor 5
Of the brush holder 21 formed in the brush holder 21,
A wiring 17 extends from the ECU storage section 12 to the electric motor section 3 through these passages 18 and 22.

A passage 20 for a wiring (harness) 19 connecting the ECU 11 and the torque sensor 9 is provided at a portion where the partition wall 26 connecting the torque sensor housing portion 8a and the mount portion forming portion 8b faces the space A. The partition 26 is formed so as to penetrate therethrough.

The other end of the passage 20 is opened at a dividing surface which divides the torque sensor accommodating portion 8a into a top cover (upper half) 24 and another portion (lower half) 25. Further, it communicates with the accommodation space of the torque sensor 9. These passages 18, 20, 22 are respectively formed by machining.

In FIG. 2, reference numeral 31 denotes a coupler for input / output of an external signal (input of a vehicle speed signal, output of a signal at the time of fail-safe to the vehicle-side ECU), and reference numeral 32 denotes a power supply coupler.

Since the first embodiment is configured as described above, the following effects can be obtained. Gearbox section 2 in electric power steering apparatus 1
The ECU 8 is mounted in the mount forming portion 8b of the housing 8 of FIG.
A space A for accommodating the space 11 is provided, and a passage 18 for a wiring 17 connecting the ECU 11 and the electric motor 5 is formed through a portion of the wall surrounding the space A where the flange 14 faces the space A. Have been. Further, a partition (wall) 26 connecting the torque sensor housing portion 8a and the steering shaft housing portion 8b faces the space A, and is provided with an ECU.
A passage 20 for a wiring 19 connecting the torque sensor 9 to the torque sensor 9 is formed through.

As a result, the connection between the ECU 11 and the torque sensor 9 and the connection between the ECU 11 and the electric motor 5 are not exposed to the outside, and the housing 8 of the gear box 2 is not exposed.
The seal mechanism is not required for these connection parts because they are housed inside, and the seal mechanism 16 has to be applied only to the portion of the ECU storage unit 12 to which the cover 15 is attached, which simplifies the seal mechanism. Therefore, the joining reliability is also improved. In addition, the cost can be reduced.

Further, since the connection wirings 17 and 19 are made to pass through the internal passages 18 and 20 of the housing 8 of the gear box portion 2, the connection wirings 17 and 19 are shielded from the outside and are less affected by noise. The noise resistance of 17, 19 can be improved.

Further, the housing 8 of the gear box 2
The space between the torque sensor accommodating portion 8a and the electric motor section 3 can be effectively used to secure a space for storing the ECU 11. In addition, the wirings 17 and 19 for connecting the ECU 11 and the electric motor 5 and connecting the ECU 11 and the torque sensor 9 can be reduced to the maximum, and the cost can be reduced in this respect.

Next, one embodiment (Embodiment 2) of the invention described in claims 3 and 4 of the present application shown in FIGS. 4 and 5 will be described. FIG. 4 is a vertical cross-sectional view of a gear box portion of an electric power steering device to which the ECU installation structure according to the second embodiment is applied, and FIG. 4 is a plan view of a lower half part of a split surface B of a torque sensor accommodating portion of a housing of a gear box portion of FIG. Note that parts corresponding to the first embodiment are denoted by the same reference numerals.

In the second embodiment, as shown in FIG. 4, the space A for storing the ECU 11 is the torque sensor housing portion 8a of the housing 8 of the gear box portion 2.
And a portion below the torque sensor 9.

The ECU stored in the space A
As shown in FIGS. 4 and 5, a cast-out hole 28 is formed in a partition wall 27 separating the torque sensor 9 from the ECU 11, and a wire connecting the ECU 11 and the torque sensor 9 is formed. It is a passage for 19.

The partition wall 27 forms the top wall of the lower half portion 25 of the torque sensor housing portion 8a divided by the split surface B, and is formed to be relatively thick. Although not shown, the upper end of the steering output shaft and the lower part of the torque sensor 9 are accommodated respectively.

Therefore, the space A is actually provided as a space in the lower half 25 of the torque sensor housing portion 8a of the housing 8. This space is a bent space extending downward from the side of the steering shaft 4, and has a rectangular opening on the side of the steering shaft 4, and a cover 15 is provided with a seal mechanism (not shown) in this opening. )
Is applied in a liquid-tight manner.

In the space on the side of the steering shaft 4 in the lower half 25, a steering output shaft (not shown) and the steering shaft 4 are operatively connected via a mesh between a pinion of the steering output shaft and a rack 4a of the steering shaft 4. At a location, the space is formed along both sides of the steering output shaft (both sides as viewed in the axial direction of the steering shaft 4). In this way, the space A and the cover 15 form the ECU storage unit 12.

The body wall of the mount portion forming portion 8b of the housing 8 of the gear box portion 2 is provided with
A passage 29 for the wiring 17 that connects the ECU 11 and an electric motor (not shown) is formed to penetrate therethrough. The passage 29 communicates with passages (not shown) formed in the brush holder of the electric motor.
To the motor unit 3. The passage 29 is formed by machining, but may be formed by casting.

Reference numeral 31 denotes an input / output coupler for external signals, and reference numeral 32 denotes a power supply coupler. The second embodiment is different from the first embodiment in the above points, but there is no difference in other points, so that the detailed description is omitted.

Since the second embodiment is configured as described above, the following effects can be obtained. EC
The space A for storing U11 is provided in the torque sensor housing portion 8a of the housing 8 of the gear box portion 2.

As a result, the connection between the ECU 11 and the torque sensor 9 and the connection between the ECU 11 and the electric motor 5 are not exposed to the outside and the housing 8 of the gear box 2 is not exposed.
The seal mechanism at these connection portions is not required because the seal mechanism is housed in the ECU housing 12.
It is only necessary to apply 15 to the part to be adhered,
The sealing mechanism is simplified and the joining reliability is improved. In addition, the cost can be reduced.

The connection wires 19 and 17 are connected to the gear box 2
By passing through the internal passages (cast holes 28 and passages 29) of the housing 8, it is shielded from the outside, so that it is less affected by noise and the noise resistance of the connection wiring is improved.

Further, since neither the ECU storage part nor the coupler connection part is arranged between the torque sensor housing part 8a and the motor part 3, the motor part 3 can be arranged closer to the torque sensor housing part 8a side. (See FIG. 6), and the size and weight of the electric power steering apparatus 1 can be reduced. In addition, the arrangement / formation positions of the electric motor unit 3 and the mount unit 23 can be freely selected, and the degree of freedom in layout is improved.

The space A for storing the ECU 11 is:
A partition wall (the top wall of the lower half 25 of the torque sensor housing portion 8a) that is provided within the torque sensor housing portion 8a of the housing 8 of the gear box portion 2 and below the torque sensor 9 and separates the ECU 11 from the torque sensor 9 ) 27,
A cast-out hole 28 is formed, and this cast-out hole 28 is a passage for the wiring 19 connecting the ECU 11 and the torque sensor 9.

As a result, a space A for storing the ECU 11 can be secured by effectively utilizing the empty space below the torque sensor 9 and beside and below the steering shaft 4.

In particular, regarding the empty space on the side of the steering shaft 4, both sides of the steering output shaft are provided at a place where the steering output shaft (not shown) and the steering shaft 4 are operatively connected via the meshing of the gears by the pinion and the rack 4a. Since there is an empty space on the other side (on both sides as viewed in the axial direction of the steering shaft 4), this empty space can be used effectively.

Further, since it is not necessary to form a passage for passing the wiring 19 connecting the ECU 11 and the torque sensor 9 in the partition wall 27 by machining, the cost can be further reduced. In addition, the size of the passage can be freely selected.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an electric power steering apparatus to which an ECU installation structure according to an embodiment (Embodiment 1) of the invention described in claims 1 and 2 of the present application is applied. It is the figure which showed the part from the side view.

FIG. 2 is a plan view of the gear box portion of FIG.
FIG. 4 is a plan view of a portion below a split surface of a torque sensor housing portion of a housing with a cover of a U installation portion removed.

FIG. 3 is an enlarged view of a portion surrounded by a dashed line in FIG. 1;

FIG. 4 is a longitudinal sectional view of a gear box portion of an electric power steering apparatus to which an ECU installation structure according to one embodiment (Embodiment 2) of the invention described in claims 3 and 4 of the present application is applied; It is the figure which showed a part and side view.

5 is a plan view of a lower half portion of a split surface B of a torque sensor accommodating portion of a housing of the gear box portion in FIG. 4;

FIG. 6 is a diagram showing a modification of the electric power steering device of FIG. 4;

FIG. 7 is a diagram showing a conventional example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Electric power steering device, 2 ... Gear box part, 3 ... Electric motor part, 4 ... Steering shaft (rack shaft), 4a ... Rack, 5 ... Electric motor, 6 ... Hollow shaft, 7 ... Ball screw, 8 ... Housing, 8a: Torque sensor accommodating portion, 8b: Mount portion forming portion, 9: Torque sensor, 10: Steering input shaft, 11: ECU (electronic control unit), 12: ECU storage portion, 13: Yoke, 14: Flange, 15 ... Cover, 16… Seal mechanism (O-ring), 17…
Wiring, 18 passage, 19 wiring, 20 passage, 21 brush holder, 22 passage, 23 mounting portion, 24 top cover (upper half), 25 lower half, 26 partition, 27 … Wall (top wall), 28…
Cast-out hole, 29 ... passage, 31 ... coupler for external signal input / output,
32: Power supply coupler, A: Space, B: Split face.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Yoshinori Takeuchi 112-1 Hagadai, Haga-cho, Haga-gun, Tochigi F-term in Showa Tochigi Development Center Co., Ltd. 3D033 CA02 CA04 CA16 CA27 CA28

Claims (4)

[Claims] A steering shaft connected to wheels via a tie rod, a gear box section for inputting a steering force from a steering wheel, and an electric motor section for inputting a steering assist force from an electric motor, respectively; An installation structure of an ECU in an electric power steering device in which a torque sensor for detecting a steering torque is provided in the gear box portion, wherein a space for storing the ECU is provided in a housing of the gear box portion. The EC is provided on a wall of the housing surrounding the space.
An installation structure of an ECU in an electric power steering device, wherein a wiring passage connecting U and the torque sensor and a wiring passage connecting the ECU and the electric motor are respectively formed through. 2. The housing of the gear box portion includes a torque sensor housing portion for housing the torque sensor, and a mount portion formation extending from the torque sensor housing portion toward the electric motor portion and having a mount portion formed outside. The ECU installation structure in the electric power steering apparatus according to claim 1, wherein the space is provided in the mount portion forming portion. 3. The housing of the gear box portion includes a torque sensor housing portion that houses the torque sensor, and a mount portion formation that extends from the torque sensor housing portion in the direction of the electric motor portion and has a mount portion formed outside. The installation structure of an ECU in the electric power steering device according to claim 1, wherein the space is provided in the torque sensor accommodating portion. 4. The space is provided below the torque sensor, a cast hole is formed in a partition wall separating the ECU and the torque sensor, and the cast hole is formed between the ECU and the torque sensor. 4. A wiring path for connecting the two.
An installation structure of an ECU in the electric power steering device described in the above.