JP2001108542A - Torque sensor unit for electric power steering device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a reliable torque sensor unit for an electric power steering device allowing the improvement of assembling workability. SOLUTION: This torque sensor unit has a housing space 21 for housing an electrical or electronic component; a housing 1 formed with a second opening 25 making the housing space 21 communicate with the outside; a connector 30 blocking off the second opening 25; and an elastic shim 40 closely sealing between the second opening 25 and the connector 30. Accordingly, only sandwiching the elastic shim 40 of a predetermined shape between the housing 1 and the connector 30 can fill a gap between the periphery of the second opening 25 and the connector 30 to improve workability and effectively prevent the penetration of water. Even if the connector 30 has a shape allowing the projection of a metal bush 35 from a flange part 31B, the elastic shim 40 can closely seal between the flange part 31B and the housing 1 to prevent the penetration of water into between them.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a torque sensor unit, and more particularly, to a torque sensor unit that can be suitably used for an electric power steering device or the like.

[0002]

2. Description of the Related Art An example of this type of torque sensor is disclosed in, for example, Japanese Patent Application Laid-Open No. 8-122175 previously proposed by the present applicant. The torque sensor described in this publication includes a main body having a sensor portion, a metal plate directly fixed on the main body, a substrate fixed on the metal plate but not directly fixed to the main body, and a substrate provided on the substrate. And a detection circuit connected to the sensor unit. The detection circuit is disposed only on one surface of the substrate, and the other surface of the substrate that is in contact with the metal plate is entirely grounded. According to such a configuration, since all the electronic components are mounted on one surface of the substrate,
It has various advantages such as an improved shielding effect against noise and an improved assemblability.

[0003]

By the way, in the electric power steering apparatus, the torque sensor is housed in a torque sensor unit including a housing and the like, but is installed at a lower part of the vehicle body where rainwater or the like is likely to splash. Often. However, it has been found that such a conventional torque sensor unit has a problem with waterproofness. Such a problem will be described.
In the torque sensor unit, the mating portion between the aluminum housing for housing electronic parts such as circuits and the connector is sealed by applying a hardening type elastic sealing material (for example, a room temperature hardening type silicon solvent) or the like. Here, the connector is formed by integrally molding the metal bush for screwing and the resin body, but in such a connector, the end face of the metal bush is protruded from the resin body, so that the connector at the time of screwing is formed. The seat surface strength is secured.

However, by protruding the end face of the metal bush from the resin body in this way, a slight gap is created between the aluminum housing surface and the resin body,
Moisture may enter from outside through such a gap. Moisture that has entered the gaps freezes during severe cold and expands in volume, which may damage the resin body.

On the other hand, since the shape of the aluminum housing on which the elastic sealing material is to be applied is complicated, when applying the elastic sealing material to the entire periphery of the mating surface with the connector, it is necessary to carefully perform the application work so as not to protrude. Therefore, there is a problem that it takes time and is difficult to work.

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems of the prior art, and has as its object to provide a torque sensor unit of an electric power steering device which ensures reliability and improves workability during assembly. I do.

[0007]

In order to achieve the above object, a torque sensor unit of an electric power steering apparatus according to the present invention includes a housing space for housing electric or electronic components, and a housing space for housing the electric or electronic component. A housing having an opening communicating therewith, a connector member for shielding the opening, and sealing means for sealing between the opening and the connector member, wherein the sealing means has a plate-like elasticity. It is characterized by being a body.

[0008]

According to the torque sensor unit of the electric power steering device according to the present invention, there is provided a housing having an accommodation space for accommodating electric or electronic components, and an opening for communicating the accommodation space with the outside. A connector member for shielding the opening, and a sealing means for sealing between the opening and the connector member, wherein the sealing means,
Since it is a plate-shaped elastic body, simply sandwiching the plate-shaped elastic body whose shape has already been determined between the housing and the connector member allows a gap between the housing and the connector member at the open end. Can be filled, the workability is excellent, and the intrusion of moisture can be effectively prevented. Further, for example, even if the connector member has a shape in which a metal bush protrudes from the main body, the space between the main body and the housing can be sealed with the plate-shaped elastic body, so that moisture may enter between the two. Can be prevented. The plate-like elastic body may be a shim such as a coating oil sheet, a cork sheet, a packing, or rubber, but is not limited thereto. Inside the plate-shaped elastic body, another sealing means such as an O-ring for preventing foreign substances from entering the housing can be provided.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. FIGS. 1 to 7 show an embodiment of the present invention. In this embodiment, a torque sensor unit according to the present invention is applied to an electric power steering device of a vehicle. 1 is a front view showing the entire steering system, FIG. 2 is a longitudinal sectional view showing a main part (electric power steering device) of the steering system, and FIG. 3 is a diagram showing the configuration of FIG. 4 is a cross-sectional view of the configuration of FIG. 3 taken along the line IV-IV and viewed in the direction of the arrow, and FIG. 5 is a cross-sectional view of the configuration of FIG.
FIG. 6 is a cross-sectional view of the configuration of FIG. 5 taken along the line VI-VI and viewed in the direction of the arrow. FIG. 7 is a perspective view of the elastic shim. FIG. 4 is a view similar to FIG. 3 with a connector described below removed.

In FIG. 1, a rack shaft 6 (not shown) extends horizontally in the housing 1 (see FIG. 2). Tie rods 51 and 52 are connected to both ends of the rack shaft 6,
The tie rods 51 and 52 are connected to a steering mechanism (not shown). Although not shown, an electric power steering device is arranged at the center of the housing 1. Less than,
The configuration of the electric power steering device will be described in detail.

In FIG. 2, an input shaft 2 and an output shaft 3 connected via a torsion bar 4 are provided in a housing 1 comprising an upper housing 1A and a lower housing 1B.
Are rotatably supported by bearings 5a, 5b and 5c. The input shaft 2, the output shaft 3 and the torsion bar 4 are coaxially arranged, and the upper end side of the torsion bar 4 is pin-coupled to the input shaft 2 at a position where the torsion bar 4 is deeply inserted into the input shaft 2 to rotate in the rotation direction It is united with,
The lower end of the torsion bar 4 is spline-coupled to the output shaft 3 so as to be integrated in the rotation direction.

A steering wheel is integrally mounted on the upper end of the input shaft 2 via a universal joint (not shown), a steering shaft, and the like in a rotational direction.
A pinion 3a is formed at the lower end of the output shaft 3,
The pinion 3a meshes with the rack shaft 6. The pinion 3a and the rack shaft 6 constitute a known rack and pinion type steering device.
The steering force generated by the driver steering the steering wheel causes a steering mechanism (not shown) to operate via the input shaft 2, the torsion bar 4, the output shaft 3 and the rack and pinion type steering device, thereby steering the wheels. Will do.

Further, a worm wheel 7 which coaxially rotates with the output shaft 3 is externally fitted to the output shaft 3, and a resin engagement portion 7a of the worm wheel 7 and an electric motor 8
And the worm 8b formed on the outer peripheral surface of the output shaft 8a. Therefore, the torque of the electric motor 8 is transmitted to the output shaft 3 via the output shaft 8a, the worm 8b and the worm wheel 7, and the torque and the direction of rotation of the electric motor 8 are appropriately adjusted. By controlling, an appropriate steering assist torque can be applied to the output shaft 3.

The upper housing 1A mainly surrounding the input shaft 2 includes a sensor housing space 20 for housing a sensor 10 whose state changes according to the torque generated in the steering system, And a board housing space 21 for housing a board (electronic component) 9 on which a circuit unit that receives an output and executes a predetermined process is formed. Note that the sensor housing space 20 is a substantially thick cylindrical space formed by a gap between the input shaft 2 and the upper housing 1A, and the substrate housing space 21 has a diameter of the sensor housing space 20. It is a substantially rectangular parallelepiped space formed so as to approach outward in the direction.

The configuration of the sensor unit 10 housed in the sensor unit housing space 20 is not particularly limited, and for example, the structure disclosed in Japanese Patent Application Laid-Open No. 8-240492 can be used. That is, in the embodiment of the present invention, the output shaft 3 is fixed so as to rotate integrally therewith,
A thin cylindrical member 11 made of a conductive and non-magnetic material (for example, aluminum) surrounding the outer peripheral surface of the input shaft 2;
A plurality of grooves 12 having a substantially rectangular cross section formed in the outer peripheral surface of the input shaft 2 surrounded by the cylindrical member 11 and extending in the axial direction.
And a plurality of cylindrical members 11 formed such that the degree of overlap with the groove 12 changes according to the direction and amount of twisting of the torsion bar 4 between the input shaft 2 and the output shaft 3 with twisting. A coil (not shown) and a coil unit 13 fixed to the upper housing 1A side and detecting the degree of overlap between the window of the cylindrical member 11 and the groove 12 of the input shaft 2 as a change in coil inductance. And the sensor unit 1
The end 13 a of each coil of the zero coil unit 13 is pulled out toward the substrate housing space 21 and inserted into a predetermined position of the substrate 9.

On the upper surface of the substrate 9, a steering assist torque is calculated based on the output of the sensor unit 10 supplied through the end 13a so that the steering torque generated in the steering system becomes an optimum value. A control signal is output to a drive circuit (not shown) of the electric motor 8 so that the steering assist torque is generated.

Further, as shown in FIG.
The first is used when incorporating the substrate 9 therein.
An opening 22 is formed. This first opening 22 is
A substantially rectangular opening slightly larger than the planar shape of the substrate 9, which is closed by fixing the cover 23 to the surface of the outer housing 1 </ b> A after the substrate 9 is accommodated. The cover 23 is a thin aluminum member, and a convex portion 23A is formed on the surface side of the cover 23 so as to be continuous along an edge portion of the first opening portion 22, and an upper housing of the convex portion 23A is formed. An endless seal member 23B is embedded on the back side facing the 1A side. The seal member 23 </ b> B is for preventing water or the like from entering the substrate housing space 21 via the first opening 22 after the cover 23 is fixed. Specifically, when the cover member 23B is fixed, the seal member 23B intervenes between the upper housing 1A and the cover 23 when the cover 23 is fixed. It comes into close contact with the edge to prevent water or the like from entering.

Further, one side surface of the substrate accommodating space 21 has a thicker portion 24 thicker than the other portions, and the thicker portion 24 has a circular second portion communicating with the substrate accommodating space 21. The opening 25 is opened independently of the first opening.

That is, the thick portion 24 is a block-shaped portion that is continuous with the side surface of the substrate accommodating space 21, and the circular second opening 25 is opened substantially at the center thereof.
The direction in which the center axis of the second opening 25 faces is a direction parallel to the long side of the first opening 22. Further, as can be seen from FIG. 8, the diameter of the second opening 25 is such that a part of the substrate 9 can be seen from the outside.

A connector member, that is, a connector 30 is fixed to the second opening 25. The connector 30 is a connector body 31 made of a conductive resin.
And the connector body 31 has the second opening 2
5, a flange 31B that contacts the surface of the thick portion 24, and a box 31C that rises from a surface of the flange 31B opposite to the cylinder 31A.
And is composed of Such a connector body 31 is
With the cylindrical portion 31A inserted into the second opening 25, two bolts 32 penetrating a metal bush 35 (FIG. 6) integrally molded with the flange portion 31B are screwed into the thick portion 24. Thereby, it is fixed to the upper housing 1A.

The connector main body 31 supports a plurality of (in this example, six) pins 33. These pins 3
Reference numeral 3 denotes an output for outputting the output of the circuit section on the substrate 9 to the outside. One end of the output section 3 is formed in a circular cross section and inserted into the end of the substrate 9 from the back side. Has become. The other end of the pin 33 has a rectangular cross section and extends to a position slightly inside the opening end of the box portion 31C. Each pin 33 is fixed to the bottom of the box portion 31C via a ring 34 made of synthetic rubber, which is an insulator.

It is desirable that the outer diameter of these rings 34 be as small as possible than the wavelength of the electromagnetic wave to be cut off. In the present embodiment, the dimensions are such that they are present only in positions deeper than substrate 9 in substrate accommodation space 21.

The portion 33A of each pin 33 supported by the connector body 31 via the ring 34 extends parallel to the central axis of the second opening 25. A portion 33B continuously bent at a right angle and extending toward the substrate 9 is formed at an end portion inside the space 21, and the tip of the portion 33B extending toward the substrate 9 is
It is inserted on the back side of the substrate 9.

The length of the portion 33B of each pin 33 is such that the tip of the portion 33B on the substrate 9 side is the connector body 3B.
The dimensions are such that they are located inside the outer peripheral surface of one cylindrical portion 31A. This is because when the connector 30 to which the pin 33 is fixed is fixed to the thick portion 24, the portion 33B bent at a right angle to the pin 33 can easily pass through the second opening 25, that is, This is for simplifying the work when fixing the connector 30.

A portion 33B of the pin 33 bent at a right angle.
As described above, the fixing position of the substrate 9 in the depth direction is set to a position where a part of the second opening 25 can be seen from the outside, as shown in FIG. The actual assembly procedure is as follows.
After that, the substrate 9 is fixed, and the cover 23 is fixed.

Further, between the periphery of the second opening 25 and the connector 30, an elastic shim 40, which is a plate-like elastic body, is sandwiched. As shown in FIGS.
Has a substantially rhombic thin plate shape equal to the flange portion of the connector 30, and has a cylindrical portion 31A of the connector 30 in the center.
Is formed, and holes 42 for inserting a metal bush 35 for guiding the bolt 32 are formed at both ends. After the connector 30 is fixed, the elastic shim 40 intervenes in a gap between the periphery of the second opening 25 and the connector 30 to eliminate a space into which water or the like intrudes, and to prevent problems such as freezing in severe cold. This is to prevent it. The O-ring 40a provided on the inner periphery of the entrance of the second opening 25 prevents foreign matter such as water from entering the housing 1A.

Next, the operation of the electric power steering apparatus according to this embodiment will be described. Assuming that the steering system is in a neutral state and the steering torque is zero,
No relative rotation occurs between the input shaft 2 and the output shaft 3. Therefore, no relative rotation occurs between the input shaft 2 and the cylindrical member 11.

On the other hand, when a steering wheel (not shown) is steered to generate a rotational force on the input shaft 2, the rotational force is transmitted to the output shaft 3 via the torsion bar 4. At this time, a resistance force is generated on the output shaft 3 in accordance with the steering theory and the frictional force between the road surface and the frictional force such as the meshing of the gears of the rack and pinion type steering device. , The output shaft 3 is delayed due to the twisting of the torsion bar 4, and the relative rotation also occurs between the input shaft 2 and the cylindrical member 11. The direction and amount of the relative rotation have given values according to the steering direction of the steering wheel and the generated steering torque.

As a result, since the inductance of the coil of the coil unit 13 is appropriately changed according to the direction and magnitude of the steering torque, the steering assist torque is reduced in the circuit on the substrate 9 to which the end 13a of the coil is connected. It is possible to execute arithmetic processing for determination.

As a result of the arithmetic processing in the circuit on the substrate 9,
A control signal is supplied to a drive circuit (not shown) via a pin 33, and a rotational force for generating a steering assist torque is generated in the electric motor 8, which is applied to the output shaft 3 via the worm 8b or the worm 7. The transmitted steering torque is applied to the output shaft 3, so that the burden of the steering force is reduced.

Further, in the present embodiment, the first opening 2
Since the second and second openings 25 are formed independently of each other, the respective openings can be easily sealed by the seal member 23B and the O-ring 40a, thereby preventing water or the like from entering from the outside. This can be more reliably prevented.

In particular, as shown in FIG. 6, the connector 30 has a metal bush 35 integrally molded with a resin flange 31B so that both ends of the metal bush 35 do not receive the fastening force of the bolt 32 at the flange 31B. Since it is formed so as to protrude from the flange 31B, the sealing performance becomes a problem.
On the other hand, according to the present embodiment, the elastic shim 40
Since the periphery of the second opening 25 and the connector 30 are sealed, there is no gap as in the case of applying a liquid hardening type sealing material as in the prior art. Since intrusion can be effectively prevented, breakage of the connector 30 due to icing can be prevented even in severe cold. At the time of assembly, as shown in FIG. 8, the elastic shim 40 conforming to the shape of the flange 31B is inserted into the second opening 2.
It is sufficient to incorporate the connector 30 in a state where the connector 30 is placed around the device 5, and a complicated application operation as in the related art is not required, so that the operation time can be reduced and the operation can be simplified. still,
The elastic shim 40 preferably has such a thickness that the tip of the metal bush 35 does not bottom on the housing 1A even if the elastic shim 40 is elastically deformed when the bolt 32 is fastened.

Further, as a result of forming the first opening 22 and the second opening 25 independently of each other, when the connector 30 is fixed, the portion 33B bent at a right angle of the pin 33 becomes the second opening.
Because it is necessary to pass through the quiet entrance 25, as described above,
The length of the part 33B is determined.
By determining the length dimension of the portion 33B in this manner, the national fixed position in the depth direction of the substrate 9 is a position that can be seen from the outside of the second opening 25.

For this reason, there is a concern that electromagnetic waves arriving from the outside through the second opening 25 may affect the circuit portion on the surface side of the substrate 9. 1 is made of iron, the cover 23 is made of aluminum, and the connector main body 31 is made of conductive resin. Therefore, each of the housing 1, the cover 23 and the connector main body 31 is made of an electromagnetic wave shielding material capable of shielding electromagnetic waves. It is formed by.

Accordingly, the substrate accommodation space 2 accommodating the substrate 9
In FIG. 1, the ring 34 is fixed at a position deeper than the position where the substrate 9 is accommodated. The effect on the circuit part fixed on the front side (both sides visible in FIG. 3) of Nin. 9 is substantially zero. Therefore, the possibility that the circuit on the substrate 9 malfunctions under the influence of the electromagnetic wave is extremely small.

If the portion 33B of the pin 33 bent at a right angle is lengthened so that its end is located further outside the inner peripheral surface of the second opening 25, the substrate 9 becomes It is also possible to fix to a position invisible from the outside of the part 25, so that the influence of the electromagnetic wave on the circuit on the substrate 9 can be extremely reduced only by forming the upper housing 1A and the cover 23 with an electromagnetic wave shielding material. It is. However, in such a configuration, when the connector 30 is fixed, the cylindrical portion 3B is obliquely oriented so that the pin 3B bent at a right angle passes through the second opening 25.
Work such as insertion of 1A is required, resulting in a reduction in workability during assembly.

On the other hand, with the configuration as in the present embodiment, the possibility that the electromagnetic wave affects the circuit can be reduced without such a decrease in workability. Further, in the present embodiment, the pin 33 is connected to the insulating ring 34.
Therefore, there is no short circuit between the pin 33 and the connector body 31 made of conductive resin.

As described above, the present invention has been described in detail with reference to the embodiments. However, the present invention should not be construed as being limited to the above-described embodiments, and may be appropriately modified within a range not to impair the gist of the present invention. Of course, it can be improved. For example, the elastic shim may be a shim such as, but not limited to, a coating oil sheet, a cork sheet, packing or rubber.

[0039]

According to the torque sensor unit of the electric power steering apparatus according to the present invention, a housing having a housing space for housing electric or electronic components and an opening communicating the housing space with the outside. And a connector member for shielding the opening, and sealing means for sealing between the opening and the connector member. Since the sealing means is a plate-like elastic body, the housing and the connector Between the members, only by sandwiching the plate-shaped elastic body whose shape is already determined, it is possible to fill the gap between the housing and the connector member at the open end, so that the workability is excellent, In addition, the intrusion of moisture can be effectively prevented. Further, for example, even if the connector member has a shape in which a metal bush protrudes from the main body, the space between the main body and the housing can be sealed with the plate-shaped elastic body, so that moisture may enter between the two. Can be prevented.

[Brief description of the drawings]

FIG. 1 is a front view showing the entire steering system.

FIG. 2 is a longitudinal sectional view showing a main part of a steering system.

FIG. 3 is a view of the configuration of FIG. 1 as viewed in the direction of arrow III.

FIG. 4 is a cross-sectional view of the configuration of FIG. 3 taken along line IV-IV and viewed in a direction indicated by an arrow.

FIG. 5 is a view of the configuration of FIG. 3 as viewed in the direction of arrow V.

FIG. 6 is a cross-sectional view of the configuration of FIG. 5 taken along line VI-VI and viewed in a direction indicated by an arrow.

FIG. 7 is a perspective view of an elastic shim.

FIG. 8 is a view similar to FIG. 3 with a connector to be described later removed.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Housing 1A Upper housing 1B Lower housing 9 Substrate 10 Sensor part 20 Sensor part accommodating space 21 Substrate accommodating space 22 First opening 23 Cover 25 Second opening 30 Connector 40 Elastic shim

Claims (1)

[Claims] 1. A housing having an accommodation space for accommodating an electric or electronic component, an opening communicating the accommodation space with the outside, a connector member for shielding the opening, the opening, and the connector A torque sensor unit for an electric power steering device, comprising: sealing means for sealing between members; and wherein the sealing means is a plate-shaped elastic body.