JP4455445B2 - Vehicle power steering device - Google Patents

Description

  The present invention relates to a power steering device for a vehicle.

As one means for reducing the driving operation of an automobile, there is a so-called electric power steering device that performs power assist of a steering force by driving an electric motor.
In this electric power steering apparatus, an input motor connected to a steering shaft and an output shaft with a worm wheel attached in the middle are connected by a torsion bar which is a strain generating portion, and an electric motor having a worm gear attached thereto is provided. Driving based on the torsional strain of the torsion bar and transmitting the rotational force of the electric motor to the worm wheel meshed with the worm gear, the steering force is assisted.

In addition, the torsion bar interposed between the input shaft and the output shaft is a small-diameter shaft to generate torsional strain. Therefore, in order to receive a load in the thrust direction, a separate thrust receiver It is necessary to provide.
The thrust bearing of the steering shaft in the conventional electric power steering apparatus is performed by a thrust bearing provided at the upper part of the column (see, for example, Patent Document 1).

JP 2000-159043 A (first page, FIG. 1)

  In performing the thrust receiving described above, it is desired to cope with the thrust load with a simple configuration without increasing the number of parts. However, the conventional electric power steering apparatus described above has a steering shaft and an input shaft of a torque sensor. Since it is connected via a universal joint, the column is supported by an upper bracket arranged above the torque sensor, and the thrust bearing provided at the top of the supported column is used, the number of parts is large and the size is reduced. It was a difficult structure.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a vehicle power steering device that can prevent a thrust load applied to a torsion bar while facilitating miniaturization with a simple configuration with a reduced number of parts.

In order to achieve the above technical problem, the power steering apparatus for a vehicle according to the present invention employs the following technical means.
In other words, the electric power steering apparatus according to the first aspect includes an input shaft that is disposed in the vicinity of the steering wheel (11) and is coupled to a steering shaft that is connected to the steering wheel, and a steering force according to rotation of the steering shaft. In a power steering device for a short small vehicle in front of the vehicle body , the steering shaft is connected to an output shaft for transmitting the power to a front tire portion connected to the output shaft via a universal joint. A stopper fixed to the shaft; a connecting member integrally provided at a lower portion of the stopper; connecting the steering shaft and the input shaft; a sensor housing through which the steering shaft is inserted and covering the torque sensor; and the sensor protruding from the upper inner wall of the housing and abuts against the stopper top Wherein a stopper receiving portion ing from wall-like member for preventing upward movement of the steering shaft, a cylindrical housing provided so as to be connected to the upper end of the sensor housing, the cylindrical housing stepped shape formed at the upper end portion of the A bearing in which the steering shaft is pivotally attached, a hole retaining ring fitted to the upper end of the cylindrical housing so as to abut on the outer side of the outer ring of the bearing, A shaft retaining ring that is fitted to the steering shaft so as to be in contact with the outer side of the inner ring of the bearing and prevents downward movement of the steering shaft, and the steering shaft is positioned near the steering wheel. The two points are supported by the stopper receiving portion and the retaining ring for the shaft .
A power steering device for a vehicle according to a second aspect is the power steering device for a vehicle according to the first aspect , wherein the stopper is provided on a connection member that holds an outer periphery of the steering shaft inside the sensor housing, and the connection member is disposed on the sensor housing. A working hole for operation is provided.
According to a third aspect of the present invention, there is provided the vehicle power steering apparatus according to the first or second aspect, wherein the sensor housing is formed so as to be gradually reduced in diameter toward an upper portion .

  According to the first aspect of the present invention, the stopper is provided on the steering shaft, the stopper receiving portion is provided in the sensor housing that covers the torque sensor, and the stopper receiving portion is in contact with the stopper so that the steering shaft in the thrust direction is provided. Since the movement is suppressed, the power steering device for a vehicle can reduce the number of parts and reduce the size, and can prevent the thrust load on the torsion bar and can easily couple the steering shaft and the torque sensor. Can provide.

  According to the second aspect, since the wall-like member protruding from the inner wall of the sensor housing is used as the stopper receiving portion, it is possible to suppress the movement of the steering shaft in the thrust direction with a simple structure without increasing the number of parts. it can.

  According to the third aspect, even when the torque sensor and the sensor housing are connected, the steering shaft and the input shaft can be finely adjusted through the work hole, so that workability can be improved.

  Next, an embodiment of a power steering device for a vehicle according to the present invention will be described. FIG. 1 shows an example of a power steering device for a vehicle according to the present invention incorporated in a small multipurpose vehicle (MUV).

  As shown in FIG. 1, the power steering device A for a vehicle according to the present embodiment includes a steering portion 1, a sensor housing 2, a support fitting 3, and a torque sensor 4.

  As shown in FIG. 2, the steering unit 1 has a steering wheel 11 for a driver to steer and an insertion hole 122 connected to the steering wheel 11 via a pin 124 and communicated with a counterbore hole 121. The bracket 12 provided in the portion and the rear portion is inserted into the insertion hole 122 and the shaft retaining ring 123 is fitted so as to contact the bottom surface of the bracket 12, and the screw portion 131 protruding into the counterbore hole 121 is attached to the nut 14 and a steering shaft 13 in which the bracket 12 is sandwiched between a shaft retaining ring 123 and a nut 14.

A stopper 132 protrudes and is fixed to the middle portion of the steering shaft 13. As shown in FIG. 4, a fitting hole 135 containing a slot 134 is provided at the lower portion of the stopper 132, and a bolt 136 is screwed in a direction orthogonal to the slot 134 to shrink the fitting hole 135. A block-shaped connecting member 133 formed to have a diameter is integrally formed with the stopper 132 by welding or the like.
The steering shaft 13 and the input shaft 41 described later are inserted into a fitting hole 135 provided in the connection member 133 and are coupled by screwing a bolt 136.

  The sensor housing 2 has a sensor cover portion 21 that covers the torque sensor 4, a cover fixing portion 22 that is formed so as to protrude from the lower end portion of the sensor cover portion 21 and is connected to a conductive case 5 described later, and is opened in the middle. The working hole 23, the stopper receiving portion 24 that receives the above-described stopper 132, the support portion 25 that rotatably supports the steering shaft 13, and the protrusion 26 that is supported by the support fitting 3 described later.

  That is, the sensor housing 2 is stepped so as to be gradually reduced in diameter toward the upper portion, and the conductive case 5 and the cover fixing portion 22 are fastened with the bolts 27 so as to be integrated with the conductive case 5 described later. It is a substantially cylindrical member attached. A support portion 25 that supports a cylindrical housing 250 on which the steering shaft 13 is pivotally attached is provided at the upper end portion of the sensor housing 2.

A protrusion 26 is integrally formed on the upper surface (center in FIG. 3) of the sensor housing 2. The protrusion 26 is formed with a boss 28a extending in the vehicle width direction. Further, the bosses 28b and 28c are provided on the left and right side surfaces (left and right direction in FIG. 3) of the sensor housing 2 so as not to overlap with the bosses 28a as viewed from the side.
In addition, a work hole 23 is provided on the lower surface of the sensor housing 2 through which a bolt 136 screwed to the connection member 133 can be inserted and tightened.

  A stopper receiving portion 24 made of a wall-like member is formed through the upper inner wall of the sensor housing 2 so that the steering shaft 13 can be inserted therethrough and protrudes perpendicularly to the steering shaft 13. In the sensor housing 2, the stopper 132 is disposed in contact with the stopper receiving portion 24, thereby preventing the steering shaft 13 from moving in the thrust direction, particularly in the upward direction (thrust in one direction of the steering shaft 13). Receive).

  A bearing 251 is fitted in a stepped hole formed in the upper end portion of the cylindrical housing 250 that is connected to the upper end portion of the sensor housing 2, and the hole retaining ring 252 includes a bearing 251 outer ring. The bearing 251 is fixed to the upper end portion of the cylindrical housing 250 by being fitted to the upper end portion of the cylindrical housing 250 so as to be in contact with the outside of the cylindrical housing 250. The cylindrical housing 250 may be connected to the upper end of the sensor housing 2 by welding, press-fitting, bolting, or the like, or formed on the outer wall of the cylindrical housing 250 and the inner wall of the sensor housing 2. It may be connected by screwing of the screw threads.

  On the other hand, a shaft retaining ring 137 that is a thrust receiver in the other direction is fitted to the steering shaft 13, and this shaft retaining ring 137 is in contact with the outer side of the inner ring of the bearing 251. By being disposed (provided in the cylindrical housing 250 axially outward from the bearing 251), the steering shaft 13 is inhibited from moving in the thrust direction, particularly in the downward direction (the other direction of the steering shaft 13). Receive thrust).

  In this way, the steering shaft 13 is supported at two points by suppressing the movement of the steering shaft 13 in the thrust direction by the stopper receiving portion 24 and the shaft retaining ring 137 provided separately from the stopper receiving portion 24. Thus, the steering shaft 13 can be favorably supported. In addition, since the position where the steering shaft 13 is supported at two points is in the vicinity of the steering wheel 11, the steering shaft 13 is more favorably supported.

  The support fitting 3 is a band plate member that is bent and formed into a substantially convex shape with an opening at the bottom and is welded to a cross member B that is one of the vehicle frames. In the support metal 3, a boss 28 a provided on the protrusion 26 of the sensor housing 2 and an upper part of the support metal 3 covering the outside of the boss 28 a are connected by a parallel pin 31. The left and right bosses 28b, 28c projecting from the sensor housing 2 and the lower part of the support fitting 3 that covers the outside of the bosses 28b, 28c are screwed together. A conduction case 5, a torque sensor 4 and an electric motor 6 described later, which are integrally attached to the vehicle 2, are supported by the vehicle frame.

  The torque sensor 4 has an input shaft 41 connected to the steering shaft 13 by being inserted into the fitting hole 135 of the connecting member 133 and closing the bolt 136, and a worm wheel (not shown) attached to the middle portion. The output shaft 42, a torsion bar 43 that is interposed between the input shaft 41 and the output shaft 42 and serves as a strain generating portion, and a sensor (not shown) that detects torsional strain of the torsion bar 43. It is comprised and is comprised by the conductive case 5 inside.

  As described above, the torque sensor 4 is covered with the sensor housing 2, and the sensor housing 2 is located near the steering wheel 11 via the support fitting 3 welded to the cross member B as shown in FIG. 1. Supported by the car body.

The conductive case 5 has a wall surface that is connected to the cover fixing portion 22 of the sensor housing 2 by bolts 27 in the middle, and an electric motor 6 to which a worm gear (not shown) meshed with a worm wheel is attached. It is formed in the required shape that is screwed onto.
The electric motor 6, the worm gear, and the worm wheel are included to constitute a gear unit.

  The power steering apparatus A for a vehicle according to the present embodiment configured as described above drives the electric motor 6 based on the torsional distortion of the torsion bar 43 and transmits the driving force to the worm wheel meshed with the worm gear. As a result, the driving force is transmitted to the front tire portion connected to the output shaft 42 via the universal joint 7 to assist the steering force.

  Further, the power steering apparatus A for a vehicle according to the present embodiment is configured to protrude from the upper inner wall in the sensor housing 2 even when the steering wheel 11 is biased in the thrust direction (particularly upward). Furthermore, the thrust 132 applied to the torsion bar 43 is prevented by the stopper 132 projecting from the steering shaft 13 being in contact therewith.

  Further, the sensor housing 2 of the vehicle power steering apparatus A is provided in the vicinity of the steering wheel 11, and the steering shaft 13 is pivotally attached by a bearing 251 provided at the upper end portion of the sensor housing 2. Since the distance is reduced as much as possible, it is not necessary to provide a bearing above the power steering apparatus A of the vehicle, and the number of parts can be reduced.

  Although the vehicle power steering apparatus A according to the present embodiment has been described above, the above-described embodiment shows an example of a preferred embodiment of the present invention, and the present invention is not limited thereto. However, various modifications can be made without departing from the scope of the invention.

The stopper 132 may continuously cover the outer periphery of the steering shaft 13 or may be discontinuous. Further, the stopper receiving portion 24 may continuously protrude inside the sensor housing 2. However, the stopper 132 and the stopper receiving part 24 are always in contact.
The present invention is particularly effective for small vehicles such as MUV with a short front of the vehicle body.

1 is a partially cutaway side view and an enlarged view of a cutout portion in a state where a power steering device for a vehicle according to an embodiment is incorporated in a small multipurpose vehicle (MUV). 1 is a partially cutaway side view of a power steering device for a vehicle according to an embodiment. It is an arrow view (front view) of the Z direction in FIG. It is a longitudinal cross-sectional view of the X part in FIG. FIG. 5 is a transverse sectional view taken along line X1-X1 in FIG. FIG. 6 is a transverse sectional view taken along line X2-X2 in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS A ... Vehicle power steering device, 1 ... Steering part, 11 ... Steering wheel, 12 ... Bracket, 13 ... Steering shaft, 131 ... Screw part, 132 ... Stopper, 133 ... Connection member, 134 ... Slot, 135 ... Fitting Hole: 136 ... Bolt, 137 ... Retaining ring for shaft, 14 ... Nuts, 2 ... Sensor housing, 21 ... Sensor cover part, 22 ... Cover fixing part, 23 ... Working hole, 24 ... Stopper receiving part, 25 ... Support part, 250 ... cylindrical housing, 251 ... bearing, 252 ... retaining ring for hole, 26 ... projection, 27 ... bolt, 28a, 28b, 28c ... boss, 3 ... support bracket, 31 ... parallel pin, 4 ... torque sensor, 41 ... Input shaft, 42 ... Output shaft, 43 ... Torsion bar, 5 ... Conduction case, 6 ... Electric motor, 7 ... Universal joint, B ... Cross member

Claims (3)

An input shaft that is disposed in the vicinity of the steering wheel and is coupled to a steering shaft that is connected to the steering wheel, and an output shaft that transmits a steering force according to the rotation of the steering shaft are connected via a torque sensor ,
In a power steering device for a short small vehicle in front of a vehicle body that transmits a driving force to a front tire portion connected to the output shaft via a universal joint ,
A stopper fixed to the steering shaft ;
A connecting member integrally provided at the lower portion of the stopper and connecting the steering shaft and the input shaft;
A sensor housing through which the steering shaft is inserted and covering the torque sensor ;
And the sensor protruding from the upper inner wall of the housing to abut against the stopper top, the stopper receiving portion ing from wall-like member for preventing upward movement of the steering shaft,
A cylindrical housing connected to the upper end of the sensor housing;
A bearing that is fitted in a stepped hole formed in the upper end of the cylindrical housing, and on which the steering shaft is pivotally mounted;
A retaining ring for a hole fitted to the upper end of the cylindrical housing so as to abut on the outer side of the outer ring of the bearing;
A shaft retaining ring that is fitted and arranged on the steering shaft so as to be in contact with the outer side of the inner ring of the bearing, and suppresses the downward movement of the steering shaft;
A power steering device for a vehicle, wherein the steering shaft is supported at two points by the stopper receiving portion and the shaft retaining ring at a position near the steering wheel . The stopper is provided on a connection member that holds an outer periphery of the steering shaft inside the sensor housing,
The electric power steering apparatus according to claim 1 , wherein the sensor housing is provided with a work hole for operating the connection member. 3. The electric power steering apparatus according to claim 1 , wherein the sensor housing is formed so as to be gradually reduced in diameter toward an upper part .

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