CN114194279A - Mounting structure and mounting method of steering gear box - Google Patents

Abstract

The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a mounting structure of a steering gear box and a mounting method thereof, which have a small difference in responsiveness in left and right steering. In order to solve the problem of the present invention, a mounting structure of a steering gear box is a mounting structure for mounting a gear box 52, which houses a rack shaft that is displaced in a vehicle width direction by a steering force, on a front subframe 3 of a vehicle body, wherein the gear box 52 is fixed to the front subframe 3 of the vehicle body by a left mounting portion 57L and a right mounting portion 57R provided at positions separated in an axial direction of the rack shaft, and a center mounting portion 57C provided between the left mounting portion 57L and the right mounting portion 57R in the axial direction. The center mounting portion 57C is fixed to the front subframe 3 via a mounting bush provided with a rubber member, and the left and right mounting portions 57L and 57R are fixed to the front subframe 3 more rigidly than the center mounting portion 57C.

Description

Mounting structure and mounting method of steering gear box

Technical Field

The invention relates to a mounting structure and a mounting method of a steering gear box. And more particularly, to a mounting structure and a mounting method for mounting a gear box of a steering apparatus on a vehicle body.

Background

The steering device is provided with: a pinion shaft that rotates in accordance with a steering operation of a steering wheel that is driven by a driver; a rack shaft that meshes with the pinion gear of the pinion shaft and is displaced along an axis thereof when the pinion shaft rotates; and a gear box for accommodating the rack shaft and the pinion. The gear box of the steering device is fixed to the vehicle body in a state where the axis of the rack shaft is parallel to the vehicle width direction.

Patent document 1 discloses an invention relating to a mounting structure for mounting an electric power steering apparatus to a vehicle body. In the electric power steering apparatus disclosed in patent document 1, the pinion shaft and the electric motor are supported on both sides along the axis of the gear box, and the gear box is coupled to the vehicle body at two positions, that is, a steering side mounting portion provided in the vicinity of a portion supporting the pinion shaft and a motor side mounting portion provided in the vicinity of a portion supporting the electric motor. In the mounting structure of patent document 1, the motor-side mounting portion is fixed to the vehicle body via a rubber bush, and the steering-side mounting portion is fixed to the vehicle body via a metal bush having a higher spring constant than the rubber bush. This can reduce the vibration sound of the electric motor while maintaining the steering responsiveness.

[ Prior Art document ]

(patent document)

Patent document 1: japanese patent laid-open No. 2014-84079

Disclosure of Invention

[ problems to be solved by the invention ]

However, according to the mounting structure of patent document 1, the displacement amount of the gear box when steering the tire on the motor side mounting portion elastically fixed to the vehicle body is larger than the displacement amount of the gear box when steering the tire on the steering side mounting portion rigidly fixed to the vehicle body. Therefore, when the tire is steered to the left side and the right side, a difference in responsiveness occurs, and the driver may feel uncomfortable. In addition, according to the mounting structure of patent document 1, since the steering-side mounting portion has a higher load sharing ratio than the motor-side mounting portion, it is necessary to design the metal bush mounting portion firmly, which may increase cost and weight.

The invention aims to provide a mounting structure of a steering gear box and a mounting method thereof, wherein the mounting structure has small difference of responsiveness in left and right steering.

[ means for solving problems ]

(1) A mounting structure of a steering gear box according to the present invention is a mounting structure for mounting a gear box (for example, a gear box 52 described later) that houses a rack shaft that is displaced in a vehicle width direction by a steering force on a vehicle body (for example, a front side frame 2L,2R and a front sub-frame 3 described later), the mounting structure being characterized in that: the gear case is fixed to the body by a first mounting portion (e.g., a left mounting portion 57L described later) and a second mounting portion (e.g., a right mounting portion 57R described later) provided at positions separated in the axial direction of the rack shaft, and a third mounting portion (e.g., a center mounting portion 57C described later) provided between the first mounting portion and the second mounting portion in the axial direction, the third mounting portion is fixed to the body via an elastic member (e.g., a rubber member 592 of a mounting bushing 59 described later), and the first mounting portion and the second mounting portion are fixed to the body more rigidly than the third mounting portion.

(2) In this case, it is preferable that the first attachment portion and the second attachment portion are fixed to the vehicle body without an elastic member.

(3) In this case, it is preferable that the pinion shaft (for example, a pinion shaft 51 described later) to which the steering force is input is engaged with the rack shaft at one side in the vehicle longitudinal direction, the first mounting portion and the second mounting portion are provided at the one side in the vehicle longitudinal direction with respect to the rack shaft, and the third mounting portion is provided at the other side in the vehicle longitudinal direction with respect to the rack shaft.

(4) In this case, it is preferable that the gear box is attached to a subframe (for example, a front subframe 3 described later) of the vehicle body, and the subframe includes: a first front-rear portion (e.g., a left front-rear portion 31L described later) and a second front-rear portion (e.g., a right front-rear portion 31R described later) that extend in the vehicle front-rear direction; and a connecting portion (for example, a connecting portion 32 described later) extending in the vehicle width direction and connecting the first front-rear portion and the second front-rear portion;

the first mounting portion is mounted on a first fixing portion (for example, a left seat surface 34L described later) provided on the first front and rear portion, the second mounting portion is mounted on a second fixing portion (for example, a right seat surface 34R described later) provided on the second front and rear portion, and the third mounting portion is mounted on a third fixing portion (for example, a center seat surface 34C described later) provided on the connecting portion.

(5) In this case, it is preferable that the gear box is attached to a subframe (for example, a front subframe 3 described later) of the vehicle body, and the subframe includes: a first fixing portion (for example, a left seat surface 34L described later) to which the first mounting portion is mounted; a second fixing portion (for example, a right seat surface 34R described later) to which the second mounting portion is mounted; a third fixing portion (for example, a center seating surface 34C described later) to which the third mounting portion is mounted; main fixing portions (e.g., a left bulging portion 35L and a right bulging portion 35R described later) attached to a main frame of the vehicle body; and a rib (for example, a left rib 33L and a right rib 33R described later) that connects the first attachment portion in a state of being attached to the first fixing portion or the second attachment portion in a state of being attached to the second fixing portion to the main fixing portion.

(6) The method for mounting a steering gear box of the present invention is a method for mounting a gear box of any one of (1) to (4) on a vehicle body, characterized in that: the first mounting portion and the second mounting portion are fixed to the vehicle body, and then the third mounting portion is fixed to the vehicle body.

(Effect of the invention)

(1) In the present invention, the first mounting portion and the second mounting portion provided at positions separated in the axial direction of the rack shaft are more rigidly fixed to the vehicle body than the third mounting portion, whereby a difference in the amount of displacement of the gear box relative to the vehicle body in the axial direction during left-right steering can be reduced, and even a difference in responsiveness during left-right steering can be reduced. In the present invention, the gear case is fixed to the vehicle body at three portions, namely, the first mounting portion, the second mounting portion, and the third mounting portion, whereby the rotation of the gear case relative to the vehicle body about the axis passing through the first mounting portion and the second mounting portion can be suppressed. Further, in the present invention, since the third mounting portion is provided between the first mounting portion and the second mounting portion in the axial direction, it is possible to reduce the influence of the difference in responsiveness at the time of left-right steering due to elastic fixation of the third mounting portion.

Further, due to variations in manufacturing of the gear box or the vehicle body, the mounting portion of the gear box may slightly overhang the seating surface of the vehicle body. In this case, if it is desired to fix the mounting portion of the gear housing to the seat surface of the vehicle body using, for example, a bolt, it is necessary to increase the axial force of the bolt and tighten the bolt so that there is no gap between the mounting portion and the seat surface, and it is sometimes necessary to increase the diameter of the bolt or to increase the strength of the seat surface. In contrast, in the present invention, the first mounting portion and the second mounting portion rigidly fixed to the vehicle body are provided at axially separated positions, whereby a large amount of elastic deformation on the vehicle body side can be ensured when the first mounting portion and the second mounting portion are fixed to the vehicle body. Therefore, when the first mounting portion and the second mounting portion are fixed to the vehicle body with, for example, bolts, the vehicle body side can be elastically deformed to eliminate the floating caused by the variation at the time of manufacture, and therefore, the first mounting portion and the second mounting portion can be fixed to the vehicle body without increasing the axial force of the bolts. Further, since the distance between the third attachment portion and the first attachment portion and the distance between the third attachment portion and the second attachment portion are smaller than the distance between the first attachment portion and the second attachment portion, the amount of elastic deformation on the vehicle body side when the third attachment portion is fixed to the vehicle body is smaller than the amount of elastic deformation on the vehicle body side when the first attachment portion and the second attachment portion are attached to the vehicle body. In contrast, in the present invention, the third mounting portion is fixed to the vehicle body via the elastic member, and thus, the floating caused by the variation in manufacturing can be eliminated without increasing the axial force of the bolt.

(2) In the present invention, the first and second attachment portions are fixed to the vehicle body without an elastic member, whereby the first and second attachment portions can be fixed more rigidly than the third attachment portion, and the cost of the elastic member can be reduced.

(3) In the present invention, the first mounting portion and the second mounting portion, which are rigidly fixed, are provided on the pinion shaft side with respect to the rack shaft in the vehicle front-rear direction, whereby displacement of the pinion shaft can be suppressed. Therefore, the responsiveness of the tire with respect to the steering force can be further improved, and the tire reaction force and the like can be more easily transmitted to the steering wheel. In addition, in the present invention, by providing the third mounting portion on the opposite side of the first mounting portion and the second mounting portion so as to sandwich the rack shaft, a large distance in the vehicle front-rear direction between the third mounting portion and an axis passing through the first mounting portion and the second mounting portion can be secured, and therefore, rotation of the gear box with respect to the vehicle body about the axis can be more effectively suppressed.

(4) In the present invention, the first front and rear portions and the second front and rear portions, which easily support the load in the vehicle front-rear direction, are provided with the first fixing portion and the second fixing portion, to which the first mounting portion and the second mounting portion are rigidly fixed, in the subframe, whereby the support rigidity of the subframe with respect to the gear box can be improved. In the present invention, the third mounting portion which does not require support rigidity as compared with the first mounting portion and the second mounting portion is fixed to the third fixing portion provided in the connecting portion which connects the first front-rear portion and the second front-rear portion, whereby the degree of freedom in the arrangement of the gear box can be improved.

(5) In the present invention, a vehicle body is divided into a sub-frame to which a gear box is attached and a main frame to which the sub-frame is attached. In the present invention, the first attachment portion in a state of being attached to the first fixing portion or the second attachment portion in a state of being attached to the second fixing portion is coupled to the main fixing portion attached to the main frame by the bead. This can further enhance the support rigidity of the gear box with respect to the vehicle body, and therefore, the responsiveness in the left-right steering can be further enhanced.

(6) As described above, the mounting portion of the gear box may slightly overhang the seating surface of the vehicle body due to variations in manufacturing of the gear box or the vehicle body. Therefore, if it is desired to fix the gear case to the vehicle body at three mounting portions using, for example, bolts, the gap between the mounting portion that is fixed last (third) and the seat face increases, and it is necessary to increase the axial force of the bolts. In contrast, in the present invention, after the first mounting portion and the second mounting portion are fixed to the vehicle body, the third mounting portion is fixed to the vehicle body. As described above, the first mounting portion and the second mounting portion are provided at positions separated in the axial direction. Therefore, since the first attachment part and the second attachment part are fixed to the vehicle body before the third attachment part is fixed to the vehicle body, a large amount of elastic deformation on the vehicle body side can be ensured when the first attachment part and the second attachment part are fixed to the vehicle body, and therefore, the first attachment part and the second attachment part can be fixed to the vehicle body without increasing the axial force of the bolt. Further, since the third mounting portion is fixed last, although the gap between the third mounting portion and the seat surface of the vehicle body tends to increase, in the present invention, the third mounting portion is elastically fixed to the vehicle body, whereby the third mounting portion can be fixed to the vehicle body without increasing the axial force of the bolt.

Drawings

Fig. 1 is a view of an engine room in a front portion of a vehicle to which a steering gear box mounting structure and a steering gear box mounting method according to an embodiment of the present invention are applied, as viewed from a front side in a traveling direction.

FIG. 2 is a plan view of the front subframe.

FIG. 3A is a front view of the front subframe.

FIG. 3B is a rear view of the front subframe.

Fig. 4 is a sectional view taken along line IV-IV in fig. 3B.

Fig. 5 is a sectional view taken along line V-V of fig. 3B.

Detailed Description

Hereinafter, an installation structure of a steering gear box and an installation method of the steering gear box according to an embodiment of the present invention will be described with reference to the drawings.

Fig. 1 is a view of the interior of an engine room 1 in the front portion of a vehicle V to which the structure and method for mounting a steering gear box according to the present embodiment are applied, as viewed from the front side in the front-rear direction of the vehicle. In the following, a vehicle V in which a steering wheel operable by a driver is provided on the right side in the vehicle width direction, that is, a so-called right-hand-wheel vehicle V, will be described. The present invention is also applicable to left steering wheel vehicles. In fig. 1, the structure of the ribs 33L and 33R, which will be described later, is not shown.

In an engine room 1 of a vehicle V, there are provided: a left front side frame 2L and a right front side frame 2R (hereinafter, referred to as front side frames 2L,2R) that constitute a part of the vehicle body; a front subframe 3 that constitutes a part of the vehicle body and is mounted on the front side frames 2L, 2R; and a steering device 5 mounted on the front sub-frame 3.

The front side frames 2L,2R are cylindrical and extend in the vehicle front-rear direction. The front side frames 2L,2R are spaced apart in the vehicle width direction and are disposed substantially in parallel. The left front side frame 2L is disposed on the left side in the vehicle width direction, and the right front side frame 2R is disposed on the right side in the vehicle width direction. The front subframe 3 is bridged between the front side frames 2L, 2R. The steering device 5 is supported by the front subframe 3 between the front side frames 2L, 2R.

The steering device 5 converts rotational movement of a steering wheel (not shown) operated by a driver on a driver's seat provided on the right side in the vehicle width direction into movement in the vehicle width direction along a rack shaft (not shown), thereby steering the left and right front wheels in the traveling direction.

The steering device 5 includes: a pinion shaft 51 extending in the vertical direction; a gear case 52 that houses a rack shaft (not shown) extending in the vehicle width direction and a front end portion of the pinion shaft 51; a rod-shaped auxiliary rod 53L and a right rod 53R which are coupled to both end portions of the rack shaft via coupling joints, not shown; and left and right guards 54L and 54R for covering joints provided at both ends of the rack shaft. The left and right front wheels are connected to the tie rods 53L,53R, respectively.

The gear box 52 includes: a cylindrical gear case body 55 extending in the vehicle width direction; a left bracket 56L provided at a left end portion 55L on the left side in the vehicle width direction of the gear case body 55; a right bracket 56R provided at a right end portion 55R on the vehicle width direction right side of the gear housing main body 55; a center bracket 56C provided between the both end portions 55L,55R in the vehicle width direction in the gear case main body 55; and a pinion shaft support portion 58 provided between the right bracket 56R and the center bracket 56C in the vehicle width direction in the gear case main body 55. The gear box main body 55, the left bracket 56L, the right bracket 56R, the center bracket 56C, and the pinion shaft support portion 58 are formed of, for example, aluminum.

The gear box main body 55 supports a rack shaft, not shown, inside thereof so as to be displaceable in the vehicle width direction. The pinion shaft support portion 58 is provided on the vehicle front-rear direction front side of the rack shaft in the gear housing main body 55. The pinion shaft support portion 58 rotatably supports a front end portion of the pinion shaft 51 extending in the vertical direction inside thereof. The front end of the pinion shaft 51 is engaged with the rack shaft inside the pinion shaft support 58 and the gear housing main body 55. More specifically, the front end of the pinion shaft 51 meshes with the rack shaft at the front side in the vehicle front-rear direction. Therefore, if a steering force is input to the pinion shaft 51 by the driver operating the steering wheel, the pinion shaft 51 rotates, and the rack shaft is displaced in the vehicle width direction to the left or right side, thereby steering the left and right front wheels.

As described above, in the present embodiment, the case where the front end portion of the pinion shaft 51 is meshed with the rack shaft on the front side in the vehicle front-rear direction is described, but the present invention is not limited thereto. The front end portion of the pinion shaft may also be engaged with the rack shaft at the rear side in the vehicle front-rear direction.

The left bracket 56L is in the form of an arm extending from the left end portion 55L of the gear housing body 55 toward the front side in the vehicle front-rear direction. In other words, the left bracket 56L extends toward the pinion shaft 51 side in the vehicle longitudinal direction with respect to the rack shaft. A left mounting portion 57L as a cylindrical first mounting portion is provided at a front end portion of the left bracket 56L.

The right bracket 56R is an arm shape extending from the right end portion 55R of the gear housing main body 55 toward the front side in the vehicle front-rear direction. In other words, the right bracket 56R extends toward the pinion shaft 51 side in the vehicle front-rear direction with respect to the rack shaft. A right mounting portion 57R as a cylindrical second mounting portion is provided at a front end portion of the right bracket 56R.

The center bracket 56C is an arm shape extending rearward from the gear housing main body 55 in the vehicle front-rear direction. In other words, the center bracket 56C extends toward the opposite side of the pinion shaft 51 with respect to the rack shaft in the vehicle front-rear direction. A center mounting portion 57C, which is a cylindrical third mounting portion, is provided at the front end portion of the center bracket 56C.

The gear box body 55 is fixed to the front subframe 3 by fastening means not shown in the drawings at three portions, i.e., a left mounting portion 57L, a right mounting portion 57R, and a center mounting portion 57C. In the present embodiment, a case where a bolt is used as a fastening means will be described, but the present invention is not limited to this.

As shown in fig. 1, the left mounting portion 57L and the right mounting portion 57R are provided at positions separated in the vehicle width direction, which is the axial direction of the rack shaft. The center mounting portion 57C is provided between the left mounting portion 57L and the right mounting portion 57R in the vehicle width direction. The left and right mounting portions 57L and 57R are disposed on the front side (i.e., the pinion shaft 51 side) in the vehicle longitudinal direction with respect to the rack shaft in plan view, and the center mounting portion 57C is disposed on the rear side (i.e., the opposite side to the pinion shaft 51) in the vehicle longitudinal direction with respect to the rack shaft in plan view.

Fig. 2 is a plan view of the front subframe 3. Fig. 3A is a front view of the front subframe 3 as viewed from the front side in the vehicle longitudinal direction, and fig. 3B is a rear view of the front subframe 3 as viewed from the rear side in the vehicle longitudinal direction. In fig. 2, for the sake of easy understanding, only the left mounting portion 57L, the right mounting portion 57R, and the center mounting portion 57C are illustrated for the structure of the steering device. In fig. 2, 3A and 3B, the axis O of the rack shaft supported by the gear box body fixed to the front subframe 3 is shown in a broken line.

The front subframe 3 is formed by joining an upper plate 3a constituting an upper portion and a lower plate 3b constituting a lower portion. Therefore, the interior of the front subframe 3 is hollow. The front subframe 3 includes: a left front-rear portion 31L extending in the vehicle front-rear direction on the left side in the vehicle width direction; a right front-rear portion 31R extending in the vehicle front-rear direction on the vehicle width direction right side; a connecting portion 32 extending in the vehicle width direction and connecting the two front and rear portions 31L, 31R; a left rib 33L provided at the left front and rear portion 31L; and a right bead 33R provided at the right front-rear portion 31R.

A center seating surface 34C is formed at a substantially center in the vehicle width direction among the upper surfaces of the coupling portions 32, and the center seating surface 34C serves as a third fixing portion to which a center mounting portion 57C of the gear box body is mounted. As shown in fig. 2, the center seating surface 34C is provided on the vehicle front-rear direction rear side of the axis O of the rack shaft, among the upper surfaces of the coupling portions 32, in plan view.

The left front-rear portion 31L extends in the vehicle front-rear direction on the vertically lower side of the left front frame 2L, and the left front frame 2L extends in the vehicle front-rear direction on the vehicle width direction left side.

A left seat surface 34L and a left bulging portion 35L are formed on the upper surface of the left front-rear portion 31L on the front side in the vehicle front-rear direction with respect to the rack shaft axis O, the left seat surface 34L serving as a first fixing portion to which a left mounting portion 57L of the gear box body is mounted, and the left bulging portion 35L serving as a main mounting portion to be mounted on the left front side frame 2L. The left seat surface 34L is provided on the upper surface of the left front and rear portion 31L on the opposite side of the center seat surface 34C so as to sandwich the rack shaft axis O. The left bulging portion 35L is provided on the vehicle width direction outer side with respect to the left seating surface 34L in plan view and slightly on the front side in the vehicle front-rear direction.

As shown in fig. 3A and 3B, the left bulging portion 35L bulges convexly to the vertically upper side, and a first left main seating surface 36L attached to the left front side frame 2L and a left sub-seating surface 37L attached to an end portion of the left bead 33L are formed at a front end portion thereof. The left sub-seat surface 37L is provided slightly inward of the first left main seat surface 36L in the vehicle width direction, that is, slightly closer to the left seat surface 34L in the vehicle width direction. As shown in fig. 3, the first left main seating surface 36L and the left sub-seating surface 37L provided at the distal end portion of the left bulging portion 35L are located vertically above the left seating surface 34L, the center seating surface 34C, and the rack shaft axis O.

Further, a second left main seating surface 38L attached to the left front side frame 2L is formed on the upper surface of the left front-rear portion 31L on the vehicle front-rear direction rear side with respect to the rack shaft axis O. As shown in fig. 3, the second left main seating surface 38L is located vertically below the first left main seating surface 36L and the rack shaft axis O. The left front-rear portion 31L is attached to the left front frame 2L at a first left main seating surface 36L and a second left main seating surface 38L on both sides in the vehicle front-rear direction sandwiching the rack shaft axis O.

The right front-rear portion 31R extends in the vehicle front-rear direction on the vertically lower side of the right front frame 2R, and the right front frame 2R extends in the vehicle front-rear direction on the vehicle width direction right side.

A right seating surface 34R as a second fixing portion to which a right mounting portion 57R of the gear box body is mounted, and a right bulging portion 35R mounted on the right front side frame 2R are formed on the front side in the vehicle front-rear direction with respect to the axis O of the rack shaft, of the upper surfaces of the right front and rear portions 31R. The right seat surface 34R is provided on the upper surface of the right front-rear portion 31R on the opposite side of the center seat surface 34C so as to sandwich the rack shaft axis O. The right bulging portion 35R is provided on the vehicle width direction outer side with respect to the right seat face 34R in plan view and slightly on the front side in the vehicle front-rear direction.

As shown in fig. 3A and 3B, the right bulging portion 35R bulges convexly to the vertically upper side, and a first right main seat surface 36R attached to the right front side frame 2R and a right sub-seat surface 37R attached to an end portion of the right bead 33R are formed at a front end portion thereof. The right sub seat surface 37R is provided slightly inward of the first right main seat surface 36R in the vehicle width direction, i.e., slightly closer to the right seat surface 34R in the vehicle width direction. As shown in fig. 3, the height in the vertical direction of the first right main seating surface 36R and the right sub-seating surface 37R provided at the front end of the right bulge 35R is almost equal to the height of the first left main seating surface 36L and the left sub-seating surface 37L provided at the front end of the left bulge 35L. That is, the first right main seating surface 36R and the right sub-seating surface 37R provided at the distal end portion of the right bulging portion 35R are located vertically above the right seating surface 34R, the center seating surface 34C, and the axis O of the rack shaft.

Further, a second right main seating surface 38R attached to the right front side frame 2R is formed on the upper surface of the right front-rear portion 31R on the vehicle front-rear direction rear side of the rack shaft axis O. As shown in fig. 3, the second right main seating surface 38R is located vertically below the first right main seating surface 36R and the rack shaft axis O. The right front-rear portion 31R is attached to the right front frame 2R at first and second right main seating surfaces 36R and 38R on both sides in the vehicle front-rear direction that sandwich the rack shaft axis O.

The left bead 33L extends in the vehicle width direction, and connects the left attachment portion 57L, which is attached to the left seat surface 34L, to the front end portion of the left bulging portion 35L. More specifically, the left bead 33L is fixed to the left sub seat surface 37L of the left bulging portion 35L at the vehicle width direction outer end 331L by a bolt, not shown, and is fixed to the left attachment portion 57L in a state of being attached to the left seat surface 34L at the vehicle width direction inner end 332L by a bolt, not shown. As shown in fig. 3A, the left sub seat surface 37L is vertically higher than the left mounting portion 57L in a state mounted on the left seat surface 34L. Therefore, the left bead 33L is inclined vertically downward from the vehicle width direction outer end 331L toward the vehicle width direction inner end 332L.

The right bead 33R extends in the vehicle width direction, and connects the right attachment portion 57R attached to the right seat surface 34R and the front end portion of the right bulging portion 35R. More specifically, the right bead 33R is fixed to the right sub seat surface 37R of the right bulging portion 35R at the vehicle width direction outer end 331R by a bolt not shown, and is fixed to the right attachment portion 57R attached to the right seat surface 34R at the vehicle width direction inner end 332R by a bolt not shown. As shown in fig. 3A, the right sub seat surface 37R is vertically higher than the right mounting portion 57R in a state mounted on the right seat surface 34R. Therefore, the right bead 33R is inclined vertically downward from the vehicle width direction outer end 331R toward the vehicle width direction inner end 332R.

Fig. 4 is a sectional view taken along line IV-IV in fig. 3B, and is a view for explaining a fastening structure of the central attachment portion 57C to the connection portion 32. As shown in fig. 4, the center mounting portion 57C is cylindrical with a through hole 571C extending in the vertical direction formed at the center thereof. A cylindrical mounting bush 59 is press-fitted into the through hole 571C of the center mounting portion 57C.

The mounting bush 59 includes: a cylindrical iron ferrule 591 extending in a vertical direction; and a rubber member 592 as a cylindrical elastic member provided on an outer peripheral surface of the iron ferrule 591. The rubber member 592 is engaged with the outer peripheral surface of the iron ferrule 591. More specifically, the mounting bushing 59 uses a bushing made by casting an iron ferrule 591 into a rubber member 592. At both end portions of the rubber member 592, flange portions 592a,592b are provided, respectively. Therefore, a fitting portion 592C having a C-shape in a cross-sectional view is formed on the outer peripheral portion of the rubber member 592. The mounting bush 59 is press-fitted into the through hole 571C by fitting the fitting portion 592C of the rubber member 592 into the inner peripheral portion of the through hole 571C of the center mounting portion 57C.

The center attachment portion 57C is attached to the center seat surface 34C by inserting a bolt 60 into a through hole 593 formed in the center of the attachment bushing 59, and further fastening the bolt 60 to a nut 61 provided on the back surface of the center seat surface 34C in the upper plate 3 a. That is, the center mounting portion 57C is elastically fixed to the center seat surface 34C via the rubber member 592 of the mounting bushing 59.

Further, the lengths of the iron ferrule 591 and the rubber member 592 along the axis of the bolt 60 are almost equal. In addition, the length of the iron ferrule 591 and the rubber member 592 along the axis of the bolt 60 is slightly longer than the length of the center mounting portion 57C along the axis of the bolt 60. Therefore, if the bolt 60 is fastened to the nut 61, the iron ferrule 591 of the mounting bush 59 will be tightly fitted with the center seat surface 34C and the bolt 60 on both end surfaces thereof and held between the center seat surface 34C and the bolt 60. In a state where the bolt 60 is fastened to the nut 61, the center mounting portion 57C is not in direct contact with the bolt 60, the center seat surface 34C, and the iron ferrule 591, but is in contact with the bolt 60, the center seat surface 34C, and the iron ferrule 591 via the rubber member 592 of the mounting bushing 59. Therefore, the vibration transmitted to the center mounting portion 57C and the displacement of the center mounting portion 57C with respect to the bolt 60, the center seat surface 34C, and the iron ferrule 591 are absorbed by the rubber member 592.

Fig. 5 is a sectional view taken along line V-V in fig. 3B, and is a view for explaining a fastening structure of the left mounting portion 57L to the left front and rear portion 31L. The fastening structure of the right attachment portion 57R to the right front-rear portion 31R is almost the same as the fastening structure of the left attachment portion 57L to the left front-rear portion 31L, and therefore, the illustration and detailed description thereof are omitted.

As shown in fig. 5, the left mounting portion 57L is cylindrical with a through hole 571L extending in the vertical direction formed at the center thereof. The lower surface 572L of the left attachment portion 57L contacts the left seat surface 34L, and the upper surface 573L of the left attachment portion 57L contacts the end 332L of the left bead 33L. The left attachment portion 57L and the end portion 332L of the left bead 33L are attached to the left seat surface 34L by inserting the bolt 62 into the through hole 571 from the left bead 33L side, and further fastening the bolt 62 to the nut 63 provided on the back surface of the left seat surface 34L in the upper plate 3 a. That is, the end portions 332L of the left attachment portion 57L and the left bead 33L are fixed to the left seat surface 34L without an elastic member, unlike the center attachment portion 57C. Therefore, the left mounting portion 57L and the end portion 332L of the left bead 33L are more rigidly fixed to the left seat surface 34L than the center mounting portion 57C. Similarly, the right mounting portion 57R and the end portion 332R of the right bead 33R are also fixed to the right seat surface 34R more rigidly than the center mounting portion 57C without an elastic member interposed therebetween.

As described above, the gear case 52 of the steering device 5 is fixed to the left seat surface 34L, the right seat surface 34R, and the center seat surface 34C of the front subframe 3 among the three portions of the left mounting portion 57L, the right mounting portion 57R, and the center mounting portion 57C.

Next, a description will be given of a procedure for attaching the gear case 52 of the steering device 5 to the front subframe 3. The gear case 52 is first rigidly fixed to the left and right mounting portions 57L and 57R and the left and right beads 33L and 33R as described above on the left and right seat faces 34L and 34R, and then the center mounting portion 57C is fixed to the center seat face 34C via the mounting bush 59 provided with the rubber member 592 as described above, thereby being mounted on the front subframe 3.

In the order of fixing the left and right mounting portions 57L and 57R, as in the case of the right-hand vehicle, it is preferable that the right mounting portion 57R relatively close to the pinion shaft receiving portion 58 is fixed to the right seat surface 34R and then the left mounting portion 57L is fixed to the left seat surface 34L, as described in the present embodiment, but the present invention is not limited thereto. The left and right mounting portions 57L and 57R may be fixed to the left and right seat surfaces 34L and 34R at the same time, or the left mounting portion 57L may be fixed to the left seat surface 34L first and then the right mounting portion 57R may be fixed to the right seat surface 34R. In the case of a left-hand-wheel vehicle, it is preferable that the left mounting portion relatively close to the pinion shaft receiving portion is fixed to the left seat surface, and then the right mounting portion is fixed to the right seat surface.

According to the mounting structure and the mounting method of the steering gear box of the present embodiment, the following effects are obtained.

(1) In the present embodiment, the left mounting portion 57L and the right mounting portion 57R provided at positions separated in the axial direction of the rack shaft are fixed to the front subframe 3 more rigidly than the center mounting portion 57C, so that the difference in the amount of displacement of the gear box 52 in the axial direction with respect to the vehicle body during left-right steering can be reduced, and the difference in responsiveness during left-right steering can be reduced. In the present embodiment, the gear case 52 is fixed to the front subframe 3 at three portions, i.e., the left mounting portion 57L, the right mounting portion 57R, and the center mounting portion 57C, so that the rotation of the gear case 52 relative to the vehicle body about the axis passing through the left mounting portion 57L and the right mounting portion 57R can be suppressed. In addition, in the present embodiment, since the center mounting portion 57C is provided between the left mounting portion 57L and the right mounting portion 57R in the axial direction, the influence of the difference in responsiveness at the time of left-right steering due to the elastic fixation of the center mounting portion 57C can be reduced.

In contrast, in the present embodiment, the left and right mounting portions 57L and 57R rigidly fixed to the front subframe 3 are provided at axially spaced positions, so that a large amount of elastic deformation on the front subframe 3 side can be ensured when the left and right mounting portions 57L and 57R are fixed to the front subframe 3. Therefore, when the left and right mounting portions 57L and 57R are fixed to the front subframe 3 by bolts, the front subframe 3 side can be elastically deformed to eliminate the floating caused by the variation in manufacturing, and therefore, the left and right mounting portions 57L and 57R can be fixed to the front subframe 3 without increasing the axial force of the bolts. Further, since the distance between the center mounting portion 57C and the left mounting portion 57L and the distance between the center mounting portion 57C and the right mounting portion 57R are smaller than the distance between the left mounting portion 57L and the right mounting portion 57R, the amount of elastic deformation on the front subframe 3 side when the center mounting portion 57C is fixed to the front subframe 3 is smaller than the amount of elastic deformation on the front subframe 3 side when the left mounting portion 57L and the right mounting portion 57R are fixed to the front subframe 3. In contrast, in the present embodiment, the center mounting portion 57C is fixed to the front subframe 3 via the mounting bushing 59 provided with the rubber member 592, so that the floating caused by the variation in manufacturing can be eliminated without increasing the axial force of the bolt.

(2) In the present embodiment, the left and right mounting portions 57L and 57R are fixed to the front subframe 3 without an elastic member, whereby the left and right mounting portions 57L and 57R can be fixed more rigidly than the center mounting portion 57C, and the cost of the elastic member can be reduced.

(3) In the present embodiment, the left and right mounting portions 57L and 57R, which are rigidly fixed, are provided on the pinion shaft 51 side with respect to the rack shaft in the vehicle front-rear direction, whereby displacement of the pinion shaft 51 can be suppressed. Therefore, the responsiveness of the tire to the steering force can be further improved, and the tire reaction force and the like can be easily transmitted to the steering wheel. In addition, in the present embodiment, by providing the center mounting portion 57C on the opposite side of the left and right mounting portions 57L and 57R so as to sandwich the rack shaft, a large distance in the vehicle longitudinal direction can be secured between the central mounting portion 57C and the axis passing through the left and right mounting portions 57L and 57R, and therefore, rotation of the gear case 52 relative to the front subframe 3 about this axis can be more effectively suppressed.

(4) In the present embodiment, the left and right seat faces 34L and 34R to which the left and right mounting portions 57L and 57R are rigidly fixed are provided at the left and right front and rear portions 31L and 31R that easily support the load in the vehicle longitudinal direction in the front subframe 3, whereby the support rigidity of the front subframe 3 with respect to the gear case 52 can be improved. In the present embodiment, the central mounting portion 57C, which does not require support rigidity as compared with the left and right mounting portions 57L and 57R, is fixed to the central seat surface 34C provided in the connecting portion 32 connecting the left and right front and rear portions 31L and 31R, whereby the degree of freedom in the arrangement of the gear case 52 can be improved.

(5) In the present embodiment, the vehicle body is divided into the front subframe 3 to which the gear box 52 is attached and the front side frames 2L,2R to which the front subframe 3 is attached. In the present embodiment, the left attachment portion 57L attached to the left seat surface 34L is coupled to the left bulging portion 35L attached to the left front side frame 2L by the left bead 33L, and the right attachment portion 57R attached to the right seat surface 34R and the right bulging portion 35R attached to the right front side frame 2R are coupled to each other by the right bead 33R. This can further enhance the support rigidity of the vehicle body frames 2L,2R,3 with respect to the gear case 52, and therefore, the responsiveness in the right-left steering can be further enhanced.

(6) In the present embodiment, the left and right mounting portions 57L and 57R are fixed to the front subframe 3, and then the center mounting portion 57C is fixed to the front subframe 3. As described above, the left and right mounting portions 57L and 57R are provided at positions separated in the axial direction. Therefore, by fixing the left and right mounting portions 57L and 57R to the front subframe 3 before fixing the center mounting portion 57C to the front subframe 3, a large amount of elastic deformation on the front subframe 3 side can be ensured when fixing the left and right mounting portions 57L and 57R to the front subframe 3, and therefore the left and right mounting portions 57L and 57R can be fixed to the front subframe 3 without increasing the axial force of the bolts. Further, by fixing the center mounting portion 57C last, although the gap between the center mounting portion 57C and the center seating surface 34C of the front subframe 3 tends to increase, in the present embodiment, the center mounting portion 57C is elastically fixed to the front subframe 3, whereby the center mounting portion 57C can be fixed to the front subframe 3 without increasing the axial force of the bolt.

While one embodiment of the present invention has been described above, the present invention is not limited to this. The detailed configuration may be appropriately modified within the scope of the present invention.

Reference numerals

V vehicle

1 Engine room

2L left front side frame (vehicle body, main frame)

2R right front side frame (vehicle body, main frame)

3 front auxiliary frame (vehicle body, auxiliary frame)

31L left front and rear (first front and rear)

31R Right front and rear (second front and rear)

32 connecting part

33L left stiffener (stiffener)

33R Right stiffener (stiffener)

34L left seat (first fixed part)

34R right seat (second fixed part)

34C center seat (third fixed part)

35L left bulge (Main mounting part)

35R right bulge (Main mounting part)

5 steering device

51 pinion shaft

52 gearbox

55 Gear case body

56L left bracket

56R right bracket

56C central support

57L left mounting section (first mounting section)

57R Right mounting section (second mounting section)

57C center mount (third mount)

58 pinion shaft support

59 mounting bush

591 iron ferrule

592 rubber component (elastic component)

Claims (6)

1. A mounting structure of a steering gear box, which is a mounting structure for mounting a gear box on a vehicle body, wherein the gear box houses a rack shaft that is displaced in a vehicle width direction by a steering force, the mounting structure characterized in that:

the gear case is fixed to the vehicle body by a first mounting portion and a second mounting portion provided at positions separated in the axial direction of the rack shaft, and a third mounting portion provided between the first mounting portion and the second mounting portion in the axial direction,

the third mounting portion is fixed to the vehicle body via an elastic member,

the first mounting portion and the second mounting portion are more rigidly fixed to the vehicle body than the third mounting portion.

2. The mounting structure of a steering gear box according to claim 1,

the first mounting portion and the second mounting portion are fixed to the vehicle body without an elastic member.

3. The mounting structure of a steering gear box according to claim 1,

a pinion shaft to which a steering force is input is engaged with the rack shaft at one side in the vehicle front-rear direction,

the first mounting portion and the second mounting portion are provided on the one side in the vehicle front-rear direction with respect to the rack shaft,

the third mounting portion is provided on the other side of the rack shaft in the vehicle front-rear direction.

4. The mounting structure of a steering gear box according to claim 1,

the gear box is arranged on the auxiliary frame of the vehicle body,

the subframe includes: a first front-rear portion and a second front-rear portion that extend in the vehicle front-rear direction; and a connecting portion extending in the vehicle width direction and connecting the first front-rear portion and the second front-rear portion;

and the first mounting part is mounted on a first fixing part arranged on the first front and rear parts,

the second mounting part is mounted on a second fixing part arranged at the second front and rear part,

the third mounting portion is mounted on a third fixing portion provided on the connecting portion.

5. The mounting structure of a steering gear box according to claim 1,

the gear box is arranged on the auxiliary frame of the vehicle body,

the subframe includes:

a first fixing portion to which the first mounting portion is mounted;

a second fixing portion to which the second mounting portion is mounted;

a third fixing portion to which the third mounting portion is mounted;

a main fixing portion mounted on a main frame of the vehicle body; and a process for the preparation of a coating,

and a rib that connects the first attachment portion in a state of being attached to the first fixing portion or the second attachment portion in a state of being attached to the second fixing portion to the main fixing portion.

6. A method of mounting a steering gear box, which mounts the gear box according to any one of claims 1 to 5 on a vehicle body, characterized in that:

the first and second mounting portions are fixed to the vehicle body, and then the third mounting portion is fixed to the vehicle body.

Images