JP2017124640A - Housing for rack-and-pinion type steering gear unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a structure that can further improve rigidity of a sub-storage part relative to a main-storage part while suppressing an increase in weight.SOLUTION: A housing for rack-and-pinion type steering gear unit is provided with a reinforcement rib 24 having an L-shape cross section and a substantially triangular shape in front view, constituted of a flat plate part 25 and a reinforcement part 26 provided while being bent forward at right angle from a tip edge of the flat plate part 25 while being bridged across the main-storage part 11a and the sub-storage part 12a constituting a housing 10a that is formed such that a light alloy such as an aluminum-base alloy is subjected to die-cast molding.SELECTED DRAWING: Figure 1

Description

  The present invention relates to an improvement in a housing constituting a rack and pinion type steering gear unit constituting a steering device of an automobile.

  Rack and pinion type steering devices are widely known and widely implemented as described in, for example, Patent Documents 1 and 2 as a steering device for automobiles. FIG. 8 shows an example of a rack and pinion type steering device that has been widely known in the past. In this steering apparatus, the rotation of the steering wheel 1 is transmitted to the input shaft 6 of the steering gear unit 5 via the steering shaft 2, the universal joint 3a, the intermediate shaft 4, and the universal joint 3b. Along with this, the pair of left and right tie rods 7, 7 are pushed and pulled to give a steered angle to the steered wheels (usually the front wheels). The illustrated example also incorporates an electric power steering device that reduces the force required to operate the steering wheel 1 using the electric motor 8 as an auxiliary power source. A tilt mechanism for adjusting the vertical position of the steering wheel 1 and a telescopic mechanism for adjusting the front-rear position are also incorporated. However, since these are not related to the gist of the present invention and are widely known in the past, detailed illustration and description thereof will be omitted.

  The steering gear unit 5 is configured as shown in FIGS. 9 to 11, and converts the rotational motion of the input shaft 6 corresponding to the pinion shaft described in the claims to the linear motion of the rack shaft 9, and 1 The pair of tie rods 7 and 7 are configured to push and pull. That is, the steering gear unit 5 includes a housing 10, the rack shaft 9, and an input shaft 6 that is a pinion shaft. Among these, the housing 10 is manufactured by die-casting a light alloy such as an aluminum alloy, and includes a main housing portion 11, a sub housing portion 12, and a cylinder portion 13. Of these, the main accommodating portion 11 has a cylindrical shape with openings at both ends in the length direction. The sub-accommodating portion 12 is provided on the outer peripheral surface of the main accommodating portion 11 near one end in the length direction (the left end in FIGS. 9 to 11). The housing 12 has a twisted position relative to the central axis. Further, the internal space of the main housing portion 11 and the internal space of the sub housing portion 12 communicate with each other. That is, the middle rear side (upper side of FIG. 10, lower side of FIG. 11) of the sub-accommodating part 12 is the front side (in FIG. 10) of the inner peripheral surface of the main accommodating part 11. It opens to the lower side (upper side in FIG. 11). The cylinder portion 13 is provided at the rear portion of the main housing portion 11 near one end in the length direction, and the front end portion communicates with the internal space of the main housing portion 11. Such a housing 10 is formed of a vehicle body (frame) by means of bolts or studs that are inserted through a pair of mounting flanges 14 and 14 fixed at two positions spaced apart in the length direction on the outer peripheral surface of the main housing portion 11. ) To support.

  The rack shaft 9 is formed by forming rack teeth 15 on the front side near the one end in the length direction. The rack shaft 9 has a round bar shape with a cylindrical outer surface except for the portion where the rack teeth 15 are formed. is there. A portion closer to the other end in the length direction of the rack shaft 9 (the right end in FIGS. 9 to 11) is disposed on the inner side of the main housing portion 11 by a slide bearing 16 installed between the rack housing 9 and the main housing portion 11. Supports displacement in direction. In this state, both end portions of the rack shaft 9 are protruded from both end openings in the length direction of the main housing portion 11.

  The input shaft 6 engages the pinion teeth 17 provided at the distal end portion with the rack teeth 15, and the base end portion is provided outside the housing 10 from the opening provided at the upper end portion of the sub-accommodating portion 12. In a protruding state, the sub-accommodating portion 12 is rotatably supported. Further, a pressing block 18 is fitted in the cylinder portion 13, and a spring 20 is provided between the pressing block 18 and a lid body 19 screwed into the rear opening of the cylinder portion 13. The pressing block 18 is elastically pressed toward the rack shaft 9. Thus, the rack shaft 9 is elastically pressed toward the pinion teeth 17 to eliminate the backlash of the meshing portion between the pinion teeth 17 and the rack teeth 15, and one end of the rack shaft 9 in the length direction. The shift portion is supported so as to be capable of axial displacement. Further, the meshing state of the meshing portion is determined regardless of the force in the direction away from the input shaft 6 applied to the rack shaft 9 as power is transmitted at the meshing portion of the rack teeth 15 and the pinion teeth 17. We are trying to maintain it properly.

  The base ends of the tie rods 7 and 7 are connected to both ends in the longitudinal direction of the rack shaft 9 via spherical joints 21 and 21, respectively. The circumference of these spherical joints 21, 21 is covered with a pair of left and right bellows 22, 22. Further, the tip portions of the tie rods 7 and 7 are inserted into the circular holes formed in the tip portions of the knuckle arms (not shown) through the studs 23 and 23 supported on the tip portions, and the tips of the studs 23 and 23 are inserted. The nut is screwed into the part so that the rocking displacement is possible. The rack shaft 9 does not rotate around its own central axis due to the engagement of the pinion teeth 17 and the rack teeth 15.

  When the input shaft 6 is rotated by operating the steering wheel 1 to give a steering angle to the pair of left and right steering wheels by the steering device incorporating the steering gear unit 5 as described above, the pinion teeth 17 and Based on the meshing with the rack teeth 15, the rack shaft 9 is displaced in the axial direction. Then, a pair of left and right knuckles in which both the knuckle arms are fixedly moved by pushing and pulling the both tie rods 7 and 7 coupled to both ends in the longitudinal direction of the rack shaft 9 to swing the two knuckle arms. Are oscillated and displaced about the king pins. Then, a desired rudder angle is imparted to both the steering wheels that are rotatably supported by the rolling bearing units.

  It is desired that the housing 10 constituting the rack and pinion type steering gear unit 5 as described above further improves the rigidity of the sub-accommodating portion 12 with respect to the main accommodating portion 11. That is, as described above, when the steering gear unit 5 is operated, the input shaft 6 and the rack shaft 9 are engaged with the pinion teeth 17 and the rack teeth 15 as the input shaft 6 rotates. Based on the separation force acting on the part, forces in directions away from each other are applied. In particular, in the case of a steering apparatus incorporating a column assist type electric power steering apparatus for applying auxiliary power from the electric motor 8 to the steering shaft 2 as shown in FIG. The separation force increases, and the forces applied to the input shaft 6 and the rack shaft 9 in the direction away from each other also increase. The force applied to the input shaft 6 is applied to the sub-accommodating portion 12 via a bearing that rotatably supports the input shaft 6, and the force applied to the rack shaft 9 is applied to the sliding bearing 16 and the pressing block 18. To the main accommodating part 11 via Further, when the steering gear unit 5 is operated, a force in the left-right direction (vehicle width direction) is applied to the input shaft 6 from the meshing portion as the rack shaft 9 moves linearly. When this lateral force is applied to the sub-accommodating portion 12 via the bearing, the sub-accommodating portion 12 moves in the lateral direction (the length direction of the main accommodating portion 11) with respect to the main accommodating portion 11. It tends to fall. Therefore, it is important to improve the rigidity of the sub-accommodating portion 12 with respect to the main accommodating portion 11 from the viewpoint of improving the durability of the steering gear unit 5. In addition, it is desirable to further improve the rigidity of the sub-accommodating portion 12 with respect to the main accommodating portion 11 from the viewpoint of improving the response related to giving a steering angle to the steered wheel based on the operation of the steering wheel 1. .

  In Patent Documents 1 and 2, in a state of being spanned between the outer peripheral surface of the main housing portion and the outer peripheral surface of the sub housing portion, and in parallel with the central axis of the main housing portion and the central axis of the sub housing portion A structure in which reinforcing ribs are provided is described. However, in the case of the structures described in Patent Documents 1 and 2, there is room for further improvement from the viewpoint of further improving the rigidity of the sub-accommodating portion relative to the main accommodating portion. In Patent Documents 1 and 2, a reinforcing rib is provided between the main housing portion and the mounting flange and inclined with respect to the central axis of the main housing portion. The technique which improves the rigidity of the said attachment flange with respect to the front-back direction and an up-down direction is described. Although it is also conceivable to apply the techniques described in Patent Documents 1 and 2 to the joint portion between the main housing portion and the sub housing portion, the sub housing in the radial direction of the outer peripheral surface of the main housing portion. Since there is a cylinder part on the opposite side of the part, it may be difficult to apply the techniques described in Patent Documents 1 and 2 as they are. Furthermore, in the case of the technique described in Patent Document 1, a plurality of reinforcing ribs are provided, which is disadvantageous in terms of weight reduction.

International Publication No. 2007/060887 JP2012-250675A

  In view of the circumstances as described above, the present invention realizes a rack and pinion type steering gear unit housing that can further increase the rigidity of the sub-accommodating portion relative to the main accommodating portion while suppressing an increase in weight. Invented so much.

The rack and pinion type steering gear unit housing of the present invention includes a main housing portion, a sub housing portion, and a reinforcing rib.
Of these, the main housing portion is cylindrical with both ends open, the rack shaft formed with rack teeth on the side surface in the axial direction can be displaced in the axial direction, and both end portions of the rack shaft Is stored in a state protruding from the openings at both ends.
Further, the sub-accommodating portion has a central axis at a position twisted with respect to the central axis of the main accommodating portion, and a part of the sub-accommodating portion is opened to the main accommodating portion, and a pinion tooth is provided on the inner end thereof. The provided pinion shaft is rotatably supported.
Further, the reinforcing rib is provided in a state of being spanned between the outer peripheral surface of the main housing portion and the outer peripheral surface of the sub-housing portion.

  In particular, in the rack and pinion type steering gear unit housing of the present invention, the reinforcing rib is a flat plate portion that is spanned between the outer peripheral surface of the main housing portion and the outer peripheral surface of the sub housing portion. The reinforcing portion is provided so as to protrude from the side surface of the flat plate portion in the thickness direction of the flat plate portion (not limited to the direction perpendicular to the flat plate portion).

When implementing the rack and pinion type steering gear unit housing of the present invention as described above, preferably, as in the invention described in claim 2, the flat plate portion is connected to the central axis of the main housing portion and the auxiliary shaft. Provided parallel to the central axis of the housing.
Preferably, as in the invention described in claim 3, the reinforcing portion is provided at a right angle to the flat plate portion.
Preferably, as in the invention described in claim 4, the reinforcing portion is provided in a direction from the side surface of the flat plate portion toward the side where the sub-accommodating portion is provided.
Preferably, as in the invention described in claim 5, the reinforcing portion is provided in a state of being bent from the leading edge of the flat plate portion.
Preferably, as in the invention described in claim 6, both ends of the reinforcing portion are respectively connected to the outer peripheral surface of the main housing portion and the outer peripheral surface of the sub-housing portion.

  According to the rack and pinion type steering gear unit housing of the present invention as described above, it is possible to ensure that the rigidity of the sub housing portion with respect to the main housing portion is further improved while suppressing an increase in weight. Therefore, when the rack and pinion type steering gear unit is operated, the steering gear unit regardless of the force applied to the main housing portion and the sub housing portion based on the force acting on the meshing portion between the pinion teeth and the rack teeth. The durability of the can be improved. Moreover, the response regarding giving a steering angle to a steering wheel based on operation of a steering ring wheel can be improved.

The perspective view which shows one example of embodiment of this invention. Similarly, the perspective view which shows the state seen from the opposite side regarding FIG. 1 with respect to the front-back direction. FIG. The rear view which similarly shows the state seen from the downward direction of FIG. Sectional drawing (A) of aa of FIG. 4, and the b section enlarged view (B) of (A). The c arrow line view of FIG. The figure similar to (B) of Drawing 5 showing other 3 examples of the shape of a reinforcement part. The partial cutaway side view which shows an example of the steering device for motor vehicles provided with the rack and pinion type steering gear unit. The partially cut front view which shows an example of the conventional structure. Similarly, the top view which cut | disconnected a part and was seen from the upper direction of FIG. Dd sectional drawing of FIG.

  1 to 7 show an example of an embodiment of the present invention. The features of the rack and pinion type steering gear unit housing of the present invention, including the present example, are characterized by devising the shape of the reinforcing rib 24, thereby suppressing an increase in weight and a sub-accommodating portion for the main accommodating portion 11a. It is in the point which implement | achieves the structure which can improve the rigidity of 12a more. The structure and operation of the other parts are the same as those of a conventionally known rack and pinion type steering gear unit housing, including the conventional structure shown in FIGS.

  The housing 10a of this example is manufactured by die casting a light alloy such as an aluminum alloy, and includes the main housing portion 11a, the sub housing portion 12a, and the cylinder portion 13. Among these, the main accommodating part 11a is a cylindrical shape which the both ends of the length direction opened. The sub-accommodating portion 12a is provided on the outer peripheral surface of the main accommodating portion 11a near one end in the length direction (the right end in FIGS. 1, 3 and 4 and the left end in FIG. 2). The central axis of 11a and the central axis of the sub-accommodating portion 12a are in a twisted positional relationship. The rear side of the intermediate portion 12a (the lower side in FIG. 3, the right side in FIGS. 5 and 6) is the front side of the inner peripheral surface of the main housing portion 11a near the one end in the length direction (see FIG. 3 on the left side of FIGS. The cylinder portion 13 is provided at the rear portion of the main housing portion 11a near one end in the length direction, and the front end portion communicates with the internal space of the main housing portion 11a. Such a housing 10a is attached to the vehicle body by bolts or studs that are inserted through a pair of mounting flanges 14 and 14 fixed at two positions spaced apart in the length direction on the outer peripheral surface of the main housing portion 11a. Support and fix.

  Furthermore, in the case of this example, the reinforcing ribs 24 having an L-shaped cross section and a substantially triangular shape in front view are provided in a state of being spanned between the outer peripheral surface of the main housing portion 11a and the outer peripheral surface of the sub housing portion 12a. ing. The reinforcing rib 24 includes a flat plate portion 25 and a reinforcing portion 26. Of these, the flat plate portion 25 has a constant thickness dimension, and is between the outer peripheral surface of the main housing portion 11a and the outer peripheral surface of the sub housing portion 12a, the main housing portion 11a and the sub housing portion 12a. Are provided in parallel with the central axis of the main housing portion 11a and the central axis of the sub housing portion 12a. In other words, the flat plate portion 25 is provided in a state of standing up from the outer peripheral surface of the main housing portion 11a in a direction parallel to a virtual plane including the central axis of the sub housing portion 12a. Moreover, the height dimension from the outer peripheral surface of the said main accommodating part 11a of the said flat plate part 25 is high as it approaches the said sub accommodating part 12a. Further, the reinforcing portion 26 is provided on the entire front end edge (side surface of the upper end portion, upper end edge in FIG. 5) of the flat plate portion 25 in a state of being bent at a right angle from the front end edge to the front. Further, the thickness dimension of the reinforcing portion 26 is, for example, about 1.2 to 2 times larger than the thickness dimension of the flat plate portion 25. However, as shown in FIG. 7A, the reinforcing portion 26 can be provided in a state of being bent at a right angle from the front end edge of the flat plate portion 25 toward the rear. Further, as shown in FIG. 7B, the reinforcing portion 26 is provided in a direction perpendicular to the flat plate portion 25 (provided so as to protrude from the front end edge of the flat plate portion 25 toward both front and rear), and the reinforcing rib 24 The cross-sectional shape may be T-shaped. Alternatively, as shown in FIG. 7C, the reinforcing portion 26 can be provided at a right angle to the flat plate portion 25 from the front end portion of the flat plate portion 25 toward the front. Further, the reinforcing portion 26 is not necessarily provided at a right angle to the flat plate portion 25. In other words, the angle formed by the flat plate portion 25 and the reinforcing portion 26 is in the range of more than 0 degree and less than 180 degrees, depending on the shape of the portion where the reinforcing rib 24 is installed and the required rigidity. Determine. In any case, in the case of this example, both ends of the reinforcing portion 26 are connected to the outer peripheral surface of the main accommodating portion 11a and the outer peripheral surface of the sub accommodating portion 12a. In this example, the thickness and the protruding amount of the reinforcing portion 26 (the protruding amount from the side surface of the flat plate portion 25) are constant over the entire length of the flat plate portion 25. The size can be changed as appropriate.

  According to the housing 10a of the present example configured as described above, the reinforcing rib 24 is provided in a state of being spanned between the outer peripheral surface of the main housing portion 11a and the outer peripheral surface of the sub housing portion 12a. A sufficient rigidity of the sub-accommodating portion 12a with respect to the main accommodating portion 11a can be ensured. Particularly in the case of this example, since the reinforcing rib 24 (the flat plate portion 25) has a substantially triangular shape when viewed from the front, the rigidity in the direction in which the sub-accommodating portion 12a falls in the width direction (the direction indicated by the arrow α in FIG. 4) is high. I can do it. Furthermore, in the case of this example, in addition to making the flat plate portion 25 into a substantially triangular shape when viewed from the front, by providing the reinforcing portion 26 in a state of being bent from the leading edge of the flat plate portion 25, among the reinforcing ribs 24, The distance from the joint portion (portion indicated by point P in FIG. 4) between the main housing portion 11a and the sub housing portion 12a, which becomes a fulcrum when the sub housing portion 12a is deformed in the direction of falling in the width direction, is the largest. The cross-sectional area of the distant part is increased. Therefore, it is possible to increase the rigidity against the sub-accommodating portion 12a falling in the width direction without increasing the thickness of the flat plate portion 25. For this reason, an increase in the weight of the housing 5 can be suppressed as compared with a case where a reinforcing rib having a large thickness is simply provided.

Further, when the sub-accommodating portion 12a tends to fall in the front-rear direction (the direction indicated by the arrow β in FIG. 6), both ends are placed on the outer peripheral surface of the main accommodating portion 11a and the outer peripheral surface of the sub-accommodating portion 12a. The connected reinforcing portion 26 stretches between the main housing portion 11a and the sub housing portion 12a. Particularly in the case of this example, one end of the reinforcing portion 26 is connected to a position (high position) sufficiently separated from the joint portion (point P) on the outer peripheral surface of the sub-accommodating portion 12a. The other end of the reinforcing portion 26 is connected to a position sufficiently separated from the joint portion (point P) on the outer peripheral surface of the main housing portion 11a. Therefore, it is possible to effectively increase the rigidity against the sub-accommodating portion 12a falling in the front-rear direction. Also, the rigidity in the torsional direction can be increased.
The reinforcing rib 24 can be made by integrally forming the housing 10a when die casting a light alloy, or by joining a member formed by bending a metal plate by welding or the like. Even when the reinforcing ribs 24 are integrally formed by die-casting, for example, the reinforcing ribs 24 can be manufactured without complicated processing such as dividing the mold only to form the reinforcing ribs 24.

DESCRIPTION OF SYMBOLS 1 Steering wheel 2 Steering shaft 3a, 3b Universal joint 4 Intermediate shaft 5 Steering gear unit 6 Input shaft 7 Tie rod 8 Electric motor 9 Rack shaft 10, 10a Housing 11, 11a Main accommodating part 12, 12a Sub accommodating part 13 Cylinder part 14 Installation Flange 15 Rack tooth 16 Slide bearing 17 Pinion tooth 18 Press block 19 Lid 20 Spring 21 Spherical joint 22 Bellows 23 Stud 24 Reinforcement rib 25 Flat plate part 26 Reinforcement part

Claims (6)

A cylindrical shape with both ends open, with the rack shaft formed with rack teeth on the side in the axial direction on the inside, allowing axial displacement, and both ends of the rack shaft projecting from the opening on both ends A main storage section for storing in,
The central axis exists at a position twisted with respect to the central axis of the main housing part, a part of the main housing part is opened to the main housing part, and the pinion shaft provided with pinion teeth on the inner end is rotatable. A supporting sub-accommodating section;
In a rack and pinion type steering gear unit housing comprising a reinforcing rib provided between the outer peripheral surface of the main housing portion and the outer peripheral surface of the sub-housing portion,
In a state where the reinforcing rib protrudes in the thickness direction of the flat plate portion from the side surface of the flat plate portion spanned between the outer peripheral surface of the main storage portion and the outer peripheral surface of the sub storage portion. A rack and pinion type steering gear unit housing comprising a reinforcing portion provided.   The rack and pinion type steering gear unit housing according to claim 1, wherein the flat plate portion is provided in parallel with a central axis of the main housing portion and a central axis of the sub housing portion.   The rack and pinion type steering gear unit housing according to any one of claims 1 to 2, wherein the reinforcing portion is provided at a right angle to the flat plate portion.   The rack and pinion type steering gear unit according to any one of claims 1 to 3, wherein the reinforcing portion is provided in a direction from a side surface of the flat plate portion toward a side on which the sub-accommodating portion is provided. Housing.   The rack and pinion type steering gear unit housing according to any one of claims 1 to 4, wherein the reinforcing portion is provided in a state of being bent from a leading edge of the flat plate portion.   The rack and pinion type steering according to any one of claims 1 to 5, wherein both ends of the reinforcing portion are connected to the outer peripheral surface of the main housing portion and the outer peripheral surface of the sub housing portion, respectively. Housing for gear unit.

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