JP2020050143A - Steering gear structure - Google Patents

Abstract

To provide a steering gear structure that allows a disc spring to be centered and that can prevent occurence of abnormal noise.SOLUTION: A steering gear structure 1 includes: a pinion 2; a rack 3 engageable with the pinion 2; a rack guide 4 supporting the rack 3 so that the rack is movable in a longitudinal direction of the rack guide; a housing 5 adapted to house the rack guide 4; a cap portion 6 attached to the housing 5 on the opposite side from the rack 3; and a disc spring 8 disposed between the rack guide 4 and the cap portion 6 to bias the rack 3 via the rack guide 4 toward the pinion 2. The rack guide 4 includes a recessed portion 44 formed by cutting a corner portion formed by an extended surface from an end surface 46 of the rack guide 4, which is located adjacent to the disc spring 8 and an extended surface of an outer circumferential surface of the rack guide 4. The outer diameter of the end surface 46 of the rack guide 4 is greater than the inner diameter of the disc spring 8 and smaller than the outer diameter of the disc spring 8. The disc spring 8 is disposed such that a portion located adjacent to the rack guide 4 is a recessed portion.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a rack and pinion type steering gear structure.

  Patent Literature 1 discloses a rack-and-pinion type steering device as a steering gear structure that changes the rotational motion of a steering wheel into a linear motion and applies a steering angle to wheels. The rack and pinion type steering device includes a pinion, a rack bar (rack), a rack guide, a gear case (housing), a lid member (cap portion), and a disc spring.

  The pinion is rotatably supported by the main body of the gear case via a steering shaft. The rack bar has rack teeth that mesh with the pinion. The rack guide supports the rack bar movably in the axial direction of the rack bar. The rack guide is formed in a cylindrical shape. The end face of the rack guide on the side opposite to the rack side (the lid member side) is formed as a flat surface. The outer diameter of this end face is larger than the outer diameter of the disc spring. The gear case has a cylindrical portion formed integrally with the main body to house the rack guide. The lid member is attached to the opening of the cylindrical portion opposite to the rack side. The lid member has a bottom plate portion and a peripheral wall portion, and is formed in a circular container shape having an open rack guide side. The end face of the peripheral wall is a flat surface. The disc spring is interposed and compressed between the end face of the rack guide and the end face of the peripheral wall of the lid member.

JP 2007-203836 A

  The outer peripheral edge of the end face of the rack guide may come into contact with the inner peripheral surface of the cylindrical portion of the gear case. When the outer peripheral edge of the end surface of the rack guide comes into contact with the inner peripheral surface of the cylindrical portion of the gear case, abnormal noise is generated. In particular, since the outer diameter of the end face of the rack guide formed of a plane is larger than the outer diameter of the disc spring, the disc spring may be shifted in the radial direction when the steering gear structure is assembled. If the disc springs are assembled in a state shifted in the radial direction, the reaction force accompanying the compression of the disc springs cannot be uniformly applied to the rack guide in the circumferential direction of the rack guide. Therefore, the rack guide rattles, and the outer peripheral edge of the end face of the rack guide contacts the inner peripheral surface of the cylindrical portion of the gear case.

  An object of the present invention is to provide a steering gear structure in which a disc spring can be centered with respect to a rack guide and generation of abnormal noise can be suppressed.

The steering gear structure according to one embodiment of the present invention includes:
A pinion that rotates in conjunction with the rotation of the steering wheel,
A rack that meshes with the pinion;
A rack guide movably supporting the rack in the longitudinal direction thereof,
A housing for accommodating the rack guide;
A cap portion attached to the opposite side of the housing from the rack side,
A steering gear structure including a disc spring interposed between the rack guide and the cap portion to bias the rack toward the pinion via the rack guide,
The rack guide has a recess formed by cutting out a corner formed by an extension surface of the disc guide side end surface of the rack guide and an extension surface of an outer peripheral surface of the rack guide,
The outer diameter of the end face of the rack guide is larger than the inner diameter of the disc spring, and smaller than the outer diameter of the disc spring,
The disc spring is arranged so that the rack guide side is concave.

  In the steering gear structure, the disc spring can be centered with respect to the rack guide, and generation of abnormal noise can be suppressed. The outer diameter of the end face of the rack guide and the inner diameter and the outer diameter of the disc spring satisfy the above-mentioned specific magnitude relationship, and the disc spring is arranged so that the rack guide side is concave, so that the concave inclined surface of the disc spring is provided. Is brought into contact with the outer peripheral edge of the end face of the rack guide. Therefore, displacement of the disc spring in the radial direction can be restricted. Since the disc spring does not shift in the radial direction, the disc spring can be centered with respect to the rack guide. Therefore, it is possible to prevent generation of abnormal noise due to contact between the disc spring and the inner peripheral surface of the housing. In addition, the centering of the disc spring allows the elastic force of the disc spring to be evenly applied to the rack guide in the circumferential direction of the rack guide. Therefore, rattling of the rack guide can be suppressed, and generation of abnormal noise due to contact between the rack guide and the housing can be suppressed.

FIG. 2 is a front view schematically showing a steering gear structure according to the first embodiment. It is sectional drawing which shows the outline of the steering gear structure cut | disconnected by the cutting line (II)-(II) of FIG.

  Embodiment 1 of a steering gear structure according to the present invention will be described below with reference to FIGS. The same reference numerals in the figures indicate the same names. In FIG. 1, “UP” indicates the upper side of the vehicle, “LWR” indicates the lower side, “LH” indicates the left side, and “RH” indicates the right side.

<< Embodiment 1 >>
[Steering gear structure]
The steering gear structure 1 according to the first embodiment is a rack and pinion type steering gear structure. This steering gear structure 1 gives a steering angle to the wheels 12 (front wheels) by changing the rotational movement of the steering wheel 11 into a linear movement. The steering wheel 11 and the steering gear structure 1 of this example are connected via a steering shaft 13, an intermediate shaft 14, and a cardan joint 15 (FIG. 1). The steering shaft 13 is connected to the steering wheel 11. The cardan joint 15 is interposed between the steering shaft 13 and the intermediate shaft 14, and between the intermediate shaft 14 and the steering gear structure 1. The steering gear structure 1 includes a pinion 2, a rack 3, a rack guide 4, a housing 5, a cap 6, an elastic member 7, and a disc spring 8 (FIG. 2). The pinion 2 rotates in conjunction with the rotation of the steering wheel 11. The rack 3 meshes with the pinion 2. The rack guide 4 supports the rack 3 movably in the longitudinal direction (vehicle width direction). The housing 5 has a guide housing part 54 that houses the rack guide 4. The cap 6 is attached to the guide housing 54 on the side opposite to the rack 3 side. The elastic member 7 and the disc spring 8 are interposed between the rack guide 4 and the cap 6. One of the features of this steering gear structure 1 is that the outer diameter of the end surface 46 of the rack guide 4 on the disc spring 8 side and the inner diameter and outer diameter of the disc spring 8 satisfy a specific magnitude relationship. Hereinafter, each configuration will be described in detail.

[Pinion]
The pinion 2 rotates in conjunction with the rotation of the steering wheel 11 (FIG. 1). The pinion 2 is connected to the intermediate shaft 14 via a cardan joint 15 in this example. A plurality of tooth portions and a plurality of tooth grooves are alternately formed on the outer peripheral surface of the pinion 2 along the circumferential direction (all are not shown). The pinion 2 is rotatably housed in a pinion housing portion 52 of the housing 5 described later (FIG. 2).

[rack]
The rack 3 moves in the longitudinal direction (vehicle width direction) with the rotation of the pinion 2. The rack 3 is a long bar extending in the vehicle width direction, and is arranged so as to intersect the axial direction of the pinion 2 (FIGS. 1 and 2). A tie rod 16 is connected to each end of the rack 3 in the vehicle width direction (FIG. 1). The movement of the rack 3 in the vehicle width direction steers the wheels 12 connected to the tie rods 16 via a knuckle arm and a steering knuckle (both not shown). On the surface of the rack 3 facing the pinion 2, a tooth groove and a tooth portion with which the tooth portion and the tooth groove of the pinion 2 mesh are formed (both are not shown). The surface of the rack 3 on the side opposite to the pinion 2 side is formed as an arc surface in this example, and is supported by the rack guide 4. The rack 3 is movably housed in a rack housing 53 of the housing 5 described later.

[Rack guide]
The rack guide 4 supports the rack 3 movably in the longitudinal direction (vehicle width direction). The rack guide 4 is provided on the side of the rack 3 opposite to the side of the pinion 2. The rack guide 4 is slidably housed in a guide housing portion 54 of the housing 5. The rack guide 4 compresses the elastic member 7 and the disc spring 8 together with the cap portion 6. Due to the reaction force caused by the compression, the rack guide 4 presses the rack 3 to urge the rack 3 toward the pinion 2. The rack guide 4 is a columnar member in this example. The rack guide 4 of the present example has a support surface 41, a groove 42, a storage portion 43, a concave portion 44, and an end surface 46.

(Support surface)
The support surface 41 is a surface that slidably supports the rack 3. The support surface 41 is formed on a surface of the rack guide 4 facing the rack 3. The shape of the support surface 41 is an arc shape corresponding to the arc surface of the rack 3.

(Groove)
The groove 42 is a groove into which the O-ring 9 is fitted. The groove portion 42 is formed in a ring shape over the entire outer circumferential surface of the rack guide 4 (a surface facing the inner circumferential surface of the guide housing portion 54) in the circumferential direction. The cross-sectional shape of the groove 42 is rectangular. The number of the grooves 42 can be appropriately selected, and is two in this example. The groove 42 can be formed by cutting or the like.

(Storage section)
The storage section 43 stores the elastic member 7. The storage section 43 is formed in a concave shape at the center of the rack guide 4 on the side opposite to the rack 3 side (the surface facing the cap section 6). The bottom surface of the storage section 43 is pressed against one end of the elastic member 7. The shape of the storage portion 43 may be a shape corresponding to the outer shape of the elastic member 7. The shape of the storage section 43 of this example is a columnar shape. The inner diameter of the storage portion 43 is slightly larger than the outer diameter of the elastic member 7 and smaller than the inner diameter of the disc spring 8. This is because the elastic member 7 is easily housed inside, and it is easy to suppress the elastic member 7 and the disc spring 8 from buffering each other.

(Recess)
The concave portion 44 secures a clearance between the outer peripheral surface of the rack guide 4 on the side opposite to the rack 3 side (the disc spring 8 side) and the inner peripheral surface of the guide housing portion 54. The concave portion 44 is formed by cutting out a corner formed by an extended surface of the end surface 46 of the convex portion 45 and an extended surface of the outer peripheral surface of the rack guide 4 in the outer peripheral edge of the rack guide 4 on the disc spring 8 side. To form a ring. The recess 44 can prevent contact between the outer peripheral edge of the rack guide 4 on the disc spring 8 side and the inner peripheral surface of the guide housing portion 54. The cross-sectional shape of the concave portion 44 can be appropriately selected, and in this example, the cross-sectional shape is rectangular. As the depth of the concave portion 44 (the length along the radial direction of the rack guide 4) increases, the clearance can be increased. In addition, the outer diameter of the end surface 46 of the rack guide 4 can be reduced. The depth of the concave portion 44 is larger than a general chamfer of a corner of the rack guide 4 or the like. The depth of the concave portion 44 in this example is set to a depth approximately equal to the depth of the groove portion 42. By making the depth of the recess 44 equal to the depth of the groove 42, the formation of the recess 44 is easy. This is because the recess 44 may be formed together with the formation of the groove 42.

(End face)
The end surface 46 is a surface of the rack guide 4 on the side of the disc spring 8. The end surface 46 of the present example is provided on the projection 45. The convex portion 45 is formed in a ring shape over the entire circumference of the rack guide 4 between the storage portion 43 and the concave portion 44 in the rack guide 4. That is, the end surface 46 is formed in a ring shape. This end surface 46 is formed of a flat surface. The outer peripheral edge of the end face 46 is chamfered. The outer diameter of the end surface 46 is smaller than the diameter of the outer peripheral surface of the rack guide 4. Since the outer diameter of the end surface 46 is smaller than the diameter of the outer peripheral surface of the rack guide 4, generation of abnormal noise due to contact between the outer peripheral edge of the end surface 46 (the convex portion 45) and the inner peripheral surface of the guide housing portion 54 is suppressed. it can. The inner diameter and the outer diameter of the end face 46 satisfy the relationship of “the inner diameter of the end face 46 of the rack guide 4 <the inner diameter of the disc spring 8 <the outer diameter of the end face 46 of the rack guide 4 <the outer diameter of the disc spring 8”. The relationship between the inner and outer diameters of the end surface 46 and the inner and outer diameters of the disc spring 8 will be described later.

[housing]
The housing 5 houses therein the pinion 2, the rack 3, the rack guide 4, and the like. The housing 5 includes a pinion housing section 52, a rack housing section 53, and a guide housing section 54. The pinion housing part 52, the rack housing part 53, and the guide housing part 54 are formed integrally so that the respective internal spaces communicate with each other.

  The pinion housing part 52 is formed in a short cylindrical shape, and houses the pinion 2 rotatably. The rack housing 53 is formed in a long tubular shape extending in the vehicle width direction, and houses the rack 3 movably. The rack housing portion 53 is provided so as to intersect the axial direction of the pinion housing portion 52. The guide housing part 54 is formed in a short cylindrical shape, and houses the rack guide 4 slidably. The guide housing portion 54 is provided so as to intersect both the axial direction of the pinion housing portion 52 and the axial direction of the rack housing portion 53.

  The guide housing portion 54 further houses a part of the cap portion 6, the elastic member 7, and the disc spring 8. On the opposite side of the guide housing portion 54 from the rack 3 side, an opening for accommodating the rack guide 4 therein is formed. This opening is sealed by the cap 6. In this example, a screw groove (not shown) for fastening the cap portion 6 is formed on the inner peripheral surface of the opening.

[Cap part]
The cap 6 compresses the elastic member 7 and the disc spring 8 together with the rack guide 4. The cap 6 is fixed to the guide housing 54 so as to close the opening of the guide housing 54. The cap part 6 of this example is formed of a columnar member that fits on the inner peripheral surface of the opening of the guide housing part 54. A thread groove is formed on the outer peripheral surface of the cap portion 6. The cap section 6 is fixed to the guide housing section 54 by screwing the screw groove of the cap section 6 into the screw groove of the opening of the guide housing section 54. The end surface (the surface on the rack guide 4 side) of the cap portion 6 is formed as a flat surface. The end face of the cap 6 presses the other end of the elastic member 7 and the convex side of the disc spring 8 by tightening the opening of the guide housing 54 in the cap 6 into the thread groove. In addition, the cap part 6 may have a bottom plate part and a peripheral wall part, and may be configured by a circular container-shaped member having the rack guide 4 side opened. In this case, the bottom plate portion presses the other end of the elastic member 7, and the end surface of the peripheral wall portion presses the convex side of the disc spring 8.

[Elastic member]
The elastic member 7 urges the rack 3 toward the pinion 2 via the rack guide 4. The elastic member 7 is arranged in the storage section 43 of the rack guide 4 and is compressed on the bottom surface of the storage section 43 and the end face of the cap section 6. The elastic member 7 urges the rack 3 toward the pinion 2 by pressing the rack guide 4 toward the rack 3 due to the reaction force caused by the compression. The elastic member 7 is constituted by a coil spring in this example.

[Disc spring]
The disc spring 8 urges the rack 3 toward the pinion 2 via the rack guide 4 together with the elastic member 7. The disc spring 8 is arranged between the end surface 46 of the rack guide 4 and the end surface of the cap portion 6 so that the rack guide 4 side is concave. The disc spring 8 is arranged on the outer periphery of the elastic member 7 so as to be concentric with the rack guide 4.

  The inner diameter and the outer diameter of the disc spring 8 satisfy the relationship of “the inner diameter of the end face 46 of the rack guide 4 <the inner diameter of the disc spring 8 <the outer diameter of the end face 46 of the rack guide 4 <the outer diameter of the disc spring 8”. Since the inner diameter of the disc spring 8 is smaller than the outer diameter of the end face 46 of the rack guide 4 and the outer diameter of the disc spring 8 is larger than the outer diameter of the end face 46 of the rack guide 4, the concave inclined surface of the disc spring 8 is formed. Is brought into contact with the outer peripheral edge of the end surface 46 (convex portion 45). Therefore, displacement of the disc spring 8 in the radial direction can be restricted. Since the disc spring 8 does not shift in the radial direction, the disc spring 8 can be centered with respect to the rack guide 4.

(Effects)
In the steering gear structure 1 according to the first embodiment, the disc spring 8 can be centered with respect to the rack guide 4, and generation of abnormal noise can be suppressed. The outer diameter of the end surface 46 of the rack guide 4 and the inner diameter and the outer diameter of the disc spring 8 satisfy the above-mentioned specific magnitude relationship, and the disc spring 8 is arranged so that the rack guide 4 side is concave, so that the disc spring 8 Is brought into contact with the outer peripheral edge of the end surface 46 (convex portion 45) of the rack guide 4. Therefore, displacement of the disc spring 8 in the radial direction can be restricted. Since the disc spring 8 does not shift in the radial direction, the disc spring 8 can be centered with respect to the rack guide 4. Therefore, generation of abnormal noise due to contact between the disc spring 8 and the inner peripheral surface of the guide housing portion 54 can be prevented. In addition, the centering of the disc spring 8 allows the reaction force accompanying the compression of the disc spring 8 to be evenly applied to the rack guide 4 in the circumferential direction of the rack guide 4. Therefore, rattling of the rack guide 4 can be suppressed, and generation of abnormal noise due to contact between the rack guide 4 and the guide housing portion 54 can be suppressed. Since the inner diameter of the disc spring 8 is larger than the inner diameter of the end face 46, mutual interference between the disc spring 8 and the elastic member 7 can be suppressed.

  The present invention is not limited to these examples, but is indicated by the appended claims, and is intended to include all modifications within the scope and meaning equivalent to the appended claims.

DESCRIPTION OF SYMBOLS 1 Steering gear structure 2 Pinion 3 Rack 4 Rack guide 41 Support surface 42 Groove part 43 Storage part 44 Depression 45 Convex part 46 End face 5 Housing 52 Pinion housing part 53 Rack housing part 54 Guide housing part 6 Cap part 7 Elastic member 8 Disc spring 9 O-ring 11 Steering wheel 12 Wheel 13 Steering shaft 14 Intermediate shaft 15 Cardan joint 16 Tie rod

Claims (1)

A pinion that rotates in conjunction with the rotation of the steering wheel,
A rack that meshes with the pinion;
A rack guide movably supporting the rack in the longitudinal direction thereof,
A housing for accommodating the rack guide;
A cap portion attached to the opposite side of the housing from the rack side,
A steering gear structure including a disc spring interposed between the rack guide and the cap portion to bias the rack toward the pinion via the rack guide,
The rack guide has a recess formed by cutting out a corner formed by an extension surface of the disc guide side end surface of the rack guide and an extension surface of an outer peripheral surface of the rack guide,
The outer diameter of the end face of the rack guide is larger than the inner diameter of the disc spring, and smaller than the outer diameter of the disc spring,
A steering gear structure in which the disc spring is arranged so that the rack guide side is concave.

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