JP2012011868A - Rack shaft supporting device and steering device for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rack shaft supporting device and a steering device for a vehicle with less noise.SOLUTION: A friction reduction sheet 20 is fixed to a front surface 19a of a sealing member 19. The friction reduction sheet 20 includes a core metal 29 and a sheet 30 stuck to a front surface 29a of the core metal 29 and including a solid lubricant. A rack shaft supporting member 18 that has retracted in an inclined state receiving reverse input from the road surface abuts upon the sheet 30 including the solid lubricant in one side-abutted state (refer to Fig.4). A one side abutted position B of the rack shaft supporting member 18 is slid toward the direction of an arrow Y1 along a front surface 20a of the friction reduction sheet 20 smoothly without resistance to lead to the contact of the entire surface of the rack shaft supporting member 18 and the friction reduction sheet 20.

Description

  The present invention relates to a rack shaft support device and a vehicle steering device including the same.

A rack and pinion type steering device is usually provided with a rack shaft support device for removing backlash between the rack and the pinion.
In the rack shaft support device, a rack shaft support member (support yoke) that can slide back and forth in a holding hole provided in the housing, a sealing member that closes the inlet of the holding hole, a rack shaft support member, and a seal A compression coil spring interposed between the members is accommodated. The rack shaft support member urged by the compression coil spring supports the rack shaft so as to be slidable in the axial direction and presses the rack shaft toward the pinion shaft.

When wear of the sliding portion of the rack shaft and the rack shaft support member progresses due to long-term use, the gap between the sealing member and the rack shaft support member becomes large, and the back and forth of the rack shaft support member Increases the date. As a result, rattle noise may occur.
Therefore, in order to suppress back and forth rattling of the rack shaft support member, an intermediate member interposed between the sealing member and the rack shaft support member and cam-coupled to the sealing member is rotated by a torsion spring. By doing so, a rack shaft support device has been proposed in which the intermediate member is moved to the sealing member side to reduce the increased gap between the intermediate member and the rack shaft support member (for example, Patent Document 1). See).

  In Patent Document 1, an elastic member such as an annular rubber is interposed in the gap between the intermediate member and the rack shaft support member. When the rack shaft support member receives a reverse input from the rack shaft side, the elastic member is completely accommodated in the annular recess in which the elastic member is accommodated, so that the rack shaft support member becomes the sealing member. It abuts on the intermediate member received by (the gap is zero).

  In addition, an annular plate is interposed between the elastic member and the intermediate member so that the intermediate member can be smoothly rotated by the torsion spring, and the surface on the intermediate member side of the annular plate is finished to a low friction surface. ing. That is, the rack shaft support member, the annular elastic member such as rubber, and the annular plate do not rotate, and the intermediate member can rotate smoothly with respect to the annular plate.

JP 2010-36610 A

However, although the gap is adjusted to an appropriate amount, there is a problem that noise due to a loud hitting sound is generated when reverse input from the road surface is received.
The present invention has been made in view of the above problems, and an object thereof is to provide a rack shaft support device and a vehicle steering device with low noise.

  The inventor of the present application has obtained the knowledge that the cause of noise at the time of reverse input from the road surface is as follows. That is, when reverse input from the road surface is input, the rack shaft support member is pushed in a state where the rack shaft is twisted. For this reason, the rack shaft support member is retreated in the holding hole while being inclined, and only the outer edge of the rear end of the inclined rack shaft support member is in a so-called one-contact state in which the rack shaft support member is in contact with the front surface of the sealing member. When the friction between the rear end of the rack shaft support member and the front surface of the sealing member is large, the part where the rear end of the rack shaft support member hits the front surface of the sealing member. And when the force which pushes a rack shaft support member overcomes the said friction, a rack shaft support member collides with the end surface of a sealing member in the whole surface, returning inclination. That is, once the energy stored in the state in which the rack shaft support member is tilted is released at a stroke, the rack shaft support member swings and the end surface of the sealing member is impacted and shocked. It was found that a big hitting sound was generated.

  The present invention has been made on the basis of such knowledge, and in order to achieve the above-mentioned object, the present invention provides a depth direction (X1) of the holding hole in the holding hole (16) formed in the housing (17). ) Slidably received in the rack shaft (8) and slidably supporting the rack shaft (8), a sealing member (19) fixed to the inlet of the holding hole, and the sealing A biasing member (21) received by a member and biasing the rack shaft support member toward the rack shaft, and a rear surface (18b) of the rack shaft support member and a front surface of the sealing member facing the rack shaft support member A rack shaft support device (15; 115; 215) in which a friction reducing sheet (20; 120; 220) containing a solid lubricant is fixed to any one of (19a) is provided (Claim 1).

  For example, in the case where the friction reducing sheet is fixed to the front surface of the sealing member, the rack shaft supporting member that has been retracted in a tilted state by receiving a reverse input from the road surface will be in a frictional reduction sheet in a single-contact state. When abutting on the front surface of the rack shaft, the part of the rack shaft support member that is in contact with one side can be smoothly slid along the front surface of the friction reducing sheet without resistance. For this reason, energy is not accumulated in the one-sided state, so that the hitting sound when the rack shaft support member moves backward can be significantly reduced. As a result, noise can be reduced.

  The friction reducing sheet includes a core metal (29; 129; 229) fixed to the one of the rear surface of the rack shaft support member and the front surface of the sealing member facing the rack shaft support member, and the surface of the core metal ( 29a; 129a; 229a), and a sheet (30; 130; 230) or coating containing a solid lubricant (claim 2). In this case, the core bar can secure sufficient strength as a friction reducing sheet. In addition, when the rack shaft support member hits against a friction reducing sheet, for example, when the rack shaft supporting member hits against the friction reducing sheet, the hitting position can be smoothly slid without resistance by the sheet containing the solid lubricant or the coating containing the solid lubricant. it can.

Moreover, the said friction reduction sheet | seat (20) may receive the rear end (21b) of the coil spring as said urging | biasing member (Claim 3). In this case, the coil spring as the urging member can be prevented from falling, and a stable urging load can be obtained.
Moreover, the said friction reduction sheet | seat (120; 220) may make the cyclic | annular form which surrounds the rear end of the coil spring as said urging | biasing member (Claim 4). In this case, the friction reducing sheet can be reduced in size, and the manufacturing cost can be reduced.

A vehicle steering device (1) that supports the rack shaft so as to be slidable in the axial direction using the rack shaft support device is preferable.
In the above description, the alphanumeric characters in parentheses represent reference numerals of corresponding components in the embodiments described later, but the scope of the claims is not limited by these reference numerals.

1 is a schematic diagram illustrating a schematic configuration of a vehicle steering apparatus to which a rack shaft support device according to a first embodiment of the present invention is applied. It is sectional drawing of the principal part of the steering apparatus for vehicles to which the rack shaft support apparatus was applied. It is an expanded sectional view of the principal part of a rack axis | shaft support member, and has shown the normal time. It is an expanded sectional view of the principal part of a rack axis | shaft support member, and has shown the state which the rack axis | shaft support member reverse | retreated by reverse input hits the friction reduction sheet. It is sectional drawing of the principal part of the rack shaft support apparatus of the 2nd Embodiment of this invention. It is sectional drawing of the principal part of the rack shaft support apparatus of the 3rd Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.
1 to 4 show a first embodiment of the present invention. Referring to FIG. 1, a vehicle steering apparatus 1 includes a steering shaft 3 connected to a steering member 2 such as a steering wheel, an intermediate shaft 5 connected to the steering shaft 3 via a universal joint 4, an intermediate shaft 5 A rack as a steering shaft having a pinion shaft 7 connected to the shaft 5 through a universal joint 6 and a rack 8a meshing with the pinion 7a provided in the vicinity of the end of the pinion shaft 7 and extending in the left-right direction of the automobile And a shaft 8. The pinion shaft 7 and the rack shaft 8 constitute a rack and pinion mechanism A as a steering mechanism.

  The rack shaft 8 is supported in a rack housing 9 fixed to the vehicle body via a rack bush 50 which is a sliding bearing so as to be linearly reciprocable along the axial direction Z1. Both end portions of the rack shaft 8 protrude to both sides of the rack housing 9, and tie rods 10 are coupled to the respective end portions. Each tie rod 10 is connected to a corresponding steered wheel 11 via a corresponding knuckle arm (not shown).

When the steering member 2 is operated and the steering shaft 3 is rotated, this rotation is converted into a linear motion of the rack shaft 8 along the left-right direction of the automobile by the pinion 7a and the rack 8a. Thereby, the turning of the steered wheel 11 is achieved.
Referring to FIG. 2, the pinion shaft 7 has an upper part 7b and a lower part 7c with the pinion 7a interposed therebetween. The pinion shaft 7 is constituted by, for example, a ball bearing and a first bearing 12 that supports the upper portion 7b of the pinion shaft 7, and a second bearing 13 that is constituted by, for example, a needle roller bearing and supports the lower portion 7c of the pinion shaft 7. It is rotatably supported in the pinion housing 14. The pinion 7 a of the pinion shaft 7 and the rack 8 a of the rack shaft 8 are meshed with each other in the pinion housing 14.

  The vehicle steering device 1 is equipped with a rack shaft support device 15. The rack shaft support device 15 includes a housing 17 having a holding hole 16 formed of a circular hole, and is accommodated in the holding hole 16 so as to be slidable along the depth direction X1 of the holding hole 16 and the rear surface of the rack 8a of the rack shaft 8. A rack shaft support member 18 that slidably supports the supported surface 8b, and a sealing screw 19 as a sealing member that is screwed into and fixed to the inlet of the holding hole 16. A female screw portion 16b is formed on the inner peripheral surface 16a at the entrance of the holding hole 16, and a male screw portion 19c of the sealing screw 19 is screwed into the female screw portion 16b.

The housing 17 of the rack shaft support device 15 is formed integrally with the pinion housing 14 from a single material, and is disposed on the opposite side of the pinion shaft 7 with the rack shaft 8 therebetween. The pinion housing 14 and the housing 17 are manufactured by die casting, for example.
A disc-shaped friction reducing sheet 20 containing a solid lubricant is fixed to the front surface 19 a of the sealing screw 19. The rack shaft support device 15 includes an urging member 21 interposed between the rack shaft support member 18 and the friction reduction sheet 20. The biasing member 21 is formed of, for example, a compression coil spring that elastically biases the rack shaft support member 18 toward the rack shaft 8 side.

  The front surface 18a of the rack shaft support member 18 is formed with a concave surface 22 that supports the rack shaft 8 so as to be slidable in the axial direction. A pad 23 slidably contacting the peripheral surface of the rack shaft 8 is attached to the concave surface 22. The rear surface 18b of the rack shaft support member 18 is provided with a recess 24 for accommodating the biasing member 21. A guide 25 is formed on the bottom of the recess 24. The guide 25 is a protrusion that is loosely fitted to the inner diameter of the front end 21a of the biasing member 21.

  On the outer peripheral surface 18c of the rack shaft support member 18, a pair of receiving grooves 26 extending in the circumferential direction and having an annular shape are formed. Each receiving groove 26 accommodates an annular elastic member 27 made of, for example, an O-ring, The holding hole 16 is in elastic contact with the inner peripheral surface 16a. The pair of elastic members 27 elastically supports the rack shaft support member 18 in the radial direction, and prevents the rack shaft support member 18 from rattling.

The front surface 20a of the friction reduction sheet 20 fixed to the front surface 19a of the sealing screw 19 and the rear surface 18b of the rack shaft support member 18 are opposed to each other with a predetermined gap S therebetween. The amount of the gap S is strictly adjusted to a predetermined value within a range of 0.05 to 0.1 mm, for example, by adjusting the screwing position of the sealing screw 19.
On the rear surface 19b of the sealing screw 19, a tool engaging hole 28 for engaging with a tool for rotating the sealing screw 19 is formed. The tool engagement hole 28 is formed in, for example, a polygonal cross section.

  With reference to FIG. 3, which is an enlarged view of FIG. 2, the friction reduction sheet 20 has a disk-shaped cored bar 29 fixed to the front surface 19 a of the sealing screw 19. A sheet 30 containing a solid lubricant is attached to a front surface 29 a as a surface of the core metal 29. As the solid lubricant, for example, PTFE, molybdenum disulfide, graphite or the like can be used. The protrusion 31 protruding from the rear surface 29 b of the core metal 29 is press-fitted into a press-fit hole 32 provided in the front surface 19 a of the sealing screw 19, whereby the friction reducing sheet 20 is fixed to the sealing screw 19. In the friction reducing sheet 20, a sheet 30 containing a solid lubricant receives the rear end 21 b of the biasing member 21.

  According to the present embodiment, the rack shaft support member 18 that has receded in response to the reverse input from the road surface abuts against the front surface 20a of the friction reduction sheet 20 in a single-contact state as shown in FIG. When this occurs, the part B of the rack shaft support member 18 is smoothly slid along the front surface 20a of the friction reducing sheet 20 in the direction of the arrow Y1 without resistance, and the rack shaft support member 18 and the friction The reduction sheet 20 can be guided to the entire surface. Therefore, since the energy is not accumulated by being caught in the one-sided state, the hitting sound when the rack shaft support member 18 is retracted can be remarkably reduced. As a result, noise can be reduced.

  In addition, since the friction reducing sheet 20 includes a core metal 29 and a sheet 30 containing a solid lubricant attached to a front surface 29 a as a surface of the core metal 29, the friction reducing sheet is formed by the core metal 29. A sufficient strength as 20 can be ensured. Further, when the rack shaft support member 18 hits against the front surface 20a of the friction reducing sheet 20 by reverse input, the position where the piece hits is attached by the sheet 30 containing a solid lubricant attached to the front surface 20a. Can slide smoothly without resistance.

Moreover, since the rear end 21b of the urging member 21 is received by the friction reducing sheet 20, the urging member 21 can be prevented from falling and a stable urging load can be obtained.
In the present embodiment, the sheet 30 containing the solid lubricant is attached to the front surface 29a of the core metal 29. However, instead of the sheet 30, the front surface 29a of the core metal 29 includes a solid lubricant. A coating (solid lubricating coating) may be coated.

  FIG. 5 shows a second embodiment of the present invention. Referring to FIG. 5, the rack shaft support device 115 of the present embodiment is mainly different from the rack shaft support device 15 of the embodiment of FIG. 3 in that the disk-shaped friction reducing sheet 20 used in FIG. 3. Instead, the friction reducing sheet 120 surrounding the rear end 21b of the urging member 21 is used. The rear end 21 b of the urging member 21 is received by the front surface 19 a of the sealing screw 19.

  The friction reducing sheet 120 has an annular cored bar 129 fixed to the front surface 19 a of the sealing screw 19. An annular sheet 130 containing a solid lubricant such as PTFE is attached to the front surface 129a as the surface of the cored bar 129. Instead of the sheet 130, a film (solid lubricant film) containing a solid lubricant coated on the front surface 129a of the core metal 129 may be used. The plurality of protrusions 131 protruding from the rear surface 129 b of the core metal 129 are press-fitted into corresponding press-fitting holes 132 provided on the front surface 19 a of the sealing screw 19, whereby the friction reducing sheet 120 is fixed to the sealing screw 19. Has been.

  In the constituent elements of the present embodiment, the same reference numerals as those of the embodiment of FIG. 3 are given to the same constituent elements as those of the embodiment of FIG. Also in the present embodiment, as in the embodiment of FIG. 3, when the reverse input from the road surface is received, the rack shaft support member 18 is not caught in the one-sided state and energy is not accumulated. Further, the hitting sound when the rack shaft support member 18 is retracted can be remarkably reduced. As a result, noise can be reduced.

Next, FIG. 6 shows a third embodiment of the present invention. The rack shaft support device 215 of the present embodiment is mainly different from the rack shaft support device 115 of the embodiment of FIG. 5 in that the rear surface of the rack shaft support member 18 is replaced with the annular friction reducing sheet 120 of FIG. The annular friction reducing sheet 220 is fixed to 18b.
The friction reduction sheet 220 includes an annular cored bar 229 fixed to the rear surface 18b of the rack shaft support member 18. An annular sheet 230 containing a solid lubricant such as PTFE is joined to the rear surface 229b as the surface of the cored bar 229. Instead of the sheet 230, a coating (solid lubricant coating) containing a solid lubricant coated on the rear surface 229b of the cored bar 229 may be used. The plurality of protrusions 231 protruding from the front surface 229 a of the core metal 229 are press-fitted into the corresponding press-fitting holes 232 provided in the rear surface 18 b of the rack shaft support member 18, so that the friction reducing sheet 220 is moved to the rack shaft support member 18. It is fixed to.

Also in the present embodiment, as in the embodiment of FIG. 5, when the reverse input from the road surface is received, the rack shaft support member 18 is not caught in the one-sided state and energy is not accumulated. Further, the hitting sound when the rack shaft support member 18 is retracted can be remarkably reduced. As a result, noise can be reduced.
The present invention is not limited to the above embodiments. For example, in each of the above embodiments, a sheet containing a solid lubricant is attached to a core metal, or a coating containing a solid lubricant is coated on a core metal. However, instead of this, the entire friction reducing sheet may be formed of a solid lubricant such as PTFE without using a cored bar. In addition, various modifications can be made within the scope of the claims of the present invention.

  DESCRIPTION OF SYMBOLS 1 ... Vehicle steering device, 2 ... Steering member, 7 ... Pinion shaft, 8 ... Rack shaft, 14 ... Pinion housing, 15; 115; 215 ... Rack shaft support device, 16 ... Holding hole, 17 ... Housing, 18 ... Rack Shaft support member, 18b ... rear surface (of rack shaft support member), 19 ... sealing screw (sealing member), 19a ... front surface of sealing screw, 20; 120; 220 ... friction reducing sheet, 21 ... biasing 129a ... 129 ... core metal, 29a; 129a ... front surface (as the surface of the core metal), 229b ... rear surface (as the surface of the core metal), 30; 130; 230 ... sheet (including solid lubricant), X1 ... depth direction (of holding hole)

Claims (5)

A rack shaft support member that is slidably accommodated in a depth direction of the holding hole in a holding hole formed in the housing and slidably supports the rack shaft;
A sealing member fixed to the inlet of the holding hole;
A biasing member that is received by the sealing member and biases the rack shaft support member toward the rack shaft,
A rack shaft support device in which a friction reducing sheet containing a solid lubricant is fixed to either the rear surface of the rack shaft support member or the front surface of the sealing member facing the rack shaft support member.   In Claim 1, the friction reducing sheet is provided on the rear surface of the rack shaft support member and the one of the front surfaces of the sealing member facing the rack shaft, and provided on the surface of the core metal, A rack shaft support device comprising: a sheet or a film containing a solid lubricant.   3. The rack shaft support device according to claim 1, wherein the friction reduction sheet receives a rear end of a coil spring as the biasing member.   The rack shaft supporting device according to claim 1 or 2, wherein the friction reducing sheet has an annular shape surrounding a rear end of a coil spring as the biasing member.   A vehicle steering apparatus that uses the rack shaft support device according to any one of claims 1 to 4 to support the rack shaft so as to be slidable in an axial direction.

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