JP2005170109A - Rack shaft support device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a rack shaft support device whereby labor for disassembly and assembly can be reduced, and locking effect of a sealing member can be prevented from being damaged. <P>SOLUTION: An aperture 17 of a holding hole 14 of the rack shaft support device 18 is sealed by the sealing member 20. A recessed part 27 is formed on an aperture forming surface 16 of a protruding part 13 of a housing 6, and thereby a female screw part 24 of the holding hole 14 is plastically deformed and a swelled part 28 is formed. A part of a peripheral surface 23a of a male screw part 23 of the sealing member 20 is pressurized without being plastically deformed by the swelled pat 28, and locking of the sealing member 20 can be achieved. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a rack shaft support device applied to a steering device.

  In the rack and pinion type steering device, the rack shaft is supported by a rack shaft support device. In general, the rack shaft support device includes a support member that is removably held in a holding hole formed in the housing, a sealing member that seals the opening of the holding hole, and a space between the supporting member and the sealing member. And an interposed elastic member. The rack shaft is slidably held in the axial direction by a support member, and the support member is biased toward the rack shaft by an elastic member. Further, the male screw part formed in the sealing member and the female screw part formed in the holding hole are screwed together so that the sealing member is held in the holding hole.

Usually, the sealing member is provided with a locking mechanism. This loosening prevention is achieved, for example, by plastically deforming the female screw portion of the holding hole and causing the meat of the housing to bite into the male screw portion. Also, there is a type in which a plurality of minute recesses are formed on the outer periphery of the sealing member at intervals in the circumferential direction, and the periphery of the female screw portion of the holding hole is plastically deformed to insert the housing meat into the recess (for example, , See Patent Document 1).
Japanese Patent Application Laid-Open No. 11-227616.

  However, when the meat of the housing is bitten into the male screw portion of the sealing member, the male screw portion is plastically deformed and damaged. Further, as described in Patent Document 1, it is difficult to securely bite the meat of the housing only into the minute recesses on the outer periphery of the sealing member. That is, also in this case, the meat of the housing bites into the male screw portion around the recess, and the male screw portion is plastically deformed and damaged.

Therefore, when removing the sealing member from the holding hole in order to disassemble the rack shaft support device, the male screw portion damages the female screw portion. For this reason, when reassembling the sealing member to the holding hole, additional work for repairing the damaged female thread portion must be performed, which is troublesome.
Further, in order to set the retracted position in the holding hole of the support member, the screwing amount of the sealing member may be finely adjusted. This fine adjustment is performed for the reason of guaranteeing the performance of the steering device. This is done after the locking is not applied, but before the locking. That is, when fine adjustment is performed, the sealing member is rotated in a state in which a part of the meat of the housing bites into the male screw part. There is a possibility that the effect of is impaired.

  The present invention has been made under such a background, and provides a rack shaft support device that can reduce labor for disassembling and assembling and can prevent the effect of preventing the locking member from loosening. For the purpose.

  In order to achieve the above object, the present invention provides a housing that slidably accommodates a rack shaft, a holding hole that is provided in the housing and that forms an opening in the opening forming surface of the housing, and can be moved forward and backward in the holding hole. The rack shaft support device comprises: a support member that is supported by the rack shaft so as to be slidable in the axial direction; and a sealing member that positions the retracted position of the support member and seals the opening of the holding hole. A female screw part formed on the inner periphery of the opening of the hole, a male screw part formed on the outer periphery of the sealing member and screwed into the female screw part of the holding hole, and an edge of the opening by local pressure on the opening forming surface of the housing A plurality of recessed portions formed in the vicinity of the opening and spaced apart in the circumferential direction of the edge of the opening, and a female threaded portion of the sealing member bulged by plastic deformation corresponding to each recessed portion. Plastic deformation of corresponding parts Characterized in that it comprises Ku further a bulge pressurizing.

  According to the present invention, it is possible to prevent the sealing member from loosening without damaging the male screw portion. For this reason, when removing a sealing member from a holding hole for maintenance etc., it can prevent that an external thread part damages an internal thread part. Therefore, when the sealing member is assembled again into the holding hole, it is not necessary to additionally process the female thread portion, and the labor required for disassembly / assembly can be significantly reduced. In addition, since the bulging part does not bite into the male threaded part, even if the sealing member is turned after the locking is applied, the bulging part is caught by the male threaded part and the bulging part is It is possible to prevent the housing from coming off from the housing, and to reliably prevent the loosening prevention effect from being impaired.

  Preferably, in the present invention, the distance between the edge of the recess and the edge of the opening may be set to 0 mm to 2 mm. In this case, by setting the distance to 0 mm or more, it is possible to prevent the bulging portion from plastically deforming (damaging) the corresponding portion of the male screw portion. By setting the distance to 2 mm or less, the bulging portion Thus, the corresponding portion of the male screw portion can be reliably pressurized.

Preferred embodiments of the present invention will be described with reference to the accompanying drawings.
FIG. 1 is a partial cross-sectional side view of a steering apparatus including a rack shaft support device according to an embodiment of the present invention. FIG. 2 is a partial cross-sectional front view of the steering device. 1 and 2, a steering device 1 includes a pinion shaft 2 connected to a steering wheel (not shown) so as to be able to rotate together, a pinion 3 provided at a tip portion of the pinion shaft 2, and a pinion 3 And a rack shaft 5 having a rack tooth portion 4 that meshes with the rack shaft 5.

  Tie rods 9 are coupled to both end portions 7 of the rack shaft 5 (only one end portion 7 is shown in FIG. 2) via ball joints 8, and each tie rod 9 is connected to a corresponding knuckle arm 10. Are connected to the corresponding wheels 11. When the steering wheel is operated to rotate the pinion shaft 2, this rotation is converted into a linear motion of the rack shaft 5 by the pinion 3 and the rack tooth portion 4. Thereby, steering of the wheel 11 is achieved.

With reference to FIG. 1, the steering device 1 includes a rack shaft support device 18. The rack shaft support device 18 is for pressing the rack shaft 5 against the pinion 3 while allowing the rack shaft 5 to move in the axial direction so as to close the engagement between the rack shaft 5 and the pinion 3.
The rack shaft support device 18 includes a housing 6 that slidably accommodates the rack shaft 5 in first and second axial directions S1 and S2 (direction perpendicular to the paper surface in FIG. 1), and an overhang portion 13 of the housing 6. And a holding hole 14 that forms an opening 17 in the opening forming surface 16 of the top portion 15 of the overhanging portion 13, and is held in the holding hole 14 so as to be movable in an axial direction V that is an advancing and retreating direction. A support member 19 that is slidably supported in the first and second axial directions S1 and S2, and a sealing member 20 made of, for example, a yoke plug that positions the retracted position of the support member 19 and seals the opening 17 of the holding hole 14. The elastic member 21 is provided between the support member 19 and the sealing member 20 and biases the support member 19 toward the rack shaft 5.

In the following, the first and second axial directions S1 and S2 of the rack shaft 5 are also simply referred to as “first axial direction S1” and “second axial direction S2,” and the axial direction V of the holding hole 14 is simply referred to as “axial”. Also referred to as “direction V”.
The housing 6 is made of, for example, an aluminum alloy, and supports the pinion shaft 2 rotatably via a bearing 12 made of, for example, a ball bearing. The overhang portion 13 is formed on the opposite side of the housing 6 from the pinion 3 with the rack shaft 5 interposed therebetween.

The support member 19 has a concave surface 19 b formed on one end surface 19 a of which contacts the back surface 5 a of the rack shaft 5. An accommodation recess 22 is formed in the other end surface 19 c of the support member 19, and the elastic member 21 is accommodated in the accommodation recess 22.
The sealing member 20 is made of steel, for example, and is accommodated in the vicinity of the opening 17 in the holding hole 14. A male screw portion 23 is formed on the outer periphery of the sealing member 20, and is screwed into a female screw portion 24 formed on the inner periphery in the vicinity of the opening 17 of the holding hole 14. One end surface 20 a of the sealing member 20 is in contact with the elastic member 21, and the elastic member 21 is compressed by the sealing member 20 and the support member 19. Further, a predetermined gap δ is provided between the one end face 20a of the sealing member 20 and the other end face 19c of the support member 19, and this is adjusted by adjusting the screwing amount of the sealing member 20 into the holding hole 14. By setting the value of the gap δ, the urging amount of the support member 19 by the elastic member 21 can be set.

  A tool engagement hole 25 is formed in the other end surface 20b of the sealing member 20, and a tool (not shown) can be engaged with the tool engagement hole 25 so that the sealing member 20 can be rotated. . The sealing member 20 is rotated, for example, when the sealing member 20 is assembled to the holding hole 14, when the screwing amount of the sealing member 20 is finely adjusted, or for the maintenance or the like, the rack shaft support device 18 is disassembled. Is the time.

  FIG. 3 is an enlarged front view around the sealing member 20, and FIG. 4 is a partial cross-sectional side view of the overhang portion 13. With reference to FIGS. 3 and 4, the present embodiment is characterized in that it is formed close to the edge 26 of the opening 17 by local pressure on the opening forming surface 16 of the overhanging portion 13 of the housing 6. A plurality of recessed portions 27 spaced apart in the circumferential direction R of the edge portion 26 of the opening 17 and the female screw portion 24 of the holding hole 14 corresponding to each recessed portion 27 are bulged by plastic deformation, and are sealed. A bulging portion 28 that pressurizes a part of the peripheral surface 23 a as a corresponding portion of the male screw portion 23 without plastic deformation is further provided, and the sealing member 20 is prevented from loosening by the bulging portion 28.

Specifically, the recessed portions 27 are provided at, for example, three locations equally in the circumferential direction R of the edge portion 26 of the opening 17. Each recessed portion 27 is formed by pressing a part of the opening forming surface 16 of the overhang portion 13 (in the direction of the black arrow) with a tool 29 such as a pin.
The bulging portion 28 is formed by a portion of the meat in the vicinity of the edge portion 26 of the overhanging portion 13 of the housing 6 being pushed inward in the radial direction of the holding hole 14 with the formation of each concave portion 27. Yes. The hardness H1 of the housing 6 is set lower than the hardness H2 of the sealing member 20 (H1 <H2). This facilitates the formation of the bulging portion 28 and prevents the bulging portion 28 from plastically deforming the male screw portion 23 of the sealing member 20.

  Specific positions and shapes of the opening 17 and the recessed portions 27 are set as follows. That is, the diameter D1 of the opening 17 is set to 36 mm, for example. Each recessed part 27 is formed in a substantially conical shape, for example, and the diameter D2 in the opening forming surface 16 is set to 1 mm to 2 mm (for example, 1.2 mm). By setting the diameter D2 to be 1 mm or more, a sufficiently large bulge portion 28 can be formed and the outer surface 23a of the male screw portion 23 can be reliably pressurized. By making the diameter D2 2 mm or less, plasticity is achieved. This is because the quality can be ensured without damaging the housing 6 due to the deformation.

The depth D3 of each recessed part 27 is set to 1 mm to 3 mm (for example, 1.5 mm). By setting the depth D3 to 1 mm or more, a sufficiently large bulge portion 28 can be formed and the outer surface 23a of the male screw portion 23 can be reliably pressurized, and the depth D3 can be 3 mm or less. This is because a crack (crack) can be prevented from occurring in the overhanging portion 13 of the housing 6.
A distance W1 between the edge 31 of each recessed portion 27 and the edge 26 of the opening 17 is set to 0 mm to 1.5 mm (for example, 1 mm). By setting the distance W1 to 0 mm or more, it is possible to prevent the bulging portion 28 from plastically deforming and damaging the outer surface 23a of the male screw portion 23. By setting the distance W1 to 1.5 mm or less, the bulging This is because the outer surface 23 a of the male screw portion 23 can be reliably pressurized by the portion 28.

Referring to FIG. 1 again, the rack shaft support device 18 is assembled in the following procedure. That is, the support member 19 and the elastic member 21 are inserted into the holding hole 14 of the overhanging portion 13 of the housing 6, and the male screw portion 23 of the sealing member 20 is screwed into the female screw portion 24 of the holding hole 14. Subsequently, the bulging portion 28 is formed by forming the recessed portion 27, and the sealing member 20 is prevented from loosening.
As shown in FIG. 2, the rack shaft 5 has bushes 33 attached to both end portions 7 (only one end portion 7 is shown in FIG. 2) of the housing 6 on the first and second axial directions S1 and S2 sides. It is supported by the housing 6 via. In the following, since the support structure of the rack shaft 5 at each end 7 of the housing 6 is the same, only the end 7 on the first axial direction S1 side will be described.

The housing 6 includes a housing chamber 34 that houses a part of the rack shaft 5 and the like, and an insertion hole 35 through which the rack shaft 5 is inserted while opening the end of the housing chamber 34 on the first axial direction S1 side. I have.
The insertion hole 35 has a large diameter portion 36, a medium diameter portion 37 having a smaller diameter than the large diameter portion 36, and a small diameter portion 38 having a smaller diameter than the medium diameter portion 37. The large-diameter portion 36, the medium-diameter portion 37, and the small-diameter portion 38 are sequentially arranged along the second axial direction S2. The large diameter portion 36, the medium diameter portion 37, and the small diameter portion 38 are collectively formed using the same tool. The large diameter portion 36 and the medium diameter portion 37 are connected via an annular step portion 39, and the medium diameter portion 37 and the small diameter portion 38 are connected via an annular step portion 40. The large-diameter portion 36 is formed in a tapered shape, and its inner diameter decreases from the first axial direction S1 toward the second axial direction S2.

A stopper member 41 is disposed on the large diameter portion 36, and a bush 33 is disposed on the medium diameter portion 37 and the small diameter portion 38, and the stopper 33 prevents the bush 33 from coming off the housing 6.
Specifically, the bush 33 includes a cylindrical main body portion 42 and a flange portion 43 formed on the outer periphery of the end portion of the main body portion 42 on the first axial direction S1 side. The main body portion 42 is fitted into the small diameter portion 38 and the rack shaft 5 is inserted therethrough. The collar portion 43 is accommodated in the medium diameter portion 37, and the movement in the second axial direction S2 is restricted by the end surface 43a on the second axial direction S2 side being in contact with the annular stepped portion 40. .

  The stopper member 41 is an annular member made of metal, and regulates the movement of the rack shaft 5 in the second axial direction S <b> 2 by coming into contact with, for example, one end surface 8 a of the ball joint 8. The stopper member 41 is fixed to the housing 6 by being press-fitted into the large diameter portion 36 or the like. The end surface 41 a on the second axial direction S <b> 2 side of the stopper member 41 is positioned in the axial direction with respect to the housing 6 by contacting the annular step portion 39. The end surface 41a is in contact with the end surface 43b of the flange portion 43 of the bush 33 on the first axial direction S1 side, and restricts the movement of the flange portion 43 in the first axial direction S1.

The assembly of the bush 33 and the stopper member 41 to the housing 6 is performed as follows. That is, the bush 33 is inserted from the large diameter portion 36 into the insertion hole 35, the main body portion 42 is fitted into the small diameter portion 38, and the end surface 43 a of the flange portion 43 is brought into contact with the annular step portion 40. Next, the stopper member 41 is fixed to the housing 6 by press-fitting the large-diameter portion 36 or the like.
Thus, compared to the conventional configuration, that is, a configuration in which an annular groove is provided instead of the medium diameter portion 37 and the flange portion of the bush is deformed and fitted into the annular groove, the bush 33 is extremely easy and impossible. It can be assembled to the housing 6 without being deformed. Moreover, since it is not necessary to replace the tool after forming the insertion hole and separately form an annular groove, the number of manufacturing steps can be reduced and the manufacturing cost can be further reduced. Further, the configuration in which the stopper member 41 is fitted into the large-diameter portion 36 sufficiently secures the area of the end surface 41b on the first axial direction S1 side of the stopper member 41 necessary to receive the one end surface 8a of the ball joint 8. be able to. For this reason, it is not necessary to separately provide a collar or the like on the stopper member in order to ensure the area of the end face, and the manufacturing cost can be further reduced through the reduction of the component cost.

  As described above, according to the present embodiment, it is possible to prevent the sealing member 20 from loosening without damaging the male screw portion 23. For this reason, it is possible to prevent the male screw portion 23 from damaging the female screw portion 24 when the sealing member 20 is removed from the holding hole 14 for maintenance or the like. Therefore, it is not necessary to additionally process the female thread portion 24 when the sealing member 20 is assembled again into the holding hole 14, and the labor required for disassembly / assembly can be significantly reduced. Further, since the bulging portion 28 does not bite into the male screw portion 23, even if the sealing member 20 is turned and the screwing amount is finely adjusted after the locking is applied, the bulging portion 28 is caught on the male screw portion 23. It can prevent that this bulging part 28 peels off from the overhang | projection part 13, and can prevent reliably that the effect of a locking prevention will be impaired.

Further, by setting the distance W1 between the edge 31 of the recessed portion 27 and the edge 26 of the opening 17 to be 0 mm or more, the bulging portion 28 plastically deforms (damages) the peripheral surface 23a of the male screw portion 23. This can be prevented, and by making the distance W1 1.5 mm or less, the peripheral surface 23a of the male screw portion 23 can be reliably pressurized by the bulging portion 28.
In addition, this invention is not limited to the content of the above embodiment, A various change is possible within the range of a claim statement. For example, instead of the recessed portion 27, a recessed portion 45 having a rectangular shape when viewed from the front may be provided as shown in FIG. In this case, the dimension of each recessed part 45 is set as follows. That is, the length L1 of each recess 45 is set to 3 mm to 5 mm (for example, 3.5 mm), and the width L2 is set to 1 mm to 2 mm (for example, 1.5 mm). The distance W2 between the edge 46 of each recessed portion 45 and the edge 26 of the opening 17 of the holding hole 14 is set to 1 mm to 2 mm (for example, 1.2 mm). Furthermore, as shown in FIG. 6, the depth L3 of each recessed part 45 is set to 1 mm-3 mm (for example, 1.5 mm).

  Furthermore, the shape of each recessed portion 45 may be formed in an arc shape when viewed from the front. In the above embodiments, the number of the recessed portions 27 and 45 may be 2 or less, or 4 or more.

It is a partial cross section side view of a steering device provided with the rack axis | shaft support apparatus of one embodiment of this invention. It is a partial cross section front view of a steering device. It is an enlarged front view around a sealing member. It is a partial cross section side view of an overhang | projection part. It is an enlarged front view of the recessed part of other embodiment of this invention. It is sectional drawing which follows the II-II line of FIG.

Explanation of symbols

5 rack shaft 6 housing 14 holding hole 16 opening forming surface 17 opening 18 rack shaft support device 19 support member 20 sealing member 23 male screw portion 23a outer surface (corresponding portion)
24 female thread portion 26 edge portion of opening 27 concave portion 28 bulging portion 31 edge portion of concave portion 45 concave portion 46 edge portion of concave portion W1 distance W2 distance R circumferential direction S1 first axial direction S2 second Biaxial direction

Claims (2)

A housing that slidably accommodates the rack shaft, a holding hole that is provided in the housing and that forms an opening in the opening forming surface of the housing, and is slidably held in the holding hole and slides in the axial direction on the rack shaft In a rack shaft support device comprising a support member that supports the seal member and a sealing member that positions the retracted position of the support member and seals the opening of the holding hole.
An internal thread formed on the inner periphery of the opening of the holding hole;
A male screw portion formed on the outer periphery of the sealing member and screwed into a female screw portion of the holding hole;
A plurality of recesses formed close to the edge of the opening by local pressure on the opening forming surface of the housing and spaced apart in the circumferential direction of the edge of the opening;
The rack further comprising: a bulging portion that bulges by plastic deformation to the female screw portion of the holding hole corresponding to each recessed portion, and pressurizes the corresponding portion of the male screw portion of the sealing member without plastic deformation. Shaft support device.   2. The rack shaft support device according to claim 1, wherein a distance between the edge of the recessed portion and the edge of the opening is set to 0 mm to 2 mm.

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