JP2015021553A - Telescopic shaft - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a telescopic shaft which can prevent fletching.SOLUTION: A telescopic shaft comprises: an outer shaft part 1 formed with a female spline 3; an inner shaft part 6 formed with a male spline 5 and a diameter-contracted part 8; and a wobbling prevention member 9 composed of an elastic body which elastically abuts on the diameter-contracted part 8, and prevents wobbling between the female spline 3 and the male spline 5. In the wobbling prevention member 9, an area which is obtained by projecting a contact point m between a first leg part 10 and the diameter-contracted part 8 to a plane which intersects with a vertical line progressing toward an axial line of the diameter-contracted part 8 from the center of a circumferential direction of a flank part 12 is set as a first projection area, an area which is obtained by projecting a contact point n between a second leg part 11 and the diameter-contracted part 8 to the plane which intersects with the vertical line progressing toward the center of the circumferential direction of the flank part is set as a second projection area, and the second projection area are set larger than the first projection area.

Description

  The present invention relates to a telescopic shaft.

  The above-mentioned telescopic shaft is used as, for example, an automobile steering shaft. The telescopic shaft is used as an intermediate shaft that connects, for example, a steering shaft of an automobile and a steering mechanism such as a rack and pinion mechanism. In this case, the telescopic function is used for adjusting the height of the handle, absorbing the impact at the time of the secondary collision, or assembling.

  Generally, a spline or a serration is employed as a structure for fitting a pair of shaft portions included in the telescopic shaft. For example, the end of the inner shaft having a male spline that engages with the female spline can be inserted into the fitting hole having the female spline formed at the end of the outer shaft so that both shafts can rotate integrally. Combine.

  In this case, a clearance is provided between the male spline and the female spline so that the inner shaft portion can be inserted into the fitting hole. However, this clearance is damaged, and both shaft portions are relatively displaced in the radial direction and the circumferential direction, which causes an unpleasant rattling sound to the driver. Therefore, a telescopic shaft 51 using a backlash preventing member 58 as shown in FIG. 8 is conventionally known (Patent Document 1).

  In the telescopic shaft 51 of Patent Document 1, a male spline 53 is formed on the inner shaft portion 52, and a female spline 54 that fits into the male spline 53 is formed on the inner peripheral surface of the fitting hole 56 of the outer shaft portion 55. ing. The male spline 53 is divided into two parts in the axial direction as a first portion 53 a and a second portion 53 b, and a reduced diameter portion 57 is formed between both the portions 53 a and 53 b, and between the reduced diameter portion 57 and the female spline 54. A backlash prevention member 58 is disposed.

  As shown in FIGS. 8 and 9, the backlash preventing member 58 has a pair of curved legs 59 extending in the circumferential direction of the diameter-reduced portion 57, curves in the same direction as the legs 59, and curves in the direction M <b> 1. The leg portion 59 is made of an elastic body having a body portion 60 that is bent in a direction M2 perpendicular to the leg portion 59, and the body portion 60 is brought into elastic contact with the female spline 54 of the outer shaft portion 53.

Japanese Utility Model Publication No. 7-40360

  In Patent Document 1, in order to prevent rattling noise, the backlash preventing member 58 elastically contacts the body portion 60 with the female spline 54 of the outer shaft portion 53 while supporting the leg portion 59 with the reduced diameter portion 57. . When a reverse input load from the wheel or an input torque from the steering wheel is applied during traveling, the backlash prevention member 58 repeatedly expands and contracts, and the contact portion between the leg portion 59 of the backlash prevention member 58 and the reduced diameter portion 57. Are always supported at the same location, so fretting may occur. Therefore, although a lubricant is applied, fretting may occur due to lubricant outflow when used for a long period of time.

  Therefore, an object of the present invention is to provide a telescopic shaft that can prevent fretting.

  In order to achieve the above object, according to the first aspect of the present invention, there is provided an outer shaft portion in which a female spline is formed in a fitting hole, a male spline that engages with the female spline on an outer periphery, and the male spline. An inner shaft portion that is divided in the axial direction and has a circular cross section and formed with a reduced diameter portion that is smaller than the valley diameter of the male spline, and elastically abuts the reduced diameter portion, and the gap between the female spline and the male spline is loose. A backlash preventing member made of an elastic body to prevent, the backlash preventing member extending in one circumferential direction of the diameter-reduced portion, curved and abutted against the diameter-reduced portion; The second leg that extends in the other direction in the circumferential direction of the reduced diameter portion and curves to contact the reduced diameter portion is connected to the first leg and the second leg, and more than these. A body that curves on the outer diameter side and abuts against the female spline. In the retractable shaft, an area when the contact portion of the first leg portion and the reduced diameter portion is projected onto a plane orthogonal to a perpendicular line extending from the circumferential center of the trunk portion toward the axis of the reduced diameter portion. Is the first projected area, and the contact point of the second leg portion and the reduced diameter portion is projected onto a plane orthogonal to a perpendicular line from the circumferential center of the trunk portion toward the axis of the reduced diameter portion. The second projected area is defined as the second projected area, and the second projected area is larger than the first projected area.

  According to the above configuration, when a reverse input load or an input load is applied between the outer shaft portion and the inner shaft portion, the backlash preventing member repeatedly expands and contracts. When the backlash preventing member shrinks, slip occurs between the reduced diameter portion and the first leg portion and between the reduced diameter portion and the second leg portion. Since the second projected area of the contact point between the second leg and the reduced diameter part is larger than the first projected area of the contact point between the first leg and the reduced diameter part, the second leg and the reduced diameter part. Since the slip at the contact point is smaller than the slip at the contact point between the second leg portion and the reduced diameter portion, the backlash preventing member rotates and moves in the other direction in the circumferential direction and does not stay in the same place. Therefore, fretting can be prevented.

  Furthermore, in the invention according to claim 2, the circumferential length of the second leg is set to be the circumferential direction of the first leg so that the second projected area is larger than the first projected area. The gist is that it is longer than the length.

  According to the above configuration, the circumferential length of the second leg is longer than the circumferential length of the first leg, the second projected area is larger than the first projected area, and the first leg Since the slip at the contact point between the portion and the reduced diameter portion is smaller than the slip at the contact point between the second leg portion and the reduced diameter portion, the backlash prevention member rotates and moves in the other direction in the circumferential direction and remains in the same place. Disappear. Furthermore, the material cost can be reduced in the direction where the length of the leg portion in the circumferential direction is short, and when pressed against the reduced-diameter portion, it is more widened and can be easily fitted into the reduced-diameter portion, and can be easily mounted, thereby preventing fretting. .

  According to a third aspect of the present invention, the axial width of the second leg is set to be the axial width of the first leg so that the second projected area is larger than the first projected area. The main point is that it is larger.

  According to the above configuration, the axial width of the second leg is larger than the axial width of the first leg, and the second projected area is larger than the first projected area. Since the slip at the contact point between the leg part and the reduced diameter part is smaller than the slip at the contact part between the second leg part and the reduced diameter part, the backlash preventing member rotates and moves in the other direction in the circumferential direction. It will not stay. Furthermore, in a direction smaller than the axial width of the leg portion, if it is pressed against the reduced diameter portion, it spreads and fits into the reduced diameter portion, so that mounting is easy and fretting can be prevented.

  Furthermore, in the invention described in claim 4, the second leg is formed with a second recess for reducing contact with the reduced diameter portion, and the contact with the reduced diameter portion is reduced on the first leg. The gist is that a first recess is formed, and the first recess is formed in a larger number than the second recess so that the second projection area is larger than the first projection area.

  According to the above configuration, since the first projected area is larger than the second recessed area so that the second projected area is larger than the first projected area, the contact portion between the first leg and the reduced diameter section Since the slippage at is smaller than the slip at the contact point between the second leg portion and the reduced diameter portion, the backlash preventing member rotates and moves in the other direction in the circumferential direction and does not stay in the same place. Furthermore, since the lubricant can be held in the first recess and the second recess, fretting due to lubricant outflow can be prevented.

  ADVANTAGE OF THE INVENTION According to this invention, the telescopic shaft which can prevent a fretting can be provided.

The disassembled perspective view of the telescopic shaft which concerns on 1st embodiment of this invention. The schematic side view of the inner-shaft part with which the rattle prevention member which concerns on 1st embodiment of this invention was mounted | worn. FIG. 2A is a schematic cross-sectional view of the portion A-A showing a mounting state of the rattle prevention member according to the first embodiment of the present invention. The perspective view of the rattle prevention member concerning a first embodiment of the present invention. Engagement of the reduced diameter portion with the first and second leg portions in a horizontal plane perpendicular to the perpendicular from the center in the circumferential direction of the trunk portion of the backlash preventing member according to the first embodiment of the present invention to the reduced diameter portion The projection surface figure of a surface. The perspective view of the rattle prevention member concerning a second embodiment of the present invention. The perspective view of the rattle prevention member concerning a third embodiment of the present invention. The perspective view of the conventional rattle prevention member. The exploded perspective view of the conventional telescopic shaft.

  A telescopic shaft according to a first embodiment of the present invention will be described with reference to the accompanying drawings. FIG. 1 is an exploded perspective view of a telescopic shaft according to a first embodiment of the present invention, and FIG. 2 is a side view of a backlash preventing member attached to one shaft portion. First, as shown in FIG. 1, the telescopic shaft has a male spline 5 that engages with the female spline 3 in the fitting hole 4 having the female spline 3 formed at the end of the outer shaft portion 1. The formed inner shaft portion 6 is inserted and configured.

A male spline 5 is formed on the outer periphery of the end portion of the inner shaft portion 6, and the male spline 5 includes a first male spline 5 a and a second spline 5 b which are located on both sides of the reduced diameter portion 8 in the axial direction. It is divided into two.
In FIG. 1, the first male spline 5a, the second spline 5b, and the female spline 3 are schematically shown. A looseness preventing member 9 made of an elastic body is attached to the reduced diameter portion 8. The backlash prevention member 9 is formed by press-molding a sheet metal material.

  As shown in FIGS. 1, 2, and 3, the backlash preventing member 9 includes a first leg portion 10 that is curved by extending in one circumferential direction P <b> 1 (see FIG. 3) of the reduced diameter portion 8, and A second leg portion 11 that is curved by extending in the other direction P2 in the circumferential direction of the reduced diameter portion 8 and a trunk portion 12 that connects between the first leg portion 10 and the opposite one end portions of the second leg portion 11. With. The body portion 12 elastically presses the female spline 3 of the outer shaft portion 1 on the outer side of the curve than the first leg portion 10 and the second leg portion 11.

  The first leg portion 10 and the second leg portion 11 are bent in the opposite directions in the circumferential direction with the same curvature radius R (corresponding to the radius of the reduced diameter portion 8). The trunk portion 12 has a center CL at the center, and a radius of curvature R1 of the outer periphery by a circumferential angle α is larger than the radius of curvature R of the first leg portion 10 and the second leg portion 11 (R1> R). The spline 3 is formed with the same radius of curvature as the minimum inner diameter position of the spline 3. The angle α in the circumferential direction is set to an angle at which the spline teeth of the female spline are in contact with at least two or more.

  Then, when the inner shaft portion 6 is inserted into the outer shaft portion 1 to form the steering shaft, the backlash preventing member 9 is attached to the inner shaft portion 6. The first leg portion 10 and the second leg portion 11 abut on the reduced diameter portion 8 of the inner shaft portion 6.

  Next, the male spline 5 of the inner shaft portion 6 is held in a state where the body portion 12 of the backlash preventing member 9 is pressed and the first leg portion 10 and the second leg portion 11 are pressed against the reduced diameter portion 8 of the inner shaft portion 6. Insert into the female spline 3 of the outer shaft 1. In the male spline 5 and the female spline 3 on the opposite side to the body portion 12, the inner shaft portion 6 is offset to the opposite side of the body portion 12 with respect to the outer shaft portion 1 so that they are in contact with each other. A gap is formed between the male spline 5 and the female spline 3 on the body 12 side, and the body 12 contacts the female spline 3.

  A contact state between the assembled anti-rattle member 9 and the reduced diameter portion 8 of the inner shaft portion 6 will be described. Projection planes of contact portions between the first leg portion 10 and the second leg portion 11 and the reduced diameter portion 8 in a plane orthogonal to a perpendicular line from the circumferential center of the trunk portion 12 to the axis of the reduced diameter portion 8 are shown. This is shown in FIG. As shown in FIG. 5, the first projected area of the contact portion m between the first leg portion 10 and the reduced diameter portion 8 is S1, and the second projected portion n of the contact portion n between the second leg portion 11 and the reduced diameter portion 8. The projected area is S2. Accordingly, the first projected area S1 having a short length of the first leg 10 is smaller than the second projected area S2 having a long length of the second leg.

  According to the first embodiment described above, when a reverse input load or an input load acts between the outer shaft portion 1 and the inner shaft portion 6, the backlash preventing member 9 repeats expansion and contraction. When the backlash preventing member 9 contracts, slip occurs between the reduced diameter portion 8 and the first leg portion 10 and between the reduced diameter portion 8 and the second leg portion 11. Since the first projection area S1 is smaller than the second projection area S2, the slip at the contact point m between the first leg portion 10 and the reduced diameter portion 8 is the contact portion between the second leg portion 11 and the reduced diameter portion 8. Since it is smaller than the slip at n, the backlash preventing member 9 rotates and moves in the other direction in the circumferential direction and does not stay in the same place. Therefore, fretting can be prevented at the same place.

  6 and 7 show the second and third embodiments of the present invention. This will be described with reference to these drawings. These embodiments are mainly different from the first embodiment of FIG. 1 in that backlash preventing members 29 and 39 that can prevent backlash in the rotational direction of both shaft portions 1 and 6 are used. The different points of the rattling prevention members 29 and 39 will be described below. The other diameter-reduced portions 8, the outer shaft portion 1, the curvature radius R1 of the leg portions of the backlash preventing members 29 and 39, and the curvature radius R of the trunk portion are the same as those in the first embodiment shown in FIG. .

With reference to FIG. 6, the rattle prevention member 29 of the second embodiment is a pair of first leg portions 30 that are bent in one circumferential direction P <b> 1 of the reduced diameter portion 8 and the circumference of the reduced diameter portion 8. A second leg 31 that curves in the other direction P2 of the direction and curves, and a trunk 32 that connects between the first leg 30 and the opposite one end of the second leg 31.
The trunk portion 32 elastically presses the female spline 3 of the outer shaft portion 1 on the outer side of the curve than the first leg portion 30 and the second leg portion 31. The first leg portion 30 and the second leg portion are set so that the total axial width of the pair of first leg portions 30 is smaller than the axial width of the second leg portion 31 by q. 31 is produced.

  The pair of first leg portions 30 and the second leg portions 31 are bent in the opposite directions in the circumferential direction with the same radius of curvature R (corresponding to the radius of the reduced diameter portion 8). The body portion 32 has an outer peripheral radius of curvature R1 larger than the radius of curvature R of the pair of first leg portion 30 and second leg portion 31 (R1> R), and has the same radius of curvature as the minimum inner diameter position of the female spline 3. It is formed as follows.

  According to the above configuration, the axial width of the pair of first leg portions 30 is smaller than the axial width of the second leg portion 31 so that the pair of first leg portions 30 and the reduced diameter portion 8 are in contact with each other. Since the first projected area of the location is smaller than the second projected area of the contact location between the second leg portion 31 and the reduced diameter portion 8, the slip at the contact location between the first leg portion 30 and the reduced diameter portion 8 is The backlash prevention member 39 rotates and moves in the other direction in the circumferential direction because it is smaller than the slip at the contact point between the two leg portions 31 and the reduced diameter portion 8 and does not stay in the same place. Therefore, fretting can be prevented. Furthermore, in the direction where the axial width of the first leg portion 30 is small, there is an effect that if the first leg portion 30 is pressed against the reduced diameter portion 8, the first leg portion 30 expands and is fitted into the reduced diameter portion 8.

  Referring to FIG. 7, the rattle prevention member 39 according to the third embodiment of the present invention includes a pair of first leg portions 40 that are curved by extending in one circumferential direction P <b> 1 of the reduced diameter portion 8, and a reduced diameter. A pair of second leg portions 41 that are curved in the other direction P2 in the circumferential direction of the portion 8 and a body portion that connects between the first leg portion 40 and the opposite one end portions of the second leg portion 41. 42. On the inner peripheral surfaces of the pair of first leg portions 40 and the pair of second leg portions 41, an axial first recess 40a and a second recess 41a are formed, respectively. The number of first recesses 40 a formed in the pair of first leg portions 40 is greater than the number of second recesses 41 a formed in the pair of second leg portions 41. Thus, the contact location between the pair of first leg portions 40 and the reduced diameter portion 8 is smaller than the contact location between the pair of second leg portions 41 and the reduced diameter portion 8. Moreover, the trunk | drum 42 elastically presses the female spline 3 of the outer-shaft part 1 on the outer side of a curve rather than the 1st leg part 40 and the 2nd leg part 41. FIG.

  According to the above configuration, the number of the second recessed portions 41a is larger than that of the first recessed portion 40a so that the second projected area is larger than the first projected area. Since the slip at the contact point of the portion 8 is smaller than the slip at the contact point of the second leg portion 41 and the reduced diameter portion 8, the backlash prevention member 39 rotates and moves in the other direction in the circumferential direction and does not stay in the same place. . Furthermore, since the lubricant can be held in the first recess 40a and the second recess 41a, fretting due to lubricant outflow can be prevented.

  In addition, this invention is not limited to said each embodiment, For example, the film which coat | covered the synthetic resin which has a low friction coefficient, such as a fluororesin, is provided in at least one of the male spline 5 or the female spline 3, for example You may do it. In this case, the sliding resistance between the female spline 3 and the male spline 5 can be reduced by the synthetic resin coating. Particularly, since the sliding resistance of the female spline 3 and the rattle prevention member 9 is reduced by the synthetic resin coating, and the rattle prevention member 9 made of an elastic body is used to prevent rattling noise, the rattle prevention effect is extremely high. And fretting due to lubricant spillage can be prevented.

  The telescopic shaft of the present invention can be used as an intermediate shaft that connects the steering shaft and a steering mechanism such as a rack and pinion mechanism, in addition to being used as a steering shaft. In addition, various modifications can be made within the scope of the claims of the present invention.

DESCRIPTION OF SYMBOLS 1 ... Outer shaft part, 3 ... Female spline, 3a ... Valley part, 4 ... Fitting hole, 5 ... Male spline, 5a ... 1st male spline, 5b ... 2nd male spline, 6 ... Inner shaft part, 8 ... diameter-reduced part, 9 ... rattle prevention member, 10, 11 ... leg part, 10a, 11a ... one end part (opposing end part), 10b, 11b ... tip part, 12 ... trunk part, 12a ... apex part

Claims (4)

An outer shaft portion in which a female spline is formed in the fitting hole and a male spline that engages with the female spline are formed on the outer periphery, and the male spline is divided in the axial direction, and has a circular cross section from a valley diameter of the male spline. An inner shaft portion formed with a reduced diameter portion and a backlash preventing member made of an elastic body that elastically contacts the reduced diameter portion and prevents backlash between the female spline and the male spline. A member that extends and curves in one direction in the circumferential direction of the reduced-diameter portion and contacts the reduced-diameter portion; and a member that extends and curves in the other direction in the circumferential direction of the reduced-diameter portion and A second leg that abuts on the reduced diameter part, a body part that connects the first leg part and the second leg part, curves on the outer diameter side from these, and abuts on the female spline; A telescopic shaft having the first leg and the front The area when the contact portion of the reduced diameter portion is projected onto a plane orthogonal to a perpendicular line extending from the circumferential center of the body portion toward the axis of the reduced diameter portion is defined as a first projected area, and the second leg portion And the second projected area is an area when the contact portion of the reduced diameter portion is projected onto a plane orthogonal to a perpendicular line extending from the circumferential center of the body portion toward the axis of the reduced diameter portion. A telescopic shaft having an area larger than the first projected area The circumferential length of the second leg is longer than the circumferential length of the first leg so that the second projected area is larger than the first projected area. Telescopic shaft as described in The axial width of the second leg is larger than the axial width of the first leg so that the second projected area is larger than the first projected area. Telescopic shaft as described A second recess for reducing contact with the reduced diameter portion is formed in the second leg, and a first recess for reducing contact with the reduced diameter portion is formed in the first leg, and the second projection is formed. 2. The telescopic shaft according to claim 1, wherein a larger number of the first recesses than the second recesses are formed so that an area is larger than the first projection area.

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