JP2019026028A - Seat sliding apparatus - Google Patents

Abstract

To reduce a load applied to bend a screw shaft to prevent breakage thereof while accepting falling down of a bracket at the excessive axial force action of the screw shaft in a seat sliding apparatus.SOLUTION: A seat sliding apparatus is equipped with: a lower rail; a slidable upper rail; a screw shaft 4: and a gear box having a gear screwing together with the screw shaft 4. A front side bracket 9 fixing the front end part of the screw shaft 4 to the lower rail has a bottom wall part 19, a vertical wall part 20 on which an insertion hole 21 is formed, and a nut 22 screwing together with the front end of the screw shaft 4 bush-inserted in the insertion hole 21. Besides, the insertion hole 21 is elongation-formed like a long hole from the end of the bottom wall part 19 side of the nut 22 to the bottom wall part 19 side so that the insertion hole 21 protrudes from the end of the bottom wall part 19 side of the nut 22 in the front view of the vertical wall part 20.SELECTED DRAWING: Figure 6

Description

  The present invention relates to a vehicle seat slide device, and more particularly to an improvement of a slide rail as a main element of an electric seat slide device called a power seat.

  As this type of seat slide device, for example, those described in Patent Documents 1 and 2 have been proposed.

  In the techniques disclosed in these Patent Documents 1 and 2, the lower rail fixed to the vehicle body floor and the upper that is attached to the seat that is subject to front-rear position adjustment and is slidable in the longitudinal direction with respect to the lower rail. A gear including a rail, a screw shaft supported by one of the lower rail and the upper rail, a worm wheel engaged with the screw shaft, and a worm meshing with the worm wheel, and a gear fixed to the other rail And a box as a basic structure.

  Then, both ends of the screw shaft are supported at both ends by one rail via a bracket bent in an L shape, for example. In particular, on the front end side of the screw shaft, two sets of L-shaped brackets are abutted with each other in order to improve support strength, and the front end of the screw shaft is inserted into holes formed in these brackets. After being inserted and supported, it is fastened and fixed with a nut. If one of the above two brackets is a support bracket, the other functions as a reinforcing bracket that supports the support bracket.

  Moreover, the nut screwed to the front end of the screw shaft serves to bear the axial force applied to the screw shaft. For example, at the time of a collision from the front of the vehicle, a pulling force in the direction in which the screw shaft is about to come out from a pair of brackets acts on the two, and the pulling force is applied via a nut screwed to the screw shaft. Are input to a set of brackets.

JP 2007-50715 A JP2013-241174A

  However, in the conventional techniques represented by Patent Documents 1 and 2, even if two sets of brackets are adopted on the front end side of the screw shaft, for example, as described in FIG. In addition, when an excessive tensile force acts on the screw shaft, the vertical wall portion of the bracket may still fall. In addition, the bending force of the screw shaft accompanying the above-described tilting is increased by the amount that the brackets are substantially overlapped, and there is a possibility that the screw shaft is still broken along with the tilting of the vertical wall portion.

  The present invention has been made paying attention to such a problem, and reduces the load to bend the screw shaft while allowing the vertical wall portion of the bracket to fall when an excessive input action is applied to the screw shaft. Thus, the present invention provides a structure that can prevent breakage of the screw shaft.

  The present invention includes a lower rail disposed along a front-rear direction on a vehicle floor surface, an upper rail that is slidable in a longitudinal direction with respect to the lower rail and on which a seat is assembled, and a longitudinal direction of both the rails. A screw shaft that is disposed and supported by one of the lower rail and the upper rail, and a gear that is provided on the other rail of the lower rail and the upper rail and is screwed to the screw shaft. And at least a front end portion of the screw shaft is fixedly supported on the one rail via an L-shaped bracket.

  In addition, the bracket includes a bottom wall portion fixed to the one rail, a vertical wall portion formed with an insertion hole standing from the bottom wall portion and into which the screw shaft is inserted, and the insertion hole. And a load receiving member that is fixed to the front end of the screw shaft inserted into the front wall and sits on a front surface of the vertical wall portion.

  And, in the front view of the vertical wall portion, the insertion hole is located on the bottom wall portion side of the load receiving member so that the insertion hole protrudes from the end portion on the bottom wall portion side of the load receiving member. It is formed to extend further to the bottom wall portion side than the end portion.

  In this case, it is preferable that the insertion hole has a long hole shape in which a diameter through which the front end portion of the screw shaft can be inserted is a short diameter and a long diameter direction is directed in the vertical direction of the vertical wall portion. .

  Similarly, it is preferable that a portion of the front wall surface of the vertical wall portion on the bottom wall portion side with respect to the center position of the screw shaft is one step lower than a portion on which the load receiving member is seated. It is assumed that the clearance surface is offset with a step, and a gap is set between the clearance surface and the end portion on the bottom wall portion side of the load receiving member.

  Further preferably, the load receiving member is a nut that is screwed onto the screw shaft.

  In addition, when the bracket is also used as a stopper when the seat is most advanced, for example, when the holder that houses the gear mechanism is abutted against the vertical wall portion of the bracket when the seat is most advanced, the screw shaft is inserted through the bracket. The insertion hole of the vertical wall portion may be fitted with an elastic holding member that holds the screw shaft from both the front and back sides while holding the screw shaft.

  According to the present invention, even if an excessive tensile force acts on the screw shaft and the vertical wall portion of the support bracket falls down, the insertion hole formed in the vertical wall portion of the support bracket has a substantially long hole shape. As a result, at least the end portion on the bottom wall portion side of the load receiving member matches a part of the insertion hole, and is not in direct contact with the vertical wall portion of the support bracket. For this reason, the load to bend the screw shaft is reduced, and breakage of the screw shaft can be prevented in advance.

  Further, in addition to the insertion hole formed in the vertical wall portion of the support bracket having a substantially long hole shape, a part of the front side surface of the vertical wall portion is further lowered. When the clearance surface is offset with a step and a clearance is set between the clearance surface and the end of the load receiving member on the bottom wall side, the load to bend the screw shaft is further increased. As a result, the effect of preventing the breakage of the screw shaft becomes more remarkable.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows 1st Embodiment of the seat slide apparatus which concerns on this invention, and sectional drawing in the state which has an upper rail in a retreat limit position. Sectional drawing of the state which has the upper rail shown in FIG. 1 in a forward limit position. The expanded sectional view along the AA line of FIG. The enlarged view of the principal part of FIG. FIG. 5 is a further enlarged view around the front bracket shown in FIG. 4. The front enlarged view which looked at the front bracket shown in FIG. 5 from the left side. The expansion perspective view of the bush with which the vertical wall part of the front side bracket shown in FIG. 5 is mounted | worn. FIG. 6 is a diagram showing a second embodiment of the seat slide device according to the present invention, and is an enlarged view of a portion equivalent to FIG. FIG. 9 is an explanatory diagram when an excessive input to the rear is applied to the front bracket shown in FIG. 8 via a screw shaft due to a collision, and (A) is an explanatory diagram before an input is applied to the vertical wall portion of the front bracket. (B) is explanatory drawing when the vertical wall part falls down, (C) is further explanatory drawing when the vertical wall part falls down. FIG. 6 is a diagram showing a third embodiment of the seat slide device according to the present invention, and is an enlarged view of a portion equivalent to FIG. 5. FIG. 6 is a view showing a fourth embodiment of the seat slide device according to the present invention, and is an enlarged view of a portion equivalent to FIG. 5.

  1 to 7 show a more specific first embodiment for carrying out the seat slide device according to the present invention. In particular, FIG. 1 shows the longitudinal direction of one slide rail 1 which is a main element of the seat slide device. FIG. 6 is a cross-sectional view taken along the line A and shows a state in which the upper rail 3 is most retracted relative to the lower rail 2 and is in the retreat limit position. 2 shows a state in which the upper rail 3 of FIG. 1 is most advanced to the forward limit position, and FIG. 3 is an enlarged sectional view taken along the line AA of FIG. Further, FIG. 4 shows an enlarged view of the main part of FIG.

  As is well known, in an electric seat slide device called a power seat, a pair of left and right slide rails 1 shown in FIGS. 1 to 3 is used as a pair so that each longitudinal direction is along the vehicle longitudinal direction, and It is arranged on the vehicle floor surface (floor surface) so as to be parallel to each other at a predetermined distance. Accordingly, the left side of FIGS. 1 and 2 is the front side of the vehicle, and the right side of FIG.

  The slide rail 1 is schematically composed of a lower rail 2 arranged along the front-rear direction on the floor surface of the vehicle, an upper rail 3 assembled to the lower rail 2 so as to be slidable in the longitudinal direction, and the upper rail 3 in the upper rail 3. A long male screw-like screw shaft 4 arranged along the longitudinal direction and a gear box 5 as a gear mechanism externally attached to the screw shaft 4 are configured.

  The lower rail 2 is fixed to the floor surface of the vehicle via foot brackets (not shown), for example, at two positions in the longitudinal direction. On the other hand, the upper rail 3 is fixed to a frame of a seat (seat cushion) (not shown). As shown in FIG. 3, the lower rail 2 has a substantially deformed channel shape with an open upper surface, and a flange portion 2a is bent downward from the upper opening edge, while the upper rail 3 has a lower surface. The open section has a substantially deformed channel shape, and a flange portion 3a is bent upward from the lower opening edge. And both flange parts 2a and 3a have overlapped.

  As shown in FIG. 3, a slide guide member 6 is interposed between the lower rail 2 and the flange portion 3 a on the upper rail 3 side, so that the upper rail 3 can slide smoothly with respect to the lower rail 2. ing. The slide guide member 6 has a known structure in which a plurality of steel balls 6b are held above and below the retainer 6a. For example, the slide guide member 6 is provided at two positions before and after the overlapping range in the longitudinal direction of the lower rail 2 and the upper rail 3. It is interposed and is not shown in FIGS.

  The front end portion of the screw shaft 4 is fixedly supported by an L-shaped front bracket 9 fixed to the front end portion of the lower rail 2 by a rivet 8 together with the reinforcing plate 7. On the other hand, the rear end portion of the screw shaft 4 is fixedly supported by a rear bracket 12 which is fixed to the rear end portion of the lower rail 2 by a bolt 11 together with the reinforcing plate 10. The rear end portion of the screw shaft 4 is directly fixed to the rear bracket 12 and is integrally fixed by, for example, welding. As a result, the screw shaft 4 is supported at both ends by the lower rail 2 through the front bracket 9 and the rear bracket 12 so as not to rotate. The details of the front bracket 9 will be described later.

  As shown in FIG. 4, the gear box 5 has a case 13 corresponding to the box body accommodated in a holder 14, and the holder 14 is fixed to the upper rail 3 by a rivet 16 together with a cover 15. A worm gear including a worm 17 and a worm wheel 18 meshing with the worm 17 is accommodated in the case 13. The inner peripheral surface of the worm wheel 18 is an internal thread portion that meshes with the external thread portion of the screw shaft 4. Therefore, when the worm 17 is rotationally driven in the forward or reverse direction by a motor (not shown), the worm wheel 18 meshing with the worm 17 rotates. Due to the screwing action based on the rotation of the worm wheel 18, the upper rail 3 slides in the forward or backward direction with respect to the lower rail 2.

  FIG. 5 shows a further enlarged view around the front bracket 9 shown in FIG. The front bracket 9 is formed by bending a metal plate having a predetermined thickness into an L shape. The front bracket 9 has a bottom wall portion 19 that is in close contact with the lower rail 2 and functions as a stopping point by the rivet 8, and a vertical wall portion 20 that stands up at a right angle from the bottom wall portion 19. An insertion hole 21 penetrating in the thickness direction is formed in the vertical wall portion 20. A front end portion of the screw shaft 4 is inserted into the insertion hole 21 via a bush 23 described later, and a nut 22 as a load receiving member is screwed. Accordingly, the front end portion is supported by the front bracket 9 in a manner that a predetermined tension is applied in the axial direction of the screw shaft 4. It should be noted that other members may be used instead of the nut 22 as the load receiving member as long as the function of preventing the screw shaft 4 from coming off is exhibited.

  Further, the vertical wall portion 20 has a lower half on the base side close to the bottom wall portion 19 and an upper half on the upper side offset from each other in the plate thickness direction, and on the front side of the vertical wall portion 20, A flank 20a is formed with a predetermined step which is one step lower on the lower half side than the upper surface side on which the nut 22 is to be seated.

  FIG. 6 is an enlarged front view of the front bracket 9 shown in FIG. 5 as viewed from the left side. As shown in FIG. 6, the insertion hole 21 formed in the vertical wall portion 20 has a long hole shape that is long in the vertical direction. Has become. That is, the insertion hole 21 has a short diameter that is slightly larger than the diameter of the screw shaft 4 so that the screw shaft 4 can be inserted, and the long diameter direction perpendicular to the short diameter direction is the vertical direction (the bottom wall portion 19 has It is formed as a long hole that points in the direction of heading.

  A bushing 23 as a holding member made of a rubber-based elastic body as shown in FIG. 7 is fitted into the insertion hole 21. The bush 23 includes an oval cylindrical portion 23a that fits into the long hole-shaped insertion hole 21, a substantially semicircular flange portion 23b that is integrally formed on one end side of the cylindrical portion 23a, and a cylindrical portion. A rectangular flange portion 23c formed integrally with the other end side of 23a. A shaft hole 23d through which the screw shaft 4 can be inserted is formed in the cylindrical portion 23a.

  Then, as shown in FIG. 5, both flange portions 23 b are positioned such that one flange portion 23 b is located on the front side of the vertical wall portion 20 and the other flange portion 23 c is located on the back side of the vertical wall portion 20. 23c, the cylindrical wall portion 23a of the bush 23 is fitted and held in the insertion hole 21 so that the vertical wall portion 20 is sandwiched from both the front and back sides. As a result, as shown in FIG. 5, the nut 22 screwed into the front end portion of the screw shaft 4 is indirectly seated on the vertical wall portion 20 via the flange portion 23 b of the bush 23. .

  Here, as is clear from FIG. 6, when attention is paid to the relationship between the nut 22 as the load receiving member and the insertion hole 21 in a front view of the front bracket 9, the long insertion hole 21 is formed from the lower end of the nut 22. The long diameter of the insertion hole 21 is set so that a part of the insertion hole 21 protrudes. That is, in FIG. 6, the insertion hole 21 having a long hole shape extends further to the bottom wall portion 19 side than the lower end of the nut 22 (here, for convenience, the lowermost point P1 of the flange attached to the nut 22). An extension is formed.

  Further, as is apparent from FIG. 5, the portion below the center of the screw shaft 4 between the vertical wall portion 20 of the front bracket 9 and the nut 22, more specifically, the diameter of the screw shaft 4. In a portion below the corresponding portion, a gap G corresponding to the offset amount between the lower half portion and the upper half portion of the vertical wall portion 20 is secured between the nut 22 and the cylindrical portion 23a of the bush 23. Will be.

  Note that the general part of the screw shaft 4 (the part screwed with the internal threaded part of the inner periphery of the worm wheel 18) has an irregular cross section as shown in FIG. As shown in FIGS. 5 and 6, the portion supported by the side bracket 12 has a circular shape slightly smaller in diameter than the general portion.

  Therefore, in the seat slide device configured as described above, as described above, the worm gear composed of the worm 17 and the worm wheel 18 rotates in the forward rotation direction or the reverse rotation direction, so that the upper rail is moved with respect to the lower rail 2. 3 slides in the forward or backward direction.

  When the upper rail 3 slides to the retreat limit position, as shown in FIG. 1, the holder 14 that accommodates the gear box 5 contacts the rear bracket 12 and functions as a so-called mechanical stopper. On the other hand, when the upper rail 3 slides to the forward limit position, as shown in FIGS. 2 and 4, the holder 14 that houses the gear box 5 abuts on the front bracket 9 and functions as a so-called mechanical stopper. A bush 23 is attached to the front bracket 9, and when the holder 14 that accommodates the gear box 5 is brought into contact with the flange portion 23 c of the bush 23, a cushioning effect by the bush 23 is exerted, and the hitting between the metals is performed. Sound generation is also prevented.

  Here, FIG. 8 shows a second embodiment of the seat slide device according to the present invention when the bush 23 shown in FIG. 5 is eliminated.

  In the second embodiment shown in FIG. 8, when an excessive input corresponding to the pulling force in the direction of arrow B is applied to the screw shaft 4 at the time of a vehicle collision, for example, the load is applied by the nut 22 that functions as a load receiving member. The load is applied to the vertical wall portion 20 of the front bracket 9 after being loaded.

  The vertical wall portion 20 to which such an excessive input is loaded causes the screw shaft 4 to move in the direction of arrow B, so that the screw shaft 4 is pressed against the upper end surface of the insertion hole 21, and FIG. As shown, a fall occurs between the root portion and the contact point P2 of the nut 22. At this time, since the flange lower end P1 of the nut 22 is not in contact with the vertical wall portion 20 by the gap G, the force for bending the screw shaft 4 inserted and supported by the vertical wall portion 20 can be reduced. Furthermore, as shown in FIG. 9C, even when the vertical wall portion 20 is greatly tilted, the flange lower end P <b> 1 of the nut 22 enters the insertion hole 21 to try to bend the screw shaft 4. The power can be reduced.

  That is, in the second embodiment shown in FIG. 8, as shown in FIG. 6, in the front view of the front bracket 9, a long hole formed in the vertical wall portion 20 from the flange lower end P <b> 1 of the nut 22. Since the insertion hole 21 is formed so as to extend in the major axis direction so that a part of the insertion hole 21 protrudes, even if the vertical wall portion 20 falls down as shown in FIG. The flange lower end P <b> 1 does not directly contact the vertical wall portion 20. As a result, the bending moment applied to the screw shaft 4 is relaxed, the breaking (breaking) strength of the screw shaft 4 is relatively improved, and the conventional breakage of the screw shaft 4 can be prevented.

  As a result of experiments conducted by the present inventors under the second embodiment, it has been found that the breaking strength of the screw shaft 4 is improved by 60% or more compared to the conventional type.

  Moreover, as shown in FIG. 5, since the gap G is preset between the flange lower end P1 of the nut 22 and the vertical wall portion 20, the point where the nut 22 and the vertical wall portion 20 contact during deformation is Since the contact point P2 does not change, the contact point becomes stable, the bending moment applied to the screw shaft 4 can be reduced and stabilized, and the breaking (breaking) strength of the screw shaft 4 can be further improved. This is further advantageous in preventing the screw shaft 4 from being broken.

  As described above, the first embodiment shown in FIG. 5 differs from the second embodiment shown in FIG. 8 only in that a bush 23 is added. The bush 23 is formed of a rubber-based elastic body. In this case, for example, as shown in FIG. 9, when the vertical wall portion 20 of the front bracket 9 falls down, the second embodiment shown in FIG. 8 is also used in the first embodiment shown in FIG. It can be easily understood that the same behavior as that of the embodiment is performed. Therefore, also in the first embodiment shown in FIG. 5, the same effect as in the second embodiment shown in FIG. 8 is obtained.

  FIGS. 10 and 11 are views showing third and fourth embodiments of the seat slide device according to the present invention, and the same reference numerals are given to the portions common to the first embodiment.

  In the third embodiment shown in FIG. 10, the lower half and the upper half of the vertical wall portion 20 </ b> A of the front bracket 9 are made thicker as apparent from the comparison with FIG. 5 which is the first embodiment. It differs only in that it is not offset in the direction.

  Further, in the fourth embodiment shown in FIG. 11, the lower half portion and the upper half portion of the vertical wall portion 20A of the front bracket 9 are made clear as compared with FIG. 5 which is the first embodiment. In addition to the fact that it is not offset in the plate thickness direction, it is different in that the bush 23 is abolished. Therefore, the screw shaft 4 is directly inserted into the insertion hole 21 formed in the vertical wall portion 20A.

  Also in these third and fourth embodiments, the relative positional relationship between the nut 22 and the insertion hole 21 in the front view of the front bracket 9 is the same as that of the first and second embodiments. As far as this point is concerned, the same effects can be obtained in the third and fourth embodiments.

  Here, in each of the above-described embodiments, the screw shaft 4 is supported at both ends on the lower rail 2 side, while the gear box 5 incorporating a worm gear is supported on the upper rail 3 side. Instead of this, for example, according to required specifications such as various layouts, the screw shaft 4 is supported at both ends on the upper rail 3 side, while the gear box 5 with a built-in worm gear is supported on the lower rail 2 side. Of course it is possible.

  Moreover, the shape of the long hole-shaped insertion hole 21 formed in the vertical wall part 20 shown in FIG. 6 is only an example, and if it is a shape that can exhibit an equivalent function, for example, a so-called daruma hole shape or other shapes May be.

2 ... Lower rail 3 ... Upper rail 4 ... Screw shaft 5 ... Gear box (gear mechanism)
DESCRIPTION OF SYMBOLS 9 ... Front side bracket 19 ... Bottom wall part 20 ... Vertical wall part 20a ... Flank 21 ... Insertion hole 22 ... Nut (load receiving member)
23 ... Bush (holding member)
G ... Gap

Claims (4)

A lower rail disposed along the front-rear direction on the vehicle floor;
An upper rail that is slidable in the longitudinal direction with respect to the lower rail and on which a seat is assembled;
A screw shaft that is arranged along the longitudinal direction of the two rails and is supported at both ends by either one of the lower rail and the upper rail;
A gear mechanism having a gear which is provided on the other rail of the lower rail and the upper rail and is screwed to the screw shaft;
With
A seat slide device in which at least a front end portion of the screw shaft is fixedly supported on the one rail via an L-shaped bracket,
The bracket is
A bottom wall fixed to the one rail;
A vertical wall portion that is formed with an insertion hole into which the screw shaft is inserted by standing from the bottom wall portion;
A load receiving member fixed to the front end of the screw shaft inserted into the insertion hole and seated on the front surface of the vertical wall portion;
Have
In the front view of the vertical wall portion, the insertion hole is an end portion of the load receiving member on the bottom wall portion side so that the insertion hole protrudes from an end portion of the load receiving member on the bottom wall portion side. The seat slide device is further extended to the bottom wall side.   The insertion hole has a long hole shape in which a diameter through which a front end portion of the screw shaft can be inserted is a short diameter and a long diameter direction is directed in an up and down direction of the vertical wall portion. The seat slide device according to 1.   Of the surface on the front side of the vertical wall portion, the portion on the bottom wall portion side with respect to the center position of the screw shaft is offset with a step so as to be one step lower than the portion on which the load receiving member is seated. The seat slide device according to claim 2, wherein a gap is set between the flank and an end of the load receiving member on the bottom wall portion side. The load receiving member is a nut screwed onto the screw shaft,
The insertion hole of the vertical wall part through which the screw shaft is inserted is fitted with an elastic holding member that holds the vertical wall part from both the front and back sides while holding the screw shaft. The seat slide device according to claim 3.

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