JP2012126382A - Slide rail device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a slide rail device having a lower rail having a uniform cross section, an upper rail having a uniform cross section and slidably fitted to the lower rail, and balls inserted between the lower rail and the upper rail, and hardly causing the inward shrinkage deformation of the upper rail.SOLUTION: In the slide rail device, a cross-sectional shape of an upper rail in a free state is set in such a manner that, when the inner face of a connection corner between an upper-rail upper wall and a pair of upper-rail side walls of the upper rail is regarded as a virtual deformation rotation center in deformation of the upper rail upon application of a vertical load on the upper rail, an outward intersection angle α between a line that connects the virtual deformation rotation center and the center of a lower ball, and a tangential line on an upper-rail lower ball contact part of the upper rail with the lower ball is close to 90° as much as possible even if there are dimensional variations based on manufacturing errors of the upper rail, and is surely smaller than 90°.

Description

  The present invention relates to a slide rail device that adjusts the longitudinal position of a vehicle seat.

  The slide rail device is composed of a lower rail fixed to the vehicle floor surface and an upper rail slidably fitted to the lower rail and fixed to the seat side, and a ball that reduces sliding resistance between the rails. (Steel balls) are generally interposed. The upper rail and the lower rail are made of a metal material (generally an iron-based material) having a uniform cross section.

  In one aspect, the lower rail of the slide rail device has, in cross-sectional shape, a lower bottom wall, a pair of lower side walls extending upward from the inner and outer ends of the lower bottom wall, and the pair of lower bottom walls and a pair of lower side walls. A pair of lower lower ball contacts R that connect the upper rail and the pair of upper side walls extending in the lower rail from between the upper upper wall and the pair of lower upper walls of the lower rail in the same cross-sectional shape. A pair of ball receiving upper walls extending outwardly from the lower ends of the pair of upper side walls, and a pair facing the lower lower ball contact R portion of the lower rail formed below the pair of ball receiving upper walls. And an upper lower ball contact portion. A lower ball is inserted between the pair of lower lower ball contact R portions of the lower rail and the pair of upper lower ball contact portions of the upper rail to reduce sliding resistance (increase slidability).

Japanese Patent No. 4230945

  In such a slide rail device, when a vertical load is applied between the upper rail and the lower rail due to the weight of the seated person, a large deformation force acts particularly on the upper rail, and the pair of upper side walls are deformed outward (that is, the pair of the rails). The outer side wall of the upper side may be separated from each other). However, according to the present inventors, the outward opening deformation of the pair of upper side walls of the upper rail deteriorates the slidability.

  Further, when a force is applied between the upper rail and the lower rail due to the weight of the seated person, a large force is applied to the contact portion with the ball, and as a result, the rail may be indented by the ball. When the indentation is given, the rolling property of the ball is obviously impaired. Therefore, it is preferable to make the shape as indented as possible. For this reason, conventionally, the R diameter of the ball and the R diameter of the ball contact portion of the rail are set to be the same. That is, if the R diameter of the ball and the R diameter of the ball contact portion of the rail are the same, the surface pressure applied to the rail side is geometrically the lowest, and there is little risk of indentation. However, the present inventor, when the R diameter of the ball and the R diameter of the ball contact portion of the rail are designed to be the same diameter, the ball rolling performance is independent of the presence or absence of the impression (separately from the problem of the impression). It has been found that the slide stroke of the rail may be unstable.

  In the slide rail device, the inventor considers the inner surface of the connection corner portion between the upper wall of the upper rail and the pair of upper side walls as a virtual deformation rotation center when the upper rail is deformed by applying a vertical load to the upper rail. Based on the center of rotation, a condition that does not cause outward deformation is created.

  That is, the present invention relates to a slide rail device having a lower rail having a uniform cross section, an upper rail having a uniform section slidably fitted on the lower rail, and a ball inserted between the lower rail and the upper rail. In a cross-sectional shape, a lower bottom wall, a pair of lower side walls extending upward from inner and outer end portions of the lower bottom wall, and a pair of lower lower ball contact R portions connecting the pair of lower bottom walls and the pair of lower side walls; The upper rail has, in cross-sectional shape, an upper upper wall, a pair of upper side walls extending into the lower rail from between the pair of lower upper walls of the lower rail, and an upper outer side from a lower end portion of the pair of upper side walls. A pair of extended ball receiving upper walls and the lower lower ball contact R portion of the lower rail formed below the pair of ball receiving upper walls. A pair of upper lower ball contact portions; a pair of the lower lower ball contact R portions of the lower rail; and a pair of the lower lower ball contact portions of the upper rail; When the inner surface of the connecting corner portion between the upper upper wall and the pair of upper side walls is set as a virtual deformation rotation center when the upper rail is deformed by applying a vertical load to the upper rail, the virtual deformation rotation center and the lower ball center And the outward crossing angle α between the lower ball and the tangent of the upper lower ball contact portion of the upper rail is as close to 90 ° as possible even if there is a dimensional variation based on the manufacturing error of the upper rail. It is characterized in that the cross-sectional shape in the free state of the upper rail is set so as to be always less than 90 °.

  The cross-sectional shape of the upper rail in the free state is preferably set so that the outward crossing angle α is 80 ° to less than 90 °, preferably 80 ° to 88 °.

  The present inventor has also investigated the cause of the deterioration of the slidability due to the indentation of the ball. As a result, if the R diameter of the ball and the R diameter of the ball contact portion of the rail are designed to be the same, the rail side Due to a manufacturing error, there is a combination in which the R diameter of the ball contact portion of the rail is smaller than the R diameter of the ball. In this combination, the ball and the ball contact portion of the rail come into contact at two points. A conclusion was reached that gender is impaired. As is well known, the dimensional accuracy and hardness of a ball (steel ball) are very high, and the dimensional error hardly affects the rolling performance. The cross-section arc length (angle) of the ball contact R portion on the rail side is generally large on the lower rail side and short on the upper rail side, and therefore the influence of the ball contact R portion shape on the lower rail side is large.

  In another aspect, the present invention provides a slide rail device comprising a lower rail having a uniform cross section, an upper rail having a uniform cross section slidably fitted to the lower rail, and a ball inserted between the lower rail and the upper rail. The lower rail includes a lower bottom wall, a pair of lower side walls extending upward from the inner and outer ends of the lower bottom wall, and a pair of lower upper walls extending from the upper ends of the pair of lower side walls toward the center of the rail in the cross-sectional shape. The lower bottom wall and the pair of lower side walls are connected by a pair of lower lower ball contact R portions, and the pair of lower side walls and the lower upper wall are connected by a pair of lower upper ball contact R portions. The upper rail has, in cross-sectional shape, an upper upper wall, a pair of upper side walls extending into the lower rail from between the pair of lower upper walls of the lower rail, and the pair of upper rails. A pair of ball receiving upper walls extending outward from the lower end of the side wall of the upper and lower sides of the upper and lower ball contact R portions of the lower rail. An opposing upper upper ball contact portion and upper lower ball contact portion are formed, and an upper ball is inserted between the lower upper ball contact R portion of the lower rail and the upper upper ball contact portion of the upper rail, and the lower rail. A lower ball is inserted between the lower ball contact R portion of the lower rail and the upper lower ball contact portion of the upper rail, and the diameter of the lower ball contact R portion of the lower rail is larger than the diameter of the lower ball. Is set larger, and the diameter of the lower ball contact R portion of the lower rail is larger than the diameter of the upper ball. That it is constant, it is characterized in. The “R portion” means a circular arc portion formed with a specific curvature. The curvature includes not only the curvature of a circle but also the curvature of an ellipse. Further, “inside / outside” means the vehicle width direction, and “outside” means the outside direction from the center of the rail cross section.

  Both the upper upper ball contact portion and the upper lower ball contact portion of the upper rail can be flat, but at least the upper ball contact portion is preferably a ball contact R portion. Because the ratio of the reaction force due to the deflection of the rail (ball receiving upper wall) and the input that enters the ball receiving upper wall via the upper ball is larger than the reaction force due to the lower ball, the upper ball contact portion is flat. It is preferable that the contact R portion has a lower surface pressure. The diameter of the upper ball contact R portion is preferably set larger than the diameter of the upper ball for the same reason that the diameter of the ball contact R portion of the lower rail is preferably larger than the ball diameter.

  The upper lower ball contact portion of the upper rail is also preferably a ball contact R portion rather than a flat surface, and at this time, the diameter of the ball contact R portion is preferably larger than the lower ball diameter.

When the lower ball diameter is r1, the upper ball diameter is r2, the diameter of the lower ball contact R portion of the lower rail is R1, and the diameter of the lower upper ball contact R portion is R2, R1 ≧ 1.1r1, R2 ≧ 1.1r2 More preferably, R1 ≧ 1.2r1 and R2 ≧ 1.2r2. Considering the dimensional error in manufacturing the rail, it was confirmed that when R1 and R2 are smaller than this condition, the surface pressure of the ball contact portion is lowered but the rolling property is inferior (combination occurs).
On the other hand, the upper limit of R1 and R2 is set so that the surface pressure of the contact portion with the ball is not more than the allowable surface pressure in consideration of the rail material.

  According to the slide rail device of the present invention, the pair of ball receiving upper walls of the upper rail can be reliably deformed inwardly (that is, inwardly contracting deformation in which the pair of ball receiving upper walls approach each other). Further, it is possible to prevent the deterioration of the slidability due to the outward deformation.

It is a longitudinal section showing one embodiment of a slide rail device by the present invention. It is a fragmentary sectional view which shows the detailed shape of the upper rail of the slide rail apparatus by this invention. It is the graph which investigated the relationship between a ball contact R part diameter / ball diameter, and a contact surface pressure.

  FIG. 1 shows an embodiment of a slide rail device 10 according to the present invention. The slide rail device 10 includes a lower rail 20 fixed to the vehicle floor, an upper rail 30 fixed to the seat, a lower ball 40 inserted between the lower rail 20 and the upper rail 30 fitted so as to be slidable relative to each other, and an upper rail 30. It has a ball 50 and has a symmetrical shape in a cross section orthogonal to the extension direction of the rail. The lower ball 40 has a larger diameter than the upper ball 50. As is well known, the slide rail device 10 has a pair of left and right in the state of being attached to the vehicle and is provided with a lock mechanism and the like. However, the present embodiment is based on the uniform cross-sectional shape of the lower rail 20 and the upper rail 30. Thus, only the cross-sectional shape will be discussed in the following description. In the following description, “inside / outside”, “left / right” are inside / outside in the vehicle width direction, left / right, “outside” is the direction outward from the center of the rail cross section, and “R part” is a section formed with a specific curvature. It means an arc part.

  The lower rail 20 includes a horizontal lower bottom wall 21 that is fixed to the vehicle floor, a pair of lower side walls 22 that extend upward from the inner and outer ends of the lower bottom wall 21, and upper ends of the pair of lower side walls 22. A pair of lower upper walls 23 extending in the center of the rail from the center are formed, and a pair of lower inner walls 24 extending downward are formed on the rail center side of the pair of lower upper walls 23.

  The lower bottom wall 21 and the pair of lower side walls 22 are connected by a lower ball contact R portion 25, and the pair of lower side walls 22 and the lower upper wall 23 are connected by a lower upper ball contact R portion 26. .

  The upper rail 30 is connected to the left and right horizontal upper upper wall 31 fixed to the seat side, and a pair of upper side walls 32 extending from the pair of lower inner side walls 24 of the lower rail 20 into the lower rail 20. , And a pair of ball receiving upper walls 33 extending outward from the lower ends of the pair of upper side walls 32.

  The ball receiving upper wall 33 is formed with an upper lower ball contact R portion 34 facing the lower ball contact R portion 25 of the lower rail 20 below the ball receiving upper wall 33, and opposed to the lower upper ball contact R portion 26 of the lower rail 20. An upper upper ball contact R portion 35 is formed, and the upper lower ball contact R portion 34 and the upper upper ball contact R portion 35 are connected by a vertical connection wall 36.

  The upper lower ball contact R portion 34 and the upper upper ball contact R portion 35 hold (insert) the lower ball 40 and the upper ball 50 between the lower lower ball contact R portion 25 and the lower upper ball contact R portion 26, respectively. Is marked with R. However, the region (angle) forming R is smaller than the lower lower ball contact R portion 25 and the lower upper ball contact R portion 26. The lower ball contact R portion 25 and the lower upper ball contact R portion 26 are formed over 90 °, whereas the R formation region (angle) of the upper lower ball contact R portion 34 is particularly small (small). It is possible to replace it with a plane.

  The diameter R1 of the lower lower ball contact R portion 25 and the diameter R1 'of the upper lower ball contact R portion 34 are both set larger than the diameter r1 of the lower ball 40. Similarly, the diameter R2 of the lower upper ball contact R portion 26 and the diameter R2 'of the upper upper ball contact R portion 35 are both set larger than the diameter r2 of the upper ball 50. The diameter R1 and the diameter R1 'can be the same diameter or slightly different. Similarly, the diameter R2 and the diameter R2 'can be the same diameter or slightly different.

  FIG. 2 is a view for explaining a preferred shape of the upper rail in a free state. The inner surface of the connecting corner portion between the upper upper wall 31 and the pair of upper side walls 32 of the upper rail 30 becomes a virtual deformation rotation center X when the vertical load is applied to the upper rail 30 and the upper rail 30 is deformed. The cross-sectional shape of the upper rail 30 is, in a free state, a line segment Y connecting the virtual deformation rotation center X and the center of the upper ball 50, and a tangent Z of the lower ball 40 and the upper lower ball contact R portion 34 of the upper rail 30. The outward crossing angle α is set to 80 ° to less than 90 °. A more preferable crossing angle α is 80 ° to 88 °. By setting in this way, the lower balls 40 can surely cause the pair of upper side walls 32 of the upper rail 30 to be deformed inward (that is, the inner side deformations of the pair of upper side walls 32 approaching each other). Can do. The outward opening deformation in the direction opposite to the inward shrinkage deformation may interfere with slidability.

  In other words, the upper rail 30 has the highest load resistance theoretically in a free state in which the line segments Y and Z are orthogonal (90 °). However, if the shape is designed so that the line segments Y and Z are orthogonal to each other, when the shape varies due to manufacturing errors, the outward crossing angle α becomes larger than 90 °, and as a result, outward deformation tends to occur. This will adversely affect slidability. In the present embodiment, the shape is set so that the outward crossing angle α is always less than 90 ° even if there is a manufacturing error. The shape setting of the upper rail 30 in the free state is characterized in that the diameter R of the ball contact R portions 25, 26, 34, 35 described below is set larger than the diameter r of the lower ball 40 and the upper ball 50. It has nothing to do with it.

  FIG. 3 shows the change in contact surface pressure at the ball contact portion when the ratio of the diameter r of the upper ball 50 or the lower ball 40 and the diameter R of the ball contact R portions 25, 26, 34, and 35 is changed. It is a graph. From this graph, it was found that there is a boundary where the contact surface pressure changes abruptly between R / r = 1.1 and 1.2. Considering this fact and the fact that the diameter of the R portion of the lower rail 20 and the upper rail 30 varies due to manufacturing errors, it is preferable that R ≧ 1.1r, more preferably, R ≧ 1.2r, so that the ball contact R portion 25, Regardless of variations in the diameter R of 26, 34, and 35, the rolling performance of the lower ball 40 and the upper ball 50 can be ensured. On the other hand, the upper limit of the diameter R (R1 and R2) is set so that the surface pressure of the contact portion with the ball is less than the allowable surface pressure in consideration of the rail material.

  In the above embodiment, not only the lower lower ball contact R portion 25 and the lower upper ball contact R portion 26 but also the upper lower ball contact R portion 34 and the upper upper ball contact R portion 35 are R portions. Of the contact R portion 34 and the upper upper ball contact R portion 35, the upper lower ball contact R portion 34 may be a flat surface. On the other hand, since the upper upper ball contact R portion 35 has a function of bending the ball receiving upper wall 33 via the lower ball 40, the upper portion of the ball contact R portion 35 has a lower surface pressure than the flat surface as in the embodiment. Is preferred.

DESCRIPTION OF SYMBOLS 10 Slide rail apparatus 20 Lower rail 21 Lower bottom wall 22 Lower side wall 23 Lower upper wall 24 Lower inner wall 25 Lower lower ball contact R part 26 Lower upper ball contact R part 30 Upper rail 31 Upper upper wall 32 Upper side wall 33 Ball receiving upper wall 34 Upper lower ball contact R portion 35 Upper upper ball contact R portion 36 Vertical connection wall 40 Lower ball 50 Upper ball

Claims (6)

In a slide rail device comprising a lower rail having a uniform cross section, an upper rail having a uniform cross section slidably fitted to the lower rail, and a ball inserted between the lower rail and the upper rail,
The lower rail has, in cross-sectional shape, a lower bottom wall, a pair of lower side walls extending upward from the inner and outer ends of the lower bottom wall, and a pair of lower lower ball contacts that connect the pair of lower bottom walls and the pair of lower side walls. Having an R portion,
The upper rail has, in cross-sectional shape, a pair of upper upper walls, a pair of upper side walls extending into the lower rail from between the pair of lower upper walls of the lower rail, and a pair of balls extending outward from the lower ends of the pair of upper side walls. A receiving upper wall and a pair of upper lower ball contact portions formed below the pair of ball receiving upper walls and facing the lower lower ball contact R portion of the lower rail;
A lower ball is inserted between the pair of lower lower ball contact portions R of the lower rail and the pair of upper lower ball contact portions of the upper rail, and the upper upper wall of the upper rail and the pair of upper side walls. When the inner surface of the connecting corner is used as a virtual deformation rotation center when a vertical load is applied to the upper rail and the upper rail is deformed, a line segment connecting the virtual deformation rotation center and the lower ball center, and the upper of the lower ball and the upper rail The upper rail is free so that the outward crossing angle α with the tangent of the lower ball contact portion is as close as possible to 90 ° and always less than 90 ° even if there is a dimensional variation due to manufacturing errors of the upper rail. The cross-sectional shape in the state is set,
A slide rail device characterized by. 2. The slide rail device according to claim 1, wherein the cross-sectional shape is set so that the outward crossing angle α is 80 ° to less than 90 ° in a free state of the upper rail. 3. The slide rail device according to claim 1, wherein the lower rail further connects a pair of lower upper walls extending from the upper ends of the pair of lower side walls toward the center of the rail, and the pair of lower upper walls and the lower upper wall. A pair of lower upper ball contacts R that
The upper rail further includes an upper upper ball contact portion formed above the pair of ball receiving upper walls.
A slide rail device in which upper balls are respectively inserted between a pair of the lower upper ball contact portions of the lower rail and a pair of the upper upper ball contact portions of the upper rail. 4. The slide rail device according to claim 3, wherein at least the upper ball contact portion of the upper upper ball contact portion and the upper lower ball contact portion of the upper rail is formed as an upper ball contact R portion. 5. The slide rail device according to claim 4, wherein a diameter of the upper ball contact R portion is larger than a diameter of the upper ball. 6. The slide rail device according to claim 4, wherein the upper lower ball contact portion of the upper rail is formed as an upper lower ball contact R portion, and the diameter of the upper lower ball contact R portion is larger than the diameter of the lower ball. Slide rail device.

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