JP2017072235A - Gear box mechanism - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a gear box mechanism capable of accurately positioning and holding a gear member to divided housings, and easily assembling the gear member to the divided housings, in the gear box mechanism in which the gear member is rotatably supported between the pair of divided housings.SOLUTION: In a gear box mechanism in which a gear member is rotatably supported between a pair of divided housings, the gear member has a pair of relatively rotatable bearing bushes respectively on both end portions in an axial direction, at least one of the bearing bushes has a non-circular supported portion in parallel with a dividing direction of the pair of divided housings, and including a pair of main plane portions in parallel with each other through an axis of the bearing bush. One of the pair of divided housings has a bush supporting portion including a pair of first main receiving surfaces engaged with the pair of main plane portions of the bearing bushes for supporting the same.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a gear box mechanism that rotatably supports a gear member between a pair of divided housings.

  For example, this type of gearbox mechanism is used in a seat slide device that slides a vehicle seat in the front-rear direction. Specifically, the seat slide device has a lower rail that is fixed to the vehicle floor and an upper rail that is slidable with respect to the lower rail and is fixed to the lower surface of the seat. The lead screw extends on the lower rail in the vehicle front-rear direction. Is supported, and a gear box mechanism having a nut member (gear member) screwed to the lead screw is supported on the upper rail. The axial movement of the nut member relative to the upper rail is restricted, and the seat moves in the front-rear direction by rotationally driving the nut member forward and backward.

  Conventionally, such a gear box mechanism has rotatably supported a nut member between a pair of divided housings divided by a vertical dividing line parallel to the axis of the lead screw (Patent Document 1).

JP 2010-1226027 A

  However, in the conventional gear box mechanism, it is difficult to accurately (accurately) position the gear member with respect to the pair of divided housings, and the gear member cannot be easily assembled to the divided housings.

  The present invention provides a gear box mechanism that rotatably supports a gear member between a pair of split housings, and obtains a gear box mechanism that can accurately position and hold the gear member with respect to the split housing. Objective. Another object of the present invention is to provide a gear box mechanism that can easily assemble a gear member to a divided housing.

  According to the present invention, if the bearing bush for rotatably supporting the gear member and the bearing support portion of the pair of split housings are formed in a different shape and the plane portions that engage with each other have a specific structure, the gear member can be accurately attached to the split housing. The present invention has been achieved by paying attention to the fact that it can be positioned and held, and that the gear member can be easily assembled to the divided housing.

  The present invention is a gear box mechanism in which a gear member is rotatably supported between a pair of divided housings, and the gear member has a pair of bearing bushes that are relatively rotatable at both ends in the axial direction. And at least one of the bearing bushes has a non-circular supported portion including a pair of main plane portions parallel to each other and parallel to the dividing direction of the pair of divided housings and sandwiching the axis of the bearing bush. One of the divided housings has a bush support portion having a pair of first main receiving surfaces that are engaged with and supported by the pair of main plane portions of the bearing bush.

  The pair of split housings includes a main housing having the first main receiving surface and a sub-housing having a pair of second main receiving surfaces that are wider than the interval between the pair of main flat surface portions of the bearing bush. Can do.

  The length of at least one of the pair of first main receiving surfaces of the main housing in the sub housing direction may be longer than the length of the pair of second main receiving surfaces of the sub housing in the main housing direction. it can.

  In a preferred embodiment, the non-circular supported portion of the bearing bush has a pair of sub-plane portions that extend in a direction intersecting the extending direction of the pair of main plane portions and sandwich the axis of the bearing bush. The pair of divided housings are each provided with a sub-receiving surface that engages with one and the other of the pair of sub-plane portions of the bearing bush.

  It is desirable that the non-circular supported portion of the bearing bush is formed with a curved surface portion connecting the main plane portion and the sub-plane portion.

  The non-circular supported portion of the bearing bush extends in the axial direction of the gear member, and an axial grease groove in which at least the outer end portion is closed is formed on the inner peripheral surface of both end portions in the axial direction. It is desirable that

  The bearing bush can be formed with an outer flange portion extending radially outward from the non-circular supported portion, and the end portion of the axial grease groove on the outer flange portion side is formed on the end surface of the outer flange portion. It can be opened.

  It is practical to form the axial grease groove in a thick portion formed in the non-circular supported portion.

  In addition, a radial grease groove communicating with the axial grease groove having a radially outer end closed can be formed on the end face of the outer flange portion of the bearing bush.

  In the gear box mechanism of the present invention, between the pair of divided housings, a first gear member having an axis parallel to the dividing direction of the divided housing, and a second gear member meshing with the first gear member, Can be supported. In this aspect, the pair of divided housings may be formed with bearing holes for holding the shaft portion of the first gear member, and the shaft portion of the second gear member may be held by the pair of bearing bushes. it can.

  Specifically, one of the first gear member and the second gear member is a worm gear, and the other is a helical gear.

  According to the present invention, in a gear box mechanism that rotatably supports a gear member between a pair of divided housings, a gear box mechanism that can accurately position and hold the gear member with respect to the divided housing is obtained. be able to. Further, the gear member can be easily assembled to the divided housing.

It is a perspective view of one embodiment of a vehicle seat slide device provided with a gearbox mechanism according to the present invention. It is a disassembled perspective view which shows one Embodiment of the gear box mechanism contained in the vehicle seat slide apparatus of FIG. It is sectional drawing of the division | segmentation housing which follows the III-III line | wire of FIG. 2 in an assembly state. It is sectional drawing of the division | segmentation housing which follows the IV-IV line | wire of FIG. 2 in the same assembly state. FIG. 4 is a cross-sectional view exaggeratingly illustrating a distance between a main receiving surface of a pair of divided housings and a distance between a pair of main plane portions of a bearing bush in the cross-sectional view of the divided housing of FIG. 3. It is sectional drawing which follows the VI-VI line of FIG.

  FIG. 1 shows an example of a seat slide device 10 having a gear box mechanism according to the present invention. The seat slide device 10 includes a lower rail 11 that extends in the vehicle front-rear direction and is fixed to the vehicle floor, and an upper rail 12 that is slidable with respect to the lower rail 11 and is fixed to the lower surface of the seat. A lead screw 13 is fixed to the lower rail 11, and a gear box mechanism 20 having a nut member (gear member, helical gear 22 (FIG. 2)) that is screwed to the lead screw 13 is supported on the upper rail 12.

  Specifically, one end portion (left end portion in FIG. 1) 13a of the lead screw 13 is held by a support bracket 13b fixed in the lower rail 11, and the other end portion (the right end portion) is in the lower rail 11. It is fixed to the support block 13c to be fixed. The rotation of the lead screw 13 is restricted.

  The gear box mechanism 20 is fixed to the upper rail 12 by a fixing bracket 14 that is fixed to a fixing hole 12 b formed in the upper wall 12 a of the upper rail 12. The fixing bracket 14 includes a support wall 14a positioned in parallel with the lead screw 13 between the lead screw 13 and the upper wall 12a of the upper rail 12, and a pair of vertical walls extending in the vertical direction from the front and rear ends of the support wall 14a. 14b and a pair of fixed walls 14c extending in opposite directions along the inner surface of the upper wall 12a from the upper ends of the pair of vertical walls 14b. A fixed hole 14d corresponding to the fixed hole 12b of the upper rail 12 is formed in the pair of fixed walls 14c, and a loose hole 14e (only one in FIG. 1) is formed in the pair of vertical walls 14b. (Shown) is formed. The up-down direction and the left-right direction are based on that of the seat slide device 10 mounted on the vehicle.

  The gear box mechanism 20 is inserted into and supported by a pair of cushioning members (rubber housings) 15 in a U-shaped space defined by the support wall 14a of the fixed bracket 14 and the pair of vertical walls 14b. It is fixed to the upper rail 12 by fixing means (not shown) inserted through the hole 14 d and the fixing hole 12 b of the upper rail 12.

  FIG. 2 is an exploded perspective view of a main part of the gear box mechanism 20. In FIG. 2, the axis of the lead screw 13 is shown as 13O. The gear box mechanism 20 includes a pair of split housings (a left (sub) housing 21L and a right (main) housing 21R). The left (sub) housing 21L and the right (main) housing 21R include vertical abutting reference surfaces P1 and P2 including an axis 13O, and are assembled with the abutting reference surfaces P1 and P2 in contact with each other. (See FIG. 3). The extension of the surface including the abutting reference surfaces P1 and P2 in contact with each other is defined as a center plane X (FIGS. 3 and 4).

  Between the left (sub) housing 21L and the right (main) housing 21R, a helical gear (gear member) (one of a pair of gear members supported between the divided housings 21R and 21L) 22 positioned on the axis 13O; The washer 23 and the synthetic resin bearing bush 24 are respectively housed on both sides of the helical gear 22 in the axial direction. The helical gear 22 has a female screw portion 22a that is screwed to the lead screw 13 at its axis, a helical screw 22b on the outer peripheral surface, and outer cylindrical portions 22c at both ends in the axial direction. The washer 23 has a circular flat plate shape, and an end surface of the helical screw 22b (a boundary surface between the helical screw 22b and the outer cylindrical portion 22c) in a state where the center hole 23a is fitted to the outer cylindrical portion 22c of the helical gear 22. 22d abuts.

  The pair of bearing bushes 24 have the same shape, but in the mounted state, the axial direction is reversed. The bearing bush 24 is a non-circular supported portion supported between the inner cylindrical surface 24a that receives the outer cylindrical portion 22c of the helical gear 22 so as to be relatively rotatable, and the left (sub) housing 21L and the right (main) housing 21R. 24 b and a circular outer flange portion 24 c facing the washer 23. The outer flange portion 24c holds the washer 23 between the end face 22d of the helical screw 22b.

  The non-circular supported portion 24b of the bearing bush 24 includes four plane portions 24bf and four plane portions 24bf each having a square extension surface when viewed from the front (axial direction) and including a plane parallel to the axis of the bearing bush 24. It has a 90 ° rotationally symmetric shape having four curved surface portions 24bc that are smoothly connected (the same shape is obtained by rotating 90 ° about the axis). The extension surfaces of the adjacent flat surface portions 24bf across the curved surface portion 24bc are orthogonal to each other. A chamfering c is provided on the surfaces of the four flat surface portions 24bf and the four curved surface portions 24bc opposite to the outer flange 24c. In the illustrated example, the four curved surface portions 24bc are formed of a part of a cylindrical surface centered on the axis of the inner cylindrical surface 24a, but may be configured from a plane.

  Further, an axial grease groove 24 d extending in a direction parallel to the axis of the bearing bush 24 is formed on the inner peripheral surface of the bearing bush 24 so as to be positioned at the boundary between the flat surface portion 24 bf and the curved surface portion 24 bc. One end of the axial grease groove 24d (the outer end in the axial direction of the helical gear 22) is closed, and the other end is open to the outer flange 24c. Further, as shown in FIG. 6, a radial grease groove 24e communicating with the axial grease groove 24d is formed on the end face of the outer flange portion 24c. The radially outer end of the radial grease groove 24e is closed, and the grease can be held inside the axial grease groove 24d and the radial grease groove 24e. Since the boundary between the flat surface portion 24bf and the curved surface portion 24bc is thick (can be thick), the axial grease groove 24d can be easily formed without reducing the strength of the bearing bush 24. In addition, the axial grease groove 24d can be enlarged to ensure a sufficient amount of grease, and leakage of the grease to the outside can be prevented to prevent grease contamination. Note that the axial grease groove 24d may be configured such that both ends thereof are closed in the non-circular supported portion 24b (inner cylindrical surface 24a).

  The left (sub) housing 21L and the right (main) housing 21R are formed with a semi-cylindrical recess La and a semi-cylindrical recess Ra for receiving the helical gear 22 and the washer 23. The semi-cylindrical recess La and the semi-cylindrical shape are formed. A deformed (non-circular) bush support portion Lb and a deformed (non-circular) bush support portion Rb are formed at both ends in the axial direction of the recess Ra. The boundary between the semicylindrical recess La and the deformed bush support Lb, and the boundary between the semicylindrical recess Ra and the deformed bush support Rb constitute a thrust receiving surface Lc and a thrust receiving surface Rc (see FIG. 3).

  The deformed bush support portion Lb and the deformed bush support portion Rb are an upper receiving surface Lb1 and an upper receiving surface Rb1 corresponding to the flat portion 24bf located above the bearing bush 24, and a lower receiving surface corresponding to the flat portion 24bf located below. Lb2 and lower receiving surface Rb2, left receiving surface Lb3 and right receiving surface Rb3 corresponding to the left and right plane portions 24bf, and cylindrical receiving surface Lb4 and cylindrical receiving surface Rb4 corresponding to curved surface portion 24bc.

  The pair of plane portions 24bf positioned above and below the bearing bush 24 are a pair of main plane portions parallel to each other in the division direction of the left and right divided housings 21L and 21R and parallel to each other across the axis of the bearing bush 24. These are a pair of main plane portions parallel to each other perpendicular to the abutment surfaces P1, P2 (center plane X) of the divided housings 21L, 21R. Moreover, the plane part 24bf located in the right and left of the bearing bush 24 is a sub plane part. The pair of sub-plane portions 24bf sandwiches the axis of the extending bearing bush 24 in a direction intersecting the extending direction of the pair of main plane portions 24bf. The upper receiving surface Lb1 and upper receiving surface Rb1 of the left (sub) housing 21L and the lower receiving surface Lb2 and lower receiving surface Rb2 of the right (main) housing 21R are main receiving surfaces, and the left receiving surface Lb3 and the right receiving surface. The surface Rb3 is a sub-receiving surface.

  Now, the distance (length, nominal dimension) between the pair of flat surface portions 24bf of the bearing bush 24 is x3 (FIGS. 2 and 5), and between the upper receiving surface Rb1 and the lower receiving surface Rb2 of the right (main) housing 21R. The distance (length, nominal dimension) is x1 (FIGS. 3 and 5), and the distance (length, nominal dimension) between the upper receiving surface Lb1 and lower receiving surface Lb2 of the left (sub) housing 21L is x2 (FIG. 3 and FIG. 5), x1 <x3 <x2. FIG. 5 shows this relationship exaggeratedly. The pair of flat surface portions 24bf (distance x3) of the bearing bush 24 are separated from the upper receiving surface Rb1 and the lower receiving surface Rb2 (distance x1) of the right (main) housing 21R. When inserting the bearing bush 24, the bearing bush 24 is elastically deformed by x1-x3 and inserted into the right (main) housing 21R. For this reason, the bearing bush 24 can be held only by one right (main) housing 21R. In other words, the pair of first main receiving surface Rb1, first main receiving surface Rb2 and bearing bush 24 of the right (main) housing 21R have a wrap design. Therefore, the upper receiving surface Rb1 and the lower receiving surface Rb2 of the right (main) housing 21R are referred to as a first main receiving surface Rb1 and a first main receiving surface Rb2, respectively.

  On the other hand, when the other left (sub) housing 21L is put on the right (main) housing 21R holding the bearing bush 24 in this way, the distance x2 between the upper receiving surface Lb1 and the lower receiving surface Lb2 is equal to the bearing bush 24. The distance between the pair of plane portions 24bf is larger than the distance x3 (x2> x3), and a gap is generated between the two, so that the bearing bush 24 can be easily held in the left (sub) housing 21L. In other words, the pair of second main receiving surface Lb1 and second main receiving surface Lb2 of the left (sub) housing 21L and the bearing bush 24 have a clearance design. That is, the bearing bush 24 can be independently held in one of the right (main) housings 21R during the assembly, and the right (main) housing 21R is the main housing and the left (sub) housing 21L is the right (main). It can be used as a sub-housing that overlaps the housing 21R. Therefore, the upper receiving surface Lb1 and the lower receiving surface Lb2 of the left (sub) housing 21L are referred to as a second main receiving surface Rb1 and a second main receiving surface Rb2, respectively.

  In addition, as shown in FIG. 3, the distance (length) y1 from the center surface X of the upper receiving surface Lb1 and the upper receiving surface Rb1, the distance y2 from the center surface X of the left receiving surface Lb3 and the left and right receiving surfaces Rb3, The formation areas of the cylindrical receiving surface Lb4 and the cylindrical receiving surface Rb4 with respect to the central plane X are the same (symmetric), whereas the lower receiving surface Lb2 and the lower receiving surface Rb2 are asymmetrical with respect to the central plane X. The length of the lower receiving surface Rb2 of the (main) housing 21R is longer than the length of the lower receiving surface Lb2 of the left (sub) housing 21L. However, the length of the lower receiving surface Rb2 + Lb2 in FIG. 3 is equal to the length of the upper receiving surface Rb1 + Lb1. Therefore, when the bearing bush 24 is supported between the deformed bush support portion Lb and the deformed bush support portion Rb, the flat portion of the bearing bush 24 is placed on the long lower receiving surface Rb2 (between the upper receiving surface Lb1). 24bf can be supported. The left (sub) housing 21L is formed with a pair of receiving projections Lf positioned below the pair of lower receiving surfaces Rb2 of the right (main) housing 21R.

  A worm gear (the other of a pair of gear members supported between the divided housings 21R and 21L) 25 that meshes with the helical screw 22b of the helical gear 22 is supported between the left (sub) housing 21L and the right (main) housing 21R. The The worm gear 25 includes a worm 25a meshing with the helical screw 22b, an outer cylindrical portion 25b positioned at both ends in the axial direction of the worm 25a, and a hexagonal cross section (non-circular cross section) positioned between the worm 25a and the outer cylindrical portion 25b. Part) 25c. The hexagonal cross section 25c is fitted with a resin washer 26 having a hexagonal hole 26a corresponding to the hexagonal cross section 25c. The left (sub) housing 21L and the right (main) housing 21R have bearing holes Le and bearings in which worm recesses Ld and worm recesses Rd for receiving both ends of the worm gear 25 and outer cylindrical portions 25b are rotatably fitted. A hole Re is formed (see FIG. 4).

  An insertion hole Lg (FIGS. 2 and 3) for the fixing bolt 27 is formed on the left (sub) housing 21L side, and the female screw hole Rg (in which the fixing bolt 27 is screwed into the right (main) housing 21R). The same) is formed.

  The above gear box mechanism 20 is assembled as follows, for example. In a state in which the left (sub) housing 21L and the right (main) housing 21R are disassembled, the washer 23 and the inner cylindrical surface 24a of the bearing bush 24 are fitted into the outer cylindrical portions 22c at both ends of the helical screw 22b of the helical gear 22. Further, the worm 25a of the worm gear 25 is temporarily meshed with the helical screw 22b. In this temporarily assembled state, the pair of bearing bushes 24 are fitted into the deformed bush support portion Rb of the right (main) housing 21R. That is, a pair of upper and lower plane portions (main plane portions) 24bf are fitted between the upper receiving surface (first main receiving surface) Rb1 and the lower receiving surface (first main receiving surface) Rb2. At this time, the distance x3 between the pair of flat surface portions 24bf of the bearing bush 24 is larger than the distance x1 between the upper receiving surface Rb1 and the lower receiving surface Rb2 of the right (main) housing 21R, so that the bearing bush 24 has a distance x1-x3. It is compressed and deformed by the amount and inserted into the right (main) housing 21R. For this reason, the bearing bush 24 can be held by only one right (main) housing 21R even in a situation where the left (sub) housing 21L is not mounted on the right (main) housing 21R, and the axial shift of the helical gear 22 occurs. Absent. Four curved surface portions (chamfered portions) 24bc (and chamfered portions c) positioned between the four flat surface portions 24bf of the bearing bush 24 facilitate the insertion of the bearing bush 24 into the housings 21R and 21L.

  Further, since the lower receiving surface Rb2 of the right (main) housing 21R is longer than the lower receiving surface Lb2 of the left (sub) housing 21L, the bearing bush 24 (helical gear 22) can be mounted only by the right (main) housing 21R. Helps support. On the other hand, the distance x2 between the upper receiving surface Lb1 and the lower receiving surface Lb2 of the left (sub) housing 21L is larger than the distance x3 of the pair of flat surface portions 24bf of the bearing bush 24, and is thus held by the right (main) housing 21R. The right (main) housing 21R can be covered with the left (sub) housing 21L (function as a lid) with minimum interference with the bearing bush 24.

  In parallel with the above preparation on the helical gear 22 side, the resin washer 26 is fitted to the hexagonal cross section 25c at both ends of the worm gear 25 in which the worm 25a is temporarily meshed with the helical screw 22b of the helical gear 22, and one outer cylindrical portion 25b is attached. Fit into the bearing hole Re of the right (main) housing 21R. Thus, by fitting the pair of upper and lower flat portions 24bf of the bearing bush 24 into the upper receiving surface Rb1 and the lower receiving surface Rb2 of the right (main) housing 21R, and further fitting the worm gear 25 into the bearing hole Re of the main housing 21R. The shafts of the worm gear 25 and the helical gear 22 can be held by the right (main) housing 21R. That is, the shafts of the meshed worm gear 25 and the helical gear 22 can be correctly held by only one housing 21R.

  Next, in the state where the helical gear 22 and the worm gear 25 are assembled (supported) on the right (main) housing 21R side in this way, the left (sub) housing 21L is combined with the right (main) housing 21R, and the left (sub) The bearing bush 24 is fitted into the deformed bush support Lb of the housing 21L. That is, the upper and lower plane portions 24bf of the bearing bush 24 are fitted to the upper receiving surface Lb1 and the lower receiving surface Lb2 of the left (sub) housing 21L. At the same time, the other outer cylindrical portion 25b of the worm gear 25 is fitted into the bearing hole Le of the left (sub) housing 21L.

  With the left and right housings 21L and 21R overlapped as described above, the fixing bolt 27 inserted from the insertion hole Lg of the left (sub) housing 21L is screwed into the female screw hole Rg (same) of the right (main) housing 21R. The left (sub) housing 21L and the right (main) housing 21R are fixed. In this assembled state, the flat portions 24bf positioned above and below the bearing bush 24 are provided with the upper and lower receiving surfaces Rb1 and Rb2 of the right (main) housing 21R and the upper and lower receiving surfaces Lb1 and Lb1 of the left (sub) housing 21L. The vertical position of the bearing bush 24 (helical gear 22) is determined by engaging with the receiving surface Lb2, and the planar portion 24bf positioned on the left and right sides of the left receiving surface Lb3 of the left (sub) housing 21L and the right (main) housing 21R. The position of the bearing bush 24 (helical gear 22) in the left-right direction is determined by engaging with the right receiving surface Rb3. As a result, smooth rotation of the helical gear 22 can be ensured. Further, since the worm gear 25 is held in the bearing hole Re of the right (main) housing 21R and the bearing hole Le of the left (sub) housing 21L, the helical gear 22 and the worm gear 25 are correctly meshed, and smooth rotation transmission and abnormal noise are achieved. Can be prevented.

  Further, in the assembled state of the gear box mechanism 20, the washer 23 on the helical gear 22 side is sandwiched between the end face 22d of the helical gear 22 and the outer flange portion 24c of the bearing bush 24, and the resin washer 26 on the worm gear 25 side is The worm 25a is sandwiched between both end faces of the worm recess Ld and the inner wall of the worm recess Rd to restrict axial movement. The washer 23 is in contact with and engaged with the thrust receiving surface Lc and the thrust receiving surface Rc.

  Before the gear box mechanism 20 is fixed to the upper wall 12 a of the upper rail 12 via the fixing bracket 14, the lead screw 13 is screwed into the female screw portion 22 a of the helical gear 22. The lead screw 13 is then fixed to the lower rail 11 in a state where rotation is constrained, and the fixing bracket 14 is fixed to the upper rail 12 to form the seat slide device 10. When the worm gear 25 is driven to rotate forward and backward by an electric drive mechanism (not shown), the axial movement of the helical gear 22 causes the thrust receiving surface Lc of the left (sub) housing 21L and the thrust receiving surface Rc of the right (main) housing 21R. The helical gear 22 (gearbox mechanism 20), which is regulated by the (a pair of bearing bushes 24) and screwed through the lead screw 13 and the female screw portion 22a, that is, the upper rail 12 moves back and forth along the lower rail 11. .

  In the above embodiment, the left (sub) housing 21L and the right (main) housing 21R are asymmetrical, and the long lower receiving surface (first main receiving surface) Rb2 and upper receiving surface (first) of the right (main) housing 21R. There is an advantage that the bearing bush 24 can be more stably held by the long lower receiving surface Rb2 between the first main receiving surface) Rb1. However, the lengths of the lower receiving surface (first main receiving surface) Rb2 and the lower receiving surface (second main receiving surface) Lb2 may be the same.

  On the other hand, in the illustrated embodiment, the left and right housings 21L and 21R have an interval between the upper receiving surface Rb1 and the lower receiving surface Rb2 (interval of the first main receiving surface) and an interval between the upper receiving surface Lb1 and the lower receiving surface Lb2 (first). 2), except for the length of the lower receiving surface Rb2 and the presence of the receiving projection Lf, the shape is symmetrical with respect to the center plane X, but other portions can also be asymmetrical. Specifically, in FIG. 3, the abutting reference planes P1 and P2 may be shifted leftward so that the lengths of the upper receiving surface Lb1 and the upper receiving surface Rb1 are different.

  Further, the bearing bush 24 has four planar portions 24bf having a square front shape (90 ° rotationally symmetric shape), but may have a polygonal shape such as an octagonal shape or a dodecagonal shape having planar portions on the top and bottom and the left and right. . A particularly important surface is a pair of upper and lower plane portions 24bf, and the surface shape connecting the upper and lower plane portions 24bf has a degree of freedom. For example, it may be composed of only a part of a cylindrical surface, or may have a polygonal shape, or a 180 ° rotationally symmetric shape.

  In the above embodiment, the worm gear is supported as a first gear member having an axis parallel to the dividing direction of the split housing between the pair of split housings 21R and 21L, and the second gear meshing with the first gear member is engaged. The pair of divided housings are formed with bearing holes for holding the shaft portions of the worm gears, and the shaft portions of the helical gears are held by the pair of bearing bushes. Yes. However, a mode in which the shaft portion of the worm gear is supported by the pair of bearing bushes and the shaft portion of the helical gear is held in a bearing hole formed in the pair of split housings is also possible.

  In the above embodiment, the present invention is applied to a gear box mechanism that rotatably supports a helical gear 22 that is screwed into a lead screw 13 that is constrained to rotate. The present invention can also be applied to an integral gear box mechanism (that is, a gear box mechanism that rotationally drives the lead screw 13). Moreover, the mechanism which transmits rotation to the helical gear 22 is not ask | required.

DESCRIPTION OF SYMBOLS 10 Seat slide apparatus 11 Lower rail 12 Upper rail 12a Upper wall 12b Fixing hole 13 Lead screw 13a One end part 13b Support bracket 13c Support block 13O Axis 14 Fixing bracket 14a Support wall 14b Vertical wall 14c Fixing wall 14d Fixing hole 14e Relaxing hole 15 Buffering member 20 Gearbox mechanism 21L Left housing (split housing, sub-housing)
21R Right housing (split housing, main housing)
22 Helical gear (gear member)
22a Female thread portion 22b Helical screw 22c Outer cylindrical portion 22d End surface 23 Washer 23a Center hole 24 Bearing bush 24a Inner cylindrical surface 24b Non-circular supported portion 24bf Flat portion 24bc Curved portion 24c Outer flange portion 24d Axial grease groove 24e Radial grease groove 25 Worm gear 25a Worm 25b Outer cylindrical portion 25c Hexagonal cross section 26 Resin washer 26a Hexagonal hole 27 Fixing bolt La Ra Semi-cylindrical recess Lb Rb Deformed bush support (bush support)
Rb1 Top bearing surface (first main bearing surface)
Rb2 under surface (first main surface)
Lb1 Top bearing surface (second main bearing surface)
Lb2 under surface (second main surface)
Lb3 Left receiving surface (sub-receiving surface)
Rb3 Right receiving surface (sub-receiving surface)
Lb4 Rb4 Cylindrical receiving surface Lc Rc Thrust receiving surface Ld Rd Worm recess Le Re Bearing hole Lf Receiving protrusion Lg Inserting hole Rg Female thread hole P1 P2 Abutting reference surface X Center surface

Claims (11)

A gear box mechanism that rotatably supports a gear member between a pair of divided housings,
The gear member has a pair of bearing bushes that are relatively rotatable at both ends in the axial direction;
At least one of the bearing bushes has a non-circular supported portion having a pair of main plane portions parallel to each other in parallel to the dividing direction of the pair of divided housings and sandwiching the axis of the bearing bush; One of the divided housings has a bush support portion having a pair of first main receiving surfaces that engage and support the pair of main plane portions of the bearing bush;
Gear box mechanism characterized by 2. The gear box mechanism according to claim 1, wherein the pair of divided housings are a pair of second main supports having a larger interval than a distance between the main housing having the first main receiving surface and the pair of main plane portions of the bearing bush. A gear box mechanism comprising a sub-housing having a surface. The gear box mechanism according to claim 2,
A gear box mechanism in which at least one of the pair of first main receiving surfaces of the main housing is longer than the pair of second main receiving surfaces of the sub housing in the main housing direction. . The gear box mechanism according to any one of claims 1 to 3, wherein the non-circular supported portion of the bearing bush extends in a direction intersecting with an extending direction of the pair of main plane portions. A gearbox mechanism having a pair of sub-plane portions sandwiching the axis of the bush, and the pair of divided housings each having a sub-receiving surface that engages one and the other of the pair of sub-plane portions of the bearing bush. 5. The gear box mechanism according to claim 4, wherein the non-circular supported portion of the bearing bush is formed with a curved surface portion connecting the main plane portion and the sub-plane portion. 6. The gear box mechanism according to claim 1, wherein the non-circular supported portion of the bearing bush extends in the axial direction of the gear member, and at least an outer end of both end portions in the axial direction on the inner peripheral surface thereof. A gear box mechanism in which an axial grease groove with a closed portion is formed. 7. The gearbox mechanism according to claim 6, wherein the bearing bush has an outer flange portion extending radially outward from the non-circular supported portion, and an end portion of the axial grease groove on the outer flange portion side is A gearbox mechanism that opens to the end face of the outer flange. The gear box mechanism according to claim 7, wherein the axial grease groove is formed in a thick part formed in the non-circular supported part. 9. The gear box mechanism according to claim 7 or 8, wherein a radial grease groove communicating with the axial grease groove and having a radially outer end closed is formed on an end face of the outer flange portion. Gear box mechanism. 2. The gear box mechanism according to claim 1, wherein the gear member includes a first gear member having an axis parallel to a split direction of the pair of split housings, and a second gear member meshing with the first gear member. The pair of divided housings are formed with bearing holes for holding the shaft portion of the first gear member, and the shaft portion of the second gear member is held by the pair of bearing bushes. Gear box mechanism. 11. The gear box mechanism according to claim 10, wherein one of the first gear member and the second gear member is a worm gear and the other is a helical gear.

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