JP2014098437A - Bolt fastening structure for vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bolt fastening structure for a vehicle that can make compatible a high antitheft effect and sufficient workability at vehicle maintenance or the like.SOLUTION: Since a turning angle of a loosening tool 50 is limited when loosening a fastening bolt 16 by using a loosening tool 50, a high antitheft effect for preventing a bracket 12 from being illegally removed from a transmission case 14 is secured. Since work for loosening the fastening bolt 16 is progressed by making the loosening tool 50 engaged with a polygonal part 22, the sufficient workability at the vehicle maintenance or the like is also secured. The whirl stop of a protector member 38 with respect to the bracket 12 is achieved by inserting a leg 32b of a washer 32 into an insertion hole 47a of the protecting member 38 and an insertion hole 47b of the bracket 12, there is no necessity for welding the protector member 38 to the bracket 12, and manufacturing costs can be reduced.

Description

  The present invention relates to a structure for fastening a plurality of members to each other with bolts in a vehicle.

  2. Description of the Related Art Conventionally, a bolt fastening structure for a vehicle in which a fastening member is fixed to a fastened member with a bolt is well known. For example, this is the fastening structure disclosed in Patent Document 1. Patent Document 1 discloses a fastening structure in which, for example, an SBW motor is externally attached to a transmission case. In the fastening structure of Patent Document 1, the fastening member surrounds the bolt and the head of the bolt and has an open end. It fixes to the said to-be-fastened member with the fastener provided with the bottomed cylindrical protector which has. Then, after the fastening of the fastening member to the fastened member is completed, a cap member that closes the open end of the protector is fitted into the protector. As a result, since it becomes impossible to loosen the bolt by directly engaging the tool with the bolt, it takes a long time to remove the SBW motor from the transmission case. Therefore, it is possible to prevent the vehicle theft executed by removing the SBW motor and unlocking the drive wheels.

JP 2009-109003 A JP 2008-22001 A

  According to the fastening structure of Patent Document 1, it is possible to obtain a high antitheft effect that prevents the fastening member from being unfairly removed from the fastened member. However, it may be necessary to remove the fastening member from the fastened member during vehicle maintenance, etc., and in this case, good workability is required, but it takes time to loosen the bolt. There was a problem that workability was bad. When an operation including loosening the bolt in a state where the device including the fastened member and the fastening member is mounted on a vehicle, it is considered that workability is further deteriorated due to a limitation of a working space or the like. Such a problem is not yet known.

  The present invention has been made against the background of the above circumstances, and its object is to provide a bolt fastening structure for a vehicle that can achieve both a high antitheft effect and sufficient workability during vehicle maintenance. There is to do.

  The subject matter of the first invention for achieving the above object is (a) a bolt fastening structure for a vehicle in which a fastening member is fixed to a fastened member with a fastening bolt, and (b) the fastening bolt. Are a screw part screwed into a screw hole of the fastened member, a polygonal part having a polygonal cross section perpendicular to the axis of the fastening bolt, and an axial direction of the screw part across the polygonal part A tightening tool engaging portion that is provided on the opposite side and that engages a tightening tool that rotates the tightening bolt in the tightening direction from the axial direction; and (c) the bolt fastening structure includes the fastening A bolt hole through which a threaded portion of the bolt is inserted is formed in the bottom portion, accommodates the polygonal portion of the fastening bolt and opens on the opposite side in the axial direction with respect to the bottom portion, and the bottom portion of the protector member and the fastening member Inserted between the bolt and the front A washer having a leg protruding from the bottom side and the fastening tool engaged with the fastening tool engaging portion prevent the fastening bolt from rotating in a loosening direction from the fastened state. (D) the protector member is formed on a side, the loosening tool engaged with the polygonal portion is inserted, and the loosening tool loosens the fastening bolt. (E) the fastening member is a screw of the fastening bolt; and (e) the fastening member is a screw of the fastening bolt, and includes an opening allowing rotation with the fastening bolt, and an insertion portion formed at the bottom and through which the leg portion of the washer is inserted. A bolt hole through which the portion is inserted, and a locking portion that receives the leg portion of the washer and prevents the leg portion from rotating about the axis of the fastening bolt. To do.

  In this way, in the state in which the fastening bolt is fastened, the fastening bolt cannot be loosened by the fastening tool from the axial direction of the fastening bolt, and the fastening bolt can be fastened by the loosening tool. When loosening the bolt, since the rotation angle of the loosening tool is limited by the opening width of the opening, it is assumed that the fastening bolt is loosened with the tightening tool on the assumption that there is no loosening prevention device; In comparison, it is difficult to loosen the fastening bolt. Therefore, it is possible to ensure a high anti-theft effect that prevents the fastening member from being unduly removed from the fastened member. When the loosening tool is engaged with the polygonal part, the work of loosening the fastening bolt can be reliably advanced, and the fastening bolt is rotated in the loosening direction as the work progresses. Therefore, it is possible to ensure sufficient workability during vehicle maintenance and the like. A washer inserted between the bottom portion of the protector member and the fastening bolt has a leg portion, and the leg portion is inserted into an insertion portion formed in the bottom portion of the protector member and formed in the fastening member. It is possible to achieve the detent of the protector member with respect to the fastening member by being received by the engaging portion, and it is not necessary to weld the protector member to the fastening member, thereby reducing the manufacturing cost. it can.

  Here, the gist of the second invention is the bolt fastening structure for a vehicle according to the first invention, wherein (a) the fastening tool engaging portion is opened in an axial direction, and the fastening tool is And a bottom screw hole provided on a bottom surface of the polygon hole, and (b) the loosening operation blocking device is configured such that the bottom screw hole is in a state in which the fastening bolt is fastened. It consists of the residual part of the shear bolt sheared in the state screwed together. In this way, the tightening tool cannot be easily and reliably engaged with the tightening tool engaging portion by the remaining portion of the shear bolt, and the tightening bolt cannot be loosened by the tightening tool. It is possible.

  The gist of the third invention is the bolt fastening structure for a vehicle according to the first invention or the second invention, wherein (a) the polygonal shape in a cross section perpendicular to the axis of the polygonal part is an even angle. (B) the opening width in the circumferential direction of the axial center of the fastening bolt of the opening portion is a plurality of pairs of parallel surfaces constituting the outer peripheral side surface of the polygonal portion of the fastening bolt. While allowing the loosening tool to rotate the fastening bolt at a rotation angle equal to or greater than a unit rotation angle at which the pair of parallel surfaces rotate to the position of the other adjacent parallel surface, It is an opening width which prevents rotation of the loosening tool that rotates the fastening bolt at a rotation angle that is twice or more the unit rotation angle. In this way, the tightening bolt can be reliably loosened by the loosening tool engaged with the polygonal part, and the high theft can be achieved by limiting the rotation angle of the loosening tool by the opening. It is possible to ensure the prevention effect.

  A gist of a fourth invention is the bolt fastening structure for a vehicle according to any one of the first invention to the third invention, wherein one of a plurality of bolt fastening locations including a fastening location by the fastening bolt. The protector member is provided only in the portion. In this way, while securing the high antitheft effect by the fastening bolt and the protector member, at the place where the protector member is not provided among the plurality of bolt fastening places, the fastening member is When removing from the fastened member, high workability of loosening the bolt can be ensured.

  The gist of the fifth invention is the bolt fastening structure for a vehicle according to any one of the first invention to the fourth invention, wherein the outer diameter of the fastening tool engaging portion is that of the polygonal portion. It is larger than the dimension between a pair of parallel surfaces. If it does in this way, the said clamping tool engaging part will prevent that the tool inserted from the opening hole opened to the axial direction of the said protector member engages with the said polygon part by the external shape. As a result, since the tool cannot be engaged with the polygonal part from the axial direction of the fastening bolt, the outer diameter of the fastening tool engaging part is smaller than the dimension between the pair of parallel surfaces of the polygonal part. Compared to the case, it is possible to ensure a high antitheft effect.

  Here, preferably, among the plurality of bolt fastening portions, the protector member is fastened by the fastening bolt at a place where the protector member is provided on the fastening member, while the protector member is attached to the fastening member. In the place which is not provided, it is fastened with a standard bolt in accordance with a predetermined public standard.

  Preferably, the tightening tool is a tool according to a predetermined public standard. The loosening tool is also a tool according to a predetermined public standard.

FIG. 2 is a diagram showing a bolt fastening structure for a vehicle according to the present invention, and shows a state in which an SBW motor that is an actuator for performing shift-by-wire control (SBW control) is bolted to a transmission case of a vehicle via a bracket. FIG. It is the bottom view which looked at the SBW motor, the bracket, and the transmission case from the lower side in FIG. It is sectional drawing of the bolt fastening location which fixes the bracket of FIG. 1 to a transmission case, specifically, AA arrow sectional drawing in FIG. It is the front view which showed the bracket and protector member of FIG. 1 in the same direction as FIG. It is the bottom view which looked at the bracket and protector member in the arrow AR02 direction from the downward direction in FIG. It is the side view which looked at the bracket and protector member in the arrow AR03 direction in FIG. It is the front view which showed the bracket alone in the same direction as FIG. It is the front view which showed the volt | bolt for fastening and the protector member in the same direction as FIG. It is DD sectional view taken on the line in FIG. FIG. 4 is a perspective view showing a fastening bolt shown in FIG. 3 alone. It is sectional drawing of the polygonal part of the fastening volt | bolt of FIG. 3, ie, BB arrow sectional drawing in FIG. It is a figure showing the state where the loosening tool is engaged with the fastening bolt of FIG. 1, wherein the protector member of the bracket is represented by a cross section perpendicular to the bolt axis (CC cross section in FIG. 3). It is a figure. It is the front view which showed another bracket replaced with the bracket of FIG. It is the front view which showed another protector member replaced with the protector member of FIG. It is the side view which looked at the protector member in arrow AR04 direction in FIG. It is the figure which showed the 1st example of another fastening bolt replaced with the fastening bolt of FIG. It is the figure which showed the 2nd example of another fastening bolt replaced with the fastening bolt of FIG. It is the figure which showed the 3rd example of another fastening bolt replaced with the fastening bolt of FIG. It is the figure which showed the 4th example of another fastening bolt replaced with the fastening bolt of FIG. It is the figure which showed the 5th example of another fastening bolt replaced with the fastening bolt of FIG. It is the figure which showed the 6th example of another fastening bolt replaced with the fastening bolt of FIG.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a view showing a bolt fastening structure 8 for a vehicle according to the present invention, in which a SBW motor 10 which is an actuator for performing shift-by-wire control (SBW control) is connected to a vehicle transmission case via a bracket 12. FIG. 14 is a front view showing a state in which the bolt is fastened to 14. FIG. 2 is a bottom view of the SBW motor 10, the bracket 12, and the transmission case 14 as viewed in the direction of the arrow AR01 from below in FIG. FIG. 3 is a cross-sectional view of a bolt fastening portion that fixes the bracket 12 to the transmission case 14, specifically, a cross-sectional view taken along line AA in FIG. 1. 4 is a front view showing the bracket 12 and the protector member 38 in the same direction as FIG. FIG. 5 is a bottom view of the bracket 12 and the protector member 38 in FIG. 4 viewed from below in the direction of the arrow AR02. FIG. 6 is a side view of the bracket 12 and the protector member 38 as viewed in the direction of the arrow AR03 in FIG. FIG. 7 is a front view showing the bracket 12 alone in the same direction as FIG. FIG. 8 is a front view showing the fastening bolt 16 and the protector member 38 in the same direction as FIG. 9 is a cross-sectional view taken along the line DD in FIG. FIG. 10 is a perspective view showing the fastening bolt 16 shown in FIG. 3 as a single unit. 11 is a cross-sectional view of the polygonal portion 22 of the fastening bolt 16, that is, a cross-sectional view taken along the line BB in FIG. The SBW motor 10 and the bracket 12 correspond to the fastening member in the present invention, and the transmission case 14 corresponds to the fastened member in the present invention.

  The SBW motor 10 is an electric motor that is provided in the transmission case 14 and operates a known parking lock mechanism that locks drive wheels. That is, by the rotation operation of the SBW motor 10, the parking lock mechanism is selectively switched between a locked state in which the driving wheel is locked and an unlocked state in which the driving wheel is allowed to rotate. Therefore, for example, when the SBW motor 10 is removed from the transmission case 14 when the parking lock mechanism is in the locked state, the locked state of the parking lock mechanism can be released regardless of the shift operation.

  The SBW motor 10 is fixed to the bracket 12 by bolting or the like, and cannot be removed from the bracket 12 when the bracket 12 is attached to the transmission case 14. For example, in the SBW motor 10, the motor connecting bolt inserted from the transmission case 14 side into the bolt hole 37 provided in the bracket body 36 is screwed into the screw hole formed in the SBW motor 10, so that the bracket 12 The motor connection bolt is fixed so that the transmission case 14 prevents the tool from being engaged with the motor connection bolt when the bracket 12 is attached to the transmission case 14. .

  The transmission case 14 is a non-rotating member made of metal and is a housing of a vehicle transmission. The transmission case 14 includes three screw holes 15 in which female screws to which bolts (fastening bolts 16 and hexagon bolts 18) to which the bracket 12 is attached are formed.

  The bracket 12 includes bolt shafts RCb1 and RCb2 parallel to the motor shaft RCm at a plurality of locations around the shaft center RCm (hereinafter referred to as motor shaft RCm) of the SBW motor 10, specifically at three locations. , Fixed to the transmission case 14 by bolting in the RCb3 direction. Specifically, the bracket 12 is fastened to the transmission case 14 by fastening bolts 16 at two locations on the bolt shaft centers RCb1 and RCb2, and a predetermined public standard (on the remaining bolt shaft centers RCb3) The bracket 12 is fastened to the transmission case 14 by standard bolts according to JIS standards, ISO standards, etc., for example, hexagon bolts 18 (JIS B 1180) according to JIS standards. When the bolt shaft centers RCb1, RCb2, and RCb3 are not particularly distinguished, they are represented as bolt shaft centers RCb.

  Since both the bolt shaft centers RCb1 and RCb2 use the same fastening bolt 16, the fastening bolt 16 on the bolt shaft center RCb1 will be described as an example. The fastening bolt 16 includes a screw part 20, a polygonal part 22, and a fastening tool engaging part 24 in series on the bolt axis RCb1 in order from the bolt tip. The screw portion 20, the polygonal portion 22, and the tightening tool engaging portion 24 are all integrally formed with the bolt axis RCb1 as the central axis. The screw portion 20 is formed of a male screw that is screwed into a screw hole (female screw) 15 formed in the transmission case 14. The screw portion 20 is coated with a locking agent which is a kind of adhesive for making it difficult to loosen the fastening bolt 16 screwed into the screw hole 15 of the transmission case 14.

  The polygonal portion 22 has a polygonal shape in which the cross section perpendicular to the bolt axis RCb1 has an even number of angles, specifically, a regular polygonal shape that forms a regular octagon. That is, the polygonal part 22 has an even polygonal regular polygonal column shape with the bolt axis RCb1 as the central axis. A dimension between a pair of parallel surfaces constituting the outer peripheral side surface of the polygonal portion 22, that is, a dimension of a two-surface width, for example, a two-surface width dimension GPs shown in FIGS. The dimensions conform to JIS B 1002).

  The tightening tool engaging portion 24 has a cylindrical shape with the bolt shaft center RCb1 as the central axis, and is provided on the opposite side of the screw portion 20 in the axial direction with the polygonal portion 22 in between. The outer diameter (diameter) of the tightening tool engaging portion 24 is larger than the dimension between the pair of parallel surfaces of the polygonal portion 22 (= two-surface width dimension GPs). The tightening tool engaging portion 24 is formed with a polygonal hole 26 opened in the direction of the bolt axis RCb1 at the end of the axial direction tip, and in the polygonal hole 26 on the bolt axis RCb1, A fastening tool 27 (see FIG. 3) for rotating the fastening bolt 16 in the fastening direction is engaged from the direction of the bolt axis RCb1 (upper side in FIG. 3). For example, the polygonal hole 26 may be a polygonal shape such as a quadrangular shape, a pentagonal shape, or an octagonal shape, but in this embodiment, a hexagonal hole conforming to a predetermined public standard (for example, JIS B 1002). It is. Since such a tightening tool engaging portion 24 is provided, in the operation of fixing the bracket 12 to the transmission case 14 with the fastening bolt 16, the tightening tool 27 is a polygon of the tightening tool engaging portion 24. The fastening bolt 16 is fitted into the hole 26 from the direction of the bolt axis RCb1 and the fastening tool 27 fitted into the polygonal hole 26 is continuously rotated in the fastening direction of the fastening bolt 16. Tightened. The tightening tool 27 may be a special tool, but is, for example, a hexagonal wrench according to a predetermined public standard (for example, JIS B 4648). The bottom surface 28 of the polygonal hole 26 is provided with a bottom screw hole 30 which is a stop hole formed including a female screw having the bolt shaft center RCb1 as a central axis.

  The fastening bolt 16 includes a washer (washer) 32 in addition to the bolt main body including the screw portion 20, the polygonal portion 22, and the fastening tool engaging portion 24. In other words, the washer 32 is attached to the fastening bolt 16 when the bracket 12 and the protector member 38 are assembled. The washer 32 is a thin plate member made of, for example, a metal material, and is provided in an L shape from the thin disk-shaped disk-shaped portion 32a whose outer diameter is larger than the polygonal portion 22 and the outer peripheral portion of the disk-shaped portion 32a. This is an L-shaped washer provided with a leg portion (projection portion) 32b. That is, as the leg portion 32b, a first projecting portion projecting radially outward from the outer peripheral portion of the disk-shaped portion 32a and a first projecting portion projecting in the axial direction from the outer peripheral end of the first projecting portion. 2 protrusions. The disc-shaped portion 32 a has an insertion hole 32 c through which the proximal end of the screw portion 20 is inserted at the center thereof, and does not fall off between the portion where the male screw of the screw portion 20 is formed and the polygonal portion 22. The bolt body is gently locked to the extent. The washer 32 is attached to the fastening bolt 16 so that the second protruding portion of the leg portion 32b protrudes toward the screw portion 20 side. As shown in FIG. 10 and the like, in the present embodiment, the second projecting portion of the leg portion 32b of the washer 32 is formed in a partial cylindrical shape centering on the axis of the disc-like portion 32a, that is, its width direction. Although it is curved in a direction perpendicular to the axial direction, it may be configured in a flat plate shape having no curvature in the width direction. In such an embodiment, an insertion hole 47a formed in the cover bottom 40, which will be described later, and 47b formed in the bracket 12 are configured, for example, in a straight line (longitudinal rectangular shape) according to the shape of the leg 32b of the washer 32. .

  The bracket 12 is a connecting member interposed between the SBW motor 10 and the transmission case 14 in order to fix the SBW motor 10 to the transmission case 14. In the bolt fastening structure 8 of the present embodiment, a plurality of protector members 38 are fastened by fastening bolts 16 at corresponding bolt shaft centers RCb1 and RCb2 with respect to a bracket body 36 made of a sheet metal part formed by pressing. Has been configured.

  The protector member (bolt cover member) 38 is provided at a part of the three bolt fastening locations where the bracket 12 is fastened to the transmission case 14. Specifically, the protector member 38 is provided at two locations on the bolt shaft centers RCb1 and RCb2 where the bracket 12 is fastened to the transmission case 14 by the fastening bolts 16, while the bracket 12 is fastened by the hexagon bolts 18. Is not provided on the bolt shaft center RCb3 fastened to the transmission case 14. The protector member 38 is fastened by fastening bolts 16 to surfaces 39a and 39b opposite to the transmission case 14 side of the bracket body 36 at two locations on the bolt shaft centers RCb1 and RCb2.

  Since both the bolt shaft centers RCb1 and RCb2 use the same protector member 38, the protector member 38 will be described by taking the protector member 38 on the bolt shaft center RCb1 as an example. The protector member 38 is a bottomed cylindrical member composed of a cover bottom portion 40, a bolt housing portion 42, and an opening 44. The cover bottom portion 40 has a plate shape whose thickness direction is in the direction of the bolt axis RCb1, and a through hole 46a centering on the bolt axis RCb1 is formed. As shown in FIG. 3, the through hole 46 a of the cover bottom portion 40 is a bolt hole of the bracket 12 through which the screw portion 20 of the fastening bolt 16 is inserted together with the through hole 46 b of the bracket body 36 formed coaxially therewith. 46 is constituted. In this embodiment, the protector member 38 is the same member for both of the bolt shaft centers RCb1 and RCb2, but the two protector members 38 provided on the bolt shaft centers RCb1 and RCb2 may not be the same member. It is not necessary to have the same shape as each other.

  The cover bottom 40 of the protector member 38 is provided with an insertion hole 47a as an insertion portion through which the leg portion 32b (second protrusion) of the washer 32 is inserted in the thickness direction. The insertion hole 47a is preferably configured to receive the leg portion 32b of the washer 32 and prevent the leg portion 32b from rotating about the bolt axis RCb1. Specifically, the sidewalls at both ends in the longitudinal direction of the insertion hole 47a function as a configuration that prevents the leg portion 32b of the washer 32 from rotating around the bolt axis RCb1. The bracket body 36 receives the leg portion 32b of the washer 32 at a position coincident with the insertion hole 47a formed in the cover bottom portion 40 in a state where the protector member 38 is provided at a correct position with respect to the bracket body 36. An insertion hole 47b is formed as a locking portion that prevents the leg 32b from rotating around the axis of the fastening bolt 16. Specifically, the side walls at both ends in the longitudinal direction of the insertion hole 47b function as a configuration that prevents the leg portion 32b of the washer 32 from rotating around the bolt axis RCb1. In the present embodiment, the insertion hole 47a of the cover bottom 40 and the insertion hole 47b of the bracket body 36 are both circular with the bolt shaft center RCb1 as the center in accordance with the shape of the second protrusion of the leg 32b of the washer 32. It is formed in an arc shape, that is, in a shape curved in the longitudinal direction (direction perpendicular to the axial direction). The insertion hole 47a in the cover bottom portion 40 and the insertion hole 47b in the bracket body 36 are preferably formed in substantially the same shape in plan view (when viewed in the direction of the bolt axis RCb1).

  In the state where the fastening bolt 16, the protector member 38 and the bracket 12 are assembled to each other, the insertion hole 47a of the cover bottom 40 is formed on the same axis as the bracket body as shown in FIGS. The leg 32b in the washer 32 of the fastening bolt 16 is received together with the 36 insertion holes 47b. In other words, the leg portion 32 b of the washer 32 of the fastening bolt 16 is inserted into the insertion hole 47 a of the cover bottom 40 and the insertion hole 47 b of the bracket body 36. With such a configuration, the fastening bolt 16, the protector member 38, and the bracket 12 are assembled to each other. As a result, the bracket 12 and the protector member 38 are attached to the transmission case 14 and fastened on the bolt axis RCb 1. When the fastening bolt 16 is completely fastened, the protector member 38 is prevented from rotating with respect to the bracket 12 by the leg 32b of the washer 32 inserted through the insertion hole 47a of the cover bottom 40 and the insertion hole 47b of the bracket body 36, that is, a bolt shaft. Suppression of relative rotation around the center RCb1 can be realized. That is, in this embodiment, it is not necessary to weld the protector member 38 to the bracket 12 (bracket body 36), and the manufacturing cost can be reduced.

  In the bolt housing portion 42, the bracket main body 36 side is closed by the cover bottom portion 40 in the direction of the bolt axis RCb <b> 1, while the opposite side, that is, the axially opposite side to the bolt hole 46 is open. And the bolt accommodating part 42 accommodates at least the polygonal part 22 of the fastening bolt 16 in the inner side in the state which fastening of the fastening bolt 16 was completed. In the present embodiment, the polygonal portion 22 and the fastening tool engaging portion 24 of the fastening bolt 16 are accommodated. Specifically, the bolt accommodating portion 42 is composed of a side wall 48 disposed around the bolt axis RCb1 so as to surround the polygonal portion 22 and the tightening tool engaging portion 24. The polygonal portion 22 and the tightening tool engaging portion 24 are accommodated in the container.

  The opening 44 is formed on the side of the bolt housing part 42. Specifically, it is composed of a rectangular opening hole formed in a part of the side wall 48 of the bolt accommodating portion 42. A view for explaining the opening 44 is shown in FIG. FIG. 12 is a view showing a state in which the loosening tool 50 is engaged with the fastening bolt 16 of FIG. 1, and the bolt housing portion 42 is a cross section perpendicular to the bolt shaft centers RCb1 and RCb2, that is, in FIG. It is a figure represented by CC arrow cross section. A loosening tool 50 (see FIG. 12) that is engaged with the polygonal portion 22 of the fastening bolt 16 from the radial direction is inserted into the opening 44. The opening 44 allows the loosening tool 50 inserted through the opening 44 to rotate together with the fastening bolt 16 in order to loosen the fastening bolt 16. More specifically, the opening 44 is provided only between the one side end 44a and the other side end 44b of the opening hole constituting the opening 44 of the loosening tool 50 engaged with the polygonal portion 22. The bolt engaging portion 50a is allowed to rotate around the bolt axis RCb1. That is, when the operator loosens the tightened fastening bolt 16, the operator loosens the loosening tool 50 toward the one side end 44a and inserts it into the opening 44 while inserting it into the polygonal portion 22 of the fastening bolt 16. Engage the loosening tool 50 and rotate the loosening tool 50 in the loosening direction (arrow ARLS direction in FIG. 12) of the fastening bolt 16 within the allowable rotational range WDpm (see FIG. 12) allowed by the opening 44. Thus, the fastening bolt 16 can be loosened.

  Specifically, a pair of parallel surfaces of a plurality of pairs of parallel surfaces constituting the outer peripheral side surface of the polygonal portion 22 of the fastening bolt 16 rotate around the bolt axis RCb1 to the position of another adjacent parallel surface. If the angle is a unit rotation angle AG1rt (see FIG. 11), the opening width in the circumferential direction of the bolt axis RCb1 of the opening 44 (hereinafter referred to as the circumferential opening width), that is, from the one side end 44a to the other. The distance around the bolt axis RCb1 to the side end 44b allows the loosening tool 50 to rotate the fastening bolt 16 at a rotation angle equal to or greater than the unit rotation angle AG1rt while allowing the unit rotation. The opening width (interval) prevents rotation of the loosening tool 50 that rotates the fastening bolt 16 at a rotation angle that is twice or more the angle AG1rt. For example, the unit rotation angle AG1rt is 45 ° (= 360 ° / 8) if the cross section perpendicular to the bolt axis RCb1 of the polygonal portion 22 forms a regular octagon. In the case of a regular polygon having a square shape, the angle is 60 ° (= 360 ° / 6). In this embodiment, the cross section of the polygonal portion 22 is a regular octagonal shape that forms a regular octagon. Therefore, unless the loosening tool 50 is engaged with the polygonal portion 22 once, the polygonal portion 22 is inserted through the opening 44 and into the polygonal portion 22. The fastening bolt 16 can be rotated by 45 ° or more by the engaged loosening tool 50, but the fastening bolt 16 cannot be rotated by 90 ° (= 45 ° × 2) or more. The opening 44 restricts the rotation angle of the loosening tool 50. That is, the loosening tool 50 engaged with the polygonal portion 22 has the permissible distance from the rotation position at which the bolt engagement portion 50a abuts against the one side end 44a to the rotation position at which the bolt engagement portion 50a abuts against the other side end 44b. Since the rotation angle is limited within the rotation range WDpm, the side wall 48 constituting the protector member 38 functions as a work angle suppression wall that limits (suppresses) the rotation angle of the loosening tool 50. The loosening tool 50 may be a special tool, but is, for example, a spanner according to a predetermined public standard (for example, JIS B 4630). In FIG. 12, the loosening tool 50 is illustrated by a solid line in a state where the bolt engaging portion 50a hits the one side end 44a, and two states in which the bolt engaging portion 50a hits the other side end 44b. This is illustrated by the chain line.

  As shown in FIGS. 3 and 10, the fastening bolt 16 that fastens the bracket 12 to the transmission case 14, that is, the fastening bolt 16 after the fastening is completed, includes a tool engaging portion 54 and a remaining portion 56. The shear bolt 52 is screwed. The tool engaging portion 54 and the residual portion 56 are arranged in series with each other and are integrally formed. The fastening bolt 16 has a predetermined shear torque or more between the tool engaging portion 54 and the residual portion 56. When the torque is applied, the tool engaging portion 54 and the remaining portion 56 are broken at the boundary between the tool engaging portion 54 and the remaining portion 56, so that the tool engaging portion 54 and the remaining portion 56 are separated from each other. The tool engaging portion 54 has a regular hexagonal column shape, and is engaged with a work tool such as a spanner for fastening the fastening bolt 16. The residual portion 56 has a residual head portion 56a having an outer diameter larger than the hole diameter of the bottom screw hole 30 of the fastening bolt 16 and an axial thickness larger than the depth of the polygonal hole 26 in series from the tool engaging portion 54 side. And a residual screw portion 56b formed with a male screw screwed into the bottom screw hole 30. 3 shows the shear bolt 52 in a state where the tool engaging portion 54 and the remaining portion 56 are separated from each other, and the perspective view of FIG. 10 shows the shear bolt 52 before the separation at the bottom screw hole 30. Represents a state of being screwed together.

  Specifically, the shear bolt 52 is screwed into the bottom screw hole 30 of the fastening bolt 16 after the fastening bolt 16 is completely fastened. Then, after the shear bolt 52 is fastened to the fastening bolt 16, a torque greater than the predetermined shear torque is applied to the tool engagement portion 54 of the shear bolt 52, whereby the boundary between the tool engagement portion 54 and the remaining portion 56. The tool engaging portion 54 is removed while the remaining portion 56 is fixed in the polygonal hole 26 of the fastening bolt 16. As a result, the fastening tool engaging portion 24 of the fastening bolt 16 is in a state in which the remaining portion 56 is fixed in the polygonal hole 26 as shown in FIG. If the residual portion 56 remains fixed in the polygonal hole 26 in this way, the residual head 56a closes the polygonal hole 26 in detail, so that the tightening tool 27 can be engaged with the polygonal hole 26. As a result, it becomes impossible to loosen the fastening bolt 16 by the fastening tool 27. That is, the residual portion 56 of the shear bolt 52 that is sheared in a state where the fastening bolt 16 is screwed into the bottom screw hole 30, that is, the residual portion 56 left in the polygonal hole 26 is tightened. The tightening tool 27 engaged with the attachment tool engaging portion 24 functions as a loosening operation prevention device that prevents the fastening bolt 16 from rotating in the loosening direction from the fastened state.

  According to the present embodiment, the fastening bolt 16 has an even angle cross section perpendicular to the threaded portion 20 screwed into the threaded hole 15 of the transmission case 14 that is the fastened member and the bolt shaft centers RCb1 and RCb2. A polygonal part 22 having a polygonal shape and a fastening tool 27 provided on the opposite side of the screw part 20 in the axial direction across the polygonal part 22 are engaged from the axial direction to rotate the fastening bolt 16 in the fastening direction. And a tightening tool engaging portion 24. In the bolt fastening structure 8, a through hole 46 a as a bolt hole through which the screw portion 20 of the fastening bolt 16 is inserted is formed in the cover bottom portion 40, and the polygonal portion 22 of the fastening bolt 16 is accommodated and is connected to the cover bottom portion 40. A protector member 38 that is open on the opposite side in the axial direction, and a leg portion 32b that is interposed between the cover bottom portion 40 of the protector member 38 and the polygonal portion 22 of the fastening bolt 16 and that protrudes toward the cover bottom portion 40 side. The remaining portion 56 as a loosening operation prevention device that prevents the fastening bolt 16 from being rotated in the loosening direction from the fastened state by the washer 32 having the fastening tool engaging portion 24 and the fastening tool 27 engaged. And has. The protector member 38 is formed on the side, and allows the loosening tool 50 engaged with the polygonal portion 22 to pass therethrough and allow the loosening tool 50 to rotate together with the fastening bolt 16 to loosen the fastening bolt 16. And an insertion hole 47a that is formed in the cover bottom 40 and through which the leg 32b of the washer 32 is inserted. The bracket 12 as a fastening member receives a through hole 46b as a bolt hole through which the screw portion 20 of the fastening bolt 16 is inserted, and a leg portion 32b of the washer 32, and around the bolt shaft centers RCb1 and RCb2 of the leg portion 32b. And an insertion hole 47b as a locking portion that prevents the rotation of the rotation.

  With the above-described configuration, the bolt fastening structure 8 of the present embodiment is a tightening tool from the axial direction of the fastening bolt 16 (the direction of the bolt axis RCb1, RCb2) when the fastening bolt 16 is fastened. 27, the fastening bolt 16 cannot be loosened, and when the fastening bolt 16 is loosened by the loosening tool 50, the rotation angle of the loosening tool 16 is limited by the circumferential opening width of the opening 44. Therefore, it is difficult to loosen the fastening bolt 16 as compared with the case where it is assumed that the fastening bolt 27 is loosened by the fastening tool 27 on the assumption that the loosening operation preventing device is not provided. Therefore, it is possible to ensure a high antitheft effect that prevents the SBW motor 10 and the bracket 12 from being unduly removed from the transmission case 14. If the loosening tool 50 is engaged with the polygonal part 22, the work of loosening the fastening bolt 16 can be reliably advanced, and the fastening bolt 16 is rotated in the loosening direction as the work progresses. Therefore, it is possible to ensure sufficient workability during vehicle maintenance and the like. A washer 32 inserted between the cover bottom portion 40 of the protector member 38 and the polygonal portion 22 of the fastening bolt 16 includes a leg portion 32b, and the leg portion 32b is formed on the cover bottom portion 40 of the protector member 38. The protector member 38 can be prevented from rotating with respect to the bracket 12 by being inserted into the insert hole 47a and received in the insert hole 47b formed in the bracket 12, so that the protector member 38 is secured to the bracket 12 (the bracket body 36). Therefore, the manufacturing cost can be reduced.

  According to this embodiment, the fastening tool engaging portion 24 of the fastening bolt 16 is provided in the polygonal hole 26 opened in the axial direction and into which the fastening tool 27 is fitted, and the bottom surface 28 of the polygonal hole 26. The bottom screw hole 30 is provided. The loosening prevention device comprises a remaining portion 56 of a shear bolt 52 that is sheared in a state where the fastening bolt 16 is screwed into the bottom screw hole 30 in a tightened state. Therefore, the tightening tool 27 cannot be easily and reliably engaged with the tightening tool engaging portion 24 by the remaining portion 56 of the shear bolt 52, and the tightening bolt 16 cannot be loosened by the tightening tool 27. Is possible.

  According to this embodiment, the cross section perpendicular to the axis of the polygonal portion 22 is a regular polygonal shape, and the circumferential opening width of the opening 44 constitutes the outer peripheral side surface of the polygonal portion 22 of the fastening bolt 16. The turn of the loosening tool 50 for rotating the fastening bolt 16 at a rotation angle equal to or greater than the unit rotation angle AG1rt at which a pair of parallel surfaces of the plurality of pairs of parallel surfaces rotate to the position of another adjacent parallel surface. The opening width prevents the rotation of the loosening tool 50 that rotates the fastening bolt 16 at a rotation angle more than twice the unit rotation angle AG1rt while allowing the movement. Accordingly, the tightening bolt 16 can be surely loosened by the loosening tool 50 engaged with the polygonal portion 22, and the rotation angle of the loosening tool 50 by the opening 44 is limited, so that the high antitheft effect is achieved. It is possible to secure.

  According to the present embodiment, the protector member 38 and the fastening bolt 16 are provided only at a part of a plurality (three places) of bolt fastening locations including the fastening location by the fastening bolt 16. Therefore, a portion where the protector member 38 and the fastening bolt 16 are not provided among the plurality of bolt fastening portions while ensuring the high antitheft effect by the fastening bolt 16, the bolt accommodating portion 42, and the opening 44. Specifically, at the bolt fastening location on the bolt shaft center RCb3, it is possible to ensure high workability of loosening the bolt when removing the bracket 12 from the transmission case 14.

  According to this embodiment, the outer diameter of the tightening tool engaging portion 24 is larger than the dimension between the pair of parallel surfaces of the polygonal portion 22, that is, the two-surface width dimension GPs in FIGS. Therefore, for example, in FIG. 3, the tightening tool engaging portion 24 prevents the tool inserted from the opening hole opened in the axial direction of the bolt accommodating portion 42 from engaging with the polygonal portion 22 due to its outer shape. As a result, since the tool cannot be engaged with the polygonal portion 22 from the axial direction of the fastening bolt 16, the outer diameter of the fastening tool engaging portion 24 is smaller than the case where the outer surface width dimension GPs is smaller. It is possible to ensure a high anti-theft effect.

  According to the present embodiment, as shown in FIG. 1, the protector member 38 (the bolt accommodating portion 42 and the opening 44) is provided in the bracket 12 among a plurality of bolt fastening locations by the fastening bolt 16 or the hexagon bolt 18. In the two places where the protector member 38 is not provided on the bracket 12, the hexagon bolt 18 which is a standard bolt in accordance with a predetermined public standard is used. It is concluded. Accordingly, the number of special fastening bolts 16 used can be reduced as compared with the case where the fastening bolts 16 are used in common for all bolt fastening locations, so that the cost can be reduced.

  Next, another embodiment of the present invention will be described. In the following description of the embodiments, the same reference numerals are given to portions overlapping with each other, and the description thereof is omitted.

  The present embodiment (embodiment 2) is different from the above-described embodiment 1 in that a bracket 62 shown in FIG. 13 is provided instead of the bracket 12 shown in FIG. . FIG. 13 is a front view showing the bracket 62 alone in the same direction as FIG. The protector member 38 assembled to the bracket 62 is indicated by a broken line. As shown in FIG. 13, the bracket 62 of the present embodiment receives the leg portion 32b of the washer 32 and rotates the leg portion 32b about the axis of the fastening bolt 16 (bolt axis centers RCb1, RCb2). A notch 64 is provided as a locking portion for blocking. That is, at least around the bolt shaft centers RCb1 and RCb2 of the leg portion 32b of the washer 32 at a position corresponding to the insertion hole 47a formed in the cover bottom portion 40 in a state where the protector member 38 is provided at a correct position with respect to the bracket 62. A notch 64 having a configuration for preventing the rotation is formed. Specifically, the notch 64 is formed by opening an insertion hole 47b provided in the bracket 12 shown in FIG. In other words, the side walls at both ends in the longitudinal direction of the insertion hole 47b functioning as a configuration for preventing the rotation of the leg portion 32b of the washer 32 around the bolt axis RCb1 are extended to the outer peripheral end of the bracket 62. is there.

  In the state where the fastening bolt 16, the protector member 38, and the bracket 62 are assembled to each other, the insertion hole 47a of the cover bottom 40 has a notch 64 of the bracket 62 formed coaxially therewith as shown in FIG. The leg 32b of the washer 32 of the fastening bolt 16 is received. In other words, the leg portion 32 b of the washer 32 of the fastening bolt 16 is inserted through the insertion hole 47 a of the cover bottom portion 40 and the notch 64 of the bracket 62. With such a configuration, the fastening bolt 16, the protector member 38, and the bracket 62 are assembled to each other. As a result, the bracket 62 and the protector member 38 are attached to the transmission case 14 and fastened on the bolt axis RCb 1. When the fastening bolt 16 is completely fastened, the protector member 38 is prevented from rotating with respect to the bracket 62 by the insertion hole 47a of the cover bottom 40 and the leg portion 32b of the washer 32 inserted into the notch 64 of the bracket 62, that is, the bolt axis RCb1. It is possible to suppress the relative rotation around the center. That is, also in the present embodiment, similarly to the first embodiment, it is not necessary to weld the protector member 38 to the bracket 62, and the manufacturing cost can be reduced.

  This embodiment (Embodiment 3) differs from Embodiment 1 described above in that a protector member 68 shown in FIGS. 14 and 15 is provided instead of the protector member 38 shown in FIG. Mainly explained. FIG. 14 is a front view showing the protector member 68 alone in the same direction as FIG. 1, and the bracket 12 to which the protector member 68 is assembled is indicated by a broken line. FIG. 15 is a side view of the protector member 68 in the direction of arrow AR04 in FIG. As shown in these drawings, the protector member 68 of this embodiment includes a notch 70 as an insertion portion through which the leg portion 32 b of the washer 32 is inserted into the cover bottom portion 40. That is, the leg 32b of the washer 32 is inserted into a position corresponding to the insertion hole 47b formed in the bracket 12 in a state where the protector member 68 is provided at a correct position with respect to the bracket 12, and at least the leg 32b. A notch 70 is formed to prevent rotation around the bolt shaft centers RCb1 and RCb2. Specifically, the notch 70 is formed by opening an insertion hole 47a formed in the protector member 38 shown in FIG. In other words, the side walls at both ends in the longitudinal direction of the insertion hole 47a functioning as a configuration for preventing the rotation of the leg portion 32b of the washer 32 around the bolt axis RCb1 are extended to the outer peripheral end of the protector member 68. It is.

  At the side of the protector member 68, a loosening tool 50 engaged with the polygonal portion 22 of the fastening bolt 16 is inserted, and the loosening tool 50 rotates together with the fastening bolt 16 to loosen the fastening bolt 16. Is formed continuously to the opening opposite to the cover bottom 40 in the axial direction. Specifically, the opening 72 is formed by opening the opening 44 formed in the protector member 38 shown in FIG. 8 and the like on the opposite side in the axial direction with respect to the cover bottom 40. In other words, the side wall 48 is not provided on the opposite side of the cover bottom 40 with respect to the opening 72 at a position corresponding to the opening 72.

  In the state in which the fastening bolt 16, the protector member 68, and the bracket 12 are assembled to each other, the notch 70 of the cover bottom 40, together with the insertion hole 47b of the bracket 12 formed coaxially therewith, as shown in FIG. The leg 32b of the washer 32 of the fastening bolt 16 is received. In other words, the leg portion 32 b of the washer 32 of the fastening bolt 16 is inserted through the notch 70 of the cover bottom portion 40 and the insertion hole 47 b of the bracket 12. With such a configuration, the fastening bolt 16, the protector member 68, and the bracket 12 are assembled to each other, and thus the bracket 12 and the protector member 68 are attached to the transmission case 14 and fastened on the bolt axis RCb1. When the fastening bolt 16 is completely fastened, the protector member 68 is prevented from rotating with respect to the bracket 12 by the notch 70 of the cover bottom portion 40 and the leg portion 32b of the washer 32 inserted through the insertion hole 47b of the bracket 12, that is, the bolt axis RCb1. It is possible to suppress the relative rotation around the center. That is, also in the present embodiment, similarly to the first and second embodiments, it is not necessary to weld the protector member 68 to the bracket 12, and the manufacturing cost can be reduced.

  As described above, in the bolt fastening structure 8, when the fastening bolt 16 is fastened to the transmission case 14, the fastening tool 27 from the axial direction of the fastening bolt 16 (bolt shaft center RCb1, RCb2 direction). In some cases, the fastening bolt 16 cannot be loosened. Accordingly, when the fastening bolt 16 is loosened by the loosening tool 50, the loosening tool 16 must be inserted from the side of the protector member 68, and the side of the protector member 68 as shown in FIGS. Even if the opening 72 formed on the side is opened on the opposite side in the axial direction with respect to the cover bottom 40, the rotation angle of the loosening tool 16 is limited by the circumferential opening width of the opening 72. As compared with the case where it is assumed that the tightening tool 27 is used to loosen the fastening bolt 16 on the assumption that the loosening operation blocking device is not provided, the fastening bolt 16 is difficult to loosen. If the loosening tool 50 is engaged with the polygonal part 22, the work of loosening the fastening bolt 16 can be reliably advanced, and the fastening bolt 16 is rotated in the loosening direction as the work progresses. Therefore, it is possible to ensure sufficient workability during vehicle maintenance and the like. Therefore, it is possible to ensure a high antitheft effect that prevents the SBW motor 10 and the bracket 12 from being unduly removed from the transmission case 14. In other words, the configuration in which the opening 72 formed on the side of the protector member 68 is opened on the opposite side in the axial direction with respect to the cover bottom 40 also exhibits the advantageous effect of the present invention.

  Here, the aspect in which the protector member 38 of Example 1 is assembled to the bracket 62 of Example 2 and the aspect in which the protector member 68 of Example 3 is assembled to the bracket 12 of Example 1 have been described. The protector member 68 according to the third embodiment may be assembled to the bracket 62 according to the second embodiment. Also in such an aspect, the fastening bolt 16, the protector member 68, and the bracket 62 are assembled to each other, that is, the bracket 62 and the protector member 68 are attached to the transmission case 14 so that the bolt shaft center RCb1 is mounted. When the fastening bolt 16 is completely fastened, the protector member 68 is prevented from rotating with respect to the bracket 62 by the notch 70 of the cover bottom 40 and the leg 32b of the washer 32 inserted through the notch 64 of the bracket 62, that is, the bolt axis RCb1. It is possible to suppress the relative rotation around the center.

  As mentioned above, although the Example of this invention was described in detail based on drawing, this invention is applied also in another aspect.

  For example, in the above-described embodiment, the polygonal portion 22 of the fastening bolt 16 has a regular polygonal shape in which a cross section perpendicular to the bolt shaft centers RCb1 and RCb2 forms a regular octagon, but a square, a regular hexagon, a regular decagon, Or the regular polygon shape which makes a regular dodecagon etc. may be sufficient. It is also conceivable that the cross section of the polygonal portion 22 is an even-numbered polygonal shape that is not a regular polygonal shape.

  In the above-described embodiment, the locking agent is applied to the screw portion 20 of the fastening bolt 16, but the locking agent may not be applied.

  In the above-described embodiment, the brackets 12 and 62 are bolted to the transmission case 14 at three locations, but may be bolted to 1, 2, or 4 or more locations.

  In the above-described embodiment, the fastening bolt 16 is used for fixing the SBW motor 10 and the brackets 12 and 62 to the transmission case 14, but may be used for other purposes.

  In the above-described embodiment, the fastening bolts 16 are used in two of the three bolt fastening locations of the brackets 12 and 62 with respect to the transmission case 14, but the fastening bolt 16 is used in at least one location. The fastening bolt 16 may be used at all three bolt fastening locations. The use location and number of the fastening bolts 16 may be appropriately determined based on the balance between the anti-theft performance and workability during vehicle maintenance.

  In the above-described embodiment, the circumferential opening width of the polygonal portion 22 included in the fastening bolt 16 is the loosening tool 50 for turning the fastening bolt 16 at a turning angle that is twice or more the unit turning angle AG1rt. If the opening width restricts the rotation of the loosening tool 50 to a certain rotation angle, the balance between anti-theft performance and workability during vehicle maintenance is considered. The circumferential opening width may be an opening width that allows rotation of the loosening tool 50 that rotates the fastening bolt 16 at a rotation angle more than twice the unit rotation angle AG1rt. Absent.

  In the above-described embodiment, the washer 32 is provided with the L-shaped leg portion 32b. However, the shape of the washer leg portion is not necessarily limited to such a shape, such as a pin shape or a hook shape. Various aspects are possible. The washer 32 is provided with one leg 32b, but may be provided with two or more legs. In such an embodiment, a plurality of insertion portions and locking portions for receiving the plurality of washers legs are formed at corresponding positions in the protector members 38 and 68 and the brackets 12 and 62, respectively.

  In the above-described embodiment, the fastening bolt 16 has a shape as shown in FIG. 10, but other shapes are also conceivable. For example, the fastening bolt 16 may be replaced with any one of the bolts shown in FIGS. Here, each of the bolts in FIGS. 16 to 21 will be described in terms of differences from the fastening bolt 16. In this case, the points common to the fastening bolts 16 are omitted for the sake of brevity.

  The fastening bolt 310 of FIG. 16 includes a screw portion 312 corresponding to the screw portion 20 of the first embodiment, a polygon portion 314 corresponding to the polygonal portion 22 of the first embodiment, and the tightening tool assembly of the first embodiment in order from the bolt tip. A bolt body composed of a fastening tool engaging portion 316 corresponding to the joint portion 24 and a washer 318 corresponding to the washer 32 of the first embodiment are provided. The polygonal portion 314 has a regular polygonal shape in which a cross section perpendicular to the bolt axis of the fastening bolt 310 forms a regular hexagon. The fastening tool engaging portion 316 includes a hexagonal hole 320 like the fastening bolt 16, and the hexagonal hole 320 fastens the fastening tool 27 which is a hexagonal bar spanner fitted in the hexagonal hole 320. When the bolt 310 is rotated in the tightening direction, it engages with the tightening tool 27. On the other hand, the hexagonal hole 320 has a known one-way structure that does not engage with the fastening tool 27 when the fastening tool 27 is rotated in the loosening direction of the fastening bolt 310. In this loosening direction, the hole shape 320a to which the tightening tool 27 does not engage functions as the loosening operation prevention device. 16, 17, and 18 indicate hatching of the locking agent applied to the screw portions 312 and 412.

  The fastening bolt 350 in FIG. 17 is different from the fastening bolt 310 in that the polygonal portion 314 of the fastening bolt 310 in FIG. 16 is replaced with the polygonal portion 352, but is otherwise the same as the fastening bolt 310. It is. The polygonal part 352 in FIG. 17 has a regular polygonal shape in which a cross section perpendicular to the bolt axis of the fastening bolt 350 forms a regular decagon. The fastening bolt 350 has an advantage that the working time is longer than that of the fastening bolt 310 of FIG. 16 when the fastening bolt 350 after the fastening is loosened and the tool 50 is loosened. The cross section of the polygonal part 352 may be a regular polygon having a regular octagon or a dodecagon.

  The fastening bolt 410 in FIG. 18 includes a screw portion 412 corresponding to the screw portion 20 of the first embodiment, a polygon portion 414 corresponding to the polygonal portion 22 of the first embodiment, and the tightening tool assembly of the first embodiment in order from the bolt tip. A tightening tool engaging portion 416 corresponding to the joint portion 24 is provided. A washer 418 corresponding to the washer 32 of the first embodiment is provided. The threaded portion 412 and the polygonal portion 414 are configured integrally with each other, while the fastening tool engaging portion 416 is a separate part from the threaded portion 412 and the polygonal portion 414. The tightening tool engaging portion 416 has a hexagonal bolt shape, and is screwed into a screw hole formed on the axial end surface of the polygonal portion 414 and has a smaller diameter screw portion (not shown) than the screw portion 412. ) And a head 416a having a regular hexagonal column shape. The small-diameter screw portion and the screw portion 412 have the same screw tightening direction. The polygonal portion 414 has a regular polygonal shape in which a cross section perpendicular to the bolt axis of the fastening bolt 410 forms a regular hexagon. Unlike the first embodiment, the tightening tool engaged with the tightening tool engaging portion 416 is, for example, a box wrench. In the fastening bolt 410, when the fastening tool engaged with the head 416a of the fastening tool engaging portion 416 is rotated in the fastening direction of the fastening bolt 410, the fastening torque from the fastening tool is used. Is transmitted to the screw portion 412 and the polygonal portion 414 as they are. On the other hand, when the fastening tool is rotated in the loosening direction of the fastening bolt 410 after the fastening bolt 410 is completely fastened, the small-diameter screw portion of the fastening tool engaging portion 416 is smaller in diameter than the screw portion 412. Therefore, the fastening tool engaging portion 416 is loosened with respect to the polygonal portion 414 before the fastening bolt 410 is loosened with respect to the transmission case 14, and is engaged with the fastening tool engaging portion 416. In addition, the fastening bolt 410 cannot be loosened with the fastening tool. Therefore, in the fastening bolt 410, the fastening tool engaging portion 416 also has a function as the loosening operation prevention device.

  The fastening bolt 450 in FIG. 19 is basically the same as the fastening bolt 350 in FIG. 17, but a metal or resin cap 452 that covers the hexagonal hole 320 after the fastening bolt 450 is completely fastened is a fastening tool. It is attached to the engaging portion 454. Therefore, the tightening tool engaging portion 454 has a cylindrical shape so that the outer shape of the tightening tool engaging portion 454 can be attached to the cap 452, but is otherwise the same as the tightening tool engaging portion 316 of FIG. When the cap 452 is attached to the tightening tool engaging portion 454, the cap 452 is fitted to the tightening tool engaging portion 454 so that it cannot be easily removed. In this fastening bolt 450, in addition to the hole shape 320a of the hexagonal hole 320, the cap 452 also functions as the loosening operation prevention device.

  FIG. 20 is a cross-sectional view of the left half. A fastening bolt 510 shown in FIG. 20 includes a screw portion 512 corresponding to the screw portion 20 according to the first embodiment, a polygon portion 514 corresponding to the polygonal portion 22 according to the first embodiment, and the fastening tool assembly according to the first embodiment. A tightening tool engaging portion 516 corresponding to the joint portion 24 is provided. A washer 518 corresponding to the washer 32 of the first embodiment is provided. The screw part 512 and the polygonal part 514 are configured integrally with each other, while the tightening tool engaging part 516 is a separate part from the screw part 512 and the polygonal part 514. Specifically, the tightening tool engaging portion 516 is a hexagonal bolt having a male screw having a smaller diameter than the screw portion 512, and the tightening direction of the hexagonal bolt is the same as that of the screw portion 512. And the hexagon bolt which comprises the fastening tool engaging part 516 is screwed by the screw hole formed in the axial direction end surface of the polygonal part 514, Thereby, the head of the said hexagon bolt is bolt axis | shaft of the fastening bolt 510. A head cover member 520 surrounding the center and opening in the axial direction is fixed to the polygonal portion 514 together with the tightening tool engaging portion 516. The polygonal portion 514 has a regular polygonal shape in which a cross section perpendicular to the bolt axis of the fastening bolt 510 forms a regular hexagon. Unlike the first embodiment, the tightening tool engaged with the tightening tool engaging portion 516 is, for example, a box wrench. After completing the fastening of the fastening bolt 510, a metal or resin cap 522 that closes the opening of the head cover member 520 is fitted into the head cover member 520 from the axial direction. When the cap 522 is fitted inside the head cover member 520, the cap 522 is engaged with the head cover member 520 so as not to be removed inside the head cover member 520, and is axially moved from the head cover member 520. The head cover member 520 fits completely without protruding. Since the cap 522 is thus fitted into the head cover member 520, it is difficult to remove the cap 522 from the head cover member 520 after that, and the tightening tool is engaged with the tightening tool engaging portion 516. This makes it difficult to loosen the fastening bolt 510. Therefore, in the fastening bolt 510, the head cover member 520 and the cap 522 function as the loosening operation prevention device.

  FIG. 21 is a cross-sectional view of the entire left half and the upper part of the right half. A fastening bolt 550 shown in FIG. 21 includes a screw portion 552 corresponding to the screw portion 20 of the first embodiment, a polygon portion 554 corresponding to the polygonal portion 22 of the first embodiment, and the tightening tool assembly of the first embodiment in order from the bolt tip. A bolt body composed of a fastening tool engaging portion 556 corresponding to the joint portion 24 and a washer 558 corresponding to the washer 32 of the first embodiment are provided. The polygonal portion 554 has a regular polygonal shape in which a cross section perpendicular to the bolt axis of the fastening bolt 550 forms, for example, a regular octagon, a regular decagon, or a regular dodecagon. The tightening tool engaging portion 556 includes a hexagonal hole 320 including the hole shape 320a having the one-way structure in the same manner as the fastening bolt 310 of FIG. On the bottom surface of the hexagonal hole 320, a bottom screw hole 560, which is a stop hole formed including a female screw on the bolt shaft center, is provided, and after the one-way bolt cap 562 completes the fastening bolt 550 to be fastened. The bottom screw hole 560 is screwed. The one-way bolt cap 562 is a cross-recessed machine screw. The outer diameter of the head 564 is such that the head 564 opens the hexagonal hole 320 in a state where the one-way bolt cap 562 is screwed into the bottom screw hole 560. It is a size that covers the whole. Like the hexagonal hole 320, the cross hole 566 of the one-way bolt cap 562 is engaged with the tool only when the tool (cross screwdriver) fitted in the cross hole 566 is rotated in the tightening direction of the one-way bolt cap 562. The above-mentioned one-way structure is provided. Therefore, in the fastening bolt 550, the hole shape 320a of the hexagonal hole 320 and the one-way bolt cap 562 function as the loosening operation prevention device.

  In the above-described embodiment, the transmission case 14 includes the screw hole 15 into which the fastening bolt 16 is screwed. However, the through hole into which the screw portion 20 of the fastening bolt 16 is inserted instead of the screw hole 15. The brackets 12 and 62 may be fixed to the transmission case 14 by screwing the fastening bolts 16 and nuts. In such a case, a structure that makes it impossible or difficult to loosen the nut after completion of fastening is necessary.

  What has been described above is merely an embodiment, and the present invention can be implemented in variously modified and improved forms based on the knowledge of those skilled in the art.

  8: Bolt fastening structure 10: SBW motor (fastening member) 12, 62: Bracket (fastening member) 14: Transmission case (fastened member) 15: Screw hole 16, 310, 350, 410, 450, 510, 550: Fastening bolt 20,312,412,512,552: Screw part 22,314,352,414,514,554: Polygon part 24,316,416,454,516,556: Fastening tool engaging part 26: Polygon Hole 27: Tightening tool 28: Bottom surface 30: Bottom screw hole 32, 318, 418, 518, 558: Washer 32b: Leg 38, 68: Protector member 40: Cover bottom 44, 72: Opening 46: Bolt hole 47a : Insertion hole (insertion part) 47b: Insertion hole (locking part) 50: Loosening tool 52: Shear bolt G: Residual portion (loosening operation prevention device) 64: Notch (locking portion) 70: Notch (insertion portion) 320a: Hole shape (loosening operation prevention device) 416: Tightening tool engaging portion (loosening operation prevention device) 452: Cap (loosening operation blocking device) 520: Cover member (loosening operation blocking device) 522: Cap (loosening operation blocking device) 562: One-way bolt cap (loosening operation blocking device) RCb1, RCb2, RCb3: Bolt shaft center

Claims (5)

A bolt fastening structure for a vehicle in which a fastening member is fixed to a fastened member with a fastening bolt,
The fastening bolt is
A screw portion screwed into the screw hole of the fastened member;
A polygonal section having a polygonal cross section perpendicular to the axis of the fastening bolt;
A tightening tool engaging portion that is provided on the opposite side of the screw portion in the axial direction across the polygonal portion and that engages a tightening tool that rotates the tightening bolt in the tightening direction from the axial direction. ,
The bolt fastening structure is
A protector member in which a bolt hole into which a screw portion of the fastening bolt is inserted is formed in the bottom portion, accommodates a polygonal portion of the fastening bolt, and an axially opposite side with respect to the bottom portion opens.
A washer having a leg portion interposed between the bottom portion of the protector member and the fastening bolt and projecting toward the bottom portion;
A loosening operation preventing device that prevents the fastening tool engaged with the fastening tool engaging portion from rotating in the direction of loosening the fastening bolt from the fastened state.
The protector member is
An opening formed on a side and allowing a loosening tool engaged with the polygonal portion to be inserted and allowing the loosening tool to rotate with the fastening bolt to loosen the fastening bolt;
An insertion portion formed on the bottom and into which the leg portion of the washer is inserted,
The fastening member is
A bolt hole through which the threaded portion of the fastening bolt is inserted;
A bolt fastening structure for a vehicle, comprising: a locking portion that receives a leg portion of the washer and prevents rotation of the leg portion around an axis of the fastening bolt. The tightening tool engaging portion includes a polygonal hole that is opened in the axial direction and into which the tightening tool is fitted, and a bottom screw hole provided on a bottom surface of the polygonal hole.
The said loosening operation prevention apparatus consists of the residual part of the shearing bolt sheared in the state screwed together in the said bottom screw hole in the state which the said fastening bolt was fastened. Bolt fastening structure for vehicles. The polygonal shape in a cross section perpendicular to the axis of the polygonal part is an even polygonal regular polygonal shape,
The opening width in the circumferential direction of the axial center of the fastening bolt of the opening is the other parallel of a pair of parallel surfaces of a plurality of pairs of parallel surfaces constituting the outer peripheral side surface of the polygonal portion of the fastening bolt. While allowing the loosening tool to rotate the fastening bolt at a rotation angle equal to or greater than the unit rotation angle that rotates to the surface position, the rotation is twice or more the unit rotation angle. The bolt fastening structure for a vehicle according to claim 1 or 2, wherein the opening width is such that the loosening tool for turning the fastening bolt at an angle is prevented from turning.   The bolt fastening structure for a vehicle according to any one of claims 1 to 3, wherein the protector member is provided only at a part of a plurality of bolt fastening locations including a fastening location by the fastening bolt. .   The bolt fastening structure for a vehicle according to any one of claims 1 to 4, wherein an outer diameter of the tightening tool engaging portion is larger than a dimension between a pair of parallel surfaces of the polygonal portion. .

Images