JP6536737B2 - Fastening structure and electric turbocharger - Google Patents

Description

  The present disclosure relates to a fastening structure for fastening a first conductive member and a second conductive member, and an electric turbocharger equipped with the fastening structure.

  As such a fastening structure, the structure described in Patent Document 1 is known. In this structure, the terminal plate at the tip of the L-shaped electrode plate and the external electrode plate are fastened by screwing a bolt and a nut. A nut holder is disposed inside the bent portion of the electrode plate. The nut holder is provided with a recess for receiving the nut so as to prevent the rotation of the nut. A part of the nut holder is embedded in the resin molded product. The nut holder and the electrode plate are insert-molded into a resin molded product while maintaining a predetermined distance.

Patent No. 5640871

  A space for fastening the first conductive member and the second conductive member may be a limited narrow space. For example, if the plate-shaped first conductive member extends at a constant distance from the wall and the distance is narrow, fastening using a bolt and a nut is difficult. Although it is conceivable to screw and fasten a bolt directly to the wall, if the wall has a thickness corresponding to the length of the bolt, the wall will be enlarged. In a narrow space, it is also difficult to hold the nut between the first conductive member and the wall.

  The present disclosure describes a fastening structure capable of easily fastening the first conductive member and the second conductive member even in a narrow space, and an electric turbocharger provided with the fastening structure.

A fastening structure according to an aspect of the present disclosure is a fastening structure for fastening a first conductive member and a second conductive member at a position separated from a wall, the fastening structure facing a surface of the wall and facing the surface A plate-shaped first conductive member extending at a constant distance between the first conductive member, a second conductive member disposed on the opposite side of the surface of the first conductive member, and fastened to the first conductive member; Between the member and the wall portion, a nut disposed around an axis extending in the thickness direction of the first conductive member, and disposed along the axis so as to penetrate the first conductive member and the second conductive member And a nut holder provided between the nut and the wall to accommodate at least a portion of the wall of the nut and restricting rotation of the nut, the wall including a nut A recess into which the bottom of the holder fits is formed, and the first conductive member Nut holder movable length in the axial direction with respect to contact with the nut from the surface of the wall, rather smaller than the length in the axial direction to the bottom surface of the waiting bottom fitted into the recess, recess to the surface The region in which is provided is larger than the bottom of the nut holder and longer in the first direction orthogonal to the axial direction, and the nut holder has no nut between the first conductive member and the wall. The bottom portion can be fitted into the recess at a first position not interfering with the first conductive member, and the nut can be slid to a second position centered on the axis, with the recess fitted.

  According to one aspect of the present disclosure, even in a narrow space, the first conductive member and the second conductive member can be facilitated by cooperation between the nut holder fitted in the recess and the nut accommodated in the nut holder. Can be concluded.

FIG. 1 is a cross-sectional view showing an electric turbocharger according to an embodiment of the present disclosure. FIG. 2 is a cross-sectional view showing the fastening structure in FIG. 3 (a) is a plan view of the nut holder in FIG. 2, FIG. 3 (b) is a front view of the nut holder, FIG. 3 (c) is a perspective view of the surface side of the nut holder, and FIG. It is a perspective view of the back side of a holder. 4 (a) shows the size and shape of the recess and the bottom, FIG. 4 (b) shows the nut holder placed in the first position, and FIG. 4 (c) shows the second position. FIG. 4D is a view showing a nut holder, and FIG. 4D is a view showing a fastening structure in which fastening with a bolt is performed. It is sectional drawing which expands and shows the fastening structure of FIG.

  A fastening structure according to an aspect of the present disclosure is a fastening structure for fastening a first conductive member and a second conductive member at a position separated from a wall, the fastening structure facing a surface of the wall and facing the surface A plate-shaped first conductive member extending at a constant distance between the first conductive member, a second conductive member disposed on the opposite side of the surface of the first conductive member, and fastened to the first conductive member; Between the member and the wall portion, a nut disposed around an axis extending in the thickness direction of the first conductive member, and disposed along the axis so as to penetrate the first conductive member and the second conductive member And a nut holder provided between the nut and the wall to accommodate at least a portion of the wall of the nut and restricting rotation of the nut, the wall including a nut A recess into which the bottom of the holder fits is formed, and the first conductive member Nut holder movable length in the axial direction with respect to contact with the nut from the surface of the wall portion, smaller than the length in the axial direction to the bottom surface of the fitting waiting bottom in the recess.

  According to this fastening structure, a fixed space exists between the plate-like first conductive member and the surface of the wall. Within this spacing, a nut and a nut holder for receiving at least a portion of the nut are provided. The nut holder fits into a recess formed in the wall. As a result, the distance between the nut holder and the first conductive member is increased, and the nut can be easily disposed on the lower side (the back surface side, that is, the wall portion side) of the first conductive member. When the bolt is screwed into the nut, the rotation of the nut is regulated by the nut holder. Therefore, even when the tool space can not be secured on the nut side, the fastening operation can be performed without any problem. When the bolt is screwed onto the nut to fasten the first conductive member and the second conductive member, the nut is drawn to the first conductive member side and abuts on the first conductive member. In this state, the length by which the nut holder can move in the axial direction is smaller than the length at which the bottom of the nut holder fits into the recess, so the bottom of the nut holder leaves the recess while fitting into the recess I can not do it. This can prevent the nut holder from coming out of the recess. By cooperation between the nut holder fitted in the recess and the nut accommodated in the nut holder, the first conductive member and the second conductive member can be easily fastened even in the case of a space where the above-mentioned fixed distance is narrow. is there.

  In some embodiments, the area in which the recess is provided to the surface is larger than the bottom of the nut holder and longer in the first direction orthogonal to the axial direction, and the nut holder has the bottom recessed In the fitted state, the nut is slidable to a first position where the nut deviates from the axis and to a second position where the nut is disposed about the axis. According to this configuration, the nut holder can be installed at the first position while avoiding interference between the nut and the first conductive member. By moving the nut holder to the second position while the bottom portion of the nut holder is fitted in the recess, the nut is disposed about the axis at the lower side of the first conductive member. This enables smoother fastening work.

  In some embodiments, the recess has a width slightly larger than the bottom of the nut holder in a second direction orthogonal to the axial direction and the first direction, and is opposed in the second direction on both sides of the recess The pair of side surfaces provided as described restricts the movement of the bottom in the second direction. According to this configuration, the nut holder is guided in the first direction by the long groove-like recess. Therefore, the above-mentioned slide operation is reliable and easy.

  In some embodiments, the plurality of first conductive members are provided, and the plurality of first conductive members are arranged to be spaced apart from one another in the first direction. In this case, when the nut holder is in the first position, the nut can be positioned in the gap between the adjacent first conductive members. This gap can be used to install the nut while avoiding interference between the nut and the first conductive member.

  In some embodiments, the bottom of the nut holder is smaller than the outer projection of the nut holder when projected in the axial direction, and the nut holder projects axially from the flat surface facing the surface of the wall and from the flat surface And a bottom portion. In this case, since the bottom of the nut holder is smaller than the outer diameter of the nut holder, the depression provided in the wall can be reduced.

  The nut holder is provided with a nut accommodating portion having a shape corresponding to the outer shape of the nut. In this case, the rotation of the nut can be easily restricted.

  An electric turbocharger according to an aspect of the present disclosure includes a housing including a wall, a stator portion housed in the housing, and any of the fastening structures described above, and the first conductive member is mounted on the housing. It is a 1st bus bar attached and electrically connected to a stator part, and the 2nd electric conduction member is the 2nd bus bar by the side of the power supply fastened to a 1st bus bar. According to this electric supercharger, the first bus bar connected to the stator portion and the second bus bar on the power supply side can be easily fastened even in a narrow space on the wall of the housing.

  A fastening structure according to another aspect of the present disclosure is a fastening structure for fastening a first conductive member and a second conductive member at a position separated from a wall, the fastening structure facing a surface of the wall, and a surface And a second conductive member disposed opposite to the surface of the first conductive member and fastened to the first conductive member, and a first conductive member extending at a fixed distance between the second conductive member and the first conductive member; Between the member and the wall portion, a nut disposed around an axis extending in the thickness direction of the first conductive member, and disposed along the axis so as to penetrate the first conductive member and the second conductive member And a nut holder provided between the nut and the wall for receiving at least a part of the wall side of the nut and having a non-circular nut receiving portion corresponding to the outer shape of the nut. The wall is shaped like a recess into which the bottom of the nut holder fits The movable length of the nut holder in the axial direction with respect to the nut in contact with the first conductive member is the axial length from the surface of the wall to the bottom of the bottom fitted in the recess Too small.

  In some embodiments, the area provided with a recess with respect to the surface is larger than the bottom of the nut holder and longer in the first direction orthogonal to the axial direction than the bottom and the length in the first direction of the area The difference between the height and the length of the bottom in the first direction is equal to or greater than the width of the nut.

  Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the description of the drawings, the same elements will be denoted by the same reference symbols and redundant description will be omitted.

  An electric turbocharger 1 according to a first embodiment will be described with reference to FIG. As shown in FIG. 1, the electric turbocharger 1 is applied to an internal combustion engine of a vehicle or a ship, for example. The electric turbocharger 1 includes a compressor 7. The electric supercharger 1 rotates the compressor impeller 8 by the interaction of the rotor portion 13 and the stator portion 14 to compress fluid such as air and generate compressed air.

  The electric supercharger 1 includes a rotating shaft 12 rotatably supported in the housing 2 and a compressor impeller 8 fixed to a tip (one end) 12 a of the rotating shaft 12. The housing 2 includes a motor housing 3 for housing the rotor portion 13 and the stator portion 14 and a base housing 4 for closing the opening at the other end (right side in the drawing) of the motor housing 3. At one end side (the left side in the figure) of the motor housing 3, a compressor housing 6 for housing the compressor impeller 8 is provided. The compressor housing 6 includes an inlet 9, a scroll portion 10 and an outlet 11.

  The rotor portion 13 is fixed at the axial center of the rotating shaft 12 and includes one or more permanent magnets (not shown) attached to the rotating shaft 12. The stator portion 14 is fixed to the inner surface of the motor housing 3 so as to surround the rotor portion 13 and includes a coil portion (not shown) formed by winding the conducting wire 14 a. When an alternating current flows in the coil portion of the stator portion 14 through the conducting wire 14a, the rotary shaft 12 and the compressor impeller 8 rotate integrally as a result of the interaction between the rotor portion 13 and the stator portion 14. When the compressor impeller 8 rotates, the compressor impeller 8 sucks the external air through the suction port 9, compresses the air through the scroll portion 10, and discharges the air from the discharge port 11. The compressed air discharged from the discharge port 11 is supplied to the aforementioned internal combustion engine.

  The electric supercharger 1 includes two bearings 20 which are press-fitted to the rotating shaft 12 and rotatably support the rotating shaft 12 with respect to the housing 2. The bearing 20 supports the rotary shaft 12 at both ends. One bearing 20 is provided at the end of the motor housing 3 on the compressor impeller 8 side. The other bearing 20 is provided on a support wall 23 projecting in the axial direction of the rotary shaft 12 from the base housing 4.

  The base housing 4 is provided with a mechanism for supplying a driving current to the stator portion 14. The base housing 4 includes a disk-shaped end wall 21 closing an opening on the other end side of the motor housing 3 and a peripheral wall 22 connecting the outer periphery of the end wall 21 and the motor housing 3. In the peripheral wall portion 22, a conducting wire 14 a connected to the stator portion 14 is accommodated. The support wall portion 23 described above protrudes from the center of the end wall portion 21 to the inside in the axial direction of the rotation shaft 12. End wall portion 21 is made of, for example, aluminum.

  On the outer side (right side in the drawing) of the end wall portion 21, a module 30 for housing control components such as an inverter is fixed. In the housing 2, the first bus bar (first conductive member) 31 is electrically connected to the above-described conducting wire 14 a. The first bus bar 31 passes through the through hole 21 b (see FIG. 2) of the end wall 21 and protrudes to the outside of the end wall 21. On the other hand, the second bus bar (second conductive member) 32 extends out from the module 30 toward the first bus bar 31. These first bus bars 31 and second bus bars 32 are made of, for example, copper. The first bus bar 31 and the second bus bar 32 are conductive members for supplying a drive current. The first bus bar 31 is a conductive member on the motor side, and the second bus bar 32 is a conductive member on the module 30 side (power supply side).

  In the electric turbocharger 1, the three first bus bars 31 and the three second bus bars 32 are provided (see FIG. 4 (d)). The three first bus bars 31 extend parallel to one another. The three second bus bars 32 extend in parallel to one another. The three pairs of first bus bars 31 and second bus bars 32 are spaced apart from one another in a predetermined direction (first direction). This separation distance may be determined based on the size of the nut 37 described later. The first direction is a direction parallel to the surface 21 a of the end wall 21. The three pairs of first bus bars 31 and second bus bars 32 are fastened by the fastening structure A of the present embodiment. The number of first bus bars 31 and second bus bars 32 may be changed according to the type of motor. For example, only one first bus bar 31 and only one second bus bar 32 may be provided.

  Each of the first bus bar 31 and the second bus bar 32 has a long plate shape. The thickness of the first bus bar 31 is larger than the thickness of the second bus bar 32. In addition, the thickness of the 1st bus-bar 31 and the 2nd bus-bar 32 is not specifically limited, A various aspect may be taken. The three pairs of first bus bars 31 and second bus bars 32 are fastened by a fastening structure A at a position separated from the end wall portion 21 in the axial direction of the rotary shaft 12. In the fastening structure A, the end wall portion 21 is used as a floor plate portion for fastening and fixing the first bus bar 31 and the second bus bar 32. The thickness of the end wall portion 21 is very thin for the purpose of weight reduction and thickness reduction. The fastening structure A suitably realizes fastening between the first bus bar 31 and the second bus bar 32 with respect to such an end wall portion 21 by a configuration to be described later.

  As shown in FIG. 2, the first bus bar 31 protruding vertically from the end wall portion 21 is bent in an L-shape. The flat plate-like tip 31 a of the first bus bar 31 faces the flat surface 21 a of the end wall 21. The distal end portion 31 a is substantially parallel to the surface 21 a of the end wall portion 21 and extends at a constant distance from the surface 21 a. A resin-made sleeve portion 33 is provided between the first bus bar 31 and the end wall portion 21. The first bus bar 31 is fixed to the end wall portion 21 by the sleeve portion 33 and the fixing portion 34 provided at one end of the sleeve portion 33. The sleeve portion 33 insulates the first bus bar 31 from the end wall portion 21 made of aluminum.

  The second bus bar 32 extends, for example, in a straight line, and faces the surface 21 a of the end wall 21. The second bus bar 32 is substantially parallel to the surface 21 a of the end wall 21 and extends at a constant distance from the surface 21 a. The second bus bar 32 is disposed on the side opposite to the surface 21 a of the end wall portion 21 with respect to the first bus bar 31. The flat tip 32a overlaps the upper surface side of the tip 31a. A through hole 31 b is provided in the end portion 31 a of the first bus bar 31, and a through hole 32 b is provided in the end portion 32 a of the second bus bar 32. The through holes 31 b and the through holes 32 b overlap and are continuous.

  The shaft portion 36 b of the bolt 36 is inserted through the through hole 31 b and the through hole 32 b. In other words, the shaft portion 36 b of the bolt 36 is disposed so as to pass through the tip 31 a of the first bus bar 31 and the tip 32 a of the second bus bar 32. In addition, a nut 37 is disposed between the tip 31 a and the end wall 21. The through hole 31 b of the first bus bar 31, the through hole 32 b of the second bus bar 32, the nut 37, and the shaft portion 36 b of the bolt 36 are all disposed around the axis L. The male screw portion of the shaft portion 36 b is screwed into the female screw portion of the nut 37. The shaft 36 b is screwed into the nut 37 so that the tip thereof protrudes from the nut 37.

  The axis L described above extends in the thickness direction of the first bus bar 31 and the second bus bar 32. That is, the axis L is substantially orthogonal to the end wall portion 21 (surface 21 a), and is parallel to the axial direction of the rotation axis 12. The shaft 36 b of the bolt 36 is disposed along the axis L. The head 36 a of the bolt 36 is located on the opposite side of the second bus bar 32 from the nut 37. The distal end portion 31 a of the first bus bar 31 and the distal end portion 32 a of the second bus bar 32 are fastened by the bolt 36 and the nut 37. In this fastened state, the nut 37 is drawn to the tip end 31 a side by screwing the male thread of the shaft 36 b with the female thread of the nut 37, and abuts on the tip 31 a. In the fastening structure A, three fastening portions of the same structure are provided. Each fastening portion includes a tip 31 a of the first bus bar 31, a tip 32 a of the second bus bar 32, a nut 37, and a bolt 36. The fastening structure A includes three parallel axis lines L aligned in a first direction in which the three first bus bars 31 are aligned (a direction perpendicular to the sheet of FIG. 2 and the left and right direction in FIG. 3A). The first direction is orthogonal to each axis L.

  The fastening structure A includes a nut holder 40 for holding the nut 37. The nut holder 40 is provided between the nut 37 and the end wall 21. One nut holder 40 is commonly provided to a plurality of (three in the fastening structure A) fastening portions. The nut holder 40 holds the nuts 37 particularly when assembling the fastening structure A. Hereinafter, with reference to FIG. 2 and FIG. 3 (a)-FIG.3 (d), the nut holder 40 is demonstrated in detail.

  As shown in FIGS. 3A to 3D, the nut holder 40 has a flat block shape as a whole. The nut holder 40 includes a flat plate-like main body 41 and a projection (bottom) 46 projecting from the main body 41 in the direction of the axis L. Nut holder 40 is made of resin, for example, and may be formed by integral molding. The nut holder 40 can insulate the end wall portion 21 of the base housing 4 from the respective first bus bars 31 (or the respective nuts 37 or the respective bolts 36). The nut holder 40 may be made of metal and the surface thereof may be coated with an insulating material. The nut holder 40 may be made of ceramic or the like.

  The main body portion 41 has a rectangular shape elongated in the first direction, and for example, four corner portions thereof are rounded. Body portion 41 includes a flat front surface 41 a facing front end 31 a of first bus bar 31 and a flat rear surface (flat surface) 41 b facing front surface 21 a. The main body portion 41 is provided with three nut accommodating portions 44 formed on the surface 41 a side and three through holes 42 formed on the back surface 41 b side. The respective nut accommodating portions 44 and the respective through holes 42 are formed around the axis L direction, and are in communication with each other. The nut accommodating portion 44 and the through holes 42 are equally spaced apart in the first direction, corresponding to the three first bus bars 31.

  The nut accommodating portion 44 accommodates at least a portion of the nut 37. More specifically, the nut accommodating portion 44 accommodates a half portion on the end wall 21 side of the nut 37 (see FIG. 2). As shown in FIGS. 3A and 3C, the nut accommodating portion 44 corresponds to the outer shape of the nut 37 and has, for example, a hexagonal shape. In other words, the nut housing portion 44 has a hexagonal column shape, and a hexagonal engaging wall 43 is provided around the nut housing portion 44. On the other hand, the through hole 42 has a cylindrical shape and is smaller than the nut housing portion 44 in the radial direction. The through hole 42 is larger than the diameter of the shaft portion 36 b of the bolt 36 and can accommodate the tip of the shaft portion 36 b protruding from the nut 37 (see FIG. 2). An annular step 48 (see FIG. 5) is formed between the nut accommodation portion 44 and the through hole 42. The present invention is not limited to the case where the through hole 42 is provided in the main body 41, and a bottomed hole communicating with the nut housing 44 may be provided in the main body 41. In this case, the hole may be able to accommodate the tip of the shaft 36 b protruding from the nut 37.

  A part of the nut 37 is accommodated in the nut accommodation portion 44 and is mounted on the annular step portion 48 described above when the fastening structure A is assembled. Since the nut housing portion 44 is slightly larger than the nut 37, a slight gap is formed between the engagement wall surface 43 and the nut 37. The engagement wall 43 slightly allows the rotational movement of the nut 37, but restricts further rotation of the nut 37 after the nut 37 abuts. The nut 37 is accommodated in the nut holder 40 by the nut accommodation portion 44, the through hole 42, and the engagement wall 43, and when the bolt 36 is screwed on the nut 37, the rotation of the nut 37 is restricted. Even in a narrow space into which a tool for fixing the nut 37 can not be inserted, the rotation of the nut 37 can be prevented, and screwing of the bolt 36 to the nut 37 can be suitably performed.

  The protrusion 46 is in the form of a long thin plate, and the end in the first direction is rounded. As shown in FIG. 3 (b), the protrusion 46 protrudes from the back surface 41 b of the main body 41 in the direction of the axis L. The thickness of the protrusion 46 is smaller than the thickness of the main body 41. The protrusion 46 is slightly smaller than the main body 41. That is, the protrusion 46 is smaller than the outer shape when the nut holder 40 (main body 41) is projected in the direction of the axis L.

  As shown in FIG. 3 (d), the protrusion 46 has straight side portions 46a, 46a connecting the rounded ends 46b, 46b in the first direction and the ends 46b, 46b. And. The opposing side portions 46a, 46a are parallel to each other. The protrusion 46 overlaps only the central through hole 42 of the three through holes 42 in the first direction. In other words, the ends 46 b and 46 b of the protrusion 46 do not reach the two through holes 42 located at both ends in the first direction. The protrusion 46 is smaller than the width of the main body 41 in a second direction orthogonal to the first direction and orthogonal to the axis L. In other words, the side portions 46 a and 46 a of the projecting portion 46 are formed inside the pair of parallel long sides of the main body portion 41 (see FIG. 5).

  The protrusion 46 further includes a flat bottom surface 46 c that is an end surface in the direction of the axis L. The bottom surface 46 c is parallel to the front surface 41 a of the main body portion 41 and parallel to the back surface 41 b.

  As shown in FIGS. 4A and 5, the end wall 21 of the base housing 4 is formed with a groove 26 in which the protrusion 46 of the nut holder 40 is fitted. The groove 26 is recessed in the direction of the axis L from the surface 21 a. The groove 26 has a pair of straight side portions 26a, 26b, 26b connected between the rounded first and second ends 26b, 26b in the first direction and the first and second ends 26b, 26b. And 26a. The opposing side portions 26a, 26a are parallel to each other.

  The area where the groove 26 is provided for the surface 21 a is larger than the protrusion 46 of the nut holder 40. The area is longer than the protrusion 46 in the first direction. More specifically, the length between the first and second ends 26b and 26b in the first direction of the groove 26 (width W2 in FIG. 4A) is between the ends 46b and 46b of the projection 46. It is larger than the length (width W1 of FIG. 4 (a)). The semicircular end portions 46b, 46b can be in contact with the semicircular end portions 26b, 26b. The difference between the width W2 and the width W1 is, for example, equal to or greater than the width of the nut 37. Here, in the case of, for example, a hexagonal nut, the width of the nut 37 is the distance between the two opposing faces (two-sided width). In the case of the nut 37 having a polygonal shape, the width of the nut 37 may be a two-face width, but is not limited to the two-face width and may be a diagonal distance. In the case of a circular nut 37, the width of the nut 37 is a diameter. The difference between the width W2 and the width W1 corresponds to the movable range of the nut holder 40 in the first direction.

  On the other hand, the groove 26 has a width slightly larger than the protrusion 46 of the nut holder 40 in the second direction (vertical direction in FIG. 4A). More specifically, the length between the side portions 26 a, 26 a in the second direction of the groove 26 is slightly larger than the length between the side portions 46 a, 46 a of the protrusion 46. The pair of side surface portions 26 a, 26 a provided opposite to each other in the second direction on both sides of the groove 26 abuts on the side portions 46 a, 46 a of the projecting portion 46, thereby forming the projecting portion 46 and thus the second holder 46. Regulate movement in two directions.

  With the above configuration, the nut holder 40 is movable in the first direction with the protrusion 46 fitted in the groove 26. The groove 26 guides the nut holder 40 in the first direction while restricting the movement of the nut holder 40 in the second direction. The nut holder 40 is movable between a first position in which the first end 46b abuts on the first end 26b and a second position in which the second end 46b abuts on the second end 26b. is there. When the nut holder 40 is in the first position, the nut 37 housed in the nut housing portion 44 deviates from the axis L and is positioned between the tip portions 31a (see FIG. 4B). When the nut holder 40 is in the second position, the nut 37 housed in the nut housing portion 44 is disposed about the axis L and located below the tip portion 31a (see FIG. 4C). Thus, the nut holder 40 is guided by the groove 26 and is movable to the first position and the second position. When the nut is in the desired position when the first or second end 46b abuts on the first or second end 26b, the assembling workability of the fastening structure A is improved.

  The first position is not limited to the position of the nut holder 40 when the first end 46 b abuts on the first end 26 b. The nut holder 40 may be in the first position when the first end 46b is separated from the first end 26b, and the nut 37 may be separated from the axis L and positioned between the tip 31a. The second position is not limited to the position of the nut holder 40 when the second end 46 b abuts on the second end 26 b. When the second end 46b is away from the second end 26b, the nut holder 40 is in the second position, and the nut 37 is disposed about the axis L and located below the tip 31a. It is also good.

  As shown in FIG. 5, in the fastening state in which the tip end 31 a of the first bus bar 31 and the tip end 32 a of the second bus bar 32 are fastened, the nut 37 is an external thread of the shaft 36 b in the internal thread of the nut 37. By being screwed together, it is drawn to the tip portion 31a side and abuts on the tip portion 31a. Further, the back surface 41 b of the nut holder 40 can be in contact with the surface 21 a of the end wall portion 21. Although the protrusion 46 is fitted in the groove 26, the bottom surface 46 c of the protrusion 46 is separated from the bottom surface 26 c of the groove 26. The nut holder 40 is not fixed anywhere, and is movable in the direction of the axis L between the nut 37 and the surface 21 a.

  Here, the length by which the nut holder 40 can move in the direction of the axis L is smaller than the length by which the protrusion 46 of the nut holder 40 fits into the groove 26. More specifically, the length (corresponding to the height H1 shown in FIG. 5) by which the nut holder 40 can move in the direction of the axis L with respect to the nut 37 in contact with the first bus bar 31 is the surface 21a of the end wall portion 21. Is smaller than the length in the direction of the axis L (corresponding to the height H2 shown in FIG. 5) from the bottom surface 46c of the protrusion 46 fitted in the groove 26 to the bottom surface 46c. This height relationship prevents the nut holder 40 from falling off.

  Next, an assembling method of the fastening structure A will be described with reference to FIGS. 4 (a) to 4 (d). First, as shown in FIG. 4B, the three first bus bars 31 in the assembled state are connected to the conducting wire 14a and pass through the through holes 21b. It is fixed. In this state, the distance between the through hole 31 b and the surface 21 a of the end wall portion 21 is a narrow distance. The nut holder 40 is fitted in the groove 26 at a position where the nut 37 and the tip portion 31 a of the first bus bar 31 do not interfere with each other. At this time, since the nut holder 40 is in the first position described above, the nut 37 can be installed using the gap between the tip portions 31a. At this time, the nut holder 40 may be installed first, and then the nut 37 may be fitted, or these may be installed with the nut 37 fitted in the nut holder 40.

  Next, as shown in FIG. 4C, the nut holder 40 is slid. When the nut holder 40 moves to the second position, the nut 37 is disposed on the axis L at the lower side of the tip 31a. At this time, it is not necessary to adjust the position of the nut 37 strictly. The holes of the nut 37 generally overlap the through holes 31b and the through holes 32b, and it is sufficient for the positional accuracy to such an extent that the bolt 36 can be inserted and assembled. That is, the nut holder 40 may not be exactly aligned with the second position so that the nut 37 is disposed about the axis L.

  Next, as shown in FIG. 4D, the tip 32a of the second bus bar 32 is overlapped with the tip 31a, and the bolt 36 is screwed into the nut 37. At this time, the nut 37 is fixed in the rotational direction by the nut holder 40, and the nut holder 40 is also fixed in the rotational direction. Therefore, as the bolt 36 is rotated, the nut 37 floats up. The fastening structure A is completed by completing the fastening. As shown in FIG. 5, in the state where the bolt 36 is tightened, the nut holder 40 can float by an amount (height H1) of the floating margin of the nut 37 (height H1), but the floating margin protrudes The nut holder 40 is not removed from the base housing 4 because it is set smaller than the fitting depth (height H 2) of the portion 46.

  According to the fastening structure A of the present embodiment, a constant interval exists between the plate-like first bus bar 31 and the surface 21 a of the end wall portion 21. Within this spacing, a nut 37 and a nut holder 40 housing at least a portion of the nut 37 are provided. The nut holder 40 is fitted into the groove 26 formed in the end wall portion 21. As a result, the distance between the nut holder 40 and the first bus bar 31 is increased, and the nut 37 can be easily disposed on the lower side of the first bus bar 31 (on the back surface side, that is, on the end wall portion 21 side). When the bolt 36 is screwed into the nut 37, the rotation of the nut 37 is regulated by the nut holder 40. Therefore, even when the tool space can not be secured on the nut 37 side, the fastening operation can be performed without any problem. When the bolt 36 is screwed to the nut 37 and fastening of the first bus bar 31 and the second bus bar 32 is performed, the nut 37 is screwed by the male screw of the shaft 36 b into the female screw of the nut 37. The first bus bar 31 is drawn to abut on the first bus bar 31. In this state, the height H1 at which the nut holder 40 can move in the direction of the axis L is smaller than the height H2 at which the protrusion 46 of the nut holder 40 fits into the groove 26, the protrusion 46 of the nut holder 40 Is stuck in the groove 26 and can not get out of the groove 26. Thereby, the nut holder 40 is prevented from coming out of the groove 26. By cooperation between the nut holder 40 fitted in the groove 26 and the nut 37 accommodated in the nut holder 40, the first bus bar 31 and the second bus bar 32 can be easily made even in the space where the above-mentioned fixed interval is narrow. It is possible to conclude the This fastening structure A is effective only when the thickness of the end wall portion 21 can not be secured as in the electric supercharger 1, since it is sufficient to provide the groove 26 of a small depth in the end wall portion 21. . As a result, it can also contribute to thinning of the end wall portion 21. As in the present embodiment, in the case where the end wall portion 21 facing the first bus bar 31 is present and the space therebetween is limited, the fastening structure A is particularly effective. Moreover, since the assembly structure of the first bus bar 31 is already fixed to the end wall portion 21, it is difficult to widen the space. However, according to the fastening structure A, the first bus bar 31 and the second bus bar 32 can be easily fastened by sequentially assembling the nut holder 40 and the nut 37 after mounting. As the bolt 36 is inserted from the wide space side, the assembly operation is also easy.

  As described above, the movable range (the difference between the width W 2 and the width W 1) of the nut holder 40 is equal to or greater than the width of the nut 37. The nut holder 40 is slidable to a first position in which the nut 37 is separated from the axis L and a second position in which the nut 37 is disposed about the axis L in a state where the protrusion 46 is fitted in the groove 26 . As the nut holder 40 slides, the nut 37 moves by a length equal to or greater than the width of the nut 37 itself. Therefore, the nut holder 40 can be installed at the first position while avoiding the interference between the nut 37 and the first bus bar 31 at the second position. By moving the nut holder 40 to the second position while the protrusion 46 of the nut holder 40 is fitted in the groove 26, the nut 37 is disposed about the axis L at the lower side of the first bus bar 31. . This enables smoother fastening work.

  The pair of side surface portions 26 a, 26 a of the groove 26 restricts the movement of the protrusion 46 in the second direction, so the nut holder 40 is guided by the elongated groove 26 in the first direction. Therefore, the above-mentioned slide operation is reliable and easy.

  Since the plurality of first bus bars 31 are arranged separately from one another in the first direction, the nuts 37 can be positioned in the gaps between the adjacent first bus bars 31 when the nut holder 40 is at the first position. . The nut 37 can be installed while avoiding the interference between the nut 37 and the first bus bar 31 using this gap.

  The nut holder 40 includes a projection 46 as a bottom. Since the protrusion 46 is smaller than the outer shape of the nut holder 40, the groove 26 provided in the end wall 21 may be small. This configuration is particularly effective when the area of the end wall 21 is limited.

  The nut holder 40 is provided with the nut accommodating portion 44 having a shape corresponding to the outer shape of the nut 37, so that the rotation of the nut 37 can be easily restricted.

  According to the electric supercharger 1 having the fastening structure A, the first bus bar 31 connected to the stator portion 14 and the second bus bar 32 on the power supply side also in a narrow space on the end wall portion 21 of the base housing 4 And can be easily concluded.

  As mentioned above, although embodiment of this indication was described, this invention is not limited to the said embodiment. For example, the invention is not limited to the case of using the bolt 36 having the head portion 36a and the shaft portion 36b, and fastening may be performed by a rod-like bolt (stud bolt) and a plurality of nuts. In this case, not the head portion 36 a of the bolt 36 but an additional nut is disposed on the second bus bar 32.

  In the nut holder 40, the hexagonal nut accommodating portion 44 is provided as a shape corresponding to the outer shape of the nut 37, but the present invention is not limited thereto. The nut housing portion 44 can be, for example, a non-circular shape such as a polygon such as a triangle, square, or star shape, or an oval shape.

  Also, for example, a protrusion that can contact when the nut 37 rotates may be provided on either the nut housing portion 44 or the nut 37. Alternatively, a protrusion such as a pin may be provided on one of the nut housing portion 44 and the nut 37, and a groove may be provided on the other to engage with the protrusion. In this case, when the nut 37 rotates, the side surface of the protrusion and the side surface of the groove contact each other.

  In addition, when the bolt 36 is screwed into the nut 37, the nut holder 40 only has to be able to regulate the rotation of the nut 37 to an extent that the nut holder 40 withstands a predetermined fastening torque. The nut holder 40 may not have a shape corresponding to the outer shape of the nut 37. For example, the nut holder 40 may be circular and the nut 37 may be non-circular or polygonal, and a restriction member such as a pin may be separately provided in the minimum gap.

  In the above embodiment, the first bus bars 31 are arranged in the first direction. However, if it is possible to secure the positional accuracy to such an extent that the nut holder 40 slides and the bolt 36 can be inserted into the nut 37 and assembled. The bus bar 31 may not be disposed on a straight line. In addition, if the arrangement of the through holes 31 b at the tip end portion of the first bus bar 31 corresponds to the arrangement of the nuts 37, for example, by adjusting the size of the nut holder 40, the first position of the polygonal line or polygonal apex etc. The directions may be offset from one another.

  The arrangement of the plurality of fastening portions (arrangement of the nut accommodating portion 44) and the sliding direction of the nut holder 40 can be changed as appropriate. The plurality of nut accommodating portions 44 provided in the nut holder 40 may be arranged at the vertex positions of a polygonal line or polygonal shape. In this case, the nut holder 40 is slidable in the first direction. The plurality of nut receiving portions 44 may be disposed along a circular arc. In this case, the nut holder 40 can slide in the arc direction.

  The direction in which the grooves 26 extend may be any direction. Unlike the grooves 26 described above, the grooves may extend in the second direction. Also, it may be a groove extending in a curvilinear direction along a circular arc having a center on the second direction side instead of the linear direction. Instead of the protrusion 46, two cylindrical protrusions may be provided at both ends of the nut holder 40. No protrusion or protrusion may be provided on the nut holder 40, and the entire bottom of the nut holder 40 may be fitted into the recess.

  The end wall portion 21 may be provided with a cylindrical or polygonal cylindrical recess instead of the elongated groove 26. A mechanism for preventing rotation of the nut holder 40 may be provided, but may not be provided.

  The present invention is not limited to the case where the nut holder 40 slides, and the nut holder may be immovable and may be provided with a long groove in which the nut can move (insert) with respect to the nut holder.

  The fastening structure of the present invention is not limited to the electric turbocharger 1, and any structure may be applied as long as the conductive members are electrically connected at a position close to the wall. For example, a battery may be employed. Further, the invention is not limited to the portion for supplying the drive current, but can be employed in a conductive portion for transmitting an electric signal.

  According to some aspects of the present disclosure, the first electrically conductive member and the second electrically conductive member are formed by the cooperation of a nut holder that fits into the recess even in a narrow space, and a nut housed in the nut holder. Can be easily concluded.

Reference Signs List 1 electric supercharger 2 housing 3 motor housing 4 base housing 6 compressor housing 7 compressor 8 compressor impeller 14 stator portion 21 end wall portion (wall portion)
21a surface 26 groove (dent)
26a side surface portion 31 first bus bar (first conductive member)
32 second bus bar (second conductive member)
36 bolt 37 nut 40 nut holder 41 main body 41 a front surface 41 b back surface (flat surface)
43 engaging wall surface 44 nut accommodating portion 46 projecting portion (bottom)
46c bottom surface A fastening structure H1 height (length)
H2 height (length)
L axis

Claims (9)

A fastening structure for fastening a first conductive member and a second conductive member at a position separated from a wall portion, the fastening structure comprising:
A plate-shaped first conductive member facing the surface of the wall and extending at a constant distance from the surface;
The second conductive member disposed opposite to the surface of the first conductive member and fastened to the first conductive member;
A nut disposed around an axis extending in a thickness direction of the first conductive member between the first conductive member and the wall portion;
A bolt disposed along the axis so as to penetrate the first conductive member and the second conductive member, and screwed to the nut;
A nut holder provided between the nut and the wall to accommodate at least a portion of the nut on the wall side and restrict rotation of the nut;
The wall is formed with a recess into which the bottom of the nut holder fits.
The movable length of the nut holder in the axial direction with respect to the nut in contact with the first conductive member is from the surface of the wall to the bottom of the bottom fitted in the recess. axial rather smaller than the length,
The region where the recess is provided with respect to the surface is larger than the bottom of the nut holder and longer than the bottom in a first direction orthogonal to the axial direction.
The bottom portion of the nut holder can be fitted in the recess at a first position where the nut does not interfere with the first conductive member without the gap between the first conductive member and the wall portion, and the nut holder fits in the recess Fastening structure , wherein the nut is slidable to a second position centered on the axis when in the closed position . The recess has a width slightly larger than the bottom of the nut holder in a second direction orthogonal to the axial direction and the first direction, and both sides of the recess face each other in the second direction. a pair of side portions provided so as to regulates the movement of the second direction of the bottom, the fastening structure according to claim 1. A plurality of first conductive members are provided,
The plurality of the first conductive member, are arranged spaced from each other in the first direction, the fastening structure according to claim 1 or 2. The bottom portion of the nut holder is smaller than an outer shape when the nut holder is projected in the axial direction,
The fastening structure according to any one of claims 1 to 3 , wherein the nut holder includes a flat surface facing the surface of the wall portion and the bottom portion protruding in the axial direction from the flat surface. . The fastening structure according to any one of claims 1 to 4 , wherein the nut holder is provided with a nut accommodating portion having a shape corresponding to the outer shape of the nut. A housing including the wall;
A stator portion housed in the housing;
A fastening structure according to any one of claims 1 to 5 ;
The first conductive member is a first bus bar attached to the housing and electrically connected to the stator portion,
The electric supercharger, wherein the second conductive member is a second bus bar on a power supply side fastened to the first bus bar. A fastening structure for fastening a first conductive member and a second conductive member at a position separated from a wall portion, the fastening structure comprising:
A plate-shaped first conductive member facing the surface of the wall and extending at a constant distance from the surface;
The second conductive member disposed opposite to the surface of the first conductive member and fastened to the first conductive member;
A nut disposed around an axis extending in a thickness direction of the first conductive member between the first conductive member and the wall portion;
A bolt disposed along the axis so as to penetrate the first conductive member and the second conductive member, and screwed to the nut;
A nut holder provided between the nut and the wall to accommodate at least a portion of the nut on the wall side and restrict rotation of the nut;
The wall is formed with a recess into which the bottom of the nut holder fits.
The movable length of the nut holder in the axial direction with respect to the nut in contact with the first conductive member is from the surface of the wall to the bottom of the bottom fitted in the recess. Less than the axial length,
The region where the recess is provided with respect to the surface is larger than the bottom of the nut holder and longer than the bottom in a first direction orthogonal to the axial direction.
The nut holder is slidable to a first position in which the nut is separated from the axis and a second position in which the nut is disposed about the axis, with the bottom portion fitted in the recess.
A plurality of first conductive members are provided,
The fastening structure , wherein the plurality of first conductive members are arranged separately from each other in the first direction . A fastening structure for fastening a first conductive member and a second conductive member at a position separated from a wall portion, the fastening structure comprising:
A plate-shaped first conductive member facing the surface of the wall and extending at a constant distance from the surface;
The second conductive member disposed opposite to the surface of the first conductive member and fastened to the first conductive member;
A nut disposed around an axis extending in a thickness direction of the first conductive member between the first conductive member and the wall portion;
A bolt disposed along the axis so as to penetrate the first conductive member and the second conductive member, and screwed to the nut;
A nut holder provided between the nut and the wall to receive at least a portion of the nut on the wall side and having a non-circular nut receiving portion corresponding to the outer shape of the nut;
The wall is formed with a recess into which the bottom of the nut holder fits.
The movable length of the nut holder in the axial direction with respect to the nut in contact with the first conductive member is from the surface of the wall to the bottom of the bottom fitted in the recess. axial rather smaller than the length,
The region where the recess is provided with respect to the surface is larger than the bottom of the nut holder and longer than the bottom in a first direction orthogonal to the axial direction.
The bottom portion of the nut holder can be fitted in the recess at a position where the nut does not interfere with the first conductive member without the gap between the first conductive member and the wall portion, and the nut holder fits in the recess Fastening structure , wherein in the state said nut is slidable to a position centered on said axis . The region where the recess is provided with respect to the surface is larger than the bottom of the nut holder and longer than the bottom in a first direction orthogonal to the axial direction.
The fastening structure according to claim 8, wherein a difference between a length of the region in the first direction and a length of the bottom in the first direction is equal to or greater than a width of the nut.

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