JP6334302B2 - Fastening jig and rotating body manufacturing method - Google Patents

Description

  The present invention relates to a fastening jig and a method for manufacturing a rotating body.

  Conventionally, as a fastening jig for screwing and fastening a compressor impeller of a centrifugal compressor to a rotating shaft, a tool hanging part on which a tool for rotating the fastening jig is hung, and a plurality of extending parts from the tool hanging part A fastening jig provided with a rod-like protrusion is known (for example, see Patent Document 1). A plurality of holes corresponding to the rod-shaped protrusions are formed at the tip of the compressor wheel, and a fastening jig is installed so that the rod-shaped protrusions are inserted into the holes, and the tool is rotated on the tool hanging portion. As a result, the compressor wheel is screwed to the rotating shaft.

Japanese Patent No. 5067208

  In this type of fastening jig, it is desired to further improve the strength so as not to break even when a large fastening torque is applied. It is also desirable that the fastening jig can be easily manufactured by cutting. Therefore, an object of the present invention is to provide a fastening jig that improves strength and has good workability, and a method of manufacturing a rotating body using the same.

  The fastening jig of the present invention is a fastening jig that is interposed between a compressor impeller and a tool of a centrifugal compressor and screwed and fastened to the rotary shaft of the centrifugal compressor. A tool hanging portion on which a tool is hung and rotated, a connector extending from the tool hanging portion in the rotation axis direction of the tool hanging portion, and fitted into a fastening hole provided at a tip portion of the compressor impeller, The connector extends on the rotation axis in the direction of the rotation axis and is inserted into the center of the fastening hole, and protrudes from the center shaft portion in the radial direction of the tool hook and rotates. A projecting ridge portion extending in the axial direction and engaging with a torque transmission groove provided in the tightening hole, and the tool hook portion and the connector are integrally formed by cutting, and the central shaft portion The radius of curvature of the connecting portion with the ridge is larger than 1/8 of the length of the connector in the rotation axis direction. .

  The connector of the fastening jig includes a central shaft portion on the rotational axis, and has a structure in which a protruding portion protrudes from the central shaft portion in the rotational radial direction. Due to the structure in which the central shaft portion exists on the rotation axis, the cross-sectional area of the connector can be increased, and the strength of the connector against rotation can be improved. In addition, since the radius of curvature of the roundness of the connecting portion between the central shaft portion and the ridge portion is larger than 1/8 of the length in the rotation axis direction of the connector, it usually has a diameter of 1/4 or more of the length. The roundness of the connecting portion can be processed at a time using an end mill.

  Moreover, as a specific configuration, in the fastening jig of the present invention, the ridge portion may include an outer surface forming a cylindrical surface protruding in a direction away from the central shaft portion. Moreover, a protruding item | line part may further be provided with the connection plane which connects between a connection part and an outer surface.

  A method of manufacturing a rotating body according to the present invention includes a rotating shaft, a turbine impeller provided at one end of the rotating shaft, and a compressor impeller provided at the other end of the rotating shaft, and includes a centrifugal compressor. A manufacturing method for manufacturing a rotating body incorporated in a feeder, wherein the central shaft portion of any of the above-described fastening jigs is inserted into the center of the fastening hole and the protruding portion is engaged with the torque transmission groove. The jig is inserted into the fastening hole of the compressor impeller, and the tool is put on the tool hook of the fastening jig and rotated around the rotation axis. A screwing and fastening step of screwing and fastening to the rotating shaft.

  According to this manufacturing method, since the compressor wheel is screwed and fastened to the rotating shaft using the fastening jig whose strength of the connector against rotation is improved, the fastening jig can be used even if the tightening torque increases. The screw fastening is possible without destroying.

  According to the present invention, it is possible to provide a fastening jig that improves strength and has good workability, and a method for manufacturing a rotating body using the same.

It is sectional drawing which shows an example of the supercharger with which the jig | tool for fastening of this invention is applied. It is a perspective view which shows the compressor impeller of a supercharger. It is a front view which shows the front-end | tip vicinity of a compressor impeller. (A) is the front view which shows the jig | tool for fastening of this embodiment, (b) is the side view, (c) is the perspective view. (A) is a cross-sectional view perpendicular to the rotation axis in the vicinity of the convex portion of the fastening jig, and (b) is a diagram showing the relationship between the convex portion of the fastening jig and the torque transmission groove of the fastening hole. It is sectional drawing orthogonal to a rotating shaft line. (A)-(d) is a front view which shows each modification of the jig | tool for fastening. (A) is a front view of the fastening hole corresponding to one of the fastening jigs of a modification. (B) is sectional drawing which shows the convex stripe part vicinity of the modification of the jig | tool for fastening.

  Hereinafter, an example of a supercharger to which the fastening jig of the present invention is applied will be described with reference to the drawings.

  As shown in FIG. 1, the supercharger 1 includes a turbine 2 and a compressor 3 (centrifugal compressor). The turbine 2 includes a turbine housing 4 and a turbine impeller 6 housed in the turbine housing 4. The compressor 3 includes a compressor housing 5 and a compressor impeller 7 housed in the compressor housing 5. The turbine impeller 6 is provided at one end of the rotating shaft 14, and the compressor impeller 7 is provided at the other end of the rotating shaft 14. A bearing housing 13 is provided between the turbine housing 4 and the compressor housing 5. The rotating shaft 14 is rotatably supported by the bearing housing 13 via the bearing 15, and the rotating body 12 including the rotating shaft 14, the turbine impeller 6 and the compressor impeller 7 rotates around the rotation axis A as a unit. .

  The turbine housing 4 is provided with an exhaust gas inlet 8 and an exhaust gas outlet 10. Exhaust gas discharged from an internal combustion engine (not shown) flows into the turbine housing 4 through the exhaust gas inlet 8 to rotate the turbine impeller 6, and then to the outside of the turbine housing 4 through the exhaust gas outlet 10. leak.

  The compressor housing 5 is provided with a suction port 9 and a discharge port 11. When the turbine impeller 6 rotates as described above, the compressor impeller 7 rotates via the rotating shaft 14. The rotating compressor wheel 7 sucks external air through the suction port 9, compresses it, and discharges it from the discharge port 11. The compressed air discharged from the discharge port 11 is supplied to the internal combustion engine described above.

  Subsequently, the rotating body 12 will be further described. As described above, the rotating body 12 includes the turbine impeller 6, the rotating shaft 14, and the compressor impeller 7, and is built in the supercharger 1. The rotating body 12 also includes a collar 18 that is attached to the rotating shaft 14 and that engages with the thrust bearing 13 a of the bearing housing 13. The turbine impeller 6 is welded to one end of the rotating shaft 14 so that the turbine impeller 6 and the rotating shaft 14 are formed as a single body.

  The compressor wheel 7 shown in FIG. 2 is made of, for example, an aluminum alloy, and includes a hub 16 attached to the rotating shaft 14 and a plurality of blades 17 disposed on the outer peripheral surface of the hub 16 in the rotating circumferential direction. ing. The compressor wheel 7 has a solid structure. Specifically, a blind screw hole 7b (see FIG. 1) is provided at the rear end portion of the compressor wheel 7, and the other end of the rotary shaft 14 is screwed into the blind screw hole 7b. A compressor impeller 7 is attached to the rotary shaft 14. The rotating shaft 14 does not penetrate the hub 16, and the hub 16 is solid on the tip side of the blind screw hole 7b. According to this solid structure, the strength of the compressor impeller 7 can be increased as compared with a structure in which the rotary shaft is passed through the hollow portion of the compressor impeller.

  When the compressor impeller 7 is screwed and fastened to the rotating shaft 14 during manufacture of the rotating body 12 or during maintenance, the compressor impeller 7 itself needs to be rotated with respect to the rotating shaft 14. Specifically, a tightening hole 21 is provided in the center of the tip portion 7 a of the compressor impeller 7. When the compressor impeller 7 is screwed and fastened to the rotary shaft 14, a fastening jig 30 (see FIG. 4) is inserted into the fastening hole 21, and a tool (for example, a hexagon wrench) is inserted into the fastening jig 30. And the compressor wheel 7 is rotated with respect to the rotating shaft 14.

  The fastening hole 21 and the fastening jig 30 will be described with reference to FIGS. FIG. 3 is a front view showing the vicinity of the tip 7 a of the compressor impeller 7. The tightening hole 21 includes a main hole portion 22 formed in the center of the tip end portion 7a, and a plurality (four in this example) of torque transmission grooves 23 formed at equal intervals on the peripheral edge portion of the main hole portion 22. It has. The inner side surface 22a of the main hole portion 22 forms a cylindrical surface with the rotation axis A as an axis. The torque transmission groove 23 is a U groove formed so as to be recessed radially outward from the inner side surface 22a, and transmits a tightening torque from a fastening jig 30 described later. The inner side surface 23 a of the torque transmission groove 23 extends in the direction of the rotation axis A and forms a cylindrical surface having a smaller radius of curvature than the main hole portion 22. Thus, since the inner surface of the fastening hole 21 is composed of two types of cylindrical surfaces, the fastening hole 21 can be formed with only two types of drills. The central axis of the cylindrical surface constituting the inner side surface 23 a of the torque transmission groove 23 is located slightly inside the cylindrical surface constituting the inner side surface 22 a of the main hole 22.

  On the other hand, the fastening jig 30 is used by being interposed between the compressor impeller 7 and the tool. 4A is a front view showing the fastening jig 30, FIG. 4B is a side view thereof, and FIG. 4C is a perspective view thereof. As shown in the figure, the fastening jig 30 includes a tool hanging portion 39 on which a tool is hung, and a connector 31 that extends from the tool hanging portion in the rotation axis X direction and is fitted into the tightening hole 21. I have. The tool hook 39 and the connector 31 are integrally formed by cutting. The tool hanging portion 39 has a substantially regular hexagonal column, and can be used for hanging a fastening tool such as a hexagon wrench. The tool hanging portion 39 is rotated around the rotation axis X with the tool hung thereon. In the following description, the terms “rotational circumferential direction”, “rotational radial direction”, and the like simply correspond to rotation around the rotation axis X.

  The connector 31 includes a central shaft portion 32 and a protruding strip portion 33 formed around the central shaft portion 32. The central shaft portion 32 extends from the tool hook portion 39 in the direction of the rotational axis X on the rotational axis X, and is inserted into the center of the main hole portion 22 of the fastening hole 21. The central shaft portion 32 has a cylindrical shape, and the outer surface 32a of the central shaft portion 32 forms a cylindrical surface. The protruding portion 33 protrudes from the central shaft portion 32 in the rotational radial direction of the tool hook portion 39. The ridge 33 extends in the rotation axis X direction and engages with the torque transmission groove 23 of the tightening hole 21. The outer surface 33 a of the ridge 33 forms a cylindrical surface having a smaller radius of curvature than the central shaft portion 32.

  The connecting portion 34 between the central shaft portion 32 and the ridge portion 33 is rounded (rounded). The curvature radius R of the roundness (R) is larger than 1/8 of the length L of the connector 31 in the rotation axis X direction. Specifically, as shown in FIG. 5A, a cross-sectional shape in the vicinity of the ridge 33 and orthogonal to the rotation axis X is considered. On this cross section, the central shaft portion 32 includes a contour line 32b that forms an arc corresponding to the outer surface 32a, and the ridge portion 33 includes an arc contour line 33b that forms an arc corresponding to the outer surface 33a. The arc contour line 33 b is an arc projecting in a direction away from the central shaft portion 32. Then, the contour line 32 b of the central shaft portion 32 and the arc contour line 33 b of the ridge portion 33 are connected by the contour line 34 b of the connection portion 34. The contour line 34b is an arc curved in the opposite direction to the contour line 32b and the arc contour line 33b. And the curvature radius R of the outline 34b of the connection part 34 is larger than 1/8 of the length L (refer FIG.4 (b)) of the rotation axis X direction of the connector 31. FIG. If the curvature radius R exceeds 1/6 of the length in the direction of the rotation axis X, the possibility that the curvature radius R interferes with the fastening hole 21 of the compressor wheel 7 increases. 1/6 or less of the length in the X direction is desirable.

  Further, as shown in FIG. 5B, a state where the connector 31 is fitted in the tightening hole 21 is considered. At this time, the ridge 33 is fitted into the torque transmission groove 23 with almost no gap. Thus, when the fastening jig 30 is rotated around the rotation axis X (in the direction of the arrow W), the fastening torque is transmitted from the ridge 33 to the torque transmission groove 23. On the other hand, the outer side surface 32a of the central shaft portion 32 and the inner side surface 22a of the main hole portion 22 face each other with a gap F therebetween. The dimension of the gap F corresponds to the dimension of the connecting portion 34 in the rotational radial direction.

  In order to further increase the cross-sectional area of the connector 31, it is conceivable that the gap F as described above is not provided. In other words, it is conceivable that the connector is formed in substantially the same cross-sectional shape as that of the tightening hole 21 so that the connector is inserted into the tightening hole with almost no gap. However, in this case, it is necessary to make the connecting portion between the central shaft portion and the ridge portion a corner or make the roundness of the connecting portion extremely small. In this case, cutting by an end mill becomes impossible, and it becomes necessary to process the connecting portion by, for example, electric discharge machining. As a result, since the workability of the connector is lowered, the configuration in which the connector is formed in substantially the same shape as the fastening hole 21 is contrary to the improvement of workability.

  The effect by the fastening jig | tool 30 provided with the above structure is as follows. The connector 31 of the fastening jig 30 includes a central shaft portion 32 on the rotational axis X, and has a structure in which a protruding strip portion 33 projects from the central shaft portion 32 in the rotational radial direction. Due to the structure in which the central shaft portion 32 exists on the rotation axis X, the cross-sectional area of the connector 31 can be increased, and the strength of the connector 31 against rotation can be improved. Further, since the radius of curvature R of the roundness of the connecting portion 34 between the central shaft portion 32 and the ridge portion 33 is larger than 1/8 of the length L of the connector 31 in the rotation axis X direction, Using a normal end mill having a diameter of / 4 or more, the roundness of the connecting portion 34 can be processed at a time. As a result, since the connector 31 can be cut out by cutting using a normal end mill without using a special tool, the workability of the fastening jig 30 is good. Further, by rounding the connection portion 34, stress concentration on the connection portion 34 when a tightening torque is applied can be reduced.

  The manufacturing method of the rotating body 12 using the fastening jig 30 is as follows. After the collar 18 or the like is attached to the other end of the rotating shaft 14 provided with the turbine impeller 6 at one end, the male screw portion 14a (see FIG. 1) at the other end of the rotating shaft 14 is attached to the compressor impeller 7. The blind screw hole 7b (see FIG. 1) is screwed. Thereafter, the connector 31 of the fastening jig 30 is fitted into the fastening hole 21 (see FIG. 2) of the tip 7a of the compressor impeller 7 (jig fitting process). From that state, a tool such as a hexagon wrench is hung on the tool hook 39 of the fastening jig 30, rotated around the rotation axis X, and a predetermined tightening torque is applied to the compressor wheel 7 to the rotation shaft 14. Screw fastening (screw fastening process). Thereafter, the fastening jig 30 is removed from the front end portion 7 a of the compressor impeller 7.

  According to this manufacturing method, since the compressor impeller 7 is screwed and fastened to the rotary shaft 14 using the fastening jig 30 with improved strength of the connector 31 against rotation, the fastening is achieved even if the tightening torque increases. Screw fastening can be performed without destroying the jig 30 for use.

  Hereinafter, a modification of the fastening jig 30 will be described with reference to FIGS. 6 and 7. Effects similar to those of the fastening jig 30 can also be achieved by modifications of the fastening jigs described below. In addition, about the structure which is the same as that of the jig | tool 30 for fastening in each modification, the same code | symbol is attached | subjected to drawing, and the overlapping description is abbreviate | omitted. 6 (a) to 6 (d) show only a front view (a view seen from the direction of the rotation axis X) of the fastening jig according to the modification, and a side view and a perspective view are omitted, but for each fastening. The lengths of the connector of the jig are all equal to L.

  The fastening jig 50 shown in FIG. 6A is provided with five protruding strips 33 at equal intervals around the central shaft portion 32. In this case, the front end portion 7a of the compressor impeller 7 is provided with a tightening hole 59 including five torque transmission grooves 23 as shown in FIG. As in this example, the number of ridges 33 is not limited to four, and may be five or more, or three or less. By increasing the ridge 33, the tightening torque is distributed in the circumferential direction. However, as shown in FIG. 7A, when the thickness P of the portion between the torque transmission grooves 23 becomes too small, the strength of the portion decreases. Therefore, from the viewpoint of achieving both the dispersion of the tightening torque and the securing of the wall thickness P, the number of the ridge portions 33 can be four or five.

  Further, the central shaft portion is not limited to a cylinder, and a square shaft central shaft portion 62 may be employed as in the fastening jig 60 shown in FIG. According to this shape, the cross-sectional area of the central shaft portion 62 can be increased, and the strength of the connector against rotation can be increased. Further, in the fastening jig 60, the protruding strips 33 are provided at the centers of the four side surfaces of the quadrangular column of the central shaft part 62. However, like the fastening jig 70 shown in FIG. The ridges 33 may be provided at the positions of the four corners of the quadrangular column of the central shaft portion 62.

  Moreover, you may provide the protruding item | line part 83 which extended the width | variety to the rotation circumferential direction with respect to the protruding item | line part 33 like the fastening jig | tool 80 shown by FIG.6 (d). According to the configuration of the fastening jig 80, the strength of the convex portion 83 with respect to the fastening torque is improved. However, in order to form a fastening hole corresponding to the fastening jig 80, a drill alone is not sufficient, and an end mill is required. Therefore, the fastening jig 30 is used rather than the fastening jig 80. However, workability of the tightening hole is good.

  Moreover, you may provide the protruding item | line part 133 which extended the length to the rotation radial direction with respect to the protruding item | line part 33 like the fastening jig | tool 130 shown by FIG.7 (b). FIG. 7B is a cross-sectional view of the ridge 133 and the torque transmission groove 123 of the tightening hole 121 in a cross section orthogonal to the rotation axis X. The ridge 133 is extended in the rotational radial direction by the amount of the rectangular parallelepiped 135 compared to the ridge 33. In other words, in addition to the ridge 33, the ridge 133 further includes a connection plane 135a that connects the connection 34 and the outer surface (cylindrical surface) 33a. The connection plane 135a is a plane corresponding to the side surface of the rectangular parallelepiped 135.

  Correspondingly, the torque transmission groove 123 is also extended by the flat portion 125 a facing the connection flat surface 135 a, and the torque transmission groove 123 is deeper than the torque transmission groove 23. According to this configuration, the contact area with the torque transmission groove 123 is increased by the amount of the connection plane 135a as compared with the ridge portion 33, so that it acts on the ridge portion and the torque transmission groove due to the tightening torque. Reducing stress. However, in order to form the fastening hole 121 corresponding to the fastening jig 130, an end mill is required because the drill alone is not sufficient, so the fastening jig 30 is used rather than the fastening jig 130. The better the workability of the tightening hole.

  As mentioned above, although embodiment of this invention was described, this invention is not restricted to the said embodiment, You may change in the range which does not change the summary described in each claim. For example, each component of the fastening jig according to the embodiment and each modification may be appropriately combined and employed.

1 Supercharger 3 Compressor (centrifugal compressor)
6 Turbine impeller 7 Compressor impeller 7a Tip 12 Rotating body 14 Rotating shaft 21 Tightening hole 23 Torque transmission grooves 30, 50, 60, 70, 80, 130 Fastening jig 31 Connector 32, 62 Central shaft 33, 83, 133 ridge 33a outer side 34 connection 135a connection plane 39 tool hook X rotation axis

Claims (4)

A fastening jig interposed between a compressor impeller of a centrifugal compressor and a tool for screwing and fastening the compressor impeller to a rotary shaft of the centrifugal compressor,
A tool hanging portion on which the tool is hung and rotated;
A connector that extends from the tool hook in the direction of the axis of rotation of the tool hook and is fitted into a tightening hole provided at a tip of the compressor wheel,
The connector is
A central shaft portion extending in the rotational axis direction on the rotational axis and inserted into the center of the fastening hole;
A protruding portion that protrudes from the central shaft portion in the radial direction of the tool hanging portion and extends in the rotational axis direction, and engages with a torque transmission groove provided in the tightening hole, and
The tool hanging portion and the connector are integrally formed by cutting,
A fastening jig in which a radius of curvature of a connection portion between the central shaft portion and the ridge portion is larger than 1/8 of a length of the connector in the rotation axis direction.   The fastening jig according to claim 1, wherein the protruding portion includes an outer surface that forms a cylindrical surface protruding in a direction away from the central shaft portion.   The fastening jig according to claim 2, wherein the protruding portion further includes a connection plane that connects the connection portion and the outer surface. A rotating shaft, a turbine impeller provided at one end of the rotating shaft, and a compressor impeller provided at the other end of the rotating shaft, the rotation built in a turbocharger including the centrifugal compressor A manufacturing method for manufacturing a body,
The center shaft portion of the fastening jig according to any one of claims 1 to 3 is inserted into the center of the tightening hole and the protruding portion is engaged with the torque transmission groove, A jig fitting step for fitting a connector into the fastening hole of the compressor wheel,
A method of manufacturing a rotating body, comprising: a screwing and fastening step in which a tool is put on the tool hanging portion of the fastening jig and rotated around the rotation axis, and the compressor impeller is screwed and fastened to the rotation shaft. .

Images