JP7280724B2 - Gear shaft and gear shaft manufacturing method - Google Patents

Description

The present invention provides a gear shaft including a shaft body having a cylindrical portion, a gear portion provided on the outer peripheral portion of the shaft body, and a lid member disposed in the inner space of the cylindrical portion, and , to a method for manufacturing the gear shaft.

As such a gear shaft, for example, one described in Japanese Unexamined Patent Application Publication No. 2013-204754 (Patent Document 1) is known. In the following description of the background art, the symbols or names in parentheses are the symbols or names in the prior art documents. The cylindrical portion of the gear shaft (countershaft 40) described in Patent Document 1 includes an opening (opening 401) that opens toward the first side in the axial direction at the end portion on the first side in the axial direction of the shaft main body, and a contact inner peripheral surface portion surrounding the inner space (hollow portion 400) of the cylindrical portion. A chamfered portion (chamfered portion 401t) in the shape of a truncated cone that is inclined radially outward toward the first side in the axial direction is formed in the opening. The contact inner peripheral surface portion is the inner peripheral surface portion with which the outer edge portion of the lid member (plug 50) contacts, and the inner space of the cylindrical portion is used as a space for oil to flow, and the flow of oil is restricted by the lid member. .

JP 2013-204754 A

When manufacturing the gear shaft as described above, if the gear shaft is formed in a cylindrical shape and has an internal space, the shaft main body is deformed by a load from the outside in the radial direction when forming the gear portion (drive pinion gear 28c). there's a possibility that. Therefore, when manufacturing a gear shaft, first, a chamfered portion is formed without forming a large internal space, and then the gear portion is formed with the chamfered portion being used as a reference for centering. Machining may be performed in the order of cutting so as to form an internal space.

As described above, when the chamfered portion and the contact inner peripheral surface portion surrounding the internal space are processed in separate processing steps, the boundary portion between them tends to be in a state where they are not smoothly connected. Therefore, when the lid member is inserted from the opening and installed in the internal space, the lid member is shaved by the corners of the boundary portion between the chamfered portion and the contact inner peripheral surface portion, and unnecessary protrusions such as burrs and cut pieces are formed on the lid. It may remain on the material. If such unnecessary projections remaining on the cover member come off from the cover member during use of the gear shaft, they may act as foreign matter and adversely affect the apparatus.

Therefore, after forming the gear portion based on the chamfered portion, an internal space is formed in the shaft body, and the chamfered portion is cut so as to be continuous with the formation of the contact inner peripheral surface portion surrounding this internal space. By forming such a chamfered portion, it is possible to smoothly connect the boundary portion between the contact inner peripheral surface portion and the newly formed chamfered portion. However, when forming a new chamfered portion in this way, the position of the chamfered portion, which serves as a reference when machining each part, changes before and after cutting the chamfered portion. may decline.

Therefore, it is desired to realize a gear shaft that maintains machining accuracy of the gear shaft and prevents unnecessary projections from occurring on the lid member when the lid member is installed, and a method of manufacturing such a gear shaft.

In view of the above, the characteristic configuration of the gear shaft includes a shaft body having a cylindrical portion, a gear portion provided on the outer peripheral portion of the shaft body, and a lid member disposed in the inner space of the cylindrical portion. , and
With one axial side of the shaft main body as the first axial side, the tubular portion is an opening that opens toward the first axial side at the end of the shaft main body on the first axial side. and a tubular inner peripheral surface surrounding the internal space of the tubular portion, wherein the tubular inner peripheral surface is a contact inner peripheral surface portion that is an inner peripheral surface portion with which the outer edge portion of the lid member contacts; an enlarged diameter inner peripheral surface portion which is an inner peripheral surface portion having a diameter larger than that of the contact inner peripheral surface portion; The enlarged diameter inner peripheral surface portion is disposed between the chamfered portion and the contact inner peripheral surface portion in the axial direction, and the boundary between the contact inner peripheral surface portion and the enlarged diameter inner peripheral surface portion is formed. A radial stepped portion is formed in the portion, and the radially inner edge of the stepped portion is formed in an annular shape having an arc-shaped cross section that protrudes radially inward.

According to this characteristic configuration, the radially inner edge of the stepped portion is formed in an annular shape having an arc-shaped cross section, so that the contact inner peripheral surface portion and the contact inner peripheral surface portion are axially arranged in the first axial direction with respect to the contact inner peripheral surface portion. It is possible to smoothly connect the boundary portion with the enlarged diameter inner peripheral surface portion adjacent to the side. Therefore, when the lid member is inserted from the opening and installed in the internal space, it is possible to avoid scraping the lid member by the stepped portion at the boundary between the contact inner peripheral surface portion and the enlarged diameter inner peripheral surface portion, and the lid member is prevented from being scraped. It is possible to reduce the possibility of generating unnecessary protrusions such as burrs and cut pieces.

Further, according to this configuration, since the enlarged-diameter inner peripheral surface portion is formed between the chamfered portion and the contact inner peripheral surface portion in the axial direction, the diameter of the radially inner edge of the chamfered portion is made larger than that of the lid member. can also be made larger. Therefore, when the lid member is inserted through the opening and installed in the internal space, it is possible to prevent the lid member from being scraped by the radially inner edge of the chamfered portion. Therefore, it is possible to eliminate the need to process the radially inner edge of the chamfered portion into a smooth shape, and to avoid performing additional processing on the chamfered portion. As a result, the same chamfered portion can be used as a reference surface through a plurality of machining steps, so machining accuracy can be maintained.
As described above, according to the present configuration, it is possible to provide a gear shaft in which unnecessary protrusions are less likely to occur on the cover member when the cover member is installed while maintaining the machining accuracy of the gear shaft.

In view of the above, the characteristic configuration of the gear shaft manufacturing method includes a shaft body having a cylindrical portion, a gear portion provided on the outer peripheral portion of the shaft body, and a gear portion disposed in the inner space of the cylindrical portion. and a lid member, wherein one side of the shaft main body in the axial direction is defined as the first side in the axial direction, and the tubular portion is positioned at the first axial side at the end of the shaft main body on the first side in the axial direction. and a cylindrical inner peripheral surface surrounding the inner space of the cylindrical portion, comprising:
a chamfer forming step of forming a chamfered portion in the shape of a truncated cone that is inclined radially outward toward the first side in the axial direction in the opening;
After the chamfer forming step, a gear forming step of forming the gear portion in a state where the gear portion is positioned with reference to the chamfered portion;
After the gear forming step, the cylindrical inner peripheral surface includes a contact inner peripheral surface portion, which is an inner peripheral surface portion in contact with the outer edge portion of the lid member, and an enlarged diameter inner peripheral surface portion having a larger diameter than the contact inner peripheral surface portion. an inner periphery forming step of forming an inner peripheral surface portion;
a lid arranging step of arranging the lid member on the contact inner peripheral surface,
In the inner circumference forming step, the enlarged diameter inner peripheral surface portion is formed between the chamfered portion and the contact inner peripheral surface portion in the axial direction, and is a boundary between the contact inner peripheral surface portion and the enlarged diameter inner peripheral surface portion. A radially stepped portion is formed in the contact inner peripheral surface portion, and the radially inner edge of the stepped portion forms an annular ring having an arcuate cross section projecting radially inwardly. The point is that the step portion and the diameter-enlarged inner peripheral surface portion are formed by continuous cutting.

According to this characteristic configuration, in the inner periphery forming step, the radially inner edge of the stepped portion is formed in an annular shape having an arc-shaped cross section, so that the contact inner peripheral surface portion and the contact inner peripheral surface portion On the other hand, the boundary portion with the enlarged diameter inner peripheral surface portion adjacent to the axial direction first side can be smoothly connected. Therefore, when the lid member is inserted through the opening and installed in the internal space in the lid placement step, it is possible to avoid scraping the lid member by the stepped portion at the boundary between the contact inner peripheral surface portion and the diameter-enlarging inner peripheral surface portion. , the possibility that unnecessary projections such as burrs and cut pieces are formed on the cover member can be reduced.

Further, according to this configuration, in the inner circumference forming step, the enlarged diameter inner peripheral surface is formed between the chamfered portion and the contact inner peripheral surface portion in the axial direction. can be made larger than the diameter of the lid member. Therefore, when the lid member is inserted through the opening and installed in the internal space, it is possible to prevent the lid member from being scraped by the radially inner edge of the chamfered portion. Therefore, it is possible to eliminate the need to process the radially inner edge of the chamfered portion into a smooth shape, and to avoid performing additional processing on the chamfered portion. As a result, the same chamfered portion can be used as a reference surface through a plurality of machining steps, so machining accuracy can be maintained.
As described above, according to the present configuration, it is possible to provide a gear shaft manufacturing method in which unnecessary protrusions are less likely to occur on the cover member when the cover member is installed while maintaining the machining accuracy of the gear shaft.

1 is an axial cross-sectional view of a vehicle drive transmission device according to an embodiment; FIG. 2 is a cross-sectional view perpendicular to the axial direction showing the essential parts of the vehicle drive transmission device according to the embodiment; Sectional view along the axial direction of the gear shaft according to the embodiment Cross-sectional view of the axial direction first side end portion of the gear shaft according to the embodiment Sectional drawing which shows the principal part of the inner peripheral surface part of the cylindrical part which concerns on embodiment FIG. 4 shows a manufacturing process of the gear shaft according to the embodiment; FIG. 6 is a cross-sectional view showing the end portion of the gear shaft on the first side in the axial direction in the first preparation step according to the embodiment; FIG. 5 is a cross-sectional view showing the end portion of the gear shaft on the first side in the axial direction in the chamfer formation step according to the embodiment; FIG. 4 is a cross-sectional view showing the end portion of the gear shaft on the first side in the axial direction in the gear forming process according to the embodiment; FIG. 6 is a cross-sectional view showing the end portion of the gear shaft on the first side in the axial direction in the second preparation step according to the embodiment; FIG. 5 is a cross-sectional view showing the end portion of the gear shaft on the first side in the axial direction in the inner periphery forming step according to the embodiment;

1. Embodiment Hereinafter, a gear shaft and a method for manufacturing the gear shaft according to the embodiment will be described with reference to the drawings. Here, a case where the gear shaft 7 according to the present embodiment is provided in the vehicle drive transmission device 100 will be described. The vehicle drive transmission device 100 is mounted, for example, on a hybrid vehicle that uses an internal combustion engine and a rotating electrical machine as driving force sources for a plurality of wheels, or an electric vehicle that uses a rotating electrical machine as a driving force source for a plurality of wheels.

As shown in FIG. 1, a vehicle drive transmission device 100 transmits driving force between a driving force source and a pair of wheels. In this embodiment, the rotating electric machine MG functions as a driving force source. In this specification, the term "rotary electric machine" is used as a concept including motors (electric motors), generators (generators), and motors/generators that function as both motors and generators as necessary. .

A vehicle drive transmission device 100 includes a gear mechanism 1 provided in a power transmission path that connects a driving force source and a pair of wheels, and a case 2 that houses the gear mechanism 1 .

In this embodiment, the gear mechanism 1 includes an input member 3 drivingly connected to a driving force source, a counter gear mechanism 4, and a differential gear for distributing the driving force transmitted from the driving force source to a pair of wheels. a device 5; The input member 3 is arranged on the first axis A1 as its rotation axis. In this embodiment, the rotary electric machine MG drivingly connected to the input member 3 is also arranged on the first axis A1. The counter gear mechanism 4 is arranged on the second axis A2 as its rotation axis, and the differential gear device 5 is arranged on the third axis A3 as its rotation axis. The first axis A1, the second axis A2, and the third axis A3 are virtual axes different from each other, and are arranged parallel to each other.

In the following description, the direction parallel to the axes A1 to A3 is defined as the "axial direction L" of the vehicle drive transmission device 100. As shown in FIG. In the axial direction L, the side on which the rotary electric machine MG is arranged with respect to the input member 3 is defined as "first axial side L1", and the opposite side is defined as "second axial side L2". Further, a direction orthogonal to each of the first axis A1, the second axis A2, and the third axis A3 is defined as a "radial direction R" with respect to each axis. In addition, when it is not necessary to distinguish which axis should be used as a reference, or when it is clear which axis should be used as a reference, it may simply be described as “radial direction R”.

Here, in the present application, the term “driving connection” refers to a state in which two rotating elements are connected so as to be able to transmit a driving force, and the two rotating elements are connected so as to rotate integrally. It includes a state in which two rotating elements are connected so as to be able to transmit driving force via one or more transmission members. Such transmission members include various members that transmit rotation at the same speed or at different speeds, such as shafts, gear mechanisms, belts, and chains. The transmission member may include an engagement device for selectively transmitting rotation and driving force, such as a friction engagement device and a mesh type engagement device. However, in the differential gear device 5, when each rotating element is referred to as "driving connection", it refers to a state in which three or more rotating elements included in the device are drivingly connected to each other without interposing other rotating elements. shall be

The rotary electric machine MG includes a stator St and a rotor Ro. The stator St has a stator core Stc supported by the case 2 and a coil C wound around the stator core Stc. The rotor Ro has a rotor core Roc rotatable with respect to the stator core Stc, and permanent magnets M arranged within the rotor core Roc. In this embodiment, the rotor core Roc is arranged inside in the radial direction R with respect to the stator core Stc. A rotor shaft Ros is connected to the inner peripheral surface of the rotor core Roc.

The rotor shaft Ros is formed in a cylindrical shape extending along the axial direction L. As shown in FIG. The rotor shaft Ros rotates integrally with the rotor Ro about the first axis A1. The rotor shaft Ros is connected to the input member 3, and the rotor shaft Ros and the input member 3 rotate integrally.

In this embodiment, the case 2 has a peripheral wall portion 21 that surrounds the outer side of the rotary electric machine MG, the input member 3 , the counter gear mechanism 4 , and the differential gear device 5 in the radial direction R. Moreover, in this embodiment, the case 2 has the first side wall portion 22 and the second side wall portion 23 extending along the radial direction R. As shown in FIG. The first side wall portion 22 is arranged on the second side L2 in the axial direction with respect to the input member 3 and the counter gear mechanism 4 . The second side wall portion 23 is arranged in the axial direction L between the input member 3 and the counter gear mechanism 4 and the rotary electric machine MG.

Further, the case 2 has bearing support portions 24 that support the bearings of the respective shafts of the gear mechanism 1 . In this embodiment, the bearing support portion 24 includes a first bearing support portion 24A that supports the first input bearing 91 and the first counter bearing 93, and a second bearing that supports the second input bearing 92 and the second counter bearing 94. and a support portion 24B. The first bearing support portion 24A is formed on the first side wall portion 22 and the second bearing support portion 24B is formed on the second side wall portion 23 . The first input bearing 91 and the second input bearing 92 are bearings that rotatably support the input member 3 . The first counter bearing 93 and the second counter bearing 94 are bearings that rotatably support the counter gear mechanism 4 .

The input member 3 is an input element of the gear mechanism 1 . The input member 3 has an input shaft 31 and an input gear 32 . A gear shaft 7 is configured by the input shaft 31, the input gear 32, and the like. In this example, the gear shaft 7 is a single member, and the gear shaft 7 in this example does not include, for example, a separately formed parking gear 33 which will be described later.

The input shaft 31 is a shaft member extending along the axial direction L. As shown in FIG. This input shaft 31 corresponds to the shaft body 72 of the gear shaft 7 . In this embodiment, the end of the input shaft 31 on the first axial side L1 is connected to the end of the rotor shaft Ros on the second axial side L2. In the illustrated example, the end portion of the input shaft 31 on the first side L1 in the axial direction is aligned with the end on the second side L2 in the axial direction of the rotor shaft Ros so that the input shaft 31 is positioned inside the rotor shaft Ros in the radial direction R. and the ends are connected by spline engagement. For this reason, a large number of grooves (spline grooves) for spline engagement are formed on the outer peripheral surface of the end of the input shaft 31 on the first side L1 in the axial direction. In this embodiment, as will be described later, this spline groove forms a first gear portion 73 as a gear portion of the gear shaft 7 .

The input shaft 31 is rotatably supported by the case 2 via a first input bearing 91 and a second input bearing 92 . In the present embodiment, the end portion of the input shaft 31 on the axial second side L2 is rotatably supported by the first bearing support portion 24A of the case 2 via the first input bearing 91 . Further, a portion of the input shaft 31 on the first side L1 in the axial direction from the central portion in the axial direction L and on the second side L2 in the axial direction from the connection portion with the rotor shaft Ros is a second input bearing. It is rotatably supported by the second bearing support portion 24B of the case 2 via 92 .

The input gear 32 is a gear that transmits the driving force from the driving force source to the counter gear mechanism 4 . The input gear 32 is connected to the input shaft 31 . In this embodiment, the input gear 32 is formed integrally with the input shaft 31 . Further, in this embodiment, the input gear 32 is arranged between the first input bearing 91 and the second input bearing 92 . In the illustrated example, the input gear 32 is arranged adjacent to the first input bearing 91 on the axial first side L1.

In this embodiment, the input shaft 31 is provided with a parking gear 33 . The parking gear 33 is configured to be switchable between a non-rotatable locked state and a rotatable unlocked state by a parking lock mechanism (not shown). Parking gear 33 is connected to input shaft 31 so as to rotate integrally with input shaft 31 . In this embodiment, the parking gear 33 is connected to the input shaft 31 by spline engagement. For this reason, a large number of grooves (spline grooves) for spline engagement are formed on the outer peripheral surface of the portion of the input shaft 31 corresponding to the parking gear 33 . In this embodiment, this spline groove serves as the second gear portion 74, as will be described later.

The counter gear mechanism 4 is arranged between the input member 3 and the differential gear device 5 in the power transmission path. The counter gear mechanism 4 has a counter shaft 41 , a first counter gear 42 and a second counter gear 43 .

The counter shaft 41 is a shaft member extending along the axial direction L. As shown in FIG. The counter shaft 41 is rotatably supported by the case 2 via a first counter bearing 93 and a second counter bearing 94 . In this embodiment, the end portion of the counter shaft 41 on the second side L2 in the axial direction is rotatably supported by the first bearing support portion 24A of the case 2 via the first counter bearing 93. The end of the direction first side L1 is rotatably supported by the second bearing support portion 24B of the case 2 via the second counter bearing 94 .

The first counter gear 42 is an input element of the counter gear mechanism 4 . The first counter gear 42 meshes with the input gear 32 of the input member 3 . A second counter gear 43 is an output element of the counter gear mechanism 4 . In this embodiment, the second counter gear 43 is formed with a smaller diameter than the first counter gear 42 .

The differential gear device 5 distributes the driving force transmitted from the driving force source side to the pair of wheels. In this embodiment, the differential gear device 5 distributes the driving force from the rotary electric machine MG transmitted through the input member 3 and the counter gear mechanism 4 to the drive shafts DS drivingly connected to the respective wheels. do. The differential gear device 5 has a differential input gear 51 , a differential case 52 , a pinion shaft 53 , a pair of pinion gears 54 and a pair of side gears 55 . In this embodiment, both the pair of pinion gears 54 and the pair of side gears 55 are bevel gears.

A differential input gear 51 is an input element of the differential gear device 5 . The differential input gear 51 meshes with the second counter gear 43 of the counter gear mechanism 4 . The differential input gear 51 rotates around the third axis A3. The differential input gear 51 is connected to the differential case 52 so as to rotate together with the differential case 52 .

The differential case 52 rotates integrally with the differential input gear 51 around the third axis A3. The end of the differential case 52 on the axial second side L2 is rotatably supported with respect to the case 2 via a first differential bearing 95 . An end portion of the differential case 52 on the first side L1 in the axial direction is rotatably supported with respect to the case 2 via a second differential bearing 96 . The differential case 52 is a hollow member. A pinion shaft 53 , a pair of pinion gears 54 , and a pair of side gears 55 are housed inside the differential case 52 . A pair of side gears 55 are each connected to the drive shaft DS.

As shown in FIG. 2, inside the case 2, there are a first storage portion 10A in which the oil F is stored, and a second storage portion 10B arranged above the first storage portion 10A and in which the oil F is stored. and is provided.

In this embodiment, the first reservoir 10A is a space surrounded by the inner surface of the case 2 in the lower portion of the case 2 . An amount of oil F that can be scraped up by the differential input gear 51 of the differential gear device 5 is stored in the first reservoir 10A. That is, the oil level of the oil F stored in the first reservoir 10A is set above the lower end of the differential input gear 51 while the differential gear device 5 is operating (while the vehicle is running).

The second storage part 10B functions as a catch tank for lowering the oil level of the oil F stored in the first storage part 10A while securing a sufficient amount of the oil F in the case 2 . That is, the oil level height of the oil F stored in the first storage portion 10A becomes lower as the amount of the oil F stored in the second storage portion 10B increases. In this embodiment, the second reservoir 10B is arranged above the first axis A1, the second axis A2, and the third axis A3.

As shown in FIG. 1, the second reservoir 10B is configured using a reservoir-constituting member 6. As shown in FIG. In this embodiment, the storage portion forming member 6 has a connecting portion 62 that connects the connection oil passage 25A formed in the oil passage forming portion 25 of the case 2 and the second storage portion 10B. The oil passage formation portion 25 is a portion of the case 2 in which a connection oil passage 25A through which the oil F flows is formed.

In this embodiment, a first supply hole 63 and a second supply hole 64 are formed in the storage portion forming member 6 . The first supply hole 63 is arranged at a position overlapping the input gear 32 of the input member 3 when viewed in the vertical direction. The second supply hole 64 is arranged at a position overlapping the parking gear 33 when viewed in the vertical direction. As a result, the oil F that has flowed out of the second reservoir 10B drops through the first supply hole 63 and is supplied to the input gear 32 . Also, the oil F that has flowed out of the second storage portion 10B drops through the second supply hole 64 and is supplied to the parking gear 33 .

In the present embodiment, regarding the arrangement of two elements, "overlapping in a particular direction view" means that when a virtual straight line parallel to the line-of-sight direction is moved in each direction orthogonal to the virtual straight line, It means that there is at least a part of the area where the virtual straight line intersects both of the two elements.

The oil F is circulated inside the case 2 by an oil circulation mechanism. In this embodiment, the differential input gear 51 of the differential gear device 5 functions as an oil circulation mechanism. That is, when the differential input gear 51 rotates, the oil F stored in the first storage portion 10A is scraped up by the differential input gear 51 (see FIG. 2). A portion of the oil F thus raked up is supplied to the second reservoir 10B as indicated by the dashed line in FIG. Specifically, the oil F stored in the first reservoir 10A is raked up by the differential input gear 51, and part of the oil F thus raked up reaches above the second reservoir 10B. The oil F is supplied to the second reservoir 10B by dropping from the .

Moreover, as shown in FIG. 1, in this embodiment, a hydraulic pump 8 is provided as another oil circulation mechanism. The hydraulic pump 8 is a mechanical hydraulic pump driven by driving force transmitted through a power transmission path. In this embodiment, the hydraulic pump 8 is connected to a pump drive shaft 81 that is connected to rotate integrally with the counter shaft 41 of the counter gear mechanism 4, and to the pump drive shaft 81 that rotates integrally. and a pump rotor 82 .

The hydraulic pump 8 pumps up the oil F stored in the first reservoir 10A and supplies the pumped-up oil F to each part in the case 2 . In this embodiment, part of the oil F discharged from the hydraulic pump 8 passes through an oil passage formed to penetrate the pump drive shaft 81 in the axial direction L, and then penetrates the counter shaft 41 in the axial direction L. It flows to the counter shaft oil passage 41A formed to do so. After that, the oil F that has passed through the counter shaft oil passage 41A flows out from the opening at the end of the counter shaft 41 on the first side L1 in the axial direction. The oil F flowing out from the counter shaft oil passage 41A lubricates the second counter bearing 94, the differential gear device 5, and the like.

On the other hand, as shown in FIGS. 1 and 3, another part of the oil F discharged from the hydraulic pump 8 flows into the side wall inner oil passage 22A formed inside the first side wall portion 22 of the case 2. . The oil F that has flowed into the side wall inner oil passage 22A flows into the case 2 through each of the branch oil passage 22B and the connection oil passage 25A branched from the side wall inner oil passage 22A.

The oil F that has passed through the branched oil passage 22B flows into the input shaft oil passage 31A formed so as to penetrate the input shaft 31 of the input member 3 in the axial direction L. The oil F that has flowed to the input shaft oil passage 31A flows out from the oil discharge oil passage 31B formed in the input shaft 31 . The oil F discharged from the oil discharge oil passage 31B lubricates the second input bearing 92 and the like. The oil F that has passed through the connection oil passage 25A is supplied to the second storage portion 10B via the connection portion 62 .

Next, the gear shaft 7 will be described with reference to FIGS. 3 and 4. FIG. In the following description, the input shaft 31 will be referred to as a shaft body 72 . As shown in FIG. 3, the gear shaft 7 includes a shaft body 72 having a tubular portion 71, a first gear portion 73 and a second gear portion 74 provided on the outer peripheral portion of the shaft body 72, and an input gear 32. and a lid member 75 such as a plug arranged in the internal space S of the tubular portion 71 . Here, at least one of the first gear portion 73, the second gear portion 74, and the input gear 32 corresponds to the "gear portion".

In this embodiment, both the first gear portion 73 and the second gear portion 74 are gear portions having a large number of grooves (spline grooves) formed along the axial direction L for spline engagement. These first gear portion 73 and second gear portion 74 are integrally formed with the input shaft 31 . As shown in FIG. 1, the first gear portion 73 is inserted into the end portion of the rotor shaft Ros on the second axial side L2, and the inner peripheral surface of the end portion of the rotor shaft Ros on the second axial side L2. engages with spline grooves formed in the The second gear portion 74 is inserted into the parking gear 33 and engages with spline grooves formed on the inner peripheral surface of the parking gear 33 . As shown in FIG. 3, in the present embodiment, the first gear portion 73 is provided on the first side L1 in the axial direction from the central portion of the shaft body 72 in the axial direction L. As shown in FIG. More specifically, the first gear portion 73 is provided at the end portion of the shaft main body 72 on the first side L1 in the axial direction. The input gear 32 is provided on the second side L2 in the axial direction from the central portion in the axial direction L of the shaft body 72 . The second gear portion 74 is provided between the first gear portion 73 and the input gear 32 in the axial direction L. As shown in FIG.

The cylindrical portion 71 includes a first opening 76 that opens toward the first axial side L1 at the end portion of the shaft main body 72 on the first axial side L1. In this embodiment, in addition to the first opening 76, the tubular portion 71 has a second opening 77 that opens toward the second axial side L2 at the end of the shaft main body 72 on the second axial side L2. It has The cylindrical portion 71 has an internal space S passing through the shaft body 72 from the first opening 76 to the second opening 77 . Thus, the shaft main body 72 according to the present embodiment is formed in a cylindrical shape as a whole and has an internal space S formed so as to be continuous over the entire area in the axial direction L. As shown in FIG. That is, in this embodiment, the entire shaft body 72 is the cylindrical portion 71 . The first opening 76 corresponds to the "opening".

The first opening 76 is formed with a chamfered portion F2 in the shape of a truncated cone that is inclined toward the radially outer side R1 toward the first side L1 in the axial direction. In this embodiment, in addition to the chamfered portion F2, the first opening portion 76 is formed with a relief surface portion F1 in the shape of a truncated cone that is inclined toward the radially outer side R1 toward the first axial side L1. there is Note that the truncated cone surface shape is the shape of the side peripheral surface of the truncated cone, and is a shape in which the diameter increases (or decreases) toward the first side L1 in the axial direction. The chamfered portion F2 is used as a reference surface when the gear shaft 7 is machined. In the illustrated example, the chamfered portion F2 is a surface along a direction inclined at 45° with respect to the axial direction L. As shown in FIG. The relief surface portion F1 is formed on the axial first side L1 and radially outward R1 from the chamfered portion F2. The angle of inclination of the relief surface portion F1 with respect to the axial direction L is greater than the angle of inclination with respect to the axial direction L of the chamfered portion F2. Even if the end surface E of the gear shaft 7 on the first side L1 in the axial direction is damaged, the relief surface portion F1 does not affect the chamfered portion F2, which serves as a reference surface for processing. is established for

The relief surface portion F1 is formed along the direction toward the radially inner side R2 from the end surface E of the shaft body 72 toward the axial second side L2. The chamfered portion F2 is formed along the direction toward the radially inner side R2 from the end portion of the relief surface portion F1 on the second axial side L2 toward the second axial side L2. That is, in this example, the relief surface portion F1 and the chamfered portion F2 are formed in a continuous state. It should be noted that the second opening 77 is also formed with a relief surface portion F1 and a chamfered portion F2 in the same manner as the first opening portion .

The tubular portion 71 has a tubular inner peripheral surface F0 surrounding the internal space S of the tubular portion 71 . The cylindrical inner peripheral surface F0 includes a contact inner peripheral surface portion F5 that is an inner peripheral surface portion with which the outer edge portion of the lid member 75 contacts, an enlarged diameter inner peripheral surface portion F3 that is an inner peripheral surface portion having a larger diameter than the contact inner peripheral surface portion F5, It has The enlarged diameter inner peripheral surface portion F3 is arranged between the chamfered portion F2 in the axial direction L and the contact inner peripheral surface portion F5. A stepped portion F4 extending in the radial direction R is formed at the boundary portion between the contact inner peripheral surface portion F5 and the enlarged diameter inner peripheral surface portion F3. That is, the cylindrical inner peripheral surface F0 includes an enlarged diameter inner peripheral surface portion F3, a stepped portion F4, and a contact inner peripheral surface portion F5.

The contact inner peripheral surface portion F5 and the enlarged diameter inner peripheral surface portion F3 are formed parallel to the axial direction L. As shown in FIG. The stepped portion F4 is a stepped portion formed at the boundary portion between the contact inner peripheral surface portion F5 and the enlarged diameter inner peripheral surface portion F3 due to the difference in diameter between them. Therefore, the stepped portion F4 has a stepped surface facing the first side L1 in the axial direction. In this embodiment, the stepped portion F4 has a stepped surface that is inclined toward the radially outer side R1 toward the first axial side L1. An edge portion F41 on the radially inner side R2 of the stepped portion F4 is formed in an annular shape having an arc-shaped cross section that protrudes toward the radially inner side R2. Furthermore, in the present embodiment, the portion of the edge portion F41 connected to the contact inner peripheral surface portion F5 is formed in a shape in which the tangent line is parallel to the axial direction L and has the same diameter as the contact inner peripheral surface portion F5. It's becoming As a result, the step portion F4 and the contact inner peripheral surface portion F5 are smoothly connected to each other. In the present embodiment, the term "smoothly connected shape" refers to a shape in which surfaces are continuously formed without angular portions on the surface. Also, the "arcuate cross-section" is not strictly required to be an arc, but is intended to include all cross-sections having a shape close to an arc. Also, the diameter of the arc in the arc-shaped cross section can be set arbitrarily. In the present embodiment, the entire portion of the stepped surface of the stepped portion F4 other than the edge portion F41 of the radially inner side R2 has a truncated cone surface shape that is inclined toward the radially outer side R1 toward the first axial side L1. is formed in

The enlarged diameter inner peripheral surface portion F3 is formed at a position adjacent to the axial second side L2 of the end portion of the chamfered portion F2 on the axial second side L2. The stepped portion F4 is formed at a position adjacent to the axial second side L2 of the end portion of the enlarged diameter inner peripheral surface portion F3 on the axial second side L2. The contact inner peripheral surface portion F5 is formed at a position adjacent to the axial second side L2 of the end portion of the stepped portion F4 on the axial second side L2. That is, the enlarged diameter inner peripheral surface portion F3, the stepped portion F4, and the contact inner peripheral surface portion F5 are formed in a continuous state. In this embodiment, part of the enlarged diameter inner peripheral surface portion F3, the stepped portion F4, and the contact inner peripheral surface portion F5 is formed in a region overlapping the first gear portion 73 when viewed in the radial direction. In other words, the first gear portion 73 is arranged in a region of the shaft body 72 that partially overlaps the enlarged diameter inner peripheral surface portion F3, the stepped portion F4, and the contact inner peripheral surface portion F5 when viewed in the radial direction.

The chamfered portion F2 and the relief surface portion F1 of the first opening portion 76 are also formed so as to surround the internal space S of the tubular portion 71 . It is an inner peripheral surface that surrounds the space. Therefore, the inner peripheral surface surrounding the inner space of the cylindrical portion 71 is composed of a relief surface portion F1, a chamfered portion F2, an enlarged diameter inner peripheral surface portion F3, and a stepped portion from the first axial side L1 toward the second axial side L2. F4 and the contact inner peripheral surface portion F5 are formed continuously in the described order. However, in the present embodiment, the cylindrical inner peripheral surface F0 includes the enlarged diameter inner peripheral surface portion F3, the stepped portion F4, and the contact inner peripheral surface portion F5 as described above, but the relief surface portion F1 and the chamfered portion F2 are not included. defined as not including

The shaft body 72 has an oil discharge portion 10 penetrating in the radial direction R. As shown in FIG. The oil discharge portion 10 is formed between the second opening 77 and the lid member 75 in the axial direction L of the shaft body 72 . In this embodiment, the lid member 75 is arranged so that the entire outer peripheral edge portion thereof is in contact with the contact inner peripheral surface portion F5. Further, in this example, the lid member 75 does not have a through-hole, a groove portion, or the like that penetrates in the axial direction L. As shown in FIG. Therefore, the lid member 75 functions to restrict the flow of the oil F in the internal space S from the axial second side L2 to the axial first side L1 with respect to the lid member 75 . In this embodiment, the lid member 75 is arranged at a position overlapping the first gear portion 73 when viewed in the radial direction.

Next, a method for manufacturing the gear shaft 7 will be described. In particular, a method of manufacturing the end portion of the gear shaft 7 on the first side L1 in the axial direction will be described. As shown in FIG. 6, when manufacturing the gear shaft 7, a first preparation step S1, a chamfer formation step S2, a gear formation step S3, a second preparation step S4, an inner circumference formation step S5, A lid placement step S6 is performed. Each of these steps is performed in the order described. That is, the chamfer formation step S2 is performed after the first preparation step S1. The gear formation step S3 is performed after the chamfer formation step S2. The second preparation step S4 is performed after the gear formation step S3. The inner periphery forming step S5 is performed after the second preparatory step S4. The lid placement step S6 is performed after the inner circumference forming step S5.

In the first preparation step S1, as shown in FIG. 7, a portion of the shaft main body 72 in the axial direction L is extended from the end portion of the shaft main body 72 on the first axial side L1 toward the second axial side L2. This is the step of forming the first machined inner peripheral surface portion F6 in the defined region D1. The first processed inner peripheral surface portion F6 is an inner peripheral surface portion having a smaller diameter than the contact inner peripheral surface portion F5 (see FIG. 4) to be formed later. In this embodiment, the gear shaft 7 (specifically, the material forming the gear shaft 7) is rotated about its axis while the end portion of the gear shaft 7 (specifically, the material forming the gear shaft 7) on the second side L2 in the axial direction is held by a chuck (not shown). Then, a cutting tool such as a drill is pressed from the end portion of the gear shaft 7 on the first side L1 in the axial direction to form a hole, thereby forming the first machined inner peripheral surface portion F6.

An end portion of the defined region D1 on the first axial side L1 is set to an end surface E of the gear shaft 7 on the first axial side L1. Further, the end portion of the specified region D1 on the second axial side L2 is set within the range in the axial direction L of the gear forming region D2. In the present embodiment, the length of overlap between the specified region D1 and the gear forming region D2 in the axial direction L is set to ⅓ or less of the length of the entire gear forming region D2 in the axial direction L. is set. By setting the defined region D1 in this manner, the end portion of the first machined inner peripheral surface portion F6 on the second axial side L2 in the axial direction L is the gear forming region D2 where the first gear portion 73 is formed. (See FIGS. 4 and 7), a first processed inner peripheral surface portion F6 is formed.

The chamfer forming step S2 is a step of forming a chamfered portion F2 in the first opening portion 76, as shown in FIG. In this embodiment, the chamfered portion F2 and the relief surface portion F1 are formed in the chamfered portion forming step S2. In the chamfer formation step S2, the gear shaft 7 is rotated while holding the end portion of the gear shaft 7 on the second side L2 in the axial direction, and a part of the first processed inner peripheral surface portion F6 is cut by a cutting tool 11 such as a cutting tool. Thus, the relief surface portion F1 and the chamfered portion F2 are formed by a series of cutting processes. At this time, the chamfered portion F2 is formed so as to be continuous with the first processed inner peripheral surface portion F6. Further, in the present embodiment, in the chamfer formation step S2, the second opening 77 is also processed in the same manner as the first opening 76 to form the relief surface portion F1 and the chamfer portion F2 in the second opening portion 77. do.

As shown in FIG. 9, the gear forming step S3 is a step of forming the first gear portion 73 with the chamfered portion F2 positioned as a reference. In the gear forming step S3, first, the outer surface of the centering jig 12 is aligned with the chamfered portion of the first opening 76 while the end of the gear shaft 7 on the second side L2 in the axial direction is held by a chuck (not shown). Centering is performed by inserting the centering jig 12 into the gear shaft 7 so as to contact F2. At this time, the centering jig 12 may be brought into contact with the chamfered portion F2 of the second opening 77 to perform the centering. In the gear forming step S3, the first gear portion 73 is formed with the gear shaft 7 thus centered. In this example, the first gear portion 73 is formed by a rolling process in which the first gear portion 73 is formed by pressing the rolling die 13 against the outer peripheral portion of the gear shaft 7 while rotating the gear shaft 7 . Although illustration is omitted, in the present embodiment, the formation of the second gear portion 74 and the formation of the input gear 32 are also performed in the gear formation step S3.

The second preparation step S4 is, as shown in FIG. 10, a step of forming a second processed inner peripheral surface portion F7 having a smaller diameter than the contact inner peripheral surface portion F5 in part or all of the region other than the defined region D1. be. In this embodiment, the second processed inner peripheral surface portion F7 has a larger diameter than the first processed inner peripheral surface portion F6. In the present embodiment, the gear shaft 7 is rotated about its axis while the end portion of the gear shaft 7 on the second side L2 in the axial direction is held by a chuck (not shown). By inserting a cutting tool such as a drill from the end of the first side L1, the second processed inner peripheral surface portion F7 is formed. In this example, in the second preparation step S4, the second processed inner peripheral surface portion F7 is also formed in the defined region D1 by cutting the first processed inner peripheral surface portion F6 with a cutting tool. Further, in this embodiment, the cutting tool is passed through the entire area of the gear shaft 7 in the axial direction L, and the entire area other than the specified area D1 and a part of the specified area D1 (the first machined inner peripheral surface portion F6 are formed). area), a second machined inner peripheral surface portion F7 is formed.

The inner circumference forming step S5 is, as shown in FIG. 11, a step of forming an enlarged diameter inner circumference surface portion F3, a stepped portion F4, and a contact inner circumference surface portion F5. In the inner circumference forming step S5, the gear shaft 7 is rotated while holding the end of the gear shaft 7 on the second side L2 in the axial direction, and a part of the second machined inner circumference surface F7 is cut by a cutting tool 11 such as a cutting tool. By cutting, the enlarged diameter inner peripheral surface portion F3, the stepped portion F4, and the contact inner peripheral surface portion F5 are formed by continuous cutting. At this time, the edge portion F41 on the radially inner side R2 of the stepped portion F4 formed at the boundary portion between the contact inner peripheral surface portion F5 and the expanded diameter inner peripheral surface portion F3 has an arcuate cross section that protrudes radially inwardly R2. The stepped portion F4 and the contact inner peripheral surface portion F5 are formed by continuous cutting so as to form a circular ring. As a result, the portion of the edge portion F41 of the stepped portion F4 that is connected to the contact inner peripheral surface portion F5 is formed in a shape in which the tangent line is parallel to the axial direction L and has the same diameter as the contact inner peripheral surface portion F5. Become. Therefore, the step portion F4 and the contact inner peripheral surface portion F5 are smoothly connected to each other.

The lid arranging step S6 is a step of arranging the lid member 75 on the contact inner peripheral surface portion F5. In the lid placement step S6, the lid member 75 is pushed into the first opening 76, and the lid member 75 is placed on the contact inner peripheral surface portion F5 so that the outer edge of the lid member 75 contacts the contact inner peripheral surface portion F5. In this example, as shown in FIG. 4, a lid member 75 is arranged between the oil discharge portion 10 and the stepped portion F4 in the axial direction L. As shown in FIG. When the lid member 75 is inserted into the internal space S in this manner, the outer edge of the lid member 75 moves toward the second axial side L2 while being guided radially inward R2 by the stepped portion F4, and reaches the contact inner peripheral surface portion F5. be guided to At this time, the edge portion F41 of the radially inner side R2 of the stepped portion F4 has an annular shape with an arcuate cross-section that protrudes toward the radially inner side R2, and the stepped portion F4 and the contact inner peripheral surface portion F5 are formed in an annular shape. Since they are connected smoothly, the possibility that the lid member 75 will have unnecessary protrusions when the lid member 75 is arranged can be reduced.

2. Other Embodiments Next, other embodiments of the gear shaft and the method for manufacturing the gear shaft will be described.

(1) In the above-described embodiment, the method for manufacturing the gear shaft 7 has been described as an example of the configuration including the first preparation step S1 and the second preparation step S4. However, it is not limited to such a configuration. For example, in the method of manufacturing the gear shaft 7, one or both of the first preparation step S1 and the second preparation step S4 may be omitted.

(2) In the above embodiment, the configuration in which the shaft main body 72 is provided with the oil discharge portion 10 has been described as an example. However, the configuration is not limited to such a configuration, and a configuration in which the shaft main body 72 is not provided with the oil discharge portion 10 may be employed. In this case, for example, the lid member 75 may be used as a throttle portion, and the oil F may be discharged to the first side L1 in the axial direction with respect to the lid member 75 . In this case, the lid member 75 is preferably configured to have a through-hole, a groove, or the like that penetrates in the axial direction L. As shown in FIG.

(3) In the above-described embodiment, the lid member 75 has a shape in which the entire outer peripheral edge portion thereof contacts the contact inner peripheral surface portion F5 and does not have a through-hole, a groove portion, or the like penetrating in the axial direction L. Although the configuration has been described as an example, it is not limited to this. For example, the lid member 75 is arranged in the internal space with a part of the outer edge portion of the lid member 75 contacting the contact inner peripheral surface portion F5 and the remaining part of the outer edge portion being separated from the contact inner peripheral surface portion F5. may be Specifically, when the cross section of the contact inner peripheral surface portion F5 is circular, the shape of the outer edge portion of the lid member 75 may be a shape having recesses at a plurality of locations on the circular outer peripheral edge. Further, for example, the lid member 75 may have a through-hole, a groove portion, or the like that penetrates in the axial direction L.

(4) In the above embodiment, the first gear portion 73 is arranged in a region that partially overlaps the enlarged diameter inner peripheral surface portion F3, the stepped portion F4, and the contact inner peripheral surface portion F5 when viewed in the radial direction. explained as an example. However, it is not limited to such a configuration. For example, the first gear portion 73 may be arranged in a region that does not overlap the expanded diameter inner peripheral surface portion F3 and the stepped portion F4 when viewed in the radial direction, but overlaps only a part of the contact inner peripheral surface portion F5. .

(5) In the above embodiment, the configuration in which the entire shaft body 72 is the cylindrical portion 71 has been described as an example, but the present invention is not limited to this. For example, in the shaft main body 72, a partial region in the axial direction L including the end portion of the axial direction first side L1 is the cylindrical portion 71 having the internal space S, and the other region in the axial direction L is the internal space. It may be solid without S. In this case, the second opening 77 is not formed in the shaft body 72 .

(6) In the above embodiment, the stepped portion F4 has a stepped surface inclined toward the radially outer side R1 toward the first axial side L1. is not limited. For example, the stepped portion F4 may have a stepped surface along a direction perpendicular to the axial direction L (radial direction R). Also in this case, the edge portion F41 on the radially inner side R2 of the stepped portion F4 is formed in an annular shape having an arc-shaped cross section that protrudes toward the radially inner side R2.

(7) It should be noted that the configurations disclosed in the respective embodiments described above can be applied in combination with configurations disclosed in other embodiments as long as there is no contradiction. Regarding other configurations, the embodiments disclosed in this specification are merely examples in all respects. Therefore, various modifications can be made as appropriate without departing from the scope of the present disclosure.

3. Outline of the above-described embodiment An outline of the gear shaft and the method for manufacturing the gear shaft described above will be described below.

The gear shaft (7) includes a shaft body (72) having a tubular portion (71), a gear portion (73) provided on the outer peripheral portion of the shaft body (72), and the tubular portion (71). a lid member (75) arranged in the internal space (S) of
One side of the shaft body (72) in the axial direction (L) is defined as the axial direction first side (L1), and the tubular portion (71) is positioned on the axial direction first side (L1) of the shaft body (72). ) opening toward the first side (L1) in the axial direction, and a cylindrical inner peripheral surface (F0) surrounding the inner space (S) of the cylindrical portion (71). and, the cylindrical inner peripheral surface (F0) includes a contact inner peripheral surface portion (F5) which is an inner peripheral surface portion with which the outer edge portion of the lid member (75) contacts, and a contact inner peripheral surface portion (F5) from the contact inner peripheral surface portion (F5) an enlarged diameter inner peripheral surface portion (F3), which is an inner peripheral surface portion having a large diameter; A chamfered portion (F2) having a truncated conical surface that is inclined is formed, and the enlarged diameter inner peripheral surface portion (F3) is aligned with the chamfered portion (F2) in the axial direction (L) and the contact inner peripheral surface portion (F5). A stepped portion (F4) in the radial direction (R) is formed at the boundary portion between the contact inner peripheral surface portion (F5) and the enlarged diameter inner peripheral surface portion (F3), and the stepped portion A radially inner (R2) edge (F41) of (F4) is formed in an annular shape having an arc-shaped cross section that is convex radially inward (R2).

According to this configuration, the edge (F41) on the radially inner side (R2) of the stepped portion (F4) is formed in an annular shape having an arc-shaped cross section, so that the contact inner peripheral surface portion (F5) and this It is possible to smoothly connect the contact inner peripheral surface portion (F5) with the enlarged diameter inner peripheral surface portion (F3) adjacent to the first side (L1) in the axial direction. Therefore, when the lid member (75) is inserted from the opening (76) and installed in the internal space (S), the lid member (75) is positioned between the contact inner peripheral surface portion (F5) and the enlarged diameter inner peripheral surface portion (F3). It is possible to avoid scraping by the stepped portion (F4) of the boundary portion between and, and reduce the possibility of generating unnecessary protrusions such as burrs and cut pieces on the lid member (75).

Further, according to this configuration, the enlarged diameter inner peripheral surface portion (F3) is formed between the chamfered portion (F2) and the contact inner peripheral surface portion (F5) in the axial direction (L), so that the chamfered portion ( It is possible to make the diameter of the radially inner (R2) edge of F2) larger than that of the lid member (75). Therefore, when the lid member (75) is inserted from the opening (76) and installed in the internal space (S), the lid member (75) is pushed by the radially inner (R2) edge of the chamfered portion (F2). You can avoid being cut. Therefore, it is possible to eliminate the need to process the radially inner (R2) edge of the chamfered portion (F2) into a smooth shape, thereby avoiding additional processing of the chamfered portion (F2). As a result, the same chamfered portion (F2) can be used as a reference plane through a plurality of machining steps, so machining accuracy can be maintained.
As described above, according to this configuration, when the lid member (75) is installed while maintaining the machining accuracy of the gear shaft (7), the gear shaft (7) is unlikely to have unnecessary projections on the lid member (75). ) can be provided.

Here, the gear portion (73) is provided in a region of the outer peripheral surface of the shaft body (72) overlapping the contact inner peripheral surface portion (F5) when viewed in the radial direction (R). and is suitable.

In such a configuration, since the chamfered portion (F2) is often used as a reference during machining to form the gear portion (73), the same chamfered portion (F2) is used as a reference surface through a plurality of machining processes. It is particularly suitable to have the above configuration that allows

Further, the opening (76) is defined as a first opening (76), the side opposite to the axial direction first side (L1) is defined as an axial direction second side (L2), and the tubular portion (71) is a second opening (77) opening toward the second axial side (L2) at the end of the second axial side (L2); The shaft body (72) includes the inner space (S) penetrating from the portion (76) to the second opening (77), and the shaft body (72) includes the second opening (77) in the axial direction (L) and the It is preferable to have an oil discharge portion (10) disposed between the lid member (75) and penetrating in the radial direction (R).

According to this configuration, the oil (F) supplied to the portion on the axial second side (L2) of the lid member (75) in the internal space (S) is discharged to the outside from the oil discharge portion (10). can do. Since the lid member (75) is arranged in the internal space (S), the lid member (75) moves the lid member (75) in the internal space (S) to the first axial side (L1 ) can be adjusted. As a result, the gear shaft can be used as a supply path for appropriately supplying oil to the gear shaft and other members. Further, as described above, the generation of unnecessary projections on the lid member (75) can be suppressed to a low level, so that unnecessary projections detached from the lid member (75) can be prevented from flowing together with the oil (F).

A method of manufacturing a gear shaft comprises: a shaft body (72) having a tubular portion (71); a gear portion (73) provided on the outer peripheral portion of the shaft body (72); and a lid member (75) arranged in the inner space (S) of the cylindrical portion, with one side in the axial direction (L) of the shaft main body (72) as the first side (L1) in the axial direction. (71) comprises an opening (76) opening toward the first axial side (L1) at the end of the shaft body (72) on the first axial side (L1); A method for manufacturing a gear shaft (7) comprising a cylindrical inner peripheral surface (F0) surrounding the internal space (S) of (71),
A chamfer forming step (S2) of forming a chamfered portion (F2) in the shape of a truncated cone that is inclined radially outward (R1) toward the axial first side (L1) in the opening (76) (S2). And, after the chamfer formation step (S2), a gear formation step (S3) for forming the gear portion (73) in a state in which the chamfer portion (F2) is positioned as a reference, and the gear formation step (S3 ), as the cylindrical inner peripheral surface (F0), a contact inner peripheral surface portion (F5) which is an inner peripheral surface portion with which the outer edge of the lid member (75) contacts, and a contact inner peripheral surface portion (F5) larger than the contact inner peripheral surface portion (F5). An inner periphery forming step (S5) for forming an enlarged diameter inner peripheral surface portion (F3), which is a diameter inner peripheral surface portion, and a lid placement step for placing the lid member (75) on the contact inner peripheral surface portion (F5). (S6), wherein, in the inner circumference forming step (S5), the enlarged diameter inner circumference surface portion (F3) is formed such that the chamfered portion (F2) in the axial direction (L) and the contact inner circumference surface portion (F5 ), and a stepped portion (F4) in the radial direction (R) is formed at the boundary portion between the contact inner peripheral surface portion (F5) and the enlarged diameter inner peripheral surface portion (F3), and the stepped portion ( The contact inner peripheral surface portion (F5) and The point is that the step portion (F4) and the diameter-enlarged inner peripheral surface portion (F3) are formed by continuous cutting.

According to this configuration, in the inner circumference forming step (S5), the radially inner (R2) edge (S41) of the stepped portion (S4) is formed into an annular shape having an arc-shaped cross section, A boundary portion between the contact inner peripheral surface portion (F5) and the enlarged diameter inner peripheral surface portion (S3) adjacent to the contact inner peripheral surface portion (F5) on the axial direction first side (L1) can be smoothly connected. Therefore, when the lid member (75) is inserted from the opening (76) and installed in the internal space (S) in the lid placement step (S6), the lid member (75) expands with the contact inner peripheral surface portion (F5). It is possible to avoid scraping by the stepped portion (F4) at the boundary portion with the diametrically inner peripheral surface portion (F3), and reduce the possibility of generating unnecessary protrusions such as burrs and cut pieces on the lid member (75).

Further, according to this configuration, in the inner circumference forming step (S5), the enlarged diameter inner circumference (F4) is formed between the chamfered portion (F2) and the contact inner circumference (F5) in the axial direction (L). As a result, the diameter of the radially inner (R2) edge of the chamfered portion (F2) can be made larger than that of the lid member (75). Therefore, when the lid member (75) is inserted from the opening (76) and installed in the internal space (S), the lid member (75) is pushed by the radially inner (R2) edge of the chamfered portion (F2). You can avoid being cut. Therefore, it is possible to eliminate the need to process the radially inner (R2) edge of the chamfered portion (F2) into a smooth shape, thereby avoiding additional processing of the chamfered portion (F2). As a result, the same chamfered portion (F2) can be used as a reference plane through a plurality of machining steps, so machining accuracy can be maintained.
As described above, according to this configuration, when the lid member (75) is installed while maintaining the machining accuracy of the gear shaft (7), the gear shaft (7) is unlikely to have unnecessary projections on the lid member (75). ) can be provided.

Further, a first preparation step (S1), which is a step before the chamfer formation step (S2), is further provided, and the side opposite to the axial direction first side (L1) is defined as an axial direction second side (L2), In the first preparation step (S1), from the axial first side (L1) end of the shaft body (72) toward the axial second side (L2), the A first processed inner peripheral surface portion (F6) having a smaller diameter than the contact inner peripheral surface portion (F5) is formed in a specified region (D1) that is a partial region in the axial direction (L), and the chamfer forming step ( In S2), the chamfered portion (F2) is formed so as to be continuous with the first processed inner peripheral surface portion (F6), and after the gear forming step (S3), one of the regions other than the specified region (D1) is formed. It is preferable to further include a second preparation step (S4) of forming a second processed inner peripheral surface portion (F7) having a diameter smaller than that of the contact inner peripheral surface portion (F5) on all or part of the contact inner peripheral surface portion (F5).

According to this configuration, since the first processing inner peripheral surface portion (F6) is formed in the specified region (D1) by the first preparation step (S1) prior to the chamfering forming step (S2), the first processing inner peripheral surface portion (F6) The chamfered portion (F2) can be formed so as to be continuous with the face portion (F6), thereby facilitating the chamfer forming step (S2). Further, when performing the gear forming step (S3), the chamfered portion (F2) has already been formed, so the gear portion (73) is formed in a state in which the centering is performed with reference to the chamfered portion (F2). can do. In addition, by forming the first machined inner peripheral surface portion (F6) in the set region (D1), which is a partial region of the shaft body (72), the region of the set region (D1) of the shaft body (72) is centered. It can be the actual situation. Therefore, when forming the gear portion (73) in the gear forming step S3, the shaft body (72) can be made difficult to deform.

A technique according to the present disclosure is a gear including a shaft body having a cylindrical portion, a gear portion provided on the outer peripheral portion of the shaft body, and a lid member disposed in the inner space of the cylindrical portion. It can be used for a shaft and its gear shaft manufacturing method.

7: gear shaft 10: oil discharge portion 71: cylindrical portion 72: shaft body 73: first gear portion (gear portion)
75: Lid member 76: First opening (opening)
77: Second opening D1: Defined area F0: Cylindrical inner peripheral surface F2: Chamfered portion F3: Expanded diameter inner peripheral surface portion F4: Stepped portion F41: Edge portion F5: Contact inner peripheral surface portion F6: First processed inner peripheral surface portion F7: Second machined inner peripheral surface portion L: Axial direction L1: Axial direction first side L2: Axial direction second side S: Internal space S1: First preparation step S2: Chamfer formation step S3: Gear formation step S4: Second Preparatory step S5: inner periphery forming step S6: lid placement step

Claims (7)

A gear shaft comprising a shaft body having a cylindrical portion, a gear portion provided on the outer peripheral portion of the shaft body, and a lid member disposed in the inner space of the cylindrical portion,
With one side in the axial direction of the shaft main body as the first side in the axial direction,
The cylindrical portion includes an opening portion that opens toward the first axial side at the end portion of the shaft main body on the first axial side, and a cylindrical inner peripheral surface that surrounds the internal space of the cylindrical portion. and
The cylindrical inner peripheral surface includes a contact inner peripheral surface portion that is an inner peripheral surface portion with which the outer edge portion of the lid member contacts, and an enlarged diameter inner peripheral surface portion that is larger in diameter than the contact inner peripheral surface portion and the outer diameter of the lid member. and an inner peripheral surface,
A chamfered portion in the shape of a truncated cone that is inclined radially outward toward the first side in the axial direction is formed in the opening,
The enlarged diameter inner peripheral surface portion is arranged between the chamfered portion and the contact inner peripheral surface portion in the axial direction,
A radially stepped portion is formed at a boundary portion between the contact inner peripheral surface portion and the enlarged diameter inner peripheral surface portion,
The radially inner edge of the stepped portion is a circle having an arc-shaped cross section that protrudes radially inward so as to come into contact with the outer edge of the lid member when the lid member is inserted into the internal space. A gear shaft that is an annular portion that is formed in an annular shape. 2. The method according to claim 1, wherein the radially inner edge of the annular portion is smaller than the outer diameter of the lid member, and the radially outer edge of the annular portion is larger than the outer diameter of the lid member. gear shaft. The opening has a truncated conical relief surface inclined radially outward toward the first side in the axial direction on the first side in the axial direction with respect to the chamfered portion,
an inclination angle of the relief surface portion with respect to the axial direction is larger than an inclination angle of the chamfered portion with respect to the axial direction,
The enlarged diameter inner peripheral surface portion, the stepped portion, and the contact inner peripheral surface portion are formed so as to be positioned radially outward with respect to an imaginary conical surface including the truncated conical surface of the chamfered portion. 3. A gear shaft according to item 1 or 2. The gear according to any one of claims 1 to 3 , wherein the gear portion is provided in a region of the outer peripheral surface of the shaft body that overlaps the contact inner peripheral surface portion when viewed in a radial direction along the radial direction. shaft. The opening is defined as a first opening, and the side opposite to the axial direction first side is defined as an axial direction second side,
The cylindrical portion has a second opening that opens toward the second axial side at an end on the second axial side, and the shaft main body is moved from the first opening to the second opening. The internal space that penetrates to
5. The shaft body according to any one of claims 1 to 4 , wherein the shaft body is provided with an oil discharge portion disposed between the second opening and the lid member in the axial direction and penetrating in the radial direction. gear shaft. A shaft main body having a cylindrical portion, a gear portion provided on the outer peripheral portion of the shaft main body, and a lid member disposed in the inner space of the cylindrical portion, the shaft main body With the first side in the axial direction, the tubular portion has an opening portion that opens toward the first side in the axial direction at the end portion of the shaft main body on the first side in the axial direction; A method for manufacturing a gear shaft comprising a cylindrical inner peripheral surface surrounding an inner space,
a chamfer forming step of forming a chamfered portion in the shape of a truncated cone that is inclined radially outward toward the first side in the axial direction in the opening;
After the chamfer forming step, a gear forming step of forming the gear portion in a state where the gear portion is positioned with reference to the chamfered portion;
After the gear forming step, the cylindrical inner peripheral surface includes a contact inner peripheral surface portion which is an inner peripheral surface portion in contact with the outer edge portion of the lid member, and a contact inner peripheral surface portion having a larger diameter than the outer diameter of the contact inner peripheral surface portion and the lid member. an inner periphery forming step of forming an enlarged diameter inner peripheral surface portion which is an inner peripheral surface portion;
a lid arranging step of arranging the lid member on the contact inner peripheral surface,
In the inner circumference forming step, the enlarged diameter inner peripheral surface portion is formed between the chamfered portion and the contact inner peripheral surface portion in the axial direction, and is a boundary between the contact inner peripheral surface portion and the enlarged diameter inner peripheral surface portion. A radially stepped portion is formed in the portion, and a radially inner edge of the stepped portion protrudes radially inward so as to contact an outer edge portion of the lid member when the lid member is inserted into the internal space. A method for manufacturing a gear shaft , wherein the contact inner peripheral surface portion, the stepped portion, and the diameter-enlarged inner peripheral surface portion are continuously cut to form an annular portion having an arc-shaped cross section. Further comprising a first preparation step which is a step prior to the chamfer formation step,
With the side opposite to the axial direction first side as the axial direction second side,
In the first preparation step, from an end portion of the shaft main body on the first axial side toward the second axial side, a prescribed region that is a partial region of the shaft main body in the axial direction is provided with the forming a first processed inner peripheral surface portion having a smaller diameter than the contact inner peripheral surface portion;
In the chamfer forming step, the chamfered portion is formed so as to be continuous with the first processed inner peripheral surface portion,
After the gear forming step, further comprising a second preparation step of forming a second machined inner peripheral surface portion having a smaller diameter than the contact inner peripheral surface portion in part or all of the area other than the specified area . 7. The method for manufacturing the gear shaft according to 6 .

Images