JP2002372125A - Shaft body manufacturing method, cam shaft, shaft- integrated gear, and crank shaft - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a shaft body manufacturing method capable of simply and inexpensively manufacturing an integrated cam shaft or the like which is manufactured by cutting. SOLUTION: The cam shaft 1 comprises a shaft part 2 and first to fourth cam parts 3-6, and the cam parts 3, 5 and 6 comprise first and second longitudinally split pieces 31, 32, 51, 52, 61 and 62. The shaft part 2, each split piece and the second cam part are respectively manufactured, assembled, and fitted between conductive electrodes 73 and 76 of a conductive joining machine 70 of a conductive joining equipment 7, and the DC current or the pulse current is allowed to run under the predetermined pressure for the predetermined time, and left for the predetermined time in a predetermined heated condition in a heat treatment machine 80. As a result, the cam shaft with each joining surface joined with the joining strength equivalent to the strength of the base material is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of manufacturing a shaft such as a camshaft or a shaft-integrated gear by joining a plurality of parts, and a camshaft and a shaft manufactured by the method. The present invention relates to a body gear and a crankshaft. More specifically, a method of manufacturing a shaft body by manufacturing a shaft body by joining a plurality of parts using a new current-carrying method different from a discharge plasma sintering method or a hot press bonding method, and a cam shaft, The present invention relates to a shaft-integrated gear and a crankshaft.

[0002]

2. Description of the Related Art A camshaft for controlling the opening and closing of a supply / exhaust valve in an internal combustion engine is provided with a shaft portion and a plurality of disc-shaped cams formed on an outer peripheral surface of the shaft portion. Generally, it is manufactured by cutting a forged product. Alternatively, it is manufactured by separately manufacturing a shaft portion and a disc-shaped cam having a shaft hole formed thereon, and fixing the disc-shaped cam to the shaft portion using welding or a pin. A crankshaft and the like are similarly manufactured, and a shaft-integrated gear, a valve with a valve shaft and the like are similarly manufactured.

[0003] The manufacturing method in which a disc-shaped cam or the like is fixed to the shaft portion by welding or the like has disadvantages such as insufficient joining strength between the two members, and the method of cutting a forged product is not reliable in terms of strength. Is high. However, there is a problem that cutting is expensive and requires a long processing time.

[0004]

Here, if such a shaft body can be manufactured by firmly joining the entire joint surface of a plurality of parts without using an existing joining method such as welding, it is inexpensive. This is preferable because a highly reliable shaft can be manufactured efficiently.

[0005] Further, since the camshaft and the like slide constantly at high speed and generate heat, it is necessary to constantly cool it with oil or the like. Conventionally, cooling is performed by spraying oil or the like from the outside. It is desirable that a cam or the like can be manufactured by stacking the divided pieces so that a passage for circulating oil as a refrigerant can be formed on these mating surfaces and an internal cooling structure can be realized.

In order to perform such joining, for example,
A hot press joining method in which a direct current is passed between members to be joined under a predetermined pressure, or a discharge plasma sintering method (SP) in which a direct current pulse is passed between them to perform sintering.
It is conceivable to employ a joining method utilizing the principle of S).

However, in the latter joining method using the SPS technology, the members to be joined need to be put in a graphite mold and joined in the mold, so that the joining operation is complicated. There are drawbacks such as a great limitation on the shape and dimensions of the joining members, and furthermore, there is a drawback that sufficient joining strength cannot be obtained. As a joining method utilizing the principle of the spark plasma sintering method, see Japanese Patent Application Laid-Open No. 11-1585.
However, in the method disclosed here, it is necessary to roughen the joint surface, and the method cannot be used for joining the mirror-finished joint surface. There is a disadvantage that a high joining strength cannot be obtained.

On the other hand, when the former hot press joining method is used for joining bulk materials, it takes time and cost, but has the disadvantage that it is difficult to obtain sufficient joining strength.

[0009] The object of the present invention is to solve the above problems.
An object of the present invention is to propose a method of manufacturing a shaft body that can be manufactured by firmly joining a plurality of components to a shaft body having a portion protruding in a radial direction such as a cam.

Another object of the present invention is to propose a camshaft, an integral crankshaft and an integral shaft gear manufactured by such a novel method for manufacturing a shaft.

[0011]

SUMMARY OF THE INVENTION To solve the above problems, the present invention provides a shaft having a shaft portion and at least one radially protruding radially projecting portion joined to the shaft portion. A method of manufacturing a body, wherein the radially projecting portion is manufactured as at least first and second split pieces, and at least the first split piece is formed with an insertion hole for inserting the shaft portion. The shaft portion is inserted into the insertion hole of the first divided piece, and the first and second divided pieces are overlapped; in this state, the outer peripheral surface of the shaft portion and the insertion hole are inserted. Forming a state in which the inner peripheral surface of the shaft is pressed with a predetermined pressure, and a state in which the joint surfaces of the first and second divided pieces are pressed with a predetermined pressure to each other; Part, the first
DC current and / or
Alternatively, by passing a pulse current, between the shaft portion and the first split piece, and between the first and second split pieces,
Temporarily joining; wherein the shaft portion, the first divided piece, and the second divided piece in the temporarily joined state are heat-treated at a predetermined atmospheric temperature.

[0012] Here, after the divided pieces are first temporarily joined to form a radially protruding portion, this and the shaft portion may be temporarily joined, and then heat treatment may be performed. That is, the radially projecting portion is manufactured as at least first and second divided pieces, and at least the first divided piece is formed with an insertion hole for inserting the shaft portion; Superimposing the first and second divided pieces; in this state, forming a state in which the joining surfaces of the first and second divided pieces are pressed against each other with a predetermined pressure;
While maintaining the pressed state, a DC current and / or a pulse current is passed through the first divided piece and the second divided piece to temporarily join the first and second divided pieces; The shaft portion is inserted into the shaft hole of the first divided piece in a temporarily joined state; in this state, the outer peripheral surface of the shaft portion and the inner peripheral surface of the shaft hole are pressed with a predetermined pressure. A DC current and / or a pulse current is passed through the shaft portion and the first and second divided pieces in the temporarily joined state while maintaining the pressed state, and a gap is formed between these. Temporarily joining; The shaft portion, the first divided piece, and the second divided piece in the temporarily joined state may be heat-treated at a predetermined ambient temperature.

Here, it is desirable that the pressure be 50 megapascals or less. It is desirable that the heat treatment be performed in an inert atmosphere. Further, it was confirmed that it is desirable to set the temperature of the heat treatment to a temperature range of 85% or less of the lowest melting point of the members to be joined.

Next, in order to form a state in which the space between the shaft portion and the shaft hole of the first divided piece is pressed with a predetermined pressure, the outer diameter of the shaft portion with respect to the inner diameter of the shaft hole is required. The diameter is made slightly smaller, specifically, the clearance is made as small as possible within an insertable range, and the shaft portion is inserted into the shaft hole of the first split piece, and these shaft portions and the first The divided piece may be heated to a predetermined temperature by flowing a direct current and / or a pulse current to form a thermally expanded state.

[0015] The divided piece of the radially protruding portion can be as follows. First, the first and second divided pieces both form the insertion hole, and one side of the radially projecting portion in the direction of the center axis is the first divided piece, and the other side is the first divided piece. It can be a second divided piece.
Alternatively, a radially inner portion of the radially projecting portion may be the first split piece, and a radially outer portion may be the second split piece.

In order to form a circulation path for circulating a heat medium, a refrigerant, or a lubricating oil inside the radially protruding portion, at least one of the joints in the first and second divided pieces is required. A groove for flowing a heat medium, a refrigerant, or a lubricating oil may be formed on the surface. When both divided pieces are joined, a circulation path is formed on the mating surface. In this case, a flow path for supplying a heat medium or a coolant to the groove may be formed inside the shaft portion.

When a groove for allowing lubricating oil to flow is formed on at least one of the joining surfaces of the first and second divided pieces, the groove is formed on the outer periphery of the radially projecting portion. What is necessary is just to connect to the opening part for oil blowing formed in the surface.

The manufacturing method of the present invention can be applied to the manufacture of camshafts, shaft-integrated gears, and integrated crankshafts. If the manufacturing method of the present invention is used, the reliability with sufficient joint strength can be improved. High camshafts can be manufactured. Further, a camshaft having a circulation path for a refrigerant, lubricating oil, and the like inside can be easily manufactured.

[0019]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, an example of a camshaft manufactured by the manufacturing method of the present invention and an example of the manufacturing method will be described with reference to the drawings.

(Cam Shaft) FIG. 1 is a plan view showing a cam shaft of this embodiment. The camshaft 1 of the present embodiment includes a shaft portion 2 having a circular cross section,
Four disc-shaped cams joined to the outer peripheral surface 21 of the shaft portion 2, that is, first to fourth cam portions 3, 4, 5,.
6 is provided. The first cam portion 3 is formed by joining first and second divided pieces 31 and 32, which are bisected in the axial direction, to each other.
Similarly, the first and second split pieces 51 and 52 are joined together, and the fourth cam portion 6 is likewise constituted by joining the first and second split pieces 61 and 62. I have.

Next, the structure of each part will be described with reference to FIGS. First, FIG. 2 is a plan view, a longitudinal sectional view, and a transverse sectional view showing the shaft portion 2. As shown in these figures, the shaft portion 2 is a shaft portion having a circular cross-section and a fixed length, and its outer peripheral surface 21 has protrusions for cam rotation prevention extending in the direction of the axis 2a at both ends in the diametrical direction. Article 22,
23 are formed. From both end surfaces 24 and 25 of the shaft portion 2, a coolant passage 2 having a constant depth along the direction of the axis 2a.
6 and 27 are formed, and these coolant passages 26 and 27 are formed.
The bottom portion of 27 has diametrically extending coolant passages 28, 2
9 in communication. Both ends of each of the coolant passages 28 and 29 have openings 28a, 28b and 29a exposed on the outer peripheral surface 21.
29b.

FIGS. 3A to 3D show the first cam 3.
3A and 3B are a perspective view and a cross-sectional view illustrating a first divided piece 31 of the first embodiment, and a perspective view and a cross-sectional view illustrating a second divided piece 32. The first split piece 31 is formed with a shaft hole 311 at the center of which the shaft portion 2 is inserted.
The above-described anti-rotation ridges 22 and 23 which also serve for positioning.
Are formed in the recesses 313 and 314 for stopping rotation. The outer peripheral surface is a cam surface 315. In addition, other structures, such as using a pin, can be used for the structure for positioning and rotation prevention.

In this embodiment, the first and second divided pieces 31,
The joining surface of 32 is a plane orthogonal to the central axis. Of course, it may be an inclined surface or a complementary curved surface. The joint surface 316 of the first divided piece 31 with the second divided piece 32 has two grooves 317, 3
18 are formed. Groove 317 for one coolant passage
Extends radially from the inner peripheral surface 312, extends in a semicircular shape along the outer peripheral surface at a position near the outer peripheral surface, further extends inward in the radial direction from its tip, and has an end near the inner peripheral surface 312. positioned. The other groove 318 is
It has a point-symmetrical shape with 7.

The second divided piece 32 also has a shaft portion 2 at its center.
The shaft hole 321 through which the rotation-stopping protrusions 22 and 23 are fitted is formed on the inner peripheral surface 322 of the shaft hole 321. The outer peripheral surface is a cam surface 325. Two cooling liquid passages 327 and 328 are formed on the joint surface 326 of the second divided piece 32 with the first divided piece 31 so as to extend therethrough in the central axis direction. One end of one coolant passage 327 is located at a position corresponding to the end of the coolant passage groove 318, and one end of the other coolant passage 328 is located at a position corresponding to the end of the coolant passage groove 317. Also, the other end face of the second divided piece 32 is the second cam portion 4
And a joining surface 329.

The first and second divided pieces 31, 32
To form a first cam portion 3,
Two grooves 31 are provided between the joining surfaces 316 and 326.
7, 318, the two coolant passages 317a, 31
8a is configured. Also, each coolant passage 31
The openings 7a and 318a on the inner peripheral surface side are in a state of communicating with both end openings 28a and 28b of the coolant passage 28 formed in the shaft portion 2.

FIG. 4 is a perspective view showing the second cam portion. In this embodiment, the second cam portion 4 is formed of a single component, and has a shaft hole 411 formed at the center thereof. Are formed with a pair of concave portions 413 and 414 for stopping rotation. One end surface is a joint surface 419 with the first cam portion 3, and the other end surface is a joint surface 429 with the third cam portion 5. The outer peripheral surface 415 is a cam surface. Furthermore, the first cam portion 3
At positions corresponding to the pair of coolant passages 327 and 328 in the coolant passage 41 extending through the center axis direction.
7, 418 are formed.

FIGS. 5A to 5D are a perspective view and a sectional view showing a first divided piece of the third cam portion 5. FIG.
It is a perspective view and a sectional view showing a second divided piece.
The first divided piece 51 has a shaft hole 511 at the center thereof through which the shaft portion 2 is inserted, and the above-described anti-rotation ridges 22 and 23 fit into the inner peripheral surface 512 thereof. Depressions 513 and 514 for stopping rotation are formed. Also,
The outer peripheral surface is a cam surface 515.

The first divided piece 51 has two coolant passages 517b and 517b extending through the center axis thereof at positions corresponding to the coolant passages 417 and 418, respectively.
8b are formed. In addition, a joint surface 516 with the second divided piece 52 has two grooves 517 for a coolant passage,
518 are formed. Groove 51 for one coolant passage
Numeral 7 extends radially outward from a position communicating with the coolant passage 517b, extends in a semicircular shape along the outer peripheral surface at a position near the outer peripheral surface, and further extends radially inward from the distal end thereof to form an inner peripheral surface. The end is located near the surface 512.
The other groove 518 has a point-symmetrical shape with the groove 517, and one end thereof communicates with the coolant passage 518b.
The other end face of the first split piece 51 is the second cam portion 4
519.

The second divided piece 52 also has a shaft portion 2 at its center.
A shaft hole 521 through which the rotation preventing protrusions 22 and 23 are fitted is formed on an inner peripheral surface 522 of the shaft hole 521. The outer peripheral surface is a cam surface 525. Two cooling liquid passages 527, 528 extending through the center axis direction are formed on the joint surface 526 of the second divided piece 52 with the first divided piece 51. One end of one coolant passage 527 is located at a position corresponding to the end of the coolant passage groove 517, and one end of the other coolant passage 528 is located at a position corresponding to the end of the coolant passage groove 518. The other end face of the second divided piece 52 is connected to the fourth cam portion 6.
529.

The first and second divided pieces 51, 52
Are joined to form a third cam portion 5,
Between the joining surfaces 516 and 526, two grooves 51 are provided.
7, 518, the two coolant passages 517a, 51
8a is configured. In addition, each coolant passage 51
7a and 518a are in a state of communicating with the cooling passages 417 and 418 of the second cam portion 4, respectively.

FIGS. 6A to 6D are a perspective view and a sectional view showing the first divided piece of the fourth cam portion 6, and a perspective view and a sectional view showing the second divided piece. The first split piece 61 has a shaft hole 611 at the center thereof through which the shaft portion 2 is inserted, and the above-described anti-rotation ridges 22 and 23 fit into the inner peripheral surface 612 thereof. Depressions 613 and 614 for stopping rotation are formed. The outer peripheral surface is a cam surface 515.

The first divided piece 61 has two coolant passages 617b and 61 extending through the center axis direction at positions corresponding to the coolant passages 517 and 518, respectively.
8b are formed. In addition, a joint surface 616 with the second divided piece 62 has two grooves 617 for a coolant passage,
618 are formed. Groove 61 for one coolant passage
Numeral 7 extends radially outward from a position communicating with the coolant passage 617b, extends in a semicircular shape along the outer peripheral surface at a position near the outer peripheral surface, and further extends inward in the radial direction from the distal end thereof to form the inner peripheral surface. The end is located near the surface 612.
The other groove 618 has a point-symmetrical shape with the groove 617, and one end thereof communicates with the coolant passage 618b.
The other end surface of the first split piece 61 is the third cam portion 5
619.

The second divided piece 62 also has a shaft portion 2 at its center.
A shaft hole 621 is formed through which is inserted, and concave portions 623 and 624 for rotation prevention are formed in the inner peripheral surface 622 thereof so that the protrusions 22 and 23 for rotation prevention are fitted. The outer peripheral surface is a cam surface 625. One end face of the second divided piece 62 is a joint surface 626 with the first divided piece 61.

The first and second divided pieces 61 and 62
Are joined to form a fourth cam portion 6,
Between the joining surfaces 616 and 626, two grooves 61 are provided.
7, 618, two coolant passages 617a, 61
8a is configured. In addition, each coolant passage 61
7a and 618a are in a state of communicating with the cooling passages 518 and 517 of the third cam portion 5, respectively.

The shape of the passage can be various shapes such as a spiral shape. It is also effective that the positioning pins are embedded in each other so as to facilitate the positioning.

(Method of Manufacturing Camshaft) Next, a method of manufacturing the camshaft 1 of this embodiment will be described. First, each component is manufactured as described above. Here, the inner diameter of each of the cam portions 3 to 6 is set to be slightly larger than the outer diameter of the shaft portion 2, and the shaft portion 2 is inserted into the shaft hole of each of the cam portions 3 to 6.
The insertion can be made in a state where the clearance between them becomes as small as possible.

Next, the shaft portion 2 is assembled through the shaft holes of the cam portions 3 to 6. The shaft assembly is mounted on a current-carrying apparatus for carrying out the method of the present invention, and the joining surfaces of the components are joined.

Here, in this example, the shaft portion 2 is passed through the shaft hole of each of the cam portions 3 to 6, and these parts are joined at the same time. May be joined to each other and the shaft portion 2 may be joined.

FIG. 7 shows the overall configuration of the current-carrying apparatus of this embodiment. As shown in this figure, the current-carrying apparatus 7 of this embodiment includes a current-carrying machine 70 and a heat treatment machine 80. The energization bonding machine 70 includes a lower energization electrode 73 that is electrically insulated and fixed to the base 72 by a known method via an insulating member on the base 72, and is disposed above the base 73. A fluid pressure cylinder 74 supported on the base in a known manner, and an upper side fixed to the tip of a piston rod 75 of the fluid pressure cylinder 74 by an insulating member and electrically insulated from the piston rod 75 in a known manner. And a current-carrying electrode 76.

The fluid pressure cylinder 74 functions as a pressure device for pressing the material to be joined. As the pressurizing device, an electric motor, a screw mechanism or the like may be used instead of the fluid pressure cylinder to raise and lower the upper energized electrode. The upper and lower conducting electrodes 73 and 76 are electrically connected to a power supply 77, and the power supply 77 can supply a DC pulse current. The power supply of the power supply device 77 of this example has a voltage of 100 V or less and a current of 2000 to 5
Large current power in the range of 000A. Although the upper energizing electrode 76 is movable in this example, the lower energizing electrode 73 may be movable, or both may be movable.

Next, the heat treatment machine 80 is provided with a vacuum heat treatment furnace having a known structure. In addition, the electric welding machine 7
0 and the heat treatment machine 80 may be integrated into a device, or they may be movable. Of course, these may be arranged separately.

FIG. 8 shows a state where the shaft assembly 9 is mounted between the current-carrying electrodes of the current-bonding machine 70. In this example, the upper energizing electrode 73 and the lower energizing electrode 76 are
Insertion holes 73a, 76a into which both ends of the cam portions 3 can be inserted are formed, and the pressing surfaces 73b, 76b of the current-carrying electrodes 73, 76 are securely attached to the shaft portion 2.
6 can be brought into contact with the end faces 3a, 6a. In addition, since the insertion holes 73a and 76 are formed, the shaft assembly 9 can be easily mounted between the energizing electrodes.

With the shaft assembly 9 mounted as described above,
The fluid pressure cylinder 74 is driven, and the upper energizing electrode 76 is lowered by the piston rod 75. As a result, the first to fourth cam portions 3 to 6 are connected to the energizing electrodes 73 and 76.
And is pressed by a predetermined pressing force. That is, between the joining surfaces 316 and 326, the joining surface 3
29 and 419, between the bonding surfaces 429 and 519, between the bonding surfaces 516 and 526, between the bonding surfaces 529 and 619, and between the bonding surfaces 616 and 626. The pressing force varies depending on the material of the member, but may be 50 MPa or less.

Under such a pressed state, the power supply 77
Then, a DC pulse current having a predetermined value is supplied to the shaft assembly 9 through the conductive electrodes 73 and 76 for a predetermined period. For example, in the case of the embodiment shown in FIG. 1, when the axial length is 200 mm, the shaft diameter is 10 mm, the thickness of the cam portion is 20 mm, and the maximum diameter of the cam portion is 50 mm, the chromium molybdenum steel (SCM41) is used.
When 5) is used, the peak current may be about 3500 A, the peak voltage may be about 5 V, and the peak holding time may be about 30 minutes. These values greatly differ depending on the dimensions of the parts. Further, the material is not limited to the above materials, and various metals including non-ferrous metals can be used.

By energizing the shaft assembly 9 in this manner, the shaft assembly 9 is heated. The shaft portion 2 is inserted into the shaft hole of each of the cam portions 3 to 6 in the shaft assembly 9 with a very small clearance. A state in which a predetermined pressing force acts on the joining surface of is formed. That is, the shaft hole inner peripheral surfaces 312, 322, 412, 512, 52
A state where a predetermined pressing force acts between 2, 612, 622 and the shaft portion outer peripheral surface 21 is formed. Note that a heater may be used instead of heating by passing a direct current and / or a pulse current.

As a result, the joining surfaces are joined to each other. Although the exact principle of this bonding is not always clear, it is considered that bonding is performed by generation of discharge plasma between bonding surfaces, thermal diffusion effect by Joule heat, electrolytic diffusion effect by electric field, and the like.

Incidentally, the outer peripheral surface of each cam portion of the camshaft of this embodiment is a sliding surface, and when it is desired to supply lubricating oil to this sliding surface, the passage provided inside is a lubricating oil passage. It is preferable that a blow-out hole opened in the sliding surface of the cam portion is formed in communication with the flow passage so that the lubricating oil is blown out. In this case, it is more effective than spraying the whole from outside. It is preferable to provide an oil pool at the same time in the blowout hole. Is effective. In this way, if a hole communicating with the flow path is provided on the sliding surface of the camshaft, a lubricating effect can be provided more effectively than spraying oil from the outside.

Here, it is possible to form a state where the joining surfaces are joined to each other even if only a DC current of a predetermined value is passed through the shaft assembly 9 or both a DC current and a pulse current are simultaneously passed. Was confirmed.

The state in which the joining surfaces are joined in this way is not yet complete in terms of joining strength. Therefore, this joint state is called a temporary joint state, and the shaft assembly 9 in the temporary joint state is called a temporary joint body.

The temporary bonded body is heat-treated in a heat treatment furnace of the heat treatment machine 80. The heat treatment temperature and time vary depending on the material and size of the member. By performing heat treatment,
The joining between the joining surfaces in the temporary joining state becomes perfect and becomes a complete joined body. That is, the bonding strength between the bonding surfaces becomes a value comparable to the material strength of the member.

After the heat treatment, the camshaft 1 shown in FIG. 1 is obtained. Since the camshaft 1 is formed by joining a plurality of parts, it can be manufactured at a lower cost and in a shorter time than in a conventional manufacturing by cutting. Also, the joint strength between the shaft portion 2 and each of the cam portions 3 to 6 becomes sufficient.

Further, the camshaft 1 has an internal cooling structure. That is, since the cam portions 3, 5, and 6 are formed by joining the divided pieces, the two coolant passages 327, 4 extending in the axial direction are formed inside thereof.
17, 517b, 527, 617b, and 328,4
18, 518b, 528, and 618b are formed.
Also, diametrically extending passages 317a, 318a, 517a, 518 communicating with these axially extending passages.
a, 617a and 618a are formed. By circulating oil as a coolant through the coolant passages 26 and 27 formed in the shaft portion 2, the cam portions 3 to 6 can be efficiently cooled. It is impossible to manufacture a camshaft having such an internal cooling structure by a conventional technique, and it can be realized only by applying the method of the present invention.

Here, in the above example, each of the cam parts 3, 5, and 6 is vertically divided into two parts, but this is divided into three or more parts, and each divided piece is divided into three parts. You may make it join mutually.

Further, each cam portion may be divided into a radially inner portion and an outer portion, and these may be joined to each other. For example, as shown in FIG. 9, the above-mentioned cam portion 3 is divided into an inner ring portion 301 which is an inner portion in the radial direction and an outer ring portion 302 which is an outer portion.
Make a shaft hole 303 for inserting the shaft part 2 at the center of
The outer peripheral surface 304 of the inner ring portion 301 and the inner peripheral surface 305 of the outer ring portion 302 may be joined to each other. Also in this case, the outer diameter of the outer peripheral surface 304 is made slightly smaller than the inner diameter of the outer ring portion 302, and the two are fitted together and heated, so that a pressing force can be applied therebetween. .

In this case, a groove for forming a coolant passage may be provided between the outer peripheral surface 304 and the inner peripheral surface 305, which are joint surfaces.

(Another Example of Current-Bonding Machine) Next, in the current-bonding apparatus 7 shown in FIGS. The temporary bonded body is sequentially heat-treated in the heat treatment machine 80. Instead, a plurality of temporary bonded bodies may be heat-treated in a batch-type by the heat treatment machine 80.

Further, as shown in FIG.
A, 76A may be a large disk or the like, and a plurality of sets of members to be joined may be mounted between them, and an electric welding machine may be configured so that a plurality of sets of joining members can be temporarily joined at a time.

(Material to be Joined) The above example relates to the manufacture of a camshaft. However, the method of the present invention relates to a method of forming a component having a configuration in which a radially protruding portion is formed on a shaft portion. Applicable to manufacturing. Representative examples include an integral crankshaft of an engine, an integral shaft gear, a valve integral with a valve shaft, and the like. In producing these,
These are divided into a plurality of parts, and the divided parts are manufactured and joined to each other, whereby an integrated part having a cooling liquid passage or the like and sufficient strength therein can be obtained.

[0059]

As described above, according to the present invention, in manufacturing a shaft body having a shaft portion and a radially projecting portion radially projecting from the outer peripheral surface, at least the radially projecting portion is manufactured. After being divided into a plurality of parts and each part is manufactured, they are temporarily bonded by applying a direct current and / or a pulse current while being pressed at a predetermined pressure, and then subjected to a heat treatment.

According to the manufacturing method of the present invention, a shaft, such as a camshaft or a crankshaft, which has been conventionally manufactured as an integral body by cutting, can be manufactured easily and inexpensively from a plurality of parts.

Also, since a plurality of parts can be manufactured by joining, if a groove for a passage of a heat medium, a coolant or the like is formed between these parts, there is an advantage that a shaft having an internal cooling structure can be manufactured. is there.

[Brief description of the drawings]

FIG. 1 is a plan view showing an example of a camshaft manufactured according to the present invention.

FIG. 2 is a plan view, a longitudinal sectional view, and a transverse sectional view showing a shaft portion of the cam shaft of FIG.

FIGS. 3 (a) to 3 (d) show a first cam portion of a first cam portion;
3A and 3B are a perspective view and a cross-sectional view showing a second divided piece, and a perspective view and a cross-sectional view showing a second divided piece.

FIG. 4 is a perspective view and a sectional view of a second cam portion.

5 (a) to 5 (d) show first cam portions of a third cam portion. FIG.
3A and 3B are a perspective view and a cross-sectional view showing a second divided piece, respectively.

FIGS. 6 (a) to (d) show a first cam portion of a fourth cam portion;
3A and 3B are a perspective view and a cross-sectional view showing a second divided piece, respectively.

FIG. 7 is a schematic configuration diagram showing an example of a current-carrying apparatus for performing the method of the present invention.

FIG. 8 is an explanatory view showing a state where a shaft assembly is mounted on an electric welding machine of the electric welding apparatus of FIG. 7;

FIG. 9 is an explanatory diagram showing another example of a method of dividing a cam portion.

FIG. 10 is an elevational view showing another example of the current welding machine and an explanatory view showing a mounted state of a member to be welded.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 camshaft 2 shaft portion 21 outer peripheral surface 3 first cam portion 31, 32 split piece 4 second cam portion 5 third cam portion 51, 52 split piece 6 fourth cam portion 61, 62 split piece 312, 322, 412, 512, 522, 612, 6
22 Inner peripheral surface of shaft hole 316, 326, 329, 419, 429, 519, 5
16, 526, 529619, 616, 626 Joining surfaces 317, 318, 417, 418, 517, 518, 6
17,618 Groove 7 Current bonding machine 70 Current bonding machine 80 Heat treatment machine

[Procedure amendment]

[Submission date] July 4, 2001 (2001.7.4)

[Procedure amendment 1]

[Document name to be amended] Drawing

[Correction target item name] All figures

[Correction method] Change

[Correction contents]

FIG.

FIG. 2

FIG. 4

FIG. 3

FIG. 5

FIG. 6

FIG. 7

FIG. 8

FIG. 9

FIG. 10

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F16H 55/17 F16H 55/17 AZ // B23K 20/00 310 B23K 20/00 310A F term (reference) 3G016 BA25 BA33 BA34 CA06 FA15 FA30 FA33 3J030 AC03 BA01 BD06 CA10 EA14 EB09 EC04 EC07 3J033 AA02 AA10 AC01 BA02 BA07 BA08 BA12 BA14 4E067 BA00 DA05 DC01 EB00

Claims (17)

[Claims] 1. A method of manufacturing a shaft having a shaft portion and at least one radially projecting radially projecting portion joined to the shaft portion, wherein the radially projecting portion is at least a first It is manufactured as first and second split pieces, and at least the first split piece is formed with an insertion hole for inserting the shaft portion, and the shaft portion is inserted into the first split piece. A state in which the outer peripheral surface of the shaft portion and the inner peripheral surface of the insertion hole are pressed with a predetermined pressure in this state, while the first and second divided pieces are overlapped with each other; Forming a state in which the joint surfaces of the second and the second divided pieces are pressed against each other with a predetermined pressure, and while maintaining the pressed state, the shaft portion, the first divided piece and the second divided piece are DC current and / or pulse current Flowing, temporarily joining between the shaft portion and the first divided piece, and between the first and second divided pieces, the shaft portion in a temporarily joined state, the first divided piece And a heat treatment of the second divided piece at a predetermined atmospheric temperature. 2. A method for manufacturing a shaft body having a shaft portion and at least one radially projecting radially projecting portion joined to the shaft portion, wherein the radially projecting portion is formed in at least a first direction. In addition to manufacturing as the first and second split pieces, at least the first split piece is formed with an insertion hole for inserting the shaft portion, and the first and second split pieces are overlapped, In this state, a state is formed in which the joining surfaces of the first and second divided pieces are pressed against each other with a predetermined pressure, and the first divided piece and the second divided piece are held while maintaining the pressed state. A DC current and / or a pulse current is applied to the first and second segments to allow a gap between the first and second segments;
Temporarily joining, and inserting the shaft portion into the shaft hole of the first divided piece in the temporarily joined state. In this state, the outer peripheral surface of the shaft portion and the inner peripheral surface of the shaft hole are subjected to a predetermined pressure. A DC current and / or a pulse current is passed through the shaft portion and the first and second divided pieces in a temporarily joined state while maintaining the pressed state. Wherein the shaft portion, the first split piece, and the second split piece in the temporarily joined state are heat-treated at a predetermined atmospheric temperature. 3. The method according to claim 1, wherein the pressure is set to 50 megapascals or less. 4. The method for manufacturing a shaft according to claim 1, wherein the heat treatment is performed in an inert atmosphere. 5. The method according to claim 1, wherein the temperature of the heat treatment is set at 8 which is the lowest melting point of the member to be joined.
A method for producing a shaft body, wherein the temperature range is 5% or less. 6. The shaft part and the first divided piece according to claim 1 or 2, wherein the dimensions of the shaft part are formed slightly smaller than the dimensions of the insertion hole of the first divided piece. A method of manufacturing a shaft, wherein a state is formed in which the outer peripheral surface of the shaft portion and the inner peripheral surface of the insertion hole are pressed with a predetermined pressure by thermal expansion. 7. The device according to claim 1, wherein each of the first and second divided pieces includes the insertion hole, and one side of the radially projecting portion in a direction of a center axis is the first divided piece. A method of manufacturing a shaft body, wherein the shaft is a piece and the other side is the second divided piece. 8. The device according to claim 1, wherein a radially inner portion of the radially projecting portion is the first radially extending portion.
Wherein the radially outer portion is the second divided piece. 9. The method according to claim 1, wherein a groove for flowing a heat medium, a coolant, or a lubricating oil is formed on at least one of the joining surfaces of the first and second divided pieces. A method for manufacturing a shaft body. 10. The method of manufacturing a shaft according to claim 9, wherein a flow path for supplying a heat medium, a refrigerant, or a lubricating oil is formed in the groove inside the shaft portion. 11. The groove according to claim 1, wherein a groove for flowing lubricating oil is formed on at least one of the joining surfaces of the first and second divided pieces. A method for manufacturing a shaft, wherein the shaft is connected to an opening for oil blowing formed on an outer peripheral surface of a radially projecting portion. 12. The method according to claim 1, wherein the shaft portion is a shaft portion of a camshaft, and the radially protruding portion is a cam portion of the camshaft. 13. The shaft body according to claim 1, wherein the shaft portion is a shaft portion of a shaft-integrated gear, and the radially projecting portion is a gear portion of the shaft-integrated gear. Production method. 14. The integrated crankshaft according to claim 1, wherein the shaft portion is a shaft portion and a pin portion of an integral crankshaft, and the radially protruding portion is an arm portion of the integral crankshaft. Manufacturing method of the shaft body. 15. A camshaft manufactured by the method according to claim 12. 16. A shaft-integrated gear manufactured by the method according to claim 13. 17. An integral crankshaft manufactured by the method according to claim 14.