JPS6253729B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rotating shaft made of a plurality of metal shaft members and a method for manufacturing the same, and particularly a rotary shaft made of a plurality of metal shaft members suitable for joining together metal shaft members by plastic press-fitting. The present invention relates to a rotating shaft and a method for manufacturing the same.

Most of the rotary shafts and the like of conventional vacuum pumps directly connected to generators are integrally molded from the same material as described in Japanese Patent Application Laid-open No. 114508/1983.

Generally, depending on the required action on the shaft sections, shaft sections made of materials of different hardness or partially mechanically treated are used.
Constructing a single rotating shaft is also desirable from the viewpoint of improving mechanical performance and manufacturability. Moreover, especially in the case of a long shaft, it would be very effective if a single rotating shaft could be manufactured by combining a plurality of shaft parts.

However, since it is difficult to easily obtain the rotational torque (transmission torque) required for a rotating shaft that connects multiple shaft parts, a rotating shaft that is composed of multiple shaft parts is still not put into practical use. do not have.

In addition, between the gear part having a gear on the outer periphery at the end and the rotating shaft main part whose shaft diameter is smaller than that of the gear part connected to this gear part, a step part whose shaft diameter is smaller than that of the rotating shaft main part is provided. The reality is that a rotating shaft consisting of a single shaft in which the bearing part can be compactly stored in the stepped part has not been practically manufactured due to the number of steps required.

An object of the present invention is to configure a rotating shaft using a plurality of metal shaft members, in which the connecting portion between the metal shaft members is made of a plurality of metal shaft members that can provide a mechanically strong connection with high rotational torque. An object of the present invention is to provide a rotating shaft and a method for manufacturing the same.

The present invention is characterized by comprising a first metal shaft member formed with intermittent protrusions that protrude from the reference circle and extend in the longitudinal direction, and a material having lower deformation resistance than the first metal shaft member, The second metal shaft member has a recess for engaging the protrusion of the first metal shaft member, and is plastically press-fitted into the first metal shaft member so that only the protrusion of the first metal shaft member and the vicinity thereof come into close contact with each other. The present invention relates to a rotating shaft made of a plurality of metal shaft members in which a first metal shaft member and a second metal shaft member are connected by force and shearing force, and a method for manufacturing the same.

An embodiment of the present invention will be described based on the drawings.
FIG. 1 shows a vehicle alternator directly connected to a vacuum pump mounted on a diesel engine vehicle to which the rotating shaft of the present invention is applied.

The rotor 1 is mounted on the alternating current generator section 7A of the rotating shaft 7, and includes a magnetic pole 1a, a winding 1b, and a slip ring 1c, and constitutes a rotor magnetic pole. A stator 2 is arranged on the outer periphery of the rotor 1,
It is composed of an armature iron core 2a and a winding 2b, and outputs an alternating current output via a rectifier 8.

2, surrounding the rotor 1 and stator 2.
Brackets 3 and 4 are arranged. The bracket 3 is placed on the pulley side, and the bracket 4 is placed on the side opposite to the pulley. Pulley 5 fixed to rotating shaft 7 is driven by a belt (not shown).

A vacuum pump 6 is arranged on the vacuum pump drive section 7B of the rotating shaft 7. This vacuum pump 6 is directly connected and driven by a rotating shaft 7, and is connected to the engine crankshaft via a pulley 5 via a belt.

The vacuum pump 6 includes a vane 6a and a pump rotor 6.
This is a vane-shaped eccentric pump consisting of b. The vacuum pump 6 is supplied with oil through an oil supply port 6c, sucks air through a suction port 6d, and discharges oil and air through a discharge port 6e.

Further, on the slip ring 1c of the rotor 1, a blank 16 is connected to the rotor 1 of the rotating shaft 7 and the vacuum pump 6.
An oil seal 17 is arranged between the two.

The structure of the rotating shaft 7, which is a feature of the present invention, will be described in detail below. The rotating shaft 7 is press-fitted into the rotor 1, extends long in the axial direction, and is connected to the alternator section 7A.
and a vacuum pump drive section 7B having a serration section 10d.

As shown in FIG. 3, the rotating shaft 7 includes a shaft 20 constituting the alternator section 7A and a shaft 10 constituting the vacuum pump drive section 7B, that is, a press-fit shaft 1.
0 and a press-fitted shaft 20.

Here, shaft 1 is a solid cylindrical press-fit shaft.
0 is made of steel material and is formed in one step by extrusion molding. This shaft 10 includes a first cylindrical portion 10a, a plurality of protrusions 10b, and a second cylindrical portion 10c.
and a serration section 10d. The second cylindrical portion 10c on which the oil seal 17 slides is induction hardened. The diameter of the first cylindrical part 10a is 8 mm, and the second cylindrical part 10c
The diameter is 8.4 mm, which is slightly larger than the diameter of the first cylindrical portion 10a.

Here, the protrusion 10b will be explained in detail.
As shown in FIGS. 6 and 7, the protrusion 11
is formed to protrude from the outer peripheral portion of the first cylindrical portion 10a. In this case, the protrusion 11 of the protrusion 10b is provided on a cylindrical portion having the same diameter as the outer circumference (circular cross section) of the first cylindrical portion 10a. The circle on the outer periphery of the first cylindrical portion 10a from which the protrusion 11 is provided will be referred to as the reference circle of the protrusion 11 or simply the reference circle of the shaft 10.

The protrusions 11 extend linearly in the longitudinal direction on the shaft 10 and are parallel to each other at equal intervals, the number of protrusions n=
There are 8 of them. The specifications of this protrusion 11 are as follows: length l in the longitudinal direction, which is the press-fitting length, = 12 mm, protrusion height h = 0.2 mm, protrusion base length s = 0.4 mm, and protrusion angle θ = 60°.

The cross-sectional shape of the protrusion 11 is bilaterally symmetrical, and the top portion 12 thereof has an arc shape. Also, the protrusion 11
The inlet part forms an inclined plane 13 with an angle γ=30°.

The protrusion 11 forms flat surfaces 14 and 15 on both sides. Further, the second cylindrical portion 10c and the terminal end of the protrusion 11 are continuous. An inclined plane at the tip of the second cylindrical portion 10c is formed between adjacent protrusions 11 at the end portions of the protrusions 11.

In this way, regarding the protrusion 10b, the diameter of the reference circle is 8 mm, and the protrusion height h
= 0.2mm, and the top part 12 is the second cylindrical part 10c.
It is located on the same level as the height (diameter 8.4 mm).

Further, a shaft 2 which is a press-fitted shaft into which the shaft 10 is press-fitted is also provided.
0 has a hole 20a at its end into which the protrusion 10b of the shaft 10 is press-fitted. The diameter D _p of the outer peripheral portion of the shaft 20 is 12 mm, and the diameter D _i of the wall portion 20b formed by the hole 20a of the shaft 20 is 8 mm. Same as diameter.

Here, the diameter D _i of the wall portion 20b of the hole 20a of the shaft 20 is referred to as the reference circle of the shaft 20. In this case, axis 2
The reference circle 20 has the same size as the reference circle of the protrusion 11 of the shaft 10.

The material of the shaft 20 is soft steel, which has a lower deformation resistance (softer material) than the material of the shaft 10.

Next, shaft 10 and shaft 2 having the above configuration
The process of combining 0 will be explained.

First, the shaft 20 is inserted and placed on a shaft mounting table that prevents the shaft 20 from moving in the left-right direction and downward direction.

On the other hand, the shaft 10 is held by a claw of a hydraulic cylinder device. This shaft 10 and the shaft 20 of the mounting table are set so that their centers are aligned in the vertical direction.

The shaft 10 is then moved downward by a hydraulic cylinder device with a pressing force of about 300 to 400 kg. first,
The first cylindrical portion 10a of the shaft 10 is inserted into the hole 20a of the shaft 20. At this time, the first cylindrical portion 10 of the shaft 10
a does not come into contact with the wall 20b of the hole 20a of the shaft 20.

The entrance portion of the protrusion 11 of the shaft 10 is then inserted into the shaft 20. Here, the inclined plane 13 of the protrusion 11 performs its function. That is, since the inclination angle γ is set to 30°, the subsequent protrusion 11 that is subsequently inserted can smoothly come into contact with the wall 20b of the hole 20a of the shaft 20 and come into close contact with it. The smooth guiding action of the inclined plane 13 at the entrance of the protrusion 11 and the fact that the reference circles of the shafts 10 and 20 are the same combine to provide high centripetal accuracy between the shafts 10 and 20.

Furthermore, from the middle of the entrance part of the protrusion 11 of the shaft 10,
Shaft 10 enters into contact with shaft 20. And axis 1
0 moves downward, the entrance portion of the protrusion 11 of the shaft 10 is wedged into the shaft 20 made of a material with low deformation resistance. Finally, the top of the protrusion 11 of the shaft 10 comes into contact with the shaft 20, and from then on the protrusion 11 of the shaft 10 contacts the shaft 2.
It's 0.

The portion of the shaft 20 that is pressurized and pushed outward by the projection 11 of the shaft 10 undergoes plastic deformation as the material around the projection 11 of the shaft 10 flows. In this way, the shaft 10 plastically deforms the shaft 20, and the shaft 10
The protrusion 11 of 0 and its surroundings are press-fitted into the shaft 20 while coming into close contact with the shaft 20.

At this time, the material between adjacent protrusions 11 of the shaft 10 of the shaft 20 is heaped up in a direction in which the diameter increases from the reference circle of the shaft 20, in other words, outward from the reference circle of the protrusions 11 of the shaft 10. . The resulting gap δ between shafts 10 and 20 was approximately 0.02 mm.

It should be noted that the time required for these series of joining processes is approximately 1 second after the shafts 10 and 20 are set to complete the joining operation.

Through the above bonding process, the rotating shaft 7, which is a metal bonding structure of the shaft 10 and the shaft 20 as shown in FIGS. 3 and 4, is completed. A close connection between the shafts 10 and 20 will be considered. As shown in the 50 times enlarged photograph in FIG. 8 and the 100 times enlarged photograph in FIG. 9 showing the state around the joint, the shafts 10 and 20 exhibit a characteristic joint state.

That is, the wall portions 20b of the shaft 10 and the shaft 20 are
The protrusion 11 of the shaft 10 is located at the top 1, excluding the inclined plane 13.
2. Of course, the side surfaces 14 and 15 are in close contact with the reference circle portion 18a around the protrusion 11. The shafts 10 and 20 are separated from each other at a portion of the reference circle portion 18b located between the adjacent protrusions 11, and are not in contact with each other.

To further explain this bonding state using FIG. 10,
The shaft 10 and the shaft 20 are completely in contact with each other at the peripheral portion including the shaft 10 and the protrusion 11, but in the middle part between the adjacent projections 11, the reference circle portion 18b of the shaft 10
and the shaft 20 are spaced apart from each other.

The distance δ between the shafts 10 and 20 is approximately 0.02 mm,
Further, the distance h between the top 12 of the protrusion 11 of the shaft 10 and the shaft 20 is approximately 0.2 mm.

The peculiar bonding state around the coupling part of the rotating shaft 7, which is such a coupling structure, is that the shaft 10 has a higher deformation resistance (harder) than the shaft 20, so even if it is press-fitted into the shaft 20, the external shape does not change. It can be said that this occurs as a result of the shaft 20 having low deformation resistance (soft) undergoing plastic deformation, whereas it does not.

In the rotating shaft 7, which is the above-mentioned joint structure, as shown in FIG.
The inside of the close contact part of the shaft 20 that is in close contact with the shaft 10 around 1 is locally plastically deformed by the protrusion 11, and the internal pressure becomes high.In other words, an elastic stress larger than the yield stress of the close contact part is generated, and it tends to spread inside. A force acts on it. Therefore, a tension force P ₁ is acting inside the close contact portion. This tension force P ₁ is caused by the projection 11 of the shaft 10
The top portion 12, side surface 14, side surface 15, and portion 18a that is in contact with the shaft 20 at the reference circle of the shaft 10 are firmly pressed and expanded.

In this way, in this embodiment, the alternating current generator for a diesel engine is constructed by integrating the parts into a shaft, and then assembling various parts into this rotating shaft.

According to the above embodiment of the present invention, the following effects are achieved.

(1) The shaft 10 is formed with eight intermittent protrusions 11 that protrude from the reference circle and extend in the longitudinal direction.
A shaft 2 having a hole 20a of the same size as the reference circle of
0 and plastically deformed the shaft 20 to obtain a rotating shaft 7 which is a mechanically strong coupling structure between the shafts 10 and 20.

As described above, according to the present invention, it is possible to obtain the rotating shaft 7 which has a rotational torque as high as 43 kg·m, which is more than three times as high as that of the knurled press-fitting method, and this rotational torque is equivalent to the rotational torque obtained by fitting connection. or exceed this value.

(2) The shaft 10 and the shaft 20 are the top 12, side surface 14, and side surface 15 of the protrusion 11 of the shaft 10, and the portion 18a that is in close contact with the shaft 20 on the reference circle of the shaft 10,
A tension force P ₁ acts inside the close contact part of the shaft 20,
Since the close contact part of the shaft 10 is firmly expanded, the necessary tension force P ₁ can be applied to the shaft 10.
A rotating shaft 7, which is a coupling structure having a mechanically stable and strong bonding force between the rotary shaft 20 and the shaft 20, was obtained.

(3) Since the inclination angle γ of the inclined plane 13 of the protrusion 11 of the shaft 10 is 30°, the subsequent protrusion 1
1 is smoothly connected to the wall 20b of the hole 20a of the shaft 20.
I was able to come in close contact with it.

Furthermore, the centripetal accuracy between the shafts 10 and 20 could be improved. This centripetal precision has been improved, so
A rotary shaft 7 with no backlash between the shafts 10 and 20 and with increased durability was obtained.

(4) The reference circle of the shaft 10 and the reference circle of the shaft 20 are the same, and the accuracy of this reference circle is also high, so the centripetal precision is maintained high between the reference circles, so the reference circle of the shaft 10 is the same.
A rotating shaft 7, which is a joint structure with high centripetal accuracy between the shaft 20 and the shaft 20, was obtained.

(5) Since the shaft 10 is made of a material with higher deformation resistance (harder material) than the shaft 20, the shaft 10 is not distorted by pressurization or plastic flow, and high precision is maintained.

(6) Since the rotating shaft 7, which is a joint structure between the shafts 10 and 20, has the reference circle described above provided on both shafts, bending of the shaft does not occur and assembly accuracy can be improved. .

(7) Since the shaft 10, which is composed of the first cylindrical part 10a, the projection part 10b, the second cylindrical part 10c, and the serration part 10d, is finished in one step of plastic working, the material yield is good and the productivity is high. Improved.

(8) Although induction hardening is applied to the second cylindrical portion 10c of the shaft 10 on which the oil seal 17 slides, since the axial length of the shaft 10 is short, almost no bending occurs due to hardening.

(9) Since the rotating shaft 7 is constructed by combining two shafts, the shaft 20 and the shaft 10, a high material yield and high productivity can be obtained.

Next, in order to find the optimal rotating shaft and coupling method for press-fit coupling by plastic deformation between shafts, the inventors investigated the relationship between shaft members and their optimal specifications from various angles. . The results of this study will be explained below.

First, we will discuss the test materials. As shown in FIGS. 11 and 12, the shaft A, which is a press-fitting member, was made of steel. Further, the shaft B, which is a press-fitted member, is made of mild steel.

On the axis A, n protrusions p are provided at equal intervals on a reference circle having a diameter d _a . As shown in Fig. 12, the specifications of the protrusion p are as follows: the press-fit length is l _a , the protrusion height is h _a , the protrusion angle is θ _a , and the protrusion base length is s _a
It is expressed as Further, as shown in FIG. 11, the outer diameter of the shaft B is D _p and the inner diameter is D _i .

First, the influence of the size of the protrusion angle θ _a of the protrusion p on the axis A was studied.

That is, an experiment regarding the magnitude of the press force P required to press fit the shaft A to the shaft B, and the magnitude of the rotational torque (transmission torque) T possessed by the rotating shaft that is the coupling structure of the shafts A and B. The results were as shown in FIG.

In this case, the reference circle diameter d _a of axis A was 8 mm, the outer diameter D _a of disk B was 12 mm, and the inner diameter D _i was 8 mm. The specifications of the protrusions p were as follows: number of protrusions n = 8, press-fit length l _a = 12 mm, protrusion height h _a = 0.2 mm, and protrusion base length s _a = 0.4 mm.

In FIG. 13, the curve X ₁ shows the magnitude of the rotational torque T, and the curve X ₂ shows the magnitude of the pressing force P with respect to the rate of change in the magnitude of the protrusion angle θ _a of the protrusion p.

From the results of this experiment, it has been found that the protrusion angle θ _a of the protrusion p provided on the reference circle of the axis A is preferably in the range of about 40 to 70 degrees.

Furthermore, an experiment was conducted to examine the influence of the number n of protrusions p provided on the axis A.

FIG. 14 shows the magnitude of the rotational torque T of the rotating shaft, which is a joint structure of the shafts A and B, depending on the number n of projections p of the shaft A.

That is, in FIG. 14, curve _X3 represents the magnitude of rotational torque T.

In this case, the reference circle diameter d _a of axis A = 8 mm, axis B
The outer diameter D _p =12 mm and the inner diameter D _i =8 mm were selected. Also, the specifications of the protrusion p are press-fit length l _a = 12 mm,
The protrusion height h _a =0.2 mm, the protrusion angle θ _a =60°, and the protrusion base length s _a =0.4 mm were adopted.

According to the results of this experiment, when the number n of protrusions p was 16 or more, the shaft A was damaged or deformed and the rotational torque T became constant, making it unusable.

From this experimental result, considering the magnitude of the rotational torque T obtained, the number of protrusions n of the protrusions p
= 8 to 16 (integer) was found to be an appropriate numerical range. In this case, when considering the ratio of the number n of protrusions p to the standard circular diameter d _a (unit: mm) of the axis A, a range of 2/3 to 11/3 is preferable.

In addition, the influence of the protrusion height h _a of the protrusion p provided on the reference circle of the axis A was investigated.

In FIG. 15, a curve X ₄ indicates the magnitude of the rotational torque T possessed by the rotating shaft, which is a joint structure of the shafts A and B, depending on the protrusion height _ha .

In this case, the reference circle diameter d _a of axis A = 8 mm, axis B
The outer diameter D _p =12 mm and the inner diameter D _i =8 mm were selected. In addition, the specifications of the protrusion p are as follows: number of protrusions n = 8, press-fit length l _a = 12 mm, protrusion angle θ _a = 60°, and protrusion base length s _a is s _a = 1.5 h _a and protrusion height. The parameter h _a was adopted.

According to this experimental result, the protrusion height h _a of the protrusion p
It has been found that if the size is 0.55 mm or more, the shaft A will be damaged or deformed and cannot be put to practical use.

From the results of this experiment, it was found that considering the magnitude of the rotational torque T obtained, the protrusion height h _a is preferably in the range of h _a =0.15 to 0.55 mm.

Furthermore, as shown in FIG. 14, it has been found that the protrusion height h _a of the protrusion p has a great effect on the magnitude of the rotational torque T. Then, the protrusion height _ha of the protrusion p can be determined depending on the required rotational torque T.

In addition, when the protrusion height h _a of protrusion p is 0.55 mm,
The distance δ between axis A and axis B was approximately 0.04 mm.

Further, considering the above results, it is preferable that the protrusion base length s _a of the protrusion p is in the range of 1.3 to 3 times the protrusion height h _a .

Taking all the above study results into consideration, it is recommended that the following rotation shaft be selected as the optimal joint structure.

In other words, regarding the specifications of the protrusions provided on a shaft member with high deformation resistance, considering the amount of rotational torque obtained, the appropriate range for the number of protrusions is 8 to 16, which is the standard for a shaft member with high deformation resistance. In terms of the ratio of circular diameters (unit: mm), a range of 2/3 to 11/3 is preferable.

In addition, the protrusion angle of the protrusion of the shaft member is approximately
A range of 40 to 70° is preferred.

Furthermore, considering the magnitude of rotational torque, the height of the protrusion is preferably in the range of 0.15 to 0.55 mm, and it has also been found that this height of the protrusion has a large effect on the magnitude of the rotational torque that can be obtained.

In addition, the protrusion base length of the protrusion is 1.3 to 3 of the protrusion height.
A double range is preferred.

In addition, when we examined the size of the reference circle of the shaft member that forms the protrusion and the reference circle of the shaft member that undergoes plastic deformation, we found that the reference circle of the latter shaft member is the same as the reference circle of the former shaft member. , or the reference circle needs to be slightly larger.

According to experiments, the gap between the reference circle of the latter shaft member and the reference circle of the former shaft member having a protrusion is 0 to 0.
A size of 0.1 mm was found to be preferable.

Furthermore, if the inlet of the protrusion of the shaft member having a protrusion is made into an inclined plane and the angle of inclination is approximately 15 to 45 degrees, the shaft member can be smoothly inserted into the press-fitted shaft member.

In the present invention, the material of the first shaft member forming the protrusion is required to be harder and have greater rigidity than the material of the second shaft member which undergoes plastic deformation. This is because the first shaft member must be sufficiently rigid without being deformed while the second shaft member is pressurized and undergoes plastic flow.

In other words, the second shaft member must be made of a material that has less deformation resistance (softer material) than the first shaft member. For example, when the first shaft member is made of steel, the second shaft member is preferably made of aluminum, brass, copper, mild steel, or the like.

Furthermore, regarding the relationship between the first shaft member in which a protrusion is formed and the second shaft member that undergoes plastic deformation, an example in which the protrusion protrudes outward toward the first shaft member has been described in the embodiment.

However, a plurality of protrusions extending inward are formed on the wall of the hole of the first shaft member, and a second shaft member having a circular cross section, for example, is coupled to the first shaft member. Of course, it is also good.

In this case, it is necessary to use a material for the first shaft member that has higher deformation resistance than the material for the second shaft member. The size and number of the protrusions and the selection of reference circles for the first metal member and the second metal member may be determined as appropriate with reference to the embodiments described above.

Other embodiments of the present invention will be explained based on the drawings.
FIG. 16 shows the rotary shaft of the present invention applied as a rotary shaft of a general-purpose induction motor of 200 to 300 W.

In the figure, a rotor 41 built into a motor 40 body is mounted on a rotating shaft 30, and a rotor 41 is installed on a rotating shaft 30.
A stator 42 is arranged on the outer periphery of the motor 1 . Brackets 43, 44 and a cylindrical housing 4 surround the rotor 41 and stator 42.
5 is provided. The motor body 40 is the base 4
6, and the rotating shaft 30 is supported by bearings 47 and 48 provided on both sides.

Here, the rotating shaft 30 includes a shaft 60 press-fitted into the rotor 41 and a hole 6 provided at the end of the shaft 60.
Press fit into 0a. two shafts 60 with shaft 50,
It consists of 50.

As shown in FIG. 17, the shaft 50, which is made of a material with higher deformation resistance than the shaft 60, has a first cylindrical portion 50a, a protrusion 50b, a second cylindrical portion 50c, and a third cylindrical portion 50c.
It is composed of a cylindrical portion 50d and a threaded portion 50e. The protrusion 50b includes a plurality of protrusions 5.
It consists of 1.

Here, the diameter of the reference circle forming the projections 51 of the shaft 50 is 8 mm, and eight projections 51 are provided on the reference circle. The specifications of the protrusion 51 are: press-fit length l = 12 mm;
The protrusion height h=0.2 mm, the protrusion base length s=0.4 mm, and the protrusion angle θ=60°.

Further, the outer diameter D _p of the shaft 60 is 12 mm, and the diameter D _i of the hole 60a of the shaft 60 is 8 mm.

In this case, the shaft 5 is made of a material with high deformation resistance.
0 is the hole 6 of the shaft 60 made of a material with low deformation resistance.
0a, the shaft 60 is plastically deformed and press-fitted.

Therefore, in this embodiment as well, a tension force is applied to the close contact portion between the shaft 50 and the shaft 60, and the rotating shaft 30 is obtained as a mechanically stable and strong joint structure under a large rotational torque. .

Furthermore, another embodiment of the present invention will be described based on FIG. 18. Here, the rotating shaft 70 is a shaft 90 (diameter
16 mm) and a hole 90a provided at the end of this shaft 90.
Shaft 80 (diameter 20 mm) press-fitted into (diameter 8 mm)
and two shafts 90, 80 having two different diameters.

Furthermore, the shaft 80 is provided with a protrusion 81 . The protrusions 81 extend linearly in the longitudinal direction on the shaft 80 and are parallel to each other at equal intervals.
mm), the number of protrusions n=8 is provided on the top. The specifications of this protrusion 11 are: press-fit length l = 12 mm, protrusion height h
= 0.2mm, protrusion base length s = 0.4mm and protrusion angle θ
= 60°.

Further, between the shafts 80 and 90, a bearing portion 82 having a width of 8 mm is housed in a stepped portion formed by the shafts 80 and 90.

In this case, the shaft 8 is made of a material with high deformation resistance.
0 is the hole 9 of the shaft 90 made of a material with low deformation resistance.
0a, the shaft 90 is plastically deformed and press-fitted.

Therefore, in this embodiment as well, a tension force acts on the close contact portion between the shafts 80 and 90, and the rotating shaft 70, which is a mechanically stable and strong joint structure under large rotational torque, can be obtained. Ta.

Further, a shaft 80 and a shaft 90 each having a different diameter.
The rotary shaft 70 having a configuration in which the bearing portion 82 is housed in a stepped portion cannot be obtained by conventional techniques, and it is also possible to realize the rotary shaft 70 with such a large change in diameter by the above-described implementation of the present invention. This is a big effect as an example.

In the embodiment of the present invention, two metal shafts are connected together to form a rotating shaft, but three or more metal shafts may be connected to each other to form a rotating shaft.

Moreover, although the engaging recess of the press-fitted member has been described as a bottomed hole, it goes without saying that a through hole may be used depending on the case.

As described above, according to the present invention, the first metal shaft member is made of a material having smaller deformation resistance than the first metal shaft member, and has intermittent protrusions that protrude from the reference circle and extend in the longitudinal direction. A second metal shaft member having a recess for engaging the protrusion of the first metal shaft member in the part thereof, and into which the first metal shaft member is plastically press-fitted so that only the protrusion of the first metal shaft member and its vicinity are in close contact with each other; Since the first metal shaft member and the second metal shaft member are connected by tension force and shearing force, the joint portion of the metal shafts has a plurality of mechanically strong connections with high rotational torque. A rotating shaft made of a metal shaft member and a method for manufacturing the same were obtained.

[Brief explanation of the drawing]

Fig. 1 is a partial cross-sectional view of an alternator for a diesel engine vehicle to which a rotating shaft is applied, showing an embodiment of the present invention, and Fig. 2 is a partial cross-sectional view of an alternator for a diesel engine vehicle shown in Fig. 1. A side view of only the vacuum pump section seen from the right side, Figure 3 is a plan view of the rotating shaft of the alternator for diesel engine vehicles, and Figure 4 is a view of the connecting part of the rotating shaft for diesel engine vehicles shown in Figure 3. FIG. 5 is an enlarged partial sectional view, FIG. 5 is a perspective view of a rotating shaft for driving a vacuum pump for a diesel engine vehicle, FIG. 6 is an enlarged perspective view of a protrusion of the rotating shaft shown in FIG. 5, and FIG. Figure 8 is a 50x magnified micrograph showing the connection state around the protrusion of a rotating shaft for a diesel engine vehicle, and Figure 9 is a 100x magnification showing the connection state around the protrusion. A microscopic photograph, Fig. 10 is an enlarged explanatory view showing the connection state of the rotating shaft for a diesel engine vehicle, and Fig. 11 is a partial cross section of a test shaft for determining the specifications of the rotating shaft for a diesel engine vehicle of the present invention. An explanatory diagram, FIG. 12 is a schematic explanatory diagram of a shaft that is a press-fitting member, and FIG. 13 is a diagram showing the magnitude of the rotational torque T and the magnitude of the press force P when the protrusion angle θ of the shaft that is a press-fitting member is used as a parameter. Figure 14 is a comparison diagram of the magnitude of rotational torque T when the number n of protrusions on the shaft that is a press-fit member is used as a parameter, and Figure 15 is a diagram that shows the height h of the protrusion on the shaft that is a press-fit member. 16 is a partial sectional view of a general-purpose induction motor showing a rotating shaft showing another embodiment of the present invention, and FIG.
A perspective view of a shaft that is a press-fit member among the rotating shafts shown in the figure, and FIG. 18 is a sectional view of the rotating shaft showing another embodiment of the present invention. 7... Rotating shaft, 10... Shaft, 10b... Protrusion, 20... Shaft, 20a... Hole, 30... Rotating shaft, 50... Shaft, 50b... Protrusion, 60...
Shaft, 60a...hole, 70...shaft, 80...shaft, 8
1...protrusion, 90...shaft, 90b...hole.

Claims (1)

[Scope of Claims] 1. A circular first metal shaft member formed with a protrusion that projects in the radial direction from the reference circle and extends in the longitudinal direction, and is made of a material that has less deformation resistance than the first metal shaft member, In the metal bonding structure comprising a second metal shaft member that is press-fitted into the first metal shaft member and closely contacts the protrusion of the first metal shaft member and its vicinity, the first metal shaft member The protrusion angle θ on the outer periphery is 40 to 70°, the protrusion height h is 0.15 to 0.55 mm, the protrusion base length s is (1.3 to 3) h, and the number of protrusions is (2/3 to 11/
3) D protrusions (where D is the diameter of the first metal shaft member and the number n of protrusions is an integer) are intermittently arranged and press-fitted into the engagement hole of the second metal shaft member, and the It is characterized by tightly adhering to the reference circle portion around the protrusion and its base portion, and facing the reference circle of the first metal shaft member corresponding to between the protrusions with a small gap. A rotating shaft consisting of multiple metal shaft members. 2. In what is stated in claim 1,
The inclination angle at the entrance of the first metal shaft member protrusion is 15~
A rotating shaft made of a plurality of metal wire members, characterized by forming a 45° inclined plane. 3. A first metal shaft member having a reference circle on its outer periphery, and a second metal shaft member having an inner wall having a reference circle of approximately the same size as the reference circle of the first metal shaft member, The member and the second metal shaft member are made of materials with different deformation resistances, and in the method of joining the first metal shaft member and the second metal shaft member, the first metal shaft member with high deformation resistance is It protrudes from the outer periphery and has an inclined entrance, with a protrusion angle θ of 40
~70°, protrusion height h is 0.15 to 0.55 mm, protrusion base length s is (1.3 to 3) h, and number of protrusions is (2/3 to 11/3) D
protrusions extending in the longitudinal direction of the second metal shaft member are formed intermittently in the circumferential direction, and the protrusions of this metal shaft member are press-fitted into holes provided in the second metal shaft member, and the holes are inserted into the holes provided in the second metal shaft member. The first metal shaft member and the second metal shaft member are locally plastically deformed around the periphery so that only the protrusion and its vicinity are brought into close contact with each other, and the tension force generated around the protrusion connects the first metal shaft member and the second metal shaft member. A method for manufacturing a rotating shaft comprising a plurality of metal shaft members.