JPS5938861B2 - Manufacturing method of joint shaft - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for manufacturing a joint shaft in which a rotor, a commutator, a fan, etc. are firmly fitted together by forming a coining on the outer periphery of the shaft using a mold to form a raised part. It is related to.

A spline shaft is a shaft to which the rotor can be integrally connected, but it has the disadvantage that the shaft bends significantly due to the heavy press-fitting load.

On the other hand, a method of providing coining using a mold instead of a spline is also known.

However, in conventional coining formation methods, the height of the coined ridge is low and the angle β is large, resulting in low torque strength at the joint and large axial bending when forming the coined impression. was there.

An object of the present invention is to provide a method for manufacturing a coupling shaft that has high torque strength when coupled to a rotor, etc., and has less shaft bending when forming impression marks.

A feature of the present invention is that when rolling down a mold, a line segment connecting the center of the shaft and the position where the blade of the mold first touches the outer periphery of the shaft is a line that is perpendicular to the rolling direction of the mold and passes through the center of the shaft. The angle θd made with the minute is 1
The reason is that the angle is between 2° and 25°.

An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 1, a rotating shaft 10 is made of a material such as SCM3°545C, and a plurality of coinings 12 are provided on its outer periphery.

As shown in FIG. 2, the coining 12 consists of a raised edge 13 that is higher than the outer peripheral surface 11 of the rotating shaft 10 (diameter Do) and a groove 14 that is lower.

FIG. 3 shows the manufacturing method of coinage 12.

The upper and lower molds 50, 60 each have a pair of blade portions 51, 52, 61°62 through a gap B=DocO3θd (θd will be described later) that is slightly narrower than the diameter Do of the rotating shaft 10.

A rotating shaft 10 is placed between the blade parts, and a load P is applied in the vertical direction.

As a result, coining marks 12 are formed at four locations.

An appropriate number of coining liquids can be provided by rotating the rotating shaft by appropriate angles and coining with a mold.

4th. Figure 5 shows a detailed cross section of the coined area.

The position where the blade portions 5L61 of the molds 50, 60 contact the outer periphery of the rotary shaft 10, that is, the position where the blade portion 51 first contacts the outer periphery of the rotary shaft 10 when the mold is rolled down is designated as 81. S2, and a horizontal line passing through the center O of the rotation axis (direction perpendicular to the rolling direction of the mold) is OC.

There is a desirable range for the angle θd between the line segment OC and the line segment 081 (or S2) from the viewpoint of the bending of the rotation axis during coining impression formation and the torque strength after coupling.

First, the relationship between the torsional torque strength of the coined area and θd is as shown in FIG.

In the range where θd is less than lO°, the load P applied to the mold is
The direction of action of contact point S1. It is close to the tangential direction of the rotation axis in S2, and slippage occurs at the contact portion, which is the same as cutting, making it difficult to form a coining liquid.

On the other hand, when θd is large, the raised edge height ΔH of the coining liquid is low and the raised edge angle β is large, resulting in a decrease in bonding strength when a rotor or the like is press-fitted onto the rotating shaft.

As is clear from FIG. 6, high torque is obtained when θd is in the range of 2° to 25°, and especially high torque is obtained when θd is in the range of 15' to 20°.

Further, the relationship between θd and the curvature of the rotating shaft is as shown in FIG.

(The material of the rotating shaft is SCM3, D.-20rratt, shaft length L-2707/Ln) In this case, θd is 12
The amount of bending is reduced in the range of ° to 25 °.

It is thought that the relationship between θd, torque, and shaft bending is related to the direction of action of the principal stress during pressurization by the mold.

That is, as shown in FIGS. 8 and 9, the direction of action of the principal stress σ0 due to the pressing force P changes as θd becomes smaller.

FIG. 8 shows the case of θd-45°, where the transmission range (58°) of the principal stress σ0 within the rotating shaft is wide, and a part of this stress acts to bend the rotating shaft.

Furthermore, since the stress is widely distributed within the rotating shaft, it does not effectively affect the formation of raised edges.

On the other hand, what is shown in FIG. 9 is a case where θd=20°, and the acting direction of the principal stress σ0 due to the pressing force P is concentrated at the end of the rotating shaft and effectively contributes to the formation of the protrusion.

In addition, there is little stress acting in the direction of bending the rotating shaft, so there is almost no bending of the shaft.

When the material of the rotating shaft is SCM3 and the diameter Do is 20 mm, when a load of 9 tons is applied to the mold at the position θd-45° to form a coining liquid, the height ΔH of the raised edge is O, l.
mrIL, the angle β was 110°, but under the same conditions, when θd-20°, ΔH was 0.2 mm, and the angle β was 110°.
became 90°.

To increase the torque strength of the joint, the raised edge height ΔH
is 0.15mm to 0.40mm, angle β is 60° to 1
It is desirable that the angle be within the range of 00°.

When θd is in the range of 12° to 25°, a raised edge satisfying the above conditions can be obtained.

The number of coining liquids is practically 16 or less, preferably 8.
It is preferable to set the number to 12.

Next, the relationship between the edge angle α of the mold 50.60 and the mold life is as shown in FIG.

The edge angle α is practically 95° to 120°, preferably 1
The angle is preferably 00-110°.

If α is small, stress concentration will be large and chipping will occur, resulting in a shortened mold life.

Furthermore, if α is large, seizure is likely to occur and the life of the mold is shortened.

Furthermore, the bending after axial press-fitting by the method of the present invention and the conventionally known knurling press-fitting method is as shown in FIG.

In knurling press-fitting method A, the press-fitting load is approximately twice as much as in method B of the present invention, and furthermore, since there is no base circle to obtain the centripetal force during press-fitting, an uneven load occurs during press-fitting, and due to the interaction The bending of the shaft increases.

FIG. 12 shows a longitudinal cross section of a rotating field alternating current generator for an automobile, which is an application example of the present invention.

In the figure, 81 and 82 are a pair of housings, and the stator core 83 is held between them.

Reference numeral 84 denotes a rotating shaft, which is supported by bearings 85 and 86 in the housings 81 and 82.

A hollow yoke 8 constituting a core member is attached to the rotating shaft 84.
7 and rotor cores 88 and 89 are fixed.

The outer circumferential portion of the rotor core 88.89 has claws 881.89.
1 are formed so that they are inserted into each other.

The material of the rotor cores 88 and 89 needs to have lower deformation resistance than the material of the rotating shaft 84.

In the embodiment, the rotating shaft 84 is 545C, and both the rotor core and yoke are made of low carbon steel.

A field winding 90 is wound around the yoke 87, and power is supplied from the outside via a slip ring 91 and a brush 92.

ψ indicates magnetic flux. There is a coining liquid 95 formed by the method of the present invention on the outer periphery of the rotating shaft 84, which connects the rotating shaft, the yoke 87, and the rotor cores 88, 89, and ensures rotational torque and axial withdrawal resistance.

Further, the rotating shaft and the slip ring holding cylinder 93 are connected by a coining liquid 96.

The diameter Do of the rotating shaft 84, the yoke 87, the rotor core 88.
89 and the inner diameter D1 of the hollow portion of the slip ring holding cylinder are preferably in a loose fit or a stop fit, but may be a tight fit depending on the application.

By employing the coupling method of the present invention, bending of the rotating shaft 84 can be reduced, and a generator with high performance and reliability can therefore be obtained.

FIG. 13 shows an example in which the present invention is applied to a starting motor for an automobile.

The laminated rotor core 202 of the electric motor 201 is coated with a coining liquid 203.
It is fixed to a rotating shaft 204 having a diameter.

The rotation of the rotating shaft 204 is controlled by the sleeve 205 and the clutch 20.
6 to a pinion 207, which meshes with a ring gear 208.

In addition, the commitake 211 of the electric motor 201 and the rotating shaft 20
A coining liquid can also be used for bonding with 4.

As described above, according to the method of the present invention, in the method of manufacturing a rotating shaft using a coining liquid, bending of the rotating shaft can be reduced and the life of the mold can be extended.

[Brief explanation of drawings]

Fig. 1 is a perspective view of a coupling shaft according to an embodiment of the present invention;
The figure is a sectional view of the main part of the coupling shaft in Figure 1, and Figures 3 to 5 are
The method of manufacturing the coupling shaft is shown in FIG. 3, which shows the relationship between the mold and the rotating shaft, and FIGS. 4 and 5, which are sectional views of the main parts showing details of the coining liquid. Figure 6 shows the relationship between θd and torque, Figure 7 shows the relationship between θd and the amount of bending of the rotating shaft, and Figures 8 and 9 show the relationship between θd -45° and 20°, respectively. It is a figure explaining the distribution situation of principal stress. FIG. 10 is a diagram showing the relationship between the edge angle α of the mold and the life of the mold, and FIG. 11 is a diagram comparing the amount of bending after axial press-fitting by the conventionally known knurling press-fitting method and the method of the present invention. FIG. 12 is a diagram showing a longitudinal section of a rotating field alternating current generator for an automobile to which the present invention is applied. FIG. 13 is a diagram showing a longitudinal section of an automobile starting motor to which the present invention is applied. 10...Rotating shaft, 12...Coining liquid, 5
0.60...Mold. 118-

Claims (1)

[Claims] 1. In a method for manufacturing a joint shaft in which several joint coinings are formed in the longitudinal direction on the outer circumference of the shaft using a mold, when the mold is rolled down, the blade of the mold first A joint shaft characterized in that the angle θd between a line segment connecting a position in contact with the outer circumference of the shaft and the shaft center with a line segment perpendicular to the rolling direction of the mold and passing through the shaft center is in the range of 12° to 25°. Production method. 2. A method for manufacturing a joint shaft in which several joint coinings are formed in the longitudinal direction on the outer circumference of the shaft using a mold, in which the cutting edge angle α of the mold is set to 100° to 115°, and the mold is rolled down. At this time, the angle θd between the line segment connecting the position where the mold blade first touches the shaft outer circumference and the shaft center and the line segment passing through the shaft center at an angle perpendicular to the rolling direction of the mold is 12° to 25°. A method for manufacturing a joint shaft, characterized in that: