JPS594566B2 - Jikuketsugousouchi - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a shaft coupling device, particularly a concave receiving portion having an n-convex polygonal shape in cross section (where n is an integer of 3 or more - hereinafter referred to as a convex polygonal shape or polygonal shape in cross-section). In a shaft coupling device in which a driving force is transmitted by fitting a fitting part having a convex part with a shape corresponding to the concave receiving part of the polygonal shape to the receiving part, there is provided a shaft coupling device that is easily attached to the end face of the receiving part. The present invention relates to a shaft coupling device in which a fitting portion is easily and reliably fitted into a receiving portion by providing a cutout surface having a unique shape.

2. Description of the Related Art For example, electric drills have been known that utilize the rotational output of a motor driven by a built-in battery.

In general, this type of electric drill reduces the rotational speed from the drill and the motor provided at the tip of the main body case in which the battery for driving the motor and the motor are housed to achieve the desired rotational output. a shaft coupling device configured to transmit the motor output to the deceleration means when the attachment is attached to the main body case. Prepared.

This type of shaft coupling device conventionally includes a receiving part that is fitted onto a motor rotating shaft and has a recessed receiving part with a cross section of, for example, a regular hexagonal shape, and a shaft that is connected to the attachment side and has a regular hexagonal cross section. The fitting part has a regular hexagonal convex part that corresponds to the concave receiving part, and at the same time when the main body case and the attachment case are fitted, the receiving part and the fitting part are properly connected in the shaft coupling device. Must be mated.

However, in general, fitting can be achieved only when the shape of the end surface of the receiving portion and the shape of the end surface of the fitting portion substantially match and face each other.

Therefore, when the attachment case is attached to the main body case, the fitting operation becomes even more troublesome if the relative positional relationship between the receiving part and the fitting part cannot be seen.

The present invention aims to solve the above-mentioned problems, and provides a simple shape to the end face of the receiving portion, thereby facilitating the fitting operation of the fitting portion to the receiving portion.

This will be explained below with reference to the drawings. Fig. 1 is a sectional view of an electric drill using a drill as an attachment as an example of an electric device to which the present invention is applied, Fig. 2 is a plan sectional view showing the main part of the electric drill, and Fig. 3 is the main body. FIG. 4 is a front view of the main body case, FIG. 5 is a perspective view of a conventional fitting part, and FIGS. 6A and 6B are explanatory diagrams for explaining the relationship between the case and the attachment.

C is an example of a receiving part corresponding to the fitting part, FIG. 7AB is an explanatory diagram for explaining the relationship between the fitting part and the receiving part,
FIGS. 8A, B, and C show a receiving part in a shaft coupling device according to an embodiment of the present invention; FIGS. 9A, B, and C show a fitting part fitted into the receiving part; FIGS. 10A, B, and 11A and 11B are explanatory diagrams showing the relationship between the receiving part and the fitting part in the shaft coupling device,
Figure 2A.

B and C are receiving parts in another embodiment of the present invention, and FIGS. 13A and B and FIGS. 14A and B are explanatory diagrams for explaining the relationship between the receiving part and the fitting part', respectively. It shows.

In FIGS. 1 to 4, an electric drill device 1 is composed of a drive section 1a and an output section 1b, and the drive section 1a is driven by batteries 3, 3 and can rotate in forward and reverse directions. a motor 4, a pushbutton switch 5 for switch control and forward/reverse rotation control of the motor 4, and the battery 3.
. It is equipped with an attachment case 8.

When pushbutton switch 5 is pressed, batteries 3, 3 and motor 4
For example, a closed circuit is formed with the push button switch 5.
When the front part 5a side of the motor 4 is pressed, the motor 4 is rotated in the forward direction, whereas when the rear part 5b side is pressed, the motor 4 is rotated in the reverse direction.

The rotational force of the motor 4, that is, the motor shaft 60
The rotational force is transmitted to the deceleration means 9 through a shaft coupling device consisting of a receiving part 7 fitted to the motor shaft 6 and a fitting part 10 fitted to the receiving part 7, The rotational force decelerated by the deceleration means 9 is supplied to the drill part 12 through the output shaft 11 of the deceleration means 9, and the drill part 12 is rotationally driven.

There is a gap between the inner circumferential surface of the main body case 2 on the output part 1b' side and the outer circumferential surface of the receiving part 7 in an opening formed in the main body case 2, as shown in FIGS. 2 and 3. The first projections 13a, 13a and the second projection 13b
, 'f3b' is elastically held.

Further, an annular groove 8a as shown in FIG.
When the above-mentioned annular groove 8 is fitted into the main body case 2,
The first projections 13a, 13 of the elastic material body 13 are shown in a.
A is fitted so that both cases are fitted together.

The operation of fitting the output part 1b to the drive part 1a to form the electric drill device 1 is shown in FIG.
The second protrusion 13b of the elastic material body 13 provided on the a side
, 13b in the directions of arrows P and P in the figure, the attachment case 8 is moved relative to the main body case 2 as indicated by arrow A in the figure.

In this case, when the pressing force as described above is applied, the first Q projections 13a, 13a of the elastic material body 13 move in the same manner as the second projections 13b, 13b move in the direction of the center axis of the device due to the pressing force. is moved in the direction of the center axis of the device.

That is, the first protrusion 13a. The distance of 13a from the center axis of the device is reduced by the pressing force as described above.

After the fitting part 10 is inserted into the receiving part 1q and the recessed receiving part 1a, the attachment case 8 is further moved in the direction of arrow A in the figure so that the annular groove 8a of the attachment case 8 is inserted into the elastic material body 13. so as to reach a position facing the first protrusions 13a, 13a.

In this state, the second protrusion 13b as described above
, 13b, the first projection 13a.

13a and the second protrusion 13b, 13b both elastically return to their original states and become the first protrusion 13a.

13a is fitted into the annular groove 8a, so that the driving part 1a and the output part 1b can be fitted together as shown in FIG.

In this way, the fitting part 10 and the receiving part 7 are fitted together before the driving part 1a and the output part 1b are fitted together.

In other words, if the relative angular positional relationship between the fitting part 10 and the receiving part 7 is not such that the fitting part 10 can be inserted into the recessed receiving part 7a of the receiving part 7, the driving part 1a and output section 1
A fit with b cannot be obtained.

5 and 6A show perspective views of a fitting part and a receiving part in a conventionally known shaft coupling device, and FIG. 6B is a plan view of the receiving part shown in FIG. 6A, and FIG. Figure C is Figure 6B
A cross-sectional view of the receiving portion taken along the line xx' shown in the figure is shown.

In FIGS. 5 and 6 A, B, and C, the fitting portion 14 has a convex portion 15 at the tip, and the convex portion 15 has a regular hexagonal apex B1 and B6 at the tip when viewed from the longitudinal direction. The surface 15a is formed with a side end surface 15b which is trapezoidal when viewed from the side surface formed by the vertices B1 to B6 and the vertices B1 to B10 shown in the drawing.

On the other hand, the receiving part 16 has a concave receiving part 17 at its tip into which the convex part 15 of the fitting part 14 is fitted, and the concave receiving part 11 has the same shape and dimensions as the convex part 15 of the fitting part 14. is formed.

That is, the side end surface 17a of the recessed receiving portion 17 formed by the vertices A1 to A6 and the vertices A'1 to A'6 shown in FIGS. 6A, B, and C has the same trapezoidal shape as the side end surface 15b of the convex portion 15. It is configured to have a shape.

1A and 1B show the relationship between the receiving portion 16 and the fitting portion 14 when the fitting portion 14 shown in FIG. 5 is fitted to the receiving portion 16 shown in FIGS. 6A, B, and C. 7A is a plan view, and FIG. 7B is a developed view of the side end surface 17a constituting the receiving portion 16 viewed from the central axis O shown in FIG. 7A. It shows.

In FIGS. 7A and 7B, A1 to A6 are the apexes of the regular hexagonal receiving part formed by the side end surface 17a of the receiving part 16, and B1
to B6 are the fitting part vertices of the distal end surface 15a of the fitting part 14 shown in FIG. The fitting is performed when the fitting is in the angular position, and a represents the contact locus between the fitting part vertices B1 to B6 and the side end surface 17a of the receiving part 16, respectively.

FIG. 7A when the receiving part 16 and the fitting part 14 start fitting together.
If the positional relationship is as shown in the figure, the fitting portion vertices BI to B6 are located near the center of the contact locus α, respectively, as shown in FIG. 7B.

In this state, when the fitting part 14 is pressed against the receiving part 16 in the direction of arrow B in FIG. 7B, the receiving part 16 and the fitting part 1
Even considering that there is a movement in the relative angular position between B1 and B6, the apexes B1 to B6 of the fitting portions do not receive the force that is moved in the convex direction of the arrow in the figure on the contact locus α, respectively. Part vertex A
1 to A6 cannot be matched.

This is based on the fact that the contact locus α is formed by a gentle circular arc as shown in FIG. 7B.

Therefore, the conventional shaft coupling device configured in this way is
When applied to the electric drill device shown in Figures 4 to 4,
In order to obtain sufficient mating, the apex B of the mating part must be
The fitting operation becomes troublesome because relative positioning must be performed between the fitting part 14 and the receiving part 16 so that the vertices A1 to A6 of the receiving part face each other.

As shown in FIG. 3, the shape of the tip of the fitting portion 10 (fitting portion 14) is difficult to recognize from the operator's perspective, making the angular positioning difficult.

Figures 8A, B, and C and Figures 9A, B, and C show a receiving part and a fitting part constituting a shaft coupling device according to an embodiment of the present invention, and Figure 8A shows the receiving part of the above-mentioned part. A perspective view, FIG. 8B is a plan view thereof, FIG. 8C is a cross-sectional view taken along the line X2-X' shown in FIG. 8B, and FIG. 9A/ri is a perspective view of the above fitting part, FIG. 9B shows its plan view, and FIG. 9C shows its front view.

In the case of the present invention, the difficulty as explained with reference to FIG. An attempt is made to provide a shaft coupling device that is shaped so that movement can occur.

In FIGS. 8A, B, and C, 7 is a receiving portion, 1a is a recessed receiving portion provided in the receiving portion 7, 7b is the tip end surface of the receiving portion I,
Reference numeral 18 denotes a deep inner wall which together with the notch surface 19 forms the recessed receiving part 1a, 19 a conical notch surface, 20 a ridgeline formed by the mutually adjacent notch surfaces 19, and C1 to C6 the above-mentioned Vertex of notch surface 19, Dl to B6
are the apex, ridge, or 0/6 of the deep side of the ridge line 20, respectively.
are the vertices on the distal end surface 7o side of the ridge line 20, respectively, and El to B6 are virtual vertices, respectively, and when the fitting part 10, which will be described later, is about to be fitted, the fitting part 10, which will be described later, is the vertex F1.
It represents the point on the locus where B6 to B6 would be located.

As is clear from the plan view of the receiving part shown in FIG. 8B, the deep inner wall 18 forms a regular hexagon, and the ridge line 20 is provided at a midpoint between each side of this regular hexagon and perpendicular to each side. .

Further, as is clear from FIG. 8A, the cutout surface 19 is cut out to include the virtual vertices E1 to E6.

In FIGS. 9A, B, and C, 10 is a fitting part, 10a is a convex part of the fitting part 10 that is fitted into the concave receiving part 1a of the receiving part 1, and 10b is the fitting part 10. , 21 is a side wall surface, 22 is an inclined surface provided between the above-mentioned end surface 10b and the above-mentioned side wall surface 21, 23 is a ridgeline formed by the above-mentioned inclined surfaces 22- adjacent to each other, Fl to F6
G1 to G6U represent the apex formed by the side wall surface 21 and the inclined surface 22, and the apex formed by the tip surface 10b and the inclined surface 22, respectively.

Furthermore, the broken line m shown in FIG. 9A represents the virtual side of the polygon formed when a thread is stretched in a straight line between the vertices G1 to 06, and the broken line n represents the case where the vertices F1 to F6 are connected. represents the virtual sides of a polygon formed in .

The side wall surface 21 has a regular hexagonal shape, as is clear from the plan view of the fitting part shown in FIG. deep inner wall 1
8 to transmit driving force (for example, transmit rotational driving force from the receiving part 7 side to the fitting part 10 side).

That is, the regular hexagon formed by the vertices F1 to F6 shown in FIG. 9B is configured to have a congruent relationship with the regular hexagon formed by the vertices C1 to C6 shown in FIG. 8B.

Further, the inclined surface 22 is clearly formed in FIG. 9A.

The tip end face 10b side is hollowed out so as not to include the virtual side m, and the side wall surface 21 side is hollowed out so as not to include the virtual side n.

In other words, when it is assumed that the fitting portion convex portion 10a is given a shape based on the virtual side m and the virtual side nx, the inclined surface 22 has the shape of the virtual side m and the virtual side nx. This corresponds to the cutout surface when the trapezoidal surface formed by side n is cut out.

FIGS. 10A and 10B show the relationship between the receiving part 7 and the above-mentioned fitting when the fitting part 10 shown in FIGS. 9A, B, and C is fitted to the receiving part 7 shown in FIGS. 8A, B, and C. 10A is a plan view, and FIG. 10B is a developed view of the receiving portion 1 viewed from the central axis O shown in FIG. 10A.

In FIGS. 10A and 10BK, β represents a locus where the fitting part vertices F1 to F6 contact the receiving part notch surface 19,
Other symbols are A, B, C in Fig. 8 and A, B, C in Fig. 9.
It corresponds to the sign of

FIG. 10A when the receiving part 7 and the fitting part 10 start fitting together.
If the positional relationship was as shown in the diagram, then Figure 10B
As shown in the figure, the apexes F1 to F6 of the fitting part are the contact locus β.
It is located near the upper ridgeline 20.

In this state, when the fitting part 10 is pressed against the receiving part 7 in the two directions indicated by the arrows in FIG. 10B, the receiving part 7 and the fitting part 10
Due to the movement of the angular position between , the fitting part vertices F1 to F6 receive a force that is moved approximately linearly in the direction of arrow H in the figure on the contact locus β, and the fitting part vertices coincide with the receiving part vertices C1 to C6. It becomes like this.

This is based on the fact that the contact locus β is given an acute linear shape as shown in FIG. 10B in response to the pressing forces in the two directions shown above.

Therefore, even if the relative angular positional relationship between the receiving part 7 and the fitting part 10 at the start of fitting has a substantially perpendicular positional deviation as shown in FIGS. 10A and 10B, the receiving part 7 and the fitting part 10 10 becomes easy to fit.

That is, in the case of the present invention, there is no need for relative angular alignment between the receiving portion 16 and the fitting portion 14, which was required in the fitting operation in the conventional shaft coupling device described above.

One embodiment of the present invention has been described above, and here, the structures corresponding to the claims section of the present application will be indicated in association with the reference numerals of the above embodiment.

That is, the cross-sectional pressure seen in the longitudinal direction from the end face 7b is a convex polygonal shape (where n is an integer of 3 or more), and the apex of the convex polygon with contact pressure n is 3C2..., C6 to the above. A receiving part 7 having a concave receiving part 7a formed of a cavity having an internal edge extending in the longitudinal direction, and a cross-sectional pressure n convex polygonal shape corresponding to the cross-sectional pressure n convex polygonal shape of the concave receiving part 7a. A fitting part 10 having a convex part 10a formed of a columnar body is provided, and the cross-sectional pressure n of the convex polygonal shape is provided in the PIft surface front length n convex polygonal part Ia of the receiving part 7. In a shaft coupling device that transmits rotational driving force from one side of the receiving part 1 or the fitting part 10 to the other side by fitting the convex part 10a, the receiving part 1 includes: A right angle from the middle point of the side connecting the mutually adjacent vertices C and C, C and C, ... C and C1 of the cross-sectional pressure n convex polygon of the receiving part 1 to the said side. There are a plurality of ridgelines 20 extending in the direction of the end surface 7b, and a conical cutout surface 19 having a surface passing through two mutually adjacent ridgelines 20.degree. 20 and the one apex, for example C1, With respect to the end surface 7b of the portion 1, each of the vertices, for example C1s, C2, .
N pieces are formed in a shape corresponding to C6, and the fitting part 10 is removably fitted into the recessed receiving part 7a along the notch surface 19. Convex part 10a of fitting part 10 in relation to FIG.
The reason for this is that the tip surface 10b of the fitting portion has an inclined surface 22, as will be described later with reference to FIG.
It may be considered that this is to prevent undesired contact with the ridge line 20 existing in the receiving portion 7.

The reason is explained below. Figure 11 A, B is Figure 8 A, B
, C and the ridge line 20 of the receiving part I according to the present invention shown in FIG. 9A,
B and C are explanatory diagrams for explaining the relationship between the fitting part 10 and the inclined surface 22 according to the present invention, in which FIG. 11A is a partial plan view, and FIG. 11B is a partial plan view of FIG. A cross-sectional view taken along the line X'3- is shown.

In both figures, the case where the fitting part 10 shown in FIG. 9 is fitted is compared with the case where the fitting part 14 shown in FIG. 5 is fitted.

In FIG. 11A, the arcuate portion q indicated by the broken line is the ninth
When the fitting part 10 according to the present invention shown in Figures A, B, and C is fitted to the receiving part 7 according to the present invention, when the fitting part 10 is cut along a plane including the imaginary side n shown in Figure 9A. The shape of the cross section of the inclined surface 22, the straight line r shown by the dashed line in the figure, is the trapezoidal base of the fitting part 14 when the conventional fitting part 14 shown in FIG. Each side of the regular hexagon formed by

When the conventional fitting part 14 as shown in FIG. 5 is fitted to the receiving part 7 in a positional relationship as shown in FIG. 11A,
As shown in FIG. 11B, the ridge line 20 of the receiving part 7 and the fitting part 1
The straight line portion r of No. 4 comes to have a contact relationship at the point M shown in the figure.

Therefore, the fitting portion 14 cannot come into contact with the receiving portion cutout surface 19, and fitting cannot be achieved.

When the fitting part 10 according to the present invention shown in FIGS. 9A, B, and C is fitted to the receiving part 1, the arcuate part q does not come into contact with the ridgeline 20 as shown in FIG. 11AK.

That is, the inclined surface 22 of the fitting part 10 is formed when the fitting part 10 faces the receiving part 7 with a relative positional relationship as shown in FIG. Even in the case where it has a ridge line 20 of the receiving part 1, it does not have a contact relationship with the ridge line 20 of the receiving part 1.

Therefore, the fitting portion vertices F1 to F6 come into contact with the receiving portion notch surface 19 and easily match the receiving portion vertices CI to C6 as explained in FIGS. 10A and 10B.

12A, B, and C show another embodiment of the receiving portion of the present invention, FIG. 12A is a perspective view thereof, FIG. 12B is a plan view, and FIG.
FIG. 2C shows a sectional view taken along the line X4-X'4 shown in FIG. 12B.

The symbols A, B, and C in FIG. 12 correspond to those represented by the symbols A, B, and C in FIG. 8.

In the case of this embodiment, the cutout surface 19 is a flat surface,
The plane has a ridgeline 20, and the trajectory formed by the virtual apex E1, Iyz I, E6, does not exist on the front surface near the intermediate point between the ridgelines 20 and 20 that are adjacent to each other.

The main differences between this embodiment and the conventional configuration shown in FIG.
Vertices AI, A2...s A6 shown in Fig. 7
The vertices C1t and C2 shown in FIG.
,...

[Position D] where C6 is located at a deeper position in the longitudinal direction from the end surface 7b and the ridge line 20 is generated]
tD2... is the corresponding vertex C], C2...
It is located at a shallower position than the

13A and 13B are the fitting portions 14 shown in FIG.
FIG. 13 is an explanatory diagram illustrating the relationship between the regular hexagon formed by 0 and the regular hexagon formed congruently with the regular hexagon formed by the vertices C1 to C6 of the receiving portion 7; , and FIG. 13B respectively show developed views when viewed from the IJO shown in FIG. 13A to the receiving part 7.

In FIGS. 13A and 13B, γ represents the contact locus between the cutout surface 19 of the receiving portion 7 and the vertices B/1 to B10 of the fitting portion 14, and other symbols represent those corresponding to the above-mentioned symbols. There is.

In the case of this embodiment, as is clear from FIG. 13B, the contact locus γ is represented by a curved line from the vertices D/1 to D'6 of the tip surface 7b of the receiving part 7 toward the receiving part vertices C1 to C6, The slope near the ridgeline 20 has a slight roundness.

That is, the contact locus γ in this embodiment is as shown in FIG. 8 A, B, and C.
Compared to the contact trajectory β shown in FIG. 10B in the case of the receiving portion 1 according to the embodiment of the present invention shown in FIG. 10, the slope is relatively gentle near the receiving portion ridge line 20, As is clear from FIG. 7B, the slope is steeper than that of the conventional receiving portion 16 shown in FIG.

Therefore, in this embodiment as well, if slippage between the receiving portion 7 and the fitting portion 14 is taken into consideration, the fitting operation between the two can be performed using only a pressing force, thereby facilitating the fitting operation.

14A and 14B show the relationship between the ridgeline 20 of the receiving part 1 and the fitting part 14 when the fitting part 14 is fitted to the receiving part 7 as shown in FIGS. 13A and B. 14A is a partially enlarged plan view of FIG. 13A, and FIG. 14B is a sectional view taken along line X5-X'5 shown in FIG. 14A. .

In FIGS. 14A and 14B, point N points the fitting part 14 to the ridge line 20.
13 represents the top of the cross section of the fitting part 14 when cut along a cutting plane (plane formed by line X5-X'5 in the figure) including There is.

Since the notch surface 19 of the receiving part 1 is configured as a flat surface as described above, the contact relationship between the fitting part 14 and the receiving part notch surface 19 is at the fitting part apex B'1, as shown in FIG. 14B. Or B1
0, and on the other hand, the apex N of the cross section of the fitting portion does not contact the ridge line 20 of the receiving portion.

That is, when fitting the fitting part 14 to the receiving part 7, the fitting is not hindered by the receiving part ridge line 20.

In this way, in the case of the receiving portion of this embodiment shown in FIGS.
Molding is easier than in the embodiment receiving portions shown in Figures A, B, and C.

In addition, in the case of the receiving part of this embodiment, the fitting part 14 formed of a straight part as shown in FIG. It goes without saying that it is also possible to use the joining part 10.

). Therefore, compared to the receiving parts shown in Fig. 8A, B, and C, the molding work of the fitting part is easier, and the wear caused by the contact of the apex of the fitting part with the cutout surface of the receiving part during fitting is reduced. You can force it.

As described above, according to the present invention, when either the receiving part side or the fitting part side or both are in a rotatable state at the time of fitting, the receiving part and the fitting part are pressed against each other. Since the fitting parts rotate relative to each other so as to fit into each other, this is extremely effective, especially when the shape of the tip end of either the receiving part or the fitting part, or both, cannot be seen from the operator's perspective. becomes.

That is, in the past, even if the operator tried various corner positions of the fitting part with respect to the receiving part in a position that was not visible to the operator by trial and error, the fitting could not be completed successfully and the operator was confused. Accordingly, reliable fitting can be obtained almost immediately.

[Brief explanation of drawings]

FIG. 1 is a cross-sectional view of an electric drill in which a drill is used as an attachment as an example of an electric device to which the present invention is applied;
The figure is a cross-sectional plan view showing the main parts, Figure 3 is an explanatory diagram to explain the main body case, attachment, and connector, Figure 4 is a front view of the main body case, and Figure 5 is a conventional fitting part. A perspective view showing an example; FIGS. 6A, B, and C are examples of a receiving part corresponding to the fitting part, and FIGS. 1A and B are perspective views for explaining the relationship between the fitting part and the receiving part. Explanatory diagram, Figure 8A. B and C are receiving portions in a shaft coupling device according to an embodiment of the present invention; FIGS. 9A, B, and C are fitting portions that are fitted into the receiving portions; FIGS. 10A and B; and FIG. 11A; B is an explanatory diagram showing the relationship between the receiving part and the fitting part in the shaft coupling device, and FIGS. 12A and B
, C1/'i, A receiving part in a shaft coupling device according to another embodiment of the present invention, FIGS. 13A and B and FIGS. 14A and B are diagrams for explaining the relationship between the receiving part and the fitting part. An explanatory diagram is shown. In the figure, 1 is a receiving part according to the present invention, 7a is a concave receiving part, 7b is a tip end face of the receiving part, 10 and 14 are fitting parts, 10a is a convex part of the fitting part 10, 19 is a notch surface, and 20 is a ridgeline. , El to E6 represent the vertices of the polygonal shape of the receiving part 1.

Claims (1)

[Claims] 1 In a cavity that has an n-convex polygonal shape in cross section (where n is an integer of 3 or more) when viewed from the end face in the longitudinal direction, and has an internal edge extending in the longitudinal direction from the apex of the n-convex polygon. a receiving part having a concave receiving part; and a fitting part having a convex part formed of a columnar body having an n-convex polygonal shape in cross section corresponding to the n-convex polygonal shape in cross section of the concave receiving part. and fitting the convex part having an n-convex polygonal shape in cross section into the concave receiving part having an n-convex polygonal shape in cross section in the above-mentioned forked part, and making sure that either the receiving part or the fitting part is dislocated. In the shaft coupling device for transmitting the rotational driving force from one side to the other side, the receiving portion has a side connecting the mutually adjacent vertices of the n-convex polygon in the cross section of the receiving portion. There is a plurality of ridge lines extending perpendicularly to the side from the middle point in the direction of the end surface, and there is a conical cutout surface having a surface passing through two ridge lines adjacent to the pressure and the one vertex. , n pieces are formed on the end face of the receiving part in a shape corresponding to each of the vertices, and the fitting part is removably fitted into the recessed receiving part along the notch surface. A shaft coupling device characterized by: