JP2014047873A - Coupling - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a stress of a coupling connecting member at the time of transmitting torque.SOLUTION: There are provided two solid bodies 20 and 20 separately fixed to two revolving shafts 84a and 85 and a connection member 30 inserted into the solid bodies in which each of the solid bodies has a body part 21 into which the revolving shafts are inserted and convex projection parts 22 that are formed side-by-side in a uniform space around the outer periphery of the body part, each of the projection parts is formed over an entire length of the body part and provided with an extention part 23 formed projecting from one end of the body part, each of the solid bodies is connected under a state in which their projection parts are alternatively arranged in a peripheral direction and mutual solid bodies are connected while they are inserted inside of each of the extention parts of mating solid body, the connection member is provided with a plurality of insertion parts 31 arranged in a clearance of each of the projection parts and a length of each of the insertion parts in a rotation center line direction is set to equal to the entire length of the projection part.

Description

  The present invention relates to a coupling that connects two rotating shafts.

When two rotating shafts are arranged concentrically and torque is transmitted between them, the rotating shafts are connected to each other by coupling.
FIG. 11 is an exploded perspective view of a coupling 100 that has been widely used. As shown in this figure, a conventional coupling 100 is interposed between a hub 110 and 120 fixed to a power-side rotating shaft and a load-side rotating shaft, respectively, and between the hubs 110 and 120. And a connecting member 130 that allows a shift between the axial centers of the rotating shaft and the load-side rotating shaft.

The hubs 110 and 120 have substantially the same structure, and cylindrical main body portions 111 and 121 into which the power-side or load-side rotation shafts are inserted, and the center line direction from one end face of the main body portions 111 and 121. Are provided with three protrusions 112 and 122 extending along the line (one of the protrusions 122 is not shown).
The main body portions 111 and 121 are formed with screw holes 111a and 121a penetrating to the inside along the radial direction thereof, with respect to the rotating shaft on the power side or the load side inserted inside the main body portions 111 and 121. It is fixed by a headless screw (not shown).
The three protrusions 112 and 122 are provided at uniform intervals in the circumferential direction on one end face of the main body 111 and 121. The main body portions 111 and 121 and the projecting portions 112 and 122 are integrally formed of the same metal material.

The connecting member 130 includes a cylindrical main body 131 and six protrusions 132 extending radially outward on the outer peripheral surface thereof, which are integrally formed from an elastic material such as rubber. Yes.
The main body 131 has a smaller diameter than the hubs 110 and 120 and can be disposed inside the protrusions 112 and 122 of the hubs 110 and 120.
Each protrusion 132 is provided on the outer peripheral surface of the main body 131 at a uniform interval in the circumferential direction, and a recess 134 is formed between the adjacent protrusions 132.

The hub 110 and the hub 120 are connected by inserting a connecting member 130 in a state where the end surfaces on which the protrusions 112 and 122 are formed face each other.
At this time, the protrusions 112 of the hub 110 and the protrusions 122 of the hub 120 are inserted into the recesses 134 of the connecting member 130 so as to be alternately arranged.

When the shaft center shifts between the power-side rotating shaft and the load-side rotating shaft, a load is generated during torque transmission, which becomes a torque transmission loss.
In the coupling 100, the protrusion 132 of the coupling member 130 is inserted between the protrusion 112 of the hub 110 and the protrusion 122 of the hub 120. Even when there is a variation in the interval between each other, each projection 132 of the connecting member 130 expands and contracts to absorb this, and torque transmission loss can be reduced.

  As described above, the coupling 100 enables torque transmission with little loss between the rotating shafts, but the three members of the hub 110, the connecting member 130, and the hub 120 are connected side by side along the center line direction of the rotating shaft. In this case, there is a problem that the size tends to increase in the center line direction.

For this reason, in order to solve the above problem, a coupling 200 having a structure shown in FIG. 12 has been proposed.
The coupling 200 includes hubs 210 and 220 fixed to a power-side rotating shaft and a load-side rotating shaft, respectively, and a connecting member 230 interposed between the hubs 210 and 220 (for example, Patent Document 1).

One hub 210 includes a cylindrical main body 211 and three protrusions 212 provided on one end surface thereof, and has substantially the same structure as the hub 110 described above.
The other hub 220 includes a cylindrical main body 221 and three protrusions 222 extending outward in the radial direction on the outer peripheral surface thereof.
The main body 221 of the hub 220 has a smaller diameter than that of the hub 210 and can be disposed inside each protrusion 212 of the hub 210.
The protrusions 222 are provided at regular intervals in the circumferential direction on the outer peripheral surface of the main body 221, and the outer diameter at the tip is equal to the outer diameter of the hub 210.
Further, the thickness in the center line direction of the other hub 220 is equal to the protruding length in the center line direction of the protrusion 212 of the one hub 210, and the three protrusions 212 of the one hub 210 are connected to the other hub 220. It can be accommodated in the area inside the.

The connecting member 230 is positioned next to the six insertion portions 231 disposed in the circumferential gap between the three protrusions 212 of the one hub 210 and the three protrusions 222 of the other hub 220. And six connecting portions 232 for connecting the insertion portions 231 to each other.
The connection part 232 is alternately connected with one end part and the other end part in the center line direction of the insertion part 231 arranged along the circumferential direction, thereby integrating the connection member 230 in an annular shape. Yes.
With this structure, the connecting member 230 is formed with three recesses 233 that open toward the one hub 210 and three recesses 234 that open toward the other hub 220. When connecting the hubs 210 and 220, the protrusions 212 of the hub 210 are inserted into one recess 233, and the protrusions 222 of the hub 220 are inserted into the other recess 234. Thereby, the other hub 220 can be accommodated in the inner region of each protrusion 212 of the one hub 210 with the connecting member 230 interposed.
As a result, the coupling 200 enables torque transmission from the power-side rotating shaft to the load-side rotating shaft while reducing the loss of elasticity of each insertion portion 231 of the connecting member 230.
Further, since the other hub 220 is accommodated in the inner region of each protrusion 212 of the one hub 210, it is possible to reduce the size by the length of the hub 220 in the center line direction.

Chinese Patent Application Publication No. 200940202

When torque transmission is performed by connecting the rotating shafts via the coupling 200, a load during rotation is mainly generated on the side surfaces of the protrusions 212 and 222.
On the other hand, in order to reduce the size of the coupling 200, the area of the side surface of each of the protrusions 212 and 222 is smaller than that of the conventional one, and accordingly, the side surface of the protrusion 212 and the side surface of the protrusion 222 The contact area of the insertion member 231 of the connecting member 230 sandwiched between the contact members 230 is also small. As a result, the insertion portion 231 of the connecting member 230 has a higher load per unit area than before, so that it is made of an expensive material such as a polyurethane elastomer that is superior in durability to suppress wear and deterioration. There was a problem that had to be formed.

  An object of the present invention is to improve the durability of the coupling member while reducing the size of the coupling.

  The invention according to claim 1 is a coupling comprising two fixed bodies individually fixed to two rotating shafts and a connecting member made of an elastic body interposed between the fixed bodies. One fixed body includes a cylindrical main body portion into which each of the rotation shafts is inserted, and a rotation center line direction of the rotation shaft formed in a plurality at a uniform interval in the circumferential direction on the outer peripheral surface of the main body portion. And the plurality of protrusions are formed over the entire length of the main body portion in the direction of the rotation center line and from the one end portion of the main body portion to the rotation center line. The two fixed bodies are arranged so that their protrusions are alternately arranged along the circumferential direction and the main body portions are connected to each other. Connected in a state of being inserted inside the plurality of extending portions. The connecting member includes a plurality of insertion portions arranged in a plurality of gaps of the protruding portions alternately arranged along the circumferential direction, and the length of the plurality of insertion portions in the rotation center line direction is set. It is characterized by being equal to the total length of the protrusion.

  The invention according to claim 2 has the same configuration as that of the invention according to claim 1, and the total length of the protrusions of the two fixed bodies in the direction of the rotation center line is interposed via the connecting member of the two fixed bodies. It is characterized by being equal to the length at the time of connection.

  The invention described in claim 3 has the same configuration as that of the invention described in claim 1 or 2, and the connecting member is located next to each other among the plurality of insertion portions arranged along the circumferential direction. A plurality of connecting portions that alternately connect one end portions and the other end portions of the two insertion portions in the rotation center line direction in the circumferential direction are provided.

  The invention according to claim 4 has the same configuration as that of the invention according to claim 3, and allows the connecting portion of the connecting member to pass through the front end surface side in the extending direction of the extending portion of the fixed body. It is characterized by having a shape along the tip surface.

  The invention according to claim 5 has the same configuration as that of the invention according to claim 3, and the connecting portion of the connecting member is connected to the extending portion of one of the fixed bodies and the main body portion of the other fixed body. And a shape along the outer peripheral surface of the main body portion of the other fixed body.

According to the first aspect of the present invention, a fixed body is fixedly mounted on one and the other of the concentric rotating shafts, and the fixed bodies are connected via a connecting member.
At this time, the length of the connected two fixed bodies in the direction of the rotation center line can be shortened by inserting the main body portions inside the extending portions of the respective fixed bodies.
On the other hand, since each protrusion part is provided with the extension part, the length can be made longer than a main-body part, and the side surface area of a protrusion part can be expanded. And since the length of the rotation center line direction of the insertion part of the connection member inserted between two projection parts is made equal to the full length of a projection part, a projection part and an insertion part mutually contact area Can be expanded.
As a result, it is possible to reduce the load per unit area applied from the protrusion to the insertion portion during torque transmission from the rotating shaft to the rotating shaft, avoiding deterioration of the connecting member, and extending the life. Is possible. In addition, in connection with this, since the material for the connecting member is not limited to an expensive material that can withstand a high load, the manufacturing cost of the coupling can be reduced.

  In the invention according to claim 2, since the total length of each protrusion of the fixed body is made equal to the length when the fixed bodies are connected via the connecting member, the contact between the connecting portion and the protruding portion with respect to the length of the coupling The area can be secured to the maximum, and the load per unit area that is efficiently applied to the connecting portion of the connecting member can be reduced while reducing the size of the coupling.

In the invention according to claim 3, since the plurality of insertion portions of the connecting member are connected by the plurality of connecting portions, the members can be integrated, and the workability of the assembly of the coupling can be improved. Become.
Further, since the plurality of connecting portions alternately connect one end portions and the other end portions in the rotation center line direction of the two adjacent insertion portions in the circumferential direction, each connecting portion has one end portion. When the projections of the two fixed bodies are alternately arranged in the circumferential direction, the coupling portions do not hinder the coupling. It has become.

  According to a fourth aspect of the present invention, the connecting portion of the connecting member is formed along the leading end surface while passing the leading end side in the extending direction of the extending portion of the fixed body. For example, when the connecting portion is shaped along the outer peripheral surface of the main body portion of the fixed body, the connecting portion is provided between the outer peripheral surface of the main body portion of one fixed body and the inner surface of each protruding portion of the other fixed body. Although it is necessary to form a gap for passing through, since the gap is not necessary when the connecting portion passes the distal end surface side of the extending portion, it is possible to reduce the size by reducing the diameter of the coupling.

The invention according to claim 5 allows the connecting portion of the connecting member to pass between the extending portion of one fixed body and the main body portion of the other fixed body and along the outer peripheral surface of the main body portion of the other fixed body. Therefore, the connecting portion is interposed between the inner surface of each extending portion of one fixed body and the outer peripheral surface of the main body portion of the other fixed body.
For example, when the rotation center line of each rotating shaft is completely displaced, the inner surface of each extending portion of one fixed body and the outer peripheral surface of the main body portion of the other fixed body are in direct contact with each other. Although vibration may cause wear or torque transmission loss, wear can be prevented and torque transmission loss can be reduced by the presence of a connecting portion of a connecting member made of an elastic body.

It is the front view which notched a part of sewing machine carrying the coupling of this invention. It is sectional drawing of the circumference | surroundings of a sewing machine motor. It is a disassembled perspective view of the surrounding structure of a sewing machine motor. It is a perspective view of the coupling which is this invention. It is a disassembled perspective view of a coupling. It is the side view which looked at the coupling from the direction of the rotation center line. It is a disassembled perspective view of the 1st modification of a coupling. It is a perspective view of the 2nd modification of a coupling. It is a perspective view of the 3rd modification of a coupling. It is the graph which showed the calculation result of the stress added to the contact surface of the projection part and insertion part of this invention and the conventional coupling. It is a disassembled perspective view of the coupling which has spread widely conventionally. It is a disassembled perspective view of another conventional coupling.

[Outline of sewing machine with coupling]
As an embodiment of the present invention, a case where the coupling 10 is mounted on the sewing machine 80 will be described as an example. FIG. 1 is a front view in which a part of the sewing machine 80 is cut away.
The sewing machine 80 includes a sewing machine frame 81 that supports the entire configuration, a needle bar 83 that holds the sewing needle 82 and is supported by the sewing machine frame 81 so as to be movable up and down, and a sewing machine that is a driving source for the vertical movement of the needle bar 83. The motor 84, the upper shaft 85 disposed on the same rotation center line as the output shaft 84a of the sewing machine motor 84, the coupling 10 connected to the output shaft 84a and the upper shaft 85 so as to be able to transmit torque, and the upper shaft 85 A fixedly equipped needle bar crank 86, a crank rod 87 connecting the needle bar crank 86 and the needle bar 83, a lower shaft 88 disposed parallel to the upper shaft 85 at the lower part of the sewing machine 80, and an upper shaft 85 A driven pulley 89 fixedly mounted on the shaft, a driven pulley 90 fixedly mounted on one end of the lower shaft 88, and a timing for transmitting torque from the driven pulley 89 to the driven pulley 90. And Guberuto 91, provided at the other end of the lower shaft 88, and a hook (not shown) entangled with the lower thread to the upper thread passed through the needle 82.

  The sewing machine frame 81 includes a bed portion 81a that extends in a certain direction at the lower part of the sewing machine, a vertical body portion 81b that stands on one end of the bed portion 81a, and a parallel to the bed portion 81a from the upper portion of the vertical body portion 81b. And an arm portion 81c extending in the direction.

The lower shaft 88 is rotatably supported in the bed portion 81a in a state of being parallel and horizontally oriented in the longitudinal direction of the bed portion 81a.
One end portion of the lower shaft 88 is fixedly equipped with the driven pulley 90 described above, and a rotating operation in a certain direction is transmitted from the upper shaft 85.
The other end of the lower shaft 88 is equipped with the aforementioned hook. The hook is a so-called full-rotation vertical hook, and since its structure is well known, detailed description thereof is omitted.

The upper shaft 85 is rotatably supported in the state of being parallel to the longitudinal direction of the arm portion 81c and horizontally oriented in the arm portion 81c.
In the vicinity of one end of the upper shaft 85, the above-described main driving pulley 89 is fixedly mounted, and torque is transmitted to the lower shaft 88 via the timing belt 91.
The above-described needle bar crank 86 is fixed to the other end of the upper shaft 85, and the needle bar crank 86 rotates around the upper shaft 85. An upper end portion of the crank rod 87 is coupled to a position eccentric from the center of rotation of the needle bar crank 86 so as to be rotatable about an axis parallel to the upper shaft 85.
On the other hand, a needle bar hanger 92 that is hung and fixed to the needle bar 83 is connected to the lower end portion of the crank rod 87 so as to be rotatable about an axis parallel to the upper shaft 85.
For this reason, when the upper end portion of the crank rod 87 performs a circular motion around the upper shaft 85 by the needle bar crank 86, only the vertical component of the circular motion is transmitted to the lower end portion of the crank rod 87, and the needle bar 83. It is possible to give an up and down movement operation.

2 is a sectional view around the sewing machine motor 84, and FIG. 3 is an exploded perspective view. The sewing machine motor 84 is attached to the upper surface of the vertical body 81b of the sewing machine frame 81 on the side opposite to the arm 81c via a motor mounting base 93.
The sewing machine motor 84 includes an output shaft 84a penetrating the center thereof, one end of which is connected to the upper shaft 85 via the coupling 10, and the other end is equipped with a pulley 94 for manual rotation. Yes. The output shaft 84a is connected by the coupling 10 so as to be concentric with the upper shaft 85, that is, to rotate simultaneously around the same rotation center line C.

  The motor mounting base 93 is a substantially rectangular frame, and an opening 93a is formed in the central portion thereof for loosely inserting the output shaft 84a of the sewing machine motor 84 and fitting into a cylindrical portion 81d provided in the vertical body portion 81b. Is formed. The end of the sewing machine motor 84 on the side of the sewing machine frame 81 is fixed to the motor mounting base 93 by a set screw (not shown), and the motor mounting base 93 is fixed to the vertical body 81b by bolting.

A substantially cylindrical upper shaft support 95 is attached to the inside of the cylindrical portion 81d provided in the vertical body portion 81b. The upper shaft support 95 has a metal bearing 95a that supports one end portion of the upper shaft 85 so as to be rotatable by sliding, and an oil seal 95b provided adjacent to the outer side of the metal shaft 95a.
Further, the upper shaft support 95 is formed with a circular concave portion 95c at the end on the sewing machine motor 84 side. The inner diameter of the concave portion 95c is set to be somewhat larger than the outer diameter of the coupling 10 described later, and it is possible to dispose one end portion of the coupling 10 inward without causing contact. .

[Coupling]
4 is a perspective view of the coupling 10, and FIG. 5 is an exploded perspective view. The coupling 10 mainly includes hubs 20 and 20 as two fixed bodies, each of which is equipped with an output shaft 84a of a sewing machine motor 84 serving as a rotating shaft and an upper shaft 85 serving as a rotating shaft in an individually opposed state. When these hubs 20 and 20 are connected, a connecting member 30 made of an elastic body is provided between them.

Since the hub 20 mounted on the output shaft 84a of the sewing machine motor 84 and the hub 20 mounted on the upper shaft 85 have the same structure, only one hub 20 will be described.
The hub 20 includes a cylindrical main body 21 into which the output shaft 84a or the upper shaft 85 of the sewing machine motor 84 is inserted, and three protrusions formed to protrude outward in the rotational radial direction from the outer peripheral surface of the main body 21. 22 and these are integrally formed of the same metal material.

The inner diameter of the main body 21 is substantially equal to the outer diameters of the output shaft 84a and the upper shaft 85 of the sewing machine motor 84, and can be inserted.
In addition, the outer diameter of the main body 21 and the length in the direction of the rotation center line C are preferably smaller because of the demand for downsizing of the coupling 10, but in the usage environment, depending on the relationship with the forming material, It is set to a value that provides at least the durability and strength of the specified service life.
In the sewing machine 80, the output shaft 84a of the sewing machine motor 84 and the outer shaft 85 have the same outer diameter. However, if these outer diameters are different, the main body portion 21 has an inner diameter corresponding to each outer diameter. Each hub 20 is individually equipped. Further, even when the inner diameters of the individual main body portions 21 are different as described above, it is desirable that the outer diameters of the main body portions 21 are equal to each other.

The three protrusions 22 are arranged at equal intervals in the circumferential direction, and the radially outer surface of each protrusion 22 is a circumferential surface centered on the rotation center line C.
Each of the protrusions 22 has a protrusion along the rotation center line C, and is extended from one end of the main body 21 so as to protrude in a certain direction along the rotation center line C. The unit 23 is provided.
FIG. 6 is a side view of the coupling 10 as viewed from the direction of the rotation center line C. FIG. As shown in the figure, the forming angle θ1 of the protrusion 22 around the rotation center line C is somewhat smaller than 60 °, which is a six-divided portion of 360 °. Further, the inner diameter R <b> 1 of the extending part 23 is somewhat larger than the outer diameter of the main body part 21 described above, and the length of the extending part 23 in the direction of the rotation center line C is larger than the length of the main body part 21. Is also somewhat longer. Thereby, the front-end | tip part of the extension part 23 of one hub 20 and the rear-end part (end part on the opposite side to the extension direction of the extension part 23) of the main-body part 21 of the other hub 20 correspond. When the hubs 20 and 20 are connected to each other, a gap can be formed between the end surfaces of the main body portions 21 and 21. Even if the output shaft 84a and the upper shaft 85 of the sewing machine motor 84 are slightly misaligned in the axial center, if the main body portions 21 and 21 are in direct contact with each other, it may cause a load of torque transmission. This is alleviated by the gap. Further, in the coupling 10, an elastic partition wall 33 (described later) is provided in the connecting member 30, and the partition wall 33 having a thickness matching the gap between the main body portions 21, 21 is interposed between the coupling member 30 and the torque. The transmission load is reduced.

When connecting the two hubs 20, 20, the extended portions 23, 23 of the protrusions 22, 22 are arranged on the same rotation center line C in the facing direction, and the protrusion 22 of one hub 20 is connected. Each protrusion of one hub 20 until the tip of the extension 23 reaches the rear end of the protrusion 22 of the other hub 20 (the end opposite to the extension 23 in the direction of the rotation center line C). Each extending portion 23 of the other hub 20 is inserted into the concave portion 24 between the two.
As a result, the two hubs 20 and 20 are in a state in which the protrusions 22 and 22 are alternately arranged along the circumferential direction around the rotation center line C, and the main bodies 21 and 21 are connected to each other. It becomes the state loosely inserted in the area | region inside each of these extension parts 23 and 23.
Then, according to the dimension setting shown in FIG. 6, between the protrusion 22 of one hub 20 and the protrusion 22 of the other hub 20 located adjacent to each other, the outer peripheral surface of the main body 21 of the one hub 20 and the other The connecting member 30 is disposed between the projecting portion 22 of the hub 20 and the inner peripheral surface of the extending portion 23 and between the main body portion 21 of one hub 20 and the opposed end surfaces of the main body portion 21 of the other hub 20. A certain clearance for inserting each part is obtained.

  Further, two of the three projecting portions 22 are formed with screw holes 25 penetrating from the outer peripheral surface to the inner peripheral surface of the main body portion 21, and a headless screw 26 is screwed into the inside thereof. Yes. By rotating the headless screw 26 in a predetermined direction from the outside, the front end portion thereof fastens the output shaft 84a of the sewing machine motor 84 inserted into the main body portion 21 or the outer peripheral surface of the upper shaft 85, and these rotational shafts are connected to these rotation shafts. In contrast, the hub 20 is prevented from being pulled out or rotated.

  The connecting member 30 is located next to the six insertion portions 31 arranged in the gap between the protrusions 22 of the two hubs 20 and 20 alternately arranged along the circumferential direction around the rotation center line C. The six connecting portions 32 that alternately connect one end portions and the other end portions in the rotation center line C direction of the insertion portions 31 and 31 and the main body portions 21 and 21 of the two hubs 20 and 20 face each other. A partition wall 33 is provided between the end faces. And these are integrally formed from rubber which is an elastic body, for example, nitrile rubber (NBR).

When the interposition part 31 is arranged to connect the two hubs 20, 20, the side surfaces (side surfaces of both ends in the circumferential direction) of the projection 22 of the adjacent one hub 20 and the other hub 20. It is a plate-shaped body inserted in the clearance between the side surfaces of the protrusions 22 of the above.
The length L (see FIG. 5) of the insertion portion 31 in the direction of the rotation center line C coincides with the entire length of the protrusion 22 including the extension portion 23, and the radius of the insertion portion 31 from the rotation center line C. The width H in the direction (see FIG. 5) matches the diameter difference between the outer peripheral surface of the protrusion 22 of the hub 20 and the outer peripheral surface of the main body 21. Moreover, since the insertion part 31 is compressible by the elasticity, the thickness (angle width) (theta) 2 (refer FIG. 6) in the circumferential direction is set slightly wider than the clearance between each projection part 22. .
Thus, the insertion part 31 can be brought into close contact with the entire side surface of each protrusion 22 at the time of insertion.

When the connecting portion 32 is arranged to connect the two hubs 20, 20, the inner peripheral surface of the extending portion 23 of the protruding portion 22 of one hub 20 and the outer peripheral surface of the main body portion 21 of the other hub 20 are connected. For this reason, it forms in the plate shape curved along these surrounding surfaces.
The connecting portion 32 connects one end portions of the insertion portions 31 and 31 in the direction of the rotation center line C (the connection portion 32 positioned on the left side in FIG. 5) and the rotation center line of the insertion portions 31 and 31. There is one that connects the other ends in the C direction (the connecting portion 32 located on the right side in FIG. 5), and these are alternately arranged along the circumferential direction around the rotation center line C. Yes.

The partition wall portion 33 is a partition wall that is radially inward with respect to the rotation center line C of the six insertion portions 31 and is perpendicular to the rotation center line C provided at an intermediate position in the longitudinal direction of each of the insertion portions 31. A circular opening 33a is formed at the center.
The thickness of the partition wall 33 in the direction of the rotation center line C is obtained by subtracting the length of the main body 21 in the direction of the rotation center line C from the length of the extension 23 of the protrusion 22 of the hub 20 in the direction of the rotation center line C. The value is almost the same. The inner diameter of the opening 33a is set to be equal to or slightly larger than the inner diameter of the main body 21.
Thereby, when it is set as the arrangement which connects two hubs 20 and 20, partition part 33 is in the state where it inserted without a gap between the mutual end surfaces in main-body parts 21 and 21 of each hub 20 and 20. Be placed.

[Coupling work by coupling]
Next, a method of connecting the output shaft 84a of the sewing machine motor 84 and the upper shaft 85 by the coupling 10 will be described with reference to FIG. In the following description, the left hub 20 in FIG. 5 is attached to the upper shaft 85, and the right hub 20 is attached to the output shaft 84 a of the sewing machine motor 84.

First, each hub 20, 20 is attached to the output shaft 84 a and the upper shaft 85 of the sewing machine motor 84.
Specifically, the output shaft 84a of the sewing machine motor 84 is inserted into the center portion of one hub 20, and the headless screw 26 of the screw hole 25 is tightened to fix the one hub 20 to the output shaft 84a.
Similarly, the upper shaft 85 is inserted into the center of the other hub 20, and the other hub 20 is fixed to the upper shaft 85 with the headless screw 26.

Next, the connecting member 30 is attached to the hub 20. In this case, the connecting member 30 may be attached to either the output shaft 84a side or the upper shaft 85 side, but here, a case where the connecting member 30 is attached to the hub 20 on the output shaft 84a side will be described as an example.
First, while extending the extension part 23 of each protrusion part 22 of the hub 20 and the one end part (right end part in FIG. 5) of the connection member 30, the circle of the three connection parts 32 on the one end part side of the connection member 30 is provided. The connecting member 30 is attached to the hub 20 so that the body portion 21 of the hub 20 is inserted into the inner peripheral surface side of the three connecting portions 32 with the circumferential position aligned with the three concave portions 24 of the hub 20. . At this time, the main body portion 21 is inserted inside the three connecting portions 32 until the partition wall portion 33 of the connecting member 30 contacts the end surface of the main body portion 21 of the hub 20 on the output shaft 84a side.
As a result, the inner peripheral surfaces of the three connecting portions 32 on the one end portion (right end portion in FIG. 5) side of the connecting member 30 and the outer peripheral surface of the main body portion 21 of the hub 20 on the output shaft 84a side are in close contact. The outer peripheral surfaces of the three connecting portions 32 on the other end portion (left end portion in FIG. 5) side and the inner peripheral surfaces of the three extending portions 23 of the hub 20 on the output shaft 84a side are in close contact with each other.

Then, the hub 20 on the output shaft 84a side to which the connecting member 30 is attached is connected to the hub 20 on the upper shaft 85 side. In this case, the extension 23 of each projection 22 of the hub 20 on the output shaft 84a side and the extension 23 of each projection 22 of the hub 20 on the upper shaft 85 side face each other. The position of the projecting portion 22 in the circumferential direction of the extending portion 23 is matched with each concave portion 24 of the counterpart hub 20, and each extending portion 23 interposes each connecting portion 32 of the connecting member 30. The hub 20 on the output shaft 84 a side and the hub 20 on the upper shaft 85 side are coupled together with the sewing machine motor 84 so as to be inserted into the concave portion 24 of the counterpart hub 20. Also in this case, the hub 20 on the output shaft 84a side is moved toward the hub 20 on the upper shaft 85 side until the partition wall portion 33 of the connecting member 30 contacts the end surface of the main body portion 21 of the hub 20 on the upper shaft 85 side.
As a result, the inner peripheral surface of the three connecting portions 32 on the other end portion (left end portion in FIG. 5) side of the connecting member 30 and the outer peripheral surface of the main body portion 21 of the hub 20 on the upper shaft 85 side are in close contact. The outer peripheral surfaces of the three connecting portions 32 on the one end portion (right end portion in FIG. 5) side of the 30 and the inner peripheral surfaces of the three extending portions 23 of the hub 20 on the upper shaft 85 side are in close contact with each other.

Thereby, the coupling 10 is assembled and the output shaft 84a of the sewing machine motor 84 and the upper shaft 85 are connected. In parallel with the connection work by the coupling 10, the work for installing the sewing machine motor 84 on the motor mounting base 93 is also performed.
In the above example, each hub 20 of the coupling 10 is first attached to the output shaft 84a and the upper shaft 85 of the sewing machine motor 84, but the work procedure is not limited to this. For example, first, the hub 20 and the connecting member 30 of the coupling 10 are first assembled, and then one hub 20 is attached to either the output shaft 84a or the upper shaft 85 of the sewing machine motor 84, and then the other hub. 20 may be attached to either the output shaft 84 a or the upper shaft 85 of the sewing machine motor 84.

[Technical effects of coupling]
The effects of the coupling 10 will be described in comparison with the couplings 100 and 200 of FIGS.
In the coupling 10, since the protrusions 22 of the hubs 20 are provided with the extending parts 23, the protrusions 22 are connected to the entire length of the coupling 10 (the length when the two hubs 20 and 20 are connected via the connecting member 30. It is possible to align the length to the same length.
Accordingly, the width of the contact surface between the protrusion 22 of the hub 20 and the insertion portion 31 of the connecting member 30 in the direction of the rotation center line C can be expanded to the maximum by matching the overall length of the coupling 10. Even when the coupling 10 is downsized, the load per unit area in the insertion portion 31 of the connecting member 30 can be sufficiently reduced.

  On the other hand, the coupling 100 has a structure in which the protrusions 112 and 122 of the hubs 110 and 120 protrude from the main body parts 111 and 121 in the direction of the rotation center line. The width of the contact surface in the direction of the rotation center line C can be ensured only up to the protruding length of the protrusions 112 and 122 of the hubs 110 and 120. For this reason, the contact area between the protrusions 112 and 122 and the protrusion 132 is smaller than the total length of the coupling 100, and the load per unit area of the protrusion 132 of the connecting member 130 when the coupling 100 is downsized. Can not be reduced.

  In addition, the coupling 200 has a width in the direction of the rotation center line C of the contact surface between the protrusions 212 and 222 of the hubs 210 and 220 and the insertion part 231 of the connecting member 230 up to a width of the hub 220 in the direction of the rotation center line. Can only be ensured. For this reason, also in the case of the coupling 200, the contact area between the protrusions 212 and 222 and the insertion portion 231 is reduced with respect to the entire length thereof, and when the coupling 200 is downsized, the insertion portion 231 of the connecting member 230. The load per unit area cannot be reduced.

As described above, the coupling 10 can sufficiently increase the contact area between the protrusion 22 of the hub 20 and the insertion portion 31 of the connecting member 30 with respect to the entire length thereof. It is possible to improve the durability of the connecting member 30 while being planned.
Furthermore, the selection of the material of the connecting member 30 is not limited to an expensive material that can withstand a high load, so that the manufacturing cost of the coupling 10 can be reduced.

Moreover, since the connection member 30 of the coupling 10 is provided with the connection part 32 which connects each insertion part 31, it is possible to integrate each part and to form with one member. And the connection part 32 is formed in the shape along the outer peripheral surface of the main-body part 21 of the hub 20, while being alternately formed in the one end part side and other end part side of each insertion part 31. As shown in FIG. Therefore, it will be in the state inserted between the main-body part 21 of one hub 20, and the extension part 23 of the other hub 20. FIG. As a result, it is possible to absorb the vibrations in the radial direction when the output shaft 84a and the upper shaft 85 of the sewing machine motor 84 are rotated, and perform good torque transmission.
Further, since the connecting member 30 includes the partition wall 33, the partition wall 33 is inserted between the main bodies 21 of the one hub 20 and the other hub 20, and the output shaft 84 a of the sewing machine motor 84. It is possible to absorb the vibrations in the axial direction when the upper shaft 85 rotates and perform good torque transmission.

[Modification of coupling (1)]
FIG. 7 is an exploded perspective view of a first modification of the coupling. The coupling 10A can be the same as the coupling 10 except for the connection member 30A.
The coupling member 30A of the coupling 10A includes six insertion portions 31 that are the same as the coupling member 30, and one end portions and the other end portions of the adjacent insertion portions 31 and 31 in the rotation center line C direction. Six connection portions 32 </ b> A that are alternately connected and partition portions 33 that are the same as the connection members 30 are provided. The connecting member 30A is also integrally formed from rubber which is an elastic body, for example, nitrile rubber (NBR).
And each said connection part 32A is formed in the shape along the end surface of the extension end part of the extension part 23 of the hub 20 in the one end part or other end part of the two insertion parts 31 to connect. Further, the protruding length of each extending portion 23 is shortened by the thickness of the connecting portion 32A, and the end surface of the connecting portion 32A on the side not facing the extending portion 23 coincides with the end surface of the main body portion 21 of the hub 20. It is preferable to make it.
For this reason, when connecting the hub 20 and the hub 20 with the connecting member 30 </ b> A interposed therebetween, the connecting portions 32 </ b> A are in close contact with the end surfaces of the extending portions 23. In this case, since the connecting portion is not inserted between each extending portion 23 and the main body portion 21, the clearance can be reduced, and the entire coupling 10A can be downsized in the radial direction.

  As described above, the coupling 10A can have the same configuration as the hub 20 of the coupling 10 other than the connecting member 30A, for example, the hub 20 of the coupling 10, but the extension of one hub 20 can be used. Since the clearance between the portion 23 and the main body portion 21 of the other hub 20 is not required, the clearance does not occur, or the protruding length of each extending portion 23 is equal to the thickness of the connecting portion 32A. It goes without saying that design changes such as shortening may be made.

[Modification of coupling (2)]
FIG. 8 is a perspective view of a second modification of the coupling. The coupling 10B may be the same as the coupling 10 except for the connecting member 30B.
In the coupling member 30B of the coupling 10B, six insertion portions 31B that are inserted between the projections 22 of the two hubs 20 and 20 are individually separated, and the coupling portion 32 and the partition wall portion 33 are provided. Not.
Each insertion portion 31B is fixed to one or both of the two opposing side surfaces of the adjacent protrusions 22 and 22 by bonding, baking, or the like in the manufacturing process of the coupling 10B.
When fixed to one side surface of each protrusion 22, each insertion portion 31 </ b> B cannot be separated from the hub 20. Moreover, when it adheres to the two side surfaces of each protrusion part 22, the two hubs 20 and 20 and the connection member 30B cannot be integrated and isolate | separated.
For this reason, although the output shaft 84a and the upper shaft 85 of the sewing machine motor 84 are connected with the coupling 10B integrated, there is no work problem.
Thus, by separating each insertion part 31B individually and fixing it to the hub 20 in advance, the structure of the connecting member 30B is simplified, so that the productivity of the coupling 10B can be improved. Become.

  The same coupling 10B as the hub 20 of the coupling 10 can be used, but a clearance between the extension 23 of one hub 20 and the main body 21 of the other hub 20 is unnecessary. Therefore, a design change such as preventing the clearance from occurring or shortening the protruding length of each extending portion 23 so that the main body portions 21 are closer to each other because the partition portion 33 is not interposed. Needless to say, you can go.

[Modification of coupling (3)]
FIG. 9 is a perspective view of a third modification of the coupling. This coupling 10C can be the same as the coupling 10 except for the hub 20C.
In the coupling 10 described above, the length of the extending portion 23 of each hub 20 in the direction of the rotation center line C is set to be substantially equal to the length of the main body portion 21, whereby the total length of the protruding portion 22 = the coupling 10. The total length is. By matching these lengths, the contact area between the protrusion 22 and the insertion part 31 can be maximized with respect to the size of the coupling 10.
On the other hand, the extension part 23C of each hub 20C of the coupling 10C is set to have a shorter length in the direction of the rotation center line C than the main body part 21. Therefore, the total length of the projection 22 is less than the total length of the coupling 10, and the contact area between the projection 22 and the insertion portion 31 is not expanded to the maximum with respect to the size of the coupling 10. For this reason, the coupling 10 </ b> C is inferior to the coupling 10 in the effect of reducing the load per unit area in each insertion portion 31. However, since the entire length of the protrusion 22C is made longer than the main body 21 by at least the extending portion 23C, compared with the conventional couplings 100 and 200 (see FIGS. 11 and 12), The load per unit area is reduced, and the life of the connecting member 30 can be extended.

  As described above, the coupling 10C can be the same as the coupling member 30 of the coupling 10 except for the configuration other than the hub 20C, for example, the coupling member. Design changes such as shortening the insertion portion 31 so that the projection 22C of one hub 20C and the projection 22C of the other hub 20C located adjacent to the insertion portion 31 are the same as the overlapping range in the direction of the rotation center line C. Needless to say, you can go.

[Others]
Each of the couplings 10 to 10C described above is based on the assumption that the output shaft 84a and the upper shaft 85 of the sewing machine motor 84 have the same outer diameter, and the same hub 20 or 20C is attached to each. Needless to say, when the outer diameters of the output shaft 84a and the upper shaft 85 of the motor 84 are different, hubs having corresponding inner diameters may be attached. In that case, it is desirable to use a hub that differs only in the inner diameter of the through hole for inserting the shaft located at the center of each hub.

  The hub 20 is attached to the output shaft 84a or the upper shaft 85 of the sewing machine motor 84 using the headless screw 26. However, the present invention is not limited to this. For example, the key groove is formed between the output shaft 84a or the upper shaft 85 and the hub 20. It may be attached by forming a key and inserting a key. A combination of a key and a screw may be used.

  Further, the protrusions 22 and 22C of the hubs 20 and 20C of the couplings 10 to 10C described above are formed so that both side edges in the circumferential direction are parallel to the rotation center line direction C. Not limited to this, the side edges in the circumferential direction of the protrusions 22 and 22C may be tapered so that the width becomes narrower toward the distal end side of the extension parts 23 and 23C.

FIG. 10 shows that when the coupling 10 and the coupling 200 are provided between the output shaft 84a and the upper shaft 85 of the sewing machine motor 84 that transmits torque under the same conditions, It is the graph which showed the calculation result of the load per unit area (stress) added to a contact surface.
In these couplings 10 and 200, the maximum radius and the minimum radius from the rotation center line C of the contact surface between the protrusion and the insertion portion are the same value, and the rotation center line C of the coupling 10 and 200 is assumed to be the same. The total length in the direction is assumed to be the same value. When a torque is intensively generated between the pair of projections 21 and 21 among the three projections 22 of the one hub 20 and the three projections 22 of the other hub 20 during torque transmission. The stress was calculated assuming that
As a result, the stress value on the contact surface of the coupling 10 was 7.3 [MPa], and the stress value on the contact surface of the coupling 200 was 17.4 [MPa].

Moreover, the safety factor in each coupling 10,200 was calculated based on the stress calculation.
The safety factor was calculated from [allowable stress value in each coupling 10, 200] / [stress value in each coupling 10, 200 under normal use conditions in the sewing machine 80].
As a result, the safety factor for the coupling 10 was 2.0, and the safety factor for the coupling 200 was 0.8.
As described above, in the first embodiment, it is possible to obtain the result that the inventive coupling 10 reduces the stress generated in the protrusion 22 and improves the safety factor compared to the conventional coupling 200. It was.

10, 10A, 10B, 10C, 100, 200 Coupling 20, 20C Hub (fixed body)
21 Body 22, 22 C Protrusion 23, 23 C Extension 24 Recess 30, 30 A, 30 B Connection member 31, 31 B Insertion 32, 32 A Connection 33 Bulkhead 80 Sewing machine 84 Sewing motor 84 a Output shaft (rotating shaft)
85 Upper shaft (rotating shaft)

Claims (5)

Two fixed bodies individually fixed to the two rotating shafts;
In a coupling comprising a connecting member made of an elastic body inserted between these fixed bodies,
The two fixed bodies include a cylindrical main body portion into which the individual rotation shafts are inserted, and a rotation center line of the rotation shaft formed in a plurality at equal intervals in the circumferential direction on the outer peripheral surface of the main body portion. And having a protruding portion of ridges formed along the direction,
The plurality of protrusions are formed over the entire length of the main body portion in the rotation center line direction, and include an extension portion formed to protrude from one end portion of the main body portion along the rotation center line direction,
In the state in which the two fixed bodies are inserted into the plurality of extending portions of the other fixed body where the protrusions are alternately arranged along the circumferential direction and the main bodies are connected to each other. Concatenated,
The connecting member includes a plurality of insertion portions arranged in a plurality of gaps of the protruding portions alternately arranged along the circumferential direction,
The length of the rotation center line direction of the plurality of insertion portions is equal to the total length of the protrusions.   The coupling according to claim 1, wherein the total length of the protrusions of the two fixed bodies in the rotation center line direction is equal to the length of the two fixed bodies when they are connected via the connecting member.   The connecting member surrounds one end and the other end in the rotation center line direction of two adjacent insertion portions among the plurality of insertion portions arranged along the circumferential direction. The coupling according to claim 1, further comprising a plurality of connecting portions that are alternately connected in a direction.   The coupling according to claim 3, wherein the connecting portion of the connecting member has a shape along the distal end surface while passing the distal end surface in the extending direction of the extending portion of the fixed body.   The connecting part of the connecting member has a shape along the outer peripheral surface of the main body part of the other fixed body while passing between the extending part of the one fixed body and the main body part of the other fixed body. The coupling according to claim 3.

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