SHAFT COUPLING

Abstract: A shaft coupling wherein a plurality of first grooves (10) in a direction Y are formed in a flange poriton (3) at an end of a prime mover shaft; a plurality of second grooves (12) in a direction X are formed in a flange portion (5) at an end of a follower shaft; a turning force transmitting member (14) is interposed between the flange portion (3) at the end of the prime mover shaft and the flange portion at the end of the follower shaft; the turning force transmitting member (14) is provided with a plurality of first sliding slat portions (16) slidably fitted in the first grooves and further provided with a plurality of second sliding slat portions (18) slidably fitted in the second grooves; the turning force transmitting member (14) is made of plastics; and the flange portion (3) at the end of the prime mover shaft and the flange portion (5) at the end of the follower shaft are made of metal. By use of this shaft coupling, the eccentricity and an angle of deviation between movements in a thrust direction of the prime mover shaft and the follower shaft can be satisfactorily accommodated, so that a high turning force can be transmitted smoothly with a low loss.

Description: The present invention relates to a shaft coupling which excellently copes with eccentricity, deviation of angle and axial movement between a driving shaft and a driven shaft so that a large torque is smoothly transmitted with a small loss and allows its maintenance to be simplified. In various mechanisms for transmitting a rotational torque, the end portions of two rotating shafts are coupled by means of a coupling. For example, an output rotating shaft of a motor and an input rotating shaft of a pump are coupled to each other by means of the coupling. In this case, it takes a considerable amount of labor to carefully install the motor and the pump so that the output shaft of the motor and the input shaft of the pump may satisfactorily align. In addition, even if they are installed by paying a full attention to assuring such an alignment, some eccentricity or deviation of angle remains between both the shafts and, further, since vibrations occur in the motor and the pump during the operation, a flexible coupling has conventionally been used as the coupling in order to absorb them by the coupling portion. As the conventional coupling, ones using a flexible member such as a spring, wire or the like may be enumerated by way of example. However, with those flexible couplings, when the eccentricity, deviation of angle and axial movement occur, since the absorption of a relative displacement between the two rotating shafts is assigned only to a deformation of the flexible member, in order to enlarge an extent to which the eccentricity, deviation of angle and axial movement are allowed, the deformation of the flexible member must be large. In consequence, a soft member must be used as the flexible member and, especially when a large torque is transmitted, the torque cannot excellently be transmitted during a transition period when an equilibrium state is being changed. In addition, a considerable amount of energy is consumed to deform the flexible member, and an efficiency of transmitting the torque is lowered. In addition, an Oldham coupling has been used as a coupling which copes with the above-described eccentricity, deviation of angle and axial movement. An example of an Oldham coupling is disclosed in document DE-C-913117. The pre-characterizing clause of claim 1 is based on this document. The known shaft coupling comprises the channels and slide members which are engaged with each other. Due to the sliding motion between the lateral surfaces of the channels and the slide members, heat is generated during operation of the shaft coupling. This heat tends to be accumulated on a base plate which connects the slide members of the transmitting member of the known shaft coupling, with the result that the temperature of the torque transmitting member is so increased as to lower the strength. In order to cope with this problem, a comparatively thick base plate is required which increases the length of the shaft coupling in the axial direction. It is an object of the present invention to provide a compact and yet highly effective shaft coupling. This object is achieved by the shaft coupling according to claim 1, and in particular by the openings which extend through the torque transmitting member between the adjacent first slide members and between the adjacent second slide members. In the shaft coupling according to the invention, no base plate like that of the known shaft coupling is used and the openings extending through the transmission member are provided, so that the heat evolving at the first and second slide members is rapidly transferred to the ambient air which flows through the openings. Further developments of the invention are defined in the subclaims. Two embodiments of the present invention will be hereinafter described with specific reference to the accompanying drawings. Fig. 1 is an exploded perspective view illustrating a first embodiment of a shaft coupling according to the present invention; Fig. 2 is a perspective view illustrating how it is assembled; Fig. 3 is a frontal view thereof part of which is omitted; Fig. 4 is a longitudinal cross-sectional view of its central portion; Fig. 5 is a schematic explanatory view illustrating an example embodying the shaft coupling of the invention; Fig. 6 is an exploded perspective view illustrating a second embodiment of the shaft coupling according to the present invention; and Figs. 7 and 8 are respectively a perspective view and a lateral cross-sectional view of the second embodiment illustrating how it is assembled. Referring to Figs. 1 to 4, reference numeral 2 denotes the end portion of a driving shaft, 2' a rotational axis of a driving shaft and 3 denotes a flange portion formed at the top end of the end portion of the driving shaft. In addition, reference numeral 4 denotes the end portion of a driven shaft, 4' a rotational axis of the driven shaft and 5 denotes a flange portion formed at the top end of the end portion of the driven shaft. The end portion 2 of the driving shaft and the end portion 4 of the driven shaft are each disposed so that the flange portions 3 and 5 are opposed to each other and the rotational axes 2' and 4' align with each other in the direction of Z. The end surface of the flange portion 3 at the end portion of the driving shaft, which faces the flange portion 5 at the end portion of the driven shaft, forms a plane (X-Y plane) which intersects at a right angle with the rotational axis 2' of the driving shaft. Similarly, the end surface of the flange portion 5 at the end portion of the driven shaft, which faces the flange portion 3 at the end portion of the driving shaft, forms a plane (X-Y plane) which intersects at a right angle with the rotational axis 4' of the driven shaft. These flange portions 3 and 5 are made of metal, for example, steel. On the flange portion 3 at the end portion of the driving shaft, three first channels 10a, 10b and 10c are each formed in the direction of Y which intersect at a right angle with the above-described direction Z. Likewise, on the flange portion 5 at the end portion of the driven shaft, three second channels 12a, 12b and 12c are each formed in the direction of X which intersect at a right angle with both Z and Y directions. The shape of the cross section of these channels are each of rectangular form. A torque transmitting member 14 is disposed between the flange portions 3 and 5. The transmitting member 14 is formed by joining three first slide members 16a, 16b and 16c and three second slide members 18a, 18b and 18c. The slide members 16a, 16b and 16c are each fitted into the channels 10a, 10b and 10c of the flange portion 3 at the end portion of the driving shaft so that they may be moved in the directions of Y and Z within these channels. Similarly, the slide members 18a, 18b and 18c are each fitted into the channels 12a, 12b and 12c of the flange portion 5 at the end portion of the driven shaft so that they may be moved in the directions of X and Z within these channels. However, a protrusion 15 is formed on the slide members 16b and 18b so that they each abut on the bottom portion of the channel 10b at the side of the driving shaft and the bottom portion of the channel 12b at the side of the driven shaft, to thereby set an interval between the end portion 2 of the driving shaft and the end portion 4 of the driven shaft with the result that a limit is provided for them to move in the direction of Z. Incidentally, according to this embodiment, the torque transmitting member 14 is integrally formed of plastic material. As the plastic material, a synthetic resin which has a proper slipping property relative to the metallic material of the flange portions 3 and 5, a proper stiffness and, further, a proper flexibility, for example, a polyacetal resin or a polyamide resin may be used. In addition, the plastic material of the transmitting member 14 exhibits self-lubricating properties, and may continuously lubricate especially when being in contact with the lateral surface of the channel 10 of the flange portion 3 and the lateral surface of the channel 12 of the flange portion 5. The transmitting member 14 may be produced by, for example, machining a block of the plastic material. In this embodiment, when the end portion 2 of the driving shaft is rotated, its torque is transmitted via the slide members 16a through 16c and the slide members 18a through 18c of the transmitting member 14 to rotate the end portion 4 of the driven shaft. At this time, a certain deformation is allowed for the slide members 16a through 16c and 18a through 18c of the transmitting member 14. If the rotational axis 2' of the driving shaft and the rotational axis 4' of the driven shaft becomes eccentric, then it can be successfully coped with by mainly a sliding motion of the slide members 16a through 16c within the channels 10a through 10c and a sliding motion of the slide members 18a through 18c within the channels 12a through 12c. In addition, if the rotational axis 2' of the driving shaft and the rotational axis 4' of the driven shaft deviate in angle, then it can be successfully coped with by mainly the sliding and rocking motions (the ununiform movement in the direction of the rotational axis 2' of the driving shaft, that is, the rotational movement with the X direction as its axis) of the slide members 16a through 16c within the channels 10a through 10c and the sliding and rocking motions (the ununiform movement in the direction of the rotational axis 4' of the driven shaft, that is, the rotation with the Y direction as its axis) of the slide members 18a through 18c within the channels 12a through 12c. Further, when the end portion 2 of the driving shaft and the end portion 4 of the driven shaft are relatively moved axially, it can be successfully coped with by a parallel movement of the slide members 16a through 16c in the direction of Z within the channels 10a through 10c and a parallel movement of the slide members 18a through 18c in the direction of Z within the channels 12a through 12c. Actually, the above-described eccentricity, deviation of angle and axial movement can be generated in combination and, therefore, a combination of these actions is carried out. In this embodiment, since the torque transmitting member 14 is somewhat flexible, a slight deformation can be generated to it. Incidentally, since the magnitude of the above-described eccentricity, deviation of angle and axial movement is substantially restricted to a certain range, it cannot happen that, by the above-described actions, the slide members 16a through 16c and the slide members 18a through 18c of the transmitting member 14 is released from the channels 10 and 12 or each portion of the transmitting member 14 is deformed by exceeding a permissible range. As described above, according to this embodiment, three kinds of deformations and displacements such as a slight deformation of the transmitting member 14, the movement of the slide members 16a through 16b within the channels 10a through 10c and the movement of the slide members 18a through 18c within the channels 12a through 12c are simultaneously achieved and, as a result, a deformation and a displacement of desired magnitude can be achieved on the whole even if each of them is small, so that the transmission of the torque can be especially excellently achieved during the transition period when the equilibrium state is being changed. In addition, in this embodiment, since the transmitting member 14 made of synthetic resin is used, the effect of damping the vibration and suppressing its transmission is also excellent. The shaft coupling according to the embodiment as above can be readily produced by assembling the construction members as shown in Fig. 1. Since this embodiment is not only based on the deformation of the flexible member as being different from a conventional flexible coupling, the loss of energy is small and the effect of transmitting the torque is excellent. In addition, since the torque transmitting member 14 has a plurality of first and second slide members respectively so that they may transmit the torque by contacting the first and second channels over a large area, a large torque can be transmitted. That is, since the numbers of the first slide members and the second slide members are three, a great torque can be transmitted. In addition, in this embodiment, since the transmitting member 14 has a proper flexibility, transmission of the vibration between the driving shaft side and the driven shaft side can be suppressed while, at the same time, transmission of the torque can be smoothly changed as the load is abruptly changed or the like. In addition, according to this embodiment, since the transmitting member 14 displays self-lubricating properties when sliding on the flange portion 3 at the end portion of the driving shaft and the flange portion 5 at the end portion of the driven shaft, it is not necessary to use a lubricating oil, which eases a maintenance. Fig. 5 is a schematic explanatory view illustrating an embodiment in which the shaft coupling according to the present invention is used. The end portion 2 of the driving shaft for the shaft coupling C according to the present invention is mounted to an output rotating shaft M' of a motor M (the shaft M' corresponds to the driving shaft), and the end portion 4 of the driven shaft for the shaft coupling C is mounted to an input rotating shaft P' of a pump P, which is the driven apparatus (the shaft P' corresponds to the driven shaft). When the shaft coupling C is mounted, the motor M is set and fixed, and the end portion 2 of the driving shaft of the shaft coupling C is connected and fixed to the output shaft M' of the motor so that, as shown in Fig. 4, a protrusion 15 at both sides of the transmitting member 14 abuts on the bottom portion of the channel of the flange portion 3 at the end portion of the driving shaft while abutting on the bottom portion of the channel of the flange portion 5 at the end portion of the driven shaft. Then, the pump P is gradually moved toward the shaft coupling C to join and fix the input shaft P' of the pump to the end portion 4 of the driven shaft of the shaft coupling C. Incidentally, at this time, it is not necessary to strictly carry out removal of the eccentricity, removal of the deviation in angle and adjustment of the axial direction between the driving shaft and the driven shaft. Fig. 6 is an exploded perspective view illustrating a second embodiment of the shaft coupling according to the present invention, and Figs. 7 and 8 are respectively a perspective view and a lateral cross-sectional view illustrating how it is assembled. In these figures, like signs are assigned to the members having a function similar to that of the above-described embodiment. In this embodiment, the flange portion 5 at the end portion of the driven shaft comprises a proximal portion 5' and a plate-shaped fitting member 6. The fitting member 6 is mounted to the proximal portion 5' by means of a screw. An engaging channel 7 is formed in the direction of X on the proximal portion 5', and an engaging protrusion 8 of a shape corresponding to the engaging channel is formed in the direction of X on the above-described fitting member 6. These engaging channel 7 and protrusion 8 each serve as a means for preventing the relative rotation. That is, the relative rotation of the fitting member 6 and the proximal portion 5' about the rotational axis 4' of the driven shaft is blocked not only by means of the screw, but substantially by engagement of the engaging channel 7 and the engaging protrusion 8. And, on the surface of the fitting member 6 at the side facing the flange portion 3 at the end portion of the driving shaft, a plurality of second channels 12 are formed in the direction of X, the cross section of which is of rectangular form. The torque transmitting member 14 is disposed between the flange portion 3 at the end portion of the driving shaft and the flange portion 5 at the end portion of the driven shaft. The transmitting member has a plurality of first slide members 16 at the side facing the driving shaft, which are each fitted to the plurality of first channels 10, while having a plurality of second slide members 18 at the side facing the driven shaft, which are each fitted to the plurality of second channels 12. Thus, also according to the present invention, a function similar to that of the first embodiment can be achieved. The entire shaft coupling and part of the construction members therefor according to this embodiment can be readily mounted to and removed from a mechanism for transmitting the torque. That is, for example, when they are repaired, by removing the screw, the fitting member 6 can be relatively moved in the direction of X relative to the proximal portion 5' of the flange portion 5 at the end portion of the driven shaft. In addition, since the fitting member 6 can be relatively moved in the direction of X relative to the transmitting member 14, after all, the fitting member 6 can be withdrawn by moving in the direction of X. The transmitting member 14 can be withdrawn by moving in the direction of Y relative to the flange portion 3 at the end portion of the driving shaft. Thus, by utilizing a space formed in the center, the end portion 2 of the driving shaft and the end portion 4 of the driven shaft 4 can be each further removed. Therefore, according to this embodiment, by removing the worn parts to be replaced, as described above, and mounting new parts in that place in accordance with the opposite procedure as the above-described one, it is promptly repaired without moving at all both of the apparatus at the side of the driving shaft and the apparatus at the side of the driven shaft, which are each connected by the shaft coupling, which may extremely shorten the shut-down time. The process in the initial installation and the final removal of the shaft coupling is completely the same as its repairing.

Claims: Shaft coupling in which: the end portion (2) of a driving shaft and the end portion (4) of a driven shaft are opposedly disposed and a torque transmitting member (14) is interposed between said end portions of the driving shaft and the driven shaft; a plurality of first channels (10, 10a, 10b, 10c) are each formed at said end portion (2) of the driving shaft and extend in a first direction within a plane intersecting at a right angle with the rotational axis of the driving shaft, and a plurality of first slide members (16, 16a, 16b, 16c), which each fit with said first channels (10, 10a, 10b, 10c) of the end portion (2) of the driving shaft, are formed on said transmitting member (14); and a plurality of second channels (12, 12a, 12b, 12c) are each formed at said end portion (4) of the driven shaft and extend in a second direction within a plane intersecting at a right angle with the rotational axis of the driven shaft, and a plurality of second slide members (18, 18a, 18b, 18c), which each fit with said second channels (12, 12a, 12b, 12c) of the end portion (4) of the driven shaft, are formed on said transmitting member (14); wherein said torque transmitting member (14) is integrally formed of plastic material, characterized in that a lateral surface of said first channels (10, 10a, 10b, 10c) of said end portion (2) of the driving shaft and a lateral surface of said second channels (12, 12a, 12b, 12c) of said end portion (4) of the driven shaft are each made of metal; and in that said first slide members (16, 16a, 16b, 16c) and said second slide members (18, 18a, 18b, 18c) of said torque transmitting member (14) are connected one to the other so as to form openings which extend through said torque transmitting member (14) and which are positioned between adjacent first slide members (16, 16a, 16b, 16c) and between adjacent second slide members (18, 18a, 18b, 18c). Shaft coupling as set forth in claim 1, wherein at least one of said end portion (2) of the driving shaft and said end portion (4) of the driven shaft includes a removable fitting member (6) having said first channels (10) or said second channels (12), said fitting member of the end portion of the driving shaft being mounted to the proximal portion of the end portion of the driving shaft in such a way that, when removed, it may be relatively moved in said first direction, and the fitting member (6) of the end portion (4) of the driven shaft being mounted to the proximal portion of the end portion of the driven shaft so that, when removed, it may be relatively moved in said second direction. Shaft coupling as set forth in claim 2 wherein a means (7, 8) for preventing the relative rotation between said fitting member (6) and said proximal portion about the rotational axis is provided at each of said end portions (2, 4) of the driving shaft and the driven shaft. Shaft coupling as set forth in one of claims 1 to 3 wherein said first and second directions intersect at a right angle with each other.

Inventors: KURIBAYASHI SADATOMO, KURIBAYASHI, SADATOMO, KURIBAYASHI, SADATOMO, 21-22, KAKINOKIZAKA
Applicants: K SEVEN KK, KAY SEVEN CO., LTD.
Application year: 1991
Main classification: F16D3
IPC codes: F16D3