JP2009162364A - Rotating shaft coupling - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a low-cost rotating shaft coupling which does not generate noises and capable of absorbing at least rotation errors and axial-direction errors and accurately transmitting the rotation of one shaft to the other shaft. <P>SOLUTION: The rotating shaft coupling 1 transmits the rotation of one shaft to the other shaft by making an outer surface 6 of a square column provided for one of the two facing shafts 1a, 1b contact with an inner surface 7 of a square cylinder provided for the other shaft. The rotating shaft coupling 1 is characterized by a circumferential-direction projecting part 8 formed over the whole circumference of an axial-direction middle part of either the square column outer surface 6 or the square cylinder inner surface 7 so as to project to and contact with the other, which absorbs the rotation error and the axial-direction error between at least the two shafts and transmits the rotation. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a rotary shaft joint, and more particularly to a rotary shaft joint suitable for transmitting rotation between rotary shafts arranged so that shaft end portions are opposed to each other.

  In general, a rotary shaft joint is used to smoothly transmit the rotation between the rotary shafts that may be opposed to each other with the shaft center shifted.

  In a conventional rotary shaft joint, a male and female member, each having a non-circular cross section at the shaft end of the drive shaft and the driven shaft, are loosely fitted to each other so as to have a gap therebetween to transmit the rotation. As a result, the rotation of the drive shaft and the driven shaft is absorbed by absorbing the shift of the shaft center and the angular shift. Furthermore, the inner surface of the female member is formed in a taper shape that spreads outward to ensure absorption of angular deviation (for example, see Patent Document 1).

JP 2001-227556 A

  In the rotary shaft joint disclosed in Patent Document 1, the male and female members of the drive shaft and the driven shaft are loosely fitted to each other so that there is a gap between them, so that unevenness in the transmitted rotational speed occurs. As a result, the rotation cannot be accurately transmitted. Also, if the inner surface of the female member is tapered, if the drive shaft and the driven shaft are displaced away from each other in the longitudinal direction of the shaft, the mating state of the male and female members becomes loose and rotation transmission becomes impossible. There was an inconvenience.

  The present invention has been made in view of these problems, and the rotation of one shaft can be accurately transmitted by absorbing at least the rotation error and the axial error with respect to the other shaft, An object of the present invention is to provide a rotary shaft coupling that does not generate noise and is low in cost.

  In order to achieve the above-described object, the rotary shaft coupling according to the first aspect of the present invention includes a rectangular prism outer surface provided on one of two opposing shafts, and an inner surface of a rectangular tube provided on the other shaft. In the rotary shaft coupling that transmits the rotation of the one shaft to the other shaft by contacting the shaft, over the entire circumference in the vicinity of the intermediate portion in the axial direction of one of the outer surface of the rectangular column and the inner surface of the rectangular tube, A circumferential protrusion that protrudes toward the other and abuts the other is formed with a circumferential protrusion that absorbs at least the rotation error between the two shafts and the axial error and transmits the rotation. It is characterized by.

  According to the present invention thus formed, the circumferential protrusion formed over the entire circumference in the vicinity of the axial intermediate portion of either one of the outer surface of the rectangular column and the inner surface of the rectangular tube of the opposing shaft is By abutting on the outer surface of the quadrangular column or the inner surface of the rectangular cylinder, it is possible to absorb the rotation error and the axial error between at least two axes and transmit the rotation accurately.

  The rotary shaft coupling according to claim 2 is characterized in that the circumferential protrusion and the outer surface of the quadrangular column or the inner surface of the quadrangular cylinder that abuts the circumferential protrusion are in close contact with each other.

  According to the present invention formed in this way, the circumferential protrusion and the rectangular column outer surface or the rectangular cylinder inner surface that abuts against this are in contact with each other in a tightly fitted state, so that the two shafts can be more reliably connected. The rotation error and the axial direction error can be absorbed and the rotation can be accurately transmitted. Since there is no rotation error, noise during rotation transmission can be suppressed to an extremely low level.

  Further, in the rotary shaft coupling according to claim 3, a surface connected to the front and rear in the axial direction of the circumferential protrusion is a tapered surface having the circumferential protrusion as a maximum protrusion. .

  According to the present invention formed as described above, the outer surface of the quadrangular prism and the inner surface of the rectangular tube can be varied with the circumferential protrusion as a fulcrum, and the angular deviation between the two axes can be absorbed. The rotation can be transmitted accurately.

  Further, in the rotary shaft coupling according to claim 4, the outer surface of the quadrangular column of the resin-made coupling cap is such that the circumferential protrusion is press-fitted and fixed to the outer circumferential surface on the shaft end side of the one shaft. It is characterized in that it is integrally formed.

  According to the present invention formed as described above, one shaft having the outer surface of the quadrangular prism can be formed with a resin joint cap, so that it is easy to form the circumferential protrusion and the cost is reduced. The generation of noise can be prevented by the resin.

  Further, in the rotary shaft joint according to claim 5, the joint cap includes a cap-shaped main body portion having the inner peripheral surface and the quadrangular prism outer surface, and a flange formed at an opening of the main body portion. And is formed by injecting resin from a gate formed at the axial center of the top of the main body.

  According to the present invention formed as described above, since the joint cap is formed by injecting resin from the gate formed at the axial center position of the top of the main body, the joint cap can be formed without forming the weld mark of the resin. It is possible to form a joint cap with excellent strength that can be formed and has no stress concentration. Further, the flange portion prevents dust from entering the press-fit portion between the joint cap and the shaft.

  As described above, the rotary shaft coupling of the present invention is constructed and operates, and therefore, the rotation of one rotary shaft is accurately transmitted by absorbing at least the rotation error and the axial error with respect to the other rotary shaft. In addition, it is possible to exhibit excellent effects such as that no noise is generated and the cost can be reduced.

  Hereinafter, embodiments of the rotary shaft coupling of the present invention will be described with reference to FIGS.

  1 to 5 show an embodiment of the rotary shaft coupling of the present invention.

  As shown in the drawings, the rotary shaft joint 1 of the present embodiment transmits rotation between the opposed rotary shafts 1a and 1b.

  In the present embodiment, one rotating shaft 1a is formed by press-fitting a cap-like joint cap 4 into the output shaft 3 of the motor 2, for example. The other rotating shaft 1b is formed by a pipe-like connecting shaft 5 that transmits the rotation of the output shaft 3 to, for example, a gear box (not shown).

  In the rotary shaft joint 1 of the present invention, the outer surface of the quadratic prism provided on one of the two rotating shafts 1a and 1b that are opposed to each other is brought into contact with the inner surface of the square cylinder provided on the other shaft. The rotation of one shaft absorbs at least the rotation error and the axial error between the two shafts with respect to the other shaft to transmit power.

  Therefore, in the present embodiment, the cap body 4a of the joint cap 4 that forms the rotating shaft 1a has the rectangular column outer surface 6, and the shaft end of the pipe-shaped connecting shaft 5 that forms the rotating shaft 1b. The part 5 a has a rectangular cylinder inner surface 7.

  The one joint cap 4 will be described. The joint cap 4 is made of resin, has a quadrangular prism outer surface 6 on the outside, and a cap-shaped main body portion having a mounting hole 4b attached to the output shaft 3 on the inside. 4a and a flange 4c formed at the opening of the mounting hole 4b.

  The mounting hole 4b has a rectangular cross section, and is fixed to the shaft end portion 3a of the output shaft 3 by press-fitting the shaft end portion 3a of the output shaft 3 having the same quadrangular cross section. By making the section of the mounting hole 4b and the shaft end portion 3a of the output shaft 3 a quadrangle (the cross section may be a polygon, for example, a hexagon or an octagon may be used), the rotation of the output shaft 3 is a 100% joint. It can be transmitted to the cap 4. Further, if the torque can be transmitted to the joint cap 4 in accordance with the magnitude of the rotational torque from the output shaft 3, the cross section of the mounting hole 4b and the shaft end 3a may be circular. .

  The rectangular cap outer surface 6 of the joint cap 4 protrudes toward the inner surface 7 of the square cylinder formed on the other rotating shaft 1b over the entire circumference of the intermediate portion of the axial length of the joint cap 4. The circumferential protrusion 8 that contacts is integrally formed. The circumferential protrusion 8 and the inner surface 7 of the rectangular tube that abuts the circumferential protrusion 8 are formed to have a size that abuts in a tightly fitted state. Due to the tight fit between the circumferential protrusion 8 and the inner surface 7 of the rectangular cylinder 7, the circumferential protrusion 8 can absorb rotation errors and axial errors between at least two rotating shafts 1a and 1b and transmit the rotation. . Specifically, the shaft core of the inner surface 7 of the square tube and the shaft core of the circumferential protrusion 8 are in contact with each other without being displaced, and the contact portion between the inner surface 7 of the square tube and the circumferential protrusion 8 is the inner surface 7 of the square tube. Even if they move relative to each other in the axial direction, the contact state between the two remains unchanged. Further, the connecting surfaces 8a and 8b connected to the front and rear in the axial direction of the circumferential protrusion 8 are tapered surfaces having the circumferential protrusion 8 as a maximum protrusion. Since the connecting surfaces 8a and 8b are tapered with respect to the axial center line in this way, the rectangular column outer surface 6 and the rectangular tube inner surface 7 are connected to each other at the connecting angle θ (see FIG. 1 (see (b)) can be varied, and the angular displacement between the two axes can be absorbed to transmit the rotation accurately. The circumferential protrusion 8 may be formed on the inner side of the square cylinder 7 and the other square column outer surface 6 may be formed in a flat shape.

  Further, the flange 4c of the joint cap 4 forms a gap between the shaft end portion 3a of the output shaft 3 and exerts a labyrinth effect at the time of rotation so that the joint cap 4 and the output shaft 3 are pressed into the press-fit portion. Prevent entry of dust and oil. Moreover, the motor 2 can also be cooled by providing a fin (not shown) on the flange 4c and adding a blowing function.

  Next, a method for forming the joint cap 4 formed in this way will be described.

  As shown in FIG. 3, the joint cap 4 of the present embodiment is integrated by injection molding by injecting resin into a mold (not shown) from a gate 9 formed at the axial center position of the top of the main body 4a. Molded. When molten resin is injected from the gate 9 formed at the axial center position of the top of the main body 4a in this way, the molten resin is evenly distributed in the circumferential direction from the top of the main body 4a toward the tip of the flange 4c. Since the filling is performed sequentially (from left to right in FIG. 3), the joint cap 4 can be formed without forming a weld mark of resin. Therefore, it is possible to obtain a joint cap 4 having excellent strength without a portion where stress is concentrated. In addition, as a resin for forming the joint cap 4, any resin can be used as long as it is a material that can ensure rigidity capable of transmitting rotation. For example, polyamide (PA9T) or other resin may be used.

  Next, the pipe-shaped connecting shaft 5 that forms the rotating shaft 1b will be described.

  The connecting shaft 5 is made of metal and is formed in a pipe shape having a circular cross section. The shaft end portion 5a is formed in a rectangular tube shape to form a rectangular tube inner surface 7. The inner surface 7 of the rectangular tube is formed to have a size that makes contact with the circumferential protrusion 8 of the joint cap 4 in a tightly fitted state.

  Next, the rotation transmission action of the rotary shaft joint 1 of the present embodiment will be described.

  The rotating shaft 1a press-fits a mounting hole 4b formed to have a square cross section of the resin joint cap 4 into a shaft end portion 3a formed to have a square cross section of the output shaft 3 of the motor 2. Assembled. Thereby, the circumferential protrusion 8 can be easily formed on the rotating shaft 1a, and the cost can be reduced.

  Subsequently, the rectangular cylinder inner surface 7 of the shaft end portion 5a of the connecting shaft 5 is gradually inserted outside the quadratic prism outer surface 6 of the main body portion 4a of the joint cap 4, and the shaft end portion 5a is a circumferential projecting portion of the main body portion 4a. It is inserted until 8 reaches the vicinity of the flange 4c. As a result, the assembly of the rotary shafts 1a and 1b is completed, and the inner surface 7 of the rectangular cylinder 7 and the circumferential protrusion 8 are brought into contact with each other in a tightly fitted state.

  Due to the tight fit between the circumferential protrusion 8 and the inner surface 7 of the rectangular cylinder 7, the circumferential protrusion 8 can absorb rotation errors and axial errors between at least two rotating shafts 1a and 1b and transmit the rotation. . Specifically, the square tube inner surface 7 and the circumferential protruding portion 8 are united into a planar shape (including points and lines) over the entire circumference by tight fitting. The planar combination of the rectangular cylinder inner surface 7 and the circumferential protrusion 8 is always maintained even when the square cylinder inner surface 7 and the circumferential protrusion 8 rotate. As a result, the shaft core of the inner surface 7 of the rectangular cylinder 7 and the shaft core of the circumferential protruding portion 8 are in contact with each other without being displaced, and rotation is transmitted while absorbing a rotation error.

Even if the contact portion between the inner surface 7 of the rectangular tube 7 and the circumferential protrusion 8 moves relative to the axial direction of the inner surface 7 of the square tube, the contact state between the two remains unchanged. Accordingly, the rotation is transmitted by absorbing the axial error. Further, the connecting surfaces 8a and 8b connected to the front and rear in the axial direction of the circumferential protrusion 8 are tapered surfaces having the circumferential protrusion 8 as the maximum protrusion. As a result, the quadratic prism outer surface 6 and the rectangular cylinder inner surface 7 can vary the mutual connecting angle θ with the circumferential protrusion 8 as a fulcrum, and the rotation is accurately performed by absorbing the angular deviation between the two axes. Can be communicated to.

  Further, since the joint cap 4 is made of resin, it can exhibit a vibration damping action by its own elasticity, or can reduce the impact with other members and prevent noise generation during rotation transmission.

  In addition, this invention is not limited to embodiment mentioned above, A various change is possible as needed.

  For example, in the embodiment shown in FIGS. 1 and 2, the joint cap 4 side is the drive side, and the connecting shaft 5 side is the driven side, but the drive side and the driven side can be applied interchangeably. Further, the joint cap 4 may be omitted, and the circumferential protrusion 8 may be formed directly on one of the rotating shafts 1a and 1b. Moreover, although the circumferential direction protrusion part showed what was formed over the perimeter, it may be intermittent.

(A) is sectional drawing which shows embodiment of the rotating shaft coupling which concerns on this invention, (b) is an enlarged view of the (circle) part of (a). 1 is an exploded perspective view of the embodiment shown in FIG. Sectional drawing of the coupling cap of embodiment shown in FIG. Left side view of FIG. Sectional drawing along the AA line of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Rotating shaft coupling 1a, 1b Rotating shaft 4 Joint cap 5 Connecting shaft 6 Square column outer surface 7 Square cylinder inner surface 8 Circumferential protrusion 9 Gate

Claims (5)

Rotation that transmits the rotation of the one shaft to the other shaft by bringing the outer surface of the quadrangular prism provided on one of the two opposing shafts into contact with the inner surface of the square tube provided on the other shaft In the shaft coupling, a circumferential projecting portion that projects toward the other and abuts against the other over the entire circumference in the vicinity of the axial intermediate portion of either one of the outer surface of the rectangular column and the inner surface of the rectangular cylinder, A rotary shaft coupling characterized in that a circumferential protrusion is formed to absorb rotation error and axial error between two shafts and transmit rotation. 2. The rotary shaft joint according to claim 1, wherein the circumferential protrusion and the outer surface of the quadrangular column or the inner surface of the quadrangular cylinder that are in contact with the circumferential protrusion are in close contact with each other. 3. The rotary shaft joint according to claim 1, wherein a surface connected to the front and rear in the axial direction of the circumferential protruding portion is a tapered surface having the circumferential protruding portion as a maximum protruding portion. . The circumferential protrusion is integrally formed on an outer surface of a rectangular column of a resin joint cap in which an inner peripheral surface is press-fitted and fixed to an outer peripheral surface on the shaft end side of the one shaft. The rotary shaft coupling according to any one of claims 1 to 3. The joint cap includes a cap-shaped main body portion having the inner peripheral surface and the outer surface of the quadrangular prism, and a flange formed at an opening of the main body portion. 5. The rotary shaft joint according to claim 4, wherein the rotary shaft joint is formed by injecting resin from a gate formed at a shaft center position.

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