JP2010091023A - Speed reducer, and structure mounting speed reducer on counter machine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simplify the fitting of a speed reducer to a driven shaft of a counter machine or the maintenance thereof in operation while effectively prevent fretting. <P>SOLUTION: A geared motor (speed reducer) GM 1 which drives the driven shaft 28 of the counter machine includes an output shaft 24 including a through-hole 24h to which the driven shaft 28 is inserted, and capable of transmitting its own rotation to the driven shaft 28 by a key (shape engagement) 32. A space part SP1 capable of retaining grease G1 is secured between an inner circumference 24A of the output shaft 24 and an outer circumference 28A of the driven shaft 28 along the output shaft 24 from an end portion 24B of the output shaft 24. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a reduction gear and a structure for mounting the reduction gear to a counterpart machine.

  Patent Document 1 discloses a structure in which a hollow output shaft of a reduction gear is directly fitted into a driven shaft of a counterpart machine. In this document, a method using frictional fastening without a gap and a method using geometric engagement with a key are proposed for connecting the driven shaft and the output shaft.

JP 2001-99177 A

  However, in the method of connecting the driven shaft and the output shaft by frictional fastening, it is necessary to always properly manage the tightening torque not only when the speed reducer is attached but also after the attachment. For this reason, there is a problem that it is troublesome to attach the reduction gear to the counterpart machine and to maintain it.

  On the other hand, the method of connecting the driven shaft and the output shaft by utilizing the geometrical engagement by the key has a minute gap due to a dimensional difference between the shaft and the minute gap of the geometrical engagement portion. Since it remains, there is a problem that fretting tends to occur inevitably. Since it is necessary to fit the shaft center of the driven shaft and the output shaft while holding the heavy speed reducer, the speed reducer needs to be fitted into the driven shaft, so that the inner diameter of the output shaft and the outer diameter of the driven shaft are This is because it is necessary to ensure a corresponding “dimension difference”. Ensuring ease of insertion and preventing fretting are in a trade-off relationship. If priority is given to ease of insertion and the dimensional difference is set larger, fretting is more likely to occur. If the dimensional difference is set to be small, fretting is less likely to occur, but the insertion work becomes extremely difficult.

  The present invention has been made to solve such a conventional problem, and effectively prevents the occurrence of fretting, and at the same time, inserts and operates the speed reducer on the driven shaft of the counterpart machine. The task is to simplify the maintenance at the time.

  The present invention provides a reduction gear for driving a driven shaft of a counterpart machine, wherein a driven output shaft of the counterpart machine is inserted, and a hollow output shaft is coupled to the driven shaft so as to transmit power with a gap. The above problem is solved by securing a space capable of holding grease between the inner periphery of the output shaft and the outer periphery of the driven shaft from the end of the output shaft along the output shaft. It is a thing.

  In the present invention, since a space capable of holding the grease is secured between the inner periphery of the hollow output shaft and the outer periphery of the counterpart machine, air cannot enter the inside in the axial direction from the space. For this reason, even if the driven shaft and the output shaft are coupled to each other so as to be able to transmit power with a gap, fretting can be reliably prevented over a long period of time.

  Further, since this space portion is formed in the vicinity of the end portion of the output shaft, the presence of the space portion causes a difference between the outer peripheral diameter of the counterpart machine at the end portion of the output shaft and the inner peripheral diameter at the end surface of the output shaft. Is getting bigger. Therefore, it is very easy to attach the reduction gear to the counterpart machine. Therefore, it is possible to reduce the dimensional difference on the inner side in the axial direction from the space without any hindrance, and it is more difficult for fretting to occur, and there is no risk of rattling or shaking.

  In the present invention, what has been subjected to a so-called “chamfering” process is not included in the concept of the “space part” of the present invention for the purpose of the invention. Usually, the radius R when chamfering is less than 5% of the inner diameter (diameter) of the shaft. For example, when the inner diameter (diameter) of the hollow portion of the output shaft is 15 mm to 55 mm, the chamfer radius is about 0.5 mm to 2.5 mm, and does not reach 5% even if it is large. Therefore, the chamfering in this range is technically different from the “space part” of the present invention.

  According to the present invention, it is possible to effectively prevent the occurrence of fretting, and to simplify the fitting and maintenance of the reduction gear to the driven shaft of the counterpart machine.

  Hereinafter, an example of an embodiment of the present invention will be described in detail with reference to the drawings.

  FIG. 1 is a partial schematic cross-sectional view showing a geared motor (decelerator) to which an example of an embodiment of the present invention is applied, and FIG. 2 is an enlarged cross-sectional view of an arrow II portion thereof.

  The geared motor GM1 is mainly composed of a motor 16 and a speed reducer 18. The motor 16 includes a motor casing 20, and the speed reducer 18 includes a speed reducer casing 22. A hollow output shaft 24 is rotatably supported on the reduction gear casing 22.

  The output shaft 24 includes a through hole 24h into which a driven shaft 28 such as a conveyor (mating machine: not shown) is inserted. Power transmission between the output shaft 24 and the driven shaft 28 is performed by a “shape engagement” via the key 32, that is, a structure that is coupled so as to transmit power with a gap. Instead of the shape engagement by the key 32, for example, shape engagement such as a spline may be used. In the present invention, the specific configuration of the motor 16 of the geared motor GM1 or the configuration of the speed reduction mechanism of the speed reducer 18 is not particularly limited.

  As shown in detail in FIG. 2, a space SP1 capable of holding the grease G1 is secured between the inner periphery 24A of the output shaft 24 and the outer periphery 28A of the driven shaft 28 of the counterpart machine. In this embodiment, the length Ls1 in the axial direction X of the space portion SP1 is set to about ½ of the radius Hr1 (other than the space portion PS1) of the through hole 24h of the output shaft 24. For example, if the shaft has an inner diameter (Hrle × 2) of 15 mm, it is about 3 to 5 mm, and if the shaft has an inner diameter (Hrle × 2) of 55 mm, it is about 5 to 10 mm. This is because even if the grease G1 has been somewhat dried, it has been considered that fretting is prevented while reliably preventing air from entering the space portion SP1 in the axial direction. It is clearly larger than the radius 0.5 mm to 2.5 mm with respect to the shaft having the same inner diameter of R.

  The space portion SP1 has a shape in which the height SPh1 in the radial direction R of the space portion SP1 increases toward the end portion 24B of the output shaft 24 along the axial direction X of the output shaft 24. As a result, the radius Hr1e of the through hole 24h of the output shaft 24 at the end surface 24C portion of the output shaft 24 is only Δ1 from the radius Hr1 at a portion other than the space portion SP1 of the through hole 24h (2 of Δ1 in terms of diameter). Double) big. For example, when the inner diameter (Hrle × 2) is 15 mm to 55 mm, Δ1 is about 1.5 mm to 5.5 mm (about 10% of the inner diameter). This is also clearly larger than the chamfer radius R of 0.5 mm to 2.5 mm (about 5% of the inner diameter). As a result, the gap between the output shaft 24 in the vicinity of the central portion in the axial direction and the driven shaft 28 of the counterpart machine is maintained at a minute gap of about 0.6 mm (i.e., less likely to cause fretting). In particular, it is possible to obtain a large amount of grease G1 in the vicinity of the end of the output shaft 24 and to make it very easy to fit the output shaft 24 into the driven shaft 28. This effect is particularly beneficial when used in a factory where the geared motor GM1 must be frequently disassembled and cleaned, such as a food factory.

  In this example, the driven shaft 28 of the counterpart machine has a step surface 28 </ b> B that regulates the insertion end of the output shaft 24. The step surface 28B is perpendicular to the driven shaft 28, and can contact the end surface 24C of the output shaft 24 to close the space SP1 (also serves as a closing means).

  Next, the operation of the geared motor GM1 will be described.

  The geared motor GM1 is assembled (inserted) into the driven shaft 28 of the counterpart machine by aligning the axis O1 of the output shaft 24 with the axis O2 of the driven shaft 28 of the conveyor 26 and holding the geared motor GM1 in hand. This is done by fitting the through hole 24 h of the output shaft 24 together with the key 32 into the driven shaft 28.

  Before fitting, grease (G1) is applied to the outer periphery 28A of the driven shaft 28 or (and) the inner periphery 24A of the output shaft 24. In this state, the geared motor GM1 is applied to the driven shaft 28 of the counterpart machine. The grease (G1) is pushed out and satisfactorily filled in the space SP1. The output shaft 24 is inserted until it contacts the step surface 28B of the driven shaft 28.

  Since the space portion SP1 is formed in the vicinity of the end surface 24C of the output shaft 24, the presence of the space portion SP1 results in the radius of the through hole 24h of the output shaft 24 at the end surface 24C portion of the output shaft 24. Hr1e is larger by Δ1 than the radius Hr1 at a portion other than the space portion SP1 of the through hole 24h, so that the reduction gear can be fitted and attached to the counterpart machine very easily.

  The excess grease (G1) overflowing from the step surface 28B and the end surface 24C of the output shaft 24 with the insertion is wiped off, and the grease G1 is filled and held in the space SP1 without any gap.

  The space SP1 in which the grease G1 is held is blocked by the step surface 28B of the driven shaft 28, and air is prevented from entering. For this reason, quality deterioration (especially drying) and chemical change over time of the grease G1 in the space SP1 are effectively suppressed. As a result, due to the presence of the space portion SP1 in which the grease G1 is held, the fretting around the inner and outer circumferences 24A and 28A of the output shaft 24 and the driven shaft 28 and the key 32 where the shape engagement is made is prolonged. Reliably prevented.

  As a result, it has been possible to achieve both “ensuring ease of insertion” and “preventing fretting”, both of which are conventionally traded off.

  Next, the example of the variation regarding formation of a space part is demonstrated.

  In the present invention, the specific shape of the space is not particularly limited. As the shape of the space portion, for example, a variation as shown in FIG. 3 can be considered.

  In the example of filling the grease G2 in the space portion SP2 in FIG. 3A, the radial height 52h at the specific portion A substantially in the center in the axial direction of the space portion SP2 is the radius at both sides in the axial direction. It is larger than the height 52i, 52j in the direction. That is, as a result, the grease reservoir 52 is formed in the specific portion A of the space SP2 in the through hole 62h of the output shaft 62. The presence of the grease reservoir 52 makes it possible to secure a larger absolute amount of the grease G2 even if the axial length Ls2 of the space SP2 is the same as the axial length Ls1 of the space SP1 of the previous example. The quality deterioration of the grease G2 can be further suppressed.

  The shape of the grease reservoir 52 is not limited to this shape. Further, the formation position of the grease reservoir 52 in the axial direction (the axial position of the specific portion A) is not limited to the position shown in FIG. Similar effects can be obtained even if the grease reservoir 52 is formed at the innermost position in the axial direction of the space portion SP2. The space shape as a base is not limited to the example of FIG. 3, and for example, a grease reservoir can be formed also in FIG. In addition, the code | symbol is attached | subjected also about the code | symbol about the part of the part which is the same or functionally the same as previous embodiment. The same applies to the following embodiments.

  In the example of the grease G4 in the space SP4 in FIG. 3B, since the opening of the through hole 64h of the output shaft 64 is large, the insertion of the output shaft 64 is easy, and the axial length Ls4 of the space SP4 is further increased. Since it is long, it is possible to prevent deterioration of the quality of the portion located in the innermost part of the grease G4 as much as possible, and an effective suppressing action is also obtained with respect to fretting.

  In the present invention, it is not always necessary to close the space, but it is preferable to close the space because there is little deterioration in the quality of the grease. In the above-described example, the driven shaft 28 uses the step surface 28 as the closing means. However, when the driven shaft does not have the step surface, for example, as shown in FIG. In addition, a V-ring (elastic ring: the cross-sectional shape does not necessarily have to be V-shaped) 70 for closing the space SP1 may be attached. The V ring 70 is in contact with the outer peripheral surface 29A of the driven shaft 29 and the end surface 24C of the output shaft 24 of the counterpart machine. In addition, it is preferable to fill the grease G11 also in the minute space SP11 surrounded by the V ring 70, the end surface 24C of the output shaft 24, and the outer periphery 29A of the driven shaft 29. As a result, the space filled with the greases G1 and G11 becomes SP1 + SP11.

  By arranging the V rings 70 and 72 in this way, the space portions SP1 and SP3 can be closed and shielded from the air even if the driven shaft 29 has no step surface. As a result, quality degradation of the greases G1, G11, G3, and G13 can be suppressed, and the fretting prevention effect can be maintained for a longer period.

  Note that the example of FIG. 4B is basically the same as the previous embodiment of FIG. 2, and the step surface 28B closes the space portion SP1. Therefore, it can be said that the V-ring is not necessary, but the V-ring 74 is disposed in contact with the base outer peripheral surface 28D of the driven shaft 28 and the end surface 24C of the output shaft 24 for further blockage. . Further, the minute space SP21 formed by the presence of the V ring 74 is also filled with the grease G21.

  As a result, the grease G1 filled in the space SP1 is almost completely sealed, and the deterioration of the quality can be kept to a minimum over a long period. Therefore, the fretting prevention effect is extremely high.

  As described above, various variations can be considered in the present invention, but the embodiment shown in FIG. 2 is most preferable overall. This is because a large amount of grease G1 can be secured in a sealed state between the output shaft and the driven shaft, particularly in the vicinity of the end of the output shaft, and the space portion is converged “without a step”. This is because the insertion of the output shaft can be performed very easily and smoothly. In this sense, it can be said that the embodiment of FIG. 2 most effectively achieves both prevention of fretting and ease of insertion.

  Like a conveyor speed reducer, it can be used as a speed reducer that is directly attached to a driven shaft of a counterpart machine.

Plan sectional drawing which shows a part of geared motor (reduction gear) to which an example of the embodiment of the present invention was applied 1 is an enlarged cross-sectional view of the II portion indicated by an arrow in FIG. 1 showing a space for holding the geared motor grease. Sectional drawing equivalent to FIG. 2 which shows the other example of a space part Sectional drawing equivalent to FIG. 2 which shows the example which attached V ring

Explanation of symbols

GM1 ... Geared motor 16 ... Motor 18 ... Reduction gear 20 ... Motor casing 22 ... Reduction gear casing 24 ... Output shaft 24h ... Through hole 24A ... Inner circumference 24B ... End 24C ... End face 28 ... Driven shaft 28A ... Outer circumference 28B ... Stepped surface 32 ... Key

Claims (6)

In the speed reducer that drives the driven shaft of the counterpart machine,
A driven output shaft of the counterpart machine is inserted, and a hollow output shaft is coupled to the driven shaft so as to transmit power with a gap.
A speed reduction device characterized in that a space capable of holding grease is secured between the inner periphery of the output shaft and the outer periphery of the driven shaft from the end of the output shaft along the output shaft. In claim 1,
The reduction gear according to claim 1, wherein a height of the space portion in a radial direction increases toward an end portion of the output shaft along an axial direction of the output shaft. In claim 1 or 2,
The reduction gear according to claim 1, wherein a height in a radial direction at a specific portion in the axial direction of the space portion is larger than a height in a radial direction at both axial sides of the specific portion.   A structure for mounting the reduction gear according to any one of claims 1 to 3 to a counterpart machine, wherein the reduction gear includes a closing means for closing the space portion. Construction. In claim 4,
The driven shaft of the counterpart machine has a stepped surface that restricts the insertion end of the output shaft;
A structure for mounting a reduction gear to a counterpart machine, wherein the stepped surface also serves as the closing means. In claim 4,
A structure for mounting a reduction gear to a counterpart machine, wherein the closing means is an elastic ring that contacts an outer periphery of the driven shaft and an end surface of the output shaft of the counterpart machine.

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