JP2007146884A - Power transmission device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent leakage of lubricant and mixing of lubricant even if a clearance occurs due to the introduction of "shape fitting structure". <P>SOLUTION: This power transmission device is constituted in such a way that it is provided with at least a relay shaft 112 connectable with a motor shaft 102 and having a through hole 112H passing through in the axial direction and a first sun gear 118 inserted into the through hole 112H, the first sun gear 118 and the relay shaft 112 are mutually connected in an insertion part so as to transmit power while they have a clearance communicating in the axial direction, and a first sealing member 114 for blocking the through hole 112H is provided inside the through hole 112H. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a power transmission device, and more particularly to a power transmission device having a function of preventing lubricant leakage and mixing of different lubricants.

  Conventionally, various types of power transmission devices that output input power to a counterpart machine are known.

  For example, a simple planetary gear reducer that inputs the power of a power source such as a motor and decelerates and outputs the rotation of the motor via a sun gear or planetary gear, or changes the direction of the input power (if An example is a rotation direction changing device that outputs a signal while simultaneously decelerating and the like.

  As a specific example, a power transmission device 10 described in Patent Document 1 is shown in FIG. FIG. 5 is a cross-sectional view showing main components of the power transmission device 10.

  The power transmission device 10 includes a motor shaft insertion hole 19 of a motor (not shown), which is a power source, and a motor shaft (not shown) inserted into the motor shaft insertion hole 19 so as to be integrally rotated. A shaft 20, a pinion shaft 24 that can be rotated integrally with a recess 20 </ b> C provided in the joint shaft 20, a fixing bolt 28 that prevents the pinion shaft 24 from coming off, and a pinion shaft 24. The formed pinion 26 and an orthogonal gear 50 that meshes with the pinion 26 and converts the rotation of the motor shaft into an orthogonal rotation are provided. The orthogonal gear 50 is connected to the orthogonal shaft 51. The joint shaft 20 is supported by bearings 46 and 47, and is rotatable with respect to the casing 40 in which the joint shaft 20 is housed. Reference numeral 54 denotes an oil seal.

  When rotation from a motor serving as a power source is input to the power transmission device 10 via a motor shaft, this rotation is transmitted to the joint shaft 20, the pinion shaft 24, and the pinion 26, and further, the pinion 26 is engaged. The orthogonal gear 50 is rotated. The rotation of the orthogonal gear 50 is further transmitted to the orthogonal shaft 51 and is output directly or indirectly to a counterpart machine (not shown).

  The pinion shaft 24 in the power transmission device 10 includes a head portion in which a pinion 26 that meshes with the orthogonal gear 50 and a shaft portion that is fitted in the recess 20 </ b> C of the joint shaft 20.

Japanese Patent Laid-Open No. 2002-21984

  In the market, compactness is required in order to save space. Further, the larger the transmission torque capacity (load capacity) of the apparatus itself, the higher the versatility and the utility value. However, these characteristics have conflicting aspects.For example, if space saving is given priority, the strength limit of each member constituting the power transmission device, and further, the limit of the connection strength connecting the members, The transmission torque capacity tends to be small.

  For example, in the power transmission device 10 described as the conventional example, the connection strength between the joint shaft 20 and the pinion shaft 24 becomes a problem. In the power transmission device 10, the pinion shaft 24 is press-fitted and connected to the recess 20 </ b> C of the joint shaft 20. That is, the connection strength between the joint shaft 20 and the pinion shaft 24 depends on the frictional force of the press-fit portion.

  However, in the case of coupling by press-fitting, this part inevitably limits the transmission torque capacity due to the limit of the frictional force (bottleneck). On the other hand, in the case of the power transmission device 10, if the joint shaft 20 and the pinion shaft 24 are integrally formed as one member, it is not necessary to consider the connection strength of that portion, but the shape becomes very complicated and time is required for production. Costs and costs. Furthermore, it is necessary to prepare the joint part as a dedicated product according to the reduction ratio, and this also causes a high cost.

  Therefore, the present invention has been made to solve this problem, and it is an object of the present invention to provide a power transmission device having a large transmission torque capacity while avoiding costly means such as integral molding. To do.

  The present invention includes at least a joint shaft that is connectable to a driving body and has a through hole penetrating in the axial direction, and an insertion member that is inserted into the through hole. The insertion member and the joint shaft are The insertion portion is connected so as to be able to transmit power with a gap communicating in the axial direction, and a first seal member for closing the through hole is provided inside the through hole to constitute a power transmission device. This solves the above problem.

  Inventing the above solution, the inventor first introduces a “formal fitting structure” such as a spline or a D-cut into the insertion portion of the joint shaft and the pinion shaft, thereby transmitting torque. The idea of avoiding the problem of capacity and the problem of rising costs was obtained. In other words, the joint shaft and the insertion member (pinion shaft) are manufactured as separate members, thereby suppressing an increase in manufacturing cost. It is a very reasonable idea to increase the transmission torque capacity by adding the shape torque transmission resulting from "combined structure". However, when this idea was realized, new problems arose. That is, due to the introduction of the “shape fitting structure”, a gap communicating in the axial direction is generated in the insertion portion between the joint shaft and the insertion member, and the presence of this gap causes “lubricant leakage” or “ This is a problem that “mixing of lubricant” is caused.

  In the case of connection by press-fitting that has been adopted as a conventional technique, there was no problem such as a gap occurring in the connection part and leakage of the lubricant, but there is no “shape fitting structure” (for example, It is considered that fine gaps are generated by introducing spline coupling, D cut, and the like. In addition, it is difficult to completely press-fit the two members (male member and female member) for which the shape for the “shape fitting structure” is processed, and even if an accurate machining is attempted, the cost is increased. However, there is a possibility that a gap will be generated by long-term use and the lubricant will leak.

  Therefore, by providing a power transmission device with a first seal member that closes the through hole inside the through hole, the inconvenience associated with the introduction of the “form fitting structure” is eliminated, and the shape fitting is performed. An increase in transmission torque capacity accompanying the introduction of the combined structure and prevention of lubricant leakage (and mixing of lubricants) accompanying the introduction of the first seal member are realized at the same time.

  The “gap” in the present specification and claims includes those that may occur in the future as the apparatus is used.

  In the power transmission device, reliable power transmission can be performed at low cost, and lubricant leakage and lubricant mixing can be prevented.

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

  FIG. 1 is a partial cross-sectional view of a geared motor GM100 including a power transmission device 110 that is an example of an embodiment of the present invention.

  The geared motor GM100 has a structure in which a motor 100 as a drive source and a power transmission device 110 are connected and fixed by a bolt 103. The power of the motor 100 is input to the power transmission device 110 via the motor shaft (rotating drive body) 102. The motor shaft 102 is inserted into one of the through holes 112 </ b> H in the joint shaft 112 provided in the power transmission device 110 and is coupled so as to be integrally rotatable. A first sun gear (insertion member) 118 is inserted into and connected to the other of the through hole 112 </ b> H in the joint shaft 112 through a collar 116. A pinion 120 is formed by cutting the first sun gear 118 directly. In addition, what is called a "form fitting structure" is employ | adopted for the connection part of the joint shaft 112, the collar | collar 116, and the 1st sun gear 118, The detail about this point is mentioned later. The first sun gear 118 may be inserted directly into the other through hole 112H of the joint shaft 112 (without the collar 116).

  Inside the through hole 112H in the joint shaft 112, a disc-shaped rubber first seal member 114 is disposed so as to close the through hole 112H. The position where the first seal member 114 is disposed is inside the through hole 112H in the joint shaft 112, and is connected to the motor shaft (rotating drive body) in the joint shaft 112, and the first sun gear. It is desirable to be provided between the (insertion member) 118. The shape of the first seal member 114 is not necessarily limited to the disc shape as shown in FIG. Moreover, although it is not restricted to rubber, it is preferable that it is made of a material having a certain degree of elasticity.

  The joint shaft 112 is rotatably supported by the connection cover 126 via a bearing 130. An oil seal (second seal member) 128 that functions to partition the outer peripheral surface of the joint shaft 112 and the connection cover 126 is installed on the motor 100 side of the bearing 130.

  The first sun gear 118 meshes with the first planetary gear 122. The first planetary gear 122 meshes with the first sun gear 118 and simultaneously meshes with the first internal gear 124. A first carrier pin 138 passing through the first planetary gear 122 is rotatably provided at the center of the first planetary gear 122, and one end of the first carrier pin 138 is connected to the first carrier 140. The first carrier 140 is also provided with a through hole 140H penetrating in the axial direction. The second sun gear 142 is press-fitted and fixed in the through hole 140H in the first carrier 140. The teeth of the second sun gear 142 are directly cut and meshed with the second planetary gear 144. The second planetary gear 144 meshes with the second sun gear 142 and simultaneously with the second internal gear 146. In the present embodiment, the second internal gear 146 is integrally formed on the inner peripheral surface of the casing 136 of the power transmission device 110 by direct cutting. At the center of the second planetary gear 144, a second carrier pin 148 passes through the second planetary gear 144 and is rotatably provided. One end of the second carrier pin 148 is supported by the support member 153. The other end of the second carrier pin 148 is supported by the second carrier 152. The second carrier 152 and the support member 153 are connected and fixed by a connecting bolt 150. Note that the support member 153 is rotatably supported by the casing 136 via a bearing 132. The second carrier 152 is rotatably supported by the casing 136 via a bearing 134. An output shaft 154 is integrally formed with the second carrier 152, and the output shaft 154 is configured to be rotatable about the axis O1.

  The first sun is located on the left side in FIG. 1, that is, on the output shaft 154 side, with an oil seal (second seal member) 128 provided between the outer peripheral surface of the joint shaft 112 and the connection cover 126 as a boundary. A lubricant that lubricates each planetary gear, each carrier pin, and the like including the gear (insertion member) 118 is enclosed. On the other hand, the lubricant is not sealed in the present embodiment on the right side in FIG. For convenience, a region lubricated by the lubricant with the oil seal (second seal member) 128 as a boundary may be referred to as a lubrication area (second area), while a region not lubricated by the lubricant may be referred to as a non-lubrication area (first area). is there.

  Next, a connecting portion between the joint shaft 112, the collar 116, and the first sun gear 118 will be described in detail with reference to FIG. FIG. 2 is an enlarged view showing only the joint shaft 112, the collar 116, the first sun gear 118, and the first seal member 114 in FIG. In addition, a cross-sectional view taken along line XX in the enlarged view is shown on the left side of FIG.

  A first sun gear 118 is connected to the joint shaft 112 via a collar 116. This connection state will be described in more detail. The joint shaft 112 and the collar 116 are fixed by press-fitting. In other words, the joint shaft 112 and the collar 116 are fixed so as to be integrally rotatable by a frictional force. On the other hand, the collar 116 and the first sun gear 118 are provided on the female spline 116S provided on the inner peripheral surface of the collar 116 and the outer peripheral surface of the first sun gear 118 (the outer peripheral surface of the portion inserted into the joint shaft). A shape fitting structure is formed by the male spline 118S. That is, the collar 116 and the first sun gear 118 are connected so as to be integrally rotatable by geometric fitting. In addition, “shape fitting” means a structure in which a male member and a female member are fitted in cross-sectional shapes corresponding to each other other than a perfect circle, and includes a key connection and the like. is there. In the present embodiment, a shape fitting portion 117 is provided in which a shape fitting structure by the male spline 118S and the female spline 116S is provided over the entire portion of the first sun gear 118 inserted into the collar 116. However, only a part may be used. In addition, you may provide the female spline 116S corresponding to the male spline 118S provided in the 1st sun gear 118 directly in the through-hole 112H in the joint shaft 112, without passing through the collar 116 demonstrated in this embodiment.

  Also, introducing the above-described “shape fitting structure” into the insertion portion of the first sun gear 118 means that there is a high possibility that a “gap communicating in the axial direction” will be formed at this portion at the same time. To do. In other words, even if the shape of the fitting structure portion (in this embodiment, the female spline 116S and the male spline 118S in this embodiment) is processed with high accuracy, a fine gap is formed so that the lubricant can pass ( Even if it does not occur at the beginning of assembly, it is likely to be caused by operation).

  In addition, although the through hole 112H in the present embodiment has a step K therein, the step K is not an essential component. That is, a through hole without a step from one end to the other end of the through hole 112H may be formed.

  Further, the diameter of the first seal member 114 disposed inside the through hole 112H is designed to be slightly larger than the diameter D of the through hole 112H, and the first seal member 114 is attached to the through hole 112H. At this time, the first seal member 114 is mounted in a slightly compressed state. That is, the sealing performance (blocking performance) for the through hole 112H is improved by the elastic restoring force of the first seal member 114 itself.

  Then, the effect | action of the power transmission device 110 is demonstrated. When power from the motor 100 is input to the joint shaft 112 via the motor shaft 102, the rotational force is transmitted to the first sun gear 118 via the collar 116. The rotation of the first sun gear 118 is transmitted to the first planetary gear 122. Since the first planetary gear 122 meshes with the first sun gear 118 and simultaneously with the first internal gear 124, the rotation of the first sun gear 118 rotates as the first sun gear 118 rotates. Revolving slowly in the same direction as the rotation direction of the first sun gear 118 while rotating in the direction opposite to the direction. This slow (decelerated) revolution is transmitted to the first carrier 140 via the first carrier pin 138 passing through the first planetary gear 122. That is, as the first planetary gear 122 revolves, the first carrier 140 also rotates. The rotation of the first carrier 140 is further transmitted to the second sun gear 142 that is integrally connected by press-fitting. The rotation of the second sun gear 142 is transmitted to the meshing second planetary gear 144. Since the second planetary gear 144 is meshed with the second sun gear 142 and simultaneously with the second internal gear 146, the rotation of the second planetary gear 144 is opposite to the rotation of the second sun gear 142. While rotating in the direction, it revolves more slowly (decelerated) in the same direction as the rotation direction of the second sun gear 142. This revolution component is transmitted to the support member 153 and the second carrier 152 via the second carrier pin 148 penetrating the second planetary gear 144. Since the output shaft 154 is integrally formed with the second carrier 152, the slow rotation of the second carrier 152 is output as the rotation of the output shaft 154 and transmitted to the other machine (not shown). Become. In the power transmission device 110 described above, a two-stage reduction mechanism that reduces the rotation of the motor 100 as a power source in two stages is provided. However, the present invention is limited to this two-stage reduction mechanism. It may be a one-stage speed reduction instead of a thing, and there is no problem even if it is three or more stages.

  Further, as described above, a lubricant is sealed on the output shaft 154 side (second area) with the oil seal (second seal member) 128 positioned between the joint shaft 112 and the connection cover 126 as a boundary. Yes. However, in this embodiment, since the oil seal 128 described above is provided on the outer peripheral surface side of the joint shaft 112, this lubricant leaks from the outer peripheral surface side of the joint shaft to the non-lubrication area (first area). That is prevented. The joint shaft 112 has a through hole 112H. One end of the through hole 112H is located in the non-lubricated area (first area), and the other end is a lubricated area (second Therefore, the lubricant may leak into the non-lubricated area through the through hole 112H. However, in the present embodiment, since the first seal member 114 is arranged in the through hole 112H, the case where the power transmission device 110 is operated and the lubricant is stirred, Even when the viscosity of the lubricant is lowered (the fluidity is improved) due to the temperature rise, the lubricant is prevented from leaking to the non-lubricated area side.

  In the present embodiment, the first sun gear 118 is connected to the through hole 112 </ b> H in the joint shaft 112 via the collar 116. Thereby, even if the diameter of the shaft of the first sun gear 118 which is an insertion member is thin, it can be adjusted to the size of the through hole 112H of the joint shaft 112. Further, a large surface area of the press-fitted portion (press-fitted portion between the through hole 112H and the collar 116) can be secured, and the transmission torque capacity is also increased. Furthermore, the frictional force with the joint shaft 112 can be improved by appropriately adjusting the material of the members constituting the collar 116.

  Subsequently, an example of another embodiment of the present invention will be described. FIG. 3 is a diagram illustrating an example of another embodiment of the present invention, and corresponds to FIG. 2 in the power transmission device 110 described above.

  In the joint shaft 112 in the power transmission device 110, the through hole 112H itself functions as an insertion hole (motor shaft insertion hole) of the motor shaft 102 as a “rotating drive body”. On the other hand, in this embodiment, the through hole 212H in the joint shaft 212 does not function as a driving body insertion hole into which the “rotating driving body” is inserted. Instead, a rotational force is transmitted to the joint shaft 212 via the roller 280 on the outer peripheral surface of the joint shaft 212. Further, a rubber-made bottomed cylindrical body (first seal member) 214 having a “U-shaped” cross section is disposed inside the through-hole 212 </ b> H in the joint shaft 212. Also, the oil seal 228 (second seal member) provided between the outer peripheral surface of the joint shaft 212 and the connection cover 226 is used as a boundary, and the roller 280 is lubricated on the right side in FIG. A first lubricant is enclosed. On the other hand, with the oil seal 228 as a boundary, the first sun gear (insertion member) 218, each planetary gear, each carrier pin, and the like are lubricated on the left side in FIG. 3, that is, on the first sun gear 218 side. A second lubricant is enclosed. For convenience, a region lubricated by the first lubricant with the oil seal (second seal member) 228 as a boundary is referred to as a first area, and a region lubricated by the second lubricant is referred to as a second area.

  In the present embodiment, the first lubricant is imparted with a property for appropriately securing the traction (power transmission force) between the roller 280 and the joint shaft 212 while protecting the roller 280. On the other hand, the second lubricant has a property of reducing friction between the members as much as possible while reducing the meshing sound. It is not preferable that the lubricants having such different properties are mixed with each other, causing a decrease in the performance of each other.

  However, in this embodiment, since the oil seal 228 described above is provided on the outer peripheral surface side of the joint shaft 212, each lubricant is mixed by leaking from the outer peripheral surface side of the joint shaft 212 to other areas. That is prevented. Further, the joint shaft 212 has a through hole 212H, one end of the through hole 212H is located in the first area where the first lubricant is arranged, and the other end is arranged with the second lubricant. Since the lubricant is located in the second area, the lubricant may be mixed by leaking out to other areas through the through hole 212H. However, since the bottomed cylindrical body (first seal member) 214 is arranged inside the through hole 212H, the case where each lubricant is stirred by the operation of the power transmission device, or the temperature inside the device Even when the viscosity of the lubricant is lowered (the fluidity is improved) due to the rise, the lubricant is prevented from being mixed.

  The bottomed cylindrical body 214 having a U-shaped cross section may include, for example, a metal core material therein.

  Next, an example of another embodiment according to the present invention will be described with reference to FIG. Here, the joint shaft 312 and the first seal member 314, the collar 316, the first sun gear 318, and the motor shaft 212 will be taken out and described.

  The basic configuration is the same as that in the power transmission device 110 described with reference to FIGS. 1 and 2. However, as a feature of this embodiment, the first seal member 314 provided inside the through hole 312H in the joint shaft 312 is a motor shaft 302 that is two members inserted into the through hole 312H, and the first sun gear 318. Both are subjected to axial pressure PR. Since the first seal member 314 is formed of an elastic body having elasticity, the reaction force is applied in the radial direction of the joint shaft 312 when pressure is applied by another member from both sides in the axial direction. The That is, the contact surface pressure with the through-hole 312H in the first seal member 314 becomes larger than when no pressure is received from the motor shaft 302 and the first sun gear 318 from the axial direction. This means that the sealing performance (blocking performance) of the through hole 312H in the first sealing member 314 is improved. By setting it as such a structure, the sealing performance in a through-hole can be improved further.

  In this case, the shape of the first seal member 314 may not be a disc shape as shown in FIG. 4, and may be, for example, a spherical shape. When such a spherical first seal member is used, the insertion operation into the through hole becomes easy.

  In the embodiments described so far, the present invention is mainly described as an embodiment in which the present invention is applied to the input shaft portion in the power transmission device, but the application portion of the present invention is limited to this portion. is not. For example, in the case of the power transmission device 110 shown in FIG. 1, the first carrier 140 can function as a “joint shaft having a through hole”.

  In the above-described embodiments, all are described as a simple planetary gear mechanism having a sun gear and a planetary gear, but the application of the present invention is not limited to the power transmission device of this simple planetary gear mechanism. For example, instead of the sun gear, an inward swing meshing type power transmission device in which an “eccentric body shaft” having an eccentric body as an insertion member is inserted may be used.

  Furthermore, in the above-described embodiments, all “reduction gears” as power transmission devices are described. However, the present invention is not limited to this reduction device. For example, it may be a speed increaser or power that changes the direction of power. It may be a conversion device.

  The present invention can be widely applied to a power transmission device that outputs input power to a counterpart machine.

Sectional drawing of the geared motor provided with the power transmission device which is an example of embodiment of this invention 1 is an enlarged view near the joint shaft in FIG. 1 and a cross-sectional view taken along line XX in this enlarged view. Sectional drawing which shows other embodiment of this invention. Sectional drawing which shows another embodiment of this invention. Sectional drawing of the power transmission device described in patent document 1

Explanation of symbols

GM100 ... Geared motor 100 ... Motor 101 ... Motor casing 102 ... Motor shaft 103 ... Bolt 110 ... Power transmission device 112 ... Joint shaft 112H ... Through hole 114 ... First seal member 116 ... Collar 116S ... Female spline 117 ... Shape fitting part 118 ... first sun gear 118S ... male spline 120 ... pinion 122 ... first planetary gear 124 ... first internal gear 126 ... connection cover 128 ... oil seal (second seal member)
130, 132, 134 ... bearing 136 ... casing 138 ... first carrier pin 140 ... first carrier 142 ... second sun gear 144 ... second planetary gear 146 ... second internal gear 148 ... second carrier pin 150 ... connecting bolt 152 ... 2nd carrier 154 ... Output shaft

Claims (6)

A connecting shaft that is connectable to the driving body and has a through hole penetrating in the axial direction;
And at least an insertion member inserted into the through hole,
In the insertion portion, the insertion member and the joint shaft are connected so as to be able to transmit power in a state having a gap communicating in the axial direction,
The power transmission device according to claim 1, wherein a first seal member that closes the through hole is provided inside the through hole. In claim 1,
The said clearance gap is formed of the shape fitting structure. The power transmission device characterized by the above-mentioned. In claim 1 or 2,
The power transmission device, wherein the joint shaft and the insertion member are connected via a collar so as to be able to transmit power. In any one of Claims 1 thru | or 3,
The casing of the power transmission device includes at least a first area that can enclose a first lubricant that lubricates the driving body and a second area that can enclose a second lubricant that lubricates the insertion member. And
One shaft end of the joint shaft is located in the first area, the other shaft end is located in the second area, and
Between the outer peripheral surface of the said joint shaft and the said casing, the 2nd seal member which partitions off the said 1st area and the 2nd area is provided. The power transmission device characterized by the above-mentioned. 5. The method according to claim 1, further comprising:
The power transmission device, wherein the through hole functions as a driving body insertion hole. In claim 5,
An axial pressure is applied to the first seal member from the driving body and the insertion member, respectively.

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