Patent Publication Number: US-2012036958-A1

Title: Speed reducing device

Description:
RELATED APPLICATION 
     Priorities are claimed to Japanese Patent Application No. 2010-180499, filed Aug. 11, 2010, and Japanese Patent Application No. 2011-136401, filed Jun. 20, 2011, the overall contents of each of which are incorporated herein by reference. 
     BACKGROUND 
     1. Technical Field 
     The present invention relates to a speed reducing device, and particularly, to a speed reducing device to which a thrust load is applied from a shaft of a counterpart machine. 
     2. Description of the Related Art 
     Japanese Utility Model Application Publication No. 61-040343 discloses a stirring device of which a stirring shaft is connected to a geared motor (a motor attachment speed reducing device). 
     As shown in  FIG. 6 , in a stirring device  2  disclosed in Japanese Utility Model Application Publication No. 61-040343, a connection mechanism  10 , which may receive a thrust load, is disposed between an output shaft  6  of a speed reducing motor (a geared motor)  4  and a stirring shaft (a shaft of a counterpart machine)  8 . 
     The connection mechanism  10  is configured to be connected to the stirring shaft  8 , an intermediate shaft  20 , a joint  18 , and the output shaft  6  of the speed reducing motor  4  (as four casing members) inside a tank  16  of the stirring device  2 , a bearing housing  14 , a motor base  12 , and a casing  4 A of the speed reducing motor  4  (as four casing members). 
     The stirring shaft  8  is inserted into a concave portion  20 A of the intermediate shaft  20 , and is connected to the intermediate shaft  20  through a fastening bolt  22  and a fastening pin  24 . The thrust load transmitted from the stirring shaft  8  is received by the bearing housing  14  of the connection mechanism  10  through a pair of bearings  26  and  28  supporting the intermediate shaft  20 . 
     SUMMARY 
     According to an embodiment of the invention, there is provided a speed reducing device of which one end side of an output shaft is received in a casing of the speed reducing device and the other end side of the output shaft is connected to a shaft of a counterpart machine to which a thrust load is applied, the speed reducing device including: a bearing that directly supports the output shaft to be rotatable and receives a thrust load applied to the output shaft; a hollow body that includes a hollow portion and rotates along with the output shaft; and a connection member that is inserted into the hollow portion of the hollow body to be connected to the hollow body and the shaft of the counterpart machine, wherein the bearing receives the thrust load applied from the shaft of the counterpart machine to the output shaft through the connection member. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a cross-sectional view illustrating a main configuration of a speed reducing device which is an example of one embodiment of the invention. 
         FIG. 2  is a partially enlarged cross-sectional view illustrating a configuration near a connection shaft of  FIG. 1 . 
         FIG. 3  is a cross-sectional view taken along the line indicated by the arrow of  FIG. 2 . 
         FIG. 4  is an overall cross-sectional view illustrating a stirring device adopting the speed reducing device according to an example of the embodiment of the invention. 
         FIG. 5  is a cross-sectional view illustrating a configuration of the speed reducing device according to an example of another embodiment of the invention. 
         FIG. 6  is a cross-sectional view illustrating an example of an existing speed reducing device. 
     
    
    
     DETAILED DESCRIPTION 
     In general, in a speed reducing device of which an output shaft is largely offset from an input shaft to a degree more than the radial dimension of a motor, the offset output shaft is made to penetrate an opposite counterpart machine side of the casing of the speed reducing device, the output shaft is formed to be hollow, the shaft of the counterpart machine is inserted into the hollow output shaft, and the shaft is coupled to the output shaft in the axial direction, so that a connection mechanism receiving a thrust load may be comparatively easily configured. 
     However, in the case of the speed reducing device of which one end side of the output shaft is receive in the casing of the speed reducing device, it is very difficult to connect the output shaft and the shaft of the counterpart machine to each other to receive a thrust load. For this reason, consequently, the connection mechanism connecting the speed reducing device and the shaft of the counterpart machine to each other has problems in that the number of components is large and the structure is complex as in the example of Japanese Utility Model Application Publication No. 61-040343. 
     There is a need for providing a speed reducing device of which one end side of an output shaft is received in a casing of the speed reducing device and the other end side of the output shaft is connected to a shaft of a counterpart machine to which a thrust load is applied, the speed reducing device receiving the thrust load from the shaft of the counterpart machine with a small number of components and a simple configuration. 
     In the embodiment of the invention, it is found that the above-described problem is largely involved with the basic configuration in which the connection mechanism capable of receiving the thrust load is disposed between the speed reducing device and the shaft of the counterpart machine, and the above-described problem is solved by drastically re-examining the basic configuration. 
     That is, the existing connection mechanism needs to have not only a function of transmitting the rotation (torque) of the output shaft of the speed reducing device to the shaft of the counterpart machine, but also a function of receiving the thrust load from the shaft of the counterpart machine (a function of not transmitting the thrust load to the speed reducing device). It is considered that the structure of the connection mechanism becomes complex due to the demand in which the “connection mechanism with two functions is disposed between the speed reducing device and the counterpart machine”. 
     From this view point, in the embodiment of the invention, (at least one) bearing directly supporting the output shaft (to be described later in detail) is set to a bearing capable of receiving the thrust load, and the connection member is made to be inserted into the hollow portion of the hollow body rotating along with the output shaft. The connection member is configured to be connected to the hollow body and the shaft of the counterpart machine. 
     With this configuration, in the embodiment of the invention, since the high rigidity of the casing of the speed reducing device may be reasonably used, there is a no need to dispose a connection mechanism receiving a thrust load between the speed reducing device and the shaft of the counterpart machine. For this reason, the overall configuration may be remarkably simplified. 
     According to the embodiment of the invention, a speed reducing device may be simply obtained which receives a thrust load from a shaft of a counterpart machine with a small number of components by adopting a configuration in which one end side of an output shaft is received in a casing of the speed reducing device. 
     Hereinafter, an example of an embodiment of the invention will be described in detail with reference to the drawings. 
       FIG. 4  is an overall cross-sectional view illustrating a stirring device adopting a speed reducing device according to an example of the embodiment of the invention, and  FIG. 1  is a cross-sectional view illustrating a main configuration of the speed reducing device. 
     As shown in  FIGS. 4 and 1 , a speed reducing device  30  is an inline-type speed reducing device of which an input shaft  32  and an output shaft  34  are coaxially disposed. In the speed reducing device  30 , one end side (in this example, the upside) of the output shaft  34  is received in a casing  84  of the speed reducing device  30 . The speed reducing device  30  is installed and fixed to an upper portion of a tank  38  of a stirring device  36 , and the other end side of the output shaft  34  is connected to a stirring shaft  40  (the shaft of the counterpart machine) of the stirring device  36 . 
     Since the stirring shaft  40  and a stirring blade  42  have corresponding own weight, a thrust load is normally applied to the stirring shaft  40  downward (toward the arrow A) in the perpendicular direction. Further, when a stirring operation is started, since a reaction force is applied from a liquid in the tank  38  to the stirring blade  42 , a thrust load may be applied to the stirring shaft  40  upward (toward the arrow B) in the perpendicular direction. 
     In the embodiment, the thrust load is received by ball bearings  44  and  46  each having a function of a thrust bearing directly supporting the output shaft  34  of the speed reducing device  30 . Hereinafter, a configuration of a speed reducing mechanism of the speed reducing device  30  will be sequentially described. 
     The speed reducing device  30  includes an oscillational internal meshing planetary gear speed reducing mechanism  48 . 
     A motor shaft  52  of a motor  50  also serves as an input shaft  32  of the speed reducing device  30 . Eccentric bodies  54  and  56  are fixed to the input shaft  32  through a key  58 . External tooth gears  60  and  62  are assembled to the outer peripheries of the eccentric bodies  54  and  56 . The external tooth gears  60  and  62  internally mesh with the internal tooth gear  64 . The internal tooth gear  64  is integrated with the casing  84  of the speed reducing device  30 . 
     Inner pin holes  60 A and  62 A are formed in the external tooth gears  60  and  62 , and an inner pin  68  fixed to a flange member  66  loosely penetrates the inner pin holes  60 A and  62 A. The number of teeth of the external tooth gears  60  and  62  is smaller than that of the internal tooth gear  64  by one. 
     For this reason, when the input shaft  32  (as the motor shaft  52  of the motor  50 ) of the speed reducing device  30  rotates, the eccentric bodies  54  and  56  rotate, and the external tooth gears  60  and  62  oscillate and internally mesh with the internal tooth gear  64 . As a result, whenever the input shaft  32  rotates once so that the external tooth gears  60  and  62  oscillate once, the external tooth gears  60  and  62  are deviated (rotated) by one tooth with respect to (the fixed) internal tooth gear  64 . The rotation component is transmitted to the flange member  66  through the inner pin  68 , so that a speed is reduced at a speed reduction ratio of 1/(the number of teeth of the external tooth gear), and a rotation is extracted from a load-side shaft member  70  connected to the flange member  66  while the speed is reduced. 
     Here, in the invention, the “output shaft” of the speed reducing device is defined as a “member or a group of members of an independently rotatable minimal structure as a member or a group of members constituting a final speed reducing stage”. This definition is derived from the point in which the “invention receives the thrust load of the shaft of the counterpart machine through the bearing directly supporting the output shaft as a component of the speed reducing device”. That is, the output shaft according to the embodiment of the invention maybe formed as a single component (a single member) or a plurality of members connected and fixed to each other through a bolt and the like. 
     As a group of members constituting the final speed reducing stage of the embodiment, there are the flange member  66 , the load-side shaft member  70 , and a connection member  72  to be described later. However, here, the “flange member  66  and the load-side shaft member  70 ” correspond to the “output shaft” according to the embodiment of the invention. This is for the following reason. In the embodiment, since the flange member  66  is supported in the casing  84  only through one ball bearing  44 , it is difficult to mention that only the flange member  66  independently rotates and serves as the “output shaft” extracting the output torque of the final speed reducing stage to the shaft of the counterpart machine. On the contrary, when a “group of members” is considered which includes the “flange member  66  and the load-side shaft member  70 ”, the group of members are supported (independently rotate) in the casing  84  of the speed reducing device  30  through a pair of ball bearings  44  and  46 , and serve as the “output shaft” extracting the output torque of the final speed reducing stage to the shaft of the counterpart machine. On the other hand, the connection member  72  to be described later is a member that is further connected to the “independently rotating flange member  66  and the load-side shaft member  70 ”, and is not included in the “member with a minimal structure”. Therefore, in the embodiment, the “output shaft” according to the embodiment of the invention corresponds to the “flange member  66  and the load-side shaft member  70 ”. Furthermore, in the embodiment, since the type of the bearing is the “ball bearing”, the group of members supported by “two bearings” constitute the output shaft, but even one may be independently and stably rotate, for example, when it is supported by a cross roller bearing. For this reason, the term of the “independently rotatable” according to the embodiment of the invention does not mean that it is essentially supported by a pair of bearings. 
     Hereinafter, a configuration will be described in detail in which the stirring shaft  40  of the stirring device  36  is supported by the inline-type speed reducing device  30 . 
     The load-side shaft member  70  and the flange member  66  constituting the output shaft  34  of the speed reducing device  30  are connected to each other in the circumferential direction through a spline engagement portion  71 , and are connected to each other in the axial direction through a spacer  73  and a bolt  75 . 
     The output shaft  34  is directly supported to the casing  84  of the speed reducing device  30  through a pair of ball bearings  44  and  46 . Here, in the opposite-load-side ball bearing  44 , the axial load side of an outer race  44 A comes into contact with a first step portion  84 A of the casing  84  of the speed reducing device  30 , and the opposite load side of an inner race  44 B comes into contact with a step portion  66 A of the flange member  66  (as a part of the output shaft  34 ) through a spacer ring  45 . For this reason, the opposite-load-side ball bearing  44  serves as a thrust bearing that receives a thrust load when a thrust load is applied thereto so that the output shaft  34  moves toward the side of the load (toward the arrow A). 
     Further, in the load-side ball bearing  46  directly supporting the output shaft  34 , the axial opposite load side of the outer race  46 A comes into contact with a second step portion  84 B of the casing  84 , and the axial load side of the inner race  46 B (as a part of the output shaft  34 ) comes into contact with a step portion  70 F of the load-side shaft member  70 . For this reason, the load-side ball bearing  46  serves as a thrust bearing that receives a thrust load when a thrust load is applied thereto so that the output shaft  34  moves toward the opposite side of the load (toward the arrow B). 
     Here, a concept of the “hollow body” as one component of the embodiment of the invention will be described. The “hollow body” of the embodiment of the invention indicates a “body that includes a hollow portion having (a connection member inserted thereto) and rotating along with the output shaft”. That is, the “hollow body” may be present as a part of the “output shaft” or present separately from the “output shaft”. As described above, in the embodiment, the “flange member  66  and the load-side shaft member  70 ” constitutes the output shaft of the embodiment of the invention, but the “load-side shaft member  70 ” is also the “hollow body rotating along with the output shaft”. In other words, in the embodiment, the “load-side shaft member  70 ” constituting a part of the output shaft  34  also serves as the hollow body. 
     Referring to  FIGS. 2 and 3 , a connection member  72  is inserted into a hollow portion  70 A of a load-side shaft member  70  (also serving as the hollow body). The connection member  72  includes a cylindrical portion  72 B that is inserted into the hollow portion  70 A of the load-side shaft member  70 , an upper cover (a protrusion portion)  72 A that protrudes from (the axial opposite-load-side end of) the cylindrical portion  72 B inward in the radial direction to be connected to the stirring shaft  40 , and a ring portion  72 C that is fixed to the axial load-side-end of the load-side shaft member  70 , and is connectable to the load-side shaft member  70  and the stirring shaft  40 . Furthermore, in the embodiment, the ring portion  72 C is integrally formed with the cylindrical portion  72 B, but may be formed separately from the cylindrical portion  72 B and be fixed thereto. 
     Specifically, the load-side shaft member  70  and the connection member  72  are fixed to each other by a bolt  74  while the ring portion  72 C of the connection member  72  comes into contact with the axial end of the load-side shaft member  70 . Further, the stirring shaft  40  and the connection member  72  are fixed to each other by a bolt  76  penetrating them while an upper end surface  40 A of the stirring shaft  40  and the upper cover  72 A of the cylindrical portion  72 B of the connection member  72  face each other with a gap therebetween. Furthermore, the gap may not be present (so that they come into contact with each other). 
     Furthermore, the load-side shaft member  70  and the connection member  72  may be sufficiently fixed to each other and the connection member  72  and the stirring shaft  40  may be sufficiently fixed to each other by the bolts  74  and  76 . However, in the embodiment, the bolts  74  and  76  are mainly used for fixing in the axial direction, and a separate fixing member is prepared for fixing in the circumferential direction. That is, the outer periphery of the connection member  72  is provided with a first key engagement portion K 1  that includes a key  78  and key grooves  70 K 1  and  70 K 2  used for the connection member  72  to receive rotational torque from the load-side shaft member  70 , and the connection member  72  and the load-side shaft member  70  are connected to each other in the circumferential direction through the first key engagement portion K 1 . Further, the inner periphery of the connection member  72  is provided with a second key engagement portion K 2  that includes a key  82  and key grooves  72 K 2  and  40 K 2  used for the connection member  72  to transmit the rotational torque to the stirring shaft  40 , and the connection member  72  and the stirring shaft  40  are connected to each other in the circumferential direction through the second key engagement portion K 2 . Furthermore, as shown in  FIG. 3 , the first key engagement portion K 1  and the second key engagement portion K 2  are deviated from each other by 180° in the circumferential direction. 
     With this configuration, consequently, the connection member  72  is inserted into the hollow portion  70 A of the load-side shaft member  70  to be connected to the load-side shaft member  70  in both axial and circumferential directions and be also connected to the stirring shaft  40  in both axial and circumferential directions. 
     Furthermore, returning to  FIG. 1 , the casing  84  of the speed reducing device  30  is connected to a connection casing  88  through a bolt  86 , and is connected to the tank  38  of the stirring device  36  in a manner such that a bolt (not shown) is inserted into a bolt hole  88 A of the connection casing  88 . 
     Next, an operation of the inline-type speed reducing device  30  will be described. 
     The low-speed rotation (of the final speed reducing stage) extracted from the flange member  66  (as a part of the output shaft  34 ) is transmitted to the load-side shaft member  70  (as a part of the output shaft  34  and the hollow body) through the bolt  75 . The load-side shaft member  70  is connected to the connection member  72  in the axial direction through the bolt  74 , and is connected thereto in the circumferential direction through the first key engagement portion K 1 . Further, the connection member  72  is connected to the stirring shaft  40  in the axial direction through the bolt  76 , and is connected thereto in the circumferential direction through the second key engagement portion K 2 . For this reason, consequently, the stirring shaft  40  is coaxially integrated with the output shaft  34  in the circumferential and axial directions, rotates along with the output shaft  34  at the same speed, and may stir a liquid inside the tank  38 . Since the first key engagement portion K 1  and the second key engagement portion K 2  are deviated from each other by 180° in the circumferential direction, excessive rotational torque does not occur only at a part of the connection member  72  in the circumferential direction, and durability of the connection member  72  may improve. 
     When the own weight of the stirring shaft  40 , that is, the thrust load of moving the output shaft  34  toward the load (toward the arrow A) is applied to the output shaft  34 , the step portion  66 A of the flange member  66  comes into contact with the axial opposite load side of the inner race  44 B of the opposite-load-side ball bearing  44  through the spacer ring  45 , and at the same time, the axial load side of the outer race  44 A of the ball bearing  44  comes into contact with the first step portion  84 A of the casing  84 . Accordingly, the thrust load applied toward the load is received by the casing  84 . Further, when a stirring reaction force is applied to the stirring shaft  40 , so that a thrust load is applied to the output shaft  34  to raise the stirring shaft  40  and moves the output shaft  34  toward the opposite side of the load (toward the arrow B), the step portion  70 F of the load-side shaft member  70  comes into contact with the axial load side of the inner race  46 B of the load-side ball bearing  46 , and at the same time, the axial opposite load side of the outer race  46 A of the ball bearing  46  comes into contact with the second step portion  84 B of the casing  84 . Accordingly, the thrust load applied toward the opposite side of the load is also received by the casing  84 . 
     Since the speed reducing device  30  according to the embodiment has a configuration in which the input shaft  32 , the planetary gear speed reducing mechanism  48 , the output shaft  34 , and the stirring shaft  40  are all coaxially disposed (as an inline), the overall radial dimension of the device is compact, and the axial rigidity of the casing  84  is high. For this reason, the thrust load transmitted from the stirring shaft  40  may be sufficiently received by the casing. That is, it is not necessary to change a design so that the thickness of the casing  84  of the speed reducing device  30  is intentionally increased in order to receive the reaction force against the thrust load, and even when the thickness needs to be increased, the thickness may be minimally increased. 
     At the time of assembling the connection member  72  and the stirring shaft  40 , only the axis of the output shaft  34  with respect to the casing  84  is a base and the coaxial degree between the output shaft  34  and the stirring shaft  40  is included in the level of the manufacturing error of the connection member  72  and the stirring shaft  40 , so that extremely high precision may be maintained. The assembly is extremely simple, and no particular effort or skill is needed to ensure the precision of the axis of the output shaft  34 , the connection member  72 , and the stirring shaft  40 . Further, the number of components such as a bearing may be decreased. 
     Furthermore, in the embodiment, the load-side shaft member  70  and the flange member  66  constituting the output shaft  34  are formed as separate members, and the load-side shaft member  70  constitutes a part of the output shaft  34  and also serves as the hollow body. Accordingly, when the load-side shaft member  70  is changed into a shape matching the size of (another) stirring shaft, the shafts of various counterpart machines (other than that of the embodiment) may be flexibly handled. Further, when the load-side shaft member  70  is replaced by, for example, a general solid shaft, a general speed reducing device (instead of a type of receiving such a thrust load) maybe easily configured. Further, since the load-side shaft member  70  serves as the output shaft  34  and the hollow body, it is possible to prevent an increase in the number of components. 
     Furthermore, in the embodiment of the invention, various variations may occur from this point. 
     First, in the above-described embodiment, since the load-side shaft member  70  and the flange member  66  constituting the output shaft  34  are separately formed (as separate members), the flexibility of the application of the speed reducing device  30  may be ensured. However, in the invention, the output shaft may also be formed as a single member. In this case, the number of components may be further decreased, and the overall speed reducing device  30  may be further decreased in size. Further, since the manufacturing errors of the plurality of members are not accumulated compared to the case where a plurality of members constitutes the output shaft, naturally, the axis of the output shaft becomes stable, so that the assembly precision of the shaft of the counterpart machine may further improve. 
     Further, in the above-described embodiment, although the connection member  72  includes the cylindrical portion  72 B that is inserted into the load-side shaft member  70  (as the hollow body), the upper cover (protrusion portion)  72 A that protrudes from the cylindrical portion  72 B inward in the radial direction to be connected to the stirring shaft  40 , and the ring portion  72 C that is fixed to the axial end of the load-side shaft member  70 , in the invention, the specific shape or configuration of the connection member is not limited to this example. That is, the connection member may be connected to the hollow body and the shaft of the counterpart machine when being inserted into the hollow portion of the hollow body. For example, the connection may be performed in a manner such that a bolt or a pin member penetrates a part (the cylindrical portion  72 B and the like) of the connection member in the radial direction up to the shaft of the counterpart machine. Further, in the above-described embodiment, the connection member  72  is attached with the upper cover  72 A, and the upper cover  72 A serves as the “protrusion portion” of the connection member  72 . That is, the “protrusion portion” may be connected to the shaft of the counterpart machine when protruding from the cylindrical portion  72 B inward in the radial direction, and may not necessarily be formed in the form of a “cover” or a “bottom” at the “end” of the cylindrical portion. 
     Further, in the above-described embodiment, the connection member  72  and the load-side shaft member  70  (as the hollow body) are fixed to each other and the stirring shaft  40  (the shaft of the counterpart machine) and the connection member  72  are fixed to each other by simultaneously performing the “connection in the circumferential direction using the key engagement” and the “connection in the axial direction using the bolt”, but this connection method is not essentially limited to this example. For example, regarding the connection in the circumferential direction between the hollow body and the connection member or the connection member and the shaft of the counterpart machine, the first and second engagement portions may be formed as a spline. Further, the connection in the circumferential direction maybe performed by forming the inner and outer peripheries of the hollow body or the connection member to have a cross-sectional shape (for example, a rectangular cross-section or a so-called D-cut cross-section obtained by cutting a part of the circumference) other than a circle. Further, even in the case of the key engagement, the circumferential phases of the first key engagement portion and the second key engagement portion may not necessarily be 180°. Further, for example, as in the key engagement, the spline engagement, or the key engagement and the bolt engagement, the first engagement portion and the second engagement portion may be formed as different types of engagement members. Further, in the above-described embodiment, different connection members are simultaneously used in the circumferential and axial directions. However, for example, in a connection member using a bolt and the like, the circumferential and connection in the axial directions may be simultaneously performed. 
     Further, in the invention, the configuration of the specific speed reducing mechanism of the speed reducing device is not particularly limited. For example, in the above-described embodiment, the oscillational internal meshing planetary gear speed reducing mechanism  48  is adopted in which the eccentric bodies  54  and  56  are disposed at the outer periphery of the input shaft  32  disposed at the center of the speed reducing device  30  in the radial direction in order to configure the inline-type speed reducing device in which the output shaft  34  is coaxial with the input shaft  32 . However, a speed reducing device with a oscillational internal meshing planetary gear speed reducing mechanism may be adopted in which the eccentric body is disposed at the shaft offset from the center of the speed reducing device in the radial direction. Further, a speed reducing device with a simple planetary gear speed reducing mechanism may be adopted. When the speed reducing device according to the embodiment of the invention is configured as an inline-type, the hollow body rotating along with the output shaft is provided, and a design may be easily provided in which various types of output shafts of various speed reducing mechanisms reasonably receive a thrust load of a shaft of a counterpart machine with a decreased size due to the design of the hollow body. 
     Furthermore, the speed reducing device according to the embodiment of the invention is not essentially limited to the inline-type speed reducing device in which the input shaft and the output shaft are coaxially disposed, and the assembled speed reducing mechanism may not be the inline-type speed reducing mechanism. 
     Hereinafter, a speed reducing device  130  according to such a configuration example will be described by referring to  FIG. 5 . 
     The speed reducing device  130  also has a configuration in which one end side of an output shaft  134  is received in a casing  184  of the speed reducing device  130  and the other end side of the output shaft  134  is connected to a stirring shaft (a shaft of a counterpart machine) to receive a thrust load applied from the stirring shaft through the output shaft  134 . 
     An output shaft  152  of a motor  150  also serves as an input shaft  132  of the speed reducing device  130 . The power input to the input shaft  132  is reduced by a speed reducing mechanism  148  configured as two-stage parallel speed reducing mechanism. The speed reducing mechanism  148  includes a first parallel shaft speed reducing stage  148 C including a first pinion  148 A and a first gear  148 B, and a second parallel shaft speed reducing stage  148 F including a second pinion  148 D and a second gear  148 E. 
     Regarding a configuration in which the output shaft  134  and the stirring shaft  140  as the shaft of the counterpart machine are connected to each other through a connection member  172  to receive a thrust load, in the above-described embodiment, the output shaft  34  includes the flange member  66  and the load-side shaft member  70 , but the embodiment is different from the above-described embodiment in that the output shaft  134  formed as a single member is adopted. The other configurations are the same as those of the above-described embodiment. For this reason, in  FIG. 5 , the same reference numeral with the same last two digits is given to the member which is the same or similar to that of the above-described embodiment in function. 
     That is, even in the embodiment, bearings  144  and  146  are provided which are capable of directly supporting the output shaft  134  to be rotatable and receiving a thrust load applied to the output shaft  134 . Then, the output shaft  134  also serves as the “hollow body including the hollow portion  170 A and rotating along with the output shaft  134 ” (this point is the same as that of the above-described embodiment). Further, the embodiment is the same as that of the above-described embodiment in that the connection member  172  is inserted into the hollow portion  170 A to be coaxially connected to the output shaft  134  as the hollow body and be coaxially connected to the stirring shaft  140 , and the thrust load applied from the stirring shaft  140  to the output shaft  134  through the connection member  172  is received by the bearings  144  and  146 . 
     The speed reducing device  130  is the “speed reducing device of which one end side of the output shaft  134  is received in the casing  184  of the speed reducing device  130  and the other end side of the output shaft  134  is connected to the stirring shaft  140  to which the thrust load is applied”, and as described above, the speed reducing device has a basic structure in which the design of the connection structure is very difficult. However, in the invention, the speed reducing device  130  with such a structure may be embodied without causing any problem, and the original operation and effect of the invention may be obtained. 
     As described above, the invention may be applied to any type of a speed reducing mechanism when a speed reducing device is provided of which one end side of an output shaft is received in a casing of the speed reducing device and the other end side of the output shaft is connected to a shaft of a counterpart machine to which a thrust load is applied. 
     Here, the other end side of the output shaft may be disposed in an opening of the casing so as to be connected to the shaft of the counterpart machine, and may not protrude from the casing in the axial direction. 
     According to the embodiment, although the cheap first and second parallel shaft speed reducing stages  148 C and  148 F are used in the speed reducing mechanism  148 , since the input shaft  132  and the output shaft  134  are not largely offset from each other, there is a practical merit in that the radial size of the speed reducing device  130  may be decreased. 
     Furthermore, in the above-described embodiment, the pair of ball bearings  44  ( 144 ) and  46  ( 146 ) directly supporting the output shaft  34  ( 134 ) is configured to receive the thrust load from the stirring shaft  40  ( 140 ), but the invention may not have a configuration in which all bearings directly supporting the output shaft receive the thrust load from the shaft of the counterpart machine. For example, in the above-described embodiment, when a stirring reaction force applied from a liquid is not large and the output shaft  34  ( 134 ) receives only the thrust load in the direction depicted by the arrow A, only one bearing may receive the thrust load, and the other bearing (not receiving the thrust load) may be formed as a general bearing. In this case, any one of the load-side and the opposite-load-side bearing may receive the thrust load in any direction. 
     The invention is particularly effective in a structure in which the output shaft of the speed reducer of the above-described embodiment is disposed downward so that the shaft of the counterpart machine is hung thereon, but the invention is not limited thereto. For example, the invention may be applied to a case where the output shaft of the speed reducer is disposed in, for example, the horizontal direction instead of the downward direction. In this case, the connection between the hollow body and the connection shaft and the connection between the connection shaft and the shaft of the counterpart machine may be performed by at least the engagement in the rotational direction, and fixing in the axial direction is not essential. 
     The invention is not limited to the stirring device, but may be widely applied to a device in which a thrust load is applied from a shaft of a counterpart machine to an output shaft. For example, the invention may be applied to an extruder. 
     It should be understood that the invention is not limited to the above-described embodiment, but may be modified into various forms on the basis of the spirit of the invention. Additionally, the modifications are included in the scope of the invention. 
     FIG. 1 
       30 : SPEED REDUCING DEVICE 
       32 : INPUT SHAFT 
       36 : STIRRING DEVICE 
       34 : OUTPUT SHAFT 
       66 : FLANGE MEMBER 
       70 : LOAD-SIDE SHAFT MEMBER 
       72 : CONNECTION MEMBER