TWI399498B - Decelerating device - Google Patents

Description

Speed reducer

The present application claims priority based on Japanese Patent Application No. 2009-63211, filed on March 16, 2009. The entire contents of this application are incorporated by reference in this specification.

The invention relates to a reduction gear.

Patent Document 1 discloses a speed reducer 30 as shown in FIG.

FIG. 8 is a longitudinal sectional view of the speed reducer 30.

The speed reducer 30 includes an input shaft 32, an eccentrically oscillating rotation around the input shaft 32, a gear 34 having a slight difference in the number of teeth from the external gear 34, and being fixed to the outer casing 36 and internally meshed with the external gear 34. The internal gear 38 is disposed on the first and second support blocks 40 and 41 on both axial sides of the external gear 34. In this example, the eccentric body shaft 50 penetrates the external gear 34 in the axial direction, and the relative rotation of the internal gear 38 and the external gear 34 is transmitted to the first support block 40 and the second support block 41.

The first support block 40 and the drive pin 68 are strongly coupled by a segment 68B of the drive pin 68 and a bolt (not shown). Further, the second support block 41 and the drive pin 68 are strongly coupled by the segment 68C of the drive pin 68 and the flanged bolt 77. Thereby, the first and second support blocks 40 and 41 do not fall off from the outer casing 36 during normal operation. However, in the event that the drive pin 68 or the flanged bolt 77 is broken, the first support block 40 is detached from the outer casing 36. Therefore, the following countermeasures are employed in this conventional example.

On the end portion 36A (the left end portion of Fig. 8) of the outer casing 36, a plate 70 having a projection 70A is provided. A convex opposing portion 40A opposed to the protruding portion 70A is formed in the first support block 40. The outer diameter d1 of the opposing portion 40A is set larger than the inner diameter D1 of the protruding portion 70A. That is, a part of the protrusion 70A and the opposite portion 40A overlap each other when viewed from the axial direction. Thereby, even if the drive pin 68 or the flanged bolt 77 is broken, the first support block 40 can be prevented from coming off the outer casing 36 by the engagement of the projection 70A and the opposing portion 40A.

That is, as a type of speed reducer in which the outer casing is fixed and the shaft inside the outer casing (for example, the output shaft) rotates, even if the inside of the reduction gear is broken, the protruding portion can be structurally prevented from being integrated with the shaft. The outer casing is separated to prevent it from falling out of the outer casing.

Patent Document 1: Japanese Patent Laid-Open No. 2004-138094 (Request Item 1, Fig. 1)

However, in the case where the second support block 41 is fixed and the rotating structure is taken out from the outer casing 36, if the drive pin 68 or the flanged bolt 77 is broken, the outer casing 36 itself is dropped together with the first support block 40.

The present invention has been developed in order to solve such a problem, and an object of the present invention is to prevent a rotating casing from being rotated or to include a rotating casing, in particular, in a rotating reduction gear that is taken out from a casing, even if a connecting member such as a driving pin is broken. Most of the reducer is detached, thereby improving the safety of the reduction gear.

In order to solve the above problems, the reduction gear device of the present invention includes: an annular member provided in the outer casing; an inner member that is inscribed in the annular member; and first and second support blocks disposed on both axial sides of the inner member; a connecting member that connects the first and second support blocks; the first support block is fixed to the fixing portion, and is taken out from the outer casing, and at least a part of the outer casing and the fixed portion or the first support block have a gap therebetween The way they are opposite each other.

In the present invention, the first support block is fixed to the fixing portion, and is taken out from the outer casing, and the rotating outer casing and the fixed portion or the first support block face each other with a gap therebetween.

Thereby, when the connection member is broken, the deceleration device for taking out the rotation from the outer casing can face the housing portion and the fixing portion or the first support block with a gap therebetween, and the outer casing can be used with the opposite portion. The fixing portion or the first support block is caught to prevent the entire reducer from coming off.

Further, the outer casing and the fixed portion or the first support block have a gap capable of generating a labyrinth effect, whereby the inflow of dust or coolant can be prevented.

According to the present invention, the structure is not complicated, and even if a part of the speed reducer (the joint member) is broken by applying a strong impact, the rotation of the outer casing or the reducer including the rotary casing can be prevented from being detached, thereby Improve the safety of the gear unit.

In order to understand the use of the reduction gear 300, the automatic tool change device 1 will first be described for convenience.

5 to 7 show an overall schematic perspective view of the automatic tool change device, a longitudinal sectional view of the drive device of the automatic tool change device, and a front view of the tool.

The automatic tool changer 1 such as a machining center automatically performs the work of replacing the required tool 4 from the tool set 3 having a plurality of tools 4 on the outer circumference and replacing it with the tool 4 attached to the head 5.

The automatic tool changer 1 includes a tool holder 3 in which a plurality of tools 4 are provided in a casing 2. The tool cymbal 3 is formed in a disk shape, and different kinds of tools 4 are radially arranged. And the tool holder 3 can be rotated by the motor 10 mounted on the tool holder 3.

On the other hand, the automatic tool changer 1 has a head 5 for transmitting power to the tool 4. And the head 5 can advance and retreat in the up and down direction (up and down direction in FIG. 5), and the tool 4 can be transferred from the tool 匣3.

According to the above configuration, the head 5 selects the appropriate tool 4 based on the object to be processed and the processing content (not shown), and performs machining (for example, drilling, cutting, etc.).

The first support block 314 and the fixing portion 308 are coupled by bolts 328, whereby the speed reducer 310 and the fixing portion 308 are fixed together. Further, the tool holder 3 is coupled to the opposite side of the fixed portion of the speed reducer 310 so as to further shield the cover 320 of the speed reducer 310. The tool holder 3 is coupled and fixed to the housing 317 by a bolt 380 provided on the outer casing 317 of the reduction gear 310.

The speed reducer 310 is a so-called oscillating internal mesh type planetary gear reducer that outputs power from the outer casing 317. As a result, the tool body 171 integrated with the outer casing 317 by the bolt 380 is rotated.

In the above-described automatic tool changer, the dust and the coolant (cutting oil) are scattered along with the processing, and the dust and the coolant enter the inside of the speed reducer 300.

Next, the structure of the reduction gear transmission 300 according to an embodiment of the present invention will be described.

Fig. 1 is a longitudinal sectional view showing a reduction gear transmission 300 according to a first embodiment of the present invention. In addition, FIG. 2 is an enlarged view showing a surface of the circular plate 319 and the first support block 314 which are disposed to prevent the reducer from falling off in the axial direction.

First, the schematic structure of the reduction gear device 300 will be described.

The speed reducer 300 is mainly composed of a speed reducer 310 and a fixing portion 308 to which a drive source (not shown) of the speed reducer 310 is attached.

Further, reference numeral 302 denotes a concave portion into which a motor shaft (not shown) of a motor (drive source) is inserted.

The output shaft (motor shaft) of the motor is coupled to the relay shaft 303 provided in the fixed portion 308. The pinion gear 304 formed at the front end of the relay shaft 303 by direct cutting is meshed with the helical gear (bevel gear) 307. The helical gear 307 is coupled and fixed to one end of the input shaft 311 of the speed reducer 310 by a bolt 305. Furthermore, the axis O2 of the pinion gear 304 and the axis O1 of the helical gear 307 form a predetermined angle A.

The structure of the speed reducer 310 is as follows.

The speed reducer 310 of the present embodiment has an internal gear (annular member) 313 provided in the rotating casing (housing) 317, a gear (inner member) 312 which is inscribed in the internal gear 313, and is disposed in the axial direction of the external gear 312. The first and second support blocks 314 and 315 on both sides and the inner pin (connection member) 323 that connects the first and second support blocks 314 and 315.

The "rotating outer casing 317" of the present invention is defined not only by the rotating outer casing 317 but also by a member integrally fixed to the rotating outer casing 317 like the circular plate 319 in the embodiment.

The external gear 312 is in meshed with the internal gear 313 while being swung, and the rotation of the external gear 312 is restrained, and the output (described later) is taken out from the rotating casing 317 provided with the internal gear 313.

Three eccentric bodies 326 (326A, 326B, 326C) are integrally formed on the input shaft 311. The external gear 312 is assembled through the rollers 334 (334A, 334B, 334C) around the outer periphery of the eccentric body 326.

Further, the eccentric phases of the eccentric bodies 326 are respectively shifted by 120 degrees, and the eccentric phase difference of the external gear 312 is 120 degrees.

The outer gear 312 has a slightly smaller number of teeth than the inner gear 313. Further, the outer gear 312 has an inner pin hole 325 that penetrates the outer gear 312. The inner pin 323 is loosely fitted in the inner pin hole 325.

On the other hand, the internal gear 313 is constituted by a pin (roller) 340 which is rotatably mounted on the inner circumference of the rotary casing 317.

The first and second support blocks 314 and 315 are disposed on the axial fixed portion 308 side (drive source side) of the external gear 312 and the opposite side of the fixed portion (the drive source opposite side). In the present embodiment, the first support block 314 on the side of the drive source (electric motor), that is, on the side of the fixed portion 308 is fixed to the fixed portion 308 by a bolt 328. The inner pin 323 is integrally formed on the first support block 314 (there are a plurality of ones in the circumferential direction, but only one is shown). The inner pin 323 is coupled and fixed to the disk-shaped second support block 315 by bolts 316. In other words, the inner pin 323 restrains the rotation of the external gear 312 and functions as a connecting member that connects the first and second support blocks 314 and 315.

Further, an inner roller 324 as a slide facilitating member is attached to the outer circumference of the inner pin 323.

Next, a mechanism for preventing the falling of the speed reducer 310 and preventing the inflow of dust or the like will be described.

In the present embodiment, the rotating casing 317 (more specifically, the circular plate 319 coupled to the rotating casing 317 by the bolts 318) and the first supporting block 314 are opposed to each other with the gap 350.

First, the configuration in which the circular plate 319 and the first support block 314 are opposed to each other will be described.

A circular plate 319 is provided through the bolt 318 at the end of the rotating casing 317 on the axial fixing portion 308 side of the rotating casing 317. The circular plate 319 has a protruding portion 319J that protrudes radially inward from the rotating casing 317. Further, the cover 320 attached to the opposite side of the fixed portion of the reduction gear 300 is fixed to the rotating casing 317 by bolts 321 . The breaking stress of the bolt 318 that fixes the circular plate 319 fixed to the rotating casing 317 is set to be larger than the breaking stress of the bolt 321 that fixes the cover 320 on the opposite side of the fixed portion of the reduction gear 300. This is because when the inner pin 323 is broken, the weight of the rotating outer casing 317 and the second supporting block supported by the bolt 318 is larger than the weight of the second supporting block 315 supported by the bolt 321 .

A step portion 314B is formed at an end portion of the fixing portion 308 on the first support block 314 side, and an inner peripheral portion 319C of the circular plate 319 faces the step portion 314B. The circular plate 319 is provided on a surface P1 that intersects with the axis O1 of the rotating casing 317, and has a first surface 319A that faces the opposite side of the driving source.

On the other hand, the first support block 314 has a second surface 314A that faces the drive source side and faces the first surface 319A in a non-contact manner in the vicinity of the outer periphery of the end portion on the axial drive source side.

Since the outer diameter d1 of the first support block 314 having the second surface 314A is larger than the inner diameter D1 of the circular plate 319 having the first surface 319A, the first surface 319A and the second surface 314A overlap when viewed in the axial direction.

Further, the circular plate 319 integrated with the rotating casing 317 has a gap 350 with the fixed portion 308 and the first support block 314. The gap 350 forms a section surrounding the outer periphery of the end portion of the circular plate 319 in the present embodiment. Font to get a maze effect. The width X of the gap 350 is determined according to the type of the coolant and the size of the dust, depending on the inner diameter of the circular plate 319 and the axial thickness.

A washer 327 having a gap in the circumferential direction between the rotating casing 317 and the circular plate 319 is engaged with the bolt 318.

Further, a bearing 322A is disposed between the first support block 314 and the input shaft 311, and a bearing 322C is disposed between the second support block 315 and the input shaft 311, and is disposed between the first support block 314 and the rotary housing 317. In the bearing 322B, a bearing 322D is disposed between the second support block 315 and the rotary housing 317.

In the present embodiment, the first support block 314 on the drive source side is fixed to the fixed portion 308. Further, since the first support block 314 is connected and fixed to the second support block 315 by the integrally formed inner pin 323, the inner pin 323 and the second support block 315 are also coupled and fixed to the fixed portion 308.

Next, the action of the speed reducing device 300 will be described.

When a rotation instruction is input to a motor (drive source) not shown, the motor shaft rotates by the amount (angle) indicated. The rotation of the motor shaft is transmitted to the pinion gear 304 through the relay shaft 303, and is further transmitted to the helical gear 307 that meshes with the pinion gear 304. Since the helical gear 307 is coupled and fixed to the input shaft 311 of the speed reducer 310, the input shaft 311 is rotated.

When the input shaft 311 rotates, the eccentric body 326 formed on the input shaft 311 rotates. As a result, the gear 312 is oscillated and rotated by the roller 334 outside the outer circumference of the eccentric body 326. In the present embodiment, the inner pin 323 passes through the outer gear 312, and the inner pin 323 is fixed to the fixing portion 308 through the first support block 314, so that the rotation of the outer gear 312 is restrained. Thereby, the internal gear 313 meshing with the external gear 312 is displaced (rotated) with respect to the external gear 312 by a reduction ratio corresponding to (the difference in the number of teeth between the internal gear 313 and the external gear 312) / (the number of teeth of the internal gear 313). . The rotation of the internal gear 313 is taken out from the rotary housing 317 in which the internal gear 313 is integrally formed.

Further, since the disk 319 is provided in a state in which it is not in contact with the first support block 314 or the fixed portion 308 integrated with the first support block 314, the rotation of the speed reducer 310 during normal operation is not carried out. Come to any impact. On the other hand, the second support block 315 is strongly coupled to the inner pin 323. Therefore, during the normal operation, the second support block 315 and the rotary housing 317 do not fall off from the side of the fixing portion 308 including the first support block 314.

However, in the event of an accident such as a collision, the reducer 310 of such a configuration may have a broken inner pin 323 or bolt 316.

Therefore, there is no special consideration for the fracture. If the inner pin 323 or the bolt 316 is broken, the second support block 315 and the rotating outer casing 317 lose their supporting base and fall off together with the rotating outer casing 317.

However, in the present embodiment, the first surface 319A on the opposite side to the fixed portion in the axial direction of the disk 319 and the second surface 314A on the end surface of the first support block 314 on the side of the fixed portion 308 overlap each other when viewed in the axial direction. Therefore, even if a strong impact is applied and the inner pin 323 or the bolt 316 in the speed reducer 310 is broken, the first surface 319A is caught by the second surface 314A, and the rotating outer casing 317 can be prevented from falling off in structure, so that the speed reducing device can be improved. 300 security. Further, since the cover 320 is provided to shield the second support block 315, secondary damage caused by the fall of the second support block 315 can be prevented.

Further, since the second surface 314A is formed at the end portion of the first support block 314 which is originally separated from the fixed portion 308, the convex and convex engagement is not required, so the first and second faces 319A are The shape of the 314A overlaps in the radial direction, and the problem of flexibility in assembly of the reduction gear 300 and reduction in easiness does not occur.

Further, the circular plate 319 and the fixing portion 308 or the first support block 314 which are coupled to the rotary casing 317 by the bolts 318 are disposed so as to face each other with the gap 350 having the width X in consideration of the size of the dust or the like. Construction. Thereby, the circular plate 319 and the fixed portion 308 or the first support block 314 constitute a labyrinth flow path, and the pressure loss of the fluid to be introduced therein is increased, and the inflow amount is reduced, whereby the sealing effect (maze effect) can be exhibited. As a result, it is possible to prevent the inflow of the dust and the coolant of the object to be processed around the reduction gear 300. Thereby, damage or the like of the oil seal 341 which is closer to the inner side of the speed reducer 310 than the circular plate 319 can be prevented.

Further, between the rotating outer casing 317 and the circular plate 319, the washer 327 is engaged with the bolt 318 to secure a gap in the circumferential direction. Thereby, even if the coolant enters the speed reducer 310 through the step portion 314B, the coolant can be moved downward in the reducer 310 by gravity, and discharged from the circumferential direction secured by the washer 327. It is outside the reducer 310.

The gap in the circumferential direction is adjusted by the thickness T of the washer 327. The width of the gap is set such that the powder cannot enter but the coolant is easily discharged. Therefore, it is determined in consideration of the viscosity of the coolant and the size of the dust.

Based on the above description, the structure is not complicated, and even if a part of the speed reducer 310 is broken due to a strong impact, the rotating housing 317 or the reduction gear 310 including the rotating housing 317 can be prevented from falling off most of the structure. And the powder or liquid is prevented from flowing into the interior, and the safety of the reduction gear 300 can be improved.

That is, with a configuration, it is possible to realize two functions of preventing the falling of the rotating casing 317 and the like and preventing the inflow of the coolant or the like.

Further, in the above-described embodiment, in order to face the first surface 319A and the second surface 314A, the step portion 314B is provided as a space for the disc 319 to face (FIG. 2), but the outer portion of the fixing portion 308 may be designed. The inner circumference D1a of the disk is smaller than the inner surface D1a, whereby the first surface 319a1 and the second surface 314a2 can be opposed without providing a step (Fig. 4(a)). In other words, the step may be provided only on the first support block 314 side or only on the fixed portion 308 side. In the illustrated example, only the step is formed on the fixed portion 308b side, and the second surface 308b2 and the first surface 319b1 are provided here. Oppose each other (Fig. 4(b)).

Further, a concave portion may be formed on the side of the rotating casing 317c or 317d, and a convex portion that enters the concave portion may be formed on the side of the first support block 314c or the fixed portion 308d, and the first surface 317c1 may be formed by opposing the two faces. 317d1, second surface 314c2, 308d2 (Fig. 4 (c), (d)). Further, the convex portions of the first support block 314e or the fixed portion 308f are opposed to the rotating casings 317e and 317f, thereby forming the first faces 319e1 and 319f1 and the second faces 314e2 and 308f2 (Figs. 4(e) and (f). ) Yes. Further, the concave portion may be provided only on the side of the first support block 314g or the fixed portion 308h, and the convex portion that is engaged with the concave portion may be provided on the rotating casing 317, thereby forming the first faces 319g1, 319h1, and 2nd. Faces 314g2, 308h2 (Fig. 4 (g), (h)). The method of forming the first surface and the second surface is not limited to the above example. In particular, when the first surface and the second surface are formed by combining the segment portion, the convex portion, and the concave portion, the convex portion and the concave portion are not necessarily formed to be continuous over the entire circumference, for example, by a convex portion formed radially from the square side. The structure in which the first surface or the second surface is formed may be used.

In the above case, in order to prevent the damage of the oil seal 341 caused by the dust, the oil seal 341 is opposed to the fixed portion 308 side (the opposite side of the drive source). More preferably, they are opposed to each other in such a manner as to have a gap 350 of a width X at which a labyrinth effect can be obtained.

Further, in order to smoothly move the coolant entering the step portion 314B (one portion flows out), the washer 327 is used as a member for securing the gap in the circumferential direction, but it may not be the washer 327 but a specially designed member. Further, it is not necessary to provide a member for ensuring a gap such as the washer 327.

Further, as long as the entire reduction gear unit 310 can be supported when the inner pin 323 is broken, the breaking stress of the two bolts 318 and 321 can be designed to be the same size. However, based on the relationship of the foregoing functions, it is not preferable when the breaking stress of the bolt 321 is larger than that of the bolt 318, that is, the relationship between the magnitude of the breaking stress of the bolts 318 and 321 of the present embodiment.

The present invention is applicable, for example, to the reduction gear unit 400 shown in Fig. 3, for example.

In the speed reducer 400, the power of the motor (drive source) (not shown) is meshed with the helical gear (bevel gear) 407 by the direct cutting of the pinion 404 formed at the tip end of the relay shaft 403, and is transmitted to the input shaft 411. . A drive pinion 430 is formed on the input shaft 411. Also, the drive pinion 430 is simultaneously meshed with the three distribution gears 431 (only one of which is illustrated in FIG. 3). The distribution gear 431 is formed integrally with three eccentric body shafts 432 (only one of which is illustrated in FIG. 3).

The three eccentric body shafts 432 are respectively provided with two sets of six eccentric bodies 426 which are eccentric from the axial center at the same position in the axial direction (only two of the 426A, 426B are illustrated in the illustrated example). The external gear 412 (412A, 412B) is fitted to the eccentric body 426 through a roller 434 (only 434A, 434B is shown).

The first and second support blocks 414 and 415 are disposed on both axial sides of the external gear 412 (on the side opposite to the drive source side and the drive source), and the rotary housing 417 is rotatably supported by the bearings 422B and 422D. The second support block 415 is coupled and fixed to the first support block 414 by a bolt 416 and transmitted through a carrier (connection member) 423. With these configurations, the external gear 412 is in meshed with the internal gear 413 integrally formed with the rotary housing 417 while swinging while being restrained by the rotation.

Also in the present embodiment, when the carrier 423 is broken due to a collision or the like, the same structure as that of the previous embodiment can be employed, and the falling of the rotating casing 417 and the second supporting block 415 can be prevented. Since the configuration itself is the same as the previous embodiment, the same reference numerals are given to the components having the same or similar functions, and the duplicated description is omitted.

Further, the type of the speed reducing device to which the present invention is applicable is not limited. In addition to the oscillating internal engagement type speed reducer, for example, it can also be applied to a housing type rotary type planetary gear type speed reducer; it has a sun gear, a planetary gear (inner member) externally meshed with the sun gear, and the planet The gear is internally meshed with the internal gear (annular member), and the connecting member of the planetary gear is rotatably held.

In addition to the planetary gear type reduction gear unit, the same can be applied to the housing rotary type friction reduction device; it has an annular roller (annular member) integrated with the outer casing, and a planetary roller (inner member) connected to the annular roller, The concave arc-shaped cross section having substantially the same curvature as the outer circumferential surface of the planetary roller and the holding member for rotatably holding the planetary roller from the outer circumferential side can obtain the same operational effects.

Further, in the above-described embodiment, in order to achieve the two effects of the fall prevention and the inflow prevention, the gaps having the labyrinth effect can be opposed to each other, and if the fall prevention effect is achieved, the size of the gap is not a problem.

300. . . Speed reducer

308. . . Fixed part

310. . . Reducer

312. . . External gear (inner member)

313. . . Internal gear (ring member)

314. . . First support block

315. . . Second support block

317. . . Rotating housing (housing)

319. . . Circular plate

323. . . Domestic sales (connection member)

327. . . washer

350. . . gap

Fig. 1 is a longitudinal sectional view showing a reduction gear according to a first embodiment of the present invention.

Fig. 2 is an enlarged view of a portion B of the speed reducer of the first embodiment.

Fig. 3 is a longitudinal sectional view showing a reduction gear according to a second embodiment of the present invention.

4(a) to 4(h) are comparison views of the fall prevention mechanism shown in Fig. 2 and other fall prevention mechanisms.

Fig. 5 is an overall schematic perspective view of an automatic tool changer incorporating a drive unit.

Figure 6 is a longitudinal cross-sectional view showing the driving device of the automatic tool changer of Figure 5;

Figure 7 is a front elevational view of the tool of Figure 6.

Fig. 8 is a longitudinal sectional view showing a conventional speed reducer having a projection inside the reducer.

300. . . Speed reducer

301 (301A, 301B). . . Bearing

303. . . Relay axis

304. . . gear

305. . . bolt

306. . . washer

307. . . helical gear

308. . . Fixed part

309A. . . First joint surface

309B. . . Second joint surface

309C. . . Third joint surface

310. . . Reducer

311. . . Input shaft

312. . . External gear

313. . . Internal gear

314. . . First support block

315. . . Second support block

316. . . bolt

317. . . Rotating shell

318. . . bolt

319. . . Circular plate

320. . . cover

321. . . bolt

322 (322A, 322B, 322C, 322D). . . Bearing

323. . . Domestic sales

324. . . Inner roller

325. . . Inner hole

326 (326A, 326B, 326C). . . Eccentric body

327 (327A, 327B, 327C). . . washer

328. . . bolt

334 (334A, 334B, 334C). . . Roller

340. . . Export

341. . . Oil seal

Claims (7)

A housing rotation type speed reduction device includes: an annular member provided to the outer casing; an inner member that is inscribed in the annular member; and first and second support blocks disposed on both axial sides of the inner member, and the connecting portion A connecting member for a second supporting block, wherein the first supporting block is fixed to the fixing portion and is taken out from the outer casing, and the outer casing and the fixing portion or the first supporting block are at least A part of each other opposes each other with a gap. The outer casing rotary type speed reducer according to claim 1, wherein the outer casing has a first surface formed on a surface opposite to a shaft of the outer casing and opposite to a drive source of the outer casing; the first support block has a The first surface faces the second surface of the crucible in a non-contact manner. The outer casing rotary type speed reducer according to claim 1, wherein a step portion is formed at an end portion of the fixing portion on the first support block side. The outer casing rotary type reduction gear according to any one of the items 1 to 3, wherein the end portion of the outer casing on the axial drive source side is fixed: has a radially inner side protruding from the outer casing a disc of the protruding portion; the protruding portion of the disc is opposed to the fixing portion or the first supporting block so as to have a gap therebetween. The outer casing rotary type reduction gear of claim 4, wherein a member for ensuring a gap is disposed between the outer casing and the circular plate. The outer casing rotary type reduction gear of claim 5, wherein the circular plate is fixed to the outer casing by a bolt, and between the outer casing and the circular plate, a washer is provided on the bolt, and the The function of the member of the aforementioned gap can be ensured. The outer casing rotary type reduction gear of claim 4, wherein the circular plate is fixed to the outer casing by bolts, and a cover on a side opposite to a driving source of the reduction gear is fixed to the outer casing by bolts, and the foregoing The breaking stress of the bolt of the circular plate is set to be larger than the breaking stress of the bolt of the cover on the opposite side to the driving source of the aforementioned reduction gear.