JPH0553979B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a transmission device used in a control device such as an industrial robot whose rotational direction is switched between forward and reverse during operation.

[Prior art]

In control equipment such as industrial robots, the direction of rotation is not limited to only one direction, but is operated while being switched between forward and reverse directions at any time. On the other hand, gears in transmissions installed in such control devices always have backlash, and because of this backlash, each time the direction of rotation is switched between forward and reverse, the amount of rotation is delayed by the amount of backlash, resulting in inaccurate transmission. This problem has been pointed out.

Conventionally, in order to eliminate the inaccuracy of transmission due to such backlash, a mechanism has been proposed in which gears are stacked double, the phase is shifted by the amount of backlash, and the two tooth surfaces mesh with each other with 0 backlash. . However, since errors inevitably occur in the backlash due to machining, fixing the two gears to the shaft with a phase shift by the backlash having such a minute error will result in poor indexing accuracy during the work. This is extremely difficult from above.

Furthermore, since the gear is in two-tooth mesh, the inevitable wedge effect that will occur in the future is inevitable, making smooth operation difficult.

[Purpose of the invention]

An object of the present invention is to provide a star gear mechanism or a planetary gear mechanism with a mechanism that is simple in structure and easy to operate, so that a rotation delay equivalent to backlash occurs when switching the rotation direction of the transmission shaft between forward and reverse. First, it is an object of the present invention to provide a control transmission that enables smooth power transmission by equally distributing power to a plurality of gear trains.

[Structure of the invention]

The present invention, which achieves the above object, comprises a star gear mechanism or a planetary gear mechanism in which an even number of intermediate gears 8a, 8b, . . . are interposed between the sun gear 5 and the internal gear 7, and the intermediate gears 8a, 8b... is supported on the floating intermediate wheel 13 through a looser which can generate an oil film, and the floating intermediate wheel is pivotally supported on the intermediate shafts 9a, 9b..., and connected and fixed eccentrically to the shaft ends of the intermediate shafts. By rotating the tapered shaft 10, the intermediate shafts 9a, 9b... can be adjusted to move clockwise and counterclockwise along a substantially circumferential direction centered on the axis of the sun gear. , the slotted annular stator 15 can be fixed on the casing 3 or the carrier through a tight fit, and when the sun gear and the internal gear have stopped rotating, the slotted annular stator is loosened to clock half of the intermediate shafts. direction, and by rotating the other half of the intermediate shafts counterclockwise, the sun gear and internal gear of the half of the intermediate gears are brought into a state of backlash elimination in the forward rotation direction, and at the same time, the remaining half of the intermediate shafts are rotated counterclockwise. The gear train of the sun gear and the internal gear of the intermediate gear is brought into a state of backlash elimination in the reverse direction, and in this state, the slotted annular stator is tightly fitted to fix the tapered shaft. It is something.

〔Example〕

FIGS. 1 and 2 show an example of a control transmission according to the present invention using a star gear mechanism having four even numbered intermediate gears.

In these figures, 1 is an input shaft, 2 is an output shaft, and 3 is a casing. The input shaft 1 is rotatably supported by one bearing part 4 of the casing 3,
A sun gear 5 is fixed to its inner end. On the other hand, the output shaft 2 is rotatably supported by the other bearing 6 of the casing 3, and has an internal gear 7 fixed to its inner end. Between the sun gear 5 and the internal gear 7, an even number (four in this embodiment) of intermediate gears 8a, 8b, 8c, and 8d distributed at equal intervals are meshed, forming a star-shaped gear mechanism. are doing. In this embodiment, a sun gear 5, an internal gear 7, intermediate gears 8a, 8b, 8
c and 8d are both spur gears.

The intermediate shafts 9a, 9b, 9c, 9d for supporting the intermediate gears 8a, 8b, 8c, 8d are supported via floating intermediate wheels 13, . . . , 13, respectively. , ..., 13 are rotatably supported on intermediate shafts 9a, 9b, 9c, and 9d via bearings. These floating intermediate gear wheels 13,..., 13 and intermediate gears 8a, 8b, 8c,
8d, there is a gap 14 in which an oil film can be formed. In Figures 1, 2, and 3, the above play
14 is exaggerated and shown in a large size for the purpose of explaining the effect described later, but in reality, the extremely small amount that is optimal for the generation of an oil film is between .

The intermediate shafts 9a, 9b, 9c, and 9d have tapered shafts 10 and 9d with their ends eccentrically disposed by a distance e.
. . , 10 and screws 11, . That is, the annular stator 15
The annular stator 15 has a tapered inner surface and a cut 16 along the axial direction as shown in FIG.
By tightening the nut 12 screwed into 1, the tapered shaft 10 is expanded in the radial direction by rubbing the tapered surfaces together and opening the cut 16, and the resulting wedge effect securely fixes the tapered shaft 10 to the casing 3. It's becoming like that.

Further, when the annular stator 15 is loosened, the tapered shaft 10 can rotate in either the left or right direction of the F direction and the G direction, as shown in FIG. 9a, 9b, 9c,
9d can be moved and adjusted left and right in the F direction and the G direction about the axis of the tapered shaft 10.

In such a configuration, by operating the movement adjustment mechanism consisting of the taper shaft 10 and the like, it is possible to set the gear in a state in which backlash is eliminated as follows.

That is, first, the sun gear 5 and the internal gear 7 are locked in a non-rotating state, and the annular stator 15 is loosened to place the tapered shaft 10 in an unlocked state.
In this state, as shown in FIG. 2, the two intermediate shafts 9a and 9b, which are diagonally opposite to each other, are rotated in the direction of arrow F by rotating the tapered shafts 10 and 10 that are integrated with these intermediate shafts until they come to a stop. , and the remaining two intermediate axes 9c and 9d, which are also diagonally related, are
By rotating the tapered shafts 10, 10, which are integral with these, they are rotated in the direction of arrow G, which is opposite to the direction of arrow F, until they come to a stop.

Due to such rotation of the intermediate shafts 9a, 9b, 9c, and 9d, the intermediate gears 8a, 8b, 8c, and 8d are
Each rotates around the axis of the tapered shaft 10, but since the amount of rotation is a small distance equivalent to a backlash, it can be regarded as a rotation along the circumferential direction around the axis of the sun gear 5. be able to. Therefore, the intermediate gears 8a, 8b and 8c, 8
d means that when the former 8a and 8b rotate in the F direction and the latter 8c and 8d rotate in the G direction, the contact with the tooth surface of the sun gear 5 and the contact with the tooth surface of the internal gear 7 are the first. The process stops when the state shown in FIG. 2 is reached, that is, when the backup is erased.

When the rotation is stopped in this way, the tooth contact state of the gear train of the intermediate gears 8a and 8b rotated in the F direction, that is, the gear train of the intermediate gears 8a and 8b and the sun gear 5 and the internal gear 7, is the same as that of the sun gear. 5 is in contact in the direction of rotation in the counterclockwise direction R.
In addition, a gear train consisting of the other intermediate gears 8c and 8d,
That is, the gear train of the intermediate gears 8c and 8d, the sun gear 5, and the internal gear 7 are in contact with each other in the direction in which the sun gear 5 rotates in the clockwise direction C. When you reach a situation like this,
The nut 12 on the screw 11 is tightened and the tapered shaft 10 is locked by the annular stator 15 as described above. Next, the sun gear 5 and the internal gear 7 are unlocked to enable operation.

Note that in another embodiment shown in FIG. 5, the intermediate shaft 9
This is an example in which the diameters of a, 9b, 9c, and 9d are larger than that of the tapered shaft 10, and they are supported at both ends, which is advantageous when the load is large. The same tooth contact condition can be set by operation.

The tapered shaft 10 locked as described above is extremely firmly fixed due to the wedge effect of the annular stator 15, and will not be easily released. That is, since the tapered shaft 10 and the intermediate shaft are in an eccentric relationship, a large rotational moment is always generated in the tapered shaft 10, but such rotational moment is suppressed by the fixation by the wedge effect. This enables stable transmission of even large loads.

The tapered shaft 10 firmly locked in this way
The lock cannot be easily released, but it is necessary to release the lock in order to readjust the settings. For this purpose, a screw 17 is cut on the outer surface of the end of the annular stator 15.
7 with the nut 18 as shown in FIG.
By rotating this jig, the annular stator 15 can be pulled out in the direction of the arrow and unlocked.

As a jig for releasing this lock, as shown in the embodiment shown in FIGS.
In addition, another bolt 20 may be screwed into the head of this bolt 19. That is, by rotating the tip of the bolt 20 while bringing it into contact with the end of the screw 11, the annular stator 15 can be pulled out in the direction of the arrow and unlocked.

Now, in the transmission set in the tooth contact state shown in FIG. However, the deceleration is transmitted to the output shaft 2 via the gear train of the other intermediate gear 8a and the gear train of the intermediate gear 8b. That is, the tooth contact state of both gear trains by the other intermediate gears 8a and 8b during this rotation in the clockwise direction C is as follows.
With a gap c intervening in the direction of rotation, no power is transmitted, and the tooth surfaces on the opposite side simply follow the rotation while remaining in contact.

In contrast, the input shaft 1 is counterclockwise R (reverse direction)
In this case, contrary to the case of normal rotation, the power is decelerated and transmitted to the output shaft 2 via the gear train of the other intermediate gear 8a and the intermediate gear 8b, and the intermediate gears 8c,
It is not transmitted to the output shaft 2 via the gear train 8d. In other words, the intermediate gear 8 during this reverse rotation R
The tooth contact state between the gear train c and the gear train of the intermediate gear 8d is such that a gap c' is interposed between them in the rotation direction, and the tooth surfaces on the opposite side simply keep in contact with each other and rotate in a follow-up manner. It becomes only

In this way, the gear train on the side that does not transmit power follows the rotation while maintaining the contact state, so when switching from the forward direction C to the reverse direction R, or from the reverse direction R to the forward direction C, the moment of switching Then, the gear train that was following in the contact state immediately performs a power transmission action, and the rotation direction is switched with virtually no backlash. Therefore, accurate transmission can be performed without causing rotational delay due to backlash.

Furthermore, in a conventional structure in which the two tooth surfaces are in simultaneous contact and the backlash is zero, a fatal wedge effect occurs due to the meshing of the two tooth surfaces, making power transmission unsmooth. In this device, there is no wedge effect because the gaps c and c', which correspond to backlash, are interposed on the opposite tooth surface.

Further, in the above-mentioned transmission, the intermediate gears 8a,
8b, 8c, and 8d are rotatably supported by the floating center ring 13 via the idlers 14 that generate oil films, so that fluctuations in the eccentric angle due to the oil films of the idlers 14 and the radial angle of the sun gear 5 By allowing variation in direction, various errors in gear machining are absorbed, and power is equally distributed to multiple gear trains, making extremely smooth operation possible.

In the above-described embodiments, an example based on a star gear mechanism has been described, but the present invention may be constructed based on a planetary gear mechanism in which the intermediate gear is a planetary gear. When using a planetary gear mechanism as a base, the intermediate shaft movement adjustment mechanism described above is
A completely similar device can be obtained by installing it on a carrier that supports intermediate gears (planetary gears).

Furthermore, although the above-mentioned embodiments have been exemplified as a speed reduction device, if the output shaft is used as an input shaft and the input shaft is used as an output shaft, it can be applied as a speed increase device.

〔Effect of the invention〕

As described above, according to the control transmission of the present invention, when half of the intermediate gears are used as the power transmission side, the gear train consisting of the remaining half of the intermediate gears can simply be brought into contact with the tooth surfaces to follow the gear train. Therefore, when switching the rotation direction between forward and reverse, the meshing relationship of the gears can be immediately switched to a state where the backlash is substantially equal to zero. Therefore, accurate transmission without rotational delay is possible. In addition, in the device of the present invention, a gap equivalent to backlash is always formed on the tooth surface on the opposite side to the power transmission side, so the wedge action due to the meshing of two tooth surfaces as in the conventional structure does not occur at all. This enables smooth power transmission.

In addition, since the tooth contact state of the intermediate gear is locked by the wedge effect between the tapered shaft and the cut annular stator, an extremely strong fixation is achieved, and a large rotational moment generated on the tapered shaft. The above-mentioned accurate operation can be guaranteed even under large loads.

Further, in the present invention, the strong lock due to such a wedge effect can be easily released by adding a jig using a screw.

In addition, the intermediate gear is not directly supported on the intermediate shaft, but is rotatably supported on the floating intermediate wheel supported on the intermediate shaft via a loose ring that can form an oil film. Various errors in gear machining are absorbed by allowing fluctuations in the eccentric angle due to the free oil film and fluctuations in the radial direction of the sun gear, and it is possible to equalize the power to multiple gear trains. This enables smooth power transmission.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal sectional view of a transmission according to an embodiment of the present invention, Fig. 2 is a principle diagram illustrating the operation of the transmission when Fig. 1 is viewed from the - arrow direction, and Fig. 3 is the same transmission. An enlarged front view showing the intermediate gear part of the device,
FIG. 4 is a perspective view showing the main parts of the intermediate shaft movement adjustment mechanism used in the same device, FIG. 5 is a longitudinal sectional view showing the intermediate gear part according to another embodiment, and FIG. - A view in the direction of the arrows, FIG. 7 is a vertical sectional view showing the situation when the taper shaft of the same part shown in FIG. 5 is unlocked, and FIG. 8 is a vertical sectional view showing the intermediate gear part according to still another embodiment. , FIG. 9 is a longitudinal sectional view showing the situation when the taper shaft of the same portion is unlocked. 1... Input shaft, 2... Output shaft, 3... Casing, 5... Sun gear, 7... Internal gear, 8a, 8
b, 8c, 8d... intermediate gear, 9a, 9b, 9
c, 9d...Intermediate shaft, 10...Tapered shaft, 11...
...Screw, 12...Nut, 13...Idling intermediate ring,
14... Play, 15... Annular stator, 16... Cut, 17, 17'... Screw, 18... Nut (jig), 19, 20... Bolt (jig).

Claims (1)

[Scope of Claims] 1. Consisting of a star gear mechanism or a planetary gear mechanism in which an even number of intermediate gears 8a, 8b, . . . are interposed between a sun gear 5 and an internal gear 7, the intermediate gear 8
a, 8b... are supported on the floating intermediate ring 13 via loose ends capable of generating an oil film, and the floating intermediate ring is pivotally supported on the intermediate shafts 9a, 9b..., and eccentrically connected to the shaft ends of the intermediate shafts. By rotating the fixed tapered shaft 10, the intermediate shafts 9a, 9b... can be adjusted to move clockwise and counterclockwise along a substantially circumferential direction centered on the axis of the sun gear. At the same time, the slotted annular stator 15 can be fixed on the casing 3 or the carrier through a tight fit, and when the sun gear and the internal gear have stopped rotating, the slotted annular stator can be loosened to fix half of the intermediate shafts. clockwise and the other half of the intermediate shafts counterclockwise, the sun gear and internal gear of the half of the intermediate gears are brought into a state of backlash cancellation in the forward rotation direction, and at the same time, the remaining half of the intermediate shafts are The gear train of the sun gear and the internal gear of half of the intermediate gears is brought into a state of backlash elimination in the reverse direction, and in this state, the slotted annular stator is tightly fitted to fix the tapered shaft. Device. 2. Provide screws on the outer or inner surface of the annular stator,
The control transmission according to claim 1, wherein the tight fitting of the annular stator can be released by a jig screwed onto the screw.