JPH0420099B2 - - Google Patents

Description

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

[Prior art]

Control equipment such as industrial robots is operated so that the rotation direction of a transmission shaft changes from forward to reverse at any time.
Gears are indispensable in transmission devices installed in such control equipment, but these gears are always equipped with a backlash. Therefore, when switching the rotation direction between forward and reverse, a rotation delay occurs by the amount of this backlash, resulting in a loss of power. The problem of inaccurate communication has been pointed out.

Conventionally, as a method to eliminate the rotation delay equivalent to the backlash, a mechanism has been used in which gears are stacked double and the phase is shifted by the backlash. However, fixing two gears to a shaft with a phase shift corresponding to the minute backlash of irregularities that inevitably occur during machining is not only extremely difficult to manufacture from the viewpoint of indexing accuracy during machining. Since the meshing of the gears assembled in this manner is a so-called two-tooth meshing, there is a problem in that power transmission cannot be carried out smoothly.

[Problem to be solved by the invention]

The purpose of the present invention is to create a combination of helical gears and spur gears that eliminates any rotation delay equivalent to backlash when switching the rotation direction between forward and reverse directions, and enables smooth power transmission. The object of the present invention is to provide a control transmission device that performs the following steps.

[Means to solve the problem]

A control transmission of the present invention that achieves the above object constitutes a gear train by simultaneously meshing two gears with a gear on an input shaft, and includes two intermediate shafts fixed to the two gears, as well as two intermediate shafts fixed to the two gears. Different gears are fixed to each end, and these two different gears are simultaneously meshed with the gear on the output shaft to form another gear train, one of the gear trains is a helical gear, and the other is a helical gear. A spur gear is used, at least one of the intermediate shafts is movable in the axial direction, and a screw mechanism for moving the intermediate shaft in the axial direction is provided at the end of the shaft, and the screw mechanism moves the intermediate shaft in the axial direction. by moving the gears fixed to both ends of one of the intermediate shafts so that the meshing of the gears is 0 in the forward rotation direction, and the meshing of the gears fixed to the other end of the intermediate shaft is 0 in the reverse direction. The present invention is characterized in that the power is alternately switched and transmitted between the two intermediate shafts when switching between forward and reverse rotations.

〔Example〕

FIGS. 1 and 2 show an example in which the control transmission of the present invention is used as a reduction gear.

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 a bearing 5 supported on a cover plate 3a of the casing 3 and a bearing 6 supported on a stay 4 fixed to the cover plate 3a, and the output shaft 2 is supported by a bearing 5 supported on a cover plate 3a of the casing 3. It is rotatably supported by bearings 7, 7 provided inside the boss portion 3b. A gear 8 is fixed to the input shaft 1, and an internal gear 9 is fixed to the output shaft 2. In this embodiment, the gear 8 has external teeth and the gear 9 has internal teeth. However, the invention is not limited to this, and both the gear 8 and the gear 9 may have internal teeth or external teeth. good.

Reference numerals 10 and 10' designate two intermediate shafts, each of which has both ends rotatably supported by the cover plate 3a of the casing 3 and the stay 4 via bearings 11, 12; 11', 12'. It is possible to move freely in any direction. Gears 13, 14; 13', 14' are fixed to both ends of these intermediate shafts 10, 10', respectively.
Of these, the gears 13 and 13' are simultaneously meshed with the gear 8 of the input shaft 1 to constitute a gear example, and the gears 14 and 1
4' meshes with the gear 9 of the output shaft 2 at the same time to constitute another gear train. One of these gear trains is a helical gear, while the other is a spur gear. In this embodiment, as shown in FIG. The row side is a helical gear, gears 9, 14, 1
The gear train side 4' is composed of spur gears.

In addition, one intermediate shaft 1 that is movable in the axial direction
A screw mechanism 16 composed of a screw 15 screwed into the cover plate 3a is provided at the end of the screw mechanism 16, and by screwing the screw 15 of the screw mechanism 16, the intermediate shaft 10 is moved in the axial direction. It is now possible to do so. The screw mechanism 16 includes a screw 15 and an intermediate shaft 10, as in another embodiment shown in FIGS.
A mechanism may be adopted in which a spring 18 such as a disc spring is inserted between the shaft end of the shaft and the thrust bearing 17. The spring 18 may be a coil spring, or may be replaced with an elastic body such as rubber.

Before or after the above-mentioned transmission is incorporated into the power transmission system of the control device, the following backlash elimination operation is performed using the above-mentioned screw mechanism 16 before it is put into operation.

That is, to explain with reference to FIGS. 5 to 7 shown as principle diagrams, first, the input shaft 1 is clamped and locked, and then the screw 15 is turned to the left as shown by arrow A in FIG. Advance the intermediate shaft 1
0 in the axial direction. Then, gears 8, 13
is a helical gear, its helical direction (inclination direction) is the direction shown in the figure, and the gear 8 is in a locked state, so the gear 13 moves as shown by arrow A due to the axial movement of the intermediate shaft 10. As a result, gears 14, 9, 14', and 13' also rotate sequentially in the direction of arrow A, and stop when the tooth surface of the last gear 13' contacts the tooth surface of gear 8, which is in the locked state. do. Gears 8, 13, 13' when stopped
The state of contact between the teeth of the gear train and the gear train of gears 9, 14, and 14' are as shown in FIGS. 6 and 7, respectively.

When the tooth contact state of each gear is set to the state shown in FIGS. 6 and 7, the clamp on the input shaft 1 is released to make it ready for operation. Assuming that the input shaft 1 alternately switches between forward rotation F and reverse rotation R during this operation, when rotating in the forward rotation F direction,
Power is transmitted to the output shaft 2 through the meshing of the gears 8, 13 and the gears 14, 9, and is not transmitted to the output shaft 2 through the meshing of the gears 8, 13' and the gears 14', 9. In other words, the tooth contact relationship between gears 8 and 13' during forward rotation F is such that there is a gap c' in the rotation direction, and no power is transmitted, and the tooth surface on the opposite side is simply The gear 13' simply rotates following the gear 8 in a contact state.

On the other hand, when the input shaft 1 is in the reverse rotation R direction, the power is transmitted to the output shaft 2 through the meshing of the gears 8, 13' and the gears 14', 9, contrary to the above-mentioned normal rotation. , 13 and the gears 14, 9, the signal is not transmitted to the output shaft 2. That is, the tooth contact relationship between gears 8 and 13 during this reverse rotation R is such that a gap c is interposed in the direction of rotation, and the tooth surfaces on the opposite side are simply brought into contact, and gear 1
3 only rotates following the gear 8.

Since the gear train on the non-power transmitting side simply maintains a contact state and follows the rotation, it changes from forward rotation F to reverse rotation R, and from reverse rotation R to forward rotation F.
At the moment of the switch, the tooth surface side that was following in the contact state immediately performs a power transmission action, and in fact, the rotation direction is switched without any rotation delay. Therefore, with this control transmission, the amount of rotational transmission does not become inaccurate by the amount of backlash.

Furthermore, when power is transmitted from the input shaft 1 to the output shaft 2 as described above, the helical gears 8, 13, 1
When the helical direction (inclination direction) of 3' is the direction shown in Fig. 5, the thrusts T and T' generated on the intermediate shafts 10 and 10' are always in the direction shown by the arrow, regardless of whether it is forward or reverse. , FIG. 6, and FIG. 7 are always maintained.

In addition, when using an elastic material such as a spring as the screw mechanism 16 as in the embodiment shown in FIGS. 3 and 4, by appropriately selecting the elastic force, it is possible to Even if the error is large, generation of abnormal force can be avoided. Also, according to this screw mechanism, when performing the first backlash erase operation, the screw 1
By adjusting the strength of the screw torque in step 5,
The smoothness of rotation can also be adjusted.

In the above embodiment, since the gears 8, 13, and 13' of the gear train on the input shaft 1 side are helical gears, the input shaft 1 is clamped when performing the backlash elimination operation, but the gears on the output shaft 2 side are clamped. When gears 9, 14, 14' in the row are helical gears,
The output shaft 2 is clamped to perform backlash elimination operation.

Furthermore, although the above-mentioned embodiment has been exemplified as a speed reduction device, if the output shaft 2 is used as an input shaft and the input shaft 1 is used as an output shaft, it becomes possible to apply the device as a speed increase device.

〔Effect of the invention〕

As described above, in the present invention, two gears are simultaneously meshed with a gear on an input shaft to form a gear train, and separate gears are respectively attached to the other ends of two intermediate shafts fixed to the two gears. is fixed, these two other gears are simultaneously meshed with the gear on the output shaft to form another gear train, one of the two gear trains is a helical gear, the other is a spur gear, and the At least one of the intermediate shafts is movable in the axial direction, and a screw mechanism is provided at the end of the shaft, and the intermediate shaft is moved in the axial direction via the screw mechanism and fixed to both ends of one of the intermediate shafts. The meshing of the gears is set to 0 in the forward rotation direction, and the meshing of the gears fixed at the other end is set to 0 in the reverse direction, so that when switching between forward and reverse rotations, the power is set to 0 between the two. Since the configuration is such that transmission is alternately switched between the shafts, when the meshing of the gears on one intermediate shaft is set to the power transmission side, the meshing of the gears on the other intermediate shaft is simply set so that the tooth surfaces on the opposite side are in contact. You can just let it follow you.
Therefore, when the rotational direction of the power is switched to normal rotation, it can be switched without any rotational delay equivalent to backlash occurring. Moreover, since the above gear meshes with the tooth surface on the opposite side of the rotation direction with a bumpy clump, it does not rotate unevenly as would be the case with two tooth surfaces meshing.
Extremely smooth power transmission is possible.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of a transmission according to an embodiment of the present invention, FIG. 2 is a view taken along the - arrow in FIG. 1, FIG. 3 is a longitudinal cross-sectional view showing another embodiment of the screw mechanism, and FIG. is a view in the direction of the − arrow in FIG. 3, FIG. 5 is a principle diagram for explaining the operation of the transmission, FIG. 6 is a view in the direction of the − arrow in FIG. 5, and FIG. 7 is a view in the direction of the − arrow in FIG. This is a perspective view. 1...Input shaft, 2...Output shaft, 10, 10'...
...Intermediate shaft, 8, 9, 13, 13', 14, 14'...
...Gear, 15...Screw, 16...Screw mechanism, 17
...Thrust receiver, 18...Spring.

Claims (1)

[Scope of Claims] 1 A gear train is formed by simultaneously meshing two gears with the gear of the input shaft, and different gears are respectively attached to the other ends of two intermediate shafts fixed to the two gears. fixed, and these two other gears are simultaneously meshed with the gear on the output shaft to form another gear train, one of the two gear trains is a helical gear, the other is a spur gear, and both the gear trains are fixed. At least one of the intermediate shafts is made freely movable in the axial direction, and a screw mechanism for moving the intermediate shaft in the axial direction is provided at the end of the shaft, and the screw mechanism moves the intermediate shaft in the axial direction. The meshing of the gears fixed to one end of the shaft is set to 0 in the forward direction, and the meshing of the gears fixed to the other end is set to 0 in the reverse direction. A control transmission device configured to alternately switch and transmit power between the two intermediate shafts when the rotation is switched. 2. The control transmission according to claim 1, wherein the screw mechanism is configured by a screw being provided oppositely to the shaft end of the intermediate shaft via a spring or an elastic body.