JPH0310474B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Technical Field The present invention relates to a rotation transmission device for an industrial robot in which a rotating member serving as a wrist member is disposed at the tip of an arm member.

Prior Art Generally, in this type of industrial robot,
In order to reduce the weight and size of the distal end of the arm member, the drive source for the rotating member, that is, the wrist member, is located at a distance from the distal end of the arm member, and is driven via an appropriate rotation transmission device. Force is being transmitted to the wrist member side.

By the way, as a rotation transmission device, a chain,
Timing belts, chain sprockets, pulleys, and various bevel gears are often used, but when assembling this rotation transmission device, play inevitably occurs due to various factors. Conventionally, rotation transmission devices equipped with various correction mechanisms have been proposed in order to completely eliminate this backlash, but a practical rotation transmission device for industrial robots that can be made smaller and lighter has not yet been realized.

OBJECTS OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide a practical rotation transmission device for an industrial robot that can be made smaller and lighter.

Embodiments The present invention will now be described in detail with reference to illustrated embodiments. Now, when talking about multi-joint arm type industrial robots, in Figures 1 to 3, 1
3 and 4 are horizontally rotatably supported frames 3 and 4 with respect to the fixed member 2 by a drive source (not shown).
The lower arm and the link lever are rotatably supported on the underframe 1, the rear arm 5 is rotatably supported on the link lever 4, and the lower arm 3 and the rear arm 5 are rotatably supported. The supported upper arm 6, lower arm 3, link lever 4, and rear arm 5 form a parallel link mechanism. Reference numeral 8 denotes a rotating part disposed at the distal end of the upper arm 6. In the illustrated case, the wrist part 9 is constituted by the rotating frame 7 that rotates on a plane perpendicular to the upper arm 6 and the rotating part 8. 11 to 13 are first to third rotation transmission members, for example, chain sprockets, and these first to third chain sprockets 11, 12, 13 are connected to appropriate bearings 14 to 1.
The chain sprockets 11, 12, and 13 are configured to be rotatable coaxially through the upper arm 6 and independently of the upper arm 6, and the first chain sprocket 11 is integrally formed with the rotating frame 7. It is fastened to. 21 and 22 are first and second bevel gears that rotate integrally with the first and second chain sprockets 12 and 13, respectively, and the first bevel gear 21 is faster than the second bevel gear 22. It is also formed to have a large diameter. In addition, as shown in the figure, the adjustment nuts 23, 2
4, 25 and disc springs 26, 27, 28 are advantageous because, for example, the first and second bevel gears 21, 22 can be set at appropriate positions in the X direction. That is, the adjusting nut 23 is
When the first bevel gear 21 is screwed in the _X1 direction, the shaft 12 rotates integrally with the second sprocket 12.
1 in the X ₁ direction. Similarly, due to the rotation of the adjusting nut 24, the second bevel gear 22 is displaced on the shaft 131 of the third sprocket 13 in the X direction. 31 is a cylindrical shaft rotatable with respect to the upper arm 6;
In the illustrated case, the cylindrical shaft 31 is rotatably supported with respect to the rotating frame 7 via bearings 32 and 33 arranged on the Z ₁ side and the Z ₂ side. Note that the bearing 32 is supported integrally with the cylindrical shaft 31 and is slidable in the longitudinal direction with respect to the rotating frame 7, and the cylindrical shaft 31 and the bearing 33 are mutually slidable in the longitudinal direction. It is composed of A third bevel gear 34 meshes with the first bevel gear 21, and in the illustrated case, it is integrally disposed at the end of the cylindrical shaft 31 in the _Z1 direction. 35 is a fourth bevel gear that meshes with the second bevel gear 22; 36 is a transmission shaft rotatably inserted into the cylindrical shaft 31;
A fourth bevel gear 35 is integrally disposed at the end of the gear 6 in the _Z1 direction. Reference numeral 37 denotes a rotating member that is inserted into the outer periphery of the end of the cylindrical shaft 31 in the Z ₂ direction and rotates integrally with the cylindrical shaft 31.
and are configured to be slidable relative to each other in the longitudinal direction by, for example, sliding key fitting. 38 is the cylindrical shaft 3
1, a first adjustment tool screwed onto the outer periphery of the end in the Z ₂ direction, 39 a second adjustment tool screwed onto the inner periphery of the end in the Z ₂ direction of the cylindrical shaft 31, 40 a transmission A rotation transmission member, for example a bevel gear, is disposed at the end of the shaft 36 in the Z ₂ direction so as to be slidable in the longitudinal direction, and 41 is a Z ₂ of the transmission shaft 36.
a third adjuster screwed onto the end of the direction, 42,4;
3 and 44 are bearings, and the bearing 42 is supported integrally with the transmission shaft 36 and is slidable in the longitudinal direction with respect to the cylindrical shaft 31, and the bearings 43 and 44 and the transmission shaft are mutually supported in the longitudinal direction. It is configured to be able to slide freely. 45
46 is a first spring member that separates the cylindrical shaft 31 and the rotating member 37 from each other in the longitudinal direction via a bearing 33, and 46 similarly connects the transmission shaft 36 and a second adjustment member via a bearing 44. 39 is a second spring member that separates them from each other in the longitudinal direction. Note that the first and second spring members 45 and 46 are disc springs or compression springs. 47 is a rotation transmitting member that meshes with the rotation transmitting member 40, and 48 is an output shaft.

In the above configuration, it is assumed that each part is assembled as shown in FIG. However, it is assumed that the rotation transmission member 47 and the output shaft 48 have not been assembled.

Now, assume that the first bevel gear 21 is disposed at a position in the _X1 direction from a predetermined position due to manufacturing errors and assembly errors of parts.

In this case, when the first adjusting tool 38 is rotated so that the first adjusting tool 38 spirally advances in the Z ₂ direction with respect to the cylindrical shaft 31, the cylindrical shaft 31 is moved in the Z ₁ direction by the first spring member 45. direction, and the first adjustment tool 38 is positioned in a state where it is in contact with the rotating member 37. By this adjustment, the third bevel gear 34 supported at the end of the cylindrical shaft 31 in the _Z1 direction and the first bevel gear 21 mesh with each other. In this case, the first and third bevel gears 21 and 34 mesh at positions displaced in the X ₁ direction and the Z ₁ direction with respect to the predetermined position, respectively, so that the effective meshing surfaces of the bevel gears are Although it decreases,
Of course, since this is taken into consideration in the design, there will be no problem in terms of strength.

Before and after the above adjustment work, the second adjustment tool 39
When it is spirally moved in the _Z1 direction, 35, 36, 39 to 44 and 46 are integrally displaced in the _Z1 direction. In this way, the rotation transmission member 47 and the output shaft 48 are attached with the rotation transmission member 40 set at a position slightly in the _Z1 direction from the predetermined position.
Thereafter, the second adjustment tool 39 is screwed in the _Z2 direction to adjust the position of the rotation transmission member 40 in the _Z2 direction.
Next, by appropriately rotating the third adjuster 41, the position of the fourth bevel gear 35 is arbitrarily adjusted in the _Z1 direction or the _Z2 direction.

In this way, the third and fourth bevel gears 3
After adjusting the positions of the rotation transmitting member 4, 4 and 35 separately, a desired driving force is transmitted to the wrist portion 9 by an appropriate drive mechanism (not shown).

In addition, since the first to third adjustment tools are disposed on the same end side of the coaxial transmission shaft and the cylindrical shaft, the third umbrella can be adjusted by the first to third adjustment tools. Since the gear, the fourth bevel gear, and the rotation transmission member are configured so that their positions can be adjusted independently with respect to the arm member, the adjustment work of the bevel gear and rotation transmission member is easy, and the driving force is transmitted without play. be done.

Furthermore, since the third bevel gear and the fourth bevel gear are each attached to the arm member via a spring member, overload rotational force, impact rotational force, etc.
It has a buffering effect against so-called impact loads, so there is no risk of damaging the rotation transmission parts.

Of course, any driving force is transmitted to the wrist portion 9, but in this case, the swivel base 1, lower arm 3, and upper arm 6 are operated as appropriate.

In the above case, for example, if the output shaft 48 is provided with a support member that supports an operating element such as an assembly tool, a paint spray gun, or a welding torch, the rotation frame 7, the rotation member 8, and the support member can support the wrist. 9, the operating elements can be positioned in any desired state. Of course, the rotation transmission member 4
The zero driving force can be applied to linear movement of the operating element or used to open and close the handling member.

In the above embodiment, the bearing 33 is the rotating member 37
Although the bearing 33 is disposed at the end of the rotating member 37, it is also possible to dispose the bearing 33 on the outer circumference of the rotating member 37. In this case, the first spring member 45 will come into direct contact with the rotating member 37. In addition, the first adjustment tool 38
It can also be screwed onto the rotating member 37 so that it can be screwed in the Z direction. In this case, a protrusion that can come into contact with the first adjuster 38 is provided on the cylindrical shaft 31 at a position further in the Z ₂ direction than the first adjuster 38 . Furthermore, as the rotation transmission member 40, an appropriate member such as a spur gear, a chain sprocket, or a pulley can be selected. Of course, it is advantageous to provide the swing frame 7 as described above because the degree of freedom of the wrist portion is large, but the swing frame 7 can be fixed to the arm member 6 in spite of this. Further, the cylindrical shaft 31 and the third bevel gear 34 may be formed separately, or the fourth bevel gear 35 and the transmission shaft 36 may be formed integrally.

Note that the present invention can be applied to any suitable industrial robot such as a polar coordinate system, a cylindrical coordinate system, or an orthogonal coordinate system.

Effects of the Invention As described in detail in the above embodiment, the present invention includes at least two bevel gears having different diameters coaxially disposed at the distal end of the arm member, and a third bevel gear meshing with these two bevel gears. A fourth bevel gear is disposed at the ends of the cylindrical shaft and the transmission shaft, respectively, and the transmission shaft and the cylindrical shaft are coaxially arranged and rotatable with respect to the arm member, respectively, and the transmission shaft is coaxial. Since the first to third adjustment tools are arranged on the same end side of the shaft and the cylindrical shaft, the industrial robot can be made smaller and lighter, and the first to third adjustment tools are Coupled with the fact that they are disposed on the same end side of the coaxial transmission shaft and cylindrical shaft, the third bevel gear, the fourth bevel gear, and the rotation transmission member are controlled by the first to third adjustment tools. are configured to be able to adjust their positions separately with respect to the arm member, so the adjustment work of the bevel gear and the rotation transmission member is easy, the driving force is transmitted without play, and the third bevel gear and the rotation transmission member are Since the bevel gears 4 are each attached to the arm member via a spring member, they have a buffering effect against so-called impact loads such as overload rotational force and impact rotational force, and therefore the rotation transmission parts It is possible to realize an extremely practical industrial rotation transmission device without the risk of damaging the rotor.

[Brief explanation of drawings]

Fig. 1 is a left side view showing an industrial robot equipped with a rotation transmission device according to the present invention, Fig. 2 is a sectional view taken along the - line in Fig. 1, and Fig. 3 is a sectional view taken along the - line in Fig. 2. . 6... Upper arm, 7... Swivel frame, 8... Rotating part, 9... Wrist part, 21... Large diameter bevel gear, 22... Small diameter bevel gear,
31...Cylindrical shaft, 34...Third bevel gear, 35...Fourth
bevel gear, 36...transmission shaft, 37...rotating member, 38
...first adjustment tool, 39...second adjustment tool, 40...rotation transmission member, 41...third adjustment tool, 45...first spring member, 46...second spring member.

Claims (1)

[Claims] 1 At least two bevel gears having different diameters are coaxially disposed at the tip of the arm member, and a third bevel gear that meshes with the large diameter bevel gear is supported at the end of a freely rotatable cylindrical shaft. , a rotating member is disposed at the other end of the cylindrical shaft,
A fourth bevel gear that meshes with the small diameter bevel gear is fixed to one end of a transmission shaft coaxially and rotatably inserted into the cylindrical shaft, and a rotation transmission member is disposed at the other end of the transmission shaft. In the rotation transmission device for an industrial robot, the cylindrical shaft and the rotating member are configured to be movable in a longitudinal direction, and the first and second bevel gears are rotated independently and suitably. A first spring member is provided that separates the cylindrical shaft and the rotating member from each other in the longitudinal direction, and is in relative contact with the cylindrical shaft and the rotating member at an end position of the cylindrical shaft. A first adjusting tool whose position can be freely set in the longitudinal axis direction is disposed, a second adjusting tool whose position can be freely set in the longitudinal axis direction is arranged on the inner circumference of the end of the cylindrical shaft, and A second spring member is provided to separate the adjustment tool and the transmission shaft from each other in the longitudinal direction, and the rotation transmission member that abuts the second adjustment tool via a rotation bearing is aligned with the transmission shaft in the longitudinal direction. A rotation transmission device for an industrial robot, which is provided with a third adjusting tool whose position can be freely set in any direction.