JPH06245446A - Two-shaft integral-type motor - Google Patents

Abstract

PURPOSE:To decrease the number of parts and to make any special processing and adjustment work useless by containing two motor mechanisms with mutual rotor shafts forming the output parts of a double shaft in one motor case and by fixing stators in two axial places into one motor. CONSTITUTION:Respective first and second motor mechanisms 2, 3 having respective first and second rotor shafts 7, 9 forming the output parts 7a, 9a of a double shaft are contained in one motor case 1. Then, respective first and second bearing housings 12, 14 for holding respective first and second bearings 11, 13 for fixing respective first and second stators 4, 5 in two axial places and for pivoting the first and second rotor shafts 7, 9 in both thrust and radial directions are arranged at respective ends of the motor case 1. Further, first and second detecting members 31, 32 for detecting the rotational state of the first and second rotor shafts 7, 9 are provided outside the first and second bearings 11, 13. respectively.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a two-axis integrated motor, and more particularly, a two-axis output unit for performing different operations with one motor so as to form a double axis on the same axis. The present invention relates to an integrated motor.

[0002]

2. Description of the Related Art For example, in order to operate a first axis and a second axis of a horizontal direct drive robot, a direct drive motor having axes that move differently is required.

FIG. 2 shows one specific example. This is the National Technical Rep
ort Vol. 36 No. 1 (Feb. 1990)
It is a horizontal direct drive robot announced on pages 10 to 15.

The outline will be described. The second arm b is connected to the tip of the first arm a of the robot body with a joint as shown in the drawing. The first arm a can be driven directly by the first direct drive motor c, and the second arm b can be driven individually by the second direct drive motor d via the pulleys e, f and the steel belt g. ing.

As shown in FIG. 3, the first and second direct drive motors c and d are integrally formed by abutting and joining the first and second motor cases h and i in the axial direction. At the same time, by inserting one end side of the second rotor shaft k included in the second direct drive motor d into the hollow hole of the first rotor shaft j included in the first direct drive motor c, a double shaft structure is obtained. The output parts 1 and m are formed so that the first and second arms a and b can be individually driven as described above.

By the way, in order to control the operation of the first and second arms a and b of the robot, the first and second detections of the rotation amounts of the first and second rotor shafts j and k are performed. Encoder mechanisms n and o are required.

Therefore, the first and second direct drive motors c and d are connected to the first and second motor cases h and i, respectively.
Fixed to the first and second stators p and q, and a combination portion with the first and second rotors r and s paired therewith, and the first and second rotor shafts j and k. To the first and second motor cases h and i, the first and second bearings t and u.
And the first and second encoder mechanisms n and o have a common arrangement structure in which they are arranged in the same order.

The first and second bearings t and u are directly supported by the first and second motor cases h and i to support the first and second rotor shafts j and k. is doing.

[0009]

However, as in the prior art, the first and second separate direct drive motors c and d housed in the first and second separate motor cases h and i are used in combination. Then, the number of parts is large, and in order to properly combine the first and second rotor shafts j and k of the first and second separate direct drive motors c and d without shaft tilt or shaft runout, Because special processing and adjustment are required,
It will be expensive. Moreover, the adjustment of the shaft tilt and the shake of the shaft is sometimes insufficient, and an error may occur in the detection of the rotational state of the first and second rotor shafts j and k by the first and second encoder mechanisms n and o. It may cause a malfunction.

Further, the first and second bearings t and u are
Since the second rotor shafts j and k are directly supported by the first and second motor cases h and i, the rigidity of the first and second motor cases h and i is first and second. In the case where it is desired to make the first and second motor cases h and i made of aluminum for the purpose of weight reduction and heat dissipation, the shafts of the rotor shafts j and k of No. 2 are greatly affected, and the shafts are not sufficiently rigid. Falling is a problem, so it's difficult to achieve. Further, because of the common arrangement structure of the first and second direct drive motors c and d, the first and second bearings t and u are the axes of the first and second motor cases h and i. The first and second rotor shafts j and k are borne at a substantially intermediate position in the direction, and are largely separated from the output ends where the output parts l and m are connected to the load. The output parts 1 and m lack stability in rotation. Therefore, it is necessary to separately provide bearings v and w for suppressing this,
The number of parts and the number of assembly steps are further increased, which causes a cost increase.

Moreover, since the encoder mechanisms n and o are in a recessed position such as between the first and second direct drive motors c and d and inside the bearings v and w, it is difficult to adjust or replace them. And the maintainability is poor.

[0012]

In order to achieve the above-mentioned object, the two-shaft integrated motor of the present invention has a second rotor shaft on the same axis as one end side of the first rotor shaft. Each of the first and second motor mechanisms that are inserted into the hollow holes of the double shafts and serve as the output portion of the double shaft is housed in one motor case, and the first and second motor mechanisms are respectively provided at two locations in the axial direction of the motor case. A first bearing housing, which holds the first and second stators of the motor mechanism and holds a first bearing for bearing the first rotor shaft in both thrust and radial directions, is provided at one end of the motor case. A second bearing housing that supports and holds a second bearing that bears the second rotor shaft in both thrust and radial directions is supported at the other end of the motor case, and the first bearing is provided outside the first bearing. First detection for detecting the rotation state of the rotor shaft The timber, also outside the second bearing second
Second detection members for detecting the rotation state of the rotor shaft are provided.

[0013]

In the above-described structure of the two-shaft integrated motor of the present invention, the first and second motor mechanisms whose rotor shafts form the double shaft output portion are housed in one motor case. Since these stators are fixed at two locations in the axial direction to form one motor, the number of parts can be reduced compared to the conventional combination of two motors, and the two motor cases are butted. It is possible to eliminate the need for special processing and adjustment work for joining and without joining the rotor shafts of the two motors to each other without tilting or wobbling of the shafts.

Further, since the first and second rotor shafts having the double shaft output portion are borne by the bearings provided at one end and the other end of the one motor case, respectively, Since both ends of each of the second rotor shafts, in particular, the ends of the output part are also supported stably, it is possible to omit adding a special bearing structure to the output part, and the bearing is a single This is done through the bearing housings provided at each end of the motor case, so that the rigidity of the motor case can be prevented from affecting the support accuracy of the first and second rotor shafts.

Further, the first and second detection members for detecting the rotational states of the first and second rotor shafts are the first and second detection members.
It is located outside each of the bearings and can be easily adjusted or replaced from the end of the motor case.

It is preferable that the motor case is made of a metal material having a high heat dissipation property, and the housings of the first and second bearings are made of a material having higher rigidity than the material of the motor case.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A two-axis integrated motor as an embodiment to which the present invention shown in FIG. 1 is applied will be described below.

As shown in FIG. 1, one motor case 1
The first and second motor mechanisms 2 and 3 are housed therein. The first and second motor mechanisms 2 and 3 respectively have first and second stators 4 and 5 respectively fixed to two positions in the motor case 1 in the axial direction.

As a result, the first stator 5 is paired with the first rotor shaft 7 having the first rotor 6 forming the first motor mechanism 2 and the second rotor 5. The second rotor shaft 9 having the second rotor 8 forming the second motor mechanism 3 and the second rotor shaft 9 are located side by side on the same axis.

One end side of the first rotor shaft 7 is inserted through the hollow hole of the second rotor shaft 9 to form double shaft output portions 7a and 9a.

A bearing housing 12 holding a first bearing 11 for bearing the first rotor shaft 7 in both thrust and radial directions, and a second bearing for bearing the second rotor shaft 9 in both thrust and radial directions. A second bearing housing 14 holding 13 is formed separately from the motor case 1.

While the motor case 1 is made of aluminum which is lightweight and has good heat dissipation, the first and second bearing housings 12 and 14 are made of an iron material having a rigidity higher than that of the aluminum.
Are formed. First and second bearing housings 1
Reference numerals 2 and 14 are applied to both end portions of the motor case 1 from the outside, and are attached and supported by bolts 16 in a positioning state having a cylindrical fitting portion 15 in a part thereof.

Cross roller bearings are used for the first and second bearings 11 and 13, and the first bearing 11 is the first bearing.
Of the inner and outer rings on the first rotor shaft 7 side and the first bearing housing by means of the bearing retainer 22 attached to the rotor shaft 7 of the above with the bolt 21 and the bearing retainer 23 attached to the first bearing housing 12 with the bolt 21. It is fixed to each 12 side.

The second bearing 13 is mounted on the second rotor shaft 9 with bolts 21 and serves as a bearing retainer output end shaft 24.
The inner and outer races are fixed to the second rotor shaft 9 side and the second bearing housing 14 side, respectively, by a bearing retainer 25 attached to the second bearing housing 14 with bolts 21.

The type of bearing is not limited to the cross roller bearing. For example, a radial bearing and a thrust bearing can be used together, and the fixing structure can be variously changed depending on what kind of thing is adopted.

The first and second bearings 11, 13 as described above
Due to the bearing structure of the above, the two rotor shafts 7 and 9 forming the double shaft are connected to one motor case 1 to connect the two motor cases, and special processing is required for this connection accuracy. It is possible to prevent the shaft from tilting, shake the shaft, and the like, without bearing, and to stably support and support the shaft at both ends.

In particular, the second bearing 13 includes the output parts 7a and 9a.
Since the output portions 7a and 9a are located near the output end, stability is not lost even when the output portions 7a and 9a are connected to and drive a load, and another bearing is provided to stabilize the output portions 7a and 9a. No such thing is necessary.

Further, the motor case 1 is made of aluminum having low rigidity in order to reduce the weight and improve the heat dissipation, but the first and second bearing housings 12 and 14 are used.
Is higher in rigidity than the motor case 1, so even if the rigidity of the motor case 1 is low, the
The second rotor shafts 7 and 9 can be supported with high precision without shaft tilting, and sufficient precision can be guaranteed.

A first encoder mechanism 31 for detecting the rotation state of the first rotor shaft 7 is provided outside the first bearing 11.
Further, outside the second bearing 13, second encoder mechanisms 32 for detecting the rotation state of the second rotor shaft 9 are provided, respectively.

The encoder disk 33 constituting the first encoder mechanism 31 is attached to the outer periphery of the portion of the first rotor shaft 7 that slightly projects outward from the bearing 11, and the photocoupler 34 is attached to the outside of the first bearing housing 12. It is attached to a lid 35 that closes the end opening.

An encoder disk 36 constituting the second encoder mechanism 32 is attached to the outer circumference of the output end shaft 24 also serving as a bearing retainer attached to the second rotor shaft 9, and a photocoupler 37 of the second bearing housing 14. A cover 38 that is attached to the outer end portion and that covers the second encoder mechanism 32 is attached to the outer end portion of the second bearing housing 14.

As described above, the first and second encoder mechanisms 31 and 32 can detect the rotating states of the first and second rotor shafts 7 and 9 without being exposed to the outside, respectively, and can detect dust and the like. There is no external influence.

The bearing accuracy of the first and second rotor shafts 7 and 9 is good, and there is no shaft tilt or shaft runout.
The rotation states of the second rotor shafts 7 and 9 can be detected with high accuracy.

Therefore, the first and second rotor shafts 7,
When the first axis and the second axis of the horizontal direct drive robot are connected to the output units 7a and 9a of 9 as external loads and the robot is driven, the position can be controlled with high accuracy.

However, each of the first and second encoder mechanisms 3
The specific mounting structure of 1, 32 can be variously modified. In short, the first and second encoder mechanisms 31,
32 is a first provided at the end of the motor case 1,
By being located further outside the second bearings 11 and 13 and being located on the outermost side of the two-shaft integrated motor, in this embodiment, only the lid 35 or the cover 38 is removed, and adjustment or replacement is performed from the outside. Can be performed and maintenance becomes easy.

Various kinds of detecting members for detecting the rotational states of the first and second rotor shafts 7 and 9 can be adopted, and the present invention is not limited to the above embodiment.

[0037]

According to the two-shaft integrated motor of the present invention, the two first and second motor mechanisms whose rotor shafts form the output part of the double shaft are housed in one motor case. These stators are fixed at two locations in the axial direction to form one motor, and the number of parts required is smaller than when combining two motors as in the past, and two motor cases are used for two motors. Since no special processing or adjustment work is required for butt-joining without tilting or swinging of the rotor shaft, it is easy to manufacture and inexpensive.

Further, the first and second rotor shafts having the double shaft output portion are borne by the bearings provided at one end and the other end of one motor case, and these bearings are the first. Since it is possible to stably support both end portions of the second rotor shaft, particularly the end portion of the output portion and to add another bearing structure to the output portion, it is possible to reduce the number of parts and the number of assembling steps in this aspect as well. It can be reduced and the cost can be reduced.

Further, each of the first and second bearings is held in a bearing housing supported at each end of one motor case to support the first and second rotor shafts, and the rigidity of the motor case is Since the bearing accuracy is prevented from being affected, the bearing accuracy of each of the first and second rotor shafts can be sufficiently maintained even if the motor case is made lightweight and has low rigidity such as aluminum material for heat dissipation. It can be ensured and the detection accuracy of the rotation state by the detection member can be prevented from deteriorating.

The first and second detection members for detecting the rotational states of the first and second rotor shafts are provided outside the first and second bearings held at the end of the motor case. In this case, since it is easy to adjust or replace the end of the motor case, the maintainability is enhanced.

If the motor case is made of a metal material having a high heat radiation property and the housings of the first and second bearings are made of a material having a higher rigidity than the material of the motor case, the heat radiation property of the motor case will make the motor durable. The high rigidity of the bearing housing can sufficiently prevent the low rigidity due to the heat radiation material of the motor case from affecting the bearing accuracy.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional view of a two-axis integrated motor as an embodiment to which the present invention is applied.

FIG. 2 is a schematic configuration diagram showing a conventional horizontal direct drive robot.

FIG. 3 is a vertical cross-sectional view showing a conventional drive motor used to drive the robot of FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Motor case 2 1st motor mechanism 3 2nd motor mechanism 4 1st stator 5 2nd stator 6 1st rotor 7 1st rotor shaft 8 2nd rotor 9 2nd rotor shaft 7a, 9a Output part 11 1st bearing 12 1st bearing housing 13 2nd bearing 14 2nd bearing housing 31 1st encoder mechanism 32 2nd encoder mechanism

Claims (1)

[Claims] 1. A first motor mechanism and a second motor mechanism, wherein one end of a first rotor shaft is inserted into a hollow hole of a second rotor shaft on the same axis as the first rotor shaft to form a double shaft output portion. The first and second stators of the first and second motor mechanisms are housed in one motor case, and the first and second stators of the first and second motor mechanisms are fixed to the motor case at two axial positions. A first bearing housing holding a second bearing bearing in both radial directions is supported at one end of the motor case,
A second bearing housing holding a second bearing for bearing the second rotor shaft in both the thrust and radial directions is supported at the other end of the motor case, and the first bearing is provided outside the first bearing.
A first detecting member for detecting the rotating state of the rotor shaft, and a second detecting member for detecting the rotating state of the second rotor shaft outside the second bearing. Shaft integrated motor.