JPH0615481Y2 - Motor unit - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor unit, and more particularly, to a motor unit having an internal pressure explosion-proof structure used for driving a movable part of an electric robot.

2. Description of the Related Art Conventionally, various hydraulically driven industrial robots have been proposed, but electric robots are being developed in place of hydraulically driven robots.

Since the electric robot has a structure in which each movable part is driven by a motor, it is necessary to use an explosion-proof structure when used in a highly flammable atmosphere, for example. For example, in an electric robot for painting that sprays flammable paint, it has been considered to make the electric system that easily causes sparks an internal pressure explosion-proof structure.

Therefore, in the electric robot, the motor unit is housed in an internal pressure case having a sealed structure, and the internal pressure case is attached to each part of the electric robot via a flange member. Further, a cable is inserted into the internal pressure case, and a gas supply tube for supplying a protective gas having a predetermined internal pressure and an exhaust tube are connected thereto.

Further, the motor unit is composed of a drive unit composed of a stator and a rotor, and a rotation detector such as a resolver for detecting the rotation position of the rotor shaft, and the gas supplied into the internal pressure case is the rotation detector and It reaches the tube for exhaust through the gap between the stator and the rotor. In this way, with the internal pressure explosion-proof structure that keeps the internal pressure case at a predetermined pressure (atmospheric pressure or higher), if gas in the tube leaks, it prevents the inflammable gas from entering and the power supply to the motor is reduced due to the pressure drop. It is configured to be shut off.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention In the motor unit having the above-described configuration, the motor unit is housed in the internal pressure case, so the internal pressure case is larger than the outer shape of the motor unit,
Furthermore, since it has an internal pressure explosion-proof structure, the thickness of the internal pressure case is increased to give the internal pressure case strength. That is,
In the conventional motor unit, a heavy internal pressure case,
Since the structure requires a flange member to mount the internal pressure case, there is a problem that the weight becomes considerably heavy. When the motor unit is attached to an articulated electric robot, each motor unit is attached to a movable part (for example, a pillar or an arm) of the electric robot while being housed in an internal pressure case. Therefore, in the electric robot to which the above motor unit is attached, since each motor unit has a heavy structure, an increase in the weight of each movable unit requires a larger driving torque, and the operating characteristics of each movable unit are increased accordingly. There is a problem that

Then, this invention aims at providing the motor which solved the said subject.

Means for Solving the Problems The present invention is directed to a motor housing having a stator directly fixed to an inner peripheral surface thereof and supporting a shaft of a rotor located inside the stator, and a motor housing fixed to the motor housing. A detector housing that houses a detector that detects the rotational position of the shaft; a gas supply path that is connected to the detector housing and supplies gas into the detector housing; the motor housing and the detector. A ventilation path that is provided in a partition wall between the housing and a gas passage for introducing gas supplied to the detector housing into the motor housing; and the stator and the rotor that are connected to the motor housing from the ventilation path. An exhaust path for exhausting the gas that has passed between and, and a seal member for sealing each connecting portion so that the motor housing and the detector housing have an airtight structure. Consisting of.

By fixing the motor housing and the detector housing in an airtight structure, it is possible to reduce the size and weight of the outer shell by eliminating the conventionally used internal pressure case. Further, since the gas supplied into the detector housing passes through the ventilation passage and passes between the stator and the rotor in the motor housing and is exhausted from the exhaust passage, air cooling of the stator and the rotor is required. Since the motor housing and the detector housing are partitioned from each other, it is possible to prevent the rotation detector from being affected by the magnetic field generated when the rotor is rotationally driven.

Embodiment FIG. 1 shows an electric robot to which an embodiment of the motor unit according to the present invention is applied, and FIGS. 2 and 3 show the motor unit which is the main part of the present invention.

First, a schematic configuration of the entire electric robot 1 will be described, and then a motor unit that is a main part of the present invention will be described.

In each figure, the electric robot 1 has a plurality of movable parts, and each movable part is driven by a motor to perform a predetermined operation. The electric robot 1 is used as a paint robot that sprays paint having flammability, for example.

On a base 2 of the electric robot 1, a turning base 3 that turns in the direction of arrow A is rotatably provided. Also, the base 2
A motor unit (shown by a broken line in FIG. 1) 4 for driving the turning base 3 is installed therein.

Brackets 3a and 3b stand upright on the upper surface of the swivel base 3, and a column 5 is swingably supported between the brackets 3a and 3b. The column 5 is rotated in the direction of arrow B by receiving the rotational driving force of the motor unit 6 provided outside the bracket 3a.

A bracket 5a for supporting the base portion 7a of the arm 7 is provided on the upper end of the column 5. The arm 7 rotates in the direction of arrow C to move the tip up and down. A wrist mechanism is provided at the tip of the arm 7, and a bellows-shaped rubber cover 8 is attached to the outer periphery of the wrist mechanism. Therefore, the wrist mechanism is not shown in FIG. A work jig (not shown) such as a paint gun is attached to the tip of the wrist mechanism.

9 is a motor unit for driving the arm, which is a bracket 3b
Is installed on the outside of. Reference numeral 10 is a link mechanism, and a horizontal link 11 connected to the output shaft of the motor unit 9,
One end is connected to the horizontal link 11, and the other end is provided with the vertical link 12 connected to the tip of the base 7a of the arm 7. Therefore, the rotational driving force of the motor unit 9 is the same as that of the link mechanism 10.
Is transmitted to the base portion 7a via, and thereby the arm 7 is rotationally displaced in the direction of arrow C.

Motor units 13, 14 and 15 for driving the wrist mechanism are attached to the rear portion of the base portion 7a of the arm 7. That is,
The wrist mechanism is rotated in the directions of arrows D, E, and F by receiving the rotational driving force from each of the motor units 13, 14, and 15.

Here, motor units 4, 6 for driving the joint mechanisms such as the swivel base 3, the support column 5, the arm 7, and the wrist mechanism.
9, 13, 14, and 15 will be described. Since each motor unit uses an AC motor and has substantially the same configuration, the configuration of the motor unit 6 for driving the column will be described in detail as an example.

As shown in FIGS. 2 and 3, the motor unit 6 is not housed in an internal pressure case having an internal pressure explosion-proof structure as in the conventional case, but the motor unit 6 itself has an internal pressure explosion-proof structure. That is, the motor unit 6 is formed by integrally assembling the motor housing 16 and the detector housing 17, and directly mounts the bracket 3a without a flange member.
(Indicated by a chain line in FIG. 2).

The motor housing 16 includes a hollow main body 16a and cases 16b and 16c fixed to both sides of the main body 16a. An annular stator (coil) is provided on the inner peripheral surface of the main body 16a.
18 is fixed. Inside the stator 18, the rotor 1
9 is inserted, and the rotor 19 is integrally assembled with the output shaft 20 of the motor unit 6. Output shaft 2
Both ends of 0 respectively project from the motor housing 16.

In FIG. 2, the left case 16b has a main body 16a at the right end.
Mounted on an outer periphery of a fixing portion 16b ₁ fixed to the body 16a by a screw 21, having a holding portion 16b ₂ which holds the bearing 22 to the left end. Further, as shown in FIG. ₃ , a flange portion 16b ₄ having a bolt insertion hole 16b ₃ for fixing the motor unit is provided on the right end surface of the case 16b. Further, the connection hole 16b ₅ of the case 16b is connected member 23a for connecting the exhaust side of the tube 23 is screwed.

The right case 16c is fitted to the outer periphery of the main body 16a at the left end, and is fixed to the main body 16a with the screw 24.
6c ₁ and holding part 1 for holding the bearing 25 at the right end
With 6c ₂ . Further, a connection member 27 of a tube 26 for supplying a protective gas is screwed into a connection hole 16c ₃ provided on the outer circumference of the case 16c, and a power cable 28 for power supply is inserted into the tube 26. There is.

The output shaft 20 is a bearing 2 held by the motor housing 16.
It is supported by 2, 25. Therefore, when a voltage is supplied from the power cable 28 to the output shaft 20, the rotor 19
Along with that, it is smoothly rotated.

Reference numeral 29 is an O-ring, which is mounted in the groove of the main body 16a,
The space between 6a and the cases 16b and 16c is hermetically sealed. 30 is an oil seal, which is the hole 16b ₆ of the case 16b.
It fits inside and seals between the output shaft 20 and the case 16b.

The detector housing 17 includes a main body 17a and a case 17b, and a resolver 31 that detects the rotational position of the output shaft 20 is housed inside. Since the structure of the resolver 31 is well known, its explanation is omitted here. Body 1
7a are flange portions 17a ₁ and 17a for mounting on both ends, respectively.
₂ and the flange portion 17a ₁ has a mounting bolt 32
By being fixed to the case end face 16c _4, it is integrally attached to the motor housing 16. Also, the case 17b
The flange portion 17b ₁ is fixed to the flange portion 17a ₂ of the main body 17a with a bolt 33. Further, a connection member 35 for connecting the tube 34 for supplying the protective gas into the detector housing 17 is screwed into the connection hole 17b ₂ provided on the outer periphery of the case 17b. This tube 3
A signal cable 36 for transmitting a signal from the detector 31 is inserted in the unit 4.

37 is an O-ring, which is the case end surface 16c ₄ and the flange portion 1
7a ₁ is sealed. An O-ring 38 seals between the flange portion 17a ₂ and the flange portion 17b ₁ .

As described above, the gaps between the respective members of the motor housing 16 and the detector housing 17, which form the outside of the motor unit 6, are O-rings 29, 37, 38 and the oil seal 30.
The motor unit 6 is hermetically sealed by a sealing member such as. Therefore, the motor housing 16 and the detector housing 17 are connected via the tubes 26 and 34.
The protective gas supplied therein fills the flow housings 16 and 17 as indicated by the arrow in FIG. Therefore, the inside of the motor unit 6 is maintained at a predetermined pressure equal to or higher than the atmospheric pressure.

As described above, the motor unit 6 includes the outer contour of the motor unit 6, that is, the motor housing 16 and the detector housing 17.
It has an internal pressure explosion-proof structure. Therefore, the motor unit 6 has a smaller shape than the conventionally used internal pressure case, and since it is mounted without using a flange, it is lighter in weight than the conventional one. Further, since the outside of the motor unit 6 has substantially the same size as that of the non-explosion proof structure and the outer diameter is reduced, the motor housing 16 and the detector housing 17 have a wall thickness larger than that of the conventionally used internal pressure case. Can be thin. From this point as well, the weight reduction of the motor unit 6 is promoted. Further, in the motor unit 6, the housing 1 in which the rotating members such as the rotor 19 and the output shaft 20 have a sealed structure with almost no extra space.
It is housed in Nos. 6 and 17, which is advantageous in terms of soundproofing, and the noise when driving the motor is low. Further, since the heat generated during the rotational driving is easily dissipated from the housings 16 and 17, the heat radiation effect is improved as compared with the conventional one. Reference numeral 40 is a bolt that fixes an annular plate 41 that holds the outer ring of the bearing 25. A hole 42 is formed at a concentric position where the bolt 40 is screwed.
As shown by the arrow in FIG. 2, the protective gas that has passed through the resolver 31 passes through this hole 42 and flows into the motor housing 16.

Therefore, the protective gas supplied from the tube 34 to the inside of the detector housing 17 serves as a partition wall that divides the detector housing 17 and the motor housing 16 from each other.
₂ passes through a hole (ventilation path) 42 formed in the motor housing 16, flows into the motor housing 16, and further, the stator 18 and the rotor 19
And is exhausted from the tube 23. Therefore, the stator 18 and the rotor 19 can be air-cooled, and the motor housing 16 and the detector housing 1 can be cooled.
Since it is partitioned from 7 and 7, it is not affected by the magnetic field generated when the resolver 31 rotationally drives the rotor 19,
Rotation can be accurately detected.

In addition, since the motor units 4, 9, 13, 14, 15 also have the same configuration as the motor unit 6, the turning base 3 to which the motor units 6, 9 are attached and the motor units 13, 14, 15 are attached. The weight of the arm 7 is reduced as compared with the conventional electric robot.

That is, the driving torque for driving the swivel base 3, the column 5, and the arm 7 is reduced accordingly, so that the operation characteristics of the electric robot 1 are improved and the painting work can be performed swiftly.

In the above embodiment, the connecting portions of the housings 16 and 17 are sealed by O-rings, but the seal member is not limited to the O-ring, and other packing members such as packing may be used. Is. Further, although the resolver is used as the detector in the above embodiment, it is not limited to this and other rotation detecting means may be used.

In the above embodiment, the motor housing 16 and the detector housing 17 can be divided into two or three members.
The invention is not limited to this, and each housing may be formed of one member or two or more members.

Further, although the AC motor is used for each motor unit in the above embodiment, the present invention is not limited to this, and another motor such as a DC motor may be used.

Advantages of the Invention As described above, the motor unit according to the present invention does not require the conventionally used internal pressure case and directly mounts the stator, the detector, etc. in the housing of the airtight structure, so that the outer portion is small. Therefore, it is possible to reduce the weight of the entire motor unit. Further, since the gas supplied into the detector housing passes through the ventilation passage and passes between the stator and the rotor in the motor housing and is exhausted from the exhaust passage, air cooling of the stator and the rotor is required. You can Moreover, since the motor housing and the detector housing are separated from each other, the rotation can be accurately detected without being affected by the magnetic field generated when the rotation detector rotationally drives the rotor. In addition, in an electric robot in which a motor unit is also attached to each movable part, the weight reduction of the motor unit improves the operating characteristics of each movable part and enhances the performance. In addition, since there is no extra space inside the housing, noise when driving the motor can be reduced, and the heat generated by driving the motor can be effectively dissipated from the motor housing, and the heat dissipation effect can be improved. Have.

[Brief description of drawings]

FIG. 1 is a perspective view of an electric robot to which an embodiment of a motor unit according to the present invention is applied, FIG. 2 is a vertical cross-sectional view for explaining an essential part of the present invention, and FIG. 3 is in FIG. FIG. 6 is a view seen from the direction of arrow G. 1 ... Electric robot, 3 ... Revolving base, 4, 6, 9 ... Motor unit, 5 ... Strut, 7 ... Arm, 13, 14, 15
... motor unit, 16 ... motor housing, 17 ... detector housing, 18 ... stator, 19 ... rotor, 20 ...
Output shaft, 23, 26, 34 ... Tube, 27, 35 ... Connection member, 29, 37, 38 ... O-ring, 30 ... Oil seal, 31 ... Resolver.

Claims (1)

[Scope of utility model registration request] 1. A motor housing having a stator directly fixed to an inner peripheral surface thereof and supporting a shaft of a rotor positioned inside the stator, and a rotational position of the shaft fixed to the motor housing. A detector housing accommodating a detector for detecting, a gas supply path connected to the detector housing for supplying gas into the detector housing, and a partition wall between the motor housing and the detector housing. A ventilation path that is provided in the motor housing and that introduces the gas supplied to the detector housing into the motor housing, and passes from the ventilation path between the stator and the rotor. A motor unit comprising an exhaust path for exhausting the gas, and a seal member for sealing each connecting portion so that the motor housing and the detector housing have an airtight structure. .