阅读说明：本技术 机器人用壳体以及机器人 (Housing for robot and robot ) 是由 中山一隆 于 2020-11-17 设计创作，主要内容包括：本发明提供一种机器人用壳体(1A、1B、1C、1D)以及机器人,其能够在保持强度的同时进一步实现轻量化,并且能够降低生产成本。机器人用壳体(1A、1B、1C、1D)在中空的树脂制的主体部(2)上具备两个安装用开口部(4)和一个作业用开口部(7),安装用开口部(4)使主体部的内外连通,两个安装用开口部设置在主体部的两端部,在安装用开口部的周围的构成主体部的树脂中埋入有构成安装面(3a)的金属部件(3),金属部件(3)具备供安装螺钉贯穿或紧固的安装孔(5),安装螺钉用于向安装面进行安装,并且金属部件(3)以使安装面露出的状态埋入于树脂中,利用作业用开口部,能够向两个安装用开口部分别安装部件。(The invention provides a housing (1A, 1B, 1C, 1D) for a robot and the robot, which can keep the strength and further realize the light weight and reduce the production cost. The housing (1A, 1B, 1C, 1D) for the robot is provided with two mounting openings (4) and one working opening (7) on a hollow resin main body part (2), wherein the mounting openings (4) communicate the inside and the outside of the main body part, the two mounting openings are arranged at two end parts of the main body part, a metal member (3) forming a mounting surface (3a) is embedded in the resin forming the main body part around the mounting openings, the metal member (3) is provided with a mounting hole (5) for a mounting screw to penetrate or fasten, the mounting screw is used for mounting to the mounting surface, the metal member (3) is embedded in the resin in a state that the mounting surface is exposed, and the members can be respectively mounted to the two mounting openings by using the working openings.)

1. A housing for a robot is characterized in that,

the hollow resin main body is provided with two mounting openings for communicating the inside and outside of the main body and one working opening,

two of the mounting openings are provided at both ends of the main body,

a metal member constituting a mounting surface is embedded in the resin constituting the main body portion around the mounting opening,

the metal member has a mounting hole through which a mounting screw for mounting to the mounting surface is inserted or fastened, and is embedded in the resin in a state where the mounting surface is exposed,

the work opening portion allows a component to be mounted on each of the two mounting opening portions.

2. The housing for a robot as set forth in claim 1,

the work opening is configured to have a position and a size that allow the component mounted to each of the two mounting openings from outside the work opening to pass through the main body.

3. The housing for a robot as set forth in claim 1 or 2,

the metal member is a flat plate-like member,

the mounting holes are a plurality of through holes penetrating the metal member in a plate thickness direction.

4. The housing for a robot as set forth in claim 1 or 2,

the metal member is embedded in the resin in a state where a contact surface is exposed around the mounting hole on a side opposite to the mounting surface.

5. The housing for a robot as set forth in claim 4,

the metal member is a flat plate-like member,

the mounting holes are a plurality of screw holes penetrating the metal member in a plate thickness direction.

6. The housing for a robot as claimed in any one of claims 1 to 5,

the work opening is disposed at the center of the two attachment openings.

7. The housing for a robot as claimed in any one of claims 1 to 6,

the mounting surfaces of the two mounting openings are arranged in a perpendicular positional relationship with each other.

8. The housing for a robot as set forth in claim 7,

the main body is formed in a tubular shape bent in an L-shape,

the mounting openings are disposed at both ends of the main body,

the working opening is disposed at a bent position of the main body.

9. The housing for a robot as claimed in any one of claims 6 to 8,

the robot housing includes a cover body attached to the main body so as to be capable of opening and closing the working opening,

another metal member is embedded in the resin constituting the main body portion around the working opening,

the other metal member is provided with screw holes to which screws for attaching the lid body to the work opening portion are fastened.

10. The housing for a robot as claimed in any one of claims 6 to 8,

the robot housing includes a cover body having a snap-fit structure attached to the main body portion so as to be capable of opening and closing the working opening portion,

the main body part is embedded and sealed through the buckling and matching structure of the cover body.

11. The housing for a robot as claimed in any one of claims 1 to 10,

the robot housing includes a reinforcing metal member that connects the two metal members provided in the two attachment openings to each other.

12. The housing for a robot as set forth in claim 9,

the robot housing includes a reinforcing metal member that connects the two metal members provided in the two attachment openings and the other metal member.

13. The housing for a robot as claimed in any one of claims 1 to 12,

the metal member is embedded in the resin constituting the main body by insert molding.

14. The housing for a robot as set forth in claim 11 or 12,

the metal member and the reinforcing metal member are embedded in the resin constituting the main body by insert molding.

15. The housing for a robot as claimed in any one of claims 1 to 14,

the housing for the robot is integrally formed by injection molding.

16. The housing for a robot as claimed in any one of claims 1 to 15,

the resin constituting the body portion has flame retardancy such that the flame duration is 10 seconds or less and 127mm or more is not burned even if the resin is disposed in a vertical direction and is brought into contact with a fire for 10 seconds.

17. The housing for a robot as claimed in any one of claims 1 to 15,

the outer surface of the resin constituting the main body is covered with a coating material having flame retardancy of 10 seconds or less in flame duration and 127mm or more in incombustibility even if the coating material is vertically arranged and brought into contact with a fire for 10 seconds.

18. A robot is characterized by comprising:

at least one housing for a robot as claimed in any one of claims 1 to 17.

Technical Field

The invention relates to a housing for a robot and a robot.

Background

In general, components of an industrial robot are made of metal such as aluminum alloy in order to reduce weight and secure strength (see, for example, patent document 1).

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2013-018058

Disclosure of Invention

Problems to be solved by the invention

However, there is a limit to weight reduction of the metal component, and in order to manufacture the mounting surface for mounting other components such as the actuator with high accuracy, it is necessary to process the mounting surface with high accuracy, and therefore, there is a disadvantage that the production cost is high.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a housing for a robot and a robot, which can achieve further weight reduction while maintaining strength and can reduce production cost. The housing for the robot of the present application is defined as a housing strength member of a monocoque structure covering a base portion connecting links.

Means for solving the problems

One aspect of the present invention is a housing for a robot, which includes a hollow resin main body portion, two mounting openings for communicating an inside and an outside of the main body portion, and one working opening, the two mounting openings being provided at both end portions of the main body portion, wherein a metal member constituting a mounting surface is embedded in a resin constituting the main body portion around the mounting openings, the metal member including mounting holes through which mounting screws for mounting to the mounting surface are inserted and fastened, the metal member being embedded in the resin in a state in which the mounting surface is exposed, and wherein members can be mounted to the two mounting openings through the working opening, respectively.

Drawings

Fig. 1 is a schematic diagram showing an example of a robot to which a housing for a robot according to an embodiment of the present invention is applied.

Fig. 2 is a perspective view illustrating the housing for the robot of fig. 1.

Fig. 3 is a front view of the housing for the robot of fig. 2.

Fig. 4 is a side view of the housing for the robot of fig. 2.

Fig. 5 is a perspective view showing a metal plate provided in the attachment opening of the robot housing of fig. 2.

Fig. 6 is a longitudinal sectional view of the robot housing of fig. 2.

Fig. 7 is a partial longitudinal sectional view of the mounting opening of the robot housing of fig. 2.

Fig. 8 is an exploded vertical sectional view illustrating a work of connecting the robot housing of fig. 2 to the speed reducer of the first shaft and the speed reducer of the second shaft.

Fig. 9 is a rear view of a robot housing incorporating the speed reducer of fig. 8.

Fig. 10 is a vertical cross-sectional view showing a state in which the robot housing of fig. 2 is assembled to the speed reducer of the first shaft and the speed reducer of the second shaft.

Fig. 11 is a longitudinal sectional view showing a modification of the robot housing of fig. 2.

Fig. 12 is a longitudinal sectional view showing another modification of the robot housing of fig. 2.

Fig. 13 is a perspective view showing an example of a reinforcing metal member provided in the modified example of the robot housing of fig. 2 together with a metal plate.

Fig. 14 is a perspective view showing an example of another reinforcing metal member provided in the modified example of the robot housing of fig. 2 together with a metal plate.

Fig. 15 is a perspective view showing a modification of the robot housing of fig. 2 in which the reinforcing metal member of fig. 13 is embedded.

Fig. 16 is a modification of the second robot housing of fig. 1.

Fig. 17 is a longitudinal sectional view of the second robot housing of fig. 16.

Description of reference numerals:

1A: first shell (robot shell)

1B: second casing (casing for robot)

1C: third casing (casing for robot)

1D: fourth casing (casing for robot)

2: main body part

3: metal board (Metal parts)

3 a: mounting surface

3 b: watch surface (contact surface)

4: central hole (mounting opening)

5: through hole (mounting hole)

6. 13: mounting screw

7: center hole (opening for operation)

8: metal board (another metal component)

9: screw hole (mounting hole)

10: cover body

12: screw hole (mounting hole)

14: metal member for reinforcement

151: decelerator (component)

152: motor (component)

Detailed Description

The robot housings (hereinafter simply referred to as housings) 1A, 1B, 1C, and 1D and the robot 100 according to one embodiment of the present invention will be described below with reference to the drawings.

As shown in fig. 1, the robot 100 includes one or more housings 1A, 1B, 1C, and 1D according to the present embodiment. In the example of the robot 100 shown in fig. 1, four housings 1A, 1B, 1C, 1D are used.

The first casing 1A is supported to be rotatable about a vertical first axis a and the first arm 120 is supported to be rotatable about a horizontal second axis B with respect to the base 110 provided on the ground.

The second casing 1B is supported at the tip of the first arm 120 so as to be rotatable about a third axis C parallel to the second axis B, and supports a cylindrical second arm 130 so as to be rotatable about a fourth axis D along the longitudinal direction thereof.

The third casing 1C is fixed to the front end of the second arm 130, and supports the fourth casing 1D rotatably about a fifth axis E orthogonal to the fourth axis D. Also, the fourth housing 1D is supported to be rotatable about a fifth axis E relative to the third housing 1C, and supports the mounting flange 140 of the mounting end effector to be rotatable about a sixth axis F orthogonal to the fifth axis E.

The actuators 150 are directly fixed to both ends of the first, second, and fourth cases 1A, 1B, and 1D, the actuator 150 is directly fixed to one end of the third case 1C, and the actuator 150 is indirectly fixed to the other end via the second arm 130. The actuator 150 includes a speed reducer 151 and a motor 152, which will be described later. The first to fourth cases 1A, 1B, 1C, 1D are different in size but have substantially the same shape.

As shown in fig. 2 and 3, the housings 1A, 1B, 1C, and 1D of the present embodiment include a cylindrical resin body 2, and the outer shape of the body 2 has a square cross-sectional shape with rounded corners. As shown in fig. 4, the main body 2 is bent at a right angle at a central position in the longitudinal direction, and is formed into a hollow rectangular tube shape bent in an L shape as a whole.

The main body 2 includes flat plate-like metal plates (metal members) 3 at both ends in the longitudinal direction, and the metal plates 3 are embedded in a resin constituting the main body 2 by, for example, insert molding.

As shown in fig. 5, the metal plate 3 is formed in a ring shape having a circular central hole 4. The metal plate 3 is provided with a plurality of through holes 5 that penetrate in the plate thickness direction at intervals in the circumferential direction.

As shown in fig. 6, the two metal plates 3 at both ends of the main body 2 are arranged in a mutually orthogonal positional relationship. The central holes 4 of the two metal plates 3 constitute two attachment openings that open the internal space of the hollow main body 2 to the outside.

As shown in fig. 6 and 7, the metal plate 3 has one surface in the plate thickness direction as the mounting surface 3a, and the entire mounting surface 3a is exposed. In the example shown in fig. 6, the mounting surface 3a is disposed outside the housings 1A, 1B, 1C, and 1D.

As shown in fig. 7, the other surface 3b of the metal plate 3 in the plate thickness direction is covered with the resin constituting the main body 2 in a state where the peripheral portion of the through-hole 5 is exposed. As shown by the chain line in fig. 7, the surface 3b of the metal plate 3 exposed around the through-hole 5 is exposed slightly larger than the outer diameter of the head 6a of the mounting screw 6, and functions as a contact surface of the mounting screw 6 inserted into the through-hole 5.

The mounting surface 3a of the metal plate 3 is disposed at a position protruding from the resin constituting the main body 2.

As shown in fig. 2 and 6, the main body 2 includes a rectangular working opening 7 at a bent position at the center in the longitudinal direction.

The working opening 7 is also formed by a central hole of the metal plate 8 by embedding an annular metal plate (another metal member) 8 in the resin constituting the main body 2, and opens the internal space of the main body 2 to the outside. The metal plate 8 is provided with a plurality of screw holes (mounting holes) 9 at intervals in the circumferential direction.

The "work" in the work opening 7 means that the speed reducer 151 and the motor 152, which are the mechanism components, are attached to the metal plate 3, or detached from the metal plate 3, or the motor 152 is replaced, or the connector for driving the umbilical member of the motor 152 is attached to or detached from the motor 152, or the umbilical member itself is replaced.

The working opening 7 is formed slightly larger than the mounting opening 4, forms an angle of 45 ° with respect to each of the two metal plates 3 forming the mounting opening 4, and is disposed on the wall surface of the body 2 between the two mounting openings 4. Thus, the working opening 7 is configured to have a position and a size through which a member attached to each of the two attachment openings 4 can pass, directly or indirectly, from the outside of the working opening 7 through the inside of the main body 2. Among the components that are directly or indirectly mounted are, for example, a speed reducer 151 and a motor 152 as shown in fig. 8.

In the case of fig. 8, the motor 152 needs to be sized and positioned in the working opening 7 so as to be able to pass through the working opening 7 even during maintenance work such as motor replacement. In a case where it is desired to house the reduction gear 151 itself in the main body 2 without exposing it, the working opening 7 needs to be set to a size through which the reduction gear 151 can pass. However, it is more difficult to secure the strength of the main body 2 as the size of the working opening 7 is larger. Therefore, it is preferable that the working opening 7 is single and can be accessed to any one of the two metal plates 3. Further, operability can be ensured not only by inserting the reducer 151 and the motor 152 but also by securing a mounting bolt, a long T-wrench, or a size that can be manually entered during work.

The working opening 7 is normally closed by a lid 10 described later when not in use.

Further, an opening having a size that does not affect the strength of the main body 2 may be provided separately from the working opening 7. The opening may be of a size that allows entry of a mounting bolt, an L wrench or a T wrench as a fastening tool for mounting a bolt, or a human hand, for example. As the lid of the opening, for example, a resin lid having a snap-fit structure, a lid using an elastic body that is elastically deformed such as rubber, or the like can be used.

The housings 1A, 1B, 1C, and 1D of the present embodiment are provided with a lid 10 that can close the working opening 7. The lid body 10 is provided with a plurality of through holes that penetrate in the plate thickness direction at intervals in the circumferential direction. The working opening 7 can be closed by inserting screws through the through holes of the lid 10 and fastening the screws to the screw holes 9 of the metal plate 8.

The operation of the housings 1A, 1B, 1C, and 1D and the robot 100 of the present embodiment configured as described above will be described below.

As shown in fig. 8, in order to configure the robot 100 using the cases 1A, 1B, 1C, and 1D of the present embodiment, for example, an input shaft of the reduction gear 151 whose output shaft is fixed to the base 110 is brought into close contact with the attachment surface 3a of the metal plate 3 having one of the attachment openings 4. Then, the mounting screws 6 passed through the through-holes 5 of the metal plate 3 from the inside of the main body 2 are fastened to the screw holes of the reducer 151 via the working openings 7.

The input shaft of the reduction gear 151 whose output shaft is fixed to the first arm 120 is brought into close contact with the mounting surface 3a of the metal plate 3 having the other mounting opening 4. Then, the mounting screws 6 passed through the through-holes 5 of the metal plate 3 from the inside of the main body 2 are fastened to the screw holes of the reducer 151 via the working openings 7.

In the example shown in fig. 8 to 10, the motor 152 that inputs the driving force to the first-shaft reduction gear 151 is disposed inside the main body 2 and is fixed to the input shaft of the first-shaft reduction gear 151. Further, a motor 152 that inputs a driving force to the reduction gear 151 of the second shaft is also disposed in the main body 2 and is fixed to the input shaft of the reduction gear 151 of the second shaft.

Thereby, a first shaft that rotates the first casing 1A about the vertical first axis a with respect to the base 110, and a second shaft that rotates the first arm 120 about the horizontal second axis B with respect to the first casing 1A are constituted.

In the example shown in fig. 8 to 10, each reduction gear 151 is provided with a center hole 151a penetrating along the center axis thereof. The motor 152 is eccentrically disposed at a position not overlapping the center hole 151 a. This allows the umbilical members including the power supply cable to the motor 152 to be routed from the base 110 side to the inner space of the first casing 1A and the inside of the first arm 120 through the center hole 151A of the reduction gear 151.

The second to fourth housings 1B, 1C, and 1D can be assembled in the same manner, and the robot 100 shown in fig. 1 can be easily configured.

In fig. 8, the reducer 151 and the motor 152 are directly coupled to each other, and the main body 2 may be provided with a mounting interface for the motor 152. The metal plate for mounting the motor may be embedded in the resin of the main body 2.

As described above, according to the cases 1A, 1B, 1C, and 1D of the present embodiment, the entire case is made of resin, compared to the case of being made of metal such as aluminum alloy, and therefore, the weight can be significantly reduced.

Further, since the metal plates 3 configured with high accuracy are manufactured by insert molding, the mounting surfaces 3a of the two metal plates 3 can be arranged with high accuracy without machining. This eliminates the need for machining, thereby reducing the production cost.

In particular, since the mounting surface 3a of the metal plate 3 is protruded from the resin constituting the main body 2, there are advantages as follows: the resin does not become an obstacle when the mounting surface 3a of the metal plate 3 is mounted on the decelerator 151.

In this case, the head portion 6a of the mounting screw 6 can be pressed against the contact surface, which is the surface 3b of the metal plate 3 opposite to the mounting surface 3a, by inserting the mounting screw 6 through the through-hole 5 provided in the metal plate 3 and fastening the mounting screw to the screw hole of the reduction gear 151.

That is, if resin is present between the head 6a of the mounting screw 6 and the reducer 151, the bolt cannot be completely tightened even by repeated tightening, and a sufficient axial force cannot be applied, so that there is a possibility that the mounting screw 6 may loosen due to repeated operation of the robot 100. In contrast, in the present embodiment, since only the metal plate 3 is disposed between the head 6a of the mounting screw 6 and the reduction gear 151, there are advantages as follows: fastening can be performed with sufficient fastening force, and loosening of the mounting screw 6 can be reliably prevented.

However, it is necessary to pay sufficient attention so that the metal plate 3 itself is not peeled off from the resin member of the main body 2 by a load. In view of this, as shown in fig. 7, it is preferable that the metal plate 3 has a side surface provided with a projection 11 projecting in the radial direction at a position spaced apart from the mounting surface 3a in the thickness direction.

In this way, since the cross-sectional shape of the metal plate 3 is configured to have a shape with recesses and projections in the longitudinal direction, the projections 11 can be caught by the main body portion 2 so that the metal plate 3 does not peel off if the resin member of the main body portion 2 is not broken. Further, the configuration in which the convex portion 11 is provided on the metal plate 3 is exemplified, but instead, a concave portion that is concave in the radial direction may be provided on the side surface of the metal plate 3 at a position halfway in the thickness direction.

Further, according to the cases 1A, 1B, 1C, and 1D of the present embodiment, the work opening 7 is disposed at the center of the two mounting openings 4, and the work of mounting the reduction gear 151 and the like to any one of the mounting openings 4, the work of wiring the umbilical member, and the like can be easily performed through the work opening 7. By sharing the working opening 7, the number of openings can be reduced and the strength of the cases 1A, 1B, 1C, 1D can be improved.

In the present embodiment, a rectangular tube shape in which the body 2 is bent in an L shape is illustrated. Alternatively, the body 2 may be formed in a cylindrical shape having any other cross-sectional shape such as a cylindrical shape. Instead of the cylindrical body 2 bent in an L shape, a straight cylindrical body 2 may be used.

In the present embodiment, the metal plate 3 of each mounting opening 4 includes a through hole 5 through which a mounting screw 6 is inserted. Alternatively, as shown in fig. 11, in the case where a through-hole is provided in a member attached to the attachment surface of the reduction gear 151 or the like, a screw hole 12 for fastening the attachment screw 13 may be provided in the metal plate 3. In this case, the contact surface of the surface 3b of the metal plate 3 opposite to the mounting surface 3a may not be exposed.

In the present embodiment, the attachment surface 3a of the metal plate 3 of each attachment opening 4 is disposed outside the main body 2. Alternatively, as shown in fig. 12, when a component such as a reduction gear 151 is disposed in the main body 2, the mounting surface 3a may be exposed to the inside of the main body 2.

The metal plate 3 may be arranged in an inner flange shape facing radially inward relative to the side wall of the body 2, or may be arranged in an outer flange shape facing radially outward relative to the side wall of the body 2.

As shown in fig. 13, the reinforcing metal member 14 of the metal plate 3 connecting the two attachment openings 4 may be embedded in the resin constituting the main body 2. The reinforcing metal member 14 has a shape along the side wall of the main body 2, and may be joined to the metal plate 3 by bolts, welding, or the like, or may be integrally formed with the metal plate 3.

By providing the reinforcing metal member 14, the rigidity of the cases 1A, 1B, 1C, 1D can be improved, and the stress at the time of load application can be reduced. The reinforcing metal member 14 may be provided in plural, or may be provided with a reinforcing rib. The reinforcing metal member 14 may be embedded in the resin constituting the main body 2 by insert molding together with the metal plate 3. For example, a part of the reinforcing bead may be exposed from the resin.

As shown in fig. 14, when the metal plate 8 is disposed in the working opening 7, the reinforcing metal member 14 may connect the metal plate 3 of the two mounting openings 4 and the metal plate 8 of the working opening 7. This can further improve the rigidity of the cases 1A, 1B, 1C, and 1D. Further, as shown in fig. 15, by disposing the reinforcing metal member 14 in the resin constituting the main body portion 2, the warpage of the resin after molding can be reduced.

In the present embodiment, the metal plate 3 as a ring-plate-shaped member having the central hole 4 constituting the mounting opening 4 and the plurality of through holes 5 around the central hole 4 is exemplified as the metal member, and instead, a plurality of washer-shaped metal members having a single through hole 5 may be arranged around the central hole 4 and embedded in the resin constituting the main body portion 2. The washer-shaped metal member may have a concave-convex shape as in the metal plate 3. The metal plates 8 may be provided in the same structure.

In the present embodiment, the main body 2 made of resin as a whole is explained, but instead, a main body in which the surface of a thin member made of metal such as aluminum is coated with resin may be used. By using the metal in combination, the rigidity of the main body 2 can be improved, and by using the metal and the resin in combination, the amount of the metal used can be reduced, and the weight can be reduced. Further, by forming the outer surface of the case 1A, 1B, 1C, 1D with a relatively soft surface, the case can be formed.

The robot housings 1A, 1B, 1C, and 1D according to the present embodiment may be integrally molded by injection molding.

In the present embodiment, a cover having a snap-fit structure may be used as the cover 10. In this case, the snap-fit structure of the lid 10 is attached to the main body 2 so as to be able to open and close the working opening 7, whereby the main body 2 can be closed by fitting the snap-fit structure into the working opening 7.

Further, as the resin constituting the main body portion 2, it is preferable to have a flame-retardant resin which has a flame duration of 10 seconds or less and cannot burn 127mm or more even if it is placed in a vertical direction and brought into contact with a fire for 10 seconds. Preferably, the sample pieces ((125 ± 5) × (13 ± 0.5) × t) mm are directly attached to a jig, a contact flame of 10 seconds is performed twice with a 20mm flame, the combustion time of each sample piece is 10 seconds or less, the total combustion time of five sample pieces is 50 seconds or less, and the combustion + flameless combustion time of each sample piece is 30 seconds or less, so that there is no combustion by the jig and the cotton disposed below the sample pieces is not ignited. According to this structure, have following advantage: even if the cases 1A, 1B, 1C, 1D are overheated for some reason, the self-extinguishing property can be ensured. It goes without saying that even if the flame retardancy does not satisfy the above-described conditions, the resin is a resin of a slightly low grade and can satisfy the functions as the housings 1A, 1B, 1C, and 1D.

In addition, as the resin itself, in addition to the case of using the above flame-retardant resin, even if the flame retardancy of the resin itself is low, a coating material having higher flame retardancy than the resin can be applied to the entire outer surface of the resin.

As the resin, any of thermosetting and thermoplastic resins can be used.

In addition, as the resin, any fiber-reinforced resin such as a glass fiber-reinforced resin and a carbon fiber-reinforced resin can be used. In the glass fiber reinforced resin, since the fibers are colorless and transparent, the coating cost can be reduced by mixing a color into the base material. In the carbon fiber-reinforced resin, since the carbon fibers are black, even if the base material is mixed with a color, the black color can be seen, and therefore, it is preferable to coat the outer surface with the aforementioned coating material having high flame retardancy.

In the present embodiment, the cross-sectional profile shape of each of the two portions of the body 2 parallel to the mounting surface 3a of the metal plate 3 is a quadrangle, and the corners of the quadrangle are rounded. By forming the round shape, the corner R can be increased, and an effect of relaxing a contact force when a person comes into contact with the corner R can be expected.

In addition, in the present embodiment, a modification of the second casing 1B as shown in fig. 16 may also be adopted. In this case, as shown in fig. 17, the second case 1B is different from the second case 1B of fig. 6 in that two metal plates 3 are arranged so that mounting surfaces 3a are parallel to each other. The working opening 7 is provided on the surface of the resin body 2 located in the space sandwiched between the two metal plates 3. The mounting surfaces 3a of the two metal plates 3 are exposed toward the inside of the body 2.

In the embodiment of fig. 16, there are also cases where: one of the mounting surfaces 3a of the two metal plates 3 serves as a mounting surface for the actuator 150 for rotating the second arm 130, and the other serves as a mounting surface for directly mounting the first arm 120. In this case, it is preferable that the mounting surface on which the first arm 120 is directly mounted is exposed outward.

Thus, the speed reducer 151 and the like are accommodated in the main body 2 through the work opening 7, and are fixed with bolts from the outside of the main body 2 with the surface 3b as a contact surface in a state of being in contact with the mounting surface 3a of one of the metal plates 3. A link member or the like is attached to the attachment surface 3a of the other metal plate 3. Further, the reinforcing metal member 14 interconnecting the metal plate 3 and the metal plate 8 may be embedded in the resin constituting the main body 2.