WO2019167418A1

WO2019167418A1 - Robot

Info

Publication number: WO2019167418A1
Application number: PCT/JP2018/048234
Authority: WO
Inventors: 原　淳一郎; 半田　浩之; 一大村田; 大治郎有澤
Original assignee: パナソニックＩｐマネジメント株式会社
Priority date: 2018-03-01
Filing date: 2018-12-27
Publication date: 2019-09-06

Abstract

A robot (10) is provided with: a motor; a ground wire (620) and a DC power supply wire (610) for supplying DC voltage; an inverter (320) having power semiconductor devices (333) which convert the DC voltage into AC voltage and supply the AC voltage to the motor; a control wire (630) for supplying a control signal to the inverter (320); and a second arm (120) that has the inverter (320) incorporated therein. The power semiconductor devices (333) are in contact with the inner surface of the second arm (120).

Description

robot

This disclosure relates to a robot having a robot arm.

Generally, a robot having a robot arm includes a motor that rotates the robot arm and a motor driving unit (inverter) for supplying an AC voltage to the motor. 2. Description of the Related Art A robot having a motor drive unit provided outside a robot arm and configured to supply AC power from the motor drive unit to the motor by a cable connecting the motor drive unit and the motor is widely used.

In the robot having such a configuration, the same number of motor drive units as the motors are provided. Therefore, as the number of robot arms increases, the number of motor drive units also increases. As a result, the number of cables for supplying an AC voltage from the motor drive unit to the motor increases. As a result, the total wiring length of the cable becomes long, and there is a problem that it is difficult to downsize the robot in order to secure the wiring space.

Therefore, reducing the total wiring length of the cable is being studied. For example, Patent Document 1 discloses a robot in which a motor drive unit is arranged in a robot arm and the motor drive units are connected in a daisy chain (a daisy chain connection).

JP 2017-189833 A

However, when the motor drive unit is arranged in the robot arm, the temperature of the robot arm rises due to heat radiation from the motor drive unit. Therefore, for example, in order to operate the robot as a collaborative robot that cooperates with an operator, it is desired that heat dissipation be improved. Patent Document 1 does not disclose the heat dissipation from the motor drive unit.

Therefore, the present disclosure provides a robot with improved heat dissipation.

A robot according to one embodiment of the present disclosure includes a motor, a power line and a ground line for supplying a DC voltage, an inverter having a power semiconductor device that converts the DC voltage into an AC voltage and supplies the AC voltage to the motor, A control line for supplying a control signal to the inverter and a first robot arm incorporating the inverter are provided, and the power semiconductor device is in contact with an inner surface of the first robot arm.

According to the robot according to one aspect of the present disclosure, heat dissipation is improved.

FIG. 1 is a perspective view showing an appearance of a robot according to an embodiment. FIG. 2 is a schematic diagram illustrating the configuration of the robot according to the embodiment. FIG. 3A is a diagram illustrating an example of an arrangement position of the inverter according to the embodiment. FIG. 3B is a diagram illustrating another example of the arrangement positions of the inverters according to the embodiment. FIG. 3C is a diagram illustrating still another example of the arrangement position of the inverter according to the embodiment. FIG. 4A is a cross-sectional view showing an example of an inverter built in the third arm according to the embodiment. FIG. 4B is a cross-sectional view illustrating another example of the inverter built in the third arm according to the embodiment. FIG. 5A is a schematic cross-sectional view showing an example of the configuration of the power semiconductor device according to the embodiment. FIG. 5B is a schematic cross-sectional view showing another example of the configuration of the power semiconductor device according to the embodiment. FIG. 5C is a schematic cross-sectional view showing still another example of the configuration of the power semiconductor device according to the embodiment. FIG. 6A is a cross-sectional view of the cable according to the embodiment. FIG. 6B is a diagram illustrating the length of the shortest side of the case according to the embodiment. FIG. 7A is a diagram illustrating a configuration of a robot according to a modification of the embodiment. FIG. 7B is a cross-sectional view showing a second arm portion according to a modification of the embodiment.

(Background to the disclosure)
As described in the background art, in a robot having a conventional robot arm, the inverter is arranged outside the robot, and the inverter and the motor arranged inside the robot are connected by wiring (for example, a wire line). . For this reason, wiring for driving and controlling the motor is arranged in the housing of the robot arm by the number of motors mounted on the robot. For example, in a 6-axis drive robot, which is a typical industrial robot, three power lines for U-phase, V-phase, and W-phase outputs, and 2 from a motor encoder (hereinafter also referred to as an encoder) Since five wires including the control lines are required for each motor, a total of 30 wires are arranged in the robot.

Therefore, a space for wiring such a large number of motor driving wires is required in the conventional robot, and it is difficult to reduce the size of the robot. Further, in the assembly work of the robot, there is a limit to shortening the work time for routing the wiring. In addition, problems such as disconnection of wiring are likely to occur during operation of the robot.

Therefore, it has been studied to reduce the total wiring length of the wiring. For example, Patent Document 1 discloses disposing an inverter in a robot arm and connecting the inverters in a daisy chain. Thereby, since the wiring length of the wiring connecting the inverter and the motor can be shortened, the total wiring length can be reduced. In addition, when the robot includes a plurality of robot arms, that is, includes a plurality of motors and inverters, the number of wirings for supplying DC voltage to the inverters and the inverters is reduced by daisy chain connecting the plurality of inverters. be able to. Therefore, the total wiring length can be further reduced. These have the following advantages.

Since the total wiring length is reduced, the robot arm can be reduced in size. As a result, the robot arm can be operated at high speed, and the robot arm can be passed through a narrow space (for example, in the case of assembly work, the space inside the assembly object), thus improving the convenience of the robot. To do.

Also, since the total wiring length is reduced, the weight of the robot can be reduced. Thereby, since the impact when the robot arm collides with something can be reduced, the safety of the robot is improved. For example, the robot can be safely operated as a collaborative robot that cooperates with the worker. In addition, since the output of the motor can be reduced by the weight reduction, the cost of the motor can be reduced. Further, the power consumption consumed by the robot can be reduced.

Also, since the number of wires is reduced, it is possible to shorten the work time required for the work of routing the wires in the assembly work of the robot. In addition, since the work of routing the wiring can be easily performed, the work can be performed even if it is not a skilled worker. As a result, the work efficiency in the assembly work of the robot is improved.

Also, the control device can be reduced in size compared to the case where the inverter is arranged in the control device (control box) outside the robot. Furthermore, the number of fans provided in the control device can be reduced.

Also, since the total wiring length is reduced, it is possible to reduce the disconnection of the wiring. As a result, the occurrence of a robot failure due to the disconnection of the wiring is reduced, so that the maintenance efficiency is improved.

Also, since the total wiring length is reduced, the cost required for manufacturing the robot can be reduced.

As described above, there are various merits by reducing the total wiring length. On the other hand, by disposing the inverter in the robot arm, the temperature of the robot arm rises due to heat radiation from the inverter. As described above, the conventional robot has not been able to reduce both the total wiring length and heat dissipation.

Therefore, the inventors of the present application have conducted intensive studies on a robot capable of reducing the total wiring length and suppressing the temperature rise of the robot arm. And it discovered that the rise in the temperature of a robot arm could be suppressed, maintaining the various merit described above by devising the arrangement position in the robot arm of the power semiconductor device which an inverter has.

Hereinafter, embodiments will be described with reference to the drawings. It should be noted that each of the embodiments described below shows a comprehensive or specific example. Numerical values, shapes, materials, constituent elements, arrangement positions and connection forms of constituent elements, and the like shown in the following embodiments are merely examples, and are not intended to limit the present disclosure. In addition, among the constituent elements in the following embodiments, constituent elements that are not described in the independent claims are described as arbitrary constituent elements.

In the present specification and drawings, the X axis, the Y axis, and the Z axis indicate the three axes of the three-dimensional orthogonal coordinate system. In the embodiment, the direction perpendicular to the installation surface on which the robot is installed is the Z-axis direction. For example, when the robot is installed on the floor surface, the Z-axis direction is a direction parallel to the vertical direction. The X-axis direction and the Y-axis direction are orthogonal to each other, and both are directions orthogonal to the Z-axis direction. Hereinafter, a direction parallel to the Z axis is also referred to as a vertical direction, and a direction orthogonal to the Z axis is also referred to as a horizontal direction. The horizontal direction is, for example, a direction parallel to the setting surface.

Each figure is a schematic diagram and is not necessarily shown strictly. Moreover, in each figure, the same code | symbol is attached | subjected to substantially the same structure, and the overlapping description may be abbreviate | omitted or simplified.

In this specification, terms indicating the relationship between elements such as parallelism, terms indicating the shape of elements such as a rectangular parallelepiped, and numerical values and numerical ranges are not expressions expressing only strict meanings. It is an expression that means to include a substantially equivalent range, for example, a difference of about several percent.

(Embodiment)
Hereinafter, the robot according to the present embodiment will be described with reference to FIGS. 1 to 6B.

[1. Robot configuration]
First, the configuration of the robot according to the present embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a perspective view showing an appearance of a robot 10 according to the present embodiment. FIG. 2 is a schematic diagram showing the configuration of the robot 10 according to the present embodiment. The robot 10 according to the present embodiment is a six-axis articulated robot, but is not limited to this. The robot 10 is, for example, an industrial-use robot that performs operations such as feeding, removing, transporting, and assembling precision equipment and parts constituting the precision device.

1 and 2, the robot 10 includes a robot arm 100, six motors (AC motors) including

motors

210 and 220, six

inverters including inverters

310 and 320, and a recovery. The apparatus 400, the control apparatus 500, and the base 700 are provided. The robot arm 100 includes a first arm 110, a second arm 120, a third arm 140, a fourth arm 150, and a fifth arm 160. The second arm 120 is, for example, a Y-shaped arm having a first arm portion 120a, a second arm portion 130, and a third arm portion 130a, and the first arm portion 120a, the second arm portion 130, and the third arm portion 130a. The arm unit 130a operates as a unit. In FIG. 1, only the inverter 320 built in the second arm 120 (for example, the second arm unit 130) among the six inverters is illustrated.

The robot 10 also includes a DC power supply line 610 and a ground line 620 for supplying a DC voltage to the inverter, a control line 630 for supplying a control signal to the inverter, and an AC voltage from the inverter to the motor. An AC power supply line 640 and an encoder signal line 650 for transmitting an output signal of an encoder (not shown) attached to the rotation shaft of the motor and detecting the rotation position of the rotation shaft of the motor to the inverter. The output signal includes, for example, information indicating the rotational position (angle) of the rotation shaft of the motor. Note that the DC power supply line 610 is an example of a power supply line.

The first arm 110 is connected to the base 700 so as to be rotatable around a first rotation axis a1 along the vertical direction. The second arm 120 is connected to the first arm 110 so as to be rotatable around a second rotation axis a2 along the horizontal direction. The third arm 140 is connected to the second arm 120 so as to be rotatable around a third rotation axis a3 along the horizontal direction. The fourth arm 150 is connected to the third arm 140 so as to be rotatable about a fourth rotation axis a4 along the horizontal direction. The fifth arm 160 is connected to the fourth arm 150 so as to be rotatable about a fifth rotation axis a5 along the horizontal direction. Further, an end factor (not shown) attached to the tip of the fifth arm 160 is connected to the fifth arm 160 so as to be rotatable about the sixth rotation axis a6. A kind of end factor is attached according to the application. Each arm is connected through a joint. The “joint portion” has a function of rotating two arms connected to each other (for example, adjacent arms).

As shown in FIG. 2, the first arm 110 includes a housing 112 that houses a motor 210, an inverter 310, and a recovery device 400. The second arm 120 is configured by a housing 122 that incorporates a motor 220 and an inverter 320. Although not shown, the third arm 140 to the fifth arm 160 are configured by a housing containing a motor and an inverter, like the second arm 120. In the example of FIG. 2, the collection device 400 is built in the first arm 110, but is not limited thereto, and may be built in any one of the first arm 110 to the fifth arm 160.

The casings of the first arm 110 to the fifth arm 160 including the

casings

112 and 122 are made of metal or resin. The metal is, for example, aluminum or an alloy (for example, Mg alloy).

The motor 210 is provided at the joint and generates a driving force that rotates the first arm 110 relative to the base 700. Specifically, the motor 210 is rotationally driven based on an alternating drive current that flows when a three-phase alternating voltage output from the inverter 310 is applied. The motor 210 is, for example, a servo motor. An encoder that detects a position signal of the rotation shaft is attached to the rotation shaft of the motor 210.

Similarly, the motor 220 to the fifth arm 160 (not shown) built in the second arm 120 are provided at the corresponding joints, and the second arm 120 to the fifth arm 160 are connected to each other. Generate driving force to rotate. Hereinafter, the motor 210 built in the first arm 110 to the motor built in the fifth arm 160 are also referred to as a motor 210 or the like.

The inverter 310 includes a power semiconductor device that converts a DC voltage supplied from the DC power supply unit 510 into an AC voltage (for example, a three-phase AC voltage) and outputs the AC voltage to the motor 210. The inverter 310 converts the input DC voltage into an AC voltage for driving the motor and supplies driving power to the motor 210 when the power semiconductor device is driven on and off according to the control signal received from the control unit 520. To do. The AC voltage is supplied to the motor 210 via the AC power supply line 640.

Similarly, inverters 320 (not shown) built in the second arm 120 to inverters (not shown) built in the second arm 120 supply driving power (AC power) to the corresponding motors. Hereinafter, the inverters 310 to 5 built in the first arm 110 are also referred to as inverters 310 and the like. The configuration of the inverter 310 and the like will be described later.

The switching element (power semiconductor switching element) included in the power semiconductor device is not particularly limited. For example, it may be a field effect transistor (eg, MOSFET) or an insulated gate bipolar transistor (IGBT). Alternatively, other transistors may be used. The switching elements are GaN power semiconductor elements based on GaN (gallium nitride), SiC power semiconductor elements based on SiC (silicon carbide), and Si based on Si (silicon). A power semiconductor element or the like can be used. Note that a GaN power semiconductor element is preferably used as the switching element from the viewpoint of reducing heat generation in the power semiconductor device.

Note that the motor 210 and the inverter 310 are arranged so as not to be in direct contact with each other. For example, the motor 210 and the inverter 310 are arranged with a gap of about 10 cm in the same casing. For example, the motor 210 and the inverter 310 are arranged so as not to be in thermal contact. Thereby, the loss in the inverter 310 can be reduced.

The recovery device 400 is connected to the DC power supply line 610 and the ground line 620, and recovers regenerative energy from each of the motor 210 and the like. The recovery device 400 includes, for example, a capacitor or a resistor. When the collection device 400 includes a capacitor, the collection device 400 collects the regenerative energy. Moreover, the collection | recovery apparatus 400 is collect | recovered by consuming regenerative energy, when a resistor is included. For example, one collection device 400 is provided for the robot 10.

The control device 500 is a device that performs overall control of the operation of the robot 10. The control device 500 is provided separately from the robot arm 100. The control device 500 includes a DC power supply unit 510 and a control unit 520. The DC power supply unit 510 and the control unit 520 are disposed in the casing of the control device 500.

The DC power supply unit 510 converts a power supply voltage, which is an AC voltage input from an AC power supply 800 (for example, a commercial power supply), into a DC voltage and outputs the DC voltage to the inverter 310 or the like. The DC voltage is supplied to the inverter 310 and the like via the DC power supply line 610 and the ground line 620. The type and configuration of the DC power supply unit 510 are not particularly limited, and are, for example, a PWM (Pulse Width Modulation) converter. Further, the conversion operation of the DC power supply unit 510 is controlled by the control unit 520.

Control unit 520 controls the conversion operation of inverter 310 and the like. The control unit 520 generates a control signal that is an operation command (for example, a switching command) for controlling the power conversion operation of the inverter 310 or the like so that the motor 210 or the like performs a desired rotation operation. For example, the control unit 520 generates a control signal for on / off control of a switching element such as the inverter 310 based on a DC voltage output from the DC power supply unit 510 and an output signal from the encoder. The control signal is supplied to the inverter 310 and the like via the control line 630.

In addition, when DC power supply unit 510 is a PWM converter, control unit 520 generates a control signal for controlling the switching operation of the switching element in the PMW converter, and outputs the control signal to DC power supply unit 510.

The control unit 520 executes various processes by causing a program execution unit such as a CPU (Central Processing Unit) or a processor to read and execute a software program recorded on a recording medium such as a hard disk or a semiconductor memory.

The DC power supply line 610 is a wiring that connects the DC power supply unit 510 and an input terminal (not shown) for power supply such as the inverter 310 and supplies a DC voltage from the DC power supply unit 510 to the inverter 310 and the like.

The ground line 620 connects the DC power supply unit 510 and a ground input terminal (not shown) such as the inverter 310. For example, the ground line 620 is grounded via the DC power supply unit 510.

The control line 630 connects the control unit 520 and the control signal input terminal (eg, gate terminal) of the inverter 310 and the like, and supplies a control signal (eg, clock signal) from the control unit 520 to the inverter 310 and the like. Wiring. The control line 630 may further include wiring for transmitting an output signal acquired by the inverter 310 or the like via the encoder signal line 650 to the control unit 520.

The AC power supply line 640 is a wiring that connects the motor 210 and the like to the output terminal of the inverter 310 and the like, and is a wiring that supplies a driving AC voltage for driving the motor 210 and the like. AC power supply line 640 includes three wires connected to each of the U phase, V phase, and W phase of motor 210 and the like. For example, an average current of about 2 A flows through the AC power supply line 640.

Encoder signal line 650 is a wiring for connecting motor 210 and the like to inverter 310 and the like, and supplies an output signal of an encoder attached to motor 210 and the like to inverter 310 and the like.

The base 700 is a fixed base to which the robot arm 100 is rotatably attached.

[2. Inverter installation position]
Next, the arrangement position of the inverter 310 and the like in the arm casing will be described with reference to FIGS. 3A to 3C. FIG. 3A is a diagram illustrating an example of an arrangement position of the inverter 320 according to the present embodiment. FIG. 3B is a diagram showing another example of the arrangement position of the inverter 320 according to the present embodiment. FIG. 3C is a diagram showing still another example of the arrangement position of the inverter 320 according to the present embodiment. In the following, description will be made mainly using the second arm portion 130 of the second arm 120 and the inverter 320, but the same applies to other arms and inverters. 3A and 3B, only the first arm 110 to the third arm 140 are illustrated.

As shown in FIG. 3A, the inverter 320 is disposed in contact with the inner surface of the housing 133 of the second arm portion 130 of the second arm 120, for example. Specifically, the inverter 320 is arranged in contact with the inner surface of the wall portion 133a constituting the housing 133. The contact of the inverter 320 with the inner surface of the housing 133 of the second arm unit 130 is included in the contact of the inverter 320 with the inner surface of the second arm 120.

As shown in FIG. 3B, the inverter 320 is disposed, for example, on the inner surface of the housing 133 of the second arm unit 130 and in contact with the inner surface of the third arm 140 side. Specifically, the inverter 320 is arranged in contact with the inner surface of the wall portion 133b constituting the housing 133. The wall part 133b is a wall part arranged on the other arm side among the

wall parts

133a and 133b constituting the housing 133. The second arm 120 is an example of a first robot arm, and the third arm 140 is an example of a second robot arm.

As shown in FIG. 3C, at least one of the DC power supply line 610, the ground line 620, and the control line 630 is inserted into the wall part 133 b (the X-axis minus side wall part shown in FIG. 3C) of the housing 133. A pair of openings (for example,

openings

133c and 133d) are formed. Openings are also formed at positions corresponding to the

openings

133c and 133d in the first arm portion 120a and the third arm 140.

The opening 133c is, for example, a hole for passing at least one of the DC power supply line 610, the ground line 620, and the control line 630 from one of the second arm part 130 and the third arm 140 to the other. That is, at least one of the

openings

133c and 133d is connected to the DC power line 610, the ground from one of the second arm 120 and the third arm 140 outside the second arm 120 to the other (for example, from the inside to the outside of the second arm 120). It may be a hole for passing at least one of the line 620 and the control line 630.

The opening 133d is, for example, a hole for passing at least one of the DC power supply line 610, the ground line 620, and the control line 630 from one of the first arm part 120a and the second arm part 130 to the other. That is, at least one of the

openings

133c and 133d has a DC power supply line 610 and a ground line 620 from one of the constituent parts (for example, the first arm part 120a and the second arm part 130) constituting the second arm 120 to the other. And a hole for passing at least one of the control lines 630. The shapes of the

openings

133c and 133d are, for example, circular, but are not particularly limited.

The inverter 320 is disposed between the

openings

133c and 133d on the inner surface of the wall 133b, for example. Inverter 320 is preferably arranged so that the direction in which

openings

133c and 133d are arranged and the longitudinal direction of inverter 320 are parallel from the viewpoint of more utilizing the space in housing 133. The inverter 320 being disposed between the

openings

133c and 133d includes, for example, that at least a part of the inverter 320 is disposed between the

openings

133c and 133d.

Although not shown, the DC power supply line 610, the ground line 620, and the control line 630 are also connected to the inverter 320.

Note that the

openings

133c and 133d are not limited to holes for passing the DC power supply line 610, the ground line 620, and the control line 630. For example, the opening 133c may be a hole for a joint part. The opening 133c is an example of a second opening, and the opening 133d is an example of a third opening.

[3. Inverter configuration]
Next, the configuration of the inverter 310 and the like will be described with reference to FIGS. 4A to 6B. FIG. 4A is a cross-sectional view showing an example of inverter 320 built in second arm 120 according to the present embodiment. 4A and 4B, an example in which the second arm 120 includes the inverter 320 in the second arm unit 130 will be described, but the present invention is not limited to this. Also, in FIGS. 4A and 4B, illustration of the motor arranged in the second arm 120 is omitted. 4A and 4B, for convenience, the DC power supply line 610 and the ground line 620 are illustrated as one straight line, and the three AC power supply lines 640 are illustrated as one straight line.

As shown in FIG. 4A, the inverter 320 includes a first circuit board 331, a second circuit board 332, a power semiconductor device 333, and a case 334.

The first circuit board 331 is a circuit board for converting a DC voltage into an AC voltage, and the power semiconductor device 333 is mounted thereon.

The second circuit board 332 is a circuit board for controlling the operation of the power semiconductor device 333 based on the control signal.

The first circuit board 331 and the second circuit board 332 are electrically connected by a signal line or the like, and the signal of the switching timing of the switching element is transmitted from the second circuit board 332 through the signal line or the like to the first circuit. It is transmitted to the substrate 331.

The power semiconductor device 333 converts the DC voltage supplied from the DC power supply unit 510 into an AC voltage. The power semiconductor device 333 includes a switch pair (for example, a U-phase arm) in which two switching elements (for example, an upper arm side switching element and a lower arm side switching element) are connected in series. The DC voltage is converted to an AC voltage output from the middle of the switching elements connected in series and output to the motor 210 and the like. The AC power supply line 640 is a wiring that connects the intermediate unit and the motor 210 and the like.

On the first circuit board 331, three power semiconductor devices 333 are mounted so as to be connected in parallel. Therefore, on the first circuit board 331, three switch pairs (U-phase arm, V-phase arm, and W-phase arm), that is, six switching elements are arranged. The six switching elements are ON / OFF controlled in accordance with a control signal input to the gate terminal, whereby the DC voltage is converted into a three-phase (U-phase, V-phase, and W-phase) AC voltage.

The case 334 includes a first circuit board 331, a second circuit board 332, and a power semiconductor device 333. Case 334 is formed of metal or resin. The case 334 may be made of aluminum, for example. Case 334 is an example of a housing. The case 334 is, for example, a hollow rectangular parallelepiped (box), but is not limited thereto.

The power semiconductor device 333 is arranged such that the surface opposite to the surface mounted on the first circuit board 331 (reverse surface) is in contact with the inner surface of the case 334. Specifically, the reverse surface of the power semiconductor device 333 is disposed in contact with the inner surface of the wall portion 334 a constituting the case 334. The power semiconductor device 333 and the case 334 are disposed so as to be in surface contact, for example.

As described above, the inverter 320 has the case 334 in which the power semiconductor device 333 is built. The power semiconductor device 333 is in contact with the inner surface of the case 334, and the outer surface corresponding to the inner surface of the case 334 is in contact with the inner surface of the housing 133. The contact of the power semiconductor device 333 with the inner surface of the housing 133 via the case 334 is an example of the contact of the power semiconductor device 333 with the inner surface of the housing 133.

It should be noted that an object other than the case 334 may be disposed between the power semiconductor device 333 and the housing 133. For example, a member such as a heat dissipation sheet may be arranged between the power semiconductor device 333 and the housing 133 in addition to the wall portion 334a of the case 334 or instead of the wall portion 334a. The power semiconductor device 333 is disposed with a space with respect to the inner surface of the wall portion 334a of the case 334, and the case 334 is disposed with a space with respect to the inner surface of the wall portion 133a of the housing 133. This is not included in the case where the power semiconductor device 333 is in contact with the inner surface of the housing 133.

Another configuration of the inverter will be described with reference to FIG. 4B. FIG. 4B is a cross-sectional view showing another example of inverter 320a built in second arm 120 according to the present embodiment.

As shown in FIG. 4B, the inverter 320a does not have the case 334, and the power semiconductor device 333 is in contact with the inner surface of the wall 133a of the housing 133. The power semiconductor device 333 is in contact with the inner surface of the wall 133a of the housing 133. The power semiconductor device 333 and the inner surface are in direct contact as shown in FIG. 4B, and the power semiconductor device 333 and the inner surface are in a heat dissipation sheet. Contact via a member such as. Note that the arrangement of the power semiconductor device 333 with a space from the inner surface of the housing 133 is not included in the contact of the power semiconductor device 333 with the inner surface of the housing 133. In the case of FIG. 4B, the method of fixing the first circuit board 331 to the casing 133 is not particularly limited, but is fixed to the casing 133 with screws 335, for example.

As shown in FIGS. 4A and 4B, the power semiconductor device 333 is in contact with the inner surface of the housing 133. In other words, the power semiconductor device 333 is in contact with the inner surface of the first arm 110.

Next, the configuration of the inverter will be described with reference to FIGS. 5A to 5C. FIG. 5A is a schematic cross-sectional view showing an example of the configuration of the power semiconductor device 333 according to the present embodiment. 5A to 5C, illustration of various lead wires and electrode pads is omitted.

As shown in FIG. 5A, the power semiconductor device 333 includes a substrate 333a, a semiconductor chip 333b, a filling layer 333c, and a heat dissipation layer 333d.

The substrate 333a is a substrate (for example, a metal base) on which the power semiconductor device 333 is mounted.

The semiconductor chip 333b is a power semiconductor chip mounted on the substrate 333a. The semiconductor chip 333b includes, for example, a switching element (for example, a MOSFET or an IGBT).

The filling layer 333c covers the semiconductor chip 333b. The filling layer 333c is formed of an insulating material such as resin. The filling layer 333c is formed of, for example, an epoxy resin.

The heat dissipation layer 333d covers at least a part of the filling layer 333c, and dissipates heat from the semiconductor chip 333b to the housing 133. For example, the heat dissipation layer 333d is in direct contact with the inner surface of the housing 133 and has a role of transferring heat of the semiconductor chip 333b transmitted through the filling layer 333c to the housing 133 side. Note that when the inverter 320 includes the case 334, the heat dissipation layer 333 d may be in direct contact with the inner surface of the case 334.

The heat radiation layer 333d is provided between the filling layer 333c and the housing 133 so as to be in contact with both. 5A shows an example in which the heat dissipation layer 333d is provided so as to cover the entire outer periphery of the filling layer 333c and to be in direct contact with the filling layer 333c and the housing 133.

The heat dissipation layer 333d may be formed including a resin or may be formed including a ceramic. When the heat dissipation layer 333d includes ceramic, an inorganic insulating material such as ceramic such as aluminum nitride (AlN) or silicon nitride (Si ₃ N ₄ ) is preferably used. Thereby, the heat dissipation layer 333d having high thermal conductivity and high heat resistance can be provided. In the case where the heat dissipation layer 333d includes a resin, a resin having high heat resistance may be used. Thereby, compared with the case where a ceramic is included, the power semiconductor device 333 can be reduced in weight and cost. The heat dissipation layer 333d may be a case that covers the filling layer 333c.

FIG. 5B is a schematic cross-sectional view showing another example of the configuration of the power semiconductor device 333 according to the present embodiment. As shown in FIG. 5B, the heat dissipation layer 333d may be provided so as to cover almost the entire upper surface of the semiconductor chip 333b (for example, the surface opposite to the mounting surface of the semiconductor chip 333b). The heat radiation layer 333d is preferably provided so as to cover at least the upper surface of the semiconductor chip 333b, for example. The heat dissipation layer 333d may be, for example, a metal plate made of metal. The heat dissipation layer 333d may be made of copper, for example. In the case where an insulating layer is formed on the surface of the semiconductor chip 333b, the heat dissipation layer 333d may be provided directly on the semiconductor chip 333b.

FIG. 5C is a schematic cross-sectional view showing still another example of the configuration of the power semiconductor device 333 according to the present embodiment. As shown in FIG. 5C, a heat radiation terminal 333e may be provided on the back surface (the surface on the first circuit board 331 side) of the semiconductor chip 333b. In other words, the semiconductor chip 333b and the first circuit board 331 may be thermally connected via the board 333a and the heat dissipation terminal 333e. Thereby, since the heat generated from the back surface of the semiconductor chip 333b can be transmitted to the first circuit board 331, the heat of the semiconductor chip 333b can be efficiently radiated.

Next, the size of the case 334 will be described with reference to FIGS. 6A and 6B. FIG. 6A is a cross-sectional view showing cable 600 according to the present embodiment. FIG. 6B is a diagram showing the length of the shortest side of the case according to the present embodiment.

As shown in FIG. 6A, the cable 600 is a wiring that incorporates a DC power supply line 610 and a ground line 620, and includes a DC power supply line 610, a ground line 620, an inner sheath 600a, and an outer sheath 600b.

The DC power supply line 610 includes a conductor 610a and an insulator 610b. For example, the outer diameter D1 of the cross section of the DC power supply line 610 is defined as the outer diameter of the insulator 610b out of the conductor 610a and the insulator 610b. The outer diameter D1 is, for example, 6 mm or less.

The ground wire 620 includes a conductor 620a and an insulator 620b. The outer diameter D2 of the cross section of the ground wire 620 is defined as, for example, the outer diameter of the insulator 620b among the conductor 620a and the insulator 620b. The outer diameter D2 is 6 mm or less, for example.

The outer diameter D3 of the cross section of the cable 600 is defined as, for example, the outer diameter of the outer sheath 600b. The outer diameter D3 is, for example, 15 mm or less.

As shown in FIG. 6B, if the length of one side (for example, side S1) of the three sides S1, S2, and S3 sharing one vertex V of the case 334 is the thickness L of the case, the case The thickness L of 334 is preferably equal to or less than the outer diameter D3 of the cross section of the cable 600 including the DC power supply line 610 and the ground line 620.

The thickness L may be smaller than the outer diameter D3. For example, the thickness L of the case 334 may be equal to or smaller than the outer diameter D1 of the cross section of the DC power supply line 610 or the outer diameter D2 of the cross section of the ground wire 620. For example, when the DC power supply line 610 and the ground line 620 are not built in the cable 600 and are individually wired, the thickness L is preferably equal to or less than the outer diameter D1 or the outer diameter D2. More preferably, the thickness L of the case 334 is less than or equal to the smaller outer diameter of the outer diameter D1 and the outer diameter D2.

From the viewpoint of further reducing the size of the inverter 320, the thickness L of the case 334 is, for example, the side having the shortest length among the three sides S1, S2, and S3 sharing one vertex V of the case 334 (see FIG. In the example of 6B, it is good that it is the length of side S1).

Note that the inverter 320 may be provided with a connection wiring (not shown) for connecting to the cable 600 or the DC power supply line 610 and the ground line 620 on the side surface of the case 334. This further reduces the thickness of the arm housing. Note that the side surface of the case 334 is a surface including the side S1 having the shortest length among the three sides, and may be, for example, the side surface A including the sides S1 and S2 or the side surface B including the sides S1 and S3. It may be.

Note that the outer surface of the wall portion 334a of the case 334 (that is, the surface in contact with the housing) is, for example, a surface that does not include the shortest side S1 among the three sides, and includes, for example, the sides S2 and S3. Surface. Thereby, the contact area between the case 334 and the housing 133 can be increased, so that the heat of the power semiconductor device 333 can be radiated more effectively.

[4. Effect etc.]
As described above, the robot 10 includes the motor, the DC power supply line 610 (an example of the power supply line) and the ground line 620 for supplying a DC voltage, and the power supplied to the motor by converting the DC voltage into an AC voltage. An inverter 320 including the semiconductor device 333, a control line 630 for supplying a control signal to the inverter 320, and a second arm 120 (an example of a first robot arm) incorporating the inverter 320 are provided. The power semiconductor device 333 is in contact with the inner surface of the second arm 120.

Thereby, since heat from the power semiconductor device 333 can be efficiently conducted to the second arm 120, it is possible to suppress an increase in the temperature of the second arm 120 without adding a configuration such as a fan. Therefore, according to the robot 10, heat dissipation is improved.

Further, the robot 10 described above incorporates the inverter 310 and the like in the robot arm 100 to reduce the total wiring length, and the power semiconductor device 333 such as the inverter 310 and the robot arm 100 (first arm 110 to fifth arm 160). The heat dissipation can be improved by contacting with. That is, the robot 10 can simultaneously reduce the total wiring length and improve the heat dissipation.

Furthermore, a third arm 140 (an example of a second robot arm) that is rotatably connected to the second arm 120 is provided. The power semiconductor device 333 is in contact with the inner surface of the second arm 120 and on the third arm 140 side. Specifically, the power semiconductor device 333 is in contact with the inner surface of the wall portion 133 b of the second arm 120.

Thereby, the power semiconductor device 333 can be brought into contact with a portion of the second arm 120 that is difficult for the operator to contact. That is, it is possible to suppress an increase in the temperature of a portion of the robot 10 that the operator may touch (for example, a portion of the housing 133). Therefore, in a situation where there is an operator who cooperates with the robot 10, heat dissipation can be improved while ensuring safety for the operator. For example, the operator can be prevented from being burned.

Further, the inverter 320 has a case 334 (an example of a housing) in which the power semiconductor device 333 is built. The power semiconductor device 333 is in contact with the inner surface of the case 334, and the outer surface corresponding to the inner surface of the case 334 is in contact with the inner surface of the second arm 120.

Thus, even if the inverter 320 has the case 334, the heat of the power semiconductor device 333 can be efficiently diffused to the second arm 120 via the case 334. Therefore, the heat dissipation of the robot 10 is further improved.

Further, the thickness L of the case 334 is equal to or less than the outer diameter D3 of the cross section of the cable 600 including the DC power supply line 610 and the ground line 620.

Thereby, since the thickness L of the case 334 can be made equal to or smaller than the outer diameter D3 of the cable 600, the second arm 120 can be made thin. That is, the second arm 120 can be reduced in size.

In addition, the thickness of the case 334 is equal to or less than the outer diameter D1 of the cross section of the DC power supply line 610 or the outer diameter D2 of the cross section of the ground wire 620.

Thereby, since the thickness L of the case 334 can be made equal to or less than the outer diameter D1 of the DC power supply line 610 or the outer diameter D2 of the ground wire 620, the second arm 120 can be made thinner. That is, the second arm 120 can be reduced in size.

The case 334 has a hollow rectangular parallelepiped shape, and the thickness L of the case 334 is the length of the shortest side S1 among the three sides S1 to S3 sharing one vertex V of the case 334.

Thereby, since the thickness L which is the length of the shortest side (for example, side S1) of the case 334 can be reduced, the second arm 120 can be reduced. That is, the second arm 120 can be reduced in size.

Also, the power semiconductor device 333 has a Gan power semiconductor element.

Thereby, since the amount of heat generated from the power semiconductor device 333 can be reduced, it is possible to further suppress the temperature of the robot 10 from rising.

Further, the first arm 110 includes a recovery device 400 that is connected to the DC power supply line 610 and the ground line 620 and recovers regenerative energy from the motor 210 and the like.

Thereby, the collection device 400 is disposed at a position closer to the motor 210 and the like as compared with the case where the collection device 400 is built in the control device 500 outside the robot arm 100. Therefore, the recovery device 400 can suppress an increase in the voltage of the DC power supply line 610 due to regenerative energy.

The second arm 120 has

openings

133c and 133d (second opening and second openings) for drawing out at least one of the DC power supply line 610, the ground line 620, and the control line 630 from the inside of the second arm 120 to the outside. The wall portion 133b is formed with an example of three openings. The inverter 320 is arranged between the

openings

133c and 133d in the inner surface of the wall 133b.

Thereby, since the space in the second arm 120 can be used effectively, the second arm 120 can be further reduced in size.

(Modification of the embodiment)
Hereinafter, the robot 10a according to this modification will be described with reference to FIGS. 7A and 7B. FIG. 7A is a diagram illustrating a configuration of a robot 10a according to the present modification. FIG. 7B is a cross-sectional view showing second arm portion 1130 according to a modification of the embodiment. In addition, it demonstrates centering around difference with the robot 10 which concerns on embodiment, the same code | symbol is attached | subjected about the same structure, and description may be abbreviate | omitted or simplified.

7A, a robot 10a according to this modification includes a second arm 1120 having a second arm portion 1130 instead of the second arm 120 provided in the robot 10 according to the embodiment. The second arm portion 1130 includes a housing 1133 that houses a motor (not shown) and an inverter 320 that is in contact with the inner surface of the wall portion 1133b.

As shown in FIG. 7B, an opening 1133 c is formed in the wall 1133 a of the housing 1133. The second arm portion 1130 has an opening / closing portion 1133d that covers the opening 1133c. The opening / closing part 1133d is a lid that can be opened and closed with respect to the opening 1133c. Note that the opening 1133c formed in the housing 1133 has a shape in which the inverter 320 in contact with the inner surface of the wall 1133b can be replaced. That is, the second arm 1120 has an opening / closing part 1133d that opens and closes an opening 1133c having a shape in which the inverter 320 can be replaced. In addition, the shape which can replace | exchange the inverter 320 is a shape corresponding to the magnitude | size or shape of the inverter 320, for example. The opening 1133c is an example of a first opening.

Although the material which comprises the opening / closing part 1133d is not specifically limited, For example, it forms with a metal or resin. The opening / closing part 1133d may be formed of, for example, a transparent resin material. The opening / closing part 1133d may be made of the same material as the housing 1133.

As described above, the second arm 1120 (an example of the first robot arm) of the robot 10a has the opening / closing part 1133d that opens and closes the opening 1133c (an example of the first opening) that can be replaced with the inverter 320.

Thus, maintenance of the inverter 320 built in the second arm 1120 can be easily performed. By providing the opening / closing part 1133d, for example, only the inverter 320 can be easily replaced. Further, during the operation of the robot 10a, the operator's safety can be ensured by closing the opening 1133c with the opening / closing part 1133d. Therefore, the convenience of the robot 10a is improved.

(Other embodiments)
As described above, the embodiments and modifications (hereinafter also referred to as embodiments and the like) have been described, but the present disclosure is not limited to the above-described embodiments and the like.

For example, in the above-described embodiment and the like, the power semiconductor device has been described with respect to the example having the filling layer and the heat dissipation layer, but is not limited thereto. The power semiconductor device may have at least one of the filling layer and the heat dissipation layer.

In the above-described embodiment and the like, the robot is an example of a 6-axis robot including the first to fifth arms, but is not limited thereto. The robot may be a robot having one or more arms.

In the above-described embodiment and the like, the example in which the second opening and the third opening are formed in the same wall portion in the housing has been described, but the present invention is not limited to this. For example, the second opening and the third opening may be formed in different wall portions. In this case, the disposition of the inverter on the imaginary line connecting the second opening and the third opening along the inner surface of the wall portion includes the disposition of the inverter between the second opening and the third opening. It is.

Further, the motor built in the arm in the above-described embodiment or the like is not limited to being a motor for rotating the arm containing the motor. The motor built in the arm may be, for example, a motor for rotating another arm different from the arm.

In the above-described embodiment and the like, an example has been shown in which the upper surface of the power semiconductor device (for example, the surface opposite to the mounting surface of the power semiconductor device) is in contact with the wall portion of the case, but the present invention is not limited to this. In the power semiconductor device, at least a part of the side surface may be in contact with the wall of the case in addition to the upper surface. Such a configuration may be realized, for example, by making the shape of the case according to the shape of the power semiconductor device.

In the above-described embodiment and the like, the example in which the number of power semiconductor devices mounted on the first circuit board is three is shown, but the number of power semiconductor devices is not particularly limited as long as the number is one or more.

In addition, the types (for example, model numbers) of the motors and the inverters in the above-described embodiments are not particularly limited, and may be the same or different from each other.

In addition, a form obtained by making various modifications conceived by those skilled in the art with respect to the above-described embodiment or the like, or realized by arbitrarily combining components and functions in each embodiment without departing from the gist of the present disclosure Forms to be made are also included in the present disclosure.

The present disclosure is applicable to a robot having a robot arm.

10, 10a Robot 100 Robot arm 110

First arm

112, 122, 133, 1133

Housing

120, 1120 Second arm (first robot arm)
120a

First arm portion

130, 1130 Second arm portion 130a

Third arm portion

133a, 133b, 334a, 1133a, 1133b Wall portion 133c Opening (second opening)
133d opening (third opening)
140 Third arm (second robot arm)
150 Fourth Arm 160

Fifth Arm

210, 220

Motor

310, 320, 320a Inverter 331 First Circuit Board 332 Second Circuit Board 333 Power Semiconductor Device 333a Substrate

333b Semiconductor Chip

333c Filling Layer 333d Heat Dissipation Layer 333e Heat Dissipation Terminal 334 Case 335 Screw 400 Collection Device 500 Control Device 510 DC Power Supply Unit 520 Control Unit 600 Cable 600a Inner Sheath 600b Outer Sheath 610 DC

Power Supply Line

610a,

620a Conductor

610b, 620b Insulator 620 Ground Line 630 Control Line 640 AC Power Supply Line 650 Encoder Signal Line 700 Base Stand 800 AC power supply 1133c Opening (first opening)
1133d Opening / Closing part a1 1st rotating shaft a2 2nd rotating shaft a3 3rd rotating shaft a4 4th rotating shaft a5 5th rotating shaft a6 6th rotating shaft A, B Side surface D1-D3 Outer diameter L Thickness S1-S3 Side V Vertex

Claims

A motor,
A power line and a ground line for supplying a DC voltage;
An inverter having a power semiconductor device for converting the DC voltage into an AC voltage and supplying the converted voltage to the motor;
A control line for supplying a control signal to the inverter;
A first robot arm containing the inverter;
The power semiconductor device is in contact with an inner surface of the first robot arm.
And a second robot arm rotatably connected to the first robot arm,
The robot according to claim 1, wherein the power semiconductor device is in contact with an inner surface of the first robot arm and on an inner surface of the second robot arm.
The inverter has a housing containing the power semiconductor device,
The power semiconductor device is in contact with the inner surface of the housing;
The robot according to claim 1, wherein an outer surface corresponding to the inner surface of the housing is in contact with an inner surface of the first robot arm.
The robot according to claim 3, wherein a thickness of the housing is equal to or less than an outer diameter of a cross section of a cable including the power supply line and the ground line.
The robot according to claim 3, wherein a thickness of the housing is equal to or less than an outer diameter of a cross section of the power line or the ground line.
The housing has a hollow rectangular parallelepiped shape,
The robot according to claim 4, wherein the thickness of the casing is the length of the shortest side among the three sides sharing one vertex of the casing.
The robot according to any one of claims 1 to 6, wherein the power semiconductor device includes a Gan power semiconductor element.
The robot according to any one of claims 1 to 7, wherein the first robot arm includes an opening / closing portion that opens and closes a first opening having a shape that allows the inverter to be replaced.
The robot according to any one of claims 1 to 8, further comprising a recovery device connected to the power line and the ground line in the first robot arm and recovering regenerative energy from the motor.
The first robot arm has a wall portion formed with a second opening and a third opening for inserting at least one of the power line, the ground line, and the control line,
The robot according to any one of claims 1 to 9, wherein the inverter is disposed between the second opening and the third opening in the inner surface of the wall portion.