JPS63157634A - Motor drive unit - Google Patents

Abstract

PURPOSE:To make a bundled wire used for wiring unnecessary by using a wiring board for wiring between respective parts of a power circuit. CONSTITUTION:Fitting holes 11 in a printed board 1 of control circuit are made to engage with holding fixtures 21 of an upper frame 2 and held above said frame 2. A radiator 5 fitted with a power transistor 51 and power module 52, and a power resistor are screwed below a lower frame 4. A power board 3 connected with a power terminal 34, a circuit breaker 33 and others by soldering is placed above the lower frame 4, and the power resistor and others are fastened by a bolt 36 from above the power board 3 to a nut part of a terminal part 61 to perform an electric connection. After said assembly, the upper frame 2 is placed on the power board 3 put on the lower frame 4 and fastened to said frame 4 by a tapping screw 25 via a leg hole 24a in a leg part 24. Thus, all of the printed board 1, upper frame 2, power board 3, lower frame 4, radiator and power resistor 6 are formed into an integral body.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to a motor drive unit that houses electrical components used to control an AC motor.

(Prior Art) For example, a motor drive circuit shown in the circuit diagram of FIG. 4 is used as a control device for an AC motor that drives a main shaft or a feed shaft of a machine tool. The energizing terminal of the AC motor from the three-phase AC power terminals R, S, and T shown in Fig. 4! , V, and W include various electrical components such as a magnetic contactor A, a rectifying diode B, a smoothing capacitor C1, a regeneration transistor D, a transistor bridge E, and a filter F, as well as power resistors and fuses. electrical components are wired.

Among these electrical components, large electrical components are fixed by screws to a mounting plate, housed in a metal case made of sheet metal, and connected using an east wire.

(Problem to be Solved by the Invention) In the control device housed in the metal case described above, after fixing various electrical components of different shapes, they are connected to each other by the east line, which requires a lot of effort to assemble. However, it was difficult to automate the process.

Furthermore, since a metal case made of sheet metal is used as the external casing, problems arise in terms of cost and weight.

The present invention was made in view of these problems, and its purpose is to attach the motor control circuit and power circuit to separate plastic frames, and to connect the wiring between each part of the power circuit using a wiring board. To provide a motor drive unit that connects wires and eliminates the need for a sheet metal processed metal case and an east line for wiring.

(Means for solving the problem) A frame made of synthetic resin that holds a printed board on which control circuit components among the electrical components that drive and control the AC motor are assembled, and a power circuit component among the electrical components are fixed. A motor drive unit is provided that includes a frame made of synthetic resin and a wiring board that connects the power circuit components, and the wiring board is sandwiched between the two frames.

(Function) The printed board of the control circuit components is held in the upper plastic frame, the power circuit components that require heat dissipation are fixed to the lower plastic frame, and the wiring board with the power components connected is attached to the upper and lower plastic frames. In between,
Since the wires are connected to the power circuit components fixed to the lower plastic frame, there is no need for wiring or sheet metal processing of the metal frame, and the assembly work of the unit is simplified and made more compact.

(Example) Next, an example of the present invention will be described in detail using the drawings.

FIG. 1 is an exploded perspective view showing one embodiment of the motor drive unit of the present invention. In FIG. 1, 1 is a printed circuit board, which includes control semiconductor elements, resistors and capacitors for electric circuits associated therewith, etc. is attached and printed wiring, and constitutes a control circuit for an AC motor (not shown). A mounting hole 11 is provided near the peripheral edge of the printed circuit board 1, and the printed circuit board 1 is held on the upper frame 2 by engaging with the holder 21 of the upper frame 2. 12 is a connector for connecting an electric circuit.

The upper frame 2 is made of a molded synthetic resin material, has ribs 22 on the upper surface to reinforce the strength of the upper frame 2, and is also provided with a support portion 23 for supporting a large capacity capacitor 31. Note that a holder 21 is provided near the periphery of the upper surface of the upper frame 2, and a pin 21a is attached to the printed circuit board 1.
The printed circuit board 1 is inserted into the mounting hole 11 of the upper frame 2, and the printed circuit board 1 is held in the upper frame 2 by being held by the action of the claw portions 21b.

Reference numerals 24 denote legs provided at the four corners of the upper frame 2, which have leg holes 24a below, and are configured to be attached to the lower frame 4 with tapping screws 25 with a power board 3 to be described later in between.

The power board 3 is made of a multilayer printed circuit board, and is equipped with a large-capacity smoothing capacitor 31, an electromagnetic contactor 32, a circuit breaker 33, a power terminal 34, etc., which are power components for an AC motor, and the conductor parts are soldered to supply power. It is connected to the copper foil portion of the board 3.

FIG. 2 is an explanatory diagram showing an example of a method for attaching power components to a power board, and the circuit breaker 33 having the terminal pin 33a is located at a position corresponding to the board hole 33b drilled at a predetermined position on the power board 3. Terminal pin 3 placed on and inserted into
3a is fixed onto the power board 3 by soldering from the back side of the power board 3 to a copper foil portion that will serve as electrical wiring. Note that the power terminal 34 shown in FIG. 2 is also fixed by inserting the terminal pin 34a into a position corresponding to the board hole 34b of the power board 3 and soldering from the back side.

Next, the electric connection between the power board 3 and the power resistor 6 is made by connecting the nut part of the terminal part 61 buried in the power resistor 6.
By tightening the bolt 36 through the wiring hole 35 provided in the copper foil that serves as the wiring of the power board 3, a good conductive state can be obtained.

FIG. 3 is an explanatory diagram in which a floating nut 61a is used as the terminal portion 61, and the nut portion of the terminal portion 61 embedded in the power resistor 6 has, for example, a hexagonal floating nut 61a that allows a predetermined slight movement in the vertical and horizontal directions. Terminal part 6 so that
1, and although there is some play, it is constructed so that it does not rotate about the center axis of the screw. Therefore, even if there is some misalignment between the center axis of the bolt 36 and the center axis of the floating nut 61a when the bolt 36 is screwed in from above, the tip of the bolt 36 moves on the floating nut 61a and aligns the center axis of both. This means that the screws can be easily tightened, especially when a robot performs the screwing work.

The lower frame 4 is formed of a molded product of synthetic resin, and above it is an upper frame 2 equipped with a printed circuit board 1.
A power board 3 is attached thereto, and a heat radiator 5 to which a power semiconductor element requiring heat dissipation is attached and a power resistor 6 are attached below. A rib 41 that reinforces the lower frame 4 and supports the power board 3; an upper frame 42 that protects the parts mounting surface of the power board 3 from dust in the horizontal direction; and flange surfaces of the heat sink 5 and the power resistor 6. A lower frame 43 covering the lower frame 4 is provided on the upper and lower surfaces of the lower frame 4, respectively. Note that the upper frame 4
The dimensions of the opening part 2 are formed to be larger than the dimensions of the power board 3 and the arrangement of the legs 24 of the upper frame 2.
Since the dimensions of the power board 3 and the upper frame 2 are gradually narrowed down until they reach the predetermined mounting position, when installing the power board 3 and the upper frame 2 on the lower frame 4, they can be easily dropped into the opening of the lower frame 4. It is configured to be guided to a predetermined mounting position.

A power transistor 5 that requires heat radiation is provided on the upper surface of the heat sink 5.
A power module 52 such as 1 or a rectifier is attached, and each terminal part protrudes upward, and the power resistor 6 has a resistor with a large current capacity buried inside it, The terminal portion 61 is protruded.

Note that 44 is a fixing hole, which is a bolt hole for fixing to a heavy-duty power board (not shown).

Next, to explain the assembly of the motor drive unit of this embodiment, first, the printed circuit board 1 on which the control circuit is constructed.
The mounting hole 11 of the upper frame 2 is engaged with the holder 21 of the upper frame 2 to hold it above the upper frame. Next, the heat sink 5 and the power resistor 6 to which the power transistor 51 and the power module 52 are attached are screwed below the lower frame 4. Then power terminal 34 and circuit breaker 33
A power board 3 with power parts such as soldered and fixed on the upper part is placed above the lower frame 4, and a power transistor 51, a power module 52, etc. attached to the upper part of the heat sink 5, , connect the power resistor 6, etc. with a bolt from above the power board 3.

At 36, as shown in FIG. 2, it is tightened to a nut portion such as the terminal portion 61 to establish an electrical connection.

After the above assembly work, attach the upper frame 2 to the lower frame 4.
The power board 3 is placed on the power board 3 placed on the power board 3, and is fastened to the lower frame 4 with tapping screws 25 through the leg holes 24a of the upper frame 24. Finally, if the mounting hole 11 of the printed circuit board 1 in which the control circuit is configured is engaged with the holder 21 of the upper frame 2 and held above the upper frame, the printed circuit board 1, the upper frame 2, the power board 3, lower frame 4,
The heat sink 5 and the power resistor 6 are all integrated and assembled as a motor drive unit.

Although the present invention has been described with reference to the above embodiments, various modifications can be made within the scope of the gist of the present invention, and these are not excluded from the scope of the present invention.

(Effects of the Invention) According to the present invention, there is an upper frame that holds a printed circuit board having an electric circuit using a control semiconductor, and a lower frame that fixes a heat sink and a power resistor to which power transistors, rectifiers, etc. are attached. A power board with power components connected to it is sandwiched between these two frames, and components on the heat sink and power resistors are connected with screws, and both frames are made of plastic material. Since they are integrated by tightening them with tapping screws, assembly work is simplified.
This has the effect of facilitating automation using robots and the like.

In addition, according to the present invention, the upper power components of the power board sandwiched between the upper and lower frames are connected by soldering, and the lower power components are connected to the electric circuit by screws, which saves time and effort. This eliminates the need for wiring work between parts and work on the east line, resulting in the effect of improving work efficiency.

Further, in the present invention, since the upper and lower plastic frames are integrated, there is no need for a metal case made of sheet metal processing, and therefore there is an advantage that cost and weight can be reduced.

[Brief explanation of the drawing]

Fig. 1 is an exploded perspective view showing one embodiment of the motor drive unit of the present invention, Fig. 2 is an explanatory view showing an example of a method for attaching power components to a power board, and Fig. 3 is an explanatory view of a floating nut. , FIG. 4 is a circuit diagram showing an example of a motor drive circuit that controls an AC motor. 1.-Printed circuit board, 2.. Upper frame, 3..
Power board, 4... Lower frame, 5.- Heat sink, 6.
-Power resistor, 11...Mounting hole, 21-Holder, 2
5-Tapping screw, 33-Circuit breaker,
34--power terminal, 61--terminal section.

Claims (1)

[Claims] A frame made of synthetic resin that holds a printed board on which control circuit components are assembled among the electrical components that drive and control the AC motor, a frame made of synthetic resin that fixes the power circuit components among the electrical components, and the power circuit. What is claimed is: 1. A motor drive unit comprising: a wiring board for connecting parts; and the wiring board is sandwiched between both frames.