JP2011088168A - Electric press apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electric press apparatus which facilitates maintenance-inspection operations such as the exchange work of a load cell. <P>SOLUTION: The electric press apparatus includes: a driving motor; a driving converter converting a rotational motion by the driving motor into a linear motion; a ram connected to the driving converter and performing linear reciprocation; a load cell detecting a load when a press operation is performed via the ram; and a controller controlling the driving motor based on a signal from the load cell. The load cell and a signal processing circuit amplifying the signal from the load cell and outputting the same to the controller are unitized so as to be a load cell unit. <P>COPYRIGHT: (C)2011,JPO&amp;INPIT

Description

  The present invention relates to an electric press device, and in particular, by integrating a load cell and a signal processing circuit used therein as a load cell unit, maintenance and inspection work such as load cell replacement work can be facilitated. It is related to something devised.

For example, Patent Document 1 discloses a configuration of an electric press device.

JP 2005-138110 A

  The electric press device disclosed in Patent Document 1 is generally configured as follows. First, there is a motor, and the ball screw is rotationally driven by this motor. A ball nut is screwed and arranged on the ball screw in a state where the rotation of the ball nut is restricted. A ram is integrated with the ball nut. A pressing body is attached to the tip of the ram. The ball screw is rotated in the same direction by rotating the motor forward and backward, thereby causing the ball nut and the ram to reciprocate linearly. By this reciprocating linear movement of the ram, for example, an arbitrary press is applied to a certain kind of work via the pressing body.

  A load cell is attached to the pressing body, and the load cell is configured to detect a load acting on the ram during pressing. The detection signal detected by the load cell is amplified through a differential amplifier circuit installed separately, digitized through an A / D converter, and input to a CPU (central processing unit). The CPU performs some kind of control based on the input load signal.

The conventional configuration has the following problems. In the case of the electric press apparatus disclosed in Patent Document 1, a load cell is used to detect a load during pressing, thereby controlling the press operation. At that time, the characteristics of the load cell may change due to aging or impact, and therefore, the load cell is removed and replaced as necessary. At that time, there is a problem in that it is necessary to perform readjustment of the calibration of the load cell and resetting the detection value at the rated load, which necessitates complicated work.

  The present invention has been made based on such points, and an object thereof is to provide an electric press device capable of facilitating a load cell replacement operation.

In order to achieve the above object, an electric press device according to claim 1 of the present invention includes a drive motor, drive conversion means for converting rotational motion by the drive motor into linear motion, and linear reciprocation coupled to the drive conversion means. In an electric press device comprising: a ram to be performed; a load cell that detects a load when performing a pressing operation via the ram; and a control unit that controls the drive motor based on a signal from the load cell. The load cell and a signal processing circuit that amplifies a signal from the load cell and outputs the amplified signal to the control means are unitized to form a load cell unit.
The electric press device according to claim 2 is the electric press device according to claim 1, wherein the signal processing circuit includes a differential amplifier circuit, an A / D converter, a CPU (central processing unit), and a serial communication IC. It is characterized by being.

As described above, the electric press device according to the first aspect of the present invention performs the linear reciprocating motion connected to the drive motor, the drive converting means for converting the rotational motion by the drive motor into the linear motion, and the drive converting means. An electric press device comprising: a ram; a load cell that detects a load when performing a pressing operation via the ram; and a control unit that controls the drive motor based on a signal from the load cell. And the signal processing circuit that amplifies the signal from the load cell and outputs it to the control means as a unit to form a load cell unit, so that readjustment of the load cell during load cell replacement work and detection value at rated load This eliminates the need to re-configure the load cell, etc., which greatly facilitates load cell replacement. To become.
The electric press device according to claim 2 is the electric press device according to claim 1, wherein the signal processing circuit includes a differential amplifier circuit, an A / D converter, a CPU (central processing unit), and a serial communication IC. Therefore, transmission / reception of signals between the signal processing circuit and the control means can be digitized.

It is a figure which shows one embodiment of this invention, and is a perspective view which shows the mode of the manufacturing line which uses the electric press apparatus. BRIEF DESCRIPTION OF THE DRAWINGS It is a figure which shows one embodiment of this invention, and is a perspective view which shows the structure of the whole electric press apparatus. It is a figure which shows one embodiment of this invention, and is an exploded perspective view which shows the structure of the principal part of an electric press apparatus. It is a figure which shows one embodiment of this invention, and is a side view which shows the structure of a load cell unit. It is a figure which shows one embodiment of this invention, and is a VV arrow line view of FIG. 1 is a diagram illustrating an embodiment of the present invention and a circuit diagram illustrating a configuration of a circuit. FIG. It is a figure which shows one embodiment of this invention, and is a perspective view which shows the relationship between an electric press apparatus and a motor drive controller.

Hereinafter, an embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a diagram showing a state in which the electric press device 1 according to the present embodiment is installed at a predetermined position of a certain production line 3. The production line 3 is provided with a belt conveyor mechanism 5, and a plurality of workpieces 7 are sequentially conveyed by the belt conveyor mechanism 5 in a direction indicated by an arrow a in the figure. The workpiece 7 is provided with a pressed portion 7a, and the pressed portion 7a is subjected to a predetermined press by the electric press device 1. And the said workpiece | work 7 of the state which pushed in the to-be-pressed part 7a predetermined amount is conveyed to the following process.
The electric press device 1 is supported and fixed by a support base 9.

  Next, the configuration of the electric press device 1 will be described. FIG. 2 is a diagram showing the overall configuration of the electric press apparatus 1. First, there is a housing 11, and a motor case 13 is provided and disposed in the housing 11. A drive motor 15 is built in the motor case 13, and a pulley 17 is fixed to a rotating shaft (not shown) of the drive motor 15.

  On the other hand, a ball screw 19 is housed inside the housing 11, and one end of the ball screw 19 is pivotally supported by a bearing member 21. A pulley 23 is fixed to the end of the ball screw 19 that penetrates the bearing member 21. A belt 25 is wound around the pulley 23 and the pulley 17 already described. By rotating the drive motor 15 forward and backward, the ball screw 19 rotates in the same direction via the pulley 17, the belt 25 and the pulley 23.

A ball nut 27 is screwed and disposed on the ball screw 19 in a state where the rotation of the ball nut 27 is restricted. A shaft 29 is connected to the ball nut 27, and a load cell unit 31 is connected to the tip of the shaft 29. As the ball screw 19 rotates, the ball nut 27, the shaft 29, and the load cell unit 31 move in the vertical direction in FIG.
An end member 33 is fixed to the lower end of the housing 11 in FIG. 2, and a bearing member 35 is housed in a through portion of the shaft 29 of the end member 33.

The load cell unit 31 is configured as shown in FIG. First, there is a load cell 41, and a male screw portion 43 is formed at the tip of the shaft 29 and a nut 45 is screwed together. A frame 47 is installed between the load cell 41 and the shaft 29, and a female screw portion 49 is formed on the frame 47. The frame 47 is screwed and fixed by a male screw portion 43 on the shaft 29 side, a nut 45, and a female screw portion 49 on the frame 47 side.

Another frame 51 is installed on the opposite side of the load cell 41 from the frame 47. The load cell 41 is installed inside the frame 51. The load cell 41 and the frame 51 are fixed to the frame 47 by a plurality of (eight in the case of this embodiment) fixing screw members 53.

Next, the configuration of the load cell 41 will be described with reference to FIGS. The load cell 41 includes a fixed base 61, and a ram 65 is connected to the fixed base 61 via a reduced diameter portion 63. A strain gauge 67 is attached to the reduced diameter portion 63. A recess 69 is formed on the bottom surface of the fixed base 61.

A signal processing circuit 70 is installed in the recess 69. The signal processing circuit 70 includes a printed circuit board 71. The printed circuit board 71 includes a strain amplifier 73 as a differential amplifier circuit, an A / D converter 75, a CPU (central processing unit) 77, an IC 79 for serial communication, Other electronic components 81 and 83 are installed.

FIG. 6 shows the configuration of a circuit including the strain gauge 67 and the load cell substrate 71. As shown in FIG. 6, a motor drive controller 91 as a control means is installed, and between this motor drive controller 91 and the printed circuit board 71, as shown in FIG. An encoder cable 95 is provided. The encoder cable 95 is from the encoder 97 provided in the drive motor 15, and the load cell cable 101 from the printed circuit board 71 side is joined there.

The operation will be described based on the above configuration.
First, regarding the operation of the electric press device 1, a plurality of workpieces 7 are sequentially conveyed in the direction indicated by the arrow a in FIG. At that time, the pressed portion 7a of the work 7 is pressed by the electric press device 1 and pushed in a predetermined amount. Pressed part 7a
Is pushed to a predetermined place by the belt conveyor mechanism 5.

The press operation of the electric press device 1 is as follows. First, when the drive motor 15 rotates forward, the ball screw 19 rotates in the same direction via the pulley 17, the belt 25, and the pulley 23. As a result, the ball nut 27 and the shaft 29 move forward in the direction of the workpiece 7. The load cell unit 31 is also moved forward by the forward movement of the shaft 29, whereby a predetermined press is applied to the pressed portion 7 a of the work 7 via the ram 65.

Further, the load during the press operation is detected via the load cell unit 31. That is, the load signal detected by the strain gauge 67 is amplified by the strain amplifier 73 and then digitized by the A / D converter 75. The digitized load signal is input to a CPU (Central Processing Unit) 77. The CPU 77 determines the control content based on the input digital load signal, and the control signal is output to the motor drive controller 91 via the serial communication IC 79 and the load cell cable 101. The motor drive controller 91 outputs an input control signal to the drive motor 15 via the motor drive cable 93 to control it. A signal from the encoder 97 is output to the motor drive controller 91 via the encoder cable 95.

As described above, according to the present embodiment, the following effects can be obtained.
First, since the load cell 41, the signal processing circuit 70, and the like are unitized and configured as the load cell unit 31, maintenance / inspection work such as replacement work is greatly facilitated. That is, when replacing, the load cell unit 31 is replaced, and at that time, the readjustment of the calibration of the load cell 41 and the resetting of the detection value at the rated load have already been completed for each unit. Therefore, it is only necessary to attach it as it is without performing any adjustment / setting work.
In addition, since the printed circuit board 71 is installed in the recess 69 of the fixing base 61, it is possible to prevent the load cell substrate 71 from being exposed and damaged. Further, since the printed circuit board 71 is not projected and arranged, the apparatus can be made compact.
In this embodiment, since the CPU 77 and the serial communication IC 79 are mounted on the printed circuit board 71 provided in the load cell 41, the load detection value is transmitted between the load cell 41 and the motor drive controller 91. As a result, the load cell cable 101 can be accommodated in the encoder cable 95. Therefore, space saving of wiring can be achieved.

The present invention is not limited to the one embodiment.
First, the configuration for unitization is not limited to the illustrated configuration, and various configurations are assumed.
In the case of the embodiment, the case where the printed circuit board 71 is installed in the recess 69 of the fixed base 61 is described as an example, but the present invention is not limited to this. In particular, the printed circuit board 71 may be installed without providing a recess.
In the above-described embodiment, the case of a strain gauge type load cell has been described as an example. However, the present invention is not limited thereto. For example, the same applies to a magnetostrictive type, a capacitance type, and a gyro type load cell. Applicable.

The present invention relates to an electric press device, and in particular, a load cell and a signal processing circuit used therein are unitized so that maintenance and inspection work such as load cell replacement work can be facilitated. For example, it is suitable for an electric press device for pressing and deforming a part of various parts.

DESCRIPTION OF SYMBOLS 1 Electric press apparatus 15 Drive motor 19 Ball screw 27 Ball nut 29 Shaft 31 Load cell unit 41 Load cell 67 Strain gauge 61 Fixing base 69 Recess 70 Signal processing circuit 71 Printed circuit board 73 Strain amplifier 75 A / D converter 77 CPU
79 IC for serial communication
81 Electronic component 83 Electronic component 91 Motor drive controller (control means)
93 Motor drive cable 95 Encoder cable 101 Load cell cable

Claims (2)

Drive motor, drive conversion means for converting rotational motion by the drive motor into linear motion, ram connected to the drive conversion means for linear reciprocation, and load detected when performing press operation through the ram A load cell, and a control means for controlling the drive motor based on a signal from the load cell, and an electric press device comprising:
An electric press device characterized in that the load cell and a signal processing circuit for amplifying a signal from the load cell and outputting the amplified signal to the control means are unitized into a load cell unit. In the electric press device according to claim 1,
An electric press device characterized in that a differential amplifier circuit, an A / D converter, a CPU (Central Processing Unit), and a serial communication IC are installed in the signal processing circuit.

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