Working machinery

Abstract

To provide a machine tool that is configured to detect and monitor a current state of a machining part or an execution situation, which can reduce failures due to disconnection and poor contact.SOLUTION: A machine tool (a pressure forging machine 1) is provided with: machining parts (a die 23, a rum 24 and a punch 26) that execute prescribed machining; a detecting part (a load cell 3) that is supplied with operation electric power to operate to detect a physical quantity (pressure forging force F) representing a current state of the machining part (the punch 26) or an execution situation of machining and outputs a detection signal; a non-contact transmitting part (4) that is supplied with operation electric power to operate to convert the detection signal to a transmission signal that can be transmitted in a non-contact manner and transmits the signal; and a wireless power supply part (5) that supplies operation electric power to the detecting part (the load cell 3) and the non-contact transmitting part (4) in a non-contact manner.SELECTED DRAWING: Figure 3

Description

Technical Field

[0004] , , ,

[0001] The present invention relates to a machine tool including a detection unit that detects a physical quantity representing the current state or machining operation status of a machining unit.

Background Art

[0002] As one form of a machine tool, a multi-step forging machine that performs forging on a workpiece using a plurality of sets of dies and punches is known. In a multi-step forging machine, a transfer device conveys the workpiece in a forward direction from an upstream process to a downstream process to proceed with the forging process. Here, the current state or machining operation status of the dies and punches is detected and monitored. For example, the forging machine of Patent Document 1 includes a pressure receiving member fitted between a base and a fixed die or between a movable part and a movable die, a load detection element attached to the pressure receiving member for detecting a load (forging force) as a change in electrical characteristics, and a flexible wiring member for electrically connecting the load detection element. According to this, it is said that the load can be detected every time forging is performed, and a full inspection of the workpieces can be carried out.

[0003] As the load detection element, for example, a converter of a bridge circuit disclosed in Patent Document 2 or a pressure sensor disclosed in Patent Document 3 can be applied. The abnormality detection device for the converter disclosed in Patent Document 2 includes means for switching each side of a converter of a bridge circuit for measuring strain and load, means for supplying a constant current to each side, means for measuring the voltage generated by the constant current, and means for determining an abnormality of each side of the bridge circuit from the voltage value. According to this, it is said that the disconnection state of each side of the bridge circuit and the connection cable can be detected.

[0004] Furthermore, the pressure sensor disclosed in Patent Document 3 comprises a piezoelectric element, a circuit board for processing electrical signals obtained from the piezoelectric element, and a lead portion connecting the piezoelectric element and the circuit board within a housing. One end of the lead portion is passed through the circuit board and connected on the opposite side, while the other end of the lead portion is connected to the piezoelectric element via a conductive elastic member. This is said to improve manufacturability through simplification of the internal structure, reduce manufacturing man-hours, and lower manufacturing costs. [Prior art documents] [Patent Documents]

[0005] [Patent Document 1] Japanese Patent Publication No. 2008-168305 [Patent Document 2] Japanese Patent Publication No. 2005-156193 [Patent Document 3] Japanese Patent Publication No. 2008-286589 [Overview of the project] [Problems that the invention aims to solve]

[0006] By the way, in the configuration of Patent Document 1, if a multi-core cable is used to wire the power supply and signal output of the load detection element to a separate control panel, the wiring length becomes long. For this reason, a structure is used in which intermediate boxes are appropriately placed along the wiring route. Such a wiring structure is prone to malfunctions such as wire breakage and poor contact. In detail, in addition to the long wiring length, the number of core wires in the multi-core cable increases according to the number of punches and dies, so the risk of wire breakage and poor contact within the intermediate box increases. Furthermore, in a configuration that detects the pressing force of the punch, the flexible multi-core cable used to adapt to the reciprocating motion deforms with each reciprocating motion, making it difficult to ensure sufficient durability and reliability.

[0007] Furthermore, because the weak signal output from the load detection element is transmitted over a long wiring length, it is susceptible to external noise (decreased signal-to-noise ratio). In addition, when a malfunction occurs that prevents proper measurement of the load (forging force), it is not easy to identify the cause of the failure, and recovery work requires a great deal of time and specialized skills. In particular, the inside of the forging machine frame is narrow, making it extremely difficult to investigate the cause by entering the space. Even if the technologies disclosed in Patent Documents 2 and 3 could be applied, it would still not be easy to identify whether the load detection element, the multi-core cable, or the relay box is the cause of the failure.

[0008] It should be noted that the monitoring items for dies and punches, in other words, the physical quantities representing the state of dies and punches or the working conditions, are not limited to the loads mentioned above. For example, configurations that monitor the temperature of dies and punches, and the three-directional acceleration of reciprocating punches, have been put into practical use. However, configurations that monitor temperature and acceleration also have problems, similar to load monitoring, such as the risk of wire breakage and poor contact, and the difficulty of recovery work. These problems are not limited to forging machines, but are common to various machine tools that detect and monitor the current state of the working part or the working conditions.

[0009] This invention has been made in view of the problems of the background technology described above, and aims to provide a machine tool that can reduce failures caused by wire breaks or poor contact in a configuration that detects and monitors the current state or working status of the working part. [Means for solving the problem]

[0010] The machine tool of the present invention comprises: a workpiece unit that performs predetermined work; a detection unit that operates when power is supplied to it and detects a physical quantity representing the current state or work status of the workpiece unit and outputs a detection signal; a non-contact transmission unit that operates when power is supplied to it and converts the detection signal into a non-contact transmission signal and sends it out; and a wireless power supply unit that supplies the power to the detection unit and the non-contact transmission unit in a non-contact manner. The manufacturing unit has a movable part that moves back and forth in the front-rear direction relative to the frame, the detection unit and the non-contact transmission unit are provided on the movable part, the wireless power supply unit has a plurality of primary coils arranged in the front-rear direction of the frame, an AC power supply that supplies AC power to the plurality of primary coils, a plurality of secondary coils arranged in the front-rear direction of the movable part, at least one of which faces the primary coils and receives the AC power non-contact when the movable part moves, and a power receiving circuit provided on the movable part that generates the operating power from the AC power received by the plurality of secondary coils, wherein three or more of the primary coils are arranged at a constant primary pitch distance, and three or more of the secondary coils are arranged at a non-constant secondary pitch distance. [Effects of the Invention]

[0011] In the machine tool of the present invention, the detection signal output by the detection unit is converted into a transmission signal by the non-contact transmission unit and transmitted non-contact, while the operating power of the detection unit and the non-contact transmission unit is supplied non-contact by the wireless power supply unit. Therefore, the cables used for power supply and signal output in the conventional technology can be eliminated or reduced, and as a result, failures caused by wire breaks or poor contact can be reduced. [Brief explanation of the drawing]

[0012] [Figure 1] This is a schematic plan view showing the overall configuration of a cold forging machine, which is a form of machine tool according to the first embodiment. [Figure 2] This is a side cross-sectional view showing the installation of a load cell for detecting the pressing force. [Figure 3] This is a schematic diagram illustrating the configuration for detecting and monitoring the cold-forming force. [Figure 4] This is a schematic perspective view showing the configuration of the wireless power supply unit. [Figure 5] This is a circuit diagram of the power receiving circuit of the wireless power supply unit. [Figure 6] This figure shows an example of a multi-step cold forging process performed on a workpiece. [Figure 7] Figure 6 illustrates the waveform of the forging force detected when the forging process shown is performed. [Figure 8] This is a schematic perspective view showing the configuration of the wireless power supply unit of the second embodiment. [Figure 9] This is a circuit diagram of the power receiving circuit of the wireless power supply unit in the second embodiment. [Modes for carrying out the invention]

[0013] 1. Overall configuration of the forging machine 1 in the first embodiment The overall configuration of the forging machine 1, which is one form of the machine tool according to the first embodiment, will be described with reference to FIG. 1. The forging machine 1 performs forging (predetermined machining) on a workpiece, plastically deform it, and manufactures parts and the like with a predetermined shape. The forging machine 1 is composed of a frame 21, a ram 24, seven sets of dies 23 and punches 26, a transfer device 27, a wire supply device 80, and a main drive unit 9, etc. The forging machine 1 is a horizontal multi-stage forging machine in which a plurality of punches 26 reciprocate in the horizontal direction. The forging machine 1 has the first to seventh processes formed by seven sets of opposing dies 23 and punches 26. In FIG. 1, the left-right direction of the paper surface is the front-rear direction of the forging machine 1, and the up-down direction of the paper surface is the width direction of the forging machine 1. In FIG. 1, the first to seventh processes are arranged from the upper side to the lower side of the paper surface in the width direction. Note that the number of processes of the forging machine 1 is not limited to seven processes, and generally ranges from 1 to 8 processes.

[0014] The frame 21 is a housing for arranging each part. Seven die holders 22 are provided side by side in the width direction at a position closer to the front of the frame 21. Each of the seven dies 23 is detachably attached to the rear part of each die holder 22. A predetermined processing die is formed on the rear side of each die 23 facing the left direction in the drawing. The die 23 holds the workpiece inside the processing die.

[0015] The ram 24 is generally rectangular in plan view and is arranged approximately at the center inside the frame 21. The ram 24 is one form of a movable part that reciprocates in the front-rear direction with respect to the frame 21. Seven punch holders 25 are provided side by side in the width direction at a position closer to the front of the ram 24. Each of the seven punches 26 is detachably attached to the front part of each punch holder 25. A predetermined processing die is formed on the front side of each punch 26 facing the right direction in the drawing. Each punch 26 reciprocates together with the ram 24. In each process, the punch 26 reciprocates in the front-rear direction while facing the die 23, and together with the die 23, performs forging on the workpiece. The die 23, the ram 24, and the punch 26 constitute a work execution part for performing a predetermined machining.

[0016] The wire supply device 80 is arranged from the position adjacent to the first process at the front part of the frame 21 forward. The wire supply device 80 is composed of a cutting blade 81, a fixed gripping part 82, a movable gripping part 83, etc. The movable gripping part 83 grips the long wire supplied from the front and moves it backward, thereby feeding the wire to the cutting blade 81. While the movable gripping part 83 releases the wire and returns forward, the fixed gripping part 82 grips the wire. The cutting blade 81 consists of an annular fixed blade and a movable blade through which the wire passes, and cuts the wire to produce a workpiece. The produced workpiece is pushed out toward the transfer device 27 by a pusher member (not shown). Usually, the wire has a circular cross-section, and the workpiece has a cylindrical initial shape. Examples of the materials of the wire and the workpiece include iron, aluminum, various alloys, etc. Note that instead of the fixed gripping part 82 and the movable gripping part 83, a wire feeding mechanism having one or more pairs of rollers that rotate while sandwiching the wire may be used.

[0017] The transfer device 27 is arranged from above the die holder 22 to the rear of the die 23. The transfer device 27 has eight pairs of fingers for gripping the workpiece. The first pair of fingers at the most upstream grips the workpiece pushed out from the wire supply device 80 and conveys it to the first process. The second to seventh pairs of fingers grip the workpiece in the upstream process and convey it to the downstream process. The eighth pair of fingers at the most downstream grips the workpiece in the seventh process and conveys it to an unloading part (not shown).

[0018] A main drive unit 9 is provided to drive the reciprocating motion of the punch 26. The main drive unit 9 drives the wire supply device 80 and the transfer device 27 together. The main drive unit 9 is composed of a main drive source 91 and various transmission mechanisms and cam mechanisms, etc. The main drive source 91 can be, for example, an induction motor or a synchronous motor that operates with a three-phase AC power supply. The driving force of the main drive source 91 is input to the crankshaft 96 via a flywheel 92, a clutch mechanism 93, a disk brake 94, and a speed reduction mechanism 95.

[0019] A connecting rod 29 is positioned between the crankshaft 96 and the ram 24. One end of the connecting rod 29 is connected to the crankshaft 96, and the other end is connected to the ram 24. When the crankshaft 96 is rotated by the main drive source 91, one end of the connecting rod 29 rotates along a circular orbit, and the other end of the connecting rod 29 reciprocates in the forward and backward direction. As a result, the ram 24 reciprocates in the forward and backward direction, and the seven punches 26 on the ram 24 also reciprocate in the forward and backward direction.

[0020] An electronic cam 9J is provided so as to contact the crankshaft 96. The electronic cam 9J detects the rotation angle of the crankshaft 96. Based on the detection signal from the electronic cam 9J, the position of the ram 24 within its operating range from rear dead center to front dead center is determined and reflected in the control of the main drive source 91. Alternatively, instead of the electronic cam 9J, a rotary encoder that detects the rotation angle of the crankshaft 96 without contact, or a proximity sensor or linear encoder that directly detects the front-rear position of the ram 24 can be used.

[0021] Seven kick-out cams 98 are provided above the connecting rod 29 and are rotationally driven. The kick-out cams 98 are arranged at equal intervals in the width direction and correspond to the positions of the first to seventh strokes, respectively. The kick-out cams 98 drive the punch-side kick-out pins (not shown) provided on each punch 26 in the front-rear direction. In addition, the driving force is branched and transmitted from the crankshaft 96 to the side shaft 99 via a branch gear pair 97.

[0022] The side shaft 99 transmits the driving force in an upward direction. The driving force branched upward rotates the transfer cam 9A. The transfer cam 9A drives the reciprocating movement of the transfer device 27 between processes. In addition, eight open-close cams 9C are connected to the side shaft 99 via the transfer drive 9B so as to be rotationally driven. The open-close cams 9C are arranged at equal intervals in the width direction. The open-close cams 9C drive each pair of finger in the transfer device 27 to open and close.

[0023] Furthermore, a cutter cam 9D is provided on the side shaft 99, and a pusher cam 9E, a feed cam 9F, and seven kickout cams 9H are connected to it. The cutter cam 9D drives the cutting motion of the cutting blade 81. The pusher cam 9E drives the pushing motion of the pusher member. The feed cam 9F drives the reciprocating motion of the movable gripping part 83. The kickout cams 9H are arranged at equal intervals in the width direction and correspond to the positions of the first to seventh steps, respectively. The kickout cams 9H for the first to seventh steps each drive the motion of ejecting the workpiece from the die 23.

[0024] 2. Load cell 3 and non-contact transmission unit 4 The forging machine 1 is equipped with a load cell 3 and a non-contact transmission unit 4 on the ram 24 to detect and monitor the forging force generated by the punch 26 during the forging process. As shown in Figure 2, the punch 26 is mounted approximately in the center of the punch holder 25. The load cell 3 is installed on the rear side of the punch 26 via pressure receiving members 261 and 262. The load cell 3 is provided individually for the punch 26 of the first to seventh processes. The load cell 3 is a form of detection unit that detects the forging force generated by the punch 26 in a time series and outputs a detection signal. The forging force is an example of a physical quantity that represents the working status of the punch 26. The load cell 3 is composed of four strain gauges connected in a bridge configuration. Note that pressure sensors or other detection methods other than the load cell 3 may be used in the detection unit.

[0025] The non-contact transmission unit 4 is a component that replaces the conventional signal output cable. As shown in Figure 3, the non-contact transmission unit 4 is mounted on the ram 24 using a mounting bracket (not shown). Because the mounting bracket offers flexibility in layout, the non-contact transmission unit 4 can be attached to various models of forging machines. The signal cables 31 of the load cells 3 for the first to seventh processes are connected to the non-contact transmission unit 4. The signal cables 31 serve two functions: transmitting the detection signals from the load cells 3 to the non-contact transmission unit 4, and supplying power from the non-contact transmission unit 4 to the load cells 3.

[0026] The contactless transmission unit 4 operates by receiving operating power from the wireless power supply unit 5, which will be described later. The contactless transmission unit 4 converts the detection signal received from the load cell 3 into a transmission signal that can be transmitted without contact and sends it out. Specifically, the contactless transmission unit 4 converts the detection signal into a wireless signal MS and transmits it. The receiving unit 6 that receives the wireless signal MS is located outside the frame 21.

[0027] The ram 24 can be optionally equipped with a second detection unit 35 according to the user's requirements. The second detection unit 35 detects a second physical quantity that differs from the forging force and outputs a second detection signal. In this optional configuration, the non-contact transmission unit 4 can supply power to the second detection unit 35 as needed. Furthermore, the non-contact transmission unit 4 can convert the forging force detection signal and the second detection signal together into a wireless signal MS and transmit it. Examples of the second physical quantity include the three-directional acceleration generated in the ram 24 (corresponding to the working status of the punch 26) and the temperature of each of the multiple punches 26 (corresponding to the current state). Thus, the non-contact transmission unit 4 may be provided in common for multiple types of detection units (load cell 3, second detection unit 35).

[0028] 3. Wireless power supply unit 5 The forging machine 1 includes a wireless power supply unit 5 for supplying operating power to the load cell 3 and the non-contact transmission unit 4 in a non-contact manner. The wireless power supply unit 5 is a replacement for the conventional power supply cable. The wireless power supply unit 5 consists of a power supply unit 51, an AC power supply 53, a power receiving unit 55, and a power receiving circuit 57, etc.

[0029] The power supply unit 51 and the AC power supply 53 are arranged on the frame 21. As shown in Figure 4, the power supply unit 51 has three or more (eight in the example in Figure 4) primary coils 52 arranged in the front-to-back direction on the frame 21. Each primary coil 52 consists of an iron core and windings, and various known shapes can be applied. Each winding of the multiple primary coils 52 is connected in parallel or in series to the AC power supply 53. The AC power supply 53 operates on a power supply of a common commercial frequency (50Hz, 60Hz) and supplies high-frequency AC power to the multiple primary coils 52. A power supply-side resonant capacitor may be added and connected in parallel or in series to the windings of the primary coils 52.

[0030] The power receiving unit 55 is positioned on the ram 24. As shown in Figure 4, the power receiving unit 55 has three secondary coils 56 arranged in the front-to-back direction on the ram 24. Each of the secondary coils 56 consists of an iron core and windings, and various known shapes can be applied. When the crankshaft 96 rotates as shown by arrow A1 in Figure 3, and the ram 24 reciprocates in the front-to-back direction as shown by arrow A2, the three secondary coils 56 move relative to the multiple primary coils 52 arranged in the front-to-back direction. At any position after relative movement, at least one secondary coil 56 faces the primary coils 52. Therefore, at least one secondary coil 56 can receive high-frequency AC power non-contact. Note that four or more secondary coils 56 may be provided.

[0031] A power receiving circuit 57, as shown in Figure 5, is provided adjacent to the power receiving unit 55. The power receiving circuit 57 is composed of three full-wave rectifier circuits 571 (equal to the number of secondary coils 56), a capacitor 572, and a DC converter 573. The full-wave rectifier circuit 571 is a known circuit in which four rectifier diodes are connected in a bridge configuration. The input side of the full-wave rectifier circuit 571 is connected to the winding of the secondary coil 56, and the output sides are connected in parallel with each other. A power receiving side resonant capacitor may be added and connected in parallel or in series with the winding of the secondary coil 56. The addition of a power supply side resonant capacitor and a power receiving side resonant capacitor improves contactless power supply performance.

[0032] Capacitor 572 is connected to the parallel connection of the three full-wave rectifier circuits 571. It is preferable to use an electric double-layer capacitor with a large capacitance as capacitor 572. This allows capacitor 572 to have both a smoothing function that reduces the pulsating component of the DC voltage output from the full-wave rectifier circuit 571, and a power backup function that maintains power for a predetermined time or longer in the event that the contactless power supply performance temporarily deteriorates.

[0033] The DC converter 573 is connected across the capacitor 572. The DC converter 573 converts the DC power output by the full-wave rectifier circuit 571 to generate DC operating power. This operating power is supplied to the non-contact transmission unit 4 via the power cable 58. For example, a commercially available DC / DC converter can be used as the DC converter 573. The non-contact transmission unit 4 adjusts the voltage of the operating power and supplies it as power to each of the load cells 3 via the signal cable 31. The non-contact transmission unit 4 also adjusts the voltage of the operating power as needed and supplies it as power to the second detection unit 35.

[0034] Here, as shown in Figure 4, multiple primary coils 52 are arranged in a line at a constant primary pitch distance D1. On the other hand, three secondary coils 56 are arranged in a line at non-constant secondary pitch distances (D21, D22). For example, the first secondary pitch distance D21 is set to be equal to the primary pitch distance D1, and the second secondary pitch distance D22 is set to be approximately 1.3 to 1.7 times the primary pitch distance D1. However, this is not limited to this, and the combination of non-constant secondary pitch distances (D21, D22) can be changed as appropriate. Also, the secondary pitch distances (D21, D22) may be smaller than the primary pitch distance D1. Furthermore, in configurations with four or more secondary coils 56, the secondary pitch distances D21 and D22 may be set alternately, and all secondary pitch distances may be different.

[0035] As described above, by setting the pitch distance, the three secondary coils 56 are aligned midway between the primary coils 52, preventing a significant decrease in contactless power supply performance. Furthermore, the wireless power supply unit 5 can perform contactless power supply even when the RAM 24 is stopped. Therefore, the wireless power supply unit 5 can always provide stable contactless power supply performance. This makes it possible to configure the power receiving circuit 57 without a rechargeable battery (secondary battery). By adopting a circuit configuration that does not require a rechargeable battery (secondary battery) or primary battery, the frequency and number of maintenance items can be significantly reduced.

[0036] 4. Receiving unit 6 The receiving unit 6 is provided, for example, in a separate control panel. The receiving unit 6 is configured using a computer device with wireless communication capabilities and operates on a general commercial frequency power supply. The receiving unit 6 receives the wireless signal MS transmitted by the non-contact transmission unit 4 and displays or records the detected forging force. For example, the receiving unit 6 may display and record all the waveforms of the forging force detected in each of the first to seventh punches 26. Alternatively, the receiving unit 6 may exclude some of the punches 26 and display or record only the forging force of a specific punch 26. Furthermore, depending on the performance constraints of the non-contact transmission unit 4, the receiving unit 6 may receive and display or record a sample waveform of the forging force generated in each of the punches 26 (for example, one waveform out of 10 waveforms). It is also preferable for the receiving unit 6 to perform moving average processing on the raw forging force data to smooth the waveform. Note that the moving average processing may be performed by the non-contact transmission unit 4.

[0037] The receiving unit 6 also functions as an abnormality detection unit that monitors whether the forging process is being performed correctly. Specifically, the receiving unit 6 determines abnormalities in the working condition of the punch 26 based on the detected waveform of the forging force. The receiving unit 6 uses three abnormality detection methods in combination: the envelope method, the integral method, and the differential method. In the envelope method, the forging process is tested in advance to determine a reference waveform and allowable variation range of the forging force that indicates a normal state. The receiving unit 6 compares the waveform of the forging force detected during the actual forging process after the test with the reference waveform and determines an abnormality if there is a difference that exceeds the allowable variation range.

[0038] In the integral method, the receiving unit 6 calculates the integral value of the forging force by integrating the waveform each time it acquires the waveform of the forging force. The receiving unit 6 then determines that there is an abnormality if the change in the integral value of the forging force from the previous value to the current value exceeds a predetermined amount. In the differential method, the receiving unit 6 calculates the differential value of the forging force by differentiating the waveform each time it acquires the waveform of the forging force. The receiving unit 6 then determines that there is an abnormality if the differential value of the forging force deviates from a predetermined allowable range.

[0039] 5. Examples of detecting the cold forging force F Next, an example of detecting the forging force F in the forging machine 1 will be explained with reference to Figures 6 and 7. When the forging process exemplified in Figure 6 is performed, the receiving unit 6 receives and displays the waveform of the forging force F exemplified in Figure 7. In Figure 6, the workpiece 8 is forged sequentially in each process from right to left. More specifically, the first process #1 is a blanking process, and the workpiece 8 is not forged. In the second process #2, the area around the tip of the workpiece 8 (lower end in Figure 5) is forged to form a tapered portion. In the third process #3, the diameter of the workpiece 8 from the middle to the tip is reduced to form the shaft portion 8A. In the fourth process #4, the base end side of the workpiece 8 (upper side in Figure 5) is forged to form a head portion 8H with a step and a taper. In the fifth process #5, a part of the head portion 8H of the workpiece 8 is enlarged to form a flange portion 8F. In the sixth process #6, a groove extending in the axial direction is formed in the shaft portion 8A of the workpiece 8. In step 7, the flange portion 8F of workpiece 8 is cold-formed (for example, shaped into a hexagon).

[0040] In Figure 7, the horizontal axis represents time T, and the vertical axis represents the forging force F, with the rated maximum forging force set to 1 (PU). The six graphs labeled #2 to #7 show the waveforms of the forging force F generated in the second process #2 to the seventh process #7 in Figure 6. The first process #1 is a blanking process, so the waveform of the forging force F is not shown. The time range shown in Figure 7 is a part of the cycle time of the reciprocating motion of the punch 26, and a portion of the time period when no forging force F is generated is omitted. As shown, the forging force F generated in the second process #2 to the seventh process #7 differs in the time period at which it is generated, and the maximum value of the forging force F also differs, ranging from approximately 0.30 to 0.76 (PU). Furthermore, a non-zero detection error is observed in the time period when it is estimated that no forging force F is generated.

[0041] The receiving unit 6 can determine the following various abnormalities by using the three abnormality determination methods described above in combination. Due to a transport error, workpiece 8 is not present in the process. Due to a transport error, workpiece 8 underwent two forging processes in the same stage (double forging). • Residual waste from punching processes. • Intrusion of foreign matter into the processing area. • Insufficient mass and length of workpiece 8. • Workpiece 8 is excessive in both mass and length. • Wear and tear on die 23 and punch 26. • Improper installation of die 23 and punch 26. • Damage such as cracks or chips in die 23 or punch 26. • Shortage of processing oils and lubricants.

[0042] In the forging machine 1 of this embodiment, the detection signal of the forging force F output by the load cell 3 is converted into a transmission signal by the non-contact transmission unit 4 and sent out non-contact, while the operating power of the load cell 3 and the non-contact transmission unit 4 is supplied non-contact by the wireless power supply unit 5. Therefore, the cables used for power supply and signal output in the conventional technology can be eliminated or reduced, and as a result, failures caused by wire breaks or poor contact can be reduced.

[0043] In particular, the load cell 3 and non-contact transmission unit 4 are provided on the reciprocating ram 24, eliminating the need for flexible multi-core cables to accommodate the reciprocating motion, resulting in a significant reduction in failures. Furthermore, even if a failure does occur, the location of the cause becomes easier to identify, enabling early recovery. In particular, the ability to simplify and facilitate root cause investigations by accessing narrow spaces inside the frame 21 is significantly reduced. In addition, wiring work during manufacturing and recovery is greatly reduced. Moreover, the signal transmission cable that was previously routed to a separate control panel has been replaced with a signal cable 31 to the non-contact transmission unit 4, shortening the transmission distance of weak detection signals. This reduces the influence of external noise and improves the signal-to-noise ratio.

[0044] 6. Forging machine 1 of the second embodiment Next, the differences between the second embodiment of the forging machine 1 and the first embodiment will be mainly explained with reference to Figures 8 and 9. In the second embodiment, the configuration of the wireless power supply unit 5A differs from that of the first embodiment, while other parts are the same as in the first embodiment. The wireless power supply unit 5A of the second embodiment consists of a magnet unit 5B, a power receiving unit 5D, and a power receiving circuit 5E, etc.

[0045] The magnet unit 5B is positioned on the frame 21 in place of the power supply unit 51 in the first embodiment. As shown in Figure 8, the magnet unit 5B is provided with three or more (eight in the example in Figure 8) permanent magnets 5C arranged so that the N and S poles of each permanent magnet 5C are alternating. By replacing the primary coil 52 of the first embodiment with permanent magnets 5C, the AC power supply 53 is not required in the second embodiment. It is also possible to use electromagnets instead of permanent magnets 5C, but an excitation power supply would be required.

[0046] The power receiving unit 5D is positioned on the ram 24 in place of the power receiving unit 55 of the first embodiment. As shown in Figure 8, the power receiving unit 5D has three secondary coils 56 arranged in the front-to-back direction of the ram 24. Similar to the first embodiment, the three secondary coils 56 move relative to each other in the front-to-back direction of the arrangement of the multiple permanent magnets 5C. At any position after relative movement, at least one of the secondary coils 56 faces the permanent magnet 5C, and an AC voltage is induced by electromagnetic induction.

[0047] The power receiving unit 5D is further accompanied by a power receiving circuit 5E, as shown in Figure 9. The power receiving circuit 5E is composed of three full-wave rectifier circuits 574, equal in number to the number of secondary coils 56, a capacitor 572, and a DC converter 575. The input side of the full-wave rectifier circuits 574 is connected to the windings of the secondary coils 56, and the output sides are connected in series with each other. Whether the three full-wave rectifier circuits (571, 574) are connected in parallel or in series is selected based on the magnitude of the voltage generated by the secondary coils 56, etc. The capacitor 572 is connected to the series connection of the three full-wave rectifier circuits 574. By using an electric double-layer capacitor, the capacitor 572 combines smoothing and power backup functions.

[0048] The DC converter 575 is connected across the capacitor 572. The DC converter 575 is a dual-output type that outputs two different voltage values. The DC converter 575 converts the DC power output by the full-wave rectifier circuit 574 to generate a first operating DC power and a second operating DC power. The first operating power is supplied to the non-contact transmission unit 4 via the power cable 58. The second operating power is supplied directly to the load cell 3 without passing through the non-contact transmission unit 4, and is supplied to the second detection unit 35 as needed.

[0049] Here, as shown in Figure 8, the multiple permanent magnets 5C are arranged in a line at a constant pitch distance D3. On the other hand, the three secondary coils 56 are arranged in a line at the same pitch distance D3 as the permanent magnets 5C. By setting the pitch distance D3 in this way, at a certain point in time, each of the three secondary coils 56 will link with the magnetic flux emanating from the N pole of the opposing permanent magnet 5C, or with the magnetic flux directed toward the S pole. At another point in time, each of the three secondary coils 56 will link with the magnetic flux emanating from the N pole of the permanent magnet 5C on the front side in the direction of travel and directed toward the S pole of the permanent magnet 5C on the rear side in the direction of travel. Furthermore, at yet another point in time, each of the three secondary coils 56 will link with the magnetic flux emanating from the N pole of the permanent magnet 5C on the rear side in the direction of travel and directed toward the S pole of the permanent magnet 5C on the front side in the direction of travel.

[0050] Therefore, the three secondary coils 56 efficiently induce an AC voltage through electromagnetic induction at any relative position. In other words, the wireless power supply unit 5A can provide stable contactless power supply performance no matter where the ram 24 moves. The wireless power supply unit 5A cannot provide contactless power supply during the time when the ram 24 is stopped, but this does not pose a problem as there is no need to detect the crushing force F. As a result, the power receiving circuit 5E can be configured without a storage battery (secondary battery). If, for example, only the N poles or only the S poles of the multiple permanent magnets 5C are arranged to face the secondary coils 56, the magnetic flux linking when the three secondary coils 56 are all located in the middle of the permanent magnets 5C decreases, and the induced AC voltage decreases. Other operations and effects in the second embodiment are the same as in the first embodiment, so their explanation is omitted.

[0051] 7. Modifications and Applications of Embodiments In the first and second embodiments, the detection unit is not limited to the load cell 3, but may be a temperature sensor that individually detects the temperature of the punch 26, for example, a three-wire resistance thermometer. Furthermore, the detection unit may be a displacement sensor or an AE sensor. The displacement sensor can detect the amount of displacement of the split punch 26 in the radial or axial direction during forging and can be used as an indicator for determining the status of the work. The AE sensor can detect elastic waves (acoustic emissions) generated in the punch 26 during forging and can be used as an indicator for determining the status of the work.

[0052] Furthermore, the wireless power supply unit (5, 5A) can be modified as appropriate. For example, a parallel connection of full-wave rectifier circuits 571 (see Figure 4) can be combined with a two-output DC converter 575 (see Figure 9). Also, the wireless power supply unit (5, 5A) may perform contactless power supply using a method different from the electromagnetic induction method, such as an electrostatic coupling method.

[0053] Furthermore, in the first embodiment, the load cell 3 can be provided on the side of the die 23, and the non-contact transmission unit 4 can be provided on the frame 21. In this embodiment, the wireless power supply unit 5 is equipped with a pair of primary coils 52 and secondary coils 56 that are positioned opposite each other without relative movement, thereby providing stable non-contact power supply performance. In this embodiment, when a failure occurs, the investigation of the cause by entering the narrow space inside the frame 21 can be simplified and made easier, enabling early recovery. In addition, wiring work during manufacturing and recovery work is greatly reduced. The present invention and its embodiments can be modified and applied in various ways other than those described above. [Industrial applicability]

[0054] The present invention and its embodiments can be widely used not only in the aforementioned forging machine 1, but also in machine tools that detect and monitor the current state or working status of a working part, and are particularly suitable for use in machine tools having a movable part that reciprocates in the front-rear direction relative to the frame. [Explanation of symbols]

[0055] 1: Forging machine 21: Frame 23: Die 24: Ram 26: Punch 3: Load cell 31: Signal cable 35: Second detection unit 4: Contactless transmission unit 5, 5A: Wireless power supply unit 51: Power supply unit 52: Primary coil 53: AC power supply 55, 5D: Power receiving unit 56: Secondary coil 57, 5E: Power receiving circuit 571, 574: Full-wave rectifier circuit 572: Capacitor 573, 575: DC converter 58: Power cable 5B: Magnet unit 5C: Permanent magnet 6: Receiver 8: Workpiece D1: Primary pitch distance D21, D22: Secondary pitch distance D3: Pitch distance MS: Radio signal

Claims

1. A workpiece implementation unit that performs a predetermined work, A detection unit that operates when power is supplied to it, detects a physical quantity representing the current state or working status of the workpiece, and outputs a detection signal. A non-contact transmission unit that operates when power is supplied and converts the detection signal into a transmission signal that can be transmitted without contact and sends it out, The system comprises a wireless power supply unit that supplies the operating power to the detection unit and the non-contact transmission unit in a non-contact manner, The aforementioned workpiece unit has a movable part that moves back and forth in the front-rear direction relative to the frame. The detection unit and the non-contact transmission unit are provided in the movable part. The wireless power supply unit is Multiple primary coils are arranged in the front-to-back direction of the frame, An AC power supply that supplies AC power to multiple primary coils, Multiple secondary coils are arranged in the front-rear direction of the movable part, and at least one of them faces the primary coil to receive the AC power in a non-contact manner when the movable part moves. The movable part includes a power receiving circuit that generates the operating power from the AC power received by a plurality of secondary coils, Three or more of the aforementioned primary coils are arranged in a line at a constant primary pitch distance, Three or more of the aforementioned secondary coils are arranged in a line with a non-constant secondary pitch distance. Machine tools.

2. The aforementioned power receiving circuit is Multiple full-wave rectifier circuits, each with an input side connected to each of the secondary coils and each with an output side connected to each other in parallel or in series, A capacitor connected to a parallel or series connection of multiple full-wave rectifier circuits, A DC converter connected to the capacitor, which converts the DC power output by the full-wave rectifier circuit to generate the DC operating power, and which does not have a storage battery, The machine tool according to claim 1.

3. The machine tool according to claim 1, wherein the non-contact transmission unit converts the detection signal into a wireless signal and transmits it.

4. The machine tool according to claim 3, further comprising a receiving unit that receives the aforementioned wireless signal and displays or records the aforementioned physical quantity.

5. Multiple types of detection units for detecting multiple types of the aforementioned physical quantities, The non-contact transmission unit is provided in common to multiple types of the detection unit, The wireless power supply unit is provided in common to multiple types of detection units and contactless transmission units, A machine tool according to claim 1, comprising:

6. The aforementioned work implementation unit is, A die provided on the frame to hold the workpiece, The system includes a punch provided on the movable part and moving together with the movable part, which, in combination with the die, performs a pressing process on the workpiece. The detection unit detects the physical quantity that represents the current state or working status of the punch. A machine tool according to any one of claims 1 to 5.

7. The aforementioned physical quantity is the forging force generated by the punch during the forging process. The non-contact transmission unit converts the detection signal of the pressing force into a wireless signal and transmits it. The machine tool according to claim 6.

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