JP7363739B2 - Piezoelectric actuator inspection equipment - Google Patents

Description

The present invention relates to a piezoelectric actuator inspection device for inspecting a piezoelectric actuator used to open and close a fuel injection valve called an injector, for example.

For example, in a fuel injection valve called an injector that injects fuel into the combustion chamber of an automobile engine, a piezoelectric actuator is used as a driving source for opening and closing the valve. This type of piezoelectric actuator includes a piezoelectric element that expands and contracts in the axial direction, a cylindrical case that houses the piezoelectric element, a driving member placed on the tip side of the piezoelectric element, and a terminal placed on the other end of the case. (For example, see Patent Document 1). This type of piezoelectric actuator is used in the harsh environment of an automobile engine, and after assembly, an inspection device performs a running-in operation called aging and a screening inspection, ie, a high-voltage debug inspection.

19 and 20 schematically show the configuration of a conventional inspection device 101 for inspecting the piezoelectric actuator 100. This inspection device 101 includes a batch-type heating furnace 102. A hot air generator including a heater and a blower is provided outside the heating furnace 102 , and hot air is supplied into the furnace from a hot air inlet 103 and discharged from an outlet 104 . A pallet mounting section 106 to which a pallet 105 is mounted is provided at the bottom of the heating furnace 102 . The pallet 105 has a square shape, and a large number of piezoelectric actuators 100 as workpieces are set in a grid pattern in front, back, left and right, with the drive member facing upward.

A pressing mechanism 107 for pressing the driving member of each of the piezoelectric actuators 100 from above is provided on the upper wall of the heating furnace 102, and a terminal of each of the piezoelectric actuators 100 is provided on the bottom of the heating furnace 102. An energizing probe 108 is provided which is connected to conducts energization and measurement. In the inspection apparatus 101, the pallet 105 is mounted in the heating furnace 102, and with each piezoelectric actuator 100 heated to a predetermined high temperature, the energized probe 108 is pressed while pressing each driving member by the pressing mechanism 107. By energizing the terminal from the terminal, the piezoelectric actuator 100 is run-in and debugged.

Japanese Patent Application Publication No. 2016-163390

However, in the conventional inspection apparatus 101 described above, a large number of piezoelectric actuators 100 are arranged in a grid in the heating furnace 102. Therefore, the hot air does not evenly hit each piezoelectric actuator 100, resulting in variations in the temperature of each piezoelectric actuator 100. As a result, it has been difficult to obtain the temperature conditions necessary for inspection, resulting in problems such as the inability to perform homogeneous and high-quality aging. In addition to the above, in the conventional inspection apparatus 101, the size of the pallet 105 is made relatively large in order to inspect a large number of piezoelectric actuators 100 at once, so the size of the heating furnace 102 and thus the overall size is large. However, there was still room for improvement in several aspects, such as the large thermal mass during heating, poor thermal efficiency, and long heating times.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a piezoelectric actuator inspection device that performs aging and screening inspections on a plurality of piezoelectric actuators, and is capable of performing inspections on a plurality of piezoelectric actuators in an evenly heated state. There is a particular thing.

In order to achieve the above object, a piezoelectric actuator inspection device (11, 71) houses a laminated piezoelectric element (3) in a cylindrical case (2), and has a drive member attached to one end of the case. (6) and a terminal (10) for energization on the other end side, the piezoelectric actuator (1) is heated to a predetermined temperature and the terminal is energized to expand and contract the piezoelectric element. Based on this, an aging and screening inspection is performed, and the inspection apparatus includes a pallet (13, 61) that holds a plurality of piezoelectric actuators side by side with the drive member side facing upward, and an inspection apparatus main body (12). The inspection device main body includes a batch type heating furnace (15, 62) in which the piezoelectric actuator held on the pallet is accommodated, and a hot air supply device (16) that supplies hot air to the heating furnace. a pressing mechanism (17) provided in the upper part of the heating furnace to press the driving member of each piezoelectric actuator with a predetermined load; and a pressing mechanism (17) provided in the lower part of the heating furnace connected to the terminal of each piezoelectric actuator and energized. and an energization measurement unit (18) that performs measurement, and the pallet is configured to hold a plurality of piezoelectric actuators in a line in the longitudinal direction or in two staggered rows in the longitudinal direction. The heating furnace is provided with a heating storage chamber (15a, 62a) that is horizontally elongated in the direction in which the piezoelectric actuators are arranged and has a size corresponding to the plurality of piezoelectric actuators. The side wall portion has an inlet portion (28, 63) for hot air from the hot air supply device and an outlet portion (29, 64) for the hot air.

In the above configuration, when performing aging and screening inspections, the plurality of piezoelectric actuators are housed in the heating accommodation chamber of the heating furnace while being held on the pallet. Then, the hot air supply device supplies hot air into the heating accommodation chamber to heat each piezoelectric actuator to a predetermined temperature. In this state, the pressing mechanism presses the driving member of each piezoelectric actuator with a predetermined load, and the energization measuring section conducts energization and measurement to the terminal of the piezoelectric actuator. As a result, aging and screening inspection of each piezoelectric actuator is performed.

At this time, the pallet that holds the plurality of piezoelectric actuators in the heating furnace has an elongated shape, and holds the piezoelectric actuators in one row or two staggered rows in the longitudinal direction. Thereby, the hot air supplied from the inlet can be directly applied to each piezoelectric actuator without being blocked by other piezoelectric actuators, making it possible to uniformly heat the piezoelectric actuators. Therefore, when performing aging and screening inspections on a plurality of piezoelectric actuators, an excellent effect can be obtained in that the inspection etc. can be performed with the plurality of piezoelectric actuators uniformly heated. Note that since the pallet has an elongated shape, the volume inside the heating storage chamber can be made relatively small, and the thermal mass during heating can be reduced, so that heating time can be shortened and thermal efficiency can be improved.

A front view schematically showing the overall configuration of the inspection device, showing the first embodiment. Front view of main parts showing the heating furnace in the lowered position Left side view schematically showing the overall configuration of the inspection device Plan view showing the configuration of the upper part of the hot air supply device Cross-sectional plan view of the area around the heating furnace of the inspection device Diagram schematically showing the configuration of the heating furnace and hot air supply mechanism of the inspection device Cross-sectional plan view of a heating furnace showing the arrangement of piezoelectric actuators Vertical front view of heating furnace Vertical side view of heating furnace Right side view showing the inlet of the heating furnace Left side view showing the outlet of the heating furnace Side view showing the configuration of the pressing mechanism part Front view schematically showing the configuration of the energization measurement section Flowchart showing inspection steps Vertical cross-sectional view showing the configuration of a piezoelectric actuator A cross-sectional plan view of a heating furnace showing the arrangement of piezoelectric actuators, showing the second embodiment. A plan view showing the third embodiment and schematically showing the overall configuration of the inspection device. Side view schematically showing the inspection device This shows a conventional example, and shows a schematic vertical cross-sectional view of the heating furnace section. Schematic plan view of the heating furnace section

(1) First Embodiment Hereinafter, a first embodiment applied to an inspection device for a piezoelectric actuator used as a drive source for a fuel injection valve called an injector installed in an automobile engine will be described below with reference to FIGS. 1 to 15. This will be explained with reference to. First, with reference to FIG. 15, the configuration of the piezoelectric actuator 1 in this embodiment will be briefly described.

The piezoelectric actuator 1 includes a cylindrical case 2 and three stacked piezoelectric elements. The piezoelectric element 3 is constructed by alternately laminating piezoelectric layers 4 made of piezoelectric ceramics and internal electrode layers 5. A drive member 6 that is driven by the expansion and contraction of the piezoelectric element 3 is provided at the tip of the case 2, that is, at the upper end in the figure, via a metal diaphragm 7. Inside the case 2, a pair of left and right side electrodes 8, 8 are provided in the figure, one side electrode 8 is connected to every other internal electrode layer 5, and the other side electrode 8 is connected to every other layer. It is connected to the internal electrode layer 5. A housing 9 is provided at the other end of the case 2, that is, the lower end in the figure, and the housing 9 is provided with a pair of current-carrying terminals 10, 10 connected to the side electrodes 8, 8, respectively. There is.

Next, an inspection apparatus 11 according to the present embodiment for performing the aging and screening inspection of the piezoelectric actuator 1 described above will be described. In the following explanation, when referring to front, rear, left, and right directions, for convenience, the longitudinal direction of the heating furnace is referred to as the front and rear direction, and the side where the hot air inlet of the heating furnace is located is the right side, and the hot air is referred to as the right side. The side with the exit section will be described as the left side. 1 to 6 show the overall configuration of the inspection device 11. FIG. This inspection device 11 includes an inspection device body 12 provided on the floor of the facility, and a pallet 13 that is inserted into and taken out from the inspection device body 12 while holding a plurality of the piezoelectric actuators 1.

As shown in FIG. 7, the pallet 13 has a rectangular plate shape that is slightly elongated in the front-rear direction in the figure, and holds the piezoelectric actuator 1 in an upright state, as shown in FIGS. 8, 9, and 13. A plurality of pallet jigs 14, for example, ten pallet jigs 14, are provided for this purpose. The pallet jigs 14 are arranged in two staggered rows in the longitudinal direction of the pallet 13, that is, in the front-back direction, and the piezoelectric actuator 1 is inserted from above to hold the lower end thereof. In this way, as shown in FIGS. 5 and 7, a plurality of piezoelectric actuators 1, for example, ten piezoelectric actuators 1, are held in two staggered rows on the pallet 13.

Further, as shown in FIG. 13, the pallet jig 14 is provided so as to vertically penetrate the pallet 13, and a connection hole 14a that expands downward is formed on the lower surface side of the pallet jig 14. The lower end of the piezoelectric actuator 1 is disposed in the hole 14a, and the lower end of the terminal 10 is connected to an energization probe of an energization measuring section, which will be described later. Although not shown in detail, the pallet 13 is also provided with positioning pin insertion holes, which will be described later, at key locations.

As shown in FIG. 6 etc., the inspection device main body 12 is roughly divided into a batch-type heating furnace 15 in which a plurality of piezoelectric actuators 1 held on the pallet 13 are accommodated, and a batch-type heating furnace 15 in which a plurality of piezoelectric actuators 1 held on the pallet 13 are accommodated. a hot air supply device 16 for supplying hot air; a pressing mechanism 17 provided at the upper part of the heating furnace 15 for pressing the drive member 6 of each piezoelectric actuator 1 with a predetermined load; An energization measurement unit 18 connected to the terminal 10 of each piezoelectric actuator 1 to conduct energization and measurement, a transport unit 19 that transports the pallet 13 to the heating furnace 15, and a computer that controls the whole and performs inspection. It includes a control device consisting of etc. Hereinafter, the configuration of each of these parts will be explained in order.

The heating furnace 15 will be described with reference also to FIGS. 6 to 12. As shown in FIGS. 6 to 9, the heating furnace 15 is made of a heat insulating material and has a rectangular box shape that is slightly elongated in the front and back direction, and includes a bottom wall 20, front and rear walls 21 and 22, and left and right side walls. parts 23 and 24, and a ceiling wall part 25. The inside of this heating furnace 15 is a heating accommodation chamber 15a in which the piezoelectric actuator 1 is accommodated. The heating accommodation chamber 15a is configured to have a volume as small as possible, which is sufficient to accommodate the plurality of piezoelectric actuators 1 held on the pallet 13.

The heating furnace 15 is provided so as to be movable up and down with respect to the inspection apparatus main body 12, that is, the floor of the equipment, and is moved to the raised position shown in FIGS. 1 and 3 and the raised position shown in FIG. It is adapted to be moved between the lowered position and the lowered position. As shown in FIGS. 8, 13, etc., the bottom wall 20 of the heating furnace 15 is provided with through holes 20a through which the plurality of piezoelectric actuators 1 held on the pallet 13 are inserted. As shown in FIGS. 1 and 3, a pallet loading section 27 into which the pallet 13 is loaded is provided in the lower part of the heating furnace 15. As shown in FIGS. The conveyance section 19 conveys the pallet 13 between the workpiece setting position, which is located outside the lower part of the heating furnace 15 and where the piezoelectric actuator 1 is set and removed, and the pallet loading section 27. It is configured as follows.

In this way, as shown in FIGS. 1 and 3, the pallet 13 holding the plurality of piezoelectric actuators 1 is carried into the pallet loading section 27 by the conveyance section 19 at the elevated position of the heating furnace 15. Then, as the heating furnace 15 is lowered from the raised position to the lowered position shown in FIG. The heating storage chamber 15a is placed inside the heating accommodation chamber 15a. As shown in FIGS. 8 and 9, when the heating furnace 15 is in the lowered position, the pallet 13 is placed directly below the heating furnace 15. In this lowered position of the heating furnace 15, aging and screening inspections are performed.

As shown in FIGS. 5 to 10, an inlet portion 28 of hot air from a hot air supply device 16, which will be described later, is provided in the right side wall portion 24 of the heating furnace 15 in a horizontally long rectangular shape. Further, as shown in FIG. 11, a hot air outlet portion 29 is similarly provided in a horizontally long rectangular shape on the left side wall portion 23 opposite to the right side wall portion 24. As shown in FIG. As shown in FIG. 8, a hot air flow path is formed in the heating storage chamber 15a from the inlet portion 28 to the outlet portion 29. It is placed at a height that allows you to hit it.

In this embodiment, as shown in FIGS. 5 and 7, the heating furnace 15 includes rectifying plates 30 and 31 for guiding hot air toward the case 2 of each piezoelectric actuator 1 in the hot air flow path. is provided. In FIG. 7, only a part of the current plates 30 and 31 is shown, and illustration of the whole is omitted. Among them, the rectifying plate 30 on the inlet portion 28 side is provided so as to guide the hot air introduced from the inlet portion 28 toward each piezoelectric actuator 1 . In this case, the current plates 30 and 31 directly guide the hot air from the inlet 28 toward all the piezoelectric actuators 1, and the hot air that has passed through the piezoelectric actuators 1 in the right row is further directed to the piezoelectric actuators 1 in the left row. Guide toward actuator 1. Further, it is provided so as to guide the hot air that has passed through the left piezoelectric actuator 1 toward the outlet portion 29 .

Furthermore, in this embodiment, as shown in FIG. 10, an adjustment plate 32 for adjusting the flow rate of hot air is provided at the entrance portion 28 of the heating storage chamber 15a of the heating furnace 15 for each piezoelectric actuator 1. ing. These adjustment plates 32 are provided so that their positions can be individually adjusted up and down, and are configured to adjust the opening area of each flow path for the hot air flow path for each piezoelectric actuator 1 formed by the rectifying plate 30. ing. Further, in this embodiment, as shown in FIG. 11, a partition plate 29a is provided at the outlet part 29 of the heating accommodation chamber 15a so as to close the lower half, and five outlet side adjustment plates 33 are provided. They are individually adjustable up and down. These baffle plates 31 are configured so that the opening area of the hot air flow path in the outlet section 29 can be adjusted.

Next, a description will be given of the hot air supply device 16 for supplying, in this case circulating, hot air to the heating furnace 15. In this embodiment, as shown in FIGS. 2 to 4, 6, etc., the hot air supply device 16 has a circulating system that connects the inlet section 28 and outlet section 29 of the hot air of the heating furnace 15 on the outside of the heating furnace 15. It includes an air passage 34 and a heater 35 and a blower 36 provided in the middle of the circulation air passage 34. At this time, the heater 35 and the blower 36 are arranged above the heating furnace 15. It should be noted that the heater 35 is a unit made by disposing, for example, a small electric heater of 200° C. or less in a duct. As shown in FIG. 4, the blower 36 includes a centrifugal fan (not shown) inside a casing 36a, and a motor 36b for rotationally driving the fan, so that the flow rate of hot air can be controlled by inverter control.

As schematically shown in FIG. 6, the circulation air passage 34 includes, in order from the outlet 29 side of the heating furnace 15, an outlet side duct hood 37, an outlet side connection pipe 38, an outlet pipe 39, the blower 36, and the It includes a heater 35, an inlet pipe 40, an inlet side connecting pipe 41, and an inlet side duct hood 42, and circulates hot air in the direction of arrow A. At this time, although not shown in detail, the outlet piping 39, the blower 36, the heater 35, and the inlet piping 40 are connected to an equipment mount 43 fixedly provided on the upper part of the equipment, as shown in FIGS. 2, 3, etc. installed on. Further, the outlet side duct hood 37, the outlet side connecting pipe 38, the inlet side connecting pipe 41, and the inlet side duct hood 42 are attached to the heating furnace 15 and are designed to move up and down integrally with the heating furnace 15. ing.

As shown in FIG. 5, the outlet-side duct hood 37 and the inlet-side duct hood 42 have a pentagonal top surface, and the openings on the sides cover the left and right sides of the heating furnace 15 so as to close the inlet part 28 and the outlet part 29. Attached to the outside wall. Also, inside the outlet side duct hood 37 and the inlet side duct hood 42, as shown in FIGS. 2 and 8, a guide plate 37a and a 42a are provided respectively.

As shown in FIGS. 3 and 5, a lower end portion of the outlet connecting pipe 38 is fixedly connected to a left-side portion of the rear surface of the outlet duct hood 37. As shown in FIGS. As shown in FIG. 3, the outlet side connection pipe 38 extends backward by a slight amount from the rear surface of the outlet side duct hood 37, and then curves at 90 degrees and extends upward. As shown in FIGS. 1 and 2, the upper end of the outlet side connection pipe 38 is slidably fitted from below to the inner circumferential surface of the lower end of the outlet pipe 39. While maintaining their fitted state, the heating furnace 15 can be moved in the vertical direction between the raised position and the lowered position.

The outlet pipe 39 extends upward from the rear left side of the heating furnace 15, and as shown in FIG. It curves 90 degrees and extends to the right. The right end of the outlet pipe 39 is connected to the suction port on the left side wall of the casing 36a of the blower 36, and the discharge port of the blower 36 extending rearward is connected to the inlet of the heater 35 at the front. . The outlet of the heater 35 opens rearward, and the proximal end of the inlet pipe 40 is connected to its tip. The inlet pipe 40 extends a certain distance rearward from the outlet of the heater 35, then bends 90 degrees while curving, and extends downward through the right rear part of the heating furnace 15.

As shown in FIG. 5, the lower end portion of the inlet side connecting pipe 41 is fixedly connected to the right side portion of the rear surface of the inlet side duct hood 42. As shown in FIG. The inlet side connection pipe 41 extends backward by a slight amount from the rear surface of the inlet side duct hood 42, and then curves at 90 degrees and extends upward. As shown in FIG. 2, the upper end of the inlet side connecting pipe 41 is slidably fitted from below to the outer circumferential surface of the lower end of the inlet pipe 40. The heating furnace 15 can be moved in the vertical direction between the raised position and the lowered position while maintaining the state.

In the hot air supply device 16 configured in this manner, the blower 36 and the heater 35 are driven to circulate and supply hot air as shown by the arrow A in FIG. 6 and the like. That is, by driving the blower 36, the hot air in the heating furnace 15 is discharged from the outlet section 29, passes through the outlet side duct hood 37, the outlet side connecting pipe 38, and the outlet pipe 39 in this order, and is sucked into the blower 36. The air discharged from the blower 36 is heated by the heater 35, passes through the inlet pipe 40, the inlet side connection pipe 41, and the inlet side duct hood 42 in this order, and is supplied into the heating furnace 15 from the inlet section 28. At this time, during inspection, hot air controlled at, for example, 130 to 145° C. is circulated and supplied into the heating furnace 15 at a required flow rate.

As shown in FIG. 3, the circulating air passage 34, the heater 35, and the blower 36 of the hot air supply device 16 are arranged together with the heating furnace 15 in a U-shape with an open front when viewed from the side. A maintenance area for the pressing mechanism 17, heating furnace 15, energization measurement section 18, conveyance section 19, lifting mechanism 26, etc. is secured. In addition, as shown in FIG. 4, the circulation air passage 34 is provided in a U-shape that opens rearward when viewed from above, and is used for the motor portions of the lifting mechanism 26 and the pressing mechanism 17, which will be described below. A maintenance area has been secured.

Next, the pressing mechanism 17 and the lifting mechanism 26 will be described with reference to FIG. 12 as well. The lifting mechanism 26 moves the heating furnace 15 and the pressing mechanism 17 up and down integrally with respect to the equipment, and is configured as follows. That is, as shown in FIGS. 1 to 3, the equipment frame 43 is provided with a plurality of guide bars 44 extending downward, and the mounting base 45 is moved in the vertical direction along these guide bars 44. Possibly supported. As shown in FIG. 12, a lid plate 47 of the ceiling wall portion 25 of the heating furnace 15 is connected to the mounting base 45 via a connecting member 46. As shown in FIG. As shown in FIG. 1 and the like, the equipment pedestal 43 is provided with a drive motor 48 and a transmission mechanism 49 for moving the mounting base 45 up and down. Although detailed description will be omitted, the transmission mechanism 49 includes a belt transmission mechanism using a pulley, a ball screw/nut mechanism, and the like.

Along with this, the pressing mechanism 17 is assembled to the mounting base 45. The pressing mechanism 17 includes a plurality of pressing members 50 (ten in this case) extending downward from the mounting base 45 in a bar shape. Each pressing member 50 is configured to be moved up and down between a pressurizing position and a pressurizing release position by a pressurizing cylinder 51, and to be able to apply a predetermined downward pressing force by a spring 56. . At this time, as shown in FIG. 12 etc., the ceiling wall 25 and the lid plate 47 of the heating furnace 15 are located at positions corresponding to the through holes 20a of the bottom wall 20, that is, the positions held by the pallet 13. A through hole 25 a is provided above each piezoelectric actuator 1 . The lower ends of each of the pressing members 50 are positioned in the heating storage chamber 15a of the heating furnace 15 through the through hole 25a.

With this, the pressing mechanism 17 moves each pressing member 50 to the heating furnace 15 by moving the heating furnace 15 to the lowered position with the pallet 13 holding the piezoelectric actuator 1 set in the pallet loading section 27. It is located on the top of each piezoelectric actuator 1 within. In this state, each pressing member 50 is lowered to the pressing position by the pressing cylinder 51, thereby pressing each driving member 6 from above with a predetermined load. The load with which the spring 56 presses the drive member 6 at this time can be adjusted for each pressing member 50.

As shown in FIG. 13 etc., the energization measurement section 18 is configured by holding a plurality of energization probes 52 (in this case ten pairs) connected to each terminal 10 of the piezoelectric actuator 1 by a probe holder 53. . At this time, as shown in FIG. 13, a plurality of holding members 54 are provided on the upper surface of the probe holder 53, to which each energizing probe 52 is attached in a detachable and position-adjustable manner. As shown in FIG. 1, the probe holder 53 is provided so as to be able to be taken in and out of the pallet loading section 27, and has a use position located at the bottom of the pallet 13 and a use position where it is pulled out to the left in the figure and removed from the heating furnace 15. It is configured to move to and from a ready position. Further, as shown in FIG. 13 and the like, a lifting cylinder 55 is provided at the bottom of the probe holder 53, and is configured to be lifted up and down from the floor of the equipment.

With this, the operator performs work such as position adjustment and replacement of the energizing probes 52 in each holding member 54 at the preparation position of the probe holder 53 pulled out from the lower part of the heating furnace 15 . Then, with the probe holder 53 moved to the use position, the probe holder 53 is raised by the lifting cylinder 55. As a result, the upper end of each energizing probe 52 held by the holding member 54 is inserted into the connection hole 14a of the pallet jig 14 on the lower surface of the pallet 13 and electrically connected to the terminal 10. At this time, the holding member 54 also serves to guide the upper end of the energizing probe 52 into the hole 14a.

Although illustrations and detailed explanations are omitted, the conveyance section 19 includes a robot, and the piezoelectric actuators 1 are set one by one on the pallet jig 14 at the work setting position of the pallet 13 by the robot. As shown in FIG. 1, the workpiece setting position is provided, for example, on the right side of the heating furnace 15. After setting, the pallet 13 holding the piezoelectric actuator 1 is transported to the pallet loading section 27 by a loader at the elevated position of the heating furnace 15. In the pallet loading section 27, positioning pins are inserted into pin insertion holes to position the pallet 13 relative to the heating furnace 15. After the inspection is completed, the pallet 13 is transported by the loader to the workpiece setting position with the heating furnace 15 moved to the raised position.

Next, the aging and screening inspection of the piezoelectric actuator 1 performed in the inspection apparatus 11 having the above configuration will be described with reference to FIG. 14 as well. FIG. 14 shows the aging and screening test procedure. In FIG. 14, the piezoelectric actuator 1 is described as a workpiece. Before conducting the inspection, as a preparatory work, as described above, the energized probe 52 is set in the probe holder 53, and the probe holder 53 is moved to the use position below the heating furnace 15.

In FIG. 14, when an inspection is started, first in step S1, a plurality of piezoelectric actuators 1 are set on a pallet 13 at a workpiece setting position. This setting operation is performed by placing each piezoelectric actuator 1 with the terminal 10 side facing downward and inserting its lower end into each pallet jig 14 from above. In this way, as shown in FIGS. 5 and 7, a plurality of piezoelectric actuators 1 are held in two staggered rows on the pallet 13.

When the setting work of the piezoelectric actuator 1 on the pallet 13 is completed (Yes in step S1), in the next step S2, the pallet 13 is moved to the lower part of the heating furnace 15 by a loader with the heating furnace 15 in the raised position. The pallet is transported to the pallet loading section 27. In step S3, in the pallet loading section 27, the positioning pin is raised and inserted into the positioning hole of the pallet 13, and the pallet 13 is positioned and fixed.

In the next step S4, the heating furnace 15 is lowered to the lowered position by the lifting mechanism 26, and the hot air supply device 16 is driven. As the heating furnace 15 is lowered, as shown in FIG. , are arranged in the heating accommodation chamber 15a. At this time, the hot air flow path in the heating accommodation chamber 15a is provided so that the hot air hits the case 2 of each piezoelectric actuator 1. Furthermore, as shown in FIG. 9, in the lowered position of the heating furnace 15, the pallet 13 is placed directly below the bottom wall portion 20.

In step S5, as shown in FIG. 13, in the energization measuring section 18, the probe holder 53 and eventually the energizing probe 52 are raised by the lifting cylinder 55 and electrically connected to each terminal 10 of each piezoelectric actuator 1. In step S6, as shown in FIGS. 8 and 9, in the pressing mechanism 17, each pressing member 50 is lowered to the pressing position by the pressing cylinder 51, so that the driving member 6 of each piezoelectric actuator 1 is moved from above. It comes to be pressed with a predetermined load.

Here, in step S4, the blower 36 and heater 35 of the hot air supply device 16 are started to be driven, so that hot air controlled at, for example, 130 to 145° C. is supplied as shown by arrow A in FIGS. 5, 6, etc. , and are circulated and supplied into the heating furnace 15 at a required flow rate through the circulation air passage 34. This hot air heats the piezoelectric actuator 1 placed in the heating furnace 15. At this time, as shown in FIGS. 5 and 7, rectifier plates 30 and 31 are provided on the inlet 28 side and the outlet 29 side of the heating furnace 15, respectively, so that the hot air can be efficiently directed to each piezoelectric actuator 1. Moreover, it can be supplied uniformly. Furthermore, as shown in FIGS. 10 and 11, an adjustment plate 32 is provided at the inlet portion 28, and an outlet-side adjustment plate 33 is provided at the outlet portion 29 to adjust the flow rate of hot air for each piezoelectric actuator 1. It is also possible to do so.

Returning to FIG. 14, in step S7, continuity between the terminals 10 of each piezoelectric actuator 1 is checked using the energization probe 52. Note that if an abnormality such as a short circuit is determined in this continuity check, the probe holder 53 is lowered once, the position of the energizing probe 52 is adjusted as necessary, and then a retry operation is executed. If there is no abnormality in the continuity check, in the next step S8, the probe 52 performs an energizing operation, and a first run-in operation is performed for a certain period of time, for example, about several tens of seconds. In this first run-in operation, the terminal 10 is alternately and repeatedly energized with a voltage of, for example, 0V to 135V.

When the first run-in operation is completed, the power supply to the terminal 10 is stopped, and in step S9, each pressing member 50 of the pressing mechanism 17 is raised, and the pressure applied to the drive member 6 of each piezoelectric actuator 1 is temporarily released. Ru. After a certain period of time has elapsed, in step S10, each pressing member 50 of the pressing mechanism 17 is lowered to apply pressure again to the drive member 6 of each piezoelectric actuator 1. Subsequently, in step S11, energization by the probe 52 is started, and a second familiarization operation is performed. This second run-in operation is also performed by alternately repeating energizing the terminal 10 with a voltage of, for example, 0V to 135V, and is executed for a relatively long time, for example, about 7 to 8 minutes. Thus, so-called aging of the piezoelectric element 3 is performed, and the piezoelectric actuator 1 becomes ready for use.

When the second familiarization operation is completed, a screening test, that is, a high voltage debug test is executed in step S12. This screening test is performed by applying a DC voltage of, for example, 148 V between the terminals 10 of each piezoelectric actuator 1 by the current measurement unit 18, measuring the insulation resistance value, and determining abnormality. When the screening test is completed, in step S13, each pressing member 50 of the pressing mechanism 17 is raised to release the pressure on the drive member 6 of each piezoelectric actuator 1, and the heating by the hot air supply device 16 is stopped. Ru.

Then, in step S14, the probe holder 53 and eventually the energization probe 52 are lowered by the lifting cylinder 55 of the energization measuring section 18, and the connection between each piezoelectric actuator 1 and each terminal 10 is severed. In step S15, the heating furnace 15 is raised to the raised position by the lifting mechanism 26, and in step S16, the positioning pin of the pallet loading section 27 is lowered to release the fixation of the pallet 13. In step S17, the pallet 13 is carried out to the workpiece setting position, the piezoelectric actuator 1 is taken out from the pallet 13, and the inspection is completed.

According to the inspection device 11 of such an embodiment, the following effects can be obtained. That is, the pallet 13 that holds the plurality of piezoelectric actuators 1 in the heating furnace 15 has an elongated shape, and is configured to hold the piezoelectric actuators 1 in two staggered rows in the longitudinal direction. As a result, the hot air supplied from the inlet 28 of the heating furnace 15 can be directly applied to each piezoelectric actuator 1 without being blocked by other piezoelectric actuators 1, thereby heating the piezoelectric actuator 1 uniformly and efficiently. becomes possible. Therefore, when performing aging and screening inspections on a plurality of piezoelectric actuators 1, an excellent effect can be obtained in that the inspection etc. can be performed while the plurality of piezoelectric actuators 1 are uniformly heated.

At this time, since the pallet 13 has an elongated shape that is long from front to back as shown in the figure, the volume inside the heating storage chamber 15a can be made relatively small, and the thermal mass during heating can be made small, thereby shortening the heating time. It is possible to improve thermal efficiency. Further, the hot air flow path in the heating accommodation chamber 15a of the heating furnace 15 is configured to supply hot air to the case 2 portion of each piezoelectric actuator 1. According to this, the hot air is configured to pass through only the areas necessary for inspection of the piezoelectric actuator in the heating accommodation chamber 15a, and the volume of the heating accommodation chamber 15a can be further reduced to improve thermal efficiency.

In this embodiment, since the rectifier plates 30 and 31 are provided on the inlet section 28 side and the outlet section 29 side of the heating furnace 15, respectively, hot air can be applied to each piezoelectric actuator 1 more evenly. Therefore, the effect of uniformly heating the plurality of piezoelectric actuators 1 is excellent. In this embodiment, an adjustment plate 32 for adjusting the flow rate of hot air is provided for each piezoelectric actuator 1 at the entrance part 28 of the heating storage chamber 15a, and an outlet side adjustment plate 32 is also provided at the outlet part 29. 33 are provided. These adjustment plates 32 and 33 make it possible to adjust the flow rate of hot air for each piezoelectric actuator 1, making it possible to more precisely adjust the heating state of each piezoelectric actuator 1, and achieving more even heating. can.

Further, in this embodiment, the hot air supply device 16 includes a circulating air passage 34 and a heater 35 and a blower 36 provided in the middle of the circulating air passage 34, and the heater 35 and the blower 36 are installed in the upper part of the heating furnace 15. The configuration was such that the Thereby, energy efficiency can be improved by providing a configuration in which hot air is supplied through the circulation air path 34. Moreover, by arranging the heater 35 and the blower 36 at the upper part of the heating furnace 15, it becomes possible to arrange the inspection apparatus main body 12 in a compact manner as a whole. In addition, since the circulating air passage 34, heater 35, and blower 36 are arranged with a maintenance space secured for the pressing mechanism 17, maintenance of the pressing mechanism 17, etc. can be easily performed while maintaining a compact overall arrangement. It can be carried out.

In particular, in this embodiment, the pressing mechanism 17 includes a pressing member 50 for each piezoelectric actuator 1 vertically penetrating the ceiling wall 25 of the heating furnace 15, and each pressing member 50 is a driving member for each piezoelectric actuator 1. 6 was configured to be pressed with a predetermined load. This makes it possible to prevent the entire pressing member 50 from being exposed to high temperatures while ensuring the necessary functions of the pressing mechanism 17, so the pressing mechanism 17 as a whole does not need to have a very strict heat-resistant structure. .

In the present embodiment, the energization measurement section 18 is configured such that a plurality of energization probes 52 corresponding to the terminals 10 of each piezoelectric actuator 1 are detachably attached to the probe holder 53 and whose positions are adjustable. Further, the probe holder 53 is configured to move between a use position located at the lower part of the pallet 13 and a preparation position where it is pulled out from the lower part of the heating furnace 15. Here, in order to ensure the connection between the energizing probes 52 and the terminals 10, it is necessary to align each energizing probe 52, and the energizing probes 52 are replaced relatively frequently due to damage or the like. . With the above configuration, it is possible to easily adjust the position of each energizing probe 52, replace it, etc. with the probe holder 53 pulled out to the ready position.

(2) Second Embodiment FIG. 16 shows a second embodiment. This second embodiment differs from the first embodiment described above in the configuration of the pallet 61 and the associated configuration of the heating furnace 62. That is, in the second embodiment, the pallet 61 is configured to hold a plurality of piezoelectric actuators 1, for example, ten piezoelectric actuators 1 in a line in the longitudinal direction. In this case, the pallet 61 is elongated in the front-rear direction in the figure, and although not shown, the pallet 61 is provided with a plurality of, for example, ten, pallet jigs 14 for holding the piezoelectric actuator 1 in an upright state. It is being

The heating furnace 62 is elongated in the front-rear direction corresponding to the pallet 61, and includes a heating chamber 62a having a size or height corresponding to the case 2 of the piezoelectric actuator 1 held on the pallet 61. A hot air inlet 63 is provided on the opposite sidewalls on the longer sides of the heating furnace 62, that is, the right sidewall in the figure, and a hot air outlet 64 is provided on the left sidewall in the figure. The inlet section 63 and the outlet section 64 are connected to the hot air supply device 16. Further, in this embodiment, as only a portion is shown, the heating furnace 62 includes a rectifier that guides the hot air introduced from the inlet section 63 toward each piezoelectric actuator 1 and then toward the outlet section 64. Plates 65 and 66 are provided.

Also according to the second embodiment, the hot air supplied from the inlet portion 63 of the heating furnace 62 can be directly applied to each piezoelectric actuator 1 without being blocked by other piezoelectric actuators 1. , it becomes possible to heat uniformly. Therefore, when performing aging and screening inspections on a plurality of piezoelectric actuators 1, an excellent effect can be obtained in that the inspection etc. can be performed while the plurality of piezoelectric actuators 1 are uniformly heated. By providing the rectifying plates 65 and 66, the effect of uniformly heating the plurality of piezoelectric actuators 1 is improved. Furthermore, since the pallet 61 has an elongated shape, the volume inside the heating accommodation chamber 62a can be made relatively small, and the thermal mass during heating can be reduced, thereby shortening the heating time and improving thermal efficiency. I can do it.

(3) Third Embodiment and Other Embodiments FIGS. 17 and 18 show a third embodiment. The inspection device 71 according to the third embodiment includes not only one inspection device main body 12 as described in the first embodiment but also a plurality of inspection device main bodies 12 on the floor of the equipment. In this case, one inspection device main body 12 is used as a unit, and six units are arranged in two rows on the left and right and three rows on the front and back, with a passage 72 extending in the front-rear direction in the center. Each inspection device main body 12 is installed such that the work setting position of the pallet 13 is located on the passage 72 side.

At this time, in each inspection device main body portion 12, a soundproofing material 73 is provided so as to cover the periphery of the heating furnace 15. This soundproofing material 73 is provided so as to surround four sides of each inspection apparatus main body 12 except for the upper surface and the side surface on the passage 72 side, that is, on the work setting position side of the pallet 13. In this case, the soundproofing material 73 is provided at a location where vibration noise that is harmful to humans is generated, that is, at a height position surrounding the drive member 6 portion of the piezoelectric actuator 1 and the pressing member 50 portion of the pressing mechanism 17. .

A heat-insulating overall safety cover 74 is provided so as to entirely surround the six inspection device main bodies 12. As shown in FIG. 17, this overall safety cover 74 encloses the whole in a square shape when viewed from the top, and is provided so that the top surface covers up to the height of the upper part of the equipment pedestal 43, as shown in FIG. Furthermore, on the ceiling of the overall safety cover 74, a chimney-shaped cover 75 is located above each inspection device main body 12 and has an open top and bottom for discharging heat from each inspection device main body 12. It is arranged in a rectangular tube shape.

According to the third embodiment, aging and screening tests can be efficiently performed on a large number of piezoelectric actuators 1 at once by arranging a plurality of unitized inspection device main bodies 12, for example, six pieces. becomes possible. At the same time, the high-temperature area caused by the heating furnace 15 is isolated by the overall safety cover 74, so that the safety of workers and the like can be ensured. By providing the chimney-like cover 75 on the ceiling of the overall safety cover 74, the heat from the inspection device body 12 can be further discharged, making it more effective. Since the soundproofing material 73 is provided to cover the periphery of the heating furnace 15, vibration noise generated by the drive member 6, pressing mechanism 17, etc., does not leak to the outside of the inspection device main body 12 during inspection. can be suppressed.

In the above embodiment, the present invention is applied to the inspection of the piezoelectric actuator 1 used as a drive source of a fuel injection valve, but the present invention is applicable to inspection devices for piezoelectric actuators for various purposes. The shape and structure of the heating furnace, the configuration of the hot air supply device, the configuration of the pressing mechanism, the energization measuring section, etc. can also be modified in various ways. Furthermore, examples of specific numerical values, such as the number of piezoelectric actuators held by a pallet, the time, voltage, temperature of hot air, and the number of inspection apparatus bodies to be combined in aging and screening inspections explained in the above embodiment, will be given below. These are just the examples listed above, and it goes without saying that they can be implemented with appropriate modifications.

In addition, the outlet side adjusting plate 33, soundproof material 73, chimney-shaped cover 75, etc. may be provided as necessary. Although the present disclosure has been described based on examples, it is understood that the present disclosure is not limited to the examples or structures. The present disclosure also includes various modifications and equivalent modifications. In addition, various combinations and configurations, as well as other combinations and configurations that include only one, more, or fewer elements, are within the scope and scope of the present disclosure.

In the drawings, 1 is a piezoelectric actuator, 2 is a case, 3 is a piezoelectric element, 6 is a driving member, 10 is a terminal, 11 and 71 are inspection devices, 12 is an inspection device main body, 13 and 61 are pallets, and 14 is a pallet cure. 15 and 62 are heating furnaces, 16 are hot air supply devices, 17 are pressing mechanisms, 18 are energization measurement units, 19 are conveyance units, 20 are bottom wall units, 25 are ceiling wall units, 26 are lifting mechanisms, and 27 are 28, 63 are inlet parts, 29, 64 are outlet parts, 30, 31, 65, 66 are rectifying plates, 32 is an adjusting plate, 34 is a circulation air passage, 35 is a heater, 36 is a blower, 43 is a pallet loading part; Equipment frame, 45 is a mounting base, 50 is a pressing member, 51 is a pressurizing cylinder, 52 is an energizing probe, 53 is a probe holder, 55 is a lifting cylinder, 73 is a soundproofing material, 74 is a safety cover, 75 is a chimney-shaped cover shows.

Claims (11)

A laminated piezoelectric element (3) is housed in a cylindrical case (2), a driving member (6) is provided at one end of the case, and a terminal (10) for energization is provided at the other end. A piezoelectric actuator inspection device (11, 71) that performs an aging and screening inspection on the piezoelectric actuator (1), which is heated to a predetermined temperature, and conducts an aging and screening inspection by applying electricity to the terminal to expand and contract the piezoelectric element. ) and
It includes a pallet (13, 61) that holds a plurality of piezoelectric actuators side by side with the drive member side facing upward, and an inspection device main body (12),
The inspection device main body part is
a batch-type heating furnace (15, 62) in which the piezoelectric actuator held on the pallet is housed;
a hot air supply device (16) that supplies hot air to the heating furnace;
a pressing mechanism (17) provided at the upper part of the heating furnace and pressing the drive member of each piezoelectric actuator with a predetermined load;
an energization measurement unit (18) provided below the heating furnace and connected to a terminal of each piezoelectric actuator to conduct energization and measurement;
The pallet is configured to hold a plurality of piezoelectric actuators in a line in the longitudinal direction, or in two staggered rows in the longitudinal direction,
The heating furnace includes a heating storage chamber (15a, 62a) that is horizontally elongated in the direction in which the piezoelectric actuators are arranged and has a size corresponding to the plurality of piezoelectric actuators, and has opposite side walls on the long sides of the heating storage chamber. A piezoelectric actuator inspection device having an inlet section (28, 63) for hot air from the hot air supply device and an outlet section (29, 64) for hot air from the hot air supply device. The piezoelectric actuator inspection device according to claim 1, wherein the heating furnace is provided with a rectifying plate (30, 31, 65, 66) for guiding hot air toward each of the piezoelectric actuators. 3. The piezoelectric actuator inspection apparatus according to claim 1, wherein the hot air flow path in the heating accommodation chamber is configured to supply hot air to a case portion of each of the piezoelectric actuators. The piezoelectric actuator according to any one of claims 1 to 3, wherein an adjustment plate (32) for adjusting the flow rate of hot air is provided for each of the piezoelectric actuators at the entrance of the heating storage chamber. inspection equipment. The hot air supply device includes a circulating air path (34) that connects the hot air inlet and outlet outside the heating furnace, and a heater (35) and a blower (36) provided in the middle of the circulating air path. ), wherein the heater and the blower are disposed above the heating furnace. 6. The piezoelectric actuator inspection device according to claim 5, wherein the circulating air path, the heater, and the blower are arranged with a maintenance space secured for the pressing mechanism. The pressing mechanism includes a pressing member (50) for each of the piezoelectric actuators vertically penetrating the ceiling wall (25) of the heating furnace, and each pressing member controls the driving member of each piezoelectric actuator in a predetermined position. 7. The piezoelectric actuator inspection device according to claim 1, wherein the piezoelectric actuator inspection device is configured to press with a load of . The energization measurement unit includes a probe holder (53) with a plurality of energization probes (52) corresponding to the terminals of each piezoelectric actuator, the probes being removably and positionally adjustable;
Any one of claims 1 to 7, wherein the probe holder is configured to move between a use position located at the bottom of the pallet and a preparation position pulled out from below the heating furnace. The piezoelectric actuator inspection device described in . The piezoelectric actuator inspection device according to any one of claims 1 to 8, wherein a soundproofing material (73) is provided so as to cover the periphery of the heating furnace. The inspection device main body is unitized and a plurality of pieces are installed side by side,
The piezoelectric actuator inspection device according to any one of claims 1 to 9, wherein the plurality of inspection device main bodies are integrally covered with a heat-insulating safety cover (74). 11. The piezoelectric actuator inspection device according to claim 10, wherein a chimney-like cover (75) for discharging heat from each of the inspection device main bodies is provided on the ceiling portion of the safety cover.