JP5274313B2 - Pallet changer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To normally perform a pallet changing operation, regardless of magnitude of the weight of a workpiece placed on a pallet and without hindering deposit of cut chip, etc. <P>SOLUTION: This pallet changer includes a plurality of fluid pressure cylinders 44 for elevating/lowering an elevating/lowering frame 24 mounted with the pallet P placed with the workpiece when carrying the workpiece in/out of a machine tool 11. Each of the fluid pressure cylinders 44 includes a piston rod 45 having a connected upper end so that fluid pressure may be applied to a bottom surface of the elevating/lowering frame 24. The piston rod 45 has a spherical upper end face 71 having a center on an axis of the piston rod 45. In the bottom surface of the elevating/lowering frame 24, a downward tapered positioning surface 92 is formed to be brought into line-contact with the upper end face 71 of the piston rod 45 in an annular line part. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a pallet exchanging apparatus for automatically exchanging a pallet on which a workpiece to be machined by a machine tool is placed.

  This type of pallet exchanging device includes a lifting frame on which a pallet on which a workpiece is placed is placed and a lifting means for raising and lowering the lifting frame when loading and unloading the workpiece with respect to the machine tool. There is known a means comprising a toggle link mechanism (for example, see Patent Document 1).

  In this pallet changer, the driving force for raising and lowering the pallet on which the workpiece is placed is generated by the toggle link mechanism. However, the toggle link mechanism can be generated for a relatively heavy workpiece. There was a limit in the magnitude of the driving force, and it was impossible in strength. In addition, chips and the like are likely to accumulate on the toggle / link mechanism, which may hinder normal operation of pallet replacement.

JP 2004-291181 A

  An object of the present invention is to provide a pallet exchanging apparatus that can normally perform a pallet exchanging operation regardless of the weight of the work on which the pallet is placed, and without causing any trouble in the accumulation of chips and the like. is there.

  The pallet exchanging apparatus according to the present invention comprises a lifting frame on which a pallet on which a workpiece is placed is placed and a lifting means for raising and lowering the lifting frame when the workpiece is carried in and out of the machine tool. However, each fluid pressure cylinder has a piston rod having an upper end connected so that fluid pressure can be applied to the bottom surface of the lifting frame.

  In the pallet exchanging device according to the present invention, the advancing / retreating operation of the piston rod of the fluid pressure cylinder is directly transmitted to the elevating frame, thereby elevating the elevating frame. It is possible to freely set the size and / or number of fluid pressure cylinders corresponding to the weight of the work to be placed on the pallet, which is related to the weight of the work to be placed on the pallet. In addition, the pallet replacement operation can be performed normally without any trouble in the accumulation of chips and the like.

  Further, the piston rod has a spherical upper end surface centered on the axis of the piston rod, and a downward tapered positioning surface that can be in line contact with the upper end surface of the piston rod at the annular line portion on the bottom surface of the lifting frame. If formed, the spherical upper end surface and the tapered positioning surface of the piston rod form a so-called floating mechanism, and the amount of advancement and retraction of the piston rods of the plurality of hydraulic cylinders varies, and the lifting frame is inclined. Even if there is, the floating mechanism absorbs the inclination. Thereby, an excessive force is not applied to the piston rod.

  In addition, a connecting member that is attached to the bottom surface of the lifting frame and has a positioning surface and that has the positioning surface, and an assembly jig are provided. A pin hole is formed, and a vertical upper pin hole that is coaxial with a taper axis formed by the positioning surface is formed on the top wall of the positioning surface in a vertically penetrating manner. If it has a positioning pin that can be removably inserted through the upper pin hole, and if the positioning pin is inserted through the lower pin hole and the upper pin hole, the assembly jig causes the horizontal position of the lifting frame relative to the hydraulic cylinder Misalignment can be corrected.

  By preventing this misalignment, the contact between the spherical surface of the upper part of the piston rod of each cylinder and the downward taper surface of the elevating frame is suppressed, resulting in a circular line contact. In the case of a smooth contact, generation of force in the horizontal direction of the piston rod caused by the contact position of the taper and the sphere can be suppressed. If this horizontal force is generated, a resistance force is generated between the piston rod and the cylinder, which hinders the uniform operation of each cylinder. Occurrence can be avoided in advance.

  Further, when the hydraulic oil from the hydraulic unit is supplied to each fluid pressure cylinder via the flow dividing valve, the hydraulic oil with a uniform flow rate can be supplied to each cylinder.

  According to the present invention, there is provided a pallet exchanging apparatus capable of normally performing a pallet exchanging operation regardless of the weight of the work on which the pallet is placed and without causing any trouble in the accumulation of chips and the like.

It is a perspective view of the machine tool provided with the pallet exchanging device by this invention. It is a front view of the pallet exchanging device. It is the same top view. It is a hydraulic circuit diagram of the fluid pressure cylinder of the pallet exchanging device. It is sectional drawing which shows the connection structure of a fluid pressure cylinder and a raising / lowering frame in detail.

  In the following description, referring to FIG. 1 as a reference, the front and rear refer to the side indicated by the arrow A in FIG. 1 as the front and the opposite side as the rear, and the left and right refer to the left and right sides as viewed from the front. It shall be left and right.

  Referring to FIG. 1, a machine tool 11 and a pallet exchanging device 12 provided on the right side of the machine tool 11 are shown.

  The machine tool 11 is provided with a first station S1 and a second station S2 at the front and rear. The pallet P on which a work (not shown) is placed is moved from the first station S1 to the second station S2, and during this time, the work is processed. The movement of the pallet P is performed by a table (not shown) of the machine tool 11.

  The pallet changer 12 is provided with a third station S3 and a fourth station S4 at the front and rear. From the third station S3, the pallet P on which the workpiece before processing is placed is carried into the first station S1. From the second station S2 to the fourth station S4, the pallet P carrying the processed workpiece is carried out.

  As shown in FIGS. 2 and 3, the pallet changer 12 includes a base frame 21 having a third station S3 and a fourth station S4 provided on the top surface, and a pallet P from the fourth station S4 to the third station S3. A transport table 22 for transporting the pallet, a moving means 23 for moving the transport table 22 in the front-rear direction, and a lifting frame for delivering the pallet P to the transport table 22 and carrying the pallet P to and from the machine tool 11 24 and lifting means 25 for moving the lifting frame 24 up and down.

  The transport table 22 is supported by guide means (not shown) so as to be movable back and forth, and supports the left and right edges of one pallet P, respectively, and a pair of left and right base bodies 31 forming a single surface mounting portion; It consists of a horizontal connecting bar 32 that is secured between the two main bodies 31.

  The moving means 23 is composed of a forward / backward moving fluid pressure cylinder 33 mounted on the base frame 21 forward. The piston 34 of the fluid pressure cylinder 33 is connected to the right base body 31.

  The elevating frame 24 includes a pair of left and right horizontal vertical members 41 extending in the front-rear direction disposed at a level higher than the connecting bar 32 inside the moving path of the two main bodies 31 and a front end of the two vertical members 41. And a pair of front and rear horizontal front members 42 extending in the left-right direction and supporting the front and rear edges of one pallet P to form the front one surface mounting portion, and the rear portions of both vertical members 41 The front and rear edges of one pallet P are supported and supported by a pair of front and rear horizontal horizontal members 43 that extend in the left-right direction and form a rear surface mounting portion.

  The front 1 surface placing portion and the rear 1 surface placing portion are combined to form a two surface placing portion as a whole.

  The elevating means 25 is composed of four elevating fluid pressure cylinders 44 that are respectively arranged below the front and rear end portions of the vertical members 41 and are mounted upward on the top surface of the base frame 21. The piston rod 45 of each fluid pressure cylinder 44 is connected so that fluid pressure can act on the corresponding end bottom surface of the corresponding vertical member 41.

  A pair of front and rear horizontal screw rods 51 extending in the left-right direction are disposed on both front and rear edges of the base frame 21. A rotating shaft of a motor 52 is connected to the right end portion of each screw rod 51. A carrying-in pallet engaging member 53 is screwed onto the front screw rod 51, and a carrying-out pallet engaging member 53 is screwed onto the rear screw rod 51.

  FIG. 4 shows a hydraulic circuit of the lifting fluid pressure cylinder 44. The feed port of the hydraulic unit 61 and the inlet port of the diversion valve 62 are connected by a feed pipe 63. The four outlet ports of the diversion valve 62 are connected to the rod advance side of each fluid pressure cylinder 44 by a branch pipe 64. The rod retracting side of each fluid pressure cylinder 44 is connected to the return port of the hydraulic unit 61 by a return pipe 65.

  FIG. 5 shows the connection structure of the lifting frame 24 to the piston rod 45 of the fluid pressure cylinder 44 in detail.

  The upper end surface 71 of the piston rod 45 is formed into a spherical surface. The center of the sphere formed by the upper end surface 71 of the piston rod 45 is on the axis of the piston rod 45. A vertical lower pin hole 72 that is coaxial with the axis of the piston rod 45 is formed in the upper end surface 71 of the piston rod 45. An annular engagement groove 73 is formed on the outer surface of the piston rod 45 at a distance from the upper end surface 71 thereof.

  A connecting member 81 is provided at the piston rod connecting place on the bottom surface of each vertical member 41. The connecting member 81 includes a fixed piece 82 fixed to the same end, and a movable piece 84 that is fastened to the bottom surface of the fixed piece 82 by a bolt 83 so that its position can be changed.

  On the bottom surface of the movable piece 84, a downward rod hole 91 into which the upper end portion of the piston rod 45 is inserted is formed. On the top surface of the rod hole 91, a downward tapered positioning surface 92 that can be in line contact with the upper end surface 71 of the piston rod 45 at an annular line portion is formed. On the top wall of the positioning surface 92, a vertical upper pin hole 93 that is coaxial with the taper axis formed by the positioning surface 92 is formed in a vertically penetrating manner. The fixed piece 82 is formed with an upper and lower penetrating communication hole 94 concentrically with the upper pin hole 93. Furthermore, a work hole 95 is formed in the end of the vertical member 41 in a vertically penetrating manner so as to face the communication hole 94.

  A retaining plate 101 is fastened to the bottom surface of the movable piece 84 by a bolt 83 together with the movable piece 84. The retaining plate 101 is formed with an engagement hole 102 through which the piston rod 45 passes. An inner edge portion of the engagement hole 102 is fitted in the engagement groove 73.

  By the operation of the fluid pressure cylinder 33 for back and forth movement, the transport table 22 is moved in the front and back direction over the third station S3 and the fourth station S4.

  When the pressure oil from the hydraulic unit 61 is distributed by the diverter valve 62 so that the flow rate is uniform, and supplied to each of the lifting hydraulic cylinders 44, the piston rods 45 of all the lifting hydraulic cylinders 44 are all at once. When the advancing and lowering frame 24 is raised and the supply is stopped, the raising and lowering frame 24 is lowered. At this time, the two-surface placement portion of the lifting frame 24 is moved up and down across the placement level of the one-surface placement portion of the transport table 22.

  As the elevating frame 24 is raised, the pallet P placed on the conveying table 22 is transferred from the conveying table 22 to the elevating frame 24 in the third station S3. Thereafter, the pallet P on the lift frame 24 is carried into the first station S1 from the third station S3 by the carrying-in pallet engaging member 53.

  The pallet P on the second station S2 is unloaded from the second station S2 to the fourth station S4 by the unloading pallet engaging member 53, where it is placed on the lift frame 24 that is kept waiting. In the fourth station S4, the pallet P placed on the lifting frame 24 is transferred from the lifting frame 24 to the transport table 22 by the lowering of the lifting frame 24.

  The connection of the elevating frame 24 to the piston rod 45 of the fluid pressure cylinder 44 is accomplished by an assembly operation in which the fixed piece 82 and the movable piece 84 are tightened with the bolt 83. In this case, if the relative positions of the piston rod 45 and the lifting frame 24 of the fluid pressure cylinder 44 are not appropriate, the piston rod 45 is not vertical and may be inclined. If it does so, the sliding resistance at the time of advance / retreat of the piston rod 45 will increase. If this sliding resistance is different for each piston rod 45, it causes malfunction of the flow dividing valve 62.

  It is preferable to use an assembly jig 111 described below for the assembly operation. As shown in FIG. 5, the assembly jig 111 has a round bar-shaped positioning pin 112. On the lower end surface of the positioning pin 112, a small-diameter round bar-shaped positional deviation correction unit 113 is provided.

  The bolt 83 is loosened to such an extent that the relative movement of the fixed piece 82 and the movable piece 84 is free, and in this state, the position deviation correcting portion 113 is moved through the work hole 95 and the communication hole 94 to the lower pin hole 72. And inserted into the upper pin hole 93. Thereby, the lower pin hole 72 and the upper pin hole 93 are aligned on a straight line. At this time, if the upper end surface 71 and the positioning surface 92 of the piston rod 45 are misaligned, both surfaces may not be in line contact at the annular line portion. Can be corrected. After the correction, the fixed piece 82 and the movable piece 84 may be fixed so as not to allow relative movement by tightening the bolt 83.

  In the above, the sequence of the pallet replacement operation is shown as an example, but various variations of the sequence can be considered.

  In the carry-in and fourth stations S3 and S4, the carry-out and carry-in operations may be performed in the opposite manner to the carry-in and carry-out operations described above. Further, the carry-in and carry-out operations may be performed alternately in the carry-in and fourth stations S3 and S4. In that case, the loading and fourth stations S3, S4 are read as loading / unloading stations.

Instead of the movable conveyance table 22, a fixed type cradle may be adopted, and the pallet P may be transferred between the cradle and the lifting frame 24. Furthermore, the above-described one lifting frame 24 may be divided into two divided lifting frames, which are lifted and lowered individually.

  The pallet exchanging device according to the present invention is suitable for achieving automatic exchanging of a pallet on which a workpiece to be processed by a machine tool is placed.

11 Machine tools
12 Pallet changer
24 Lift frame
44 Fluid pressure cylinder
45 Piston rod
71 Piston rod upper end surface
92 Positioning surface
P palette

Claims (2)

When loading / unloading a workpiece into / from a machine tool, the apparatus includes a lifting frame on which a pallet on which the workpiece is placed is placed, and lifting means for lifting the lifting frame. The lifting means includes a plurality of fluid pressure cylinders. Each fluid pressure cylinder has a piston rod whose upper end is connected so that fluid pressure can act on the bottom surface of the lifting frame;
The piston rod has a spherical upper end surface centered on the axis of the piston rod, and a downward tapered positioning surface that can be in line contact with the upper end surface of the piston rod at the annular line portion is formed on the bottom surface of the lifting frame. Pallet changer.   A vertical lower pin hole is provided at the upper end surface of the piston rod that is coaxial with the axis of the piston rod. A vertical upper pin hole is formed on the top wall of the positioning surface so as to be coaxial with the taper axis of the positioning surface. The assembly jig includes a lower pin hole and an upper pin. The pallet exchanging apparatus according to claim 1, further comprising a positioning pin that allows insertion through the hole.

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