JPH0431813B2 - - Google Patents

Description

[Detailed description of the invention] Industrial application field This invention is an improved automatic tool changer (hereinafter referred to as ATC) used in machining centers, etc.
Regarding.

Prior Art Conventionally, the tool change speed of ATC was usually set to a slow speed suitable for heavy tools in consideration of safety. In recent years, there has been a strong need for faster ATC operation in order to increase efficiency, and for this reason, the method proposed in JP-A-60-67044 is equipped with a drive member that can obtain two speeds, and uses a weight classification recorded on an NC tape. Accordingly, light tools are replaced at high speed and heavy tools are replaced at low speed. Furthermore, Japanese Patent Application Laid-Open No. 62-102939 states that changing heavy tools at low speed from the beginning is time-consuming and inefficient, especially when the moving distance of the moving parts is long. Some tools attempt to achieve this goal by changing the tool at high speed and changing the deceleration rate in response to the tool weight recorded on the NC tape before the stop position to reduce the impact caused by inertia when stopping.

Problems to be Solved by the Invention The methods of JP-A-60-67044 and JP-A-62-102939 both control the ATC operation based on the tool weight recorded on the NC tape, but most In the bottle grip type gripping method adopted by the tool changing arm of the present invention, control should be performed not only by weight but also by weight moment. Furthermore, the method of controlling operating speed using weight data recorded on NC tape does not have a mechanism to check if, for example, an operator mistakenly uses a large tool that exceeds the weight limit in order to increase efficiency, and this can lead to tool drop accidents. This has the problem of causing

Means for Solving the Problem The pot of the pivot arm is provided so as to be able to pivot in the vertical direction about a horizontal axis, and a piezoelectric element for detecting the weight moment of the pot is provided on the pivot arm so that the pot is supported without any gap. A control device that stores a moment limit value, selects a tool change speed corresponding to the weight moment of the replaced tool based on this limit value and the signal output of the piezoelectric element, and issues an alarm stop when the maximum limit value is exceeded. It is equipped with the following.

Embodiments Hereinafter, embodiments of the present invention will be described based on the drawings. In a well-known horizontal machining center, a saddle 2 is fixed to the front side of the upper surface of a bed 1. A turning table 3 is provided on a sliding guide surface cut in the upper surface of the saddle 2 in the X-axis direction so as to be able to turn and move and position it. Further, a column 4 is mounted on a sliding guide surface in the Z-axis direction cut on the rear side of the upper surface of the bed 1 so as to be movable and positionable.
A spindle head 5 is movably positioned on a sliding guide surface in the Y-axis direction provided at the center of the spindle head 5, and a spindle 6 is rotatably supported on the spindle head 5. Furthermore, a tool magazine device 7 is installed on the left side of the column 4, and a magazine pot 8 for storing a plurality of tools T with the tool axis perpendicular to the main shaft 6 is connected endlessly by a ring-shaped chain to a drive splitter (not shown). It is indexed to index position A by the indexing device. Further, a sub-arm device 9 is attached to the side surface of the column 4 on the tool magazine side. Sub-arm 1 of sub-arm device 9
0 has a gripping claw that grips the tool T, and is movable in the axial direction of the magazine pot and vertically along the guide rail by a drive mechanism (not shown), and is positioned at the index position A of the magazine and on the column 4. Tools are exchanged and conveyed between magazine-side rotational positions B of the installed ready station device 11, which will be described later. Swivel arm 1 of lady station device 11
Reference numeral 2 denotes a spindle 1 that is vertically fitted onto a spindle support 14 fixed on the lady station frame 13.
5 is rotatably supported via a plurality of bearings,
It is rotated by the 90° rotation actuator 16 to the above-mentioned magazine side rotation position B and ATC side rotation position C. Then, a hydraulically driven positioning pin (not shown) provided on the lower surface of the swing arm 12 engages with a positioning block 17 fixed at a corresponding position on the reception station frame 13, thereby moving the swing arm 12 to swing positions B and C.
positioning is performed. Furthermore, a horizontal support pin 2 is attached to the pot holding portion 12a at the tip of the rotating arm 12.
The lady station pot 22, whose tip end is pivotally supported by the arm 1, is pivotable in a vertical plane, and its rear end is held tightly between a lower base 23 and an upper piezoelectric element 24. Then, the piezoelectric element 24 sends a voltage corresponding to the weight moment of the next tool T inserted into the receiving station pot 22 to a control device (not shown), and the control device sends a voltage corresponding to the weight moment of the next tool T inserted into the reception station pot 22 to an ATC 20 (described later) based on a pre-stored limit value of the weight moment. The operating speed of the twin arm 25 is commanded. Provided at the center between the ATC side rotation position C of the ready station and the tool exchange position E of the main spindle 6, and performs tool exchange between the main spindle 6 and the ready station pot 22.
The ATC 20 is provided on the front surface of the column 4 with the pivot axis of the twin arm 25 parallel to the main axis. The twin arm 25 is rotatable between a horizontal standby position and a vertical tool insertion/extraction position, and is movable in the direction of the rotation axis.The twin arm 25 is driven by a variable speed motor provided in a gear box (not shown). For example, a pole number changing motor can be used as the variable speed motor.

Function The magazine pot 8 of the tool magazine device 7 stores a plurality of tools T necessary for machining, and the NC
The next tool T is indexed to index position A by the next tool command of the device. The indexed next tool T is extracted by the sub-arm 10 and rises along the guide rail,
At the rotating position B, it is inserted into the lady station pot 22 at the tip of the rotating arm 12. A piezoelectric element 24 that is in contact with the upper rear end of the reception station pot 22 receives pressure according to the weight moment of the tool T and generates a voltage, which is sent to a control device (not shown). The control device then compares the weight moment with a pre-stored limit value. For example, if the voltage is below the limit value, the weight moment is considered to be within a safe range and high-speed operation is commanded. If so, low speed operation is commanded. In addition, if the voltage exceeds the stored maximum limit value, it will be assumed that the limit value of the weight moment that can be replaced has been exceeded, and the replacement operation will be stopped, and a tool abnormality alarm will be issued to the operator, indicating that the maximum limit value has been exceeded. The exchange arm 12 into which the next tool is inserted will not operate thereafter. Next, the swivel arm 12 into which the next tool T for which high-speed or low-speed operation has been commanded is inserted is rotated by supplying pressure oil to the cylinder rear chamber of the 90° swivel actuator 16, and at the swiveling position C, a tool change command is issued from the NC device. Wait until it comes out. When the cutting process with the tool T attached to the spindle 6 is finished, the spindle head 5 is positioned at the tool change position E, and when a tool change command is issued from the NC device, for example, if the above-mentioned command is for the next tool of low speed operation, the twin arm 25 is rotated by 90 degrees to become vertical by the variable speed drive motor switched to the low speed side, and simultaneously grips the used tool T of the main spindle 6 and the next tool T in standby. Next, the twin arm 25 moves forward in the direction of the rotation axis, extracts both tools at the same time, rotates further 180 degrees, and then retreats in the axial direction to insert the next tool T into the spindle 6 and the used tool T into the ready station pot 22. . Next is Twin Arm 25.
It turns 90 degrees, becomes empty, and waits in a horizontal position.

The tool T inserted into the spindle 6 is clamped by a clamping device (not shown), and the spindle head 4 moves downward in the Y-axis direction, leaves the tool exchange position E, and begins cutting. Further, the used tool inserted into the lady station pot 22 is returned to the magazine pot 8 by the reverse operation described above. During the transportation of the used tool for return, no tool exchange command is issued due to the weight moment. When the used tool is returned to the magazine pot 8, the next tool T is subsequently given a next tool command from the NC device in the above-described manner, and the next tool T is judged based on the weight moment at the turning position b, and high-speed or low-speed operation is commanded. The next tool T is moved to the rotation position C and stands by. Even if the command based on this weight moment is, for example, a high-speed operation, if a tool that is instructed to operate at a low speed is attached to the spindle 6 as described above, the twin arm 25 performs tool exchange at a low speed. Further, when the next tool T exceeds the maximum limit value and a command to stop is issued, a warning is issued to the operator as a tool abnormality alarm, and the next tool T stops at the rotation position B.

Effects As detailed above, the present invention is equipped with a tool weight moment measurement member and a control device that stores limit values in advance to control the ATC speed and stop the alarm. It is possible to perform ATC operation at the optimal speed, making the ATC operation stable, safe and reliable. Furthermore, if a tool exceeding the maximum limit is attempted to be used, the operator is alerted to the danger and manual operation can be performed. This has the effect of making the machine even more safe by changing tools, and also has the effect of improving efficiency by shortening idle time.

[Brief explanation of drawings]

Fig. 1 is a top view of a ready station having a weight moment measurement unit according to the present invention, Fig. 2 is a partially cutaway side view of Fig. 1, and Figs. 3 and 4 are views of a horizontal machining center. It is a diagram. 12...Swivel arm, 20...Automatic tool changer, 21...Support pin, 22...Ready station pot, 24...Piezoelectric element.

Claims (1)

[Claims] 1. In a machine tool with an automatic tool changer, a pot of a swing arm is provided so as to be vertically swingable about a horizontal axis, and a piezoelectric element for detecting the weight moment of the pot is provided on the swing arm so that the pot is supported without a gap; A weight moment limit value is stored in advance, and a tool change speed corresponding to the weight moment of the replacement tool is selected based on this limit value and the signal output of the piezoelectric element, and an alarm is stopped when the maximum limit value is exceeded. An automatic tool changer characterized by comprising a control device.