JP2543225B2 - Non-round display device - Google Patents

Description

The present invention relates to a three-dimensional non-round display device.

(Prior Art) With the work attached to the main shaft of a numerically controlled (hereinafter referred to as NC) lathe, the work rotation axis is the C axis, the work rotation center axis is the Z axis, and the axis orthogonal to this Z axis. With X as the X-axis, an arbitrary position on the Z-axis is fixed, and the shape of the work represented by the rotation angle of the C-axis and the position of the X-axis is called the circumferential cross-sectional shape, and the arbitrary rotation angle of the C-axis is fixed. The shape of the work represented by the Z-axis position and the X-axis position is referred to as a longitudinal cross-sectional shape.

Conventionally, the parallel projection method has been used to display a work shape having a three-dimensional shape. This method has an advantage that a three-dimensional shape can be expressed well even in a projected image on one surface by appropriately setting the projection angle with respect to the projection surface. By performing parallel projection of the target work shape on the three planes, the size and shape can be accurately defined. An apparatus for displaying a projected image using such a parallel projection method on a graphic display means such as a CRT screen will be described as a prior art.

FIG. 13 is a diagram showing a schematic shape of a piston having a three-dimensional non-round shape used for an internal combustion engine. In order to show the appearance of the work after machining and the three-dimensional non-round shape, the non-round amount at the position of the circumferential cross section, ... is emphasized. The appearance of the work after machining is piston ring groove,
Piston pin holes and the like are machined, but the target of shape display here is only the three-dimensional non-round shape.

Here, the reason why the piston shape is processed into a non-round shape will be described.

In recent years, technical problems of internal combustion engines (hereinafter referred to as engines) include high output due to high rotation and low noise due to low vibration, and in order to solve these problems, uniform clearance between the cylinder and piston of the engine is required. I had to keep it. Generally, in a water-cooled engine, the heat management of the cylinder wall is easy, and the thermal displacement can be made uniform. Compared to this, the piston, which is the movable part, has a temperature distribution in the upper part of the piston that contacts the combustion chamber (hereinafter called the top part) and in the lower part of the piston that does not contact the combustion chamber (hereinafter called the skirt part) even when combustion is stable. Is not uniform. Further, aluminum material is used for weight reduction, but this material has a larger coefficient of linear expansion than iron material, and the amount of thermal displacement differs depending on the thickness of the aluminum material of the piston itself. Therefore, if an accurate cylindrical piston is used, the temperature will be higher near the combustion chamber, and the amount of expansion tends to increase from the top to the skirt. The amount of expansion differs depending on the difference in wall thickness.

For the above reasons, the piston is machined in advance into a three-dimensional non-round shape so that it has an accurate cylindrical shape during stable combustion and the gap between the cylinder and the cylinder is uniform.

Conventionally, a piston having a three-dimensional non-round shape has been processed by a copying lathe using a master cam. Product inspection of the piston after processing is performed by measuring the shape of the circumferential cross section at the specified longitudinal position and measuring the shape of the longitudinal cross section at the specified rotation angle. If there was a smooth change, it was accepted. Therefore, when piston machining is performed on an NC lathe, all the shape data specified above is input to determine the three-dimensional non-round shape, but there is no means for confirming the shape of the interpolated portion. Therefore, the actually machined shape is measured, and the data of the portion having a large shape error is additionally input to bring the shape closer to the master cam shape, which requires a lot of man-hours until the shape data is completed. As a concrete example, there is a machine tool for machining a workpiece having a non-circular cross section, which is disclosed in JP-A-1-271102. In this example, smooth shape data is created by interpolation, but no means for indicating the interpolation result is provided. The expression “smooth” is difficult to define, and it is fully conceivable that what is desired in the piston differs from that of the interpolation function. Therefore, in the case of a delicate shape such as a piston having a three-dimensional non-round shape, it is required to correct and add the input data while checking the interpolation result to adjust the smoothness. However, there was no suitable three-dimensional non-round display device.

Next, a conventional technique for displaying a three-dimensional non-round shape will be described. FIG. 14 is a diagram in which the shape described in FIG. 13 is projected onto one plane in parallel, and in this figure, the shape of a piston having a three-dimensional non-round shape with a small non-round amount is displayed. Not suitable. For example, when the piston outer diameter shown in FIG. 13 is about 80 mm and the non-roundness is about 0.1 to 0.2 mm, the non-roundness cannot be shown in the display of FIG.
However, the amount of non-roundness means the difference between the maximum radius and the minimum radius within a certain circumferential cross section. Assuming that the shape of the milk bottle has a large non-roundness, an example of the milk bottle of FIG. 3 is shown, and when this example is projected in parallel on three planes like the triangle method used in drawing, it becomes as shown in FIG. However, it is found that this triangular display method is not suitable for displaying a non-round shape. In order to accurately define the shape, an auxiliary cross section had to be added separately.

(Problems to be Solved by the Invention) Shape data of a cross section in the circumferential direction or shape data of a cross section in the longitudinal direction are input, and the shape data of a portion that has not been input uses a known interpolation function to interpolate three-dimensional When creating the shape data of a perfect circle, there is no means for simply indicating whether the created shape data is a desired shape. Therefore, it is not possible to know whether the shape of the interpolated part is acceptable without actually performing machining, so it is necessary to repeat the processing, measurement, and addition / correction of shape data, which consumes a lot of man-hours. It was

That is, when an NC lathe is used for machining a piston having a three-dimensional non-round shape of a conventional internal combustion engine, simple input, that is, data of a portion which is not input is created by interpolating using a known interpolation function. , There was no way to check at the data level whether a subtle shape was formed by interpolation. Therefore, the machining efficiency is low because the machined workpiece is measured and the input data is added or corrected.

The present invention has been made under the circumstances as described above,
It is an object of the present invention to clearly display a three-dimensional non-round shape by the data of the interpolated portion so that the data can be added or modified before the machining, thereby improving the machining efficiency. It is to provide a shape display device.

(Means for Solving the Problem) The present invention provides the above-mentioned problem by providing a means for accurately displaying the shape of the result interpolated by a known interpolation function as a graph and a data value on a graphic display means such as a CRT screen. Has been resolved. That is, according to the present invention, the workpiece rotation axis is the C axis, the workpiece rotation center axis is the Z axis, and the axis orthogonal to the Z axis is the X axis while the workpiece is attached to the spindle of the numerically controlled machine tool. The present invention relates to a non-round shape display device that displays a three-dimensional non-round shape using these coordinate values, and the above object of the present invention is to replace the X-axis coordinate value with a distance from a reference point that can be arbitrarily set. Replacement means, Z
Input means for inputting axial coordinates and C-axis coordinates, and displaying the non-round cross-sectional shape at the input Z-axis coordinate position in an orthogonal coordinate system using the values of the C-axis and the substituted X-axis. And a second display for displaying the non-round shape cross-sectional shape at the input C-axis coordinate position in an orthogonal coordinate system using the values of the Z-axis and the replaced X-axis. And means.

(Operation) In the present invention, a three-dimensional non-round work generally has a workpiece rotation axis of C axis and a workpiece rotation center axis of Z axis, where Z is the position Z and C is the rotation angle C. And the distance R from the position Z of the Z axis. Thus, the work shape is represented by P (Z _P , C _P , R _P ). Here, a reference point R that can be set arbitrarily to represent only the non-roundness
Set _BASE and set _{P P} = R _P −R _BASE to P ′ (Z _P , C _P , X
_P ) and put each component in the Cartesian coordinate system. In this orthogonal coordinate system, the vertical axis is the X axis, the first axis of the horizontal plane is the Z axis, and the second axis is the C axis. Images projected in parallel on the CX plane and the ZX plane are displayed on a CRT screen or the like. Display on the graphic display means. As a result, the interpolation shape can be easily confirmed even with a piston having a particularly small non-roundness, and the machining efficiency is improved.

(Embodiment) This embodiment is a case where it is applied to an automatic programming device for an NC lathe, and FIG. 1 is an external view thereof, a power switch 10 and a main body 20 having two floppy disk drives 11, and a collar. It is composed of a CRT 12 and a keyboard 13 including various command keys, numerical data keys and character keys.

FIG. 2 is a system configuration diagram. The main body 20 has a main processor 21, ROM22, RAM23, and various interfaces.
Has 30-35. The above-mentioned colors for peripherals
CRT12, keyboard 13, floppy disk drive 1
1 available, monochrome / color hardcopy 1 as needed
4, The tape reader / puncher 15 and the printer 16 can be additionally connected.

FIG. 3 is an example of a three-dimensional non-round shape created by inputting shape data of circumferential cross sections A to C, and the shape model is a milk bottle. Since the shaded area is not interpolated by a known interpolation function, it does not relate to the following description. The shape after interpolation is defined by the Z-axis position Z, the C-axis rotation angle C, and the distance R from the Z point. Therefore, an arbitrary point P that makes up the shape is represented by three coordinate components (Z _P , C _P , R _P ), and the value is
R _P represents the radius of the work shape and is equal to the X axis position of the NC lathe. However, the shape error due to the nose R of the cutting tool is not considered. A model of the shape shown in FIG. 3 is represented as shown in FIG. 4 with the above three components as an orthogonal coordinate system. In this Cartesian coordinate system, the radius R _{P of the} work shape is taken as the vertical axis to be the X axis, and the Z axis and the C axis rotation angle are taken as the linear axes in the horizontal plane to be the C axis. However, the rotation angle is a value within one rotation.
When the shape of FIG. 3 is transferred, it becomes like FIG. However, since it is not possible to display a minute non-round shape as it is, a reference radius that can be set arbitrarily, that is, the reference position R _BASE of the X axis is input, and the relative position from this reference position R _{BASE is} shown in FIG. To display. This figure is a diagram in which the work shape radius in the circumferential cross section C is R _O , R _BASE = R _O , and the X-axis component at point P is (R _P −R _BASE ). As a result, even if the amount of non-roundness is extremely smaller than the work shape radius, it is possible to accurately display the non-roundness. P in Fig. 3
(Z _P , C _P , R _P ) moves to P '(Z _P , C _P , X _P ) in FIG. However, _XP = R _P -R _BASE .

In this embodiment, using the above conversion, the following 3
Display dimensional non-round shape. To confirm the shape interpolated by the known interpolation function, the position of the Z axis and the rotation angle of the C axis are input and parallel projection views of the circumferential section and the longitudinal section are displayed. Let Z _{P be} the input Z-axis position and C _{P be} the rotation angle of the C-axis.
The rotation angle of the Z _A and C axes is set to 0 °, the time during which the key on the keyboard 13 is pressed is measured, and the above values Z _P and C _P are updated. The basic unit time is t ₀ and the key pressing time is t
Further, assuming that each update amount updated per basic unit time t ₀ is ΔZ, ΔC, Z _P , C _P is Z _P = Z _A + ΔZ × INT (t / t ₀ ) C _P = ΔC × INT (t / t ₀ ) (1) However, INT (t / t ₀ ) means only the integer value of the quotient of t / t ₀ .

Is represented by In this embodiment, ΔZ has two steps in two directions of increasing and decreasing, and is changed using four keys 41 and 44 as shown in FIG. The keys 41 to 44 can be moved by 0.001 mm in the arrow direction, and the keys 42 and 43 can be moved by 0.1 mm in the arrow direction.

Regarding ΔC, the angle is expressed in degrees, and a key having a guide map corresponding to the above keys 41 and 44 is adopted as a range from 0 to 360 degrees, and the keys can be moved in units of 1 degree. The input means, automatically the value Z _P by pressing the key in accordance with the guidance diagram as in FIG. 7, can change the C _P, no problem at all in practice be directly input Z _P, the C _P. By the values Z _P and C _P input in this way, Z- in FIG.
Since the position in the C plane is determined, the circumferential cross section is shown in FIG. 8 and the longitudinal cross section is shown in FIG. X _P at this time
The value of is obtained from Z _P and C _P input by a known interpolation function, and this cross section is displayed as shown in FIG. In FIG. 7, the set values Z _P and C _P are displayed numerically at the same time, and the value of X _P of the point P ′ on the shape is also displayed. When the key is pressed, the values Z _P and C _P are updated. Check the displayed numerical data and release the key to display the shape. This is because it takes a long time to process the display, and if the display can be performed at high speed, there is no problem even if the shape is displayed in real time every time a key is pressed. The displayed rotation angle range is 0 to 360
Although the degree is fixed, the length in the Z-axis direction is (Z _C -Z _A ), and the Z-axis scale is automatically determined, although it varies depending on the work shape, and the display length is almost constant for long and short work. Become.

Also in the X-axis direction, the maximum and minimum values after interpolation are checked before display, and the X-axis scale is also automatically determined. With this display method, only one cross section can be displayed in the circumferential direction and the longitudinal direction at the same time. Therefore, the screen memory (RAM 23) has a function of storing a set of the circumferential cross section and the longitudinal cross section as one set. There are two screen memories. The memory operation is performed by pressing the specific key displayed as "Hold", and the data in the screen memory is cleared by pressing the specific key displayed as "Clear". To be done. The stored data in the screen memory is displayed as a broken line in FIG. In this case, the line color may be changed and displayed.
In this embodiment, up to two screens can be stored in the screen memory. By using this function, it is possible to determine on the graphic screen what the respective cross-sectional shapes at the currently displayed position are with respect to the shapes of the circumferential cross section and the longitudinal cross section that are defined in advance. In other words, it is possible to easily confirm the undulation state of the longitudinal cross section and the changing state of the unspecified circumferential cross section by superimposing display.

Figure 10 shows two points P ₀ (Z ₀ , C ₀ , X ₀ ), P ₁ (Z ₁ , C ₁ , X ₁ ).
Shows a display example when the screen memory function is used. The shape stored in the screen memory is represented by a broken line and the coordinate values are represented by a dotted line. The point P ₀ is determined so as to have the maximum radius at the Z-axis position Z ₀ and the C-axis rotation angle C ₀ , and the point P ₁ is the Z-axis position Z ₁ and the C-axis rotation angle C. _It was decided so that it would be the minimum radius in ₁ . As a result, the smoothness as a whole can be evaluated depending on the relationship between the solid line of the point P'currently displayed in the display of the longitudinal section and the broken line. Similarly, in displaying the cross section in the circumferential direction, the non-round shape can be easily understood by looking at the relationship between the solid line and the broken line. For example, paying attention to the cross section in the circumferential direction, since there are four cycles of peaks per rotation and the phases are the same, it is confirmed that the cross section in the circumferential direction has no quadrilateral twist. Similarly, focusing on the longitudinal cross section, the straight non-circular amount of a square is constant between the positions Z _A and Z _B , and the non-round amount of a square is a curve between the positions Z _B and Z _C. And the line segment shown by the solid line must be between the broken line showing the maximum outer diameter passing through the point P ₀ and the broken line showing the minimum outer diameter passing through the point P _1. I also understand. This agrees with the model of the milk bottle shown in FIG. 3, and indicates that the interpolation is good by inputting the three cross-sections A to C in the circumferential direction. A block diagram of the present invention is shown in FIG. 11, and here the shape of FIG. 3 is considered as an example.

There is a shape data input means 1 for inputting shape data of the circumferential direction cross sections A to C, and a shape for determining a three-dimensional non-round shape by using a known interpolation function based on the input shape. It has defining means 2 and Z / C coordinate input means 3 for designating the determined display position of the three-dimensional non-round shape. Further, the shape at the position to be displayed based on the outputs of the shape data inputting means 1, the shape defining means 2 and the Z / C coordinate inputting means 3 is interpolated from the already determined three-dimensional non-round shape to display data. Interpolation calculation means 4 for obtaining
A storage means 5 for storing the obtained display data, a storage start means 6 for instructing the storage means 5 to start fetching the display data, and a memory erasing means for instructing to erase the display data. 7 is provided, and display means 8 for receiving the display data and displaying the data as shown in FIG. 10 is provided.

The present invention will be described with reference to the flowchart of FIG. Similar to the above, consider the shape of FIG. 3 as an example.

First, the shape data from the circumferential section A to C is input (step S1), but what is actually input is the point group represented by the Z, C, and X axis coordinate values. Then, based on the input shape data, the shape of the non-input portion is determined by using a known interpolation function for the three-dimensional shape (step S
2). That is, the function formula of how to define the points between the input shape data is determined. Next, the Z and C axis coordinate values for determining at which position the determined three-dimensional non-circular circumferential cross section and longitudinal cross section are to be displayed are input (steps S3 and S7). Display data is created based on the Z and C axis coordinates input in steps S3 and S7 (step S4), and the display data is displayed on the display means 8 such as a CRT (step S5). Here, the display data can be stored using the storage means 5 and can be kept displayed on the display means such as a CRT screen. Then, it is selected whether or not to end the display of the shape (step S6).

(Effects of the Invention) As described above, according to the non-round display device of the present invention,
Whether or not the three-dimensional non-round shape determined by interpolation is the desired shape is known at the time of creating the interpolation data. Therefore, the man-hours that have been conventionally consumed, such as machining, actual measurement, addition of shape data, and correction, can be repeated. It can be reduced significantly.

[Brief description of drawings]

FIG. 1 is an external view of an automatic programming device embodying the present invention, FIG. 2 is a system configuration diagram of the automatic programming device, and FIG. 3 is a diagram showing the external appearance of the shape of a milk bottle as an example of non-roundness. Fig. 4 is a diagram showing the shape of a milk bottle transferred to a Cartesian coordinate system, Fig. 5 is a diagram in which the X coordinate unrelated to the non-round shape is taken as a reference point, and Fig. 6 is the Z axis using the keyboard keys. A guide map for inputting coordinates, FIG. 7 is a diagram in which an image obtained by parallel projection is displayed on a graphic display means such as a CRT screen, and FIG. 8 is an input Z-axis coordinate Z _P.
Fig. 9 is a diagram showing a cross section in the circumferential direction obtained by Fig. 9, Fig. 9 is a diagram showing a cross section in the longitudinal direction obtained by the input C-axis coordinate C _P , and Fig. 10 shows the screen memory function at points P ₀ and P ₁ . FIG. 11 is a block diagram showing an embodiment of the present invention, FIG.
Fig. 13 is a flowchart showing an example of its operation, Fig. 13 is a diagram showing the external appearance of a piston for an internal combustion engine and a three-dimensional non-perfect circular shape in a circumferential sectional shape ~, and Fig. 14 is a parallel projection on one plane. FIG. 15 is a diagram showing a projected image in the case of performing the above, and FIG. 15 is a diagram when the shape of the milk bottle in FIG. 3 is projected in parallel onto three planes orthogonal to each other. 1 ... shape data input means, 2 ... shape defining means, 3 ... Z / C
Coordinate input means, 4 ... Interpolation calculation means, 5 ... Storage means, 6 ...
Memory starting means, 7 ... memory erasing means, 8 ... display means.

Claims (3)

(57) [Claims] 1. A numerically controlled machine tool in which a workpiece is attached to a spindle, a workpiece rotation axis is a C axis, a workpiece rotation center axis is a Z axis, and an axis orthogonal to the Z axis is an X axis.
In a non-round shape display device that displays a three-dimensional non-round shape using these coordinate values, a replacement unit that replaces the X-axis coordinate value with a distance from a reference point that can be arbitrarily set, Z-axis coordinates, and C. Input means for inputting axis coordinates, and a first for displaying the non-round cross-sectional shape at the input Z-axis coordinate position in an orthogonal coordinate system using the values of the C-axis and the replaced X-axis. Display means and second display means for displaying the non-round shape cross-sectional shape at the input C-axis coordinate position in an orthogonal coordinate system using the values of the Z-axis and the replaced X-axis. A non-round display device characterized by the above. 2. The first display means compares a time during which a key in a predetermined keyboard is pressed with a preset unit time, and the Z-axis coordinate or The non-round display device according to claim 1, further comprising means for adding a predetermined update amount to the value of the C-axis coordinate. 3. A display shape for memorizing a shape currently being displayed by pressing a key in a predetermined keyboard and erasing the memorized shape by pressing another key in a predetermined keyboard. 2. The non-round display device according to claim 1, further comprising one or more storage means, wherein the stored shape is retained in the second display means until it is erased.