DE3405585A1 - Grinding machine - Google Patents

Abstract

Grinding machine for profile grinding, comprising a tool carriage (10) which is displaceable within a plane defined as the primary or main axis (Z), which tool carriage is fitted with a grinding wheel (12) which can be adjusted in a plane located at right angles to the Z-axis and defined as the secondary or regulatory axis (X). A monitoring and control system (20-47) provides the tool carriage (10) and the grinding wheel (12), by way of the drive motors (11, 13), with the required feed movement within the movement planes defined by the abovementioned axes. The monitoring and control system (20-47) comprises a memory unit (43) in which the nominal values of ordinates or ordinate increments of a curve (DE) are stored. This curve (DE) corresponds, without taking standardising factors into consideration, to the profile which is to be given to the workpiece. These values are taken from the memory unit (43), in each case according to the position of the tool carriage (10) and thus of the grinding wheel (12) with respect to the main axis, and are converted into a control signal for the feed of the grinding wheel (12) along the regulatory axis. <IMAGE>

Description

Grinding machine

The invention relates to a grinding machine according to the preamble of claim 1.

The present invention relates in particular to those grinding machines which are used for grinding cylinder jackets, for example of roller bodies are used for rolling mills, around the roller body either a hollow-round, inwardly curved one Profile or a raised, outwardly curved profile corresponding to a predetermined, so-called bombage curve give.

Often the Bombage curve, i.e. that of a roller body conferring profile, the bending line represents the elastic deformation of the cylindrical body.

The camber curve to be executed and thus the path to be described by the machining tool (grinding wheel) depends on the Dimensions of the roller body to be machined (in particular depending on its length) different and is also through the Determines loads to which the roller body is exposed when used in the rolling mill.

More conventional for a numerically controlled grinding machine The machine design would therefore have to be readjusted on a case-by-case basis for the execution of the required camber curve, for example by a long punched tape over which, depending on the length of the roller body, the desired deflection and the Grinding wheel feed the profile information must be entered into the machine. This represents one that should not be neglected Disadvantage.

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They also have other important functions such as balancing the grinding wheel wear, the incrementing of the infeed values in the area of the workpiece ends and the short-stroke honing ("short-stroking" method) must be taken into account in advance when punching the perforated strip, which already means flexible use of the machine excludes.

The most frequent bombing curves, especially those of the elastic deformation bending line The crown curves corresponding to the roller bodies to be machined usually show a course that is limited by a Number of parameters is defined.

In particular, the bending line of a roller body is known from the specified value of the deflection in the plane of symmetry perpendicular to the axis of rotation and from the Length value (chord) derived. In other words: the crowning curves to be executed are independent of the dimensions of the The roller body to be processed is always the same; i.e. they can be derived from a single, standardized reference curve, such as will emerge from the following description.

In the context of the above statements, the main object of the invention is are based on the disadvantages occurring in the prior art in numerical control systems of grinding machines to avoid.

This object is achieved by the features specified in the patent claim.

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Further features and associated advantages emerge from the following description of an exemplary embodiment of a grinding machine device according to the invention, which is shown in the drawings.
Show it:

Fig. 1 is a perspective view of an inventive Grinding machine,

2 shows a roller body with an outwardly curved profile,

3 shows the course of the elastic deformation of a roller body under load when used in the rolling mill;

4 shows the approximate determination of the desired curvature profile by the grinding machine according to the invention,

5 shows a block diagram of a grinding machine according to the invention and 6 shows a roller body with an inwardly curved profile.

In Fig. 1, a grinding machine is shown, which consists of a base 1, on which a bed 2 is mounted, on which horizontal guides 3 and 6 are arranged parallel to each other. 7 and 8 are used to load a clamping head and a counter-clamping head

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draws, which rest on the bed 2 and between the to be processed Workpiece is clamped; for example a roller body 9, which is shown in the drawing with dash-dotted lines is.

The roller body 9 can be clamped rotatably about its longitudinal axis and by drive elements (not shown) of the clamping head 7 be set in a rotating motion.

With a movable tool slide is referred to, which is driven by a motor 11 and within the designated with Z. Direction parallel to the longitudinal axis of the roller body 9 is moved. The direction of movement Z represents the primary or. Main axis (master axis) of the grinding machine.

The tool slide 10 has an acting perpendicular to the main axis Z. Grinding wheel 12 equipped, which, driven by the Motor 13 accommodated in the tool slide 10, perpendicular to the main axis in the direction of movement X of the tool slide 10 can be proceeded. The direction of movement represents the secondary or The standard axis of the grinding machine.

2 shows a roller body 9 ¹ with an outwardly curved profile, that is to say with a profile line which tapers continuously from the center of the roller body to its ends and which is produced by machining with the grinding machine from FIG. In Figure 2, the dash-dotted line 9 indicates the original profile of the roller body before the crown grinding, while with L the machined length of the roller body in the axial direction and with F the circumference of the roller body in the perpendicular to

Rotation axis lying symmetry plane called. For clarification this time frame appears proportionally much larger in the drawing than the value achieved under real conditions.

The profile of the roller body 9 ¹ from FIG. 2 corresponds to the course of the elastic deformation of the roller body under load when used in the rolling mill.

As a rule, the elastic deformation line arises from a cylindrical one Body is known to be an arc of a fourth degree of curvature (described by a biquadratic equation) as in Fig. 3, or by a curve that can be readily derived from this curvature. In Fig. 3, the curved arc denotes DE the course line of the elastic deformation of a roller body with length L. In the case of a roller body, the dimensions of which are given, the course line of the elastic deformation can accordingly can be determined using two parameters, namely using the.

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maximum central deflection under load and based on the length L.

With a change in the dimensions and the applied load, although the line of elastic deformation of the roller body changes, however, while their course always corresponds qualitatively to the curve denoted by DE in FIG. 3. For a quantitative Determining the geometric features of the line of elastic deformation of a roller body is therefore sufficient to specify the maximum Deflection F and the length L of the roller body.

To a roller body a corresponding to the course line of the elastic To be able to give deformation of a curved profile, the grinding machine from FIG. 1 is according to the invention with a monitoring and control system equipped, which is shown in FIG. In the drawing, 20 is an electronic control unit for storage and processing of data with the help of which the machine functions are controlled. This unit is an input unit 21 upstream; For example, a keyboard that the machine operator uses to enter the required control data and machining parameters can enter into the control unit 20.

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The control unit 20 is connected to a positioning device 22 for the Tool slide 10 and thus for the tool 12 in the main axis Z connected. The output of the positioning device 22 is with

23

connected to a comparison device, the output of which is sent to a further comparison device 24 is connected, via a converter 25, which converts the signal output by the positioning device 22 into converts a speed signal. This speed signal is passed on to the drive motor 11 via the comparison device 24. A tachymetric generator 26 or an analog speed sensor is with the output side of the drive motor 11 and with the comparison device 24 in connection, whereby a control loop is formed. The block 2 7 represents the integration of the rotational speed of

Drive motor 11, the given working position of the tool slide 10 and thus of the tool to the main axis Z. A veraleichseinrichtung working between the integrator 27 and the summator Switched position transmitter 29 (for example an encoder) provides a control loop for controlling the tool position relative to the main Z axis which can be displayed with the aid of a display device 28.

The position transmitter 29 is designed so that it has a predetermined Number of travel impulses per millimeter of travel along the main Z axis supplies.

To the control unit 20 for storing and processing the data a device 32 is also connected with which the positioning of the tool in the control axis X is controlled and the output

33
is connected to a comparison device. The latter is connected to a further comparison device 34. connected, namely via a transformer 35, which converts the positioning signals into speed signals, which are passed on to the motor 13, which causes the movements of the tool along the control axis X. A tachometer generator or an analog speed sensor generates

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Connection to the comparison device 34 is a control loop for control of the feed along the X-axis. A block 37 represents the integration of the speed of the motor and the actual position of the tool on the control axis X. A connected between the output of the integrator 37 and the comparison device 33 Position sensor 39 establishes a control loop for controlling the tool position on the control axis X, which is connected to the with the help of a Position transmitter "39 connected display device 38 are displayed can.

The output of the position sensor 29 is also connected to the input of a programmable digital divisor 40 connected, the output of which is connected to the input of a further programmable digital divisor 41 which is connected on the output side to a counter 42 will. This counter 42 is connected to the inputs of a programmable memory 43, for example an EPROM memory, the outputs of which are connected to a digital multiplier 44. at this device is specifically a "digital rate ■ multiplier", ie a digital speed multiplier, one input of which is connected to the output of the programmable digital divisor 40, while on the output side it is connected to a further, Multiplier 44, also designed as a digital speed multiplier, is connected, the output of which with a frequency / Voltage converter 46 is connected. The latter is finally connected to the comparison device 34. The output of the multiplier 45 is also connected to the input of the device designated 32, with which the positioning of the tool in relation to the control axis X is controlled.

In the memory 4 3, η (for example, 80) are values of ordinates or Ordinate increments of a standard curve are stored, which without taking correction factors into account, the elastic deformation of a any roller body approximately determined with predetermined dimensions. These ordinate or ordinate increment values can be for example, the values that are determined by using η equal and adjacent intervals on the abscissa axis η in-

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incremental ratio values of one half of an elastic deformation line can be specified as a model, this line without taking into account correction factors of the actual elastic - corresponds to the deformation of a roller body with given dimensions, as shown in Fig. 4, where, for a better understanding, the coordinates are denoted by the same identification letters X, Z as the machinery axes in Fig. 1.

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Because of the symmetrical curve of elastic deformation is this method of modeling the entire curvature with twice the number of intervals, i.e. with 160 intervals, equivalent if η is 80.

When the machine is in use, the operator can use the input unit 21 to enter the length L and the maximum deflection F required for the roller body To be given profile are characteristic, enter into the control unit 20.

Let us now assume that the position transmitter 29 gives 1600 pulses per millimeter Distance along the Z-axis. This means that the encoder has output 1600 x ζ pulses when the tool is in " a position with the coordinate ζ (in millimeters) to the Z-axis.

The programmable divisor 4 0 is programmed by the control unit 2 0 so that it is the number of the position transmitter / encoder 29 divides the pulses supplied by a number proportional to the length L which the operator has keyed in via the input unit 21; for example by the number L / 10. The default setting for this number takes place via three four-core cables designated by 50 Eins52 in FIG. As a result, the programmable divisor 40 then has 16,000 χ z / L pulses output when the tool is in position ζ of the main Z axis.

The programmable digital divisor 41 divides the number of pulses again, for example by 100, and thus gives 16Ox z / L pulses to the counter 42.

The position encoder / encoder 29 and the digital divisors 40,41 enable consequently the subdivision of the set distance L into the same number of intervals as that in the memory the stored reference curve has been created; that means in the present example in 160 intervals.

In fact, the digital divisor 41 always gives an impulse when the tool has covered a distance of ζ = L / 160. Analogue in addition the digital divisor 41 gives a second impulse after ζ = 2L / 160, and so forth.

The counter 42 counts the pulses output by the digital divisor 41. The sum formed by this counter 42 at any point in time can be used to determine at which of the 160 wecrintervals in which the distance L has been subdivided, the tool is currently located.

The counter 42 supplies the memory 43 with reference signals sum formed in each case, while the memory 43 in turn signals indicating the value of the ordinate or the ordinate increment in the outputs the respective assignment to the path interval at which the tool is currently located. The digital multiplier 44 multiplies the Number of pulses received from digital divisor 40 by a factor proportional to the value output from memory 43 Signals. The digital multiplier 45 then multiplies the pulses output by the digital multiplier 44 a second factor which is proportional to the value of the maximum deflection F which is keyed in by the operator via the input unit 21 became. This proportionality factor is determined by the control unit

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path describes, even if along the main axis Z in any position that does not necessarily have to correspond to one of the two end positions of the grinding path, a command is controlled to change direction.

With the grinding machine set up according to the invention, it is also possible to 'process' roll bodies which are not ground to a spherical shape, but rather should be given an inwardly curved profile, also according to a predetermined curve for inwardly curved profiles. In FIG. 6, a roller body 9' is shown. ^{1 shown} with such a concave profile, the profile 9 of the roller body being indicated with dashed lines before processing by the grinding machine.

The operator can control the machine via an on the input unit 21 Set the keyed command to execute a concave or convex profile. After this command input, the control unit gives 20 a "preset" command to the control block 47 via the line designated 70 (FIG. 5). Depending on whether the machine is for the Execution of a convex or concave profile is set on one half of the adjustment path along the axis Z (from the counter 42 information supplied), and depending on the information given along the Z axis Adjustment direction (information coming from position transmitter 29), control block 47 issues a "forward" or "backward" command to the device 32, via which the tool positioning is controlled in relation to the X axis in order to carry out the convex or concave profile.

The above statements with their special reference to the production a curvature profile corresponding to the bending line of the elastic deformation of the roller body also largely apply to other profiles with symmetrical or asymmetrical curvature. Analogous to the memory 43, a wide variety of other memory units can be used

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unit 20 and for example over two in Fig. 5 with 60 and 61 designated four-core cable and a three-core cable designated 62, so that in the present case the default a proportionality factor of a maximum of 499 is possible. The pulses emanating from the digital multiplier 45 are thus given for each Z-value of the movement or the movement increment, which must be executed by the tool along the control axis, to give the roller body the desired profile. The correspond-impulses are output from the device 32 with which the tool positioning is performed the control axis X controlled wildly. The frequency / voltage converter 46 converts the pulses output by the digital multiplier 45 into an analog signal that is used to control the speed of the motor 13 is used, which gives the tool the feed along the control axis X.

In the event that - as described above - the desired curvature profile of the roller body corresponds to its elastic deformation, which runs in a symmetrical curvature, only the values related to one half of the curve need to be entered into the memory 4 3 as described above. In this case, the counter 42 is designed as an up and down counter and is set in such a way that that it begins to count down when the number of pulses given by the digital divisor 41 indicates that the tool the vertex of the symmetry plane of the one in progress Roll body has exceeded.

The position transmitter 29 can expediently and in a conventional manner be set so that it also sends a warning signal emits in the direction in which the tool slide is along the main axis Z is currently moving. This signal is sent in a manner not shown in FIG. To the digital divisors 40 and 41, to the Counter 42 and passed on to the digital multiplier 44, 45, so that the tool always uses the same preset curvature grinding

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can be used, in each of which different relation curves for different tool profiles are stored. Such memories can be used with conventional switching devices on the grinding machine.

The grinding machine set up according to the invention can also perform other technologically interesting functions, such as compensating for grinding wheel wear during the Workpiece machining.

When machining workpieces, the grinding wheel is used proportionally ' the feed along the main axis Z äb.To compensate for this progressive wear, the device 32, with which the Tool positioning along the control axis X is controlled, pick up a further control signal, which corresponds to a from the operator pre-adjustable factor proportional to the adjustment path covered is. This signal, which is superimposed on the signal coming from the digital multiplier 45, allows the predetermined theoretical adjustment according to X with an adjustment path according to X in the direction of the 'workpiece, which is proportional to that carried out according to Z. Adjustment is to automatically compensate for grinding wheel wear.

The additional command for the wear compensation can be issued to the device 32 via an input unit (not shown) in the area of the additional inputs 32a to 32n. With the help of further input units (not shown), further signals can be controlled via these inputs, which make it possible to increase the depth feed of the tool by a certain amount whenever ^{a direction reversal occurs in the main axis 2} , in particular before the start of a new passage.

In the case of roller bodies which - as shown in FIGS. 2 and 6 - to the

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Ends have a conical collar, the Conical grinding work on these roller stumps with the inventive set up grinding machine can be carried out in a simple manner by using an input unit (not shown) on the Device 32, with which the tool positioning is controlled along the control axis X, the necessary control commands accordingly the feed rate and the direction of movement along the main axis Z. will.

Finally, the machine can with appropriate additional equipment without further ado for the automatic "short-stroking" operation, i.e. for short-stroke honing with down feed and constant movement reversal along the main axis Z if the contact pressure of the grinding wheel is too low and with the grinding wheel being withdrawn and trailing the same direction of movement along the main axis Z if the contact pressure of the grinding wheel is too high. This will be Avoided dead times that occur when the grinding wheel When machining a workpiece with a non-uniform profile during a grinding pass at certain points on the workpiece does not attack.

In the context of the asserted protection claim and in compliance with the basic principle according to the invention, details of the execution and use of the grinding machine can be varied as desired compared to the exemplary embodiment described here.

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Claims (8)

Expectations 1 ..) grinding machine with support means for a workpiece to be machined, with a verfahrba along a principal axis -. -Xgn tool carriage equipped with a grinding wheel, the iiwe'iner at right angles to the main axis Re - ν
gelachse_ is adjustable, with drive motors for - "moving the tool slide on the main axis and the grinding wheel on the control axis, as well as from an electronic control system that works with the drive s motors and controls the tool feed according to a predetermined path within the controls the main axis and the control axis defined movement plane for the execution of the desired workpiece profile, characterized in that the monitoring and control system contains the following main components: an input unit (21) for presetting the length (L) of the Tool slide path and thus the machining length of the Workpiece (9); a position encoder (29), which by appropriate signals the Indicates the position (z) of the tool slide (10) on the main axis (Z); Control units (40, 41, 42) which are connected to the position sensor (29) and are set up so that they are electrically Signals indicate at which point the same in η and COPY - 2 - The tool slide (10) is currently located; a storage unit (43) in which η denotes ordinates or ordinate increments of a reference curve (DE) in assignment are stored at the same, adjacent intervals of an abscissa axis, which are the path intervals of the slide path, while the reference curve (DE) represents the profile without taking correction factors into account, which is to be given to the workpiece, the storage unit (43) with the control units (40, 41, 42) is connected to signals for the display of the respective ordinate value in its assignment to the control units (40, 41, 42) _ to be able to output the specified path interval, and Converter (46, 32) for converting the signals output by the memory unit (4 3) into signals for controlling the dem The drive motor (13) assigned to the tool can be used with signals. 2. Grinding machine according to claim 1, characterized in that the input unit (21) is the presetting of a desired one Proportionality factor between the ordinates or ordinate increments the reference curve (DE) and the corresponding ordinates or ordinate increments of the desired workpiece profile enables. 3. Grinding machine according to claim 1 or 2, wherein the position encoder (29) an emits a predetermined number of pulses per unit length of the carriage path in the main axis Encoder is characterized in that the control units the following components include: a programmable digital divisor (40) which is connected to the encoder (29) and has means for presetting the Ratio between the number of input pulses and the number of output pulses is provided, this ratio can be set proportionally to the machining length (L) of the workpiece (9) with the aid of the input unit (21); COPY -3- a further programmable digital divisor (41) connected to the output of the first digital divisor (40) is and a counter (42) connected to the second digital divisor (41). 4. Grinding machine according to claim 3, characterized in that the storage unit (43) is connected to said counter (42) connected. 5. Grinding machine according to claim 4, characterized in that the converter consists of a digital multiplier (44) with Inputs for controlling the multiplication factor, which are connected to the corresponding outputs of the memory unit (4 3) are connected, and to a further input which is connected to the output of the first-mentioned digital divisor (40) and a frequency / voltage converter (46) connected to the digital multiplier (44). 6. Grinding machine according to claim 5, characterized in that between the frequency / voltage converter (46) and the Digital multiplier (44) · a further digital multiplier (45) is interposed. 7. Grinding machine according to one of the preceding claims, characterized in that it also has facilities (32) is to be provided, with the help of which the superposition of command signals of the adjustment position along the control axis (X) is possible to carry out additional functions, such as compensating for wear on the grinding wheel (12), incrementing the grinding infeed to the End points of the machining path, as well as short-stroke honing ("short-stroking" method). -4- -A- 8. Grinding machine according to one of the preceding claims, especially for arch grinding of roller bodies corresponding to the elastic bending line, characterized in that η Preset values of ordinates or ordinate increments of a reference curve (DE) are stored, the reference curve (DE) without taking correction factors into account represents the elastic bending line of a roller body.