DE3019998A1 - DEVICE FOR CONTROLLING THE EXPANSION OF THE LAEPPING TOOL OF A LAEPPING MACHINE - Google Patents

Description

Act 80-10 / 20-34

Societe Anonyme Automobiles Citroen, 117 a 167, Quai Andre Citroen, 75747 Paris Cedex 15, France Automobiles Peugeot, 75, Avenue de la Grande - Army, 76116 Paris, France __ -

Device for controlling the expansion of the lapping tool a lapping machine.

Lapping machines are equipped with expandable lapping tools and have rotary and axial devices Displacement of the lapping tool, as well as facilities for controlling the expansion of the lapping tool.

The expandable lapping tools are very often provided with stones or diamonds that run along the surface lines. nes cylinder are arranged · and under the action a cone attached to an expansion rod can be moved in the radial direction. The expansion rod itself can be moved in the axial direction in the lapping tool » ί -.,: "" "

To move the expansion rod, various Devices are used. Very often this is an expansion bar connected to the piston rod of a hydraulic winch.

This hydraulic winch can be used in a classic way Activation of an electric slide can be controlled, the displacement of the piston of the Winds in one direction or the other, causing expansion or contraction of the lapping tool is effected.

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This electric slide can also be operated by a servo valve can be replaced, the actuation of which by a numerically programmed control via a stepper motor in Connection with a sensor for the displacement is effected.

Such a device is the same in, for example, French patent application no. 78 35720 Applicant described.

The surfaces produced by the lapping tool in this way are cylindrical, at least theoretically, because in practice the differences in thickness on the workpiece to be lapped cause the thinner one Divide the workpiece again after the lapping tool has passed under mechanical and / or thermal influences narrowed.

Often the result is the opposite of what was sought, particularly with regard to the cylinders of engines in which it is desirable that the diameter of the jacket should be larger than the diameter of the Side of the cylinder head.

DE-AS 1 045 841 discloses a device for controlling the expansion of the lapping tool of a lapping machine by means of a hydraulic winch described, which relates to the production of surfaces with a circular cross-section Allowed surface lines inclined or curved on the longitudinal axis. This device is of a type in which the

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Expansion of the lapping tool is caused by a cone that is frictionally engaged in the translation direction an expansion rod is connected, which itself frictionally with the piston of a hydraulic expansion winch is connected, the hydraulic expansion winch frictionally with the piston of a hydraulic Working thread is connected, through which the lapping tool in a translatory reciprocating motion is relocatable. The known device has a modulation device for modulating the volume of the Expansion winch, through which a modulation of the hydraulic pressure acting on this expansion winch can be achieved is. The modulation device has a translation direction movable control element, as well as a device for displacement driven by a cam of the movable control element as a function of the back and forth movement of the lapping tool.

The modulation device of the known device is formed by a hydraulic modulator, with a Cylinder that is hydraulically connected to the chamber of the hydraulic expansion winch, the volume of which during the expansion process is decreased. A movable piston is arranged in the cylinder, which is force-locked with a « Button is connected, which is controlled with the interposition of the cam.

However, the known device comprises a cam, which is frictionally connected to the fixed machine frame, and the hydraulic modulator is overall of a ^B Auteil

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wear, which is movably arranged in sliding guides and frictionally in the translation direction with the piston of the hydraulic working winch is connected. The play that may arise between the sliding guides and the component can occur affects the position of the feeler pin of the button. Furthermore, the due to the general warming of the machine, the expansions that occur affect the geometrical parameters of the machine. The known device therefore lacks sufficient accuracy; during the time Functional sequence, since the volume of the hydraulic circuit is sensitive to changes in the modulation pressure reacts depending on the clearance and thermal expansion.

The object on which the present invention is based was to provide a device for controlling the to create expansion of the lapping tool of a lapping machine of the type described above, in which the accuracy can be increased significantly.

This object is achieved according to the invention by that the modulation device frictionally with the Machine frame is connected, and that the cam frictionally with the piston of the hydraulic working winch connected and between a stopper connected to the cylinder of the working winch in the longitudinal direction and the movable control element of the modulation device is arranged.

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Since the modulation device and the cylinder of the hydraulic work winch are fixed, the position of the movable control element of this Modulation device solely through the Cams set. No game can affect this position. Even if between the rod of the piston If there is a clearance between the working winch and the cylinder of this winch, this clearance holds the cam floating, but without changing the position of the movable control element of the modulation device.

In an advantageous embodiment, the inventive Device on a pivotable lever around a fixed axis, which is between the cams and the movable control element of the modulation device is switched on. Through this pivotable Lever is prevented that forces that occur due to a longitudinal displacement of the cam, on transmit the movable control element of the modulation device. So this control moves in this way strictly in the direction of its axis.

The modulation device can be by a hydraulic Be formed modulator, as described for example in DE-AS 1 045 841.

In another embodiment, the modulation device has an electrical scanner that is a emits a modulated signal which is fed to an adapter which supplies a control signal to a comparator,

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which is also supplied with a signal indicating the position the expansion rod and the error signal emits, which acts on a control element of the expansion winch.

In the following, with reference to the accompanying drawings, two exemplary embodiments of a device according to FIG Invention explained in more detail.

Fig. 1 shows a schematic representation

first embodiment of a device

according to the invention;

Fig. 2 shows the working diagram of the lapping spindle j Fig. 3 shows the expansion diagram that would be obtained with a classic cylinder lapping

will;
Fig. 4 shows the expansion diagram with a

Expansion modulator with conical lapping

is obtained j
Fig. 5 shows in section a conical bore

and after lapping; FIGS. 6 to 10 show, in section, different bores,

which with a device according to the invention

can be obtained; 11 and 12 show two cams for producing the

Bores according to FIGS. 8 and 9j FIG. 13 schematically shows a second embodiment

a device according to the invention.

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In Fig, 1 the lower part of a lapping machine is shown, arranged on the one device for controlling the expansion of the lapping tool of this machine is, and there * has a working cylinder 1. In this cylinder a piston 2 is slidingly arranged, at the lower end of which the base body 3 of a lapping head is attached · A spindle 4, the is connected to a spindle 5 rotatably mounted in the piston 2, carries a lapping tool at its lower end 6th

The (basic body 3 of the lapping head has a winch 7 to control the expansion, the piston 8 is positively connected to a tube 9 through which the spindle 4 is passed. The pipe 9 is in a manner known per se and not shown in the drawing with a conical expansion rod connected so that it can move them axially. The rod 10 is otherwise with the spindle 4 so connected so that it can be set in rotation by this «

The winch 7 is connected via lines 11 and 12 to an electric »- Slider 13 connected, which the chamber of the winch with a pressurized fluid source P, not shown, or with a drain tank T can connect. the Line 12, which is with the lower, during the expansion process from is connected emptying chamber, has a throttle member 14, which the flow rate of the Fluid decreased and the lowering of the piston slowed down.

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During operation, the piston 2 is used for the lapping head issued an alternating back and forth movement, while the winch 7 is controlled by the electric slide 13 causes the displacement of the rod 10 to expand the lapping tool.

On a force-fit with the working piston 2 a related party Bracket 15 is attached to a cam 16, one surface 16 * of which is parallel to the axis of the cylinder 1 and the other surface 16 ″ has a profile that corresponds to the surface of the Workpiece corresponds. This cam 16 is in the direction of its height on the holder 15 with the aid of suitable Devices that can consist, for example, of a screw and a locking nut, adjustable attached.

The cam 16 rests between two rollers 17 and 18. The roller 17 is mounted on a cap attached to the working cylinder 1. The roller 18 is mounted on a lever 19 which can be pivoted about a fixed axis of rotation which is connected to the fixed machine frame in a force-locking manner. This lever 19 transmits the translation movement, which is produced by a displacement of the cam 16 in its longitudinal direction, to a hydraulic modulator 21 · This Moduldor sits down - sows from a a cylinder forming Kaner, which is force-fit "connected it to the fixed machine frame, and in which there is movably arranged a piston 22 which is in connection with the cam. the

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Chamber of the modulator 21 is via a line 23 with connected to the line 12, which opens into the lower section of the hydraulic expansion winch 7 from.

During the reciprocating movement of the spindle 4 transmits the cam 16 on the piston 22 of the modulator an alternating movement, due to which the volume of the lower chamber of the winch 7 and thus the one on the piston acting back pressure is varied.

This change in volume creates a proportional one Displacement of the expansion piston 8 and causes a Modulation of the expansion, its amplitude and speed change depending on the shape of the cam 16 used »

-In. Pig. ·.-2 are the η work cycles of spindle 4 with 24 shown, one duty cycle being a reciprocating motion corresponds to the spindle. The run of the spindle is thus shown as a function of time.

In Fig. 3, the entire expansion diagram of the lapping tool eye after η work cycles is shown at 25, namely with a cylinder lapping in which the modulator 21 is not present or is switched off. The diameter of the hole increases from the value A to the value A ¹ after η work cycles.

Fig. 4 shows the expansion diagram 26 of the lapping tool when the profile 16 "of the cam 16 is straight and oblique with respect to the axis of the cylinder

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arranged 1st. A conical lapping is obtained, the diameter of the lower part of the bore increasing from the value A to the value A ¹ , while the diameter of the upper part of the bore increases from the value B to the value B '(see FIG. 5), and the Diameters A and -A ^{1 are} smaller than the diameters B and B ^1, respectively.

The control device allows the generation of very different ver Profiles. For example, it is possible to drill holes in the form of an inverse cone (Fig. 6), a Double cone (Fig. 7), a diabolo (Fig. 8), a Ton (Fig.9) or a waist (Fig.10) to produce. For this purpose, it is sufficient to give the profile of the cam 16 a shape to give which corresponds to the shape of the desired hole. Figs. 11 and 12 show cams as an example 16a and 16b, with which holes according to FIGS. 9 and can be produced.

Fig. 13 shows an embodiment of a device to control the expansion of the lapping tool with an electro-hydraulic control circuit. On the winch a component is arranged which has a holder 27 on which a pulse-controlled stepper motor is attached. On the output shaft 29 of this motor there is a ball-bearing screw spindle 30 that slides fastened with wedges on which a nut 31 is mounted. This nut is supported by an arm or support 32 carried, which is positively connected to the tube 9 and thus to the piston 8. The core 33 of a

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Slides responsive sensor is positively connected to a sliding block 34, which on the Screw spindle 30 is arranged non-rotatably against this. The base body 35 of the sensor is on him supporting bracket 27 attached.

The measuring sensor 33 to 35 controls with the interposition an electronic timing chain, which will be described in more detail below, a servo valve 38, which is between the Lines 11 and 12 are switched on, which are connected to the winch 7 in such a way that the piston 8 moves in opposite directions Moves direction to the direction of displacement of the core 33 of the probe.

When the stepper motor 28 is put into operation, the ver shifts within the nut 31 in rotation Screw spindle 30 axially in one direction and thereby takes the core 33 of the probe with it. The error signal, which is supplied by the electronic timing chain, actuates the servo valve 38 such that the KoI ben 8 moves in the opposite direction, driving the expansion rod 10. Simultaneously the screw 31 moves axially while driving the screw spindle 30 and the sliding block 34, whereby the core 33 of the probe is guided towards its equilibrium position and the error signal is made to disappear.

It can be seen from this that when the stepper motor 28 is in operation is set, the piston 8 of the expansion winch shifts, and that when the engine is at a standstill

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Piston assumes a new position of equilibrium. An expansion is obtained depending on the direction of rotation of the motor or contraction of the lapping tool, the rate of expansion or contraction depends on the frequency of the control pulses fed to the stepper motor

The stepping motor 28 is via an amplifier 39 of a device 40 for numerical control of a known type, which has four inputs 41, 42, 43 and 44, which signals are fed to the the final dimension to be achieved, the working pressure, the torque transmitted to the lapping tool and one the necessary compensation due to the wear and tear of the lapping tool. These signals change within real times the basic program that is continuously supplied by the facility.

The sensor 33 to 35 is connected to one of the inputs of a comparator 45, while the other input a control signal 46 is fed to this comparator. The output of the comparator 45 is parallel to each other one of the inputs of two comparators 48 and 49 connected · The other input of the comparator 48 receives from 50 from a signal that corresponds to an upper threshold value "maxi" corresponds to, while the other input of the comparator receives a signal from 51 which has a lower threshold value "mini" corresponds to. The outputs of the comparators 49 and 49 are connected to the two inputs of an OR gate connected, the output of which is connected to a device 53 for generating a disturbance signal.

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The sensor 33 to 35 responsive to the displacement supplies a positive or negative signal, the amplitude of which is proportional to the displacement of its core 33 is. When this signal is different from the control signal supplied through the amplifier 61, a appears Error signal, / whose amplitude in normal operation between the two threshold values "mini" and "maxi" lies. If this amplitude is below the threshold value "mini" or is above the threshold value "maxi", the device generates 53 a malfunction signal and stops the numerical control device 40. This can be particular occur when the distance between the position of the movable core 33 and the position of the Piston 8 becomes too large, for example if the displacement of piston 8 does not occur because of the action acting on it hydraulic pressure has dropped.

The output of the comparator 45 is connected with the interposition of a differential amplifier 54 to the input of an alternating circuit 55 which is controlled by a set clockwork 56 which is switched on at the beginning of the working cycle. After a certain lengthy period of time, this clockwork causes the signal to pass to a device 63 for emitting a signal to purify the lapping tool. The two outputs of the circuit 55 are connected to the inputs of an OR gate. The output of the OR gate 57 is connected to the electric valve 38.

In this embodiment, the lever 19 actuates the is under the action of a return spring 58, an electrical Button 59. This supplies a modulated signal

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depending on the displacement of the cam 16 to an adapter 60, the comparator 45 a modulated Control signal supplies. The comparator 45 provides an error signal that is proportional to the instantaneous Deviation between the control signal and that continuously monitored by the sensor 35 Position signal is.

The adapter 60 is here with the comparator 45 over an operational amplifier 61 is connected, the output level of which is adjusted by a variable resistor 62 can be. This makes it possible to change the conicity of the bore without the cam 16 to have to replace.

Of course, variants of the above-described embodiments of the device are possible. So can in particular, the cam 16 have an angle with adjustable inclination ble, which also the conicity the bore obtained can be changed. Wei terhin the cam 16 can be fixed while the modulator 21 and its control lever 19 are positively connected to the movable part of the working winch 1 are.

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Claims (10)

DR. HEiNZ FEDER DR. WOLF-D. FEATHER PATENT LAWYERS
Dusseldorf Act 80-10 / 20-34 WP / Q Claims Device for controlling the expansion of the lapping tool of a lapping machine, in which the expansion of the lapping tool is effected by a cone which is positively connected in the translation direction to an expansion rod which is frictionally connected to the piston of a hydraulic expansion winch, the hydraulic expansion winch being non-positively connected is connected to the piston of a hydraulic working winch, by means of which the lapping tool can be set in a translatory back and forth movement, and which has a modulation device for modulating the volume of the expansion winch, by means of which a modulation of the hydraulic pressure acting on this expansion can be achieved The modulation device has a control element that can be moved in the translational direction, as well as a device, driven by a cam, for shifting the movable control element as a function of the back and forth movement of the lapping tool, characterized in that j 030050/0749 3019938 Act 80-10 / 20-34 - 2 - that the modulation device (18 to 22; 59) frictionally is connected to the machine frame, and that the cam (16) frictionally with the piston (2) the hydraulic working winch connected and between one with the cylinder (1) of the working winch in the longitudinal direction positively connected stop (17) and the movable control element (22) of the modulation before - ■ direction is arranged. 2. Device according to claim 1, characterized in that it has a lever (19) pivotable about a fixed axis (20) which is switched on between the cam (16) and the movable control element (20) of the modulation device. 3. Device according to claim 2, characterized in that the pivotable lever (19) is pressed against the cam (16) by a spring (58) supporting itself on it. 4. Device according to one of claims 1 to 3, characterized in that the stop (17) is a movable roller, the axis of rotation of which is arranged on a non-positively connected attachment to the cylinder (1) of the hydraulic working winch, and that the cam (16 ) is supported on the movable control element (22) of the modulation device with the interposition of a second roller (18), the axis of rotation of which runs parallel to the axis of rotation of the first roller. 030050/0749 Act 80-10 / 20-34 5. Device according to claims 2 and 4, characterized in that the axis of rotation of the second roller (18) is arranged on a projection which is non-positively connected to the pivotable lever (19). 6. Device according to one of claims 1 to 5, characterized in that the modulation device is formed in a manner known per se by a hydraulic modulator, with a cylinder (21) in which a movable piston (22) is arranged and the is hydraulically connected to the chamber of the hydraulic expansion winch (7), the volume of which is reduced during the expansion process, with either the cylinder (21) or the piston of the modulator being fixed, while the other component (22) is movable and with the interposition of the cam (16) is controlled. 7. Device according to one of claims 1 to 5, characterized in that the modulation device has an electrical button (59) which emits a modulated signal which is fed to an adapter (60) which supplies a control signal to a comparator (45) , which is also supplied with a signal which reflects the position of the expansion rod (9) and which emits an error signal which acts on a control element (38) of the expansion winch (7). 030060/0749 Act 80-10 / 20-34 8. Device according to claim 7, characterized by an amplifier (61) with a variable output level which is connected between the adapter (H) and the comparator (45). 9. Device according to one of claims 1 to 8, characterized in that the cam (16) is arranged to be adjustable in relation to the piston (2) of the hydraulic working winch. 10. Device according to one of claims 1 to 9, characterized in that the cam (16) has an angle with an adjustable pitch 030050/0749