JP2013533127A - Opposing device for grinding product held between centers - Google Patents

Abstract

A counter device for grinding a product such as, but not limited to, a cylinder held between centers, wherein a grinding machine (21) is a grinding wheel (24) facing a workpiece cylinder (22). The at least one opposing device (23) is disposed on the opposite side of the cylinder (22) with respect to the grinding wheel (24), and the opposing device (23) Has a slide (25) assembled to a short tube (26) that slides inside the main body (27) of the opposing device (23) by means of intervening actuators (28, 35), and is further short to the main body 27. A cylinder held between centers having a block element (29) relative to the tube (26) and an irreversible blocking device (31, 32, 33) in the position of the short tube (26) relative to the cylinder (22). Grinding products such as Opposite device for.
[Selection] Figure 1

Description

  The present invention relates to a product held between centers, in particular, but not exclusively, to an opposing device for grinding a cylinder.

  In general, in the field of cylindrical grinding, a particular area relates to the grinding of thin cylinders with a very small diameter / length ratio.

  In these cylinders, such as those used in laminators, two fundamental problems must be solved.

  The first problem is that during grinding, the grinding wheel must exert a thrust on the cylinder in order to perform its function. This thrust causes the cylinder itself to bend due to the elongated cylinder being processed, making it impossible to obtain a satisfactory geometry with respect to longitudinal section or roundness.

  The second problem lies in the fact that sometimes the combination of these forces, together with the thin shape of the cylinder, causes chattering between the grinding wheel and the cylinder, making the surface of the cylinder unacceptable. .

  These problems are typically addressed by attaching one or more opposing devices to the cylindrical support bench that apply a force to the cylinder that balances the force generated by the grinding wheel.

  The opposing device can be driven manually or automatically. In particular, the automatically driven counter device is assembled without discrimination on a manual or automatic cycle machine.

In view of the general problems described above, the objectives that these opposing device designers are trying to achieve can be specifically defined.
These purposes are generally as follows.

(A) Relatively small opposing force The opposing device must be able to apply a relatively small force on the cylinder, perhaps towards zero. When applying a much larger force to the cylinder compared to the grinding wheel, the opposing device deforms the cylinder in the opposite direction due to the fact that the opposing device and the grinding wheel are not always coplanar, This can cause the same problems that arise when only the grinding wheel is acting on the cylinder.

(B) Constant opposing force during the grinding cycle During the grinding cycle, the diameter of the cylinder decreases. Therefore, in order to maintain a constant opposing force throughout the grinding cycle, the position of the opposing device must be adjustable.

(C) High rigidity of the opposing device in the same direction as the forward path of the grinding wheel When the grinding wheel is in contact with the cylinder during grinding, the part being processed by the grinding wheel due to the shape error of the grinding wheel itself It can happen that the force applied to is dependent on its angular position. Specifically, this increase in force can cause the cylinder to bend. The opposing device must be able to counter these force gradients and prevent deformation of the cylinder.
The same phenomenon can also occur due to cylinder shape errors, especially in the initial grinding stage. Eccentricity and / or roundness errors can actually cause forces that tend to move the opposing device as in the case of grinding wheel shape errors. The opposing device must be able to resist these forces and prevent deformation of the cylinder.

(D) High degree of protection of the opposing device against the external environment The opposing device is a very precise mechanical or electromechanical device whatever it is. The opposing device also works in extreme environments. The grinding area in which these devices are located is actually contaminated by a portion of the metal removed from the grinding wheel debris and cylinder under the action of a cooling spray. Therefore, it is clear that the opposing device must be designed to assume sufficient measures to maintain the mechanism from the environment described above.

(E) Grindability of damaged cylinders in automatic mode Grinders must repair cylinders involved in lamination “accidents” very frequently. These cylinders are typically damaged to various extents and on various surfaces. Among these various surfaces can include surface, eccentricity, and roundness.
In this situation, in order to be able to grind in automatic mode, the opposing device must be sufficiently rigid so that the cylinder can be bent to “give” the desired shape.

  It should be pointed out that known counter devices cannot fulfill all of these objectives (a) to (e).

  With respect to the prior art, it should be noted that the above-mentioned counter device is generally composed of the following parts.

A slide on which a rotating cylindrical surface slides, the slide being made of a material having a low coefficient of friction;
A short tube that can move the slide towards or away from the cylinder by actuating the screw control; and
A short tube support structure fixed to a machine bench.

  Furthermore, known counter devices can be driven in two ways.

  Manual: In this case, the screw control is activated by turning the handle. By rotating the handle, the operator can adjust the opposing force applied to the cylinder by the slide.

  Automatic: In this case, a number of solutions have been tried, among which are rotation of screws driven by electric servo motors and rotation of screws driven by pneumatic servo motors. In any case, the system comprises a system that detects the establishment of either a force applied to the slide or a magnitude proportional thereto.

  As already pointed out, this state of the art has a series of challenges.

  For counter devices that are manually controlled, good results are obtained, but this possibility is inherently linked to the ability and experience of the operator. Furthermore, as already seen, the use of these devices is limited to grinding machines that function with a manual cycle.

  This situation changes fundamentally when the opposing device is controlled automatically. The traditional design of the known automatic device described above can actually only satisfactorily meet some of the above requirements (a) to (e). Despite repeated attempts, none of the solutions proposed so far can solve the problem of relatively small counter forces and constant counter forces during the grinding cycle.

  The reason why it is very difficult to achieve these two objectives is that, in essence, when the slide has to be moved, it adds to the inertia of the motor itself and the rotating and translating parts. Thus, in the fact that sufficient torque must be applied to the screw between the screw and the female screw and between the short tube and the guide to overcome the initial separation friction. Even though many solutions have been applied to limit the effects of this friction, the torque required to move the mechanism is much greater than the torque required to apply the opposing force, resulting in the mechanism being The force applied to the cylinder is generally greater than required. Furthermore, the screw translation mechanism is generally irreversible, and this force remains applied to the cylinder due to the need to have the support of the opposing device as rigid as possible. Thus, the force control system corrects the position of the slide so that this force is reduced and converged to the target value for subsequent approach.

  Therefore, the state-of-the-art automatic control system of the thrust to the cylinder of the slide is very complicated, and the vibration of the force around the target value is an unstable phase in the equilibrium state of the cylinder reflected in the surface defects of the cylinder itself. cause.

  In conclusion, it is known that the thinner the cylinder, the greater the problem of force stability.

  The overall object of the present invention is to solve the above-mentioned drawbacks of the prior art in a very simple, economical and particularly functional manner.

  It is a further object of the present invention to provide a grinding counter apparatus that meets all five of the above-mentioned objectives, particularly but not limited to a cylinder held between centers.

  Yet another object of the present invention is to provide a cylindrical grinding counter unit held between centers suitable for both manual and automatic cycle grinders.

  In view of the above objects, according to the present invention, an opposing device has been devised for grinding a cylinder held between centers having the features described in the main claim and the appended dependent claims.

  The structural and functional features of the present invention and its advantages over the prior art, in particular, show an exemplary embodiment of a counter device for grinding a cylinder held between centers manufactured according to the same invention. It will become more apparent from the following description with reference to the schematic drawings.

It is an expansion schematic sectional side view of the cylindrical grinding machine provided with the opposing apparatus by this invention. FIG. 2 is a schematic top view showing attachment of several devices shown in FIG. 1. It is an elevational view by the arrow F in FIG. It is an expansion schematic sectional drawing of the opposing apparatus in a non-operation position for grinding the cylinder hold | maintained between the centers shown in FIG. FIG. 5 shows several operational steps of the opposing device according to the invention as shown in FIG. FIG. 5 shows several operational steps of the opposing device according to the invention as shown in FIG. FIG. 5 shows several operational steps of the opposing device according to the invention as shown in FIG. FIG. 5 shows several operational steps of the opposing device according to the invention as shown in FIG. FIG. 5 shows several operational steps of the opposing device according to the invention as shown in FIG. FIG. 5 shows several operational steps of the opposing device according to the invention as shown in FIG. FIG. 5 shows several operational steps of the opposing device according to the invention as shown in FIG. FIG. 5 shows several operational steps of the opposing device according to the invention as shown in FIG.

  With reference to FIGS. 1-4, these show an exemplary application of a counter device for grinding a cylinder held between centers. In particular, it can be seen that a so-called thin cylinder 22 (very small diameter / length ratio) is arranged in the holding structure 20 of the grinding machine 21. At least one counter device 23 according to the present invention is located between the centers of the grinding machines, and further to the holding structure 20 on the opposite side of the cylinder 22 with respect to the grinding wheel 24 fixed to the holding structure 20. It is fixed. FIG. 2 shows how several opposing devices 23 are applied which all act on the cylinder 22 on the opposite side of the grinding wheel 24 at the same time.

  The counter device 23 according to the invention comprises a slide 25 which is made of a material having a low coefficient of friction and slides against a cylinder 22 being processed, as better shown in FIGS.

  The slide 25 is assembled to a short tube 26 that slides inside the main body 27 of the opposing device 23. The fit between the body 27 and the short tube 26 is protected at the front by a flexible expandable bellows 28 which is sealed and constrained to both parts. The bellows 28 surrounds one end of the short tube 26 and is restrained by the main body 27 and the short tube 26 at both ends thereof.

  A block piston 29 that blocks the relative position of the short pipe 26 with respect to the main body 27 is also assumed. The piston 29 is of a single action type, for example, and is arranged in a normal direction with respect to the longitudinal axis 30 of the opposing device 23.

  The piston 29 exerts a force perpendicular to the axis 30 of the short tube 26 sufficient to ensure axial fixation due to the generated friction.

  Finally, the screw 31 is assembled to the rear part of the main body 27 of the opposing device 23 and rotates inside the screw die 32 integrated with the main body 27. The screw 31 is actuated by a motor 33 and functions as an irreversible blocking means for the position of the short tube 26 with respect to the cylinder 22.

  For this purpose, the shaft of the motor 33 and the screw 31 are connected by a joint that transmits torque and allows bidirectional axial sliding.

  The free end of the screw 31 on the opposite side of the motor 33 contacts the bottom of the short tube 26.

  The control system 34 of the opposing device 23 supplies pressurized air to the expandable chamber 35 defined by the bellows 28 and the outer surface of the short tube 26.

  4 to 12, the opposing device according to the invention functions according to the following method.

  In the first stage, when the cylinder 22 is assembled between the centers C, the slide 25 moves from the position of FIG. 4 to the position of FIG.

  To do this, the control system 34 of the opposing device 23 sends pressurized air into the chamber 35 defined by the bellows 28 and the outer surface of the short tube 26. As a result of this pressure, the bellows 28 constrained by the body 27 of the opposing device 23 can only extend in one direction and pull the short tube 26 and consequently the slide 25. When the slide 25 reaches the surface of the cylinder 22 being processed, it exerts a greater force than required due to the mass inertia of the short tube 26 and the mass inertia of the slide 25. There is nothing to limit the movement of the slide 25 in the opposite direction, but the force stabilizes immediately after the impact at a value equal to the air pressure on the annular surface defined by the bellows 28 and the short tube 26. This air pressure can be determined as needed by varying one or both of these parameters.

  Thus, the first object (object a) described above, which is a relatively small opposing force, is effectively achieved.

  Furthermore, the air pressure in the annular chamber 35 defined by the bellows 28 creates a slight pressurization in the system that guarantees the mechanism from contamination by particulate matter coming from the external environment, and thus the high pressure of the device against the external environment. The purpose of the degree of protection (purpose d) is also achieved.

  After reaching this position and condition, the pneumatic cylinder 29 is actuated to release its force to the short tube 26, thus providing a braking force (FIG. 6). The braking force depends on the coefficient of friction between the piston of the cylinder 29 and the short tube 26, which is also required at the design stage by affecting the supply pressure, the cylinder diameter, or both. Can be determined according to

  At this point, the screw 31 is actuated by the motor 33 (FIG. 7), and advances inside the screw die 32 while feeding the head of the screw itself to the end of the short tube 26. Since the short pipe 26 has already been braked, the position of the slide 25 does not change, and the force applied to the cylinder 22 by the slide 25 does not change. At the same time, the new position of the screw 31 ensures that the position of the short tube 26 is fixed.

  In this way, the high rigidity (object c) of the opposing device is also achieved.

  Thus, grinding is achieved with excellent performance and results in the cylinder being machined.

  It is also clear that the opposing force produced by one or more slides 25 should be reconstructed each time the grinding wheel 24 reaches the moving end and consequently no longer applies pressure to the cylinder 22. Otherwise, due to the reduced diameter of the ground cylinder, this force will gradually decrease to zero.

  For this purpose, pressure is removed from the chamber of the pneumatic cylinder 29. As described above, the bellows 28 further receives air and presses the short tube 26 and the slide 25 against the cylinder 22 that has been processed again (FIG. 8).

  As already pointed out, after a very short period of time, the pressure in the chamber 35 between the bellows 28 and the short tube 26 stabilizes and the pneumatic brake can be blocked again. That is, the piston of the cylinder 29 can re-engage with the short tube 26 (FIG. 9).

  Finally, the conclusion already mentioned is that the screw 31 is actuated again to ensure irreversibility of the position of the short tube 26 (FIG. 10).

  In this way, the high rigidity objective of the opposing device 23 is again achieved, and as a result, it can be said that the opposing force remains substantially constant over the entire grinding cycle.

  Thus, the opposing device according to the present invention achieves the overall objective described above.

  With this device it is also possible to machine damaged cylinders on the grinding machine.

  When the cylinder 22 is arranged between the centers, it actually proceeds as in the above example, and the control system 34 of the opposing device 23 pressurizes the chamber 25 between the bellows 28 and the short tube 26. Bring in air. The situation described above in which the slide moves towards the cylinder is obtained (FIG. 11).

  The force is thus stabilized at a specific target value defined by the annular surface and the supply pressure.

  At this point, the screw 31 is actuated by a motor 33 to feed its own head against the end of the short tube 26. Because the short tube 26 is not damped, the screw 31 can apply a force to the slide 25 that is related to the torque applied to the control of the screw 31. If this force is sufficiently large, the cylinder 22 can be bent and held in that position due to the irreversibility of the movement of the screw 31 (FIG. 12).

  In this way, the remaining object (object e) described above, which enables grinding of a damaged cylinder, is also achieved.

  Naturally, the value of this force can be adjusted as required by the torque applied to the screw 31.

  Therefore, the purpose stated in the preamble of the description has been achieved.

  The opposing device according to the invention is particularly appreciated in fully automated plants where the operator can control the device in the control room and as a result is completely isolated from the surrounding contaminated environment.

  The form of the structure for making the opposing device 23 of the present invention, as well as the materials and assembly methods, can of course differ from those shown in the drawings for purely exemplary and non-limiting purposes.

  Accordingly, the protection scope of the invention is defined by the appended claims.

Claims (7)

A counter device for grinding a product such as a cylinder held between centers,
The grinding machine (21) has a holding structure (20) with a grinding wheel (24) facing the work cylinder (22),
At least one opposing device (23) is disposed on the opposite side of the cylinder (22) to the grinding wheel (24);
The counter device (23) has a slide (25) assembled to a short tube (26) that slides inside the main body (27) of the counter device (23) by an intervening actuator (28, 35), and A block element (29) in the position of the short pipe (26) relative to the main body 27 and an irreversible block device (31, 32, 33) in the position of the short pipe (26) relative to the cylinder (22).
Opposing device for grinding products such as cylinders held between centers.   The opposing device according to claim 1, characterized in that the block element (29) is a piston.   The intervening actuator surrounds the tip of the short pipe (26) and is defined by an expandable annular shape defined by bellows (28) fixed at both ends to the short pipe (26) and the body (27) of the apparatus. 2. Opposing device according to claim 1, characterized in that it consists of a chamber (35), which is connected to the control system (34) of this opposing device (23).   The block piston (29) at the position of the short pipe (26) relative to the main body (27) is a single action type, and is in a normal direction with respect to the longitudinal axis (30) of the opposing device (23). The opposing device according to claim 1, wherein the opposing device is arranged.   The irreversible block device at the position of the short pipe (26) with respect to the cylinder (22) includes a screw (31) that rotates inside a screw die (32) integral with the rear end of the main body (27). The counter device according to any one of claims 1 to 4, wherein (31) is operated by a motor (33) and contacts the bottom of the short pipe (26).   6. The facing device according to claim 1, wherein the slide is made of a material having a low friction coefficient.   7. The facing device according to claim 1, wherein a certain number of the facing devices are arranged on the opposite side of the grinding wheel (24).

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