MXPA99004972A - Tool for machining drill hole surfaces by chip removal - Google Patents

Abstract

Disclosed is a tool for machining workpiece surfaces, specially drill hole surfaces by chip removal, comprising at least two partial tools which can be displaced towards each other, wherein the work tool processing the workpiece surfaces can be rotationally moved. The tool is characterized in that is includes at least one control element (19) which can be displaced in a substantially perpendicular position to the rotational axis (9) of the tool in relation to the latter (1). Said control element causes one partial tool (5) to move in relation to the other partial tool (3), preferably when a given rotational speed is reached.

Description

TOOL FOR MACHINING SURFACES WITH PERFORATED HOLES The invention relates to a tool for machining surfaces of workpieces, especially surfaces with perforated holes, which has at least two partial tools that can be displaced relative to one another.

Tools of the type to which we refer are known. These are known as feedback or escape tools. The relative movement of the partial tools can be caused in several ways, for example by means of a control rod, an integral electric motor with or without gears, or with the help of the lubricant or the cooling solution. In conventional tools, the lubricant or the cooling solution move within a closed circuit, this means that they are used repeatedly. In such cases, it is impossible to exclude the possibility of impurities in the cooling solution passing into the tool and altering the function of the tool and / or the implementation of the relative movement of the two partial tools. The tools that have control bars or integral electric motors are very elaborate in their construction and large, and therefore expensive.

It is then an object of the invention to provide a tool of the type initially referred to that does not present these disadvantages, in other words, that it be of simple construction and functionally profitable.

To achieve this objective, a tool is proposed, which comprises the features specified in claim 1. In principle it is possible in the machining of surfaces with drilled holes, to use a fixed tool which is inserted in a hole drilled in a workpiece that rotates. In the tool proposed here, it is assumed that the tool for machining the machined surface can be rotated. The tool is characterized in that at least one control member is provided which can be moved substantially perpendicular to the axis of rotation of the tool, and can be displaced when the tool is rotating due to centrifugal forces. In this arrangement it is possible for the control member to move exactly radially, in other words, perpendicular to the axis of rotation. However, it is sufficient if at least one component of movement of the control member acts substantially perpendicular to the axis of rotation of the tool. As a result of the displacement of the control member, a relative movement of one partial tool relative to the other is effected -preferably from a limit speed of rotation which may be predetermined-. It is then apparent that the relative movement of the two partial tools can be effected only on the basis of the centrifugal forces that arise during the rotation of the tool. The tool proposed here is then very simple and free of faults in its construction, and can also be produced with effective costs.

A preferred example of embodiment of the tool is that which comprises a spring member which interacts with the control member. The spring member is designed in such a way that a predetermined restoring force is executed on the control member. If then the rotation speed falls below the pre-established limit, the relative movement of the partial tool relative to the other is carried out in the opposite direction.

Also preferred is an example mode of the tool where the control member interacts with a control means and causes a flow of this means in case there is a displacement within the tool. A hydraulic resistance is provided in the flow path of this medium, with the aid of which a uniform flow can be established. If the flow of the control means is influenced, it is possible to ensure a uniform movement of the control member.

Preference is also given to an example mode of the tool where the control member directly moves one partial tool relative to the other. The resulting construction here is particularly simple and is not susceptible to failures.

An example of a mode of the tool which is also preferred is that in which the control member carries out a displacement of the partial tool relative to the other by means of means, preferably by means of a fluid. The control member is then part of a hydraulic circuit which allows the movement of one partial tool relative to the other.

Finally, an example of tool mode in which the control member is part of an assembly unit which can be inserted into the tool is preferred. It is then possible to use assembly units with different characteristics, for example control members of different sizes or scales, throttles with several hydraulic resistances introduced in the hydraulic circuit and / or spring members with different restoring forces, in order to adapt the tool to different applications. In this way, the tool can be modified to cost-effectiveness.

In the sub-claims, additional modalities are presented.

The invention is explained in detail below with reference to the drawings, in which: Fig. 1 shows a longitudinal section through a first example of embodiment of a tool; Fig. 2 shows a cross section through the tool shown in Fig. 1 along the line II-II; Fig. 3 shows a longitudinal section through another example of a tool mode; Figs. 4 and 5 show a partial view of two additional examples of embodiment of a tool in longitudinal section and Fig. 6 shows a tool for the machining of valve seats and valve guides in a motor block of an internal combustion engine.

The tool 1 shown in Fig. 1 comprises two tool parts, specifically a first tool part 3 and a second tool part 5 movably positioned inside this tool. The first tool part is provided here by way of example with a cone 7 designed for example, as a hollow truncated cone which serves to secure the tool 1 for example, in a machine tool or in an adapter or connection piece. The tool 1 is caused to rotate in order to machine a workpiece surface or a perforated surface. The axis of rotation 9 is shown in dotted lines. In the base body 11 of the first tool part 3, a first recess 13 is provided, which extends, for example, concentrically to the axis of rotation 9, in which the second tool part 5 is displaceably accommodated. As shown herein, the relative movement of the second tool part 5 relative to the first tool part 3 extends substantially parallel to the axis of rotation 9.

The second tool part 5 has a piston device 15 at one of its ends, which - optionally with the use of a sealing device - is placed as a seal on the inner surface of the recess 13 and can be moved inside the recess. With a movement of the piston device, the second tool part 5 is displaced, performing a translational movement. In Fig. 1, the second tool part 5 or the piston device 15 is displaced fully to the left, so that the second tool part 5 is in an extended position. The length of the recess 13 is selected so that, in the event of an opposite movement of the second tool part 5 relative to the first tool part 3, to the right of Fig. 1, the exposed end 17 of the second tool part 5 can be introduced to a greater or lesser extent within the base body 11 and thus does not project beyond the external contour of the first tool part 3. It is only a question of equality length of the second tool part 5 to the length of the recess 13 so as to allow a greater or lesser extent of introduction of the second tool part 5. Due to this it is also possible to retract the second tool part completely inside the interior of the first tool part, so that the exposed end 17 does not project beyond the external contour of the first tool part 3.

At least one body that is used as control member 19 is inserted into the base body 11.

For example, two diametrically opposed control members 19 and 19 'are provided here. The control members are accommodated in secondary recesses 21 and 21 ', extended perpendicularly to the axis of rotation 9, whose dimensions are selected so that the control members 19 and 19' that this case is of cylindrical design for the purposes of the example, they are placed as a seal on the cylindrical interior surface of the recesses 21 and 21 '. It is further possible to provide sealing members 23 and 23 ', for example circular rings which are placed on the outer surface of the control members 19 and 19', and ensure an optimum seal. The control members 19 and 19 'are slidably positioned in the recesses 21 and 21'. Due to its weight or dead mass, the control members 19, 19 'are forced outwardly by means of the centrifugal force during a rotation of the tool 1. These therefore slide outwardly within the recesses 21, 21'. , until they hit against the covers 25, 25 'closing the recesses or against other means of retention.

The recesses 21, 21 'are filled with a medium, preferably with a fluid, especially a hydraulic oil, which in case of a displacement of the control members 19, 19' is forced out of the region of the recesses 21, 21 'which remains above the control members 19, 19', by means of a suitable connection path 27, 27 'indicated only in dotted lines in Fig. 1. The connection path connects the region of the recesses 21. 21 'which remains above the control members 19, 19', to the recess 13. The hydraulic oil is forced outwards by means of the control members 19, 19 ', in this way it passes to the recess 13. As a result of the superatmospheric pressure that is formed in the control members, the piston device 15, and with this the second part of the tool are displaced to the left in the case of a corresponding superatmospheric pressure.

The medium forced outwardly by means of the control members 19, 19 ', then serves here as a control means, which in the event that adequate superatmospheric pressure is present, effects an outward movement of the second tool part. 5 in relation to the first tool part 3. The control means is completely enclosed inside the tool 1 and in this case it is not in connection with other means that are used in the operation of the tool. In this way, the control means will be separated from the cooling liquids and the lubricants, so that the function of the control members is not affected by impurities that may exist in these media. This achieves a high degree of functional reliability.

At least one compensation chamber 29 in fluid connection with the recess 13 is inserted into the base body 11 of the first tool part 3 and is designed, for example, as a continuous annular space or comprises individual spaces. The fluid connection 31 between the compensation chamber 29 and the recess 13 serves to receive a forced medium out of the section of the recess 13 which is to the left of the piston device 15. For example, a gaseous medium can be introduced into the compensation chamber 19, which in the event of a movement to the left of the device of the piston 15, is forced by the fluid connection 31 to the compensation chamber 29 and compressed therein.

The compensated means serves as if it were a spring member, which executes a predeterminable restoring force on the piston device 15 and tends to force the latter towards the right, against the outward movement. As a result of the hydraulic coupling of the piston device 15 with the control members 19 and 19 ', the restoring force of the spring member, in other words of the compressed gas in the compensation chamber 29, also acts on the control members -19 and 19 '. The restoring force forces the piston device 15 to the right and thereby forms a superatmospheric pressure in the part of the recess 13 which is to the right of the piston device 15. By means of the connection path 27, this pressure is transmits to the top of the control members 19, 19 'so that the control members are forced radially inward toward the axis of rotation 9.

The gas present in the compensation chamber 29 may be under a certain superatmospheric pressure, so that a predetermined restoring force acts on the control member or members. In this case, the latter can perform a displacement only from a predetermined speed limit of rotation of the tool 1, thereby forcing the medium present above the control members 19, 19 'by means of the connection path 27 towards the right region of the recess 13.

The free space 33 or 33 'that lies below the control members 19 and 19' can be filled with gas which, via a suitable line, preferably provided with a filter device, is connected to the atmospheric pressure. It is ensured at least that any superatmospheric pressure prevailing in the region between the axes of rotation 9 and the bottom of the control members 19, 19 'is not high enough for the second tool part 5 to be displaced outwards without a rotation of the tool 1.

In Fig. 2 it is apparent that the connection path 27 has two partial paths 27a and 27b, or 27 'and 27'b, which are in fluid connection with the partial region radially outwardly of the recess 21 or 21 'and the work 13.

In the embodiment example shown here, the first path portion 27a or 27 'a is provided with a hydraulic resistance, designed as a throttle 35 or 35' and the partial path 27b, 27'b is provided with a return valve 37 or 37 '. As a result of this design, it is possible to affect the flow of the control means between the recesses 21, 21 'and the recess 13 that occurs in the event of a movement of the control members 19, 19'. Preferably it is provided that the throttles 35, 35 'act in case there is flow of the control means out of the recesses 21, 21' towards the recess 13 and with this there exists a uniform flow of the medium or an outward movement. of the second tool part 5 relative to the first tool part 3, while in the case of a movement in the opposite direction by means of the return valve, which is closed in the first case, a flow is ensured free out of the middle from the first recess to the recesses 21, 21 '. This outward flow ensures that the return movement of the second tool part 5 can take place if obstructed and quickly.

In case of an outward movement of the second tool part 5 as indicated above, the piston device 15 is displaced by means of the pressure formed in the control means or in the right part of the recess 13, so that the The medium present to the left of the piston device 15 is forced into the compensation chamber 29. Here, as a result of compression of the gaseous medium, an increase in superatmospheric pressure or an increase in the restoring force occurs. However, a uniform outward movement of the second tool part 5 occurs because in the case of an outward radial movement of the control members 19 and 19 ', high centrifugal forces are formed as a result of the increase in the distance from the axis of rotation 9. As a result of the larger forces which force the control members 19 and 19 'more and more strongly outward, the pressure on the control members 19 and 19' in the recesses 21, 21 ' , and therefore in the recess 13 also increases, which results in an increased force in the direction of the outward movement of the tool part 5.

Fig. 2 shows that the connection paths 27 or the connection paths 27a, 27b, 27 'and 27'b can be produced by means of holes drilled in the base body 11 of the first tool part 3 and that the throttles 35 and 35 'and the return valves 37, 37' are also inserted into corresponding perforated holes which intersect the perforated holes of the partial paths. The production form of the connection path 27 is well known, so there is no need to provide more details here. All that is essential is that the upper region or radially outward of the recesses 21 and 21 'be in fluid connection with the recess 13, so that in case of an inward and outward movement of the control members 19, 19 ', the control means can flow on one side from the recesses 21 and 21' towards the recess 13 and on the other side in the opposite direction.

In the modality shown here, the bottlenecks , 35 'and the return valves 37, 37' are accommodated in perforated holes which intersect the circumferential surface 39 of the tool 1 or of the tool part 3. This means that these assembly parts are accessible from the outside. It is also possible to design the bottlenecks in a variable manner and produce a hydraulic resistance that can be estahed. It is also conceivable to design the return valves so that they open and close at different pressure values. It is therefore possible to adapt tool 1 to different applications.

Fig. 3 shows a modified example of the mode of a tool 10, which is essentially identical in construction to that shown in Fig. 1. The same parts are provided with the same reference numbers, so this reference can be do for the description of Fig. 1.

The only difference in construction is in the compensation chamber 29 '. The longitudinal section through the tool 10 is taken here so that it extends below the axis of rotation 9 in a plane different from that which is above the axis of rotation. However, it should be emphasized here that two mutually opposite control members 19 and 19 'are also present in the tool 10, as explained with reference to Fig. 1. The compensation chamber 29' is positioned offset relative to the plane in FIG. which are the control members 19 and 19 ', but in this case the compensation chamber 29, has two sections, a section 29' a and a section 29 'b. One of the sections, in this case the section 29 'to the left, is connected by means of a fluid connection 31 to a region of the recess 13 which is placed to the left of the piston device 15. If then the piston device 15 or the second tool part 5 is displaced to the left by a superatmospheric pressure in the right part of the recess 13 based on centrifugal forces, the piston device 15 forces the means on its left by means of the fluid connection 31 to the section 29 'to the left of the compensation chamber 29'.

It can also be provided that a gaseous medium - which acts as a spring member - is present in the left section 29 'a. However, preference is given to a mode in which a fluid, for example hydraulic oil, is provided in the left section 29 'a, since this makes it easier to control sealing problems with the piston device 15 than in the case of a gaseous medium. To allow a movement of the piston device 15 to the left, in such a design, in other words when a fluid is used, a volume of gas acting as a spring member is provided in the right section 29 'b of the chamber of compensation and, in the case of a movement of the piston device 15 to the left, is compressed by the forced fluid to the compensation chamber 29 '. The left section 29 'a is separated from the right section 29' by means of a piston 41. This can also be part of a conventional gas pressure spring which comprises a volume of gas which is compressed by the forced fluid outwardly. by the piston device 15. The compensation chamber 29 'is in this case of cylindrical design. Its medial axis 43 extends substantially parallel to the axis of rotation 9. The tool 10 - like the tool 1 - can be provided with a cover that is removable, thereby allowing the replacement of the gas pressure spring. The embodiment example shown in FIG. 3 is characterized in that the piston device 15 can be subjected on both sides to the action of a liquid medium, especially hydraulic oil, the control means present to the right of the piston device interacts by means of the connection path 27 with the recesses 21, 21 'and therefore also with the control means 19, 19', while the oil present to the left of the piston device interacts with a spring member, example a gas pressure spring, which performs a restoring force on the piston device 15 and also on the control means 19, 19 '.

Fig. 4 shows a part of a further example of mode of a tool 100 having a first tool part 3 and a second tool part 5 that moves relative to the first. The tool 100 has a cone 7, which, as explained with reference to Fig. 1, serves to secure the tool and to propel it.

The second tool part 5 can be displaced, in the case of a rotation of the first tool part 3, in a substantially radial direction, in other words perpendicular to the axis of rotation 9. At least, a partial component of the movement of the Tool part extends in the radial direction. This tool part can be used for example to form grooves in surfaces with perforated holes and also for finishing.

The tool 100 has a control member 119 which is movably mounted in a recess 121 within the tool 100, extending perpendicularly to the axis of rotation 9. In the view shown in Fig. 4, the control member 119 is in its radially extended position.

The control member 119 interacts with a means, also described as a control means, in this case with a hydraulic oil. This is contained in a control chamber 147 which comprises two sections 147a and 147b mutually separated. The control chamber here surrounds the control member 119 in an annular manner. It is divided into the two sections 147a and 147b by means of an annular shoulder 149 extending from the control member 119. The sections 147a, 147b are in hydraulic connection with each other. A connecting path 127 between the two sections 147a and 147b has a first partial path 127a, in which there is provided a throttle 135 which acts as a hydraulic resistance, and also a partial path 127b, in which a return valve 137 is provided. The control chamber 147 is designed in such a way that in case of an outward radial movement of the control member 119, the control means is forced out of the radially outward section 147a of the control chamber 147 by means of of the connection path 127 towards the radially inwardly section 147b. The flow of the control means is influenced by the throttle 135 and by the return valve 137 so as to brake an outward radial movement of the control member 119 by the action of the throttle. An opposite movement inward of the control member 119 can be carried out without the throttling resistance, since in this case the return valve 137 is opened and the return of the control means from the section 147b to the section 147a of the Control chamber 147 is virtually unobstructed.

The control member 119 interacts with a control member 151 which exerts a restoring force on the control member 119 and is positioned at one end on a splice which is fixed relative to the control member 119 and at the other end on the control member 119. a splice which is formed by a closure cap 155 of the control member 1191. In this case the spring member 151 is accommodated within the control member 119. In FIG. 4, by way of example only, indicates as a helical spring; Here again, a conventional gas spring can be used as the spring member. This effects a restoring force which acts against the outward movement of the control member 119 and forces it towards its retracted position. As a result of the restoring force of the spring member 151, the control means, during a return movement of the control member 119, is conveyed from the section 147b by means of the return valve 137 to the section 147a of the chamber of control 147.

In the embodiment example shown in Fig. 4, the control member 119 extends beyond the axis of rotation 9 of the tool 100. This ensures that the center of gravity 5 of the control member 119, indicated herein, it is arranged at a distance from the axis of rotation 9, in this case above this axis of rotation. If then, the tool 100 is rotated, centrifugal forces act on the control member 119 and eventually a radial outward movement of the control member 119 is effected contrary to the action of the spring member 115.

The control member 119 is surrounded by an inner sleeve 157, which in this case forms the lower limit of the control chamber 147, and is surrounded by a second outer sleeve 159 which forms the outer boundary of the control chamber 147 In Fig. 4, a locking ring 161 is attached to the outer sleeve 159 at the top, limits the control chamber 147 at the top and can also be part of the upper sleeve 159. In the example shown here , the connection path 127 is in the form of a channel in the outer sleeve 159. Then, it is entirely possible that the connection path 127, the return valve and the throttling are accommodated in the interior or in the base body of the control member 119. This has the advantage that a very compact structural shape can be achieved.

The sealing ring lßl is sealed on the control member 119 and is designed to allow movement of the control member 119 relative to the closure ring and relative to the outer sleeve 159. The control member 119 is mounted so that it slides relative to the inner sleeve 157.

The sleeves and the closure ring are designed so as to receive the control member 119 and thus form an assembly unit 163 which can be inserted as a unit in the base body 11 of the tool 100. In this form, the Assembly unit is easy to replace. Such an assembly unit 163 can be inserted as a fully functional and separate unit into existing tools, so that they have a tool part driven by centrifugal force.

Furthermore it is entirely possible to design the assembly unit 163 of the control member 119 so that it is so small that -other than that shown in Fig. 4-it does not extend beyond the axis of rotation 9.

In the embodiment example shown here the second tool part 5 is provided in the region radially outwardly of the control member 119. This means that the second tool part 5 is fixed directly to the control member 119.

As a result of the coupling of the second tool part 5 to the control member 119, it is possible to move the second tool part 5 with respect to the first tool part 3. The displacement or relative movement of the two tool parts takes place as a function of the rotation speed of the tool 100 and the centrifugal forces acting on the control member 119, the flow of the control means takes place in the connection path 127 during the displacement of the control member 119, being influenced by the throttle 135 and by the return valve 137, which results in the reaction to the relative movement of the second tool 5. This executes a defined outward movement, as a result of the throttling action 135, preferably a uniform relative movement and slow. The inward movement that occurs when the speed of rotation of the tool is reduced, can be carried out rapidly under the action of the spring member 151 and due to the return valve 137.

Fig. 5 shows a part of a tool 100 which is substantially constructed as shown in Fig. 4. Identical parts with identical reference numbers are provided. Reference is then made to the description of Fig. 4.

The tool 100 has a first tool part 100 and a second tool part 5, which is again fixedly connected to a control member 119. The control member moves outward in the course of a rotation of the tool 1 preferably from a particular limiting rotation speed - as a result of which a control means, specifically hydraulic oil, is transported from a first section 147a by means of a connection path 127 to a second section 147b of a control chamber 147. If the rotational speed falls below the limit, the control member 119 is displaced backward by means of the spring member 151 ', or moved back towards the axis of rotation 9.

In the illustration according to Fig. 5, the control member 119 and therefore the second tool part 5 will be in their radially outward position, in other words, extended.

The spring member 151 here has a piston 165 which is fixed to the end of the control member 119 opposite the second tool part 5 and forms a restoring force which acts against the centrifugal force. To do this, the piston interacts with gas volume 167 which is enclosed between the piston a closing wall, which extends from the first sleeve 157, is placed between the piston 165 and the control member 119, and in a suitably, for example of a sealing device 171, secures a seal against pressure of the volume of gas 167. The volume of compressed gas 167 forces the piston 165 away from the axis of rotation 9. Since the piston 165 is connected by means of a connecting member 163 to the control member 119, the piston 165 moves the control member 119 in the same direction, so that the second tool part 5 in the control member 19 moves towards the axis of rotation 9. The spring member 151 then generates a resetting force which acts against the centrifugal force reached during a rotation of the tool 100. The restoring force is selected such that, from a velocity At a particular limit of rotation, the centrifugal force acting on the control member 119 is greater than the restoring force, such that a radial displacement is carried out outward from the center of gravity S of the control member 119, located at a distance of the axis of rotation 9. Then, the second tool part 5, also firmly connected to the control member 119, moves radially relative to the first tool part 3.

Again, in the embodiment example shown in Fig. 5, the sleeves 157 and 159 are provided, which surround the control member 119 and which, together with the locking ring 161, form an assembly unit 163. which can be replaced when necessary. Furthermore, it is possible to provide an assembly unit with hydraulic resistors or throttles 135 of different designs in order to influence the movement, especially the outward movement, of the second tool part 5. It is also possible to employ control members 119 of several dimensions such that the force acting outward during a rotation of the tool 100 can be adjusted to several applications of the tool. In addition, the assembly unit 163 can be designed so small that it does not extend beyond the axis of rotation 9.

In the embodiment example shown in Fig. 5, the connection path 127 with the partial paths 127a and 127b are connected together with the return valve 137 and the throttle 135 in the sleeve 159. However, here - as explained with reference to Fig. 4 - a displacement within the base body of the control member 119 is possible, such that a very compact structural form or assembly unit 163 is obtained.

It becomes apparent from the illustration in Fig. 5 that the spring member 151 can be taken as a gas pressure spring which compresses a volume of gas 167 under pressure. The gas pressure spring is placed under a removable cover 175, which means that the gas pressure spring can be accessed even in the assembled state of the assembly unit 163. It is also possible, using suitable known valve devices, set the gas volume pressure 167, and if appropriate, introduce gas in order to increase the desired pressure.

In view of the foregoing, it quickly becomes apparent that, in the type of tool explained with reference to Figs. 1 to 3, using the centrifugal force of rotation of the tool, an axial or relative displacement of the two tool parts 3 and 5 takes place substantially towards the axis of rotation 9. In contrast, in the tool 100 shown in Figs. 4 and 5 a radial displacement of the second tool part 5 relative to the first tool part 3 is provided as a result of the centrifugal force reached during the rotation of the tool.

Considering Figs. 1 to 5, it is obvious, that within a simple tool, both axial displacement and radial movement of the tool parts relative to one another can be achieved. It is also conceivable to take advantage of the radial displacement of a control member that is fixed to a tool part (see Figs 4 and 5) to move an additional tool part in the axial direction. For example, it is possible to connect the outward radial section 147a of the control chamber by means of a hydraulic connection path to a recess 13, as explained with reference to FIGS. 1 to 3. If, in such a structural form, a means of controlling the radially outwardly facing section 147a is forced outwardly during the outward movement of the radially moving control member 119, the control means passes through the connection path to the recess 13 and then makes an axial displacement of the second part of the tool, which was explained with reference to Figs. 1 to 3.

The path of the axial displacement of the tool part can be determined by the volume displaced by the control member, in other words, for example by the difference between the outer diameter of the annular shoulder 149 and the external diameter of the control member 119 and by the diameter of the recess 13. If a large volume of the control means is displaced by the control member, and the diameter of the recess 13 is relatively small, a relatively large axial displacement path of the tool part 5 of the tool 1 takes place. or 10, explained with reference to Figs. 1 to 3.

On the basis of the manner of operation of the tool, having two tool parts, it becomes apparent, that in addition to an axial displacement, which was explained with reference to Figs. 1 to 3, a displacement of a tool part at any desired angle with respect to the axis of rotation 9 of the tool 1 or 10 is simultaneously possible. It is also entirely possible, with the help of the control means displaced by a control member , extending a plurality of tool parts in various directions.

In all cases, it is ensured that the relative movement of the tool parts in one direction is influenced with the help of a hydraulic resistance or a throttle, so that a defined advance movement is generated which is as uniform as possible, while the reverse return movement can be carried out relatively quickly, due to a return valve, and a suitable spring member in this case generates appropriate restoring forces. - It is not decisive for the operation of the tool if the control member directly carries out a displacement of the second tool part, as explained with reference to Figs. 4 and 5, or if -as explained with reference to Figs. 1 to 3, or if a control means is interposed which transmits the movement of the control member or a control device based on the centrifugal force, the piston device produces a relative movement of the second part of the driven tool 5. by centrifugal force.

Resetting forces may act on the control member directly or be transmitted by means of a mechanical coupling or, as explained with reference in Figs. 1 to 3, hydraulic by means of a piston device towards the control member.

By selecting the mass of the control member or by placing its center of gravity relative to the axis of rotation of a tool, the centrifugal forces that are generated during a rotation of the tool can be established so that the forces applied by the control member they can be predetermined in order to move an element part of a tool. Since the control member interacts as a spring member, which directly or indirectly exerts a restoring force on the control member, a limiting rotation speed can be defined, the excess of which initiates a relative movement of the control member and at the same time of the associated tool part. The speed limit of rotation is after all relatively simple to predetermine. It is also possible to vary it with existing tools, for example using gas pressure springs whose pressure can be established from the outside.

It is common to all modeling examples that the control member can be displaced only on the basis of centrifugal forces, resulting in a relative movement of the two tool parts 3 and 5 based on the centrifugal forces, or a drive of the tool part 5 by centrifugal forces. The design of the tools is then very simple and therefore occurs with great cost effectiveness.

The movement of the tool parts with respect to each other can be exploited in the most varied applications. Consequently, it is not necessary for both tool parts to be used for machining. It is also conceivable that one of the tool parts be used only to guide the tool in relation to the workpiece to be machined or to support the second tool part.

It has been proven that the tool is particularly useful for the machining of valve seats and valve guides in the engine blocks of an internal combustion engine. Such tool is shown in Fig. 6. Fig. 6 shows tool 1, which has been explained in detail with reference to Figs. 1 and 2. Identical parts with identical number of references are provided. Therefore, reference will be made to the description of Figs. 1 and 2. Attached to the tool part 3 of the tool 1 is a special tool 200 which is in principle known. In what follows then, details will be given only of its essential parts and functions. The special tool has a first tool section 201, fixedly connected to the tool part 3, which can be rotated with the tool part 3 and provided on its circumferential surface 203 with at least one cutting plate 205 the which has a blade 207 pointing to the left which extends at an angle relative to the axis of rotation 9 and is used to machine the valve seat.

Within the tool section 201 there is provided a tool section 209 mounted to be movable in the direction of the axis of rotation 9 and which represents a valve cutting tool. The tool section 209 is coupled to the tool part 5, shown here in dotted lines, so that when the tool part 5 is displaced, a tool displacement 209 takes place. This, in this case, has on its surface circumferential a knife plate 211 which is used to machine the valve guide. It is possible to provide the tool sections 201 and 209 with one or more guide strips in order to guarantee the quality and dimensional conformity of the machined surfaces.

In Fig. 6, the region of the valve guide 213 and the valve seat 215 are indicated in dotted lines.

According to the illustration of Fig. 1, in which the tool part is shown in its extended position relative to the tool part 3, the tool section 209 is also extended relative to the tool section 201. of the special tool 200.

From the explanation notes of Fig. 6 it is inferred that the special tool 200 described in this case can be easily combined with a tool 10, which is described in detail with reference to Fig. 3.

The form of operation of the special tool 200, which serves to machine valve seats and guides in engine blocks of an internal combustion engine is in principle known. With regard to the manner of operation of this special tool and of the tool 1 or 10 shown with reference to Figs. 1 to 3, only the following will be discussed: During the machining of the valve seat, the tool 1, and also the special tool 200, rotates at a first speed of rotation which can be, for example, 1000 r.p.m. The centrifugal forces acting at this rotation speed on the control members 19 and 19 'which were explained in detail with reference to Figs. 1 to 3 are not sufficient to generate a sufficiently high pressure in the recess 13 so that the piston device 15 is displaced to the left. The restoring forces acting on the piston device 15 will then be so great that the second tool part 5, and likewise the tool section 209 are in their retracted position. With it the piston 15 will be - contrary to that illustrated in Figs. 1 and 3, displaced completely to the right, so that the second tool part 5 and the tool section 209 are placed in their retracted position.

After completing the machining of the valve seat 215, the tool 1 is slightly retracted so that the fully machined valve seat is no longer in contact with the first tool section 201 or with the blade 207. Now the rotational speed is increases enormously, for example at 4000 or 5000 rpm At this rotational speed, such high centrifugal forces act on the control members 19 and 19 'that the piston device 15 is displaced to the left against the pressure prevailing in the compensation chamber 29 or 29', as a result of the which the second tool part 5, and therefore the tool section 209, performs a movement relative to the first tool part and moves towards its extended position. As a result of the relative movement of the second tool part 5, the valve cutting tool or the tool section 209 moves towards the perframed hole which is used as the valve guide, the surface with perforated holes is machined for the guide valve 213. As a result of the bottlenecks described above with reference to Figs. 1 to 3 ensures that the advance movement is carried out uniformly. As soon as the valve guide has been fully machined, the speed of rotation of the tool is greatly reduced, so that the piston device 15 and with it the control members 19 and 19 'are retracted by the forces of restoration, so that the second tool part 5 or the tool section 209 will likewise be retracted and removed from the valve guide. As a result of the use of return valves, the return movement is much faster than the forward movement during machining of the valve guide surface.

From the explanations concerning the special tool 200 it is concluded that the tool 1 or 10 described with reference to Figs. 1 to 3 can be combined with conventional tools. It is also important that an axial displacement of a tool part relative to another tool part can be achieved in a simple manner, and centrifugal forces are only used to achieve relative movement. No additional control members are needed, for example the so-called control rods or motors incorporated in the tool, to generate the relative movement. The tool is then very weak and has low susceptibility to failure.

As a result of the combination of several movement trajectories in the axial and radial directions, many different tools can be produced, furthermore control members are used which perform both radial and axial relative movement. You can also achieve relative movements at any desired angle with respect to the axis of rotation of the tools.

From the function of the control members, it is obvious that the number of control members can be adapted to the application. In order to simplify the balance of the tools, three control members are preferably used, which are inserted into the base body of the tool at a uniform circumferential distance. However, as shown in Figs. 1 to 3, it is also obvious, that it is possible to effect a movement of two tool parts relative to one another with two control members or, as shown in the references of Figs. 4 and 5, merely to use a control member for such relative movement.

Claims (18)

1. A tool for machining surfaces of workpieces, especially for surfaces with perforated holes, which has at least two tool parts which can be moved relative to one another, the tool for machining the surface of parts of work is able to rotate, wherein at least one control member is provided, which is displaced relative to the tool substantially perpendicular to the axis of rotation of the tool, the control member, of the preset rotation speed limit, the movement of one part of the tool relative to the other, the control member interacts with a spring member which compresses the gas pressure spring, and exerts a predetermined and adjustable restoring force, contracting the centrifugal force on the control member.

2. The tool according to claim 1, wherein the control member interacts with the spring member which exerts a predetermined restoring force, contracts the centrifugal force, on the control member.

3. The tool according to claim 1 or 2, wherein the control member interacts with a control means, preferably with an oil, and causes a flow of the control means in case of a displacement with the tool.

4. The tool according to any of the preceding claims, wherein a hydraulic resistance (throttling) is provided in the flow path of the control means.

5. The tool according to any one of the preceding claims, wherein a return valve is provided in the flow path of the control means.

6. The tool according to any one of the preceding claims, wherein the spring member comprises a gas pressure spring.

7. The tool according to any one of the preceding claims, wherein the spring member acts on the control member directly or via a means, preferably a fluid.

8. The tool according to any of the preceding claims, wherein three control members are provided.

9. The tool according to any one of the preceding claims, wherein the control member carries out a displacement directly to one tool part relative to the other.

10. The tool according to any one of the preceding claims, wherein the control member carries out a displacement of one tool part relative to the other via a medium, preferably a fluid.

11. The tool according to any one of the preceding claims, wherein the control member interacts with a piston device which effects a displacement of one tool part relative to the other.

12. The tool according to any one of the preceding claims, wherein the piston device is subjected on one side to the action of the control means.

13. The tool according to any one of the preceding claims, wherein the piston device interacts on the other side with a spring member contracting the control means.

14. The tool according to any one of the preceding claims, wherein the control member is part of an assembly unit which can be inserted into the tool.

15. The tool according to any one of the preceding claims, wherein the control member is a body which moves under the action of a centrifugal force.

16. The use of the tool according to one of claims 1 to 15 for the machining of the valve seat and the valve guide within the engine of a fuel driven machine.

17. The use of the tool according to one of claims 1 to 15 for finishing.

18. An insert with a tool part for a tool, especially for a tool according to one of claims 1 to 15, comprising a control member which is movable under the action of external forces, especially of centrifugal forces, and used to move the tool part.