Grinding tool, machine tool, and cutting fluid

Abstract

The invention relates to a comminution tool (12) for comminuting rock (32) by means of pressure waves (48, 52) in a cutting fluid (20), wherein the comminution tool (12) has a housing (34) with a working opening (66), wherein cutting fluid (20) is located in the housing (34) and / or wherein the comminution tool (12) has an inlet (24) for cutting fluid (20), wherein rock (32) to be comminuted can be approached to the working opening (66) for comminution and / or introduced into it, and the comminution tool (12) has an actuator (46) for generating a pressure wave (48, 52) in the cutting fluid (20). The invention further relates to a machine tool (10) and a cutting fluid (20). They enable particularly low-wear comminution of rock (32).

Description

[0001] The invention relates to devices for crushing rock using pressure waves. Such devices have gained some notoriety in the medical field, for example, in the form of kidney stone lithotripters. In these devices, a person to be treated is positioned in a tub filled with water. Extracorporeal pressure waves are generated, which then, for example, shatter a kidney stone located within the person.

[0002] However, such kidney stone lithotripters cannot be used to crush, cut, or drill rock on construction sites, such as concrete ceilings, walls, or floors. This is not possible because the ceilings, walls, or floors cannot be placed in a water-filled tub like the person.

[0003] Kidney stones also differ from concrete, for example, in their fracture strength.

[0004] To date, rotary-driven drill bits, such as hammer drills, diamond drill bits, or circular saw blades, have been used for drilling or sawing rock on construction sites. However, these are naturally subject to significant wear.

[0005] The object of the present invention is therefore to offer low-wear devices or aids for crushing, in particular for drilling or sawing, rock on construction sites, in particular building construction sites or civil engineering construction sites.

[0006] The task is first solved by a shredding toolfor crushing rock by means of pressure waves in a cutting fluid. Cutting fluid can be located in the housing. Alternatively or additionally, the crushing tool can have an inlet for cutting fluid. Cutting fluid can be filled into the housing through the inlet. The crushing tool has an actuator for generating a pressure wave in the cutting fluid. The pressure wave can generate cavitations in the cutting fluid and / or at an interface of the cutting fluid. The housing can have a working opening. Rock to be crushed can be brought close to the working opening for crushing and / or introduced into it. In particular, with the aid of the actuator, the cutting fluid can be conditioned in such a way that the rock is crushed upon contact with the cutting fluid. The cavitations can crush the rock or contribute to the crushing process.In addition, cavitations can reach pressures that can exceed the amplitude of the pressure wave that triggered them.

[0007] One aspect of the invention is that a housing is provided. The housing can be placed with its working opening against the rock to be crushed. Alternatively, transportable rock can be brought to the working opening. A crushing process can be started in both cases. In particular, pressure waves can be generated with the help of the actuator. The rock can be crushed by the pressure waves. A trough into which the rock would have to be placed is therefore no longer absolutely necessary to crush the rock. The rock can ultimately be crushed by contactless energy input. Wear of a tool part, for example the tip of a steel chisel, due to contact abrasion is therefore fundamentally excluded. The crushing tool can therefore be used with particularly low wear.

[0008] The actuator can comprise a piezoelectric element for generating the pressure wave. Alternatively or additionally, it can comprise a magnetic element for generating the pressure wave. It would also be conceivable to generate the pressure wave using a thermal pulse. For example, the actuator can comprise an arc generator to generate an arc, in particular an arc pulse, that locally heats water at high speed. For this purpose, it is also conceivable for the actuator to comprise at least one laser.

[0009] The actuator can also comprise multiple actuator parts, each of which is individually configured to generate a pressure wave. The actuator parts can, for example, be arranged parabolically. A resulting pressure wave composed of the individual pressure waves of the individual actuator parts can have a particularly high amplitude.

[0010] The pressure wave may comprise one or more pulses. Alternatively or additionally, the pressure wave may also comprise multi-period waves, for example, sinusoidal waves.

[0011] The shredding tool can be portable. It can weigh less than 10 kg, for example, or less than 3 kg. This allows construction workers to work on walls or ceilings without any particular health risks or premature fatigue due to excessive loads.

[0012] The comminution tool can be designed as a drilling tool or a sawing tool. In particular, as a drilling tool, it can be configured to create blind holes or through-holes with a circular and / or freely selectable cross-section in the rock through rock comminution. As a sawing tool, it can be configured to make separating cuts in the rock.

[0013] Our own studies have shown that, depending on the type of rock, cavitation can only be crushed at a mining speed relevant for construction sites if it reaches a certain minimum power density. The minimum power density, in turn, depends on the actuator's power. It is therefore advantageous if the actuator has a continuous mechanical power of at least 0.5 kW, especially at least 1 kW, for crushing concrete, for example. The continuous mechanical power can be measured, for example, as the average power over a period of 1 hour.

[0014] The comminution tool can have a focuser for focusing the pressure wave on a focal area to increase the power density in the focal area. The focuser also enables the use of larger actuators, which in turn enable higher continuous power outputs. The focuser can have a curved surface. For example, it can be in the shape of a parabolic mirror. It can be designed to deflect pressure waves by more than 45 degrees, for example, by 80 to 90 degrees, and / or be aligned accordingly within the housing and / or accordingly relative to the actuator.

[0015] The comminution tool may have an adjustment device for adjusting the focus area. In particular, its position, size, and / or orientation may be adjustable. The adjustment device may act on the actuator and / or the focuser. The adjustment device may be configured to displace, rotate, and / or deform the actuator and / or the focuser, in particular relative to the working opening.

[0016] The comminution tool can be configured to automatically regulate comminution performance. For this purpose, the comminution tool can be configured to automatically adjust the focus range. For this purpose, the comminution tool can have a distance meter. The distance meter can comprise an optical distance meter. Particularly preferably, the distance meter can also detect distances mechanically, for example with the aid of a probe. In a further preferred embodiment, the distance meter can be configured to measure distances based on transit time. For example, the transit time of a pressure wave generated by the actuator can be measured until it impacts the rock and / or until it is reflected back and reaches the actuator again.

[0017] In particular, a distance from the focus area to a rock surface, for example, to a position on the rock to be processed, can be measured. It is also conceivable to measure a distance between the actuator and / or the focuser to the focus area and / or the rock surface.

[0018] The shredding performance can be automatically controlled based on one or more of the distances.

[0019] It is also conceivable to analyze the cutting fluid, particularly the particles contained therein. For example, particle density, particle size, particle shape, particle quantity, and / or particle type, such as the material type of particles contained in the drilling fluid, can be measured. Alternatively or additionally, it is conceivable to automatically regulate the comminution performance based on such an analysis of the cutting fluid.

[0020] The control can be based on a feedback loop. For example, the focus range setting can be varied within the feedback loop to achieve optimum mining performance and / or the geometry of the crushing tool-rock arrangement.

[0021] The comminution tool may include a fluid management system. The fluid management system may have at least one pump for pumping the cutting fluid. The comminution performance can also be influenced by regulating the pump's pumping power.

[0022] The fluid management system can be configured to purify the cutting fluid to reduce fluid consumption. For this purpose, it can include a filter for purifying the cutting fluid. The filter can, for example, comprise a particulate filter.

[0023] The fluid management system can also be configured to control the composition of the cutting fluid. If the cutting fluid comprises multiple components, the fluid management system can, for example, be configured to stabilize the mixing ratio of the components to one another and, for this purpose, to add or separate a specific amount of a component as needed.

[0024] The fluid management system can also include a suction device. This can be used to extract escaping cutting fluid and, for example, return it to a normal circulation system and / or dispose of it.

[0025] A seal may be formed and / or arranged at an edge of the working opening. The seal can reduce or prevent fluid loss due to the escape of cutting fluid along the edge of the working opening.

[0026] It is also conceivable for the housing to have vibration damping to prevent vibrations generated within the housing, for example, those caused by the pressure wave, from escaping to the outside, or to do so only in a damped manner. This can be particularly advantageous for high-performance actuators, such as those described above. It is conceivable for a damping layer, for example made of an elastic material, to be applied to the housing. Alternatively or additionally, the actuator can be vibrationally separated from the housing using a vibration-damping intermediate layer, or at least arranged in a vibration-damping manner.

[0027] The scope of the invention also includes a machine tool,comprising a tool holder configured to receive a comminution tool of the type described above and in the following. The comminution tool can be received in the tool holder of the machine tool. The tool holder can be configured to establish a tool-free, detachable connection to the comminution tool. For this purpose, it can, for example, have a locking mechanism.

[0028] The machine tool may include a fluid reservoir for storing cutting fluid. It may include a fluid connection that is connectable to the inlet of the comminution tool or is connected when the comminution tool is mounted in the tool holder.

[0029] It is also conceivable for the machine tool to alternatively or additionally have a fluid management system. The fluid management system can have one or more of the features of the previously described fluid management system of the comminution tool. This eliminates the need for a fluid management system in the comminution tool. The comminution tool can therefore be manufactured smaller and more cost-effectively. The fluid management system can be or can be supplied with energy by a power supply, for example, a rechargeable battery, of the machine tool.

[0030] The tool holder can be located on an arm that is adjustable in at least one dimension. Preferably, the at least one dimension is motor-adjustable. This offers the possibility of carving out a greater variety of contours in the rock. The arm can comprise at least one linear drive and / or a rotary drive. If, for example, the arm has at least two dimensions in which it is adjustable, at least two-dimensional contours can be formed, for example by sawing, drilling or milling. In particular, and especially with an arm that is adjustable in at least three dimensions, undercuts can be formed.

[0031] The scope of the invention also includes a Cutting fluid for a comminution tool of the type described above and further below. The cutting fluid can be designed in particular for comminution of rock by means of cavitation.

[0032] A low-cost, easy-to-manufacture cutting fluid may comprise a single fluid component.

[0033] A cutting fluid comprising more than one fluid component may exhibit improved cavitation performance.

[0034] A readily available and cost-effective liquid component, usually even available locally, can be water.

[0035] A class of cutting fluids may include a fluid component that has a lower vapor pressure than water under standard conditions and / or a lower vaporization temperature than water at an ambient pressure of 101,325 Pa. Such a fluid component may be configured to form cavitations under less restrictive conditions than water, for example, at lower negative pressures or at lower temperatures than water.

[0036] It is particularly conceivable that one liquid component is hydrophobic and that the cutting fluid contains at least one component other than water. The hydrophobic liquid component and the water can then be separated from one another relatively easily. For example, the cutting fluid can be refreshed or conditioned particularly easily within the fluid management system. Bubbles of the hydrophobic liquid component can form in the cutting fluid, particularly near the focus area or in the focussing area. The pressure wave can be transmitted from the actuator to the bubbles via the water. If the hydrophobic liquid component has a high tendency to cavitation, cavitations can be specifically generated within or by the bubbles. This also makes it particularly effective to control the areas in which the rock is crushed.

[0037] Further features and advantages of the invention will become apparent from the following detailed description of exemplary embodiments of the invention, based on the figures of the drawing, which show details essential to the invention, and from the claims. The features shown therein are not necessarily to scale and are presented in such a way that the special features of the invention can be clearly seen. The various features can be implemented individually or in combinations in variants of the invention.

[0038] The schematic drawing shows embodiments of the invention and explains them in more detail in the following description.

[0039] They show: Fig. 1 a machine tool with a crushing tool on a rock in a schematic representation; Fig. 2 the crushing tool from Fig. 1 in a schematic, enlarged representation.

[0040] In the following description of the figures, the same reference numerals are used for identical or functionally corresponding elements to facilitate understanding of the invention.

[0041] Fig. 1 shows a machine tool 10 with a shredding tool 12 in a schematic representation. In this exemplary embodiment, the comminution tool 12 is designed as a drilling tool. For this purpose, as explained in more detail below, it is configured to drill blind holes or through holes in rock.

[0042] The crushing tool 12 is in a tool holder 14 the machine tool 10.

[0043] The tool holder 14 sits on an arm 16 of the machine tool 10. The arm 16 is designed as an XY table. It enables movements as indicated by a dotted arrow 17 in Fig. 1indicated, in vertical direction within the image plane of the Fig. 1 and perpendicular to the image plane of the Fig. 1 This allows the tool holder 14 and thus the comminution tool 12 to be moved in two dimensions. This makes it possible to precisely adjust the positions of the holes to be created within the range of motion covered by the arm 16.

[0044] In the schematic representation according to Fig. 1 It can be seen that the machine tool 10 has a liquid reservoir 18 In the fluid reservoir 18, cutting fluid 20 be stored. Via hoses 22 The liquid reservoir 18 can be flexibly connected to an inlet 24 and an outlet 26be connected. Cutting fluid 20 can thus be supplied to the comminution tool 12 via the inlet 24. Excess and / or used cutting fluid 20 can be returned to the machine tool 10 via the outlet 26. Furthermore, the machine tool 10 has an accumulator 28 which has a connection 30 the shredding tool 12 is supplied with electrical energy.

[0045] In the representation according to Fig. 1 is rock 32 to recognize, for example, concrete, which is to be processed with the crushing tool 12. In particular, a blind hole is to be drilled into the rock 32.

[0046] Fig. 2 shows a schematic representation of the structure of the crushing tool 12, which is placed on the rock 32 and processes it.

[0047] The shredding tool 12 has a housing 34The housing 34 contains a fluid management system 35 for the management of the cutting fluid 20, in particular for the storage, cleaning, conditioning and circulation of the cutting fluid 20.

[0048] Cutting fluid 20 comprises two fluid components, excluding any impurities. Water predominates, for example, in the range of 60 to 90%. The remaining portion is made up of a hydrophobic fluid component. The hydrophobic fluid component contains a highly volatile material. In particular, its vapor pressure is lower than that of water under standard conditions. In an alternative embodiment, cutting fluid 20, again excluding any impurities, consists of water.

[0049] With the help of valves 36, 38Cutting fluid 20 can be admitted into the fluid management system 35 via the inlet 24 or discharged from it via the outlet 26.

[0050] A pump 40 of the fluid management system 35 pumps cutting fluid 20 through a filter 42 of the fluid management system 35 to a conditioner 44.

[0051] By two actuators 46 pressure waves can 48 are generated. In Fig. 2 the pressure waves are symbolized by wavy lines.

[0052] The actuators 46 can, for example, comprise piezoelectric elements for generating the pressure waves 48. Each of the actuators 46 generates a maximum continuous power of at least 0.5 kW.

[0053] The pressure waves 48 run to a focuser 50. The focuser 50 collects the individual pressure waves 48 and generates a total pressure wave 52. In Fig. 2The total pressure wave 52 is also symbolized by wavy lines. The total pressure wave 52 runs on a focus area 54 where the total pressure wave 52 reaches its maximum amplitude by focusing.

[0054] The distance d of the focuser 50 from the rock 32 along the direction in which the total pressure wave 52 propagates is controlled by adjusting elements 55 adjustable. This also allows the position of the focus area 54 relative to the rock 52 to be adjusted. In order to be able to regulate the distance d according to the drilling progress, a distance meter 56 attached to the focuser 50. A control 58The comminution tool 12 is configured to automatically and continuously regulate the distance d during a drilling process to a specific target distance. The controller 58 can be configured as a microcontroller on which a correspondingly configured program code is executed. In alternative embodiments, the controller 58 is fully or partially integrated in the machine tool 10 (see Fig. 1 ) and not or at least not completely implemented in the crushing tool 12.

[0055] The conditioner 44 is configured to condition the cutting fluid 20, for example to adjust its flow velocity appropriately so that cavitations 60, in Fig. 2 symbolized by circles, in conjunction with the total pressure wave 52. The rock 32 is processed by imploding cavitations 60. In the illustration according to Fig. 2 is accordingly a blind hole 62formed by the crushing tool 12.

[0056] After passing or passing through the blind hole 62, the cutting fluid 20, which is now generally contaminated with particles mined from the rock 32, returns to the pump 40 and the filter 42, unless it flows through the valve 38, if this is open, and the outlet 26 back to the machine tool 10.

[0057] The filter 42 is arranged on an edge of the housing 34 and can be removed or inserted through a lateral resealable opening, for example for cleaning.

[0058] To prevent cutting fluid 20 from escaping, the housing 34 has a seal on the side with which the housing 34 is applied to the rock 32 64 The seal 64 can be, for example, a rubber ring seal. In particular, it has a working opening 66in the area of ​​the focus area 54. In an alternative embodiment, the housing 34 can also have a circumferential skirt for sealing. List of reference symbols

[0059] 10Machine tool 12Crushing tool 14Tool holder 16Arm 17Arrow 18Fluid reservoir 20Cutting fluid 22Hoses 24Inlet 26Outlet 28Accumulator 30Connection 32Rock 34Housing 35Fluid management system 36Valve 38Valve 40Pump 42Filter 44Conditioner 46Actuator 48Pressure wave 50Focuser 52Total pressure wave 54Focus area 55Adjusting element 56Distance meter 58Control system 60Cavitation 62Blind hole 64Seal 66Working opening dDistance

Claims

1. Shredding tool (12) for crushing rock (32) by pressure waves (48, 52) in a cutting fluid (20), wherein the crushing tool (12) has a housing (34) with a working opening (66), wherein cutting fluid (20) is located in the housing (34) and / or wherein the crushing tool (12) has an inlet (24) for cutting fluid (20), wherein the crushing tool (12) has an actuator (46) for generating a pressure wave (48, 52) in the cutting fluid (20).

2. Crushing tool (12) according to one of the preceding claims, characterized in that the actuator (46) has a continuous mechanical power of at least 0.5 kW, in particular of at least 1 kW.

3. Crushing tool (12) according to one of the preceding claims, characterized in that the comminution tool (12) has a focuser (50) for focusing the pressure wave (48) on a focus area (54).

4. Crushing tool (12) according to one of the preceding claims, characterized in that the shredding tool (12) is designed to automatically regulate a shredding performance.

5. Crushing tool (12) according to one of the preceding claims, characterized in that the comminution tool (12) comprises a fluid management system (35) having at least one pump (40) for conveying the cutting fluid (20).

6. Crushing tool (12) according to one of the preceding claims, characterized in that the fluid management system (35) has a filter (42) for cleaning the cutting fluid (20).

7. Crushing tool (12) according to one of the preceding claims, characterized in that a seal (64) is formed and / or arranged on an edge of a working opening (66) of the housing (34).

8. machine tool (10),comprising - a tool holder (14) which is designed to receive a comminution tool (12) according to one of the preceding claims.

9. Machine tool (10) according to one of the two preceding claims, characterized in that the tool holder (14) is located on an arm (16) which is adjustable in at least one dimension.

10. Cutting fluid (20) for a comminution tool (12) according to one of claims 1 to 7, in particular designed for comminution of rock (32) by means of cavitation (60), wherein the cutting fluid (20) has a fluid component which, under standard conditions, has a lower vapor pressure than water and / or which, at an ambient pressure of 101,325 Pa, has a lower evaporation temperature than water.

11. Cutting fluid (20) according to the preceding claim, characterized in thatthe liquid component is hydrophobic and the cutting fluid (20) comprises water as another component.

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