Device and method for applying cooling lubricants and grinding machine

Abstract

A device (50) serves to dispense cooling lubricants. The device (50) has a supply line (70) for the cooling lubricant supply, at least one nozzle (56, 156), and a vent valve (110, 210, 310). The at least one nozzle (56, 156) serves as the outlet nozzle for the cooling lubricants. The supply line (70) can be fluidically connected to the at least one nozzle (56, 156) by forming a fluid path (108) for the cooling lubricants. The vent valve (110, 210, 310) is associated with the fluid path (108). From the perspective of the at least one nozzle (56, 156), the vent valve (110, 210, 310) connects to the fluid path (108) upstream. The ventilation valve (110, 210, 310) can be automatically switched between a closed position and an open position.In the open position, the vent valve (110, 210, 310) provides an opening (120, 220, 320) between the fluid path (108) and the working chamber (16) to vent the fluid path (108) for faster coolant drainage. A grinding machine (10) is equipped with such a device (50).

Description

Technical field

[0001] The present disclosure relates to a device for dispensing cooling lubricants (CLs) in a working chamber of a grinding machine. The disclosure further relates to a grinding machine equipped with such a device. The present disclosure also relates to a relevant method for dispensing cooling lubricants. State of the art

[0002] Machine tools in the form of grinding machines are known in the prior art. The present disclosure relates in particular to the coolant supply (coolant supply) of grinding machines with rotaryally driven grinding wheels for machining workpieces. Grinding machines are designed as cylindrical grinding machines by way of example, but with appropriately designed kinematics, they can also be suitable for so-called non-circular grinding and for other grinding operations.

[0003] Grinding machines typically comprise a machine bed (or frame) and a work area enclosed by a housing. A workpiece spindle head for holding a workpiece and a grinding spindle head for holding a grinding wheel are usually mounted on the machine bed. The machine kinematics allow for infeed and feed movements between the grinding wheel and the workpiece. The workpiece can be machined by the rotating grinding wheel.

[0004] Cooling lubricants (also known as cutting fluids or cutting agents) are of paramount importance in grinding processes for achieving the desired performance, maximizing tool life, and meeting the required quality standards. Cooling lubricants serve to dissipate heat and reduce friction between the tool and workpiece. Furthermore, they are used for chip removal and the removal of tool wear debris.

[0005] For the application of cooling lubricants to the desired location and with the desired direction and / or spray pattern, there are established solutions, such as the so-called Loc-Line system from Lockwood Products, Inc., USA. This system comprises flexible arms with integrated fluid channels that are three-dimensionally deformable and can be fitted with nozzles.

[0006] WO 2019 / 115641 A1 discloses another approach to the application of cooling lubricants in grinding machines, comprising a modular nozzle arrangement with a distributor block providing multiple outlets, each serving as a seat for a cooling lubricant nozzle. Both the distributor block and the cooling lubricant nozzles can be additively manufactured. This allows the nozzle arrangement to be specifically adapted to a particular machining task.

[0007] From JP 2023-57601 A, a machine tool is known that is capable of detecting contact between the tool and the workpiece. For this purpose, the tool – which rotates independently of the spindle drive – is slowly brought close to the workpiece until the rotation stops due to contact.

[0008] JP 2023-57601 A proposes to generate tool rotation via a tangential flow, with a gaseous fluid exiting through a nozzle directed at the tool's circumference. The nozzle can optionally dispense a liquid coolant / lubricant for cooling, lubrication, and chip removal during machining. Alternatively, the same nozzle can be used to discharge air or another gas to gently drive the tool for contact detection. A directional control valve connects the nozzle to either a liquid or a gas source.

[0009] In operation, cooling lubricants represent a significant cost factor. Furthermore, cooling lubricants can cause considerable environmental pollution. Against this backdrop, cooling lubricant management is of considerable importance for grinding machines. When supplying a grinding machine with cooling lubricants, the goal is typically to achieve the desired performance values ​​and machining results with minimal stress on the workpiece, tool, and grinding machine, and with the lowest possible amount of cooling lubricant used.

[0010] The supply of cooling lubricants (also called coolant) should be adapted to the requirements of the machining cycle. In other words, the cooling lubricant should always be available when material removal is actually taking place, and its supply should be interrupted as much as possible when no material removal is occurring. For example, the supply of the cooling lubricant can be linked to the rotation of the grinding wheel, i.e., to the activation or deactivation of the grinding spindle. This is often achieved by controlling a valve (a so-called cycle valve) for the cooling lubricant supply depending on the operating state of the grinding spindle. Thus, when the grinding spindle is deactivated to slow down and stop the rotating grinding wheel, the cycle valve is also closed. Conversely, the cycle valve can be opened when the grinding spindle is activated to drive the grinding wheel rotationally.

[0011] It has been observed that the coolant supply sometimes reacts rather sluggishly. A considerable amount can still escape from at least one coolant supply nozzle even after the grinding spindle has been deactivated. However, if the coolant flows or drips onto the braked grinding wheel, it can lead to undesirable accumulations. This can even cause an unwanted imbalance in the grinding wheel, which in turn has adverse effects on the process.

[0012] Unwanted wetting of the grinding wheel can be prevented by moving at least one nozzle away from the grinding wheel, so that the dripping coolant does not reach it. However, this requires additional movements within the work area. Furthermore, challenges arise regarding the repeatability of the nozzle positions, which is essential for efficient coolant management.

[0013] Furthermore, it has been shown that the provision of the coolant (coolant flows out of at least one nozzle in the desired quantity) also takes time when restarting the grinding spindle, which may extend the cycle time. Disclosure of the invention: Problem, solution, advantages

[0014] Against this background, the present disclosure aims to provide a device for dispensing cooling lubricants and a grinding machine equipped with such a device, with which cooling lubricant management can be further optimized. In particular, the aim is to minimize or completely prevent detrimental dripping or flow of the cooling lubricant after the grinding spindle is switched off. Furthermore, the cooling lubricant should be available as quickly as possible after the grinding spindle is switched on, so that machining can begin promptly. In general, cycle times should be optimized as much as possible. Additionally, damage to the stationary (braked) grinding wheel from dripping cooling lubricant should be prevented as far as possible.

[0015] This problem is solved by a device having the features specified in claim 1, and by a grinding machine having the features specified in claim 14. Advantageous embodiments and expedient further developments of the present invention are characterized in the respective dependent claims.

[0016] According to a first aspect, the present disclosure relates to a device for dispensing cooling lubricants, in particular in a working space of a grinding machine having at least one grinding spindle for receiving a grinding wheel, wherein the device comprises the following: a supply line for the coolant supply, at least one nozzle serving as an outlet nozzle for coolants, wherein the supply line is fluidically connectable to the at least one nozzle by forming a fluid path for the coolants, and a venting valve associated with the fluid path and coupled upstream of the fluid path from the perspective of the at least one nozzle, wherein the venting valve is automatically switchable between a closed position and an open position and, in the open position, releases an opening between the fluid path and the working chamber to vent the fluid path for faster coolant drainage, and wherein the venting valve is a pressure-controlled valve that is switchable between the closed position and the open position depending on a pressure in the supply line.

[0017] The task of disclosure is thus accomplished. Furthermore, the task of disclosure is accomplished through a corresponding procedure. Unless otherwise stated or evident from the context, the following embodiments and developments apply equally to the device and the procedure. Features explained in connection with the device are analogous to those of the procedure, and vice versa.

[0018] As disclosed, the emptying of the fluid path in the vicinity of the nozzle can be accelerated by targeted venting. If the coolant supply is to be interrupted by closing a valve (cycle valve, i.e., not the vent valve) that blocks the fluid path, or by deactivating a coolant pump, a negative pressure can be created, similar to that in a water hose still connected to a fitting, which at least delays the flow of the coolant. Targeted venting of the fluid path via the additional vent valve ensures that ambient air can flow into the fluid path more easily and quickly. The coolant can then flow out more rapidly.

[0019] If the fluid path is quickly emptied, at least in the vicinity of the nozzle(s), dripping is effectively reduced or even prevented. This can have a positive impact on cycle times. Furthermore, at least one nozzle can remain in its operating position; the nozzle does not need to be moved away from the grinding wheel. Overall, this can result in a more stable process, and any adverse effects on machining accuracy can be significantly reduced or completely eliminated.

[0020] A device as disclosed may also be referred to as a coolant supply device. Insofar as this disclosure refers to the need to empty the fluid path, this primarily relates to unwanted dripping. Partial quantities of the coolant that remain within the fluid path without dripping or delayed discharge are not considered problematic.

[0021] In the open position, the vent valve allows air exchange between the fluid path and the environment. In the closed position, the vent valve is blocked. The coolant is not intended to pass through the vent valve. Likewise, air is not intended to be released from the fluid path to the environment through the vent valve. The primary purpose of the vent valve is to allow air to flow into the fluid path when the vent valve is open. From the perspective of the vent valve, the environment is typically the atmosphere within the working area of ​​the grinding machine, i.e., the space within the grinding machine's enclosure.

[0022] The vent valve can be operated automatically. Ideally, the vent valve is operated automatically depending on process-related parameters. For example, the vent valve can be automatically (and if necessary, independently) switched between the open and closed states depending on the pressure in the fluid path or on a differential pressure between the fluid path and the environment (e.g., in the working area of ​​the grinding machine).

[0023] The opening of the vent valve can also be referred to as a ventilation port. The ventilation port is fluidically connected to the atmosphere in the grinding machine's working chamber. From there, air can flow into the fluid path via the ventilation port when the vent valve is in the open position. In the open position, the vent valve provides a fluidic connection (for incoming air) between the machine tool's working chamber and the fluid path. This is in addition to the opening provided by the at least one nozzle.

[0024] At least one vent valve connects to the fluid path upstream of at least one nozzle. If the fluid path is vented at this point, any coolant that might be trapped in the fluid path between the vent valve and the nozzle can drain away quickly. This is advantageous, for example, if the trapped coolant would otherwise create a vacuum in the fluid path. This vacuum can be quickly relieved by the inflow of air when the vent valve is open.

[0025] Where this disclosure refers to a proximity between the vent valve and the at least one nozzle, this also includes configurations in which the vent valve is located at least somewhat upstream of the at least one nozzle. Where this disclosure refers to cooling lubricant(s), this primarily refers to a liquid that flows along the fluid path. The fluid that can flow into the fluid path via the vent valve in the open position is primarily a gas, usually air. It is not excluded that the gas contains process gases; the gas composition typically corresponds to that of the atmosphere in the working space.

[0026] From the perspective of the fluid path and coolant transport, the vent valve does not function as a pressure relief valve. Its purpose is not to open in the event of excessively high pressure along the fluid path. Instead, it regularly serves to allow a gas (usually air) to flow in, thus preventing a vacuum from forming in the fluid path.

[0027] The opening and closing pressure (generally: switching pressure) of the vent valve can be determined, for example, by the geometry, arrangement, and mass of the movable valve element. Fine-tuning of the pressure can be achieved, for example, by varying the weight of the valve element. It is also conceivable to couple the valve element with at least one spring. The spring can force the valve element either towards the closed position or towards the open position. In this way, the (automatic, self-acting) actuation of the vent valve can be specifically adapted to the pressure conditions along the fluid path under different operating conditions.

[0028] According to an exemplary embodiment, the ventilation valve has a movable valve element and a valve seat, wherein the movable valve element is in a sealing position against the valve seat in the closed position and is moved away from the valve seat in the open position.

[0029] The valve element is exemplified as a sphere, cone, or pin with a straight or at least partially conical end face. The valve seat typically includes a bore against the edge of which the valve element can seal. In exemplary embodiments, the valve element is arranged between the valve seat and the fluid path; from the perspective of the valve element, the valve seat is thus located on the side of the vent valve where the opening to the environment (the working chamber) is also situated.

[0030] According to a further exemplary embodiment, the device further comprises a connection block, wherein the supply line couples to the connection block on the inlet side, wherein the at least one nozzle couples to the connection block on the outlet side, wherein the fluid path between an inlet and at least one outlet extends through the connection block, and wherein the vent valve is arranged at the connection block.

[0031] In other words, the terminal block has an internal flow-guiding contour. The vent valve can be flanged to or integrated into the terminal block. The terminal block can be a single piece or multi-piece. This includes, for example, a housing with a two-piece (or multi-piece) design, the upper part of which contains the inlet and the lower part of which is designed to carry multiple nozzles for dispensing the coolant.

[0032] The connection block, for example, is the part of the device that can be moved via a tracking drive. This allows the position of at least one nozzle to be adjusted to the wear of the grinding wheel.

[0033] According to another exemplary embodiment, several nozzles are connected to the connection block, with the fluid path within the connection block having a branch. In this way, the connection block can accommodate one or more nozzles, which may be identical or different in design. Thus, the connection blocks can be specifically configured for a particular application. If a connection block provides multiple seats for accommodating several nozzles, some of these seats can be closed off with blanking plugs if fewer nozzles are required than there are seats.

[0034] The connection block can also be used to integrate or accommodate additional components, including, besides the vent valve, a coolant sensor, which could be, for example, a pressure sensor and / or flow sensor. The coolant sensor can be designed, for example, as a dynamic pressure sensor, flow sensor, etc.

[0035] According to another exemplary embodiment, the vent valve connects to the fluid path on the inlet side, upstream of the branch. In other words, a single vent valve can thus support the draining of an arrangement with multiple nozzles. This significantly simplifies the actuation and any control of the vent valve. The term "inlet side, upstream of the branch" refers to the flow direction of the cooling lubricant. In other words, according to this design, the vent valve connects to the fluid path upstream of the branch.

[0036] According to another exemplary embodiment, the vent valve is in the closed position when a pressurized cooling lubricant flows along the fluid path, and the vent valve is moved into the open position when the pressure in the fluid path drops and falls below a threshold value.

[0037] In this way, the actuation of the valve can be controlled by the coolant itself. When the coolant flows along the fluid path at sufficient pressure and exits through at least one nozzle, the pressure exceeds an opening pressure at which the vent valve would open. In other words, according to this design, the higher the pressure of the coolant flowing along the vent valve, the tighter / more tightly closed the vent valve is. If the supply of pressurized fluid is interrupted (for example, after the grinding spindle is switched off) by closing the cycle valve, the pressure in the fluid path drops noticeably. If the pressure in the fluid path falls below the opening pressure of the vent valve, the vent valve can open. Then, air from the outside (from the working chamber) can flow into the fluid path.

[0038] If the coolant itself (due to its pressure) actuates the vent valve, the result is a particularly simple and robust design. According to this design, the vent valve does not need to be controlled separately (via a separate actuator).

[0039] According to another exemplary embodiment, the vent valve includes an actuator that can be connected to a control unit via a control line. In this embodiment, the vent valve is not necessarily actuated directly by the pressure in the coolant. For example, a shutdown signal (grinding spindle is switched off) can be used for coolant management to stop the supply of coolant altogether (closing the cycle valve or stopping the coolant pump). This shutdown signal can also be used to actuate the vent valve. In other words, additional sensors and the like are not necessarily required to provide the necessary signals. Instead, signals that are already processed by the grinding machine's control unit can be used.

[0040] In other words, according to one exemplary embodiment, a control device is installed which is designed to open the vent valve in response to a shutdown signal, in particular a shutdown signal indicating an operating state of the grinding wheel. The control device can be a coolant control device. The control device can also be part of a higher-level machine control system.

[0041] According to another exemplary embodiment, the control unit is configured to actuate the actuator to open the vent valve when the coolant supply is interrupted and / or the grinding spindle is switched off. This ensures that the fluid path is emptied quickly and that, as far as possible, no coolant escapes with a delay (drip). The aim is to empty the fluid path within the time required for the grinding spindle to decelerate the grinding wheel to a standstill. When the grinding spindle is restarted, the control unit can actuate the actuator to close the vent valve.

[0042] According to another exemplary embodiment, the actuator is either a fluidic or an electromagnetic actuator. Other actuation principles are conceivable, such as piezoelectric actuators or the like. An electromagnetic actuator uses electrical energy. A fluidic actuator uses fluidic energy (pneumatics, hydraulics). The vent valve can be a direct-acting valve, in which the actuator acts directly on the valve element. The vent valve can also be a pilot-operated valve, in which the actuator acts on a pilot valve. The vent valve can have an automatic return mechanism, for example, by means of a spring return, which always forces the vent valve into the closed (or open) position.

[0043] According to another exemplary embodiment, the fluid path extends along a siphon. A siphon stores at least a portion of the cooling lubricant in the fluid path without any undesirable dripping or flowing of this portion. A siphon creates a geometric obstacle for the cooling lubricant flowing along the fluid path. As long as the cooling lubricant is sufficiently pressurized, it can easily pass through the siphon. However, if the pressure in the fluid path decreases, the cooling lubricant can no longer overcome the geometric obstacle.

[0044] A siphon ensures, on the one hand, that for the complete emptying of the fluid path (within the meaning of the present disclosure) to prevent overflow / drip, only a portion of the coolant present in the fluid path actually needs to flow out. Furthermore, a siphon ensures that the coolant can be made available quickly when the grinding spindle is reactivated. Because a portion of the coolant can remain in the fluid path, the fluid path can be filled more quickly, and the coolant can be made available more quickly via at least one nozzle.

[0045] A section of the fluid path is designed like a siphon. In one exemplary embodiment, the siphon is located adjacent to the at least one nozzle and adjacent to the vent valve in the fluid path. This also includes configurations with a distance between the siphon and the at least one nozzle. The distance between the siphon and the at least one nozzle is typically small compared to the total length of the supply line.

[0046] According to another exemplary embodiment, the vent valve is connected to the fluid path downstream of the siphon. In this way, the vent valve can be used to accelerate the emptying of the fluid path between the siphon and the nozzle. From the siphon's perspective, the vent valve is connected to the fluid path downstream.

[0047] According to another exemplary embodiment, the siphon is a tubular siphon, which is formed particularly in the connection block. The term tubular siphon does not necessarily encompass the design of the siphon from pipe sections. Instead, the term tubular siphon refers to the design of the fluid channel along the fluid path that forms the siphon. In other words, U-shaped or J-shaped channel sections can be combined to form the tubular siphon.

[0048] When installed, at least an upstream section of the siphon lies below the downstream end. A siphon is formed, for example, by an S-shaped channel formed by U-shaped or J-shaped channel sections. It goes without saying that the siphon's function requires correct installation orientation, in which gravity ensures that coolant collects in the siphon and remains there even when the downstream section of the fluid path (from the siphon's perspective) is emptied.

[0049] For example, if the connection block is additively manufactured, curved channels can be easily formed within it. This allows for relatively simple manufacturing of the siphon. Furthermore, the connection block can still be designed to be compact and sufficiently robust.

[0050] According to a further exemplary embodiment, the device also includes a coolant pump and at least one coolant sensor, which can be coupled to a control unit that evaluates signals from the coolant sensor and operates the coolant pump on this basis in order to deliver a desired quantity of fluid.

[0051] An alternative embodiment involves controlling the system via a regulating valve. This also allows for fine-tuning of the coolant supply based on the sensor signal. According to this embodiment, it is possible to use a pump that operates at a constant or essentially constant speed.

[0052] The device also features, for example, a cycle valve that connects to the supply line between the coolant pump and the connection block. The cycle valve shuts off the supply line when the coolant supply is to be interrupted.

[0053] According to another aspect, the present disclosure relates to a grinding machine with a workpiece holder for receiving a workpiece and at least one grinding spindle for receiving a grinding wheel, wherein the workpiece holder and the grinding spindle are movable relative to each other in a working space in order to machine a workpiece which is held on the workpiece holder, and with a device for dispensing cooling lubricants according to at least one of the embodiments described herein.

[0054] The coolant supply control unit can be part of a (global) control unit for the grinding machine. Alternatively, a separate control circuit can be provided for the coolant supply. A pump characteristic curve, or operating parameters and pump characteristics, are stored in the control unit's memory. The pump can be, for example, a frequency-controlled pump. The grinding machine can have a coolant circuit that also includes collection and recovery of the coolant. It is understood that such coolant supply systems can also be designed as a larger, centralized system and, for example, cover multiple grinding machines.

[0055] According to another exemplary embodiment of the grinding machine, the nozzle assembly is mounted on a grinding spindle stock so that it can be moved relative to the grinding spindle. For this purpose, a drive can be provided that can move the nozzle assembly, in particular the connecting block with the nozzles mounted on it, in order to follow the tool wear, especially the grinding wheel wear. The drive can also be referred to as a tracking drive. In this way, it is ensured that an optimal coolant supply is guaranteed even when the tool is wearing down.

[0056] The present invention further relates to a method for applying cooling lubricants, in particular in a working chamber of a grinding machine having at least one grinding spindle for receiving a grinding wheel, comprising the following steps: Provision of a supply line for the coolant supply, provision of at least one nozzle that serves as an outlet nozzle for coolants, connection of the supply line to the at least one nozzle to form a fluid path for the coolants, provision of a vent valve that is assigned to the fluid path and is coupled to the fluid path upstream from the perspective of the at least one nozzle, and automated switching of the vent valve between a closed position and an open position. wherein the vent valve in the open position releases an opening between the fluid path and the working space in order to vent the fluid path for faster coolant drainage, and wherein the vent valve is a pressure-controlled valve which can be switched between the closed position and the open position depending on a pressure in the supply line (70).

[0057] Finally, the present invention relates to the use of a device of the type described above and / or a method of the type described above in a grinding machine for applying cooling lubricants.

[0058] It is understood that the features mentioned above and those to be explained below can be used not only in the combinations specified, but also in other combinations or on their own, without leaving the scope of this disclosure. Brief description of the drawings

[0059] Further features and advantages of the invention will become apparent from the following description and explanation of several exemplary embodiments with reference to the drawings. These show: Fig. 1: a perspective view of a grinding machine; Fig. 2: a schematic block view of components of a device for dispensing cooling lubricants for the coolant supply (coolant supply) of a grinding machine; Fig. 3: a partial perspective view of a grinding spindle with a connection block for the coolant supply, which is associated with a grinding wheel; Fig. 4: a schematic block view of components of a device according to the disclosure for further detailing of the connection block; Fig. 5: a perspective sectional view through a section of a connection block of a device according to the disclosure; Fig. 6: another perspective sectional view through a section of a connection block of a device according to the disclosure with a opposite Fig. 5offset section plane; Fig. 7: a perspective view of a further embodiment of a connection block of a device according to the disclosure; Fig. 8: a sectioned partial view of the connection block according to Fig. 7 ; and Fig. 9: a on Fig. 4 Block view based on the diagram to illustrate a further embodiment of a device as disclosed. embodiment(s) of the invention

[0060] Fig. 1 Figure 10 illustrates an exemplary design of a grinding machine, designated as such, using a perspective view. In this embodiment, the grinding machine 10 is designed as a cylindrical grinding machine.

[0061] The grinding machine 10 comprises a machine bed 12, which can also be referred to as a frame. The machine bed 12 supports various components of the grinding machine 10. These include, among other things, an enclosure 14 that surrounds a working chamber 16. A grinding spindle stock 20 is arranged in the working chamber 16, which has at least one grinding spindle 22 designed to hold and drive a grinding wheel 24. The grinding spindle 22 includes a rotary drive for rotating the grinding wheel 24. In the exemplary embodiment, the grinding wheel 24 is at least partially covered by a protective hood 26.

[0062] A workpiece spindle stock 30 is also arranged in the work area 16, which has a workpiece holder 32 for receiving a workpiece 34. The workpiece spindle stock 30 typically has a workpiece spindle with a rotary drive for rotating the workpiece 34. The grinding machine 10 also has kinematics that enable the necessary infeed and feed movements between the grinding wheel 24 and the workpiece 34 within the work area 16.

[0063] In Fig. 1Furthermore, a control unit for the grinding machine 10 is indicated by 40. The control unit 40 serves to control the drives of the grinding spindle stock 20 and the workpiece spindle stock 30, as well as to control the traverse drive for providing traverse movements between the grinding spindle stock 20 and the workpiece spindle stock 30. In addition to these main functions, the control unit 40 also serves to control various secondary functions of the grinding machine 10. This can also include the so-called coolant management (CMS management). The control unit 40 can be designed as a distributed control unit. The control unit 40 does not necessarily have to be structurally integrated into the grinding machine 10. The grinding machine 10 can also be controlled in at least one operating mode via external control units that are accordingly coupled to the grinding machine 10.

[0064] The grinding machine 10 also has an operator interface 42, which is located outside the working area 16. Consequently, an operator can control, program, regulate, and / or, for example, perform diagnostics on the grinding machine 10 without coming into contact with the interior of the working area 16 of the grinding machine 10. The operator interface 42 includes elements for inputting control commands and elements for outputting information.

[0065] Fig. 2Figure 50, a schematic block diagram, shows a device for dispensing cooling lubricants (CL). Cooling lubricants can also be generally referred to as coolants. The device 50 can also be called a CL supply device. The device 50 has a nozzle arrangement 52, which includes a connection block 54 serving as a distributor block and at least one nozzle 56. The nozzle 56 is directed with its outlet opening towards a space between the grinding wheel 24 and the workpiece 34. Cooling lubricants are introduced by the device 50 through the nozzle 56 into this area where machining takes place. In this way, excess heat can be dissipated. Furthermore, chips or tool wear can be removed. In addition, the supply of cooling lubricants can serve to create favorable friction conditions between the grinding wheel 24 and the workpiece 34.

[0066] The nozzle assembly 52 also includes a coolant sensor 58, which is flanged to the distributor block 54. The sensor 58 can be, for example, a pressure sensor, such as a dynamic pressure sensor. Generally, the sensor 58 can also be designed as a flow sensor. The sensor 58 is mounted on a sensor receptacle of the distributor block 54.

[0067] Sensor 58 is connected to a coolant control unit 64 via a control line 62. The coolant control unit 64 can be integrated as part of the (higher-level) control unit 40 of the grinding machine 10 or implemented as a separate unit. In the exemplary embodiment, the coolant control unit is connected to a pump 68 for pressure generation via a control line 66. Preferably, the pump 68 is a variable-speed pump. Thus, the coolant control unit 64 can control the pump 68 depending on the signal transmitted by sensor 58. The pump 68 is connected to an input on the distributor block 54 via a line 70. Furthermore, the pump 68 is connected to a reservoir 72 via a line designated 74.

[0068] Line 70 can also be referred to as the supply line. A valve 76, which can also be referred to as a cycle valve, is arranged in line 70. In exemplary embodiments, the cycle valve 76 serves to block or release the flow of coolant along the supply line 70.

[0069] It is understood that the device 50 may also include measures for collecting and cleaning / recycling cooling lubricants. Accordingly, a cooling lubricant circuit may also be provided.

[0070] The nozzle assembly 52 is mounted on a carrier 80 of a nozzle feed unit 82. The nozzle feed unit 82 allows the nozzle assembly 52 to be adjusted to the respective wear condition or to reduce the diameter of the grinding wheel 24. A double arrow labeled 84 illustrates a direction of movement of the nozzle assembly 52. ​​The nozzle feed unit 82 is attached, for example, to the grinding spindle stock 20 or to the protective hood 26.

[0071] Generally, it is desirable for the required quantity of coolant to be available during machining to achieve the desired results. Conversely, however, an excess of coolant consumed should be avoided as much as possible. When the grinding wheel 24 starts up, the coolant should exit the at least one nozzle 56 as quickly as possible so that machining of the workpiece 34 can begin promptly. When the grinding wheel 24 stops, the coolant flow should cease as quickly as possible. This serves both to reduce consumption and to prevent adverse effects, such as the stationary grinding wheel 24 being wetted by dripping coolant.

[0072] Fig. 3 Figure 2 illustrates a partial view of a grinding spindle 22 with a grinding wheel 24 using a perspective drawing. The grinding spindle 22 is an example of the one described in Figure 2. Fig. 1taken from the grinding machine 10 shown schematically. A nozzle arrangement 52 is assigned to the grinding wheel 24, which is part of a device 50 according to the disclosure (compare Fig. 2 ) may be.

[0073] The nozzle assembly 52 comprises a connection block 54, which in the exemplary embodiment is equipped with two nozzles 56 and a coolant sensor 58. In the exemplary embodiment, the connection block 54 has a housing 86, which can be designed as a single piece or in multiple parts. The housing 86 is manufactured, for example, by additive manufacturing processes. The nozzles 56 can also be manufactured by additive manufacturing processes. In this context, reference is made to WO 2019 / 115641 A1, which discloses approaches for manufacturing the housing 86 and the nozzles 56.

[0074] In the exemplary embodiment according to Fig. 3The housing 86 of the terminal block 54 is a multi-part housing composed of two or more housing parts 88 and 90. Housing part 88 can also be referred to as the lower housing part. Housing part 90 can also be referred to as the upper housing part. This is not to be understood as a limitation.

[0075] The terminal block 54 has an inlet 92 for the coolant, which is formed, for example, in the upper housing part 90 of the housing 86. For example, the supply line 70 ( Fig. 2 The terminal block 54 is fluidically coupled to input 92. It also has a connection 94 for the coolant sensor 58. The terminal block 54 provides one or more outputs 96, each of which serves to receive a nozzle 56. In the exemplary embodiment, the outputs 96 are located on the lower housing part 88 of the housing 86. The terminal block 54 according to Fig. 3The terminal block 54 has four outputs 96, only two of which are fitted with nozzles 56. The other two outputs 96 are each closed by a blanking plug 102. Securing slides 104 serve to secure the nozzles 56 and the blanking plugs 102 to the housing 86. The terminal block 54 can be variably fitted with nozzles 56 (and blanking plugs 102), resulting in a wide variety of nozzle arrangements 52.

[0076] Fig. 4 Figure 1 shows a schematic block view of a device 50 according to the disclosure for dispensing cooling lubricants. The device 50 has a nozzle arrangement 52 with a connection block 54 and two nozzles 56 and is based in this respect on the one described in Figure 1. Fig. 3 shown design. In Fig. 4 Furthermore, the direction of gravity is indicated by an arrow labeled G. In this embodiment, this provides at least an approximate spatial orientation of the nozzle arrangement 52.

[0077] Terminal block 54 is in Fig. 4 The terminal block 54 is represented as a dashed block. For example, the terminal block 54 has a multi-part housing 86 with two housing parts 88, 90 that can be connected to each other. Likewise, the terminal block 54 can have an integrally designed (one-piece) housing 86. Similarly, the housing 86 of the terminal block 54 can consist of three or more parts.

[0078] Terminal block 54 incorporates a branch 106. A single inlet 92 for the coolant, to which the supply line 70 connects, branches into four paths at branch 106 to supply the four outlets 96. Branch 106 can be easily integrated into terminal block 54 if the housing 86 (one-piece or multi-piece) is manufactured using additive manufacturing.

[0079] A fluid path 108 extends through the connection block 54, the flow direction of which is determined by the in Fig. 4 The arrows shown illustrate this. The cooling lubricant flows through the terminal block 54 along the fluid path 108, which is formed by corresponding channels within the terminal block 54. The fluid path 108 branches out at the junction 106.

[0080] A vent valve 110 is connected to the fluid path 108. The vent valve 110 is, for example, flanged to the connection block 54 (to its housing 86) and fluidically connected to the fluid path 108 via a vent line 112. In the exemplary embodiment, the vent valve 110 has a seat 116 and a movable valve element 118, which serves as a closing element. The seat 116 provides a connection to an opening 120, which serves as an inlet. When the movable valve element 118 seals against the seat 116, the vent valve 110 is in the closed position. In the closed position, no air from the surroundings (for example, the atmosphere in the working chamber 16) can flow into the fluid path 108 via the opening 120 and the vent valve 110.

[0081] In the exemplary embodiment according to Fig. 4The vent valve 110 is in the closed position when a sufficiently high pressure prevails in the fluid path 108. This is usually the case when the coolant flows along the fluid path 108 at the required operating pressure during normal operation and exits the nozzles 56 to wet the grinding wheel 24 and the workpiece 34; see also Fig. 2 However, once machining is complete and the grinding spindle 22 is deactivated to stop the grinding wheel 24 (which is no longer engaged with the workpiece 34), no more coolant should escape from the nozzles 56 as soon as possible. The coolant supply is interrupted, for example by closing the cycle valve 76 or deactivating the coolant pump 68; see also Fig. 2 .

[0082] The interruption of the coolant supply causes a pressure drop in fluid path 108 because no pressurized coolant flows in. This causes the valve element 118 to move away from the seat 116. This opens the vent valve 110, allowing air to flow in through opening 120. The air counteracts any potential negative pressure in fluid path 108, particularly downstream of vent valve 110 towards the outlets 96. The incoming air ensures that any remaining coolant in fluid path 108 drains away quickly. Dripping is effectively minimized or prevented.

[0083] The vent valve 110 is pressure-controlled. The valve element 118 can be pressed against the seat 116 by the pressure in the fluid path 108, against gravity (arrow G), to close the vent valve 110. It is also conceivable to additionally apply a spring to the valve element 118. Depending on the desired opening characteristic and installation situation, the spring can push the valve element 118 onto or away from the seat 116.

[0084] Within the connection block 54, the fluid path 108 forms a siphon 130. In the exemplary embodiment according to Fig. 4 The siphon is designed as a tubular siphon 132. A tubular siphon 132 has an S-shaped channel structure. A tubular siphon 132 is formed, for example, by U-shaped or J-shaped channel sections.

[0085] The siphon 130 presents a geometric obstacle for the coolant flowing along the fluid path 108. In other words, the coolant must flow through a valley within the terminal block 54 and subsequently a mountain (compare the direction of gravity G in Fig. 4 ) before it can exit the connection block 54 via the nozzles 56. As long as the coolant is sufficiently pressurized, this obstacle can be easily overcome. However, if the coolant flow is interrupted, the pressure in the fluid path drops rapidly. The remaining coolant is trapped by the siphon 130.

[0086] From the perspective of the siphon 130, the downstream coolant can still flow away. The vent valve 110 can assist the coolant flow there. When machining with the grinding wheel 24 is to be resumed and the coolant is to be supplied again, the siphon 130 shortens the required start-up time because at least a portion of the coolant remains in the fluid path 108 and the supply line 70, so that only a smaller quantity of (new) coolant is required to completely fill the fluid path 108.

[0087] Both the provision of the ventilation valve 110 and the provision of the siphon 130 can help to reduce cycle times when machining workpieces 34 in the grinding machine 10.

[0088] The Figures 5 and 6Illustrate exemplary designs of connection blocks 54 using cutaway perspective views, in which a ventilation valve 110 ( Fig. 5 ) and / or a 130 mm siphon ( Fig. 6 ) are built-in or otherwise integrated. In the Figures 5 and 6 Each housing part 90 of the housing 86 of the terminal block 54 is shown in a cutaway view. The fluid path 108 extends through the housing part 90. The housing part 90 can be part of a one-piece or multi-piece housing 86. In this respect, the illustration is in accordance with the Figures 5 and 6 not to be understood as restrictive.

[0089] The vent valve 110 is connected to the fluid path 108 (channel through the housing 86) via the vent line 112. The vent valve 110 has a seat 116 and a movable valve element 118, which in this embodiment is designed as a valve pin and has a conical contact surface for bearing against the seat 116. The seat 116 has a mating surface facing the valve element 118. When the valve element 118 is lifted / moved away from the seat 116 (for example, due to its own weight), air can enter through the opening 120 and flow through the vent valve 110 towards the fluid path 108. When the pressure in the fluid path 108 is high enough, the valve element 118 is pressed against the seat 116, and the vent valve 110 is closed. No air can flow into the fluid path 108 via the vent valve 110. With the vent valve 110 open, the fluid path 108 can be emptied quickly and efficiently.

[0090] Fig. 6 differs from the representation in Fig. 5 primarily through a different cutting plane through the housing part 90. Fig. 6 shows the coolant sensor 58, which connects to terminal 94. The coolant sensor 58 is connected via the in Fig. 6 indicated control line 62 with the coolant control 64 or the control unit 40 of the grinding machine 10 ( Figures 1 and 2 ) connectable. The KSS sensor 58 can be used to detect the pressure or quantity of the cooling lubricant flowing through the fluid path 108.

[0091] The fluid path 108 extends between the inlet 92 (for the supply line 70) and the outlets 96 of the terminal block 54 ( Fig. 4 The fluid path 108 extends through a siphon 130, which is shown in the sectional view according to Fig. 6The siphon 130 is designed in the form of a horizontal S, similar to a tubular siphon 132. The siphon 130 can retain at least a portion of the coolant when the pressure in the fluid path 108 decreases. This has a beneficial effect on emptying the fluid path 108 to reduce dripping and on refilling the fluid path 108 to replenish the coolant when machining resumes.

[0092] In Fig. 6 The opening of the ventilation line 112 of the ventilation valve 110 into the fluid path 108 is also shown. From the perspective of the siphon 130, the ventilation valve 110 connects to the fluid path 108 downstream. From the perspective of the ventilation valve 110, the siphon 130 is formed upstream in the fluid path 108.

[0093] With reference to the Figures 7 and 8Another embodiment of a device 150 according to the disclosure is illustrated. To avoid repetition, the following discussion focuses primarily on elements of device 150 that differ in design from device 50.

[0094] The device 150 comprises a nozzle assembly 152 based on the so-called Loc-Line system (Lockwood Products, Inc., USA). A terminal block 154 with a housing 186 has a plurality of outlets 196, each serving to receive a nozzle 156 via an articulated hose 160. The outlets 196 can be individually blocked or enabled. The housing 186 is attached to a support 180, the function of which corresponds to that of the support 80 according to Fig. 2 The connection block 154 has an inlet 192 for coolant, which can exit the nozzle assembly 152 via the nozzles 156.

[0095] Fig. 8Figure 1 shows a perspective view of a section through the housing 186 of the terminal block 154. A vent valve 210 is arranged at the terminal block 154, which is connected to the fluid path (in) via a vent line 212. Fig. 8 (not specifically named) couples. The vent valve 210 comprises a seat 216 and a valve element 218. When the valve element 218 is moved away from the seat 216, air from the working chamber can flow through the vent valve 210 via the opening 220 into the fluid path to accelerate the emptying of the nozzle assembly 152 or the connection block 154. The connection block 154 with the housing 186 can also accommodate a siphon, but this is not shown in the Figures 7 and 8 not explicitly shown.

[0096] Fig. 9 is based on the schematic block representation according to Fig. 4and shows a device 50 with a largely identical design. To avoid repetition, the following discussion will focus primarily on distinguishing features. In the exemplary embodiment, the device 50 has a ventilation valve 310, which is designed as an externally actuated valve.

[0097] The ventilation valve 110 according to Fig. 4 is controlled by the pressure of the flowing coolant. The vent valve 310 according to Fig. 9 In the exemplary embodiment, the valve is designed as a 2 / 2-way valve with a flow-through position and a blocking position. An actuator 322, for example an electromagnet, serves to actuate the vent valve 310. Furthermore, a spring return is provided in the exemplary embodiment. In the open position of the vent valve 310 (in Fig. 9(where the closed position is shown) air can pass through the opening 320, the ventilation valve 310 and flow into the fluid path 108 via the ventilation opening 312.

[0098] Actuator 322 is controlled via a control line 324. Control line 324 can be connected, for example, to the coolant control unit 64 or the (higher-level) control device 40; see also [reference to be added]. Fig. 2 Instead of an electromagnetic actuator 322, a fluidically actuated actuator can also be installed. Piezo actuators and other designs are also conceivable. The ventilation valve 310 can also be controlled via a pilot valve, which in turn is controlled by an actuator or by the flowing coolant.

[0099] The in Fig. 9The configuration shown requires an external impulse, i.e., a signal via control line 324, to actuate the vent valve 310. However, a signal to stop the coolant supply is usually already present, for example, a shutdown signal that switches off the grinding spindle 22 and slows down the grinding wheel 24. This signal can be used to interrupt the supply of coolant via supply line 70 (see figure). Fig. 2 ) and can also be used to open the ventilation valve 310.

Claims

1. Device (50) for dispensing cooling lubricants, in particular in a working chamber (16) of a grinding machine (10) having at least one grinding spindle (22) for receiving a grinding wheel (24), wherein the device (50) comprises: - a supply line (70) for supplying the cooling lubricant, - at least one nozzle (56, 156) which serves as an outlet nozzle for cooling lubricants, wherein the supply line (70) can be fluidically connected to the at least one nozzle (56, 156) by forming a fluid path (108) for the cooling lubricants, and - a vent valve (110, 210, 310) which is associated with the fluid path (108) and is coupled to the fluid path (108) upstream from the perspective of the at least one nozzle (56, 156), wherein the vent valve (110, 210, 310) automatically switches between a closed position and an open position. The position is switchable and in the open position there is an opening (120, 220,320) between the fluid path (108) and the working space (16) to vent the fluid path (108) for faster coolant drainage, , characterized by the fact that The ventilation valve (110, 210, 310) is a pressure-controlled valve that can be switched between the closed position and the open position depending on the pressure in the supply line (70).

2. Device (50) according to claim 1, wherein the ventilation valve (110, 210, 310) has a movable valve element (118, 218) and a valve seat (116, 216), and wherein the movable valve element (118, 218) is in a sealing position against the valve seat (116, 216) in the closed position and is moved away from the valve seat (116, 216) in the open position.

3. Device (50) according to claim 1 or 2, further comprising a connection block (54, 154), wherein the supply line (70) is coupled to the connection block (54, 154) on the inlet side, wherein the at least one nozzle (56, 156) is coupled to the connection block (54, 154) on the outlet side, wherein the fluid path (108) extends through the connection block (54, 154) between an inlet (92) and at least one outlet (96), and wherein the vent valve (110, 210, 310) is arranged at the connection block (54, 154).

4. Device (50) according to claim 3, wherein several nozzles (56, 156) couple to the connection block (54, 154), and wherein the fluid path (108) within the connection block (54, 154) has a branch (106).

5. Device (50) according to claim 4, wherein the ventilation valve (110, 210, 310) couples to the fluid path (108) on the inlet side before the branch (106).

6. Device (50) according to one of claims 1-5, wherein the vent valve (110, 210, 310) is in the closed position when a pressurized cooling lubricant flows along the fluid path (108), and wherein the vent valve (110, 210, 310) is moved into the open position when the pressure in the fluid path (108) drops and falls below a threshold value.

7. Device (50) according to one of claims 1-6, wherein the ventilation valve (110, 210, 310) comprises an actuator (322) which can be coupled to a control device (40, 64) via a control line (324).

8. Device (50) according to claim 7, wherein the actuator (322) is a fluidic actuator or an electromagnetic actuator.

9. Device (50) according to claim 7 or 8, wherein the control device (40, 64) is configured to actuate the actuator (322) to bring the vent valve (110, 210, 310) into the open position when the coolant supply is interrupted and / or the grinding spindle (22) is switched off.

10. Device (50) according to one of claims 1-9, wherein the fluid path (108) extends along a siphon (130), which is formed in particular in the connection block (54, 154).

11. Device (50) according to claim 10, wherein the ventilation valve (110, 210, 310) couples to the fluid path (108) on the outlet side after the siphon (130).

12. Device (50) according to claim 10 or 11, wherein the siphon (130) is a tubular siphon (132) which in particular has an S-shaped course.

13. Device (50) according to one of claims 1-12, further comprising a coolant pump (68) and at least one coolant sensor (58) which can be coupled to a control unit (40, 64) which evaluates the signals of the coolant sensor (58) and operates the coolant pump (68) on this basis in order to deliver a desired quantity of fluid.

14. Grinding machine (10) with a workpiece holder (32) for receiving a workpiece (34) and at least one grinding spindle (22) for receiving a grinding wheel (24), wherein the workpiece holder (32) and the grinding spindle (22) are movable relative to each other in a working space (16) in order to machine a workpiece (34) which is received on the workpiece holder (32), and with a device (50) for dispensing cooling lubricants according to one of claims 1-13.

15. Use of a device according to one of claims 1 to 13 in a grinding machine, in particular in a grinding machine according to claim 14, for dispensing cooling lubricants.

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