JP7574168B2 - Coolant supply device and machine tool - Google Patents

Description

The present invention relates to a coolant supply device and a machine tool.

For example, a product (workpiece) machined by an automatic lathe is separated from the raw material, such as a round bar, by a cut-off process. The separated product is then collected in a collection unit arranged at a predetermined position. The collection unit may be, for example, a receiving box (workpiece collection basket) that moves close to the processing point where the cutting edge of the cut-off tool that performs the cut-off process comes into contact with the workpiece and receives the separated workpiece (see, for example, Patent Document 1).

In addition, a technology has been proposed for machine tools that switches the amount of coolant supplied to the machining point between a high flow rate and a low flow rate (see, for example, Patent Document 2).

JP 2000-061704 A Patent No. 5428626

When the workpiece is separated from the material by the above-mentioned cut-off process, the flow of coolant that is sprayed onto the processing point where the cutting edge of the cut-off bit that performs the cut-off process comes into contact with the workpiece may blow the separated workpiece away, making it impossible to collect it in a receiving box or the like provided at the collection position.

The present invention has been developed in consideration of the above circumstances, and aims to provide a coolant supply device and machine tool that can prevent a workpiece that has been separated from a material by a cut-off process from being blown to an unexpected location by the coolant sprayed at the processing point.

The first aspect of the present invention is a coolant supply device used in a machine tool that processes a material held by a spindle while supplying the coolant to a processing point where a tool is brought into contact with the material, the coolant supply device comprising a coolant pump that delivers the coolant, and two independent flow paths that supply the coolant delivered by the coolant pump to the processing point, the coolant pump being switched between on and off depending on the processing step for processing the material, one of the two flow paths having one or two or more pipes arranged in parallel, the other of the two flow paths having a pipe, a storage tank arranged at a position higher than the processing point for storing the coolant supplied from the pipe in the other flow path, and a throttle pipe that throttles the coolant stored in the storage tank and supplies it to the processing point.

The second aspect of the present invention is a machine tool that includes a spindle that holds a material, a tool that is brought into contact with the material held by the spindle at a processing point, a coolant supply device according to the present invention that supplies coolant to the processing point, and a control unit that controls the operation of the spindle, the tool, and the coolant supply device, and the control unit switches between driving and stopping the coolant pump depending on the processing step for processing the material.

The coolant supply device and machine tool of the present invention can prevent the workpiece, which has been separated from the material by the cut-off process, from being blown to an unexpected location by the coolant sprayed at the processing point.

1 is a perspective view showing an automatic lathe, which is an example of a machine tool, including a coolant supplying device, which is an example of a coolant supplying device according to the present invention; FIG. 2 is a perspective view showing a coolant supply device provided in a machining chamber of an automatic lathe. FIG. 2 is a front view of the coolant supply device as seen from the front side of the automatic lathe shown in FIG. 1 . 4 is a flowchart showing the operation of the automatic lathe and the coolant supply device.

The coolant supply device 100 and automatic lathe 200, which are embodiments of the coolant supply device and machine tool according to the present invention, will be described below with reference to the drawings.

(composition)
FIG. 1 is a perspective view showing an automatic lathe 200 including a coolant supplying device 100 which is an example of a coolant supplying device according to the present invention, FIG. 2 is a perspective view showing the coolant supplying device 100 provided in a machining chamber 220 of the automatic lathe 200, and FIG. 3 is a front view of the coolant supplying device 100 as seen from the front side of the automatic lathe 200 shown in FIG. 1.

The automatic lathe 200 shown in the figure is an example of a machine tool according to the present invention. The automatic lathe 200 is a computer-controlled automatic lathe using numerical control, and is equipped with at least a control unit 210, a machining chamber 220 having a front spindle 231, a back spindle 232, and tools 250 (cutting tool, cut-off tool, drill bit, etc.) controlled by the control unit 210, and a coolant supply device 100.

The control unit 210 controls the operation of the front spindle 231, the back spindle 232, the tool 250, and the coolant supply device 100 by executing a preset program.

The front spindle 231 chucks (holds) the round bar, which is the material to be processed, and rotates around its axis (Z-axis), while also feeding in the axial direction and moving in the XY plane (a vertical plane including the X direction (horizontal direction perpendicular to the Z axis) and the Y direction (vertical direction perpendicular to the Z axis)) perpendicular to the axis. In the processing chamber 220, a tool (cutting tool, cut-off tool, drill bit, etc.) appropriate for the processing process is selected from the tools 250, and the selected tool is brought into contact with the round bar to process the round bar.

The rear spindle 232 chucks (holds) the workpiece (the machined part of the round bar) after it has been machined while chucked to the front spindle 231 so as to receive it from the front spindle 231 in the machining chamber 220, and rotates the chucked workpiece around its axis or moves it in a plane perpendicular to the axis.

In this embodiment, as shown in Figures 2 and 3, the chute 240 is fixed to the tip of the rear main shaft 232 (the end opposite the front main shaft 231). The chute 240 is detachable from the rear main shaft 232.

The chute 240 is attached to the back spindle 232 when there is no processing procedure for chucking the workpiece on the back spindle 232, and the workpiece is machined while chucked on the front spindle 231, and the procedure involves recovering the workpiece that has been cut off from the round bar chucked on the front spindle 231 by cut-off processing using a cut-off bit; otherwise, the chute 240 is detached from the back spindle 232.

As shown in Figures 2 and 3, the chute 240 is equipped with a receiving box 241 and an inclined passage 242. The receiving box 241 is open at the top, and its bottom is inclined downwardly toward the rear of the axial direction of the back spindle 232 relative to the horizontal plane, forming a gutter shape with an outlet at the lowest end of the inclined bottom. The receiving box 241 is placed directly below the workpiece that is cut off from the round bar chucked to the front spindle 231 by parting off, and receives the workpiece that has been cut off from the round bar and dropped downward at its bottom through the opening at the top.

The inclined passage 242 is formed like a gutter and is inclined at a predetermined angle to the horizontal plane, with the upper end of the inclination connected to the outlet at the bottom of the receiving box 241. The workpiece received at the bottom of the receiving box 241 reaches the outlet due to the inclination of the bottom, is placed on the inclined passage 242 connected to the outlet, and is transported by moving downward along the inclination of the inclined passage 242.

The coolant supply device 100 is an example of a coolant supply device according to the present invention. The coolant supply device 100 supplies coolant to a processing point P in a processing chamber 220 where a tool 250 contacts a round bar to be processed and processes the round bar. The coolant supply device 100 includes a coolant pump 110, a supply line 120, a first system flow path 130 (an example of one of the flow paths), and a second system flow path 140 (an example of the other of the flow paths).

The coolant pump 110 delivers coolant. The coolant pump 110 is controlled by the control unit 210 to switch between a drive state for delivering coolant and a stop state for stopping the coolant delivery. The control unit 210 controls the switching between drive and stop of the coolant pump 110 depending on the type of processing to be performed on the round bar.

The supply line 120 is connected to the coolant pump 110 and carries the coolant delivered from the coolant pump 110. When the coolant pump 110 stops, the flow of coolant through the supply line 120 also stops.

The first system flow path 130 and the second system flow path 140 are both connected to the supply pipe 120 and supply the coolant delivered by the coolant pump 110 to the vicinity of the processing point P. The first system flow path 130 and the second system flow path 140 are independent of each other.

The first system flow path 130 is composed of, for example, four pipelines 131, 132, 133, and 134. The four pipelines 131 to 134 are the same pipeline, and all of them are flexible. One end (base end) of each pipeline 131 to 134 is connected to the supply pipeline 120, and the other end (tip end) is directed toward the vicinity of the processing point P located below the part connected to the supply pipeline 120.

As a result, each of the pipes 131 to 134 sprays the coolant supplied through the supply pipe 120 near the processing point P.

The first system flow path 130 is not limited to being composed of the four pipelines 131 to 134 described above, but may be composed of one pipeline 131, or may be composed of any number of pipelines greater than or equal to two.

In other words, the first system flow path 130 only needs to be capable of supplying a large amount of coolant near the processing point P, which is suitable for processing other than cut-off processing, in comparison with the coolant supplied from the throttle pipe 144 on the second system flow path 140 side described below.

The second system flow path 140 includes a pipeline 141, an oil tank 142 (storage tank), and a throttle pipeline 144. The pipeline 141 has the same structure as each of the four pipelines 131 to 134 of the first system flow path 130, is flexible, and has one end (base end) connected to the supply pipeline 120 and the other end (tip end) facing the oil tank 142.

Since the pipelines 131, 132, 133, 134, and 141 are identical, it is possible to standardize parts. Since the pipelines 131, 132, 133, 134, and 141 are identical, approximately the same flow rate of coolant flows from the supply pipeline 120 to each of the pipelines 131, 132, 133, 134, and 141. Therefore, the flow rate of coolant in the first system flow path 130 is approximately four times that of the second system flow path 140. The pipelines 131 to 134 and 141 do not need to be flexible.

Note that pipeline 141 does not need to be the same as pipelines 131 to 134, and may be different from pipelines 131 to 134.

The end of the pipeline 141 is directed toward the oil tank 142, so that the coolant that flows through the pipeline 141 is supplied to the oil tank 142.

The oil tank 142 is provided at a position higher than the vicinity of the processing point P. In this embodiment, the oil tank 142 is provided at approximately the same height as the supply pipe 120 or at a position higher than the supply pipe 120, but may be provided at a position lower than the supply pipe 120.

The oil tank 142 stores the coolant supplied from the pipeline 141. A throttle pipeline 144 is connected to the bottom of the oil tank 142 and is located at a lower position than the bottom of the oil tank 142. The throttle pipeline 144 includes a connection pipeline 145, a throttle valve 146, and a drip pipeline 147. The connection pipeline 145 is joined to the bottom of the oil tank 142, and the coolant stored in the oil tank 142 flows into it by gravity.

The throttle valve 146 is connected to the connecting pipe 145 and throttles the flow rate of the coolant that flows through the connecting pipe 145, for example, to a level where it drips drop by drop. The drip line 147 is located below the connecting pipe 145 and the throttle valve 146, with one end connected to the throttle valve 146 and the other end (tip) located above near the processing point P.

As a result, the drip line 147 allows the throttled coolant to drop naturally from the oil tank 142 and drip from its tip to the vicinity of the processing point P. The amount of coolant supplied from the tip of the drip line 147 to the vicinity of the processing point P depends on the degree of throttling of the throttle valve 146. The amount of coolant supplied from the drip line 147 to the vicinity of the processing point P is not limited to an amount dripping drop by drop, but may be an amount that does not blow away the workpiece separated from the round bar material during parting off.

Therefore, the throttle line 144 is not necessarily limited to one equipped with a drip line 147 that drips and supplies the coolant, but may be one that throttles the coolant with a throttle valve 146 to a degree that does not blow away the workpiece (for example, to the extent that the coolant forms thin threads) and supplies it continuously near the processing point P.

As a result, in this embodiment, the amount of coolant supplied from the second system flow path 140 to the vicinity of the processing point P is set to, for example, approximately 1/100 to 1/1000 of the amount of coolant supplied from the first system flow path 130 to the vicinity of the processing point P.

As described above, a large amount of coolant is supplied to the oil tank 142 from the pipeline 141, just like each of the pipelines 131 to 134, but only a very small amount of coolant is discharged from the oil tank 142 through the throttle pipeline 144. Therefore, the balance of coolant entering and leaving the oil tank 142 is an excess supply, and the amount of coolant stored in the oil tank 142 continues to increase. Then, when the coolant stored in the oil tank 142 becomes full, the coolant overflows from the oil tank 142 and flows down from the upper opening.

Here, a notch 143 is formed in the upper edge of the oil tank 142 in the region farther from the processing point P in the X direction. Therefore, the coolant overflowing from the oil tank 142 starts to flow down from the notch 143, so that the coolant that has flowed down from the oil tank 142 can be prevented from falling on the vicinity of the processing point P.

In controlling machining by the automatic lathe 200, the control unit 210 controls the coolant pump 110 so that the coolant pump 110 performs a discharge operation before starting normal machining (a machining process using a tool other than a cut-off bit among the tools 250 (e.g., a cutting process using a cutting bit or a drilling process using a drill bit)) other than cut-off machining (a machining process in which a workpiece is separated from the round bar using, for example, a cut-off bit among the tools 250) on the round bar chucked by the front spindle 231 in the machining chamber 220.

As a result, the coolant pump 110 is driven to start the delivery operation and supply the coolant to the supply pipeline 120. The coolant supplied to the supply pipeline 120 flows into the pipelines 131-134 of the first system flow path 130 and the pipeline 141 of the second system flow path 140. The coolant delivered through the supply pipeline 120 is discharged from each of the ends of the pipelines 131-134 of the first system flow path 130 and the end of the pipeline 141 of the second system flow path 140.

The tips of the pipelines 131-134 of the first system flow path 130 are set to face the vicinity of the processing point P, so that a large amount of coolant is sprayed from the pipelines 131-134 toward the vicinity of the processing point P.

The coolant discharged from the tip of the pipe 141 of the second system flow path 140 is supplied to the oil tank 142, and a very small amount of coolant flows from the oil tank 142 to the drip pipe 147 via the connecting pipe 145 and the throttle valve 146, and a very small amount of coolant drips from the drip pipe 147 near the processing point P.

In this way, before a normal machining process other than cut-off is started, a large amount of coolant from the first system flow path 130 and a very small amount of coolant from the second system flow path 140 are supplied to the vicinity of the machining point P. After that, the control unit 210 controls the front spindle 231 and the tool 250, and the automatic lathe 200 starts the machining operation of the round bar chucked by the front spindle 231 at the machining point P.

During this normal machining process, as described above, a large amount of coolant is supplied near the machining point P to cool the heat generated by machining, wash away chips generated by machining, and reduce friction between the tool 250 and the round bar.

During the normal machining process, the round bar to be machined is chucked to the front spindle 231, so even if a large amount of coolant is sprayed near the machining point P, the round bar will not be blown away by the large amount of coolant sprayed.

On the other hand, when the cut-off process is performed after the normal machining process described above, in which the machined workpiece is separated from the round bar, the control unit 210 controls the coolant pump 110 to stop before starting the cut-off process.

As a result, the coolant pump 110 stops and the supply of coolant to the supply line 120 stops. As a result, no coolant flows through the supply line 120, and no coolant is supplied to the lines 131-134 of the first system flow path 130 and the line 141 of the second system flow path 140. As a result, no coolant is discharged from the ends of the lines 131-134 and 141.

As a result, large amounts of coolant from pipes 131 to 134 are not sprayed near the machining point P.

On the other hand, no coolant is discharged from the tip of the pipe 141 of the second system flow path 140, but a large amount of coolant that would have been discharged from the pipe 141 during the normal processing process is supplied to the oil tank 142 of the second system flow path 140, and since the amount of coolant discharged from the throttle pipe 144 is extremely small, a certain amount of coolant remains in the oil tank 142.

Even when the coolant pump 110 is stopped, the coolant stored in the oil tank 142 is discharged in extremely small amounts through the throttle pipe 144 by natural fall and is supplied to the vicinity of the processing point P.

In this way, during the cut-off process, a large amount of coolant is not supplied near the processing point P, and only a very small amount of coolant is supplied, enough to drip from the drip line 147.

In the parting off process, the workpiece is separated from the round bar chucked to the front spindle 231. If a large amount of coolant, as in a normal machining process, were to be sprayed near the machining point P, the workpiece separated from the round bar would be blown away in an unexpected direction and place by the large amount of coolant sprayed. In particular, if the size of the workpiece is small, the weight of the workpiece is also light, making it more likely to be blown away by the large amount of coolant.

If the workpiece is thrown in an unexpected direction or location like this, there is a risk that the workpiece will not fit into the receiving box 241 that has been placed in advance directly below the processing point P to collect the separated workpiece, and the receiving box 241 will not be able to collect the workpiece.

In contrast, in the cut-off process, the coolant supply device 100 and automatic lathe 200 of this embodiment only supply a small amount of coolant near the processing point P, so that the dripping coolant does not cause the workpiece to fly in an unexpected direction or place.

Therefore, the coolant supply device 100 of this embodiment can collect the workpiece separated by the cut-off process in a receiving box 241 that is placed at a predetermined position.

In this way, the coolant supply device 100 and automatic lathe 200 of this embodiment can switch between driving and stopping the coolant pump 110 depending on the processing step for machining the round bar material, thereby fully utilizing the coolant's functions in the normal processing step while preventing the workpiece from being thrown off in the cut-off processing step.

Note that "depending on the processing process" means "depending on the type and content of processing," for example.

Figure 4 is a flowchart showing the operation of the automatic lathe 200 and the coolant supply device 100. The operation of the automatic lathe 200 and the coolant supply device 100 configured as described above will be explained with reference to the flowchart shown in Figure 4.

The control unit 210 of the automatic lathe 200 reads a preset program, controls the front spindle 231 and the tool 250, and performs normal machining operations on the round bar chucked by the front spindle 231. After the normal machining operations, the machined workpiece is cut off from the round bar by a cut-off operation, and the workpiece is collected by the chute 240. During this series of machining operations, the control unit 210 controls the operation of the coolant supply device 100.

Specifically, as shown in FIG. 4, the control unit 210 of the automatic lathe 200 controls the coolant pump 110 to start the delivery operation (ON) prior to the start of normal machining operations (S1). As a result, a large amount of coolant is sprayed near the machining point P by the first system flow path 130 and the second system flow path 140.

After the coolant pump 110 starts the delivery operation, the control unit 210 controls the operation of the front spindle 231 and the cutting tool, drill bit, etc. of the tool 250 to perform normal machining operations other than parting off on the round bar (S2). When normal machining of the round bar is completed, the control unit 210 controls the front spindle 231 and the tool 250 to stop their operation (S3).

Then, the control unit 210 controls the coolant pump 110 to stop (S4). This stops the discharge of coolant from the lines 131-134 of the first system flow path 130 and the line 141 of the second system flow path 140. However, the coolant stored in the oil tank 142 flows into the throttle line 144, and the coolant drips from the drip line 147 near the processing point P.

Next, the control unit 210 controls the movement of the rear spindle 232 so that the receiving box 241 of the chute 240 is positioned directly below the processing point P where the workpiece is separated from the round bar after normal processing is completed (S5).

Next, the control unit 210 controls the operation of the front spindle 231 and the cut-off tool of the tool 250 to start the cut-off process to separate the workpiece from the round bar (S6). Through the cut-off process, the workpiece is usually separated from the round bar in a very short time (e.g., within 1 second). The control unit 210 controls the front spindle 231 and the cut-off tool to stop operation (S7).

Here, only a very small amount of coolant is supplied near the processing point P, and this coolant suppresses heat generation during the cut-off process and reduces friction between the cut-off tool and the workpiece. On the other hand, the amount of coolant dripped near the processing point P is very small, and moreover, it falls naturally from the drip line 147, so even if it collides with the workpiece separated from the round bar, it does not have enough energy to blow the workpiece away.

Therefore, the workpieces separated from the round bar are collected in the receiving box 241 of the chute 240 regardless of the coolant being supplied near the processing point P. The workpieces collected in the receiving box 241 are then collected in a predetermined position through the inclined passage 242.

Next, the control unit 210 controls the rear spindle 232 to move the receiving box 241 to its original position just below the processing point P, and ends the process.

As described above in detail, the coolant supply device 100 and automatic lathe 200 of this embodiment can prevent the workpiece, which has been separated from the material by the cut-off process, from being blown to an unexpected location by the coolant sprayed near the processing point P.

100 Coolant supply device 110 Coolant pump 130 First system flow path (an example of one of the flow paths)
131, 132, 133, 134, 141 Pipe 140 Second system flow path (an example of the other flow path)
142 Oil tank 144 Restriction pipe 200 Automatic lathe (an example of a machine tool)
231 Front spindle (example of spindle)
250 Tool P Machining point

Claims (5)

The present invention is used in a machine tool that processes a material held by a spindle while supplying a coolant to a processing point where a tool contacts the material,
A coolant pump that delivers the coolant;
and two independent flow paths that supply the coolant pumped by the coolant pump to the processing point;
The coolant pump is switched to a stopped state when the machining process for machining the material is a cut-off process, and is switched to a driven state when the machining process is a process other than the cut-off process ,
One of the two flow paths has one or two or more pipes arranged in parallel,
The other of the two flow paths includes a pipeline, a storage tank located at a position higher than the processing point for storing the coolant supplied from the pipeline in the other flow path, and a throttling pipeline for throttling the coolant stored in the storage tank and supplying it to the processing point. 2. The coolant supply device according to claim 1 , wherein the conduit in the one flow path and the conduit in the other flow path are the same conduit having flexibility . The coolant supplying device according to claim 1 or 2 , wherein the throttle pipe supplies the coolant to the machining point by dripping. The coolant supply device according to claim 1 , wherein the storage tank has a notch formed in an area of an upper edge farther from the machining point in a horizontal direction perpendicular to the main shaft. A main shaft for holding the material;
A tool that contacts the material held by the spindle at a processing point;
A coolant supplying device according to any one of claims 1 to 4 , which supplies a coolant to the machining point;
a control unit for controlling operations of the spindle, the tool, and the coolant supply device,
The control unit switches the coolant pump to a stopped state when the machining process for machining the material is a cut-off process, and switches the coolant pump to a driven state when the machining process is a process other than the cut-off process .