WO2018116615A1

WO2018116615A1 - Machine tool

Info

Publication number: WO2018116615A1
Application number: PCT/JP2017/038119
Authority: WO
Inventors: 悠井戸; 宏一郎成松
Original assignee: Dmg森精機株式会社
Priority date: 2016-12-20
Filing date: 2017-10-23
Publication date: 2018-06-28
Also published as: JP6871733B2; JP2018099753A

Abstract

The present invention comprises: a bed (10) that has a plurality of outer surfaces (10a, 10b); and at least one structure (11, 12, 15, … ) that is provided on at least one outer surface (10b) of the bed (10). The present invention is also provided with a blowing device (31) that: blows ambient air along at least the outer surface (10b) of the plurality of outer surfaces (10a, 10b) that has the worst conformity to the temperature of ambient air; and generates a flow of ambient air along said outer surface (10b). The blowing of ambient air along the outer surface (10b) that has the worst conformity encourages heat exchange between said outer surface (10b) and the ambient air and regulates the temperature of said outer surface (10b) such that said temperature becomes the same as the temperature of outer surfaces that have good conformity to the temperature of ambient air. As a result, thermal deformation of the bed (10) can be suppressed, and it is possible to achieve stable machining precision.

Description

Machine Tools

This invention relates to the machine tool which can suppress the thermal deformation by adjusting the temperature of a bed.

A machine tool is generally provided with a bed formed of a casting, and a structure (for example, a headstock in the case of a lathe, which is a main spindle in the case of a lathe) on the bed. In the case of a table), and a structure for holding a tool (for example, a turret in the case of a lathe, a tool spindle in the case of a machining center), and the work holding structure and the tool holding structure. A feeding device that moves relative to the body is disposed on the bed. Then, the workpiece is machined by relatively moving the workpiece and the tool.

By the way, as described above, since the bed is formed of a casting, that is, a metal, it has a characteristic that it is easily deformed by the influence of an external temperature. For this reason, due to this thermal deformation, the relative positional relationship between the workpiece disposed on the bed and the tool is displaced, and this displacement causes a problem that the machining accuracy is deteriorated.

Therefore, conventionally, in order to prevent thermal deformation of the bed, techniques as disclosed in

Patent Documents

1 and 2 below have been proposed. The machine tool disclosed in Patent Document 1 is specifically a lathe, and is provided with bed holes provided horizontally above and below the bed so as to penetrate the bed in the longitudinal direction thereof. Is formed, and the bed holes arranged in parallel vertically through the headstock hole communicate with each other. In addition, a collection duct that collects the mist airflow and guides it to the upper bed hole is provided on the side of the bed.

Thus, according to the machine tool of Patent Document 1, the mist airflow generated during processing is guided from the collection duct to the upper bed hole, and passes through the upper bed hole. Cool the hot part of the bed. Next, the mist air flow enters the headstock hole, cools the high temperature part of the headstock, and heats the low temperature part of the headstock with the amount of heat obtained by cooling. Next, the mist airflow enters the lower bed hole from the headstock hole, passes through this lower bed hole, heats the low temperature part of the bed with residual heat, and then discharges from the bed hole to the outside. Is done. Thereby, the temperature difference of each part in a bed and a headstock is reduced, As a result of suppressing a thermal deformation, it is said that the stable processing precision is obtained.

Further, the machine tool disclosed in Patent Document 2 is also a lathe, and the machine tool includes a ventilation path through which the bed penetrates in the longitudinal direction, and is close to one opening of the ventilation path. Is provided with a blower fan, and further includes means for making the air flow in the ventilation path into a spiral turbulent flow.

According to the machine tool disclosed in Patent Document 2, room temperature air is forcibly taken into the ventilation path of the bed by the blower fan, and the air flow is spirally disturbed by the turbulent flow generation means provided in the ventilation path. By making it a flow, the distance of the flow becomes long and the amount of air hitting the inner wall of the ventilation path increases. As a result, the heat exchange efficiency is enhanced, and the inner wall of the ventilation path is evenly exposed to room temperature air, so that the temperature difference between each part of the bed is reduced.

JP-A-6-155228 JP-A-7-136895

By the way, as a result of earnest, analysis, research, etc., the inventors of the bed constituting the machine tool have different degrees of influence of the ambient temperature depending on the outer surface, and the temperature varies depending on the outer surface. The knowledge that is different. For example, when looking at a lathe, the upper surface of the bed is covered with a cover such as a splash cover for removing chips, and the air trapped between the cover and the upper surface of the bed is hardly exchanged with the outside air. For this reason, the upper surface of the bed is not easily affected by outside air, that is, the temperature of the atmosphere. On the other hand, the back (rear) of the bed is surrounded by a splash guard, but since this area is outside the processing area, the upper part of the splash guard is mostly open. The back surface is easily affected by the ambient temperature.

In this way, each outer surface of the bed has a different degree of influence of the ambient temperature on the relationship with other structures constituting the machine tool, and therefore, the temperature of each outer surface is in a different state. . Therefore, in order to suppress thermal deformation of the bed, it is necessary to adjust this so that the temperature of each outer surface of the bed becomes uniform.

However, in the machine tool disclosed in Patent Document 1 described above, a mist airflow is introduced into the bed, and in the machine tool disclosed in Patent Document 2, room temperature air is also introduced into the bed. As a result, the temperature inside the bed may be substantially uniform, but the temperature is still non-uniform for each outer surface of the bed. That is, as described above, since the influence of the ambient temperature is different on each outer surface of the bed, even if the temperature inside the bed can be made uniform, it has a different temperature gradient between the inside of the bed and each outer surface. The temperature of each outer surface of the bed is not uniform.

Thus, the present inventors have obtained knowledge that it is necessary to directly adjust the temperature of each outer surface of the bed in order to suppress thermal deformation of the bed from the background as described above. is there.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a machine tool capable of suppressing thermal deformation of the bed by adjusting the temperature of the bed outer surface.

The present invention for solving the above problems is a machine tool comprising a bed having a plurality of outer surfaces and one or more structures disposed on at least one of the outer surfaces of the bed,
The present invention relates to a machine tool provided with a blower that feeds the atmosphere along at least the outer surface that has the worst followability to the temperature of the atmosphere among the plurality of outer surfaces and generates an air flow of the atmosphere along the outer surface. .

According to the machine tool configured as described above, the air is sent along the outer surface having the worst followability with respect to the temperature of the atmosphere by the blower, thereby generating an air flow of the atmosphere along the outer surface. And by sending the atmosphere along the outer surface having the worst followability in this way, heat exchange is promoted between the outer surface and the atmosphere, so that the temperature of the outer surface follows the ambient temperature. The temperature is adjusted to be the same as the temperature of the outer surface, which has good followability to the ambient temperature. Thus, according to this machine tool, the temperature of the outer surface of the bed having the worst followability to the ambient temperature can be adjusted to be the same temperature as the temperature of the outer surface having good followability to the ambient temperature. As a result, stable machining accuracy can be obtained.

In addition, as a matter of course, the blower device may be configured to supply the atmosphere along the outer surface other than the outer surface having the worst followability. For example, if each atmosphere is sent along all the outer surfaces of the bed and an air flow of the atmosphere is generated along each outer surface, the entire outer surface of the bed can be adjusted to a substantially uniform temperature, Thermal deformation of the bed can be more effectively suppressed.

Further, the present invention provides the above machine tool,
A control device for controlling the blower;
A first temperature detector for detecting the temperature of the outer surface having the best followability to the ambient temperature;
A second temperature detector for detecting the temperature of the outer surface having the worst followability to the ambient temperature,
The control device is configured to reduce the amount of air supplied by the blower so that a temperature difference between the first temperature detected by the first temperature detector and the second temperature detected by the second temperature detector is small. The present invention relates to a machine tool configured to control an air supply speed.

According to this machine tool, the first temperature of the outer surface having the best followability detected by the first temperature detector and the second temperature of the outer surface having the worst followability detected by the second temperature detector. The control device controls the air supply amount or the air supply speed of the blower so that the temperature difference from the temperature becomes small.

For example, when the difference between the first temperature and the second temperature is large, the air exchange amount (air feed speed) of the blower is increased to exchange heat between the outer surface and the atmosphere having the worst followability. Is adjusted so that the temperature of the outer surface approaches the first temperature of the outer surface having the best followability in a short time. Conversely, when the difference between the first temperature and the second temperature is small, the heat exchange between the outer surface and the atmosphere is in a substantially constant steady state regardless of the amount of air sent from the blower. The amount of air sent from the blower is lowered to the extent that there is no problem with heat exchange, thereby preventing wasteful energy consumption.

Thus, according to this machine tool, the outer surface temperature (second temperature) having the worst followability and the outer surface temperature (first temperature) having the best followability are respectively measured, and these temperatures approach each other. Therefore, the thermal deformation of the bed can be more effectively suppressed, and as a result, more stable processing accuracy can be obtained.

In this machine tool as well, the air blower may be configured so as to send the atmosphere along the outer surface other than the outer surface having the poorest followability. The atmosphere may be supplied along the outer surface. In this case, the temperatures of all the outer surfaces are detected by the temperature detectors, respectively, so that the temperature difference between the outer surface temperature (first temperature) having the best followability and the temperatures of the other outer surfaces becomes small. It is preferable to control the air supply amount or the air supply speed of the outer surface by the control device. In this way, the entire outer surface of the bed can be more accurately adjusted to a uniform temperature, and thermal deformation of the bed can be more effectively suppressed.

As described above, according to the machine tool according to the present invention, the atmosphere is supplied along the outer surface having the worst followability with respect to the atmospheric temperature, so that heat exchange is promoted between the outer surface and the atmosphere. Then, the temperature of the outer surface is adjusted to be the same temperature as the temperature of the outer surface having good followability to the ambient temperature, thereby suppressing thermal deformation of the bed and obtaining stable processing accuracy.

In addition, the first temperature detector detects the outer surface temperature (first temperature) with the best followability, and the second temperature detector detects the outer surface temperature (second temperature) with the worst followability. If the air supply amount or the air supply speed of the blower is controlled so that the temperature difference between the first temperature and the second temperature is small, the temperature of the outer surface with the worst followability is the outer surface with the best followability. Thus, the thermal deformation of the bed is more effectively suppressed and more stable processing accuracy is obtained.

It is the perspective view which abbreviate | omitted a part of splash guard and showed the machine tool which concerns on one Embodiment of this invention. It is the perspective view which abbreviate | omitted and showed all the covers about the machine tool which concerns on this embodiment. It is the block diagram which showed schematic structure of the temperature control apparatus which concerns on this embodiment. It is a graph for demonstrating the effect which the machine tool concerning this embodiment shows. It is a graph for demonstrating the effect which the machine tool concerning this embodiment shows.

Hereinafter, specific embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a perspective view showing a machine tool according to an embodiment of the present invention with a splash guard partially omitted. FIG. 2 is a perspective view showing the machine tool of this example with all covers omitted. FIG. 3 is a block diagram showing a schematic configuration of the temperature adjusting device of this example.

As shown in FIGS. 1 to 3, the machine tool 1 of this example is a lathe, and includes a front cover 2 and a rear cover 4 that form a splash guard, a bed 10, and a first spindle disposed on the bed 10. The base 11, the second spindle base 12, the carriage 15, and the temperature adjustment device 30 are configured.

The first head stock 11 and the second head stock 12 are arranged on the front side of the bed (side on which the operator operates) so that the axes thereof are coaxial and face each other. Are arranged on the left side and the second headstock 12 is arranged on the right side. The second headstock 12 is movable in the Z-axis direction along the axis of the first headstock 11 and the second headstock 12, and the first headstock 12 is appropriately moved by a feeding device (not shown). 11 is advanced and retracted. A workpiece gripping chuck (not shown) is attached to the first spindle stock 11, and a workpiece gripping chuck 13 is similarly attached to the second spindle stock 12.

The carriage 15 is arranged behind the first spindle stock 11 and the second spindle stock 12, and the carriage 15 is moved in the Z-axis direction by a Z-axis feeding device including a servo motor 16. It is supposed to move. The carriage 15 is provided with a saddle 20, and the saddle 20 is moved in the X-axis direction orthogonal to the Z-axis by an X-axis feeding device including a servo motor 17. Further, the saddle 20 is provided with a tool post 21 having a turret 22. The tool post 21 is orthogonal to the Z axis and intersects the X axis by a Y′-axis feeding device including a servomotor 23. It moves in the Y ′ axis direction.

The feeding device (not shown) for moving the

servo motors

16, 17, 23 and the second headstock 12 is controlled by a numerical control device (not shown), and the X-axis feeding device. By the operation of the Y ′ axis feeding device and the Z axis feeding device, the turret 22 moves in the X axis direction, the Y axis direction, and the Z axis direction perpendicular to each other with respect to the first spindle stock 11 and the second spindle stock 12. Moving. Thus, by such an operation, the work (not shown) held on the first headstock 11 and the work (not shown) held on the second headstock 12 are held on the turret 22. Is processed.

The bed 10, the first headstock 11, the second headstock 12, the carriage 15, the saddle 20, the tool rest 21, the turret 22, and the like disposed on the bed 10 are the front cover 2 and the rear cover 4. Covered by a splash guard composed of Further, the machining area of the machine tool 1 is surrounded by appropriate covers including the cover 4 and the door 3 constituting the front cover 2. The upper portion of the rear cover 4 is open.

The temperature adjusting device 30 includes a blower 31, a first temperature sensor 32, a second temperature sensor 33, and a control device 35, as shown in FIG. The blower 31 has a fan and a motor that rotates the fan. As shown in FIGS. 1 and 2, the blower 31 is disposed in the vicinity of the servo motor 16 and sends an atmosphere along the upper surface 10 a of the bed 10. The air flow along the upper surface 10a is generated. Such an air flow promotes heat exchange between the upper surface 10a of the bed 10 and the atmosphere. In addition, in FIG. 1, although the shape of the air blower 31 is illustrated in detail, in FIG. 2, only the external line of the air blower 31 is illustrated for simplification.

The first temperature sensor 32 is a sensor that is disposed on the back surface 10 b of the bed 10 and measures the temperature of the back surface 10 b, and the second temperature sensor 33 is disposed on the top surface 10 a of the bed 10. , A sensor for measuring the temperature of the upper surface 10a.

And the said control apparatus 35 receives the signal which concerns on the temperature (1st temperature) of the said back surface 10b detected and output by the said 1st temperature sensor 32 from the said 1st temperature sensor 32, and said 2nd temperature The blower receives the signal related to the temperature (second temperature) of the upper surface 10a detected and output by the sensor 33 from the second temperature sensor so that the difference between the first temperature and the second temperature is reduced. The rotational speed of the 31 fans is controlled to control the air supply amount (air supply speed).

Specifically, when the difference between the first temperature and the second temperature is large, by increasing the rotational speed of the fan of the blower 31, the air supply amount is increased, and the upper surface 10 a and the atmosphere are increased. By increasing the heat exchange in the meantime, the temperature of the upper surface 10a is adjusted to approach the first temperature of the rear surface 10b in a short time. Conversely, when the difference between the first temperature and the second temperature is small, the heat exchange between the upper surface 10a and the atmosphere is in a substantially constant steady state regardless of the amount of air sent from the blower 31. The rotation speed of the fan of the blower 31 is reduced to the extent that there is no problem with heat exchange, thereby preventing wasteful energy consumption.

In addition, in this example, since the back surface 10b of the bed 10 does not need to cover this strictly, as above-mentioned, the upper part of the rear cover 4 is opened, Therefore, the air in the rear cover 4 is opened. Can be easily interchanged with the outside atmosphere. Therefore, the back surface 10b of the bed 10 is easily affected by the temperature of the external atmosphere, and therefore, the followability to the external atmospheric temperature is good.

On the other hand, since the upper surface 10a of the bed 10 is covered with a splash cover or the like, in the natural state, the air in the splash cover hardly replaces the external atmosphere, and therefore the upper surface 10a has a temperature of the external atmosphere. It is in a state where it is difficult to be affected, and therefore, the followability with respect to the temperature of the external atmosphere is poor.

Thus, in this example, among the outer surfaces constituting the bed 10, the back surface 10 b is in a state that most closely follows the ambient temperature, and the top surface 10 a is in a state that most closely follows the ambient temperature. ing.

In the machine tool 1 of the present example having the above configuration, under the control of the numerical control device (not shown), the operations of the X-axis feeding device, the Y′-axis feeding device, and the Z-axis feeding device, The turret 22 is appropriately moved in the X-axis direction, the Y-axis direction, and the Z-axis direction with respect to the first spindle stock 11 and the second spindle stock 12, and the work held on the first spindle stock 11 by such an operation. (Not shown) or a workpiece (not shown) held on the second headstock 12 is processed by a tool held on the turret 22.

In the machine tool 1, the temperature adjusting device 30 adjusts the temperature of the upper surface 10a of the bed 10 so as to approach the temperature of the back surface 10b. That is, the control device 35 of the temperature adjustment device 30 receives the signal related to the first temperature, which is the temperature of the back surface 10b, output from the first temperature sensor 32, and the upper surface output from the second temperature sensor 33. 10a is received, and the rotational speed of the fan of the blower 31 is controlled so that the difference between the first temperature and the second temperature becomes small, and the air supply amount (send amount) Control air velocity).

The blower 31 takes in an external atmosphere and sends air along the upper surface 10a of the bed 10 to generate an air flow of the external atmosphere along the upper surface 10a. Heat exchange is promoted between 10a and the atmosphere, whereby the temperature is adjusted so that the temperature of the upper surface 10a follows the ambient temperature.

When the difference between the first temperature and the second temperature is large, by increasing the rotational speed of the fan of the blower 31 under the control of the control device 35, the air supply amount is increased, By increasing the heat exchange between the top surface 10a and the atmosphere, the temperature of the top surface 10a is adjusted to approach the temperature of the back surface 10b in a short time.

Conversely, when the difference between the first temperature and the second temperature is small, the heat exchange between the upper surface 10a and the atmosphere is in a substantially constant steady state regardless of the amount of air sent from the blower 31. By reducing the rotational speed of the fan of the blower 31 to the extent that there is no problem with heat exchange, wasteful energy consumption is prevented.

Thus, according to the machine tool 1 of the present example, the temperature (second temperature) of the upper surface 10a of the bed 10 having the worst followability to the ambient temperature in the natural state and the highest relative to the ambient temperature in the natural state. The temperature (first temperature) of the back surface 10b with good followability can be brought close to the same temperature. Thereby, the temperature of the whole outer surface of the bed 10 including the upper surface 10a and the back surface 10b can be leveled, and as a result, thermal deformation of the bed 10 can be suppressed. Then, by suppressing the thermal deformation of the bed 10 in this way, the processing accuracy can be stabilized.

As an example, in the machine tool 1 having the above-described configuration, the atmospheric temperature, the temperature of the back surface 10b of the bed 10, the temperature of the upper surface 10a of the bed 10, and the turret 22 and the first temperature when temperature adjustment by the temperature adjusting device 30 is not performed. FIG. 4 shows changes with time of the displacement between the headstock 11. As shown in FIG. 4, the temperature of the back surface 10b of the bed 10 has better followability to the ambient temperature than the upper surface 10a. In other words, the temperature of the upper surface 10a is less responsive to the ambient temperature than the back surface 10b. For this reason, the bed 10 is largely thermally deformed, and as a result, the displacement between the turret 22 and the first head stock 11 is greatly changed. The displacement is a displacement between a displacement meter attached to the turret 22 and a cylindrical master tool attached to a chuck (not shown) of the first headstock 11. The displacement between was measured. The value was not an absolute value but a relative value indicating the tendency.

In addition, when the temperature of the upper surface 10a of the bed 10 is adjusted by the temperature adjusting device 30 and when the temperature of the upper surface 10a is not adjusted, the displacement with time between the turret 22 and the first headstock 11 is elapsed. The change is shown in FIG. As shown in FIG. 5, when the temperature adjustment of the upper surface 10a is performed, the change in displacement is smaller than when the temperature adjustment is not performed, and by adjusting the temperature of the upper surface 10a, It can be seen that stable machining accuracy can be obtained. Similarly, the displacement in FIG. 5 is also a displacement between a displacement meter mounted on the turret 22 and a cylindrical master tool mounted on a chuck (not shown) of the first headstock 11. Is not an absolute value, but a relative value indicating its tendency.

Thus, according to the machine tool 1 of the present example, the temperature (second temperature) of the upper surface 10a of the bed 10 having the lowest followability with respect to the ambient temperature and the back surface 10b having the best followability with respect to the ambient temperature. The first temperature can be brought close to the same temperature. As a result, thermal deformation of the bed 10 can be suppressed, and the processing accuracy can be stabilized.

As mentioned above, although one Embodiment of this invention was described, the specific aspect which this invention can take is not limited to this at all.

For example, in the above example, one air blower 31 is supplied along the upper surface 10a. However, the present invention is not limited to this, and the air is supplied along the upper surface 10a using a plurality of air blowers 31. Anyway. In this case, the air feeding directions of the blowers 31 are not necessarily the same direction, and may be different directions (for example, directions other than the Z-axis direction).

Further, in the machine tool 1 of the above example, the blower 31 supplies air along the upper surface 10a of the bed 10 having the worst followability with respect to the temperature of the external atmosphere, but is not limited thereto. Other than this, for example, the air may be supplied along the back surface 10b in addition to the front surface and both side surfaces. In this case, it is preferable to provide a blower 31 for supplying air along each surface. Further, a temperature sensor is provided on each surface, and each fan 31 is configured such that the difference between the temperature detected by the first temperature sensor provided on the back surface 10a and the temperature detected by each temperature sensor is reduced. The air supply amount (air supply speed) may be controlled by the control device 35. In this way, the entire outer surface of the bed 10 can be more accurately adjusted to a uniform temperature, and thermal deformation of the bed 10 can be further effectively suppressed.

In the above example, the machine tool 1 is a lathe. However, the present invention is not limited to this, and other machine tools such as a machining center may be used.

In the above example, the control device 35 is separate from the numerical control device (not shown), but is not limited thereto, and the control device 35 is not limited to the numerical control device (not shown). It is good also as a structure built in.

DESCRIPTION OF SYMBOLS 1 Machine tool 2 Front cover 3 Door 4 Rear cover 10 Bed 11 1st spindle base 12 2nd spindle base 15 Reciprocating base 20 Saddle 21 Turret 22 Turret 30 Temperature control device 31 Blower 32 1st temperature sensor 33 2nd temperature sensor 35 Control device

Claims

A machine tool comprising a bed having a plurality of outer surfaces and one or more structures disposed on at least one of the outer surfaces of the bed,
Among the plurality of outer surfaces, there is provided a blower device that feeds the atmosphere along at least the outer surface that has the worst followability to the temperature of the atmosphere and generates an air flow of the atmosphere along the outer surface. Machine tool to do.
A control device for controlling the blower;
A first temperature detector for detecting the temperature of the outer surface having the best followability to the temperature of the atmosphere;
A second temperature detector for detecting the temperature of the outer surface having the worst followability to the temperature of the atmosphere;
The control device is configured to reduce the amount of air supplied by the blower so that a temperature difference between the first temperature detected by the first temperature detector and the second temperature detected by the second temperature detector is small. The machine tool according to claim 1, wherein the machine tool is configured to control an air supply speed.