JP2000354931A - Linear motor driving and feeding device for machine tool - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make a linear motor driving and feeding device of a machine tool compact and further prevent thrust required for machining from being reduced. SOLUTION: A moving base 15 supporting a tool G for machining a work piece W is guided and supported to a base 12 so that the moving base 15 may be reciprocated. By a linear motor 16 constituted of a primary motor element 16a and a secondary motor element 16b opposed to each other, the tool G is reciprocated between an advancing position where the tool G is abutted on the work piece W and machining this work piece W and a retreating position where the tool G is separated from the work piece W. Either one of both of the motor elements 16a and 16b is shorter than the other in length of the reciprocating direction. The motor elements 16a and 16b are arranged so as to be completely opposed in the reciprocating direction at the advancing position to be a stroke range to be used for machining of all stroke ranges of the moving base 15 and so as to be partially opposed at the retreating position to be the stroke range which is not used for machining.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a linear motor drive feeder for a machine tool in which a tool is fed to a workpiece by a linear motor in the machine tool.

[0002]

2. Description of the Related Art In a drive feed device such as a machine tool, a linear motor is used to improve feed accuracy and responsiveness. The linear motor used for this is
Normally, the length of the primary motor element (electromagnetic coil) attached to the fixed side is shorter than the length of the secondary motor element (magnet plate) attached to the movable side, and the length of the secondary motor element is the length of the primary motor element. Is equal to or greater than the sum of the stroke lengths. As a result, the primary motor element and the secondary motor element are completely opposed in the entire range of the stroke, so that the linear motor always generates a predetermined thrust.

[0003]

The length of the conventional linear motor drive feeder as described above is governed by the total stroke length and the length of the primary motor element in the reciprocating direction, and is an obstacle to downsizing. It has become. An object of the present invention is to solve such a problem and reduce the size of a linear motor drive feeder of a machine tool.

[0004]

According to a first aspect of the present invention, there is provided a linear motor drive feeder for a machine tool which is guided and supported by a base in a reciprocating manner to support a tool for processing a workpiece, a base, and a movable base. The moving table is comprised of a primary motor element and a secondary motor element which are respectively mounted on the table and oppose each other. The moving table is moved between a forward position where the tool abuts and processes the workpiece and a retracted position where the tool is separated from the workpiece. It has a linear motor that reciprocates and has a primary motor element and 2
One of the lengths of the next motor element in the reciprocating direction is shorter than the other, and the two motor elements are completely opposed in the reciprocating direction at the forward position but only partially opposed at the retracted position. It is characterized by being arranged. The two motor elements of the linear motor are arranged so that they only partially oppose each other in the reciprocating direction at the retracted position where machining by the tool is not performed, so the shorter motor element length and the total stroke length are the same as before. In this case, the length of the longer motor element becomes shorter than before.
In the forward position where machining by the tool is performed, the linear motor generates a predetermined thrust because the two motor elements are completely opposed.

According to a first aspect of the present invention, as described in the second aspect of the present invention, one motor element having a short length is opposed to the other motor element in its entire length at the forward position of the carriage,
In the retracted position, it may be arranged such that a part of the entire length is separated from the other motor element. Even in this way, claim 1
The same operation as described above can be obtained.

According to a second aspect of the present invention, one motor element faces the other motor element over its entire length in the stroke range used for machining, of the entire stroke range of the movable base. In the stroke range not used for machining, one motor element may be arranged such that a part of its entire length is separated from the other motor element. With this configuration, the same operation as the first and second aspects can be obtained.

According to a fourth aspect of the present invention, there is provided a linear motor drive feeder for a machine tool, which is fixedly mounted on the intermediate base and a grinding wheel base which is guided and supported reciprocally by the intermediate base to support a grinding wheel for grinding a workpiece. A linear motor for reciprocating the grindstone head with respect to the intermediate base, comprising a primary motor element and a secondary motor element fixed to the grindstone table so as to face the primary motor element; At the one end position where the grinding wheel is separated from the workpiece in the entire stroke range of the grinding wheel head, a part of the entire length of the primary motor element is disengaged from the secondary motor element, and the grinding wheel At the other end position where the vehicle abuts the workpiece, the primary motor element is arranged so as to face the secondary motor element over its entire length. At the one end position of the stroke of the grinding wheel head where the grinding by the grinding wheel is not performed, a part of the entire length of the primary motor element of the linear motor deviates from the secondary motor element. When the stroke length is the same as the conventional one, the length of the secondary motor element is shorter than the conventional one. Also, at the other end position where the grinding by the grinding wheel is performed, the linear motor generates a predetermined thrust because the primary motor element is opposed to the secondary motor element over its entire length.

According to a fourth aspect of the present invention, as set forth in the fifth aspect, the linear motor reciprocates the grinding wheel base so that the grinding wheel reciprocates in the cutting and feeding direction with respect to the workpiece, and the linear feed direction is perpendicular to the direction. The reciprocating motion of the grinding wheel head may be performed by a feed screw rotated and driven by a transverse feed motor. In this way, the linear motor generates a predetermined thrust at the cutting position where the grinding by the grinding wheel is performed.

[0009]

1 to 3 show an embodiment in which the present invention is applied to a grinder provided with a local cover.
On the bed 10 of this embodiment, a headstock 20 having a chuck 21 for attaching a workpiece W at the tip thereof, a grindstone table (moving platform) 15 having a grinding wheel G for grinding the workpiece W at the tip thereof. Truing device 2 for shaping the grinding wheel G
5, a sizing device 26 for measuring the workpiece W, a tip of the headstock 20 including the workpiece W, a tip of the grinding wheel 15 including the grinding wheel G, a truing device 25, and a local area surrounding the sizing device 26. A cover 30 is provided.

As shown in FIG. 1, a headstock 20 installed on a bed 10 has a horizontal spindle (both not shown) driven to rotate by a spindle motor, and a tip of the spindle is provided with a bearing 20a. A protruding chuck 21 is provided.
A workpiece W of this embodiment is a crankshaft of a rotary compressor including a shaft Wa and two crankpins Wb, and the shaft Wa is coaxially held by a chuck 21 with a main shaft.

As shown in FIGS. 1-3, the grinding wheel base 15
Reciprocating through the fixed base 11 and the intermediate base (base) 12 in the horizontal X direction (cutting feed direction to the workpiece W) orthogonal to the main axis of the headstock 20 and in the Z direction (transverse feed direction) parallel to the main axis. It is supported on a bed 10 if possible. The fixed base 11 fixed on the bed 10 has a Z
An intermediate base 12 guided and supported so as to be able to reciprocate in a direction is supported by a fixed base 11 so as to be rotatable only, and is rotationally driven by a servo motor (lateral feed motor) 14. (Nut) 1 fixed to the lower surface of the nut and screwed into the ball screw 13
It is reciprocated by 3a. As shown in FIG. 3, the intermediate base 12 has a substantially U-shaped cross section extending in the X direction, and its upper side is connected by a motor mounting base 12a. A pair of guide grooves 12 formed on both sides of the inner surface of the intermediate base 12
A pair of rails 15a integrally protruding from both sides of the grindstone table 15 are slidably engaged with b, whereby the grindstone table 15 is guided and supported by the intermediate base 12 so as to reciprocate in the X direction. . The sliding surfaces on the upper and lower sides and both sides between the guide groove 12b and the rail 15a are static pressure guide surfaces, and form static pressure pockets to which pressurized lubricating oil is supplied.

As shown mainly in FIGS. 1 and 2, the grindstone head 15 is integrally formed with a protruding portion 15b that protrudes in the X direction toward the workpiece W gripped by the chuck 21 of the headstock 20. A bearing 1 for rotatably supporting a grindstone shaft (not shown) parallel to the Z direction is provided at the tip of the protruding portion 15b.
5c is fixed. The grinding wheel G attached to one end of the grinding wheel shaft has a cover 22 except for the side facing the workpiece W.
And is rotationally driven by a grindstone motor 19 mounted on the opposite side of the bearing 15c.

As shown mainly in FIGS. 2 and 3, the grindstone table 15 is provided by a linear motor 16 comprising a secondary motor element 16b fixed to the upper surface thereof and a primary motor element 16a fixed to the lower surface of the motor mounting base 12a. The intermediate base 12 is located between a forward position (see the solid line) where the grinding wheel G contacts and grinds the workpiece W and a retracted position (see the two-dot chain line Ga) where the grinding wheel G is separated from the workpiece W. Is reciprocated in the X direction. The primary motor element 16a is an electromagnetic coil, the secondary motor element 16b is a magnet plate, and X
The length in the direction is shorter in the primary motor element 16a than in the secondary motor element 16b. In a state where the grinding wheel head 15 is in the most advanced position (see the solid line in FIG. 2), the primary motor element 16a is opposed to the secondary motor element 16b over the entire length in the X direction, but the grinding wheel head 15 is in the most retreated position (see FIG. 2 (see the two-dot chain line 15d), a part of the front part of the primary motor element 16a is detached from the secondary motor element 16b.
Therefore, the length of the secondary motor element is smaller than the sum of the length of the primary motor element and the total stroke length.

As shown in FIG. 3, a plurality of holes 17a and 17b extending in the X direction are formed in the grindstone table 15 including the protruding portion 15b. The thick hole 17a in the center is the grindstone motor 19
A plurality of small holes 17b are used for supplying lubricating oil to a grindstone shaft provided with a grindstone wheel G or a static pressure guide surface between the intermediate base 12 and the grindstone table 15. is there. A joint 17c for supplying lubricating oil to the hole 17b is provided at the rear end of the grindstone table 15. Coolant for cooling the grinding portion between the grinding wheel G and the workpiece W may be supplied through one of the holes 17b.

The truing device 25 installed on the bed 10 moves the grinding wheel base 15 in the X direction and the Z direction so that the grinding wheel G is positioned at a position shown by a two-dot chain line Gb. This is for shaping the grinding surface of the grinding wheel G. The sizing device 26 includes a support base 26a installed on the bed 10 and a detection head 26b supported by the base 26 so as to be able to move forward and backward. The outer peripheral surface of the crank pin portion Wb of the workpiece W ground by the grinding wheel G. Is measured by indirect sizing or post process.

As shown in FIGS. 1 and 2, the local cover 30 comprises a lower cover 31 fixed on the bed 10 and an upper cover 32 covering the upper side thereof.
Only the portion ahead of the bearing portion 20a, and only the portion of the grinding wheel base 15 beyond the middle of the protrusion 15b are covered with the local cover 30.
Located inside. The lower cover 31 has an upwardly directed flange portion 31a on four sides and a discharge cylinder portion 31b and an opening 31c on the bottom surface. The opening 31c is for mounting the truing device 25 and the sizing device 26 directly on the bed 10. On the lower side of the lower cover 31, a guide gutter 34 that guides the coolant discharged from the discharge cylinder 31b to the storage tank 35 is attached.

The upper cover 32 is for preventing the coolant supplied to the grinding portion from splashing outside, and the lower edge thereof has a flange portion 31 around the lower cover 31 at four sides.
It is fitted inside a. The headstock 20 is configured such that a spindle motor portion for rotating and driving the spindle is located outside the local cover 30, and a portion ahead of the bearing 20 a is inserted into the local cover 30 through an opening provided in the upper cover 32, and the upper cover 3
A seal structure 20b is provided in a portion penetrating through 2 to prevent coolant leakage.

As shown in FIGS. 1 and 2, the projecting portion 15b of the grinding wheel base 15 reciprocating in the X direction slides on a flange member 18b fixed to the local cover 30 of the intermediate base 12 via a plate member 18a. A rectangularly elongated rectangular plate-shaped slide cover 33 is fixed to the flange member 18b so as to be movably penetrated. Also, on the rear surface of the local cover 30 on the intermediate base 12 side, the Z of the intermediate base 12 is provided.
A rectangular opening 30a having a length allowing the reciprocating movement of the flange member 18b accompanying the reciprocating motion in the direction is formed, the lower edge thereof is formed by the upper edge of the flange portion 31a of the lower cover 31, and the upper edge and both side edges are formed. It is formed by the rear surface of the upper cover 32. The slide cover 33 slidably abuts the lower edge portion on the inner surface of the flange portion 31a, and the upper edge portion and both side edge portions slidably abut on the rear surface of the upper cover 32, and reciprocates with the intermediate base 12 in the Z direction. In this case, the length is set such that the opening 30a is always kept closed in the entire range of the stroke. These plate member 18a, flange member 18b, opening 30a and slide cover 33
The projecting portion 15b of the grindstone base 15 constitutes a sliding seal structure A for preventing coolant from leaking from an insertion portion inserted into the local cover 30.

Inside the local cover 30, there is provided a hollow column 36 which rises from the lower cover 31 for passing wiring for the truing device 25 and the sizing device 26 and a pipe for supplying coolant adjusted to the grinding portion. I have.

In the processing standby state, the grindstone table 15 is at the rearmost position shown by a two-dot chain line 15d in FIG.
The primary motor element 16a of No. 6 has a part of the front part separated from the secondary motor element 16b. From this state, the control device that controls the operation of the grinding machine advances the grinding wheel head 15 in the X direction by the linear motor 16 and the one of the crank pin portions Wb of the rotating workpiece W gripped by the tip of the main shaft. The rotating grinding wheel G is brought into contact with the outer peripheral surface, and the grinding wheel base 15 is reciprocated in conjunction with the rotation of the main shaft to perform grinding. Whetstone stand 15
The primary motor element 16a always faces the secondary motor element 16b over the entire length in the X direction at least in the range used for this grinding process in the stroke (see the solid line in FIG. 2).

After grinding one crank pin portion Wb by a predetermined amount, the control device retracts the grindstone table 15 once, stops the main shaft at a predetermined angular position, and advances the detection head 26b of the sizing device 26, The feeler at the tip is brought into contact with the outer peripheral surface of the ground crank pin Wb to measure the dimension.
Then, the remaining grinding amount is calculated, the grinding is performed again, and the crankpin portion is ground with a predetermined accuracy. Note that the wheel head advance position at this time is stored. Next, the grindstone table 15
Is moved in the Z direction together with the intermediate base 12 so that the grinding wheel G faces the other crankpin portion Wb, and the grinding wheel base 15 is advanced in the X direction in the same manner as described above, so that the outer peripheral surface of the other crankpin portion Wb. Grinding. At this time, the other crankpin portion is ground with a predetermined accuracy by performing the grinding process until the one of the crankpin portions comes to the grindstone position at the time of completion of the grinding. After processing is completed, the workpiece W is
Is removed, the unprocessed workpiece W is gripped, and grinding is performed in the same manner as described above. Note that a sizing device may be provided at a position facing each pin in order to realize more accurate processing. Alternatively, the sizing device may be moved in the Z-axis direction according to the processing location.

A coolant whose temperature is controlled is supplied to each grinding portion between each crank pin portion Wb and the grinding wheel G through two pipes introduced from the hollow column 36 into the local cover 30. The temperature rise of the workpiece W and the grinding wheel G due to heat generated during processing is prevented. The used coolant that has flowed downward enters the lower cover 31 and is returned from the discharge cylinder portion 31b into the storage tank 35 through the guide gutter 34.

Each time the machining of a predetermined number of workpieces W is completed,
The grinding wheel base 15 is moved in the X direction and the Z direction to position the grinding wheel G at the position of the two-dot chain line Gb (see FIG. 1), and the truing device 25 is operated to shape the ground surface of the grinding wheel G by the truer 25a.

According to the above-described embodiment, the grinding wheel head 15
Is in the retracted position, a part of the front part of the primary motor element 16a is disengaged from the secondary motor element 16b, and the length of the longer secondary motor element 16b becomes shorter than before, so that The total length of the linear motor 16 can be shortened by that much, and the linear motor drive feed device of the machine tool can be made compact. In addition, at the forward position of the grindstone table 15, which is the stroke range in which the grinding is performed, the primary motor element 16a faces the secondary motor element 16b over the entire length in the X direction, and the linear motor 16 generates a predetermined thrust. There is no shortage of thrust.

As in the above-described embodiment, a pair of rails 15a integrally projecting from both sides of the grindstone table 15 into a pair of guide grooves 12b formed on both sides of the inner surface of the intermediate base 12.
Is slidably guided and supported, the load due to the weight of the grindstone base 15 and each member attached thereto is applied to the lower one of the sliding surfaces between the guide groove 12b and the rail 15a. The sliding surface wears first and the upper sliding surface wears less. On the other hand, since a magnetic attraction force acts between the primary motor element and the secondary motor element of the linear motor that reciprocates the grinding wheel head, if this linear motor is provided below the grinding wheel head 15, Load on the sliding surface of
Therefore, the thrust of the linear motor cannot be increased. However, in the above-described embodiment, since the linear motor 16 for reciprocating the grindstone head 15 is provided between the grindstone head 15 and the motor mounting base 12a located above the grindstone head 15, the linear motor 16 is generated between the two motor elements 16a and 16b. The magnetic attraction pulls up the grindstone table 15 and acts to reduce the load applied to the lower sliding surface. Therefore, linear motor 1
6, and the frictional resistance and wear of the sliding surface can be reduced.

In the above embodiment, the case where the linear motor drive feeder of the machine tool according to the present invention is applied to the cutting feed of the grinding machine has been described, but the present invention is not limited to the lateral feed of the grinder and other tools of the machine tool. It is also possible to apply it to the sending of the paper.

[0027]

According to the first aspect of the present invention, the length of the longer motor element is shorter than that of the conventional motor element, so that the overall length of the linear motor can be shortened accordingly, and the linear motor drive of the machine tool can be shortened. The feeder can be made compact and the linear motor generates a predetermined thrust at the forward position where machining by a tool is performed, so that there is no shortage of thrust required for machining.

In the second and third aspects of the present invention,
Similar to the first aspect of the present invention, the linear motor drive feeder of the machine tool can be made compact, and the thrust required for processing does not run short.

According to the fourth aspect of the present invention, since the length of the secondary motor element is shorter than in the prior art, the total length of the linear motor can be shortened accordingly, and the linear motor drive feed of the machine tool can be shortened. The linear motor generates a predetermined thrust at the end position where the grinding operation is performed by the grinding wheel, so that the thrust required for the grinding operation is not insufficient.

According to the fifth aspect of the invention, similarly to the fourth aspect of the invention, the linear motor drive feeder of the machine tool can be made compact, and the thrust required for grinding at the cutting position is insufficient. There is no.

[Brief description of the drawings]

FIG. 1 is an overall plan view of a machine tool provided with an embodiment of a linear motor drive / feed device according to the present invention.

FIG. 2 is a cross-sectional view along a X direction showing a main part of the linear motor drive / feed device of the machine tool shown in FIG.

FIG. 3 is an enlarged sectional view taken along line 3-3 in FIG. 2;

[Explanation of symbols]

12: base (intermediate base), 13: feed screw (ball screw), 14: lateral feed motor (servo motor), 15 ...
Moving table (grinding wheel), 16: linear motor, 16a: primary motor element, 16b: secondary motor element, G: tool (grinding wheel), W: workpiece.

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 3C034 AA20 BB32 DD20 3C048 AA01 BB01 BC01 DD01 DD06 DD26 5H641 BB18 BB19 GG01 GG02 GG12 HH01 HH03 HH14 JA10

Claims (5)

[Claims] 1. A moving table for supporting a tool for processing a workpiece which is guided and supported reciprocally by a base, and a primary motor element and a secondary motor element which are respectively attached to the base and the moving table and face each other. A linear motor that reciprocates the movable table between a forward position where the tool abuts and processes the workpiece and a retreat position where the tool is separated from the workpiece; One of the lengths of the next motor element and the secondary motor element in the reciprocating direction is shorter than the other, and both motor elements are completely opposed in the forward position in the reciprocating direction, but are not in the other positions. A linear motor drive feeder for a machine tool, wherein the linear motor drive feeder is arranged so as to face only partially. 2. The one motor element having a short length is opposed to the other motor element in its full length at the advance position of the moving table, and a part of its full length is at a retracted position from the other motor element. The linear motor drive feeder for a machine tool according to claim 1, wherein the linear motor drive feeder is arranged so as to be disengaged. 3. The one motor element is opposed to the other motor element in its entire length in a stroke range used for machining out of a full stroke range of the movable base, and the one motor element is in a stroke range not used for machining. 3. The element according to claim 1, wherein the element is arranged so that a part of its entire length is separated from the other motor element.
4. A linear motor drive feeder for a machine tool according to claim 1. 4. A grindstone table which is guided and supported by an intermediate base so as to be able to reciprocate and supports a grinding wheel for grinding a workpiece, a primary motor element fixed to said intermediate base, and said grindstone table so as to face the same. A linear motor for reciprocating the grindstone head with respect to the intermediate base, wherein the length of the primary motor element in the reciprocating direction is shorter than that of the secondary motor element. And at the one end position where the grinding wheel is separated from the workpiece in the entire stroke range of the grinding wheel head, a part of the entire length of the primary motor element is separated from the secondary motor element,
A linear motor drive feed device for a machine tool, wherein the primary motor element is disposed so as to face the secondary motor element over its entire length at the other end position where the grinding wheel contacts the workpiece. 5. The linear motor reciprocates the grinding wheel head so that the grinding wheel reciprocates in a cutting and feeding direction with respect to the workpiece. The linear motor drive feed device for a machine tool according to claim 4, wherein the feed is performed by a feed screw rotated and driven by a feed motor.