JPH1133892A - Machine tool with a pair of rest devices - Google Patents

Abstract

(57) [Problem] To provide a rest device system which can support a processing portion or a cylindrical portion at both ends thereof with high rigidity and is versatile and full of flexibility. SOLUTION: A table 14 on which a pair of workpiece supporting devices 20 and 21 are placed is provided so as to be indexable in a longitudinal direction, and the workpieces W are rotatably supported at both ends by the supporting devices 20 and 21.
In a machine tool in which at least one of the processing portions C1 to C8 is selectively indexed in front of the tool G, a pair of rest devices 51 and 52 are provided on the table 14.
It is provided so that it can be individually positioned and indexed in its longitudinal direction,
The journals at both ends of each processing part are paired with a pair of rest devices 51,
52. A pair of rest devices 5
Feed screws 36a and 36b for positioning and feeding the workpieces 1 and 52 extend through the tunnel 32 formed in one of the workpiece support devices 21 and extend to the rear side of the workpiece support device 21. On the rear side, a drive servo is provided. The motors 46a and 46b were connected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rest device for preventing a workpiece from being bent by machining resistance when machining a rod-shaped workpiece rotatably supported by a pair of workpiece support devices at both ends in a longitudinal direction. And more preferably to a grinding machine.

[0002]

2. Description of the Related Art In general, when grinding a plurality of processing locations separated in the longitudinal direction of a bar-shaped workpiece, a shoe of a rest device is brought into contact with a processing location to be ground by a grindstone. The rest device is installed on the bed of the grinding machine such that the position in the longitudinal direction with respect to the grindstone is kept constant regardless of the indexing operation in the longitudinal direction of the table supporting the workpiece.

[0003] Japanese Patent Application Laid-Open No. 2-76655 shows an example of a type of rest device installed on a bed of a grinding machine. In this apparatus, the rest device is made slightly movable in the longitudinal direction of the table by using the movement of the table in order to remove the contact position of the rest shoe from the position of the hole opened to the processing location. In addition, Japanese Utility Model Laid-Open No. 4-115567 and
No. 115568 is provided with a plurality of rest devices on a table so as to simultaneously support all journals adjacent to a plurality of cams to be machined on a camshaft during grinding. In the device disclosed in Japanese Utility Model Laid-Open No. 4-115567, a plurality of rest devices are placed and fixed on a single slide that can move a certain distance in a longitudinal direction on a table,
It is possible to cope with a similar camshaft in which the chuck position on the headstock and the first journal position are slightly different by moving the slide a small distance.

On the other hand, in the apparatus disclosed in Japanese Utility Model Laid-Open Publication No. 115568, a movable two-dimensionally movable table on a table.
By providing two slides and providing a slight difference in the amount of movement between the two slides, the same apparatus can be used for processing similar camshafts having different journal pitches against which the rest shoes abut.

[0005]

However, in a device in which the rest device is installed on a bed, the mounting position of the rest device on the bed and the work supporting position of the rest shoe are greatly separated over the table. This is disadvantageous in terms of supporting rigidity. In addition, the above-described device of the type in which the rest shoe abuts at a position adjacent to each of the plurality of processing locations on the workpiece has limited flexibility such that it can cope with similar workpieces, but the longitudinal direction of the plurality of processing locations It is not possible to cope with a workpiece having a significantly different arrangement in the.

SUMMARY OF THE INVENTION Accordingly, it is a main object of the present invention to provide a machine tool having a highly flexible rest device which has a large supporting rigidity and can cope with various works. Further, in the above-described type in which the rest device is arranged on the table via the slide, the driving source for moving the slide is arranged in the machining area between the headstock and the tailstock, so that grinding dust is always generated. And contamination by the coolant, and the workability in maintenance and inspection and maintenance is poor.

[0007] Therefore, another object of the present invention is to provide a drive source for positioning the rest device in the longitudinal direction outside the processing area to reduce malfunctions and facilitate maintenance and inspection and maintenance.

[0008]

The above-mentioned problems relating to the conventional apparatus and the object of the present invention are solved and achieved by the following means. In the present invention, as described in claim 1, a table on which a pair of workpiece supporting devices for rotatably supporting a workpiece is placed is moved and positioned in the longitudinal direction, and the table is placed in front of a tool on the workpiece. A machine tool configured to index at least one machining location and to advance and retreat the tool in a direction transverse to the longitudinal direction to machine the machining location, wherein a guide way extending in the longitudinal direction is formed. A member is provided on the table, and the pair of rest devices are guided along the guideway so as to be position-adjustable in the longitudinal direction, and further, the pair of rest devices are individually positioned independently in the longitudinal direction. A driving device is provided.

With this configuration, the vicinity of both sides of at least one processing portion can be firmly supported by the pair of rest devices, and the processing accuracy can be improved. In addition, since the pair of rest devices can be individually positioned on the table, a workpiece having a different longitudinal position of a processing location, a workpiece having a different width in the longitudinal direction of the processing location, and a plurality of processing locations in the longitudinal direction. It is possible to flexibly cope with arranged workpieces.

In the invention described in claim 2, a pair of feed screws are provided between a pair of guide ways formed on the guide member so as to be separated in a direction crossing the longitudinal direction, and the feed screws are connected to the pair of guide screws. One end of each screw is screwed into each nut of the rest device, and one end of the nut is inserted through a tunnel formed in one of the workpiece support devices to extend to the back side of the one work support device, and these feed screws are individually rotated. A driving motor to be driven is disposed outside a processing area between the pair of workpiece support devices. As a result, the drive motor is free from contamination from machining chips and coolant, and the number of failures of the drive motor is reduced, and maintenance and inspection and maintenance are facilitated.

According to the third aspect of the present invention, a part of the guide member is inserted into the tunnel, and the guide provided between the one workpiece support device and the rest device on the support device side. The way is configured to be covered with one cover. This eliminates the cost and functional disadvantages associated with bellows and telescopic covers conventionally used as this type of cover.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a plan view of a main part of a cam grinder as an example of a machine tool according to the present invention. In the figure, a base 10 of a grinding machine guides a grindstone table 12 so as to be able to advance and retreat along a pair of guide surfaces 11a and 11b on a rear upper surface, and a table 14 along a pair of guide surfaces 13a and 13b on a front upper surface. Its longitudinal direction, that is, the grinding wheel head 12
Are guided so as to be able to move left and right in a direction perpendicular to the direction of movement.

The table 14 is, as shown in FIG.
A nut 15 fixed to the lower surface is screwed with a feed screw 16. A servo motor 17 fixed to the left end of the base 10 in FIG. 1 rotates the feed screw 16 to move the table 14 in its longitudinal direction, and can position the table 14 with respect to the grinding wheel G which is rotatably supported by the grinding wheel table 12. The headstock 2 mounted and fixed on the table 14 while being spaced apart in the longitudinal direction
The 0 and the tailstock 21 constitute a pair of workpiece support devices that support both ends of a bar-shaped workpiece W (see FIG. 2) described later. The headstock 20 rotatably supports the chuck 22 around an axis parallel to the moving direction of the table 14 on a side facing a processing area defined between the headstock 20 and the tailstock 21. A drive motor (not shown) is provided to rotationally drive the chuck 22. The chuck 22 supports one end of the workpiece W at the center 23 and can clamp the workpiece W, and drives the workpiece W to rotate.

The tailstock 21 is provided with a tailstock ram 25 on the table 1.
4 so that it can advance and retreat only in the moving direction. A center holder 26 is fixed to the tip of the tailstock ram 25, and the holder 26 fixedly supports the center 27 concentrically with the center 23 of the headstock 20. A guide member 30 extending in the longitudinal direction of the table 14 is fixedly provided on the table 14 at a substantially central portion in a direction orthogonal to the longitudinal direction. The guide member 30 has a left end in FIG.
The right end extends into a tunnel 32 formed on the lower surface of the tailstock 21.

The guide member 30 has a pair of guideways 30a, 30b spaced apart in a direction perpendicular to the longitudinal direction of the guide member 30 over its entire length.
The channel 30c (FIG. 2)
Reference). The pair of slides 33 and 34
It is slidably guided in the longitudinal direction along the guideways 30a and 30b. A pair of feed screws 36a and 36b are accommodated in the channel 30c in parallel, and these feed screws 36a and 36b are rotatably supported by bearing members 37 and 38 fixed to both ends of the guide member 30, respectively.

The feed screw 36a is screwed with a nut 39a fixed to the lower surface of the slide 33 on the headstock 20 side.
On the other hand, the feed screw 36b is screwed with a nut 39b fixed to the lower surface of the slide 34 on the tailstock 21 side. The right ends of the feed screws 36a and 36b pass through the bearing member 38, extend to the back side opposite to the processing area side of the tailstock 21, and advance into the gear box 45 fixed to the upper surface on the right end side of the table 14. doing. Gear box 45
Has a pair of servo motors 46a, 46b fixed to its right end face, and the output shafts of these servo motors 46a, 46b are gear-coupled to feed screws 36a, 36b, respectively, inside thereof.

The slides 33 and 34 have resting devices 51 and 52 mounted and fixed on the upper surfaces thereof, respectively. These rest devices 51, 52 are of the same construction, each of which is of a known type in which three rest arms 53a, 53b, 53c (see FIG. 2) are driven by a servomotor 54 fixed to the rear surface on the front side. . More specifically, as shown in FIG. 2, the horizontal arm 53a opposes the bending stress in the direction in which the workpiece W separates from the grindstone G by the grinding resistance, and the upper and lower arms 53a.
b and 53c oppose the vertical bending stress acting on the workpiece W due to the grinding resistance. These three arms 53a-53
The tip of b is driven by the servomotor 54 so as to maintain the same distance from the ideal rotation center line connecting the pair of centers 23 and 27 as the other. Thereby, during the grinding operation, the workpiece W is held so as to rotate on the ideal rotation center line.

Each of the slides 33 and 34 has a built-in play mechanism (not shown) that is driven by an actuator 56a to draw the corresponding slide in a direction away from the grindstone G, and is driven by an actuator 56b. A well-known clamp mechanism (not shown) for pressing a corresponding slide onto the guide member 30 is incorporated. The rattling mechanism and the clamp mechanism are sequentially operated immediately after the corresponding slide is positioned at the target position, and the rest device on the slide is moved to the guide member 30.
Can be firmly fixed on top. The actuators 56a and 56b are constituted by, for example, hydraulic cylinders.

Further, as shown in FIG. 2, the slides 33 and 34 project telescopically overlapping covers 59 and 60 at their adjacent portions toward the slides of the other party, respectively. It corresponds to a predetermined amount of relative distance change between them.
The slide 33 is fixed to a single plate cover 62 for preventing the guide member 30 from being exposed on the headstock 20 side. The left portion of the single plate cover 62 passes through the tunnel 31 of the headstock 20. On the other hand, the slide 34 is fixed to a single plate cover 63 for preventing the guide member 30 from being exposed on the tailstock 21 side, and the right end of the cover 63 is connected to the tunnel 3 of the tailstock 21.
2 can be penetrated.

FIG. 3 is an explanatory view showing a case where the grinding machine of the above-described embodiment grinds a camshaft for a 4-port, 16-valve engine as a typical example of the bar-shaped workpiece W. FIG. 4 shows the grinding of this camshaft. 6 is a flowchart showing a control program executed by a not-shown CNC device for executing the control program. By executing this control program, the CNC device controls the servomotors 17, 46a, 46b, 54 and a servo motor for feeding a wheel head (not shown), and the actuators 56a,
A switching valve (not shown) for 56b is controlled. Hereinafter, the operation of the embodiment will be described with reference to FIGS.

When the support of the camshaft W to the centers 23 and 27 is completed, the CNC device executes the control program shown in FIG. First, in step S1, the cam designation counter N is set to an initial value "1", and the chuck 22 clamps the left end of the cam shaft W in step S2. In step 3, it is determined whether the cam designation counter N has completed the processing of all the cams C1 to C8.
In this case, step S4 is executed and the servo motor 17
Is driven, the table 14 moves from an unillustrated original position, and the first cam C1 is indexed on the front surface of the grindstone G.

In the next step S5, the servo motors 46a and 46b are driven, and the rest devices 51 and 52 are indexed in front of the first and second journals J1 and J2 and near the first cam C1. Upon completion of the indexing, step S6 is executed, and the actuators 56a, 56
The loose play mechanism and the clamp mechanism (not shown) are sequentially operated by 6b, whereby the slides 33 and 34 on which the rest devices 51 and 52 are integrally mounted are firmly fixed on the guide member 30.

In step S7, each of the rest devices 5
1 and 52 advance the three rest arms 53a to 53c from the release position to the restraining position shown in FIG. 2 by the operation of the servomotor 54, and the corresponding journals J1 and J2 are moved by these arms.
Is supported at three points. The supporting positions on these journals are set so that they are on both sides close to the cams C1 and C2 to be machined.
Specified on the C program. Each journal J1
J5 are processed in advance and prepared for support by abutment of the rest arms 53a to 53c.

Thereafter, in step S8, the camshaft W is driven to rotate together with the chuck 22, and at the same time, the grindstone table 12 is advanced by the operation of a servo motor (not shown) to engage the grindstone G with the first cam C1. Grind cam. During the grinding of the cam, as is well known, the chuck 2
In accordance with the rotational position of 2, the forward / backward movement of the grinding wheel head 12 for cam generation is superimposed on the cutting forward movement of the grinding wheel head 12 with respect to the cam. In this case, the first cam C1 is ground in a state where the journals J1 and J2 on both sides thereof are firmly supported at three points by the rest arms 53a to 53c at positions close to the first cam C1, so that the entire camshaft W is formed. In spite of low rigidity, highly accurate cam grinding is realized.

When the machining of the first cam C1 is completed, in step S9, the chuck 22 and the camshaft W
Next, the processing is stopped at an angular position where the base circle portion of the second cam C2 to be processed faces the grindstone G, and at the same time, the grindstone table 12 is retracted. In the next step S10, the cam designation counter N
"1" is added to the second cam C2.
Is specified as A step S11 decides whether or not the content of the cam designation counter N is an even number. As a result of the decision, a step S12 is executed. Thereby, the table 14 is shifted leftward in FIG. 3 so as to position the second cam C2 in front of the grindstone G.

When the table shift is completed, steps S8 to S11 are sequentially executed, and as a result, the second cam C
2 is ground in the same manner as the first cam C1. In step 11, in this case, it is determined that the cam designation counter N designates the odd-numbered cam, so the rest arms 53a to 53c are retracted to the release position in step S13, and the slides 33 and 34 are rattled. The mechanism and the clamp mechanism are both unclamped and the rest devices 51, 52
Prepare for indexing operation.

Subsequently, steps S3 to S12 are sequentially executed, and the indexing operation of the table 14 for positioning the third cam C3 in front of the grinding wheel G, the second and third journals J2, J
(3) Indexing operation of the rest devices 51 and 52 to the front, clamping operation of the slides 33 and 34 with respect to the guide member 30,
Forward movement of rest arms 53a-53c to restraint position, third
The grinding operation of the cam C3 is sequentially performed.

Thus, the first cam C1 to the eighth cam C
8, each of the journals on both sides rests 53a-53c
When the machining of the eighth cam C8 is completed, the determination in step S3 becomes Yes, and the table 14 and the rest devices 51 and 52 return to the original positions in the longitudinal direction of the table 14 in step S15. Then, the processing of the camshaft W is completed.

In the above-described embodiment, an example has been described in which the camshaft W having a plurality of cams C1 to C8 to be machined in the longitudinal direction is machined. The present invention can also be used when a plurality of workpieces having (for example, C1) at the same or different longitudinal positions are sequentially loaded / unloaded and processed. in this case,
A single machined portion on each workpiece is machined with machined shafts on both sides thereof supported by a pair of rest devices 51,52.

In the above-described embodiment, a grinding machine has been exemplified. However, a milling cutter having a plurality of cutting tools provided on a circumference of a disk-shaped tool can be used to cut a processed portion having a perfect circle or a non-true circle in cross section. The present invention can also be applied to a machine tool for cutting. Further, the present invention provides a cylindrical processing portion having a relatively long longitudinal direction, and a pair of rest devices 5 at both ends on the cylindrical portion.
The present invention may also be applied to a case where grinding or cutting is carried out while being supported by 1, 52.

[0031]

As described in detail above, according to the first aspect of the present invention, a pair of rest devices are provided on a table capable of indexing a processing position of a bar-shaped workpiece to the front of a tool. The versatility of the rest device is improved because the position is independently adjustable in the longitudinal direction so that the pair of rest devices can cope with various bar-shaped workpieces having one or more processing locations. Needless to say, the processing portion of the bar-shaped workpiece or the cylindrical portions on both sides in the vicinity of the processed portion can be strongly supported by the pair of rest devices, whereby even when the rigidity of the bar-shaped workpiece is small, The processing location of this workpiece can be processed with high precision. In particular, when processing a camshaft having a plurality of cams formed as processing positions, the journal portions located on both sides of each cam and the portions near the cams are firmly supported by a pair of rest devices and processed. Therefore, it is possible to greatly improve the processing accuracy in cam processing in which the fluctuation of the processing resistance is large, and it is possible to cope with camshafts of various specifications having different overall lengths in the longitudinal direction, cam positions, pitches between cams, etc. Manufacturing costs can be reduced as compared with a case where a dedicated rest device system is manufactured according to the specifications of the shaft.

According to the second aspect of the present invention, a pair of feed screws constituting a positioning drive device for a pair of rest devices are attached to at least one of a pair of workpiece support devices supporting both ends of the workpiece. The feed screw is individually driven to the back side of the one workpiece support device, which is separated from the work area by the one workpiece support device, through the formed tunnel. Since the motors are arranged, these motors are prevented from being contaminated by machining chips and coolant generated in the machining area. As a result, not only can the operation reliability of the rest device system be improved, Maintenance and inspection work of the system becomes easy.

Further, according to the third aspect of the present invention,
The protective cover of the slide member fixed to one of the rest devices located closer to the at least one work support device can be advanced into the tunnel so that the cover can be used as a single cover. Compared with the bellows-type cover and the telescopic-type cover, a practical effect of achieving reliable covering at low cost can be obtained.

[Brief description of the drawings]

FIG. 1 is a plan view of a main part of a camshaft grinding machine as an embodiment of a machine tool having a pair of rest devices according to the present invention.

FIG. 2 is a sectional view taken along the line II-II in FIG.

FIG. 3 is an explanatory view showing a camshaft support system to be ground by the camshaft grinding machine of FIG. 1;

FIG. 4 is a flowchart of a control program executed by a CNC device (not shown) for processing the camshaft illustrated in FIG. 3;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 10 ... Base 12 ... Grindstone G ... Grindstone W ... Camshaft 14 ... Table 16 ... Table feed screw 17 ... Servo motor 20 ... Headstock 21 ... Tailstock 51, 52 Rest device 30 Guide member 39a, 39b Nut 31, 32 Tunnel 33, 34 Slide 36a, 36b Slide feed screw 46a, 46b ... Servo motors 62, 63 ... Cover

 ──────────────────────────────────────────────────続 き Continuing from the front page (72) Inventor Hisashiri Kobayashi 1-1-1, Asahi-cho, Kariya-shi, Aichi Pref.

Claims (3)

[Claims] 1. A base, a table movable on the base in a longitudinal direction, and a pair of workpiece support devices fixed on the table at a distance in the longitudinal direction and rotatably supporting a bar-shaped workpiece. A tool table that supports a tool and is advanced and retracted in a direction transverse to the longitudinal direction, and the table in the longitudinal direction for selectively indexing at least one machining point on the workpiece to the front of the tool. In a machine tool comprising: a table feed device for positioning; and a rest device for supporting the workpiece against a machining resistance while the at least one machining portion is machined by the tool, the guide way extending in the longitudinal direction is provided. The formed guide member is provided on the table, and the rest device can simultaneously support the workpiece near both ends in the longitudinal direction of each processing location of the workpiece. In order to do so, a pair of rest devices can be individually adjusted in the longitudinal direction along the guideway, and furthermore, the pair of rest devices are adjusted to the longitudinal position and width of each of the processing locations. A machine tool provided with a pair of rest devices, further comprising a positioning drive device that performs independent positioning in the longitudinal direction according to the position. 2. The machine tool according to claim 1, wherein at least one of the pair of workpiece support devices is formed with a tunnel penetrating in the longitudinal direction from the workpiece support side to the opposite back side. The positioning drive device extends in the longitudinal direction between a pair of guideways rotatably supported by the guide member and separated in a direction transverse to the longitudinal direction of the guide member, and one end of the one of the workpiece support devices is provided. A pair of feed screws passing through the tunnel,
A nut fixed to each of the pair of rest devices and screwed to the pair of feed screws, respectively, and the back side of the one workpiece support device on the table for independently rotating the feed screws. A machine tool comprising a pair of rest devices, each of which comprises an independently controllable drive motor coupled to the one end of the feed screw. 3. The machine tool according to claim 2, wherein a part of the guide member is inserted into the tunnel, and the guide member is fixed to one rest device located closer to the one work support device. A machine tool provided with a pair of rest devices, wherein a cover for covering the member can advance into the tunnel.