JPH04125554U - Lathe - Google Patents

Abstract

(57) [Summary] [Purpose] To reduce the error in the origin position due to thermal displacement of the machine body and improve machining accuracy. [Structure] A detection arm 14 with a low coefficient of thermal expansion whose tip becomes a detected portion 15 is provided on a turret carriage 3 that mounts a turret 2 and moves in the X-axis direction, extending toward the headstock 7 side.
An origin detection switch 13 for detecting this detected portion 15 is provided near the headstock 7. In this way, by shortening the distance from the headstock 7 to the origin detection switch 13, the bed 4
Reduce the deviation in the setting position of the mechanical origin Q _XO due to thermal displacement.

Description

[Detailed explanation of the idea]

0001

[Industrial application field]

This idea places a turret carriage equipped with a turret on the bed rail. This invention relates to a lathe that is installed so that it can be fed in a direction near and far from a headstock.

0002

[Conventional technology]

Conventionally, in a turret lathe, the mechanical origin Q _XO of the turret 33 in the X-axis direction is set away from the main shaft 31, as shown in FIG. The reason why the machine origin Q _XO is set at a position away from the main shaft 31 in this way is, for example, as follows. In other words, tool indexing by rotating the turret 31 is performed when the machine returns to the machine origin _Q be.

[0003] The return of the turret 33 to the machine origin _Q This is done by turning on 32 with dog 35. In response to the ON signal of the limit switch 32, the mechanical origin Q _XO is made to coincide with the origin of the absolute coordinates of the numerical control in the NC device.

0004

[Problem that the idea aims to solve]

However, since the machine origin _Q , the amount by which the position of the machine origin Q _XO deviates from the axis Q ₁ of the main shaft 31 increases. Therefore, there is a problem that processing errors become large.

[0005]This problem will be explained in detail. During machining, by determining the tool 38 to be used, the cutting edge position data, which is the distance Xt in the X-axis direction from the axis Q ₂ of the turret 33 to the cutting edge of the tool 38, is input to the NC device. The position can be determined. Thereafter, by moving the turret 33 in the X-axis direction by rotation of the feed screw 37, the tool 38 is brought closer to the machining position and machining is performed. The position of the cutting edge of the tool 38 at that time is calculated by the NC device by counting the number of pulses generated from a pulse generator 36a provided in the X-axis servo motor 36.

Now, if the moving distance in the X-axis direction per pulse is ΔX ₁ , then the cutting edge position Q of the tool 38 when counting the number of pulses m from the machine origin Q _x0 is on the absolute coordinates, Q= Xt+m・ΔX ₁ .... However, when the bed 30 expands due to a rise in temperature, the distance Xs from the axis _Q1 of the spindle 31 to the limit switch 32 increases to Xs+ΔXs, and as shown in _FIG . It is further away from the axis _Q1 of the main shaft 31 by ΔXs than the mechanical origin _Qx0 before the lift.

In other words, if the distance from the axis Q ₂ of the turret 33 to the limit switch 32 is L ₁ and temperature changes in this distance are ignored, then the distance from the axis Q ₁ of the main shaft 31 to the machine origin Q _x0 is: While it is Xs-L ₁ before the temperature rise, it becomes Xs+ΔXs-L ₁ after the temperature rise. As a result, compared to the cutting edge position Q of the tool 38 when counting the number m of pulses from the machine origin Q _x0 before the temperature rise, the cutting edge position Q' when counting the same number m of pulses after the temperature rise is The distance is ΔXs from the axis Q ₁ of 31. As mentioned above, the mechanical origin Q _x0 is set far from the axis Q ₁ of the main shaft 31, so the distance Xs becomes a considerably large value, and the error ΔXs due to thermal displacement also increases in proportion to this distance Xs. Become. Therefore, in the conventional example described above, the machining accuracy is greatly reduced due to thermal displacement of the machine body.

[0008] The purpose of this invention is to provide a lathe that can perform machining with high precision regardless of thermal displacement of the aircraft body. It is to provide.

[0009]

[Means to solve the problem]

The configuration of this invention will be explained with reference to FIG. 1 which corresponds to an embodiment. This idea moves the turret carriage (3) equipped with the turret (2) to the bed. It is possible to feed in the far direction (X-axis direction) with respect to the headstock (7) on the rail (5) of (4). In a lathe (1) installed in a Extend the detection arm (14) to the turret carriage (3) toward the headstock (7). An origin detection switch (13) for detecting the detected portion (15) is provided on the main shaft. It is installed near the stand (7).

0010

[Effect]

The origin (Q _x0 ) in the far and near directions with respect to the headstock (7) is the axis center (Q This is the position of Q ₂ ). Therefore, the _distance from the origin ( _Q This is the sum of the distance (L) to the detected part (15). Since the origin detection switch (13) is provided near the headstock (7), the distance (Xs) is sufficiently short, and the error in the distance (Xs) caused by thermal displacement of the bed (4) is small. On the other hand, since the detected portion (15) also consists of the tip of the detection arm (14) with a low coefficient of thermal expansion extending from the turret carriage (3), the error in distance (L) due to thermal displacement is also small. Therefore, the error caused by the influence of thermal displacement of the machine body regarding the distance from the headstock (7) to the origin (Q _x0 ) is reduced, and the machining accuracy is improved accordingly.

[0011]

【Example】

An embodiment of this invention will be described based on FIGS. 1 to 4. In Fig. 1, lathe 1 consists of a turret lathe, and is equipped with a turret 2. The carriage 3 is placed on the rail 5 of the bed 4 perpendicular to the axial direction (Z-axis direction) of the main shaft 6. It is installed so that it can be moved freely in the direction of the X-axis (X-axis direction). Main shaft 6 is installed on bed 4 The spindle chuck 6a is mounted on a spindle chuck 6a.

0012 The turret carriage 3 is installed on the rail 8 and is movable in the Z-axis direction. It has an index housing 9, and a turret shaft is attached to this index housing 9. The turret 2 is rotatably supported via the turret 2a. index housing 9 incorporates an indexing rotation mechanism and a forward/backward feeding mechanism for the turret 2. Taret The carriage 3 is moved in the X-axis direction by an X-axis servo motor 11 via a feed screw 10. This is done by The turret 2 is drum-shaped with a polygonal front shape, and each Various tools 12 are mounted on a tool station consisting of a peripheral surface.

The machine origin Q _x0 in the X-axis direction is located at a position near the headstock 7 at the rear of the bed ₄ , that is, at a position away from the axis Q1 of the spindle 6 by a distance Xs toward the turret carriage 3 in the X-axis direction. An origin detection switch 13 is provided for detecting. Further, the turret carriage 3 is provided with a detection arm 14 extending toward the headstock 7 from a position corresponding to the axis Q ₂ of the turret 2. The detection arm 14 is made of a material with a low coefficient of thermal expansion, such as ceramic or an alloy with a low coefficient of thermal expansion. A dog 15, which is a detected portion detected by the origin detection switch 13, is formed at the tip of the detection arm 14. That is, this dog 15 is formed at a position where it contacts the origin detection switch 13 and turns on the origin detection switch 13 when the axis Q ₂ of the turret 2 coincides with the machine origin Q _x0 in the X-axis direction. .

[0014] The headstock 7 detects when the turret 2 approaches the spindle 6 side as shown in Figure 2. An arm escape hole 7a is formed through the arm 14 to avoid collision with the arm 14.

[0015] In FIG. 1, a control device 16 is a device that controls the entire lathe 1, and is a device that controls the entire lathe 1. It consists of a marble controller and an NC device, and analyzes and executes 17 machining programs. The arithmetic control unit 18 drives the X-axis servo motor 11 and the other axis servo motors 19. Equipped with 20 servo drivers.

[0016] The operation of the above configuration will be explained. As shown in FIG. 3, when starting workpiece machining, first the calculation control section of the control device 16 An operation is performed to match the origin of the absolute coordinates set in step 18 with the machine origin ( S1). This operation in the X-axis direction will be explained as follows.

The turret carriage 3 is moved in the X-axis direction until the dog 15 at the tip of the detection arm 14 contacts the origin detection switch 13 and the origin detection switch 13 is turned on. As the turret carriage 3 moves in the X-axis direction, the calculation control unit 18 of the control device 16 counts the number of pulses of the pulse generator 11a of the X-axis servo motor 11. When the origin detection switch 13 is on, the axis Q ₂ of the turret 2 coincides with the mechanical origin Q _x0 in the X-axis direction. The ON signal of the origin detection switch 13 is input to the arithmetic control section 18, and at this point the arithmetic control section 18 resets the count pulse number of the pulse generator 11a to zero. As a result, the zero point on the X-axis in absolute coordinates coincides with the mechanical origin Q _x0 .

Next, the tool 12 to be used is determined by rotating the turret 2, and the cutting edge position data of the tool 12 is input to the calculation control unit 18 (S2). When inputting the cutting edge position data, for example, in the case of data regarding the X axis, the distance Xt from the determined cutting edge position of the tool 12 to the axis Q ₂ of the turret 2 is input to the calculation control unit 18 . As a result, when the axis Q ₂ of the turret 2 coincides with the machine origin Q _x0 , the position of the cutting edge on the X axis in absolute coordinates is determined to be the position Xt from the origin.

Next, an operation is performed to move the cutting edge of the tool 11 to the processing position of the workpiece W (S3). This operation is as follows in terms of movement in the X-axis direction. When the tool 11 is fed using the X coordinate value specified by the machining program 17 as the target value as the machining position, the servo driver 20 counts the number of pulses of the pulse generator 11a of the X-axis servo motor 11. If the amount of movement in the X-axis direction per pulse is ΔX, then the cutting edge position Q of the tool 11 in absolute coordinates when counting the number of pulses m from the machine origin Q _x0 is as follows: Q=Xt+m·ΔX...

[0020] The machining operation is executed while moving until this calculated position matches the target machining position. is executed (S4). The above operations are repeated until the machining is completed (S5).

By the way, in the above home alignment, suppose that the distance Xs between the headstock 7 and the home position detection switch 13 increases by ΔXs due to a rise in temperature, and the thermal expansion of the detection arm 14 made of a material with a low coefficient of thermal expansion is ignored. Considering this, the distance from the spindle 6 to the machine origin Q _x0 has also increased by ΔXs. Therefore, as shown in FIG. 4, origin alignment is performed by setting the mechanical origin Q' _x0 at a position shifted by ΔXs from the mechanical origin Q _x0 before the temperature rise. Therefore, when the number of count pulses of the pulse generator 11a of the X-axis servo motor 11 is, for example, m, the distance of the cutting edge position Q' of the tool 12 from the axis _Q1 of the main shaft 6 is also equal to the number of count pulses m before the temperature rise. It becomes further by ΔXs than the distance to the cutting edge position Q at that time.

However, in this lathe, since the distance Xs from the axis Q ₁ of the main spindle 6 to the origin detection switch 13 is short, the error ΔXs is correspondingly small, making it possible to minimize the reduction in machining accuracy caused by thermal displacement. can. In addition, the dog 15 that contacts the origin detection switch 13 to turn it on is formed at the tip of the detection arm 14 extending from the turret carriage 3 toward the headstock 7. Even though the detection switch 13 is in the position, the mechanical origin _Qx0 for the X-axis can be set sufficiently far from the axis _Q1 of the main spindle 6.

[0023]

[Effect of the idea]

The lathe of this invention can be fed in the far and near directions relative to the headstock on the rails of the bed. The installed turret carriage has a low coefficient of thermal expansion, with the tip being the detected part. The output arm is extended toward the headstock side, and an origin point for detecting the detected portion is provided. Since the detection switch is installed near the headstock, the origin position cannot be changed due to thermal displacement of the machine body. This has the effect of reducing errors and allowing highly accurate machining.

[Brief explanation of drawings]

FIG. 1 is a conceptual diagram showing the configuration of an embodiment of this invention.

FIG. 2 is a perspective view showing main parts in the same embodiment.

FIG. 3 is a flowchart showing the processing operation.

FIG. 4 is an explanatory diagram showing errors in the position of the cutting edge due to thermal displacement of the machine body in the lathe.

FIG. 5 is a conceptual diagram showing the configuration of a conventional lathe.

FIG. 6 is an explanatory diagram showing an error in the position of the cutting edge due to thermal displacement of the machine body in the lathe.

[Explanation of symbols]

2...turret, 3...turret carriage, 4...bed,
5...Rail, 6...Spindle, 7...Spindle stock, 7a...Arm escape hole, 11...X-axis servo motor, 11a...Pulse generator, 12...Tool, 13...Origin detection switch, 14...Detection arm, 15...Dog ( Detected part), 16 control device, 18...computation control unit, Q _x0 ...mechanical origin

Claims (1)

[Scope of utility model registration request] Claim 1: In a lathe in which a turret carriage carrying a turret is installed on a rail of a bed so as to be able to be moved in a direction near and far from a headstock, a detection arm with a low coefficient of thermal expansion whose tip is a detected part is attached to the turret. The lathe is provided with an origin detection switch extending toward the headstock side on the spindle carriage and near the headstock for detecting the detected portion.