JP3764368B2 - Workrest device and control method thereof - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a work rest device that supports a processed portion of a workpiece when grinding an outer peripheral surface of a long workpiece such as an engine crankshaft, for example, and a control method thereof.
[0002]
[Prior art]
In general, when grinding the outer peripheral surface of a long workpiece such as a crankshaft with a grinding machine, the workpiece is rotated around its axis while being supported between a pair of headstocks at both ends. A grinding wheel is brought into contact with the predetermined processing portion, and the outer peripheral surface of the processing portion is ground. During this grinding process, the workpiece may bend due to grinding resistance of the grinding wheel, etc., causing a shift between the rotation center of the headstock and the axis of the workpiece processing part, which may lead to a decrease in grinding accuracy. is there. In order to prevent such problems, in a grinding machine that grinds the crankshaft, etc., the work is processed by contacting the shoe from the opposite side of the grinding wheel to the outer peripheral surface of the work part. It is equipped with a work rest device that supports the part.
[0003]
[Problems to be solved by the invention]
However, in this conventional work rest device, during the machining of the workpiece, the shoe is opposed to the grinding wheel at a constant pressure by a cylinder or the like facing the grinding wheel regardless of the grinding speed of the outer peripheral surface of the machining portion. It is designed to be pressed against the outer peripheral surface of the processed part. In this case, since the outer peripheral surface of the workpiece is continuously cut, the radial dimension of the processed portion continues to change as the grinding progresses. In addition, the shoe is pressing toward the center of rotation of the workpiece, but as described above, the outer peripheral surface of the workpiece continues to change. Does not match. For this reason, the workpiece may move eccentrically, and the shoe cannot follow this. Therefore, there is a problem that the support position of the shoe with respect to the outer peripheral surface of the processed portion of the workpiece does not immediately correspond to the grinding state of the outer peripheral surface of the processed portion, and high-precision grinding cannot be performed.
[0004]
The present invention has been made paying attention to such problems existing in the prior art. The purpose is a work rest device that can move the support position of the shoe with respect to the outer peripheral surface of the work part of the work in accordance with the grinding state of the outer peripheral surface of the work part and perform high-precision grinding. And providing a control method thereof.
[0005]
[Means for Solving the Problems]
In order to achieve the above object, the invention described in claim 1 is used when grinding the outer peripheral surface of a workpiece while rotating an elongated workpiece around its axis while supporting the workpiece at both ends. In the work rest device that supports the cylindrical part during grinding,
Control means is provided for controlling the movement of the support position of the shoe provided in the machining portion whose dimension in the radial direction of the workpiece changes in accordance with the rotation angle of the workpiece so as to follow the radial direction of the machining portion. The control means sets the radius dimension of the machining point during grinding to d, the machining point to the shoe in accordance with the displacement amount of the outer peripheral surface of the machining part according to the rotation angle of the workpiece from the workpiece machining point to the shoe support position . When the rotation angle to the support position is R and the cutting speed of the machining point is q, the distance D from the rotation center of the workpiece to the shoe support position is calculated based on the following equation (1) to support the shoe. The position is controlled to move.
D = d + (R / 2π) × q (1)
Here, q is represented by a cutting amount (mm / rev) per rotation of the workpiece, and this is called a cutting speed.
[0006]
Therefore, according to the first aspect of the present invention, during the grinding of the processed portion of the workpiece, the shoe support position relative to the outer peripheral surface of the processed portion is set to the ground state of the outer peripheral surface of the processed portion, that is, the amount of displacement. The setting can be changed as needed. Therefore, the support position of the shoe with respect to the outer peripheral surface of the processed portion of the workpiece can be made to immediately correspond to the cylindrical radius of the outer peripheral surface of the processed portion, and the workpiece can be ground with high accuracy. Further, the shoe support position from the rotation center of the workpiece can be easily calculated based on the equation (1).
[0007]
The invention according to claim 2 supports the cylindrical portion during grinding when the outer peripheral surface of the workpiece is ground while rotating around the axis while the long workpiece is supported at both ends. In the method for controlling the work rest device,
Control means is provided for controlling the movement of the support position of the shoe provided in the machining portion whose dimension in the radial direction of the workpiece changes in accordance with the rotation angle of the workpiece so as to follow the radial direction of the machining portion. When the radius of the machining point being ground is d, the rotation angle from the machining point to the shoe support position is R, and the cutting speed at the machining point is q, the control means is the shoe support position from the workpiece rotation center. Is calculated based on the following equation (1) to control the movement of the shoe support position .
[0008]
D = d + (R / 2π) × q (1)
Here, q is represented by a cutting amount (mm / rev) per rotation of the workpiece, and this is called a cutting speed.
[0009]
Therefore, according to the second aspect of the invention, the same action as that of the first aspect can be obtained.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
As shown in FIG. 1, in this grinding machine, a workpiece support device 12 is disposed on a base 11. That is, the moving table 13 is supported on the upper surface of the base 11 so as to be movable in the X direction via a pair of guide rails 14. A pair of headstocks 15 and 16 are supported on the upper surface of the moving table 13 so as to be movable in the X direction via the guide rails 17, and work pieces such as a crankshaft are supported at both ends at their opposite ends. Chucks 15a and 16a are provided.
[0015]
A grindstone device 18 is disposed on the base 11 so as to correspond to the workpiece support device 12. That is, a grindstone base 19 is supported on the upper surface of the base 11 through a pair of guide rails 20 so as to be movable in the Y direction, and a processing head 21 is disposed on the upper surface. A rotating shaft 22 is rotatably supported by the machining head 21, and a grinding wheel 23 is attached to the tip thereof.
[0016]
A grinding wheel rotating motor 24 is disposed on the grinding wheel base 19, and the grinding wheel 23 is rotated by the motor 24 via pulleys 25 and 26 and a belt 27. A grindstone moving motor 28 is disposed at the rear end of the base 11, and the grindstone table 19 is moved in the Y direction by a ball screw (not shown).
[0017]
When grinding the processing portions Wa to We such as journals in the workpiece W such as the crankshaft, the workpiece W is mounted between the pair of headstocks 15 and 16 for moving the table (not shown). The moving table 13 is moved in the X direction by the motor. By this movement, predetermined machining portions Wa to We of the workpiece W are arranged in correspondence with the grinding wheel 23. In this state, the workpiece W is rotated about the axis L by a workpiece rotating motor (not shown). At the same time, the grinding wheel 23 is moved toward the workpiece W by the grinding wheel moving motor 28 at a predetermined cutting speed in the Y direction while being rotated by the grinding wheel rotating motor 24 at a predetermined rotational speed. By this approaching movement, the grinding wheel 23 is brought into contact with predetermined machining portions Wa to We of the workpiece W, and the outer peripheral surfaces of the machining portions Wa to We are ground.
[0018]
As shown in FIGS. 1 and 2, a work rest device 29 is disposed on the base 11, and when predetermined processing portions Wa to We of the work W are ground, The processing portions Wa to We are supported so as to face the grinding wheel 23. That is, the first support arm 30 and the second support arm 31 are rotatably supported on the base 11 via the support shaft 32, and the tip ends of the first support arm 30 and the second support arm 31 are arranged on the outer peripheral surfaces of the processing portions Wa to We of the workpiece W. A first shoe 30a and a second shoe 31a that abut from the side and from below are provided.
[0019]
A spring 33 is hooked on the first support arm 30, and the spring 33 causes the first support arm 30 to move counterclockwise in FIG. 2, that is, the first shoe 30 a is separated from the processed portions Wa to We of the workpiece W. It is urged to rotate in the direction of movement. A spring 34 is hooked on the second support arm 31, and the spring 34 causes the second support arm 31 to move in the clockwise direction in FIG. 2, that is, in the direction in which the second shoe 31 a is separated from the processed portions Wa to We of the workpiece W. Is urged to rotate.
[0020]
A plunger 35 is brought into contact with the end portion of the first support arm 30, and a first servo motor 36 as a driving means is operatively connected to the plunger 35 via a ball screw (not shown). Then, the rotation of the first servo motor 36 rotates the first support arm 30 via the ball screw and the plunger 35, so that the first shoe 30 a has a predetermined support for the outer peripheral surfaces of the processed portions Wa to We of the workpiece W. It is arranged to move to the position.
[0021]
A plunger 37 is connected to the end of the second support arm 31, and a second servo motor 38 as a driving means is operatively connected to the plunger 37 via a ball screw (not shown). Then, the second support motor 31 is rotated by the rotation of the second servo motor 38 via the ball screw and the plunger 37, so that the second shoe 31a supports the outer peripheral surface of the processed portions Wa to We of the workpiece W with a predetermined support. It is arranged to move to the position.
[0022]
Next, the circuit configuration of the work rest device 29 configured as described above will be described. As shown in FIG. 3, a control device 41 as control means is connected to a memory 42 as storage means, an input device 43 such as a keyboard, and both the servo motors 36 and 38. Then, in the memory 42, as shown in FIG. 4, the rotation angle from the machining point P0 to the machining portions Wa to We of the workpiece W to the support positions P1 and P2 of the shoes 30a and 31a is obtained by the input from the input device 43. The displacement amounts o1 and o2 of the outer peripheral surfaces of the corresponding processed portions Wa to We are stored in advance.
[0023]
That is, as shown in FIGS. 4 and 5, when grinding the processed portions Wa to We of the workpiece W, the outer peripheral surface of the processed portions Wa to We extends from the processing point P0 to the support positions P1 and P2 of the shoes 30a and 31a. By being rotated, a displacement of a cutting amount corresponding to the rotation angle is generated. In this case, when the rotation angle from the processing point P0 to the support positions P1, P2 of the shoes 30a, 31a is R1, R2 (degrees) and the cutting speed of the processing point P0 is q (mm / rev), each shoe The displacements o1 and o2 (mm) at the support positions P1 and P2 of 30a and 31a are expressed by the following equations (2) and (3). The displacements o1 and o2 are stored in the memory together with the movement control position data of the grindstone base 19. 42.
[0024]
o1 = (R1 / 2π) × q (2)
o2 = (R2 / 2π) × q (3)
The control device 41 changes the support positions P1 and P2 of the shoes 30a and 31a based on the displacement amounts o1 and o2 stored in the memory 42 during the grinding of the processed portions Wa to We of the workpiece W. Control. That is, as shown in FIG. 4, when the radius dimension of the processing point P0 during grinding is d, the distance from the rotation center La on the rotation axis L of the workpiece W to the support positions P1, P2 of the shoes 30a, 31a. D1 and D2 (mm) are calculated based on the following equations (4) and (5).
[0025]
D1 = d + o1 = d + (R1 / 2π) × q (4)
D2 = d + o2 = d + (R2 / 2π) × q (5)
And the control apparatus 41 drives the 1st servo motor 36 and the 2nd servo motor 38 based on the position data by the movement control of the grindstone base 19, and the calculated value of these distances D1 and D2, and each shoe 30a. , 31a is changed and controlled. For this reason, each shoe 30a, 31a can change the support position with respect to the process parts Wa-We according to the displacement accompanying the grinding process of the process parts Wa-We of the workpiece | work W. FIG.
[0026]
Therefore, according to this embodiment, the following effects can be obtained.
(A) The work rest device 29 is provided with a pair of shoes 30a and 31a that support the processed portions Wa to We of the workpiece W during grinding of the outer peripheral surface of the workpiece W. Then, the control unit 41, each shoe 30a with respect to the outer peripheral surface of the working portion Wa～We, the support positions P1, P2 of the 31a, the rotation of the machining point P0 of the workpiece W to the support positions P1, P2 of the shoes 30a, 31a Based on the displacements o1 and o2 of the outer peripheral surfaces of the machining portions Wa to We according to the angle , change control is performed in the radial direction of the machining portions Wa to We.
[0027]
For this reason, during grinding of the processed portions Wa to We of the workpiece W, the support positions P1 and P2 of the shoes 30a and 31a with respect to the outer peripheral surfaces of the processed portions Wa to We are ground on the outer peripheral surfaces of the processed portions Wa to We. The setting can be changed at any time according to the state. Therefore, the workpiece W can be ground with high accuracy.
[0028]
(B) In this work rest device 29, the radius dimension of the machining point P0 being ground is d, the rotation angles from the machining point P0 to the support positions P1, P2 of the shoes 30a, 31a are R1, R2, and the machining point P0. The distance D1, D2 from the rotation center La on the rotation axis L of the workpiece W to the support positions P1, P2 of the shoes 30a, 31a is represented by the following equations (4) and (5) It is calculated on the basis of
[0029]
D1 = d + (R1 / 2π) × q (4)
D2 = d + (R2 / 2π) × q (5)
For this reason, the support positions P1, P2 of the shoes 30a, 31a from the rotation center La of the workpiece W can be easily calculated based on the equations (4) and (5).
[0030]
(C) The work rest device 29 is provided with a memory 42 for storing displacement amounts o1 and o2 of the outer peripheral surfaces of the machining portions Wa to We corresponding to the rotation angles of the shoes 30a and 31a. Then, the support positions P1 and P2 of the shoes 30a and 31a are changed and controlled based on the displacement amounts o1 and o2 stored in advance in the memory 42 together with the position data obtained by the movement control of the grinding wheel head 19 by the control device 41. It has become. Therefore, the support positions P1, P2 of the shoes 30a, 31a can be easily changed and controlled based on the displacement amounts o1, o2 stored in the memory 42.
[0031]
(D) In the work rest device 29, servo motors 36 and 38 are used as drive means for changing the support positions P1 and P2 of the shoes 30a and 31a. For this reason, it is possible to accurately change and control the support positions P1 and P2 of the shoes 30a and 31a by driving the servomotors 36 and 38.
[0032]
(Example of change)
In addition, this embodiment can also be changed and embodied as follows.
In the above embodiment, the crankshaft is a workpiece, but other than that, for example, a camshaft is a workpiece.
[0033]
In the above embodiment, the processed portion is the journal of the crankshaft, but the processed portion is a crank pin.
In the embodiment, the first support arm 30 and the second support arm 31 are rotatably arranged corresponding to the processed portions Wa to We of the workpiece W, and the end portions of the support arms 30 and 31 are arranged. A first shoe 30a and a second shoe 31a were provided. On the other hand, the first shoe 30a and the second shoe 31a are arranged so as to be opposed to the outer peripheral surfaces of the processed portions Wa to We of the workpiece W so as to be linearly movable in the radial direction, and the first servo motor 36 is arranged. The second servo motor 38 is configured to be moved via a ball screw. If comprised in this way, since the shoes 30a and 31a can be displaced to the radial direction centering on the center of the workpiece | work W, the force to an eccentric direction does not act with respect to the workpiece | work W, and processing precision is improved. It can be further improved.
[0034]
In the embodiment, the outer peripheral surfaces of the processed portions Wa to We of the workpiece W are supported by the two shoes 30a and 31a, but are supported so as to hold the workpiece by two or more shoes. To be configured. Even in the case of such a configuration, the effect can be obtained by substantially the same means as in the above embodiment.
[0035]
【The invention's effect】
As described above in the embodiment, in the present invention, the shoe support position with respect to the outer peripheral surface of the processed portion of the workpiece can be set and changed according to the grinding state of the outer peripheral surface of the processed portion. The effect of being able to perform the grinding process is exhibited.
[Brief description of the drawings]
FIG. 1 is a plan view showing a grinding machine equipped with a work rest device according to an embodiment.
FIG. 2 is an enlarged side view showing the work rest device of FIG. 1;
FIG. 3 is a block diagram showing a circuit configuration of the work rest device.
FIG. 4 is an explanatory diagram for explaining the operation of the work rest device.
FIG. 5 is a graph showing a relationship between a rotation angle of a workpiece and a cutting amount.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 11 ... Base, 12 ... Work support apparatus, 13 ... Moving table, 15, 16 ... Spindle base, 18 ... Grinding wheel apparatus, 19 ... Grinding wheel base, 21 ... Processing head, 23 ... Grinding wheel, 29 ... Work rest apparatus, 30 ... 1st support arm, 30a ... 1st shoe, 31 ... 2nd support arm, 31a ... 2nd shoe, 36 ... 1st servomotor as drive means, 38 ... 2nd servomotor as drive means, 41 ... control Control device as means, 42 ... Memory as storage means, W ... Work, Wa ... Machining part, L ... Rotating axis, P0 ... Machining point, P1, P2 ... Support position, D1, D2 ... Distance, R1, R2 ... Rotation angle , o1, o2,.

Claims (2)

In the work rest device that supports the cylindrical part during grinding when grinding the outer peripheral surface of the work while rotating around the axis while supporting the long work at both ends,
A control means is provided for moving and controlling the shoe support position provided in the machining portion where the radial dimension of the workpiece changes in accordance with the rotation angle of the workpiece so as to follow the radial direction of the machining portion,
The control means sets the radius dimension of the machining point during grinding to d, the machining point to the shoe in accordance with the displacement amount of the outer peripheral surface of the machining part according to the rotation angle of the workpiece from the workpiece machining point to the shoe support position. When the rotation angle to the support position is R and the cutting speed at the machining point is q, the distance D from the center of rotation of the workpiece to the support position of the shoe is calculated based on the following equation (1) and features and to Ruwa over crest device to control the movement of the support position.
D = d + (R / 2π) × q (1) In the control method of the work rest device that supports the cylindrical portion during grinding, when rotating the outer peripheral surface of the workpiece while rotating the axis around the axis while supporting the long workpiece at both ends,
A control means is provided for controlling the movement of the support position of the shoe provided in the machining portion whose dimension in the radial direction of the workpiece changes according to the rotation angle of the workpiece so as to follow the radial direction of the machining portion, When the radius of the machining point being ground is d, the rotation angle from the machining point to the shoe support position is R, and the cutting speed of the machining point is q, the control means is the shoe support position from the workpiece rotation center. A control method for a work rest device, wherein the distance D is calculated based on the following equation (1) to control the movement of the shoe support position.
D = d + (R / 2π) × q (1)

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