JP2006088264A - Grinder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a grinder, grinding while reducing the influence of abrasion of a grinding wheel. <P>SOLUTION: This grinder includes: a support rotatably supporting a cylinder A having a circumferential surface; the grinding wheel 3 for grinding the circumferential surface while the cylinder A is rotated; an electric motor 4 for driving the grinding wheel 3 in rotation; a moving means for moving the support 1 in the direction of intersecting the center line of rotation of the grinding wheel 3; a means for setting the peripheral speed ratio of the grinding wheel 3 to the cylinder A; and a control part for controlling the rotating speed of the grinding wheel 3 on the basis of the peripheral speed ratio set by the means, wherein the peripheral speed ratio of the grinding wheel 3 to the cylinder A during grinding is set to the uniform peripheral speed ratio. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a grinding apparatus for grinding a circumferential surface of an object to be ground having a circumferential surface.

  FIG. 7 is a schematic diagram showing a layout configuration of a conventional grinding apparatus. A grinding device that grinds cylindrical bodies such as an inner ring and an outer ring of a rolling bearing to a predetermined size is described in, for example, “Non-Patent Document 1”. The grinding apparatus of FIG. 7 includes a support body 101 that rotatably supports the cylindrical body 100, a first moving means 102 that moves (cuts and moves) the support body 101 in a radial direction of the cylindrical body 100, and A cylindrical grindstone 103 that grinds the circumferential surface of the cylindrical body 100 while rotating the cylindrical body 100, an electric motor 104 that rotationally drives the grindstone 103, and a first wheel that moves the grindstone 103 in the direction of the rotation center line. 2 movement means 105.

In the grinding process of the cylindrical body 100 by this grinding apparatus, the cylindrical body 100 is rotatably mounted on the support body 101, the grindstone 103 is rotated by the electric motor 104, and the grindstone 103 is moved by the second moving means 105. , The support body 101 is moved by the first moving means 102, the circumferential surface of the cylindrical body 100 is brought into contact with the grindstone 103, and the cylindrical body 100 is driven to rotate by the rotational force of the grindstone 103, The inner circumferential surface of the cylindrical body 100 is ground by the rotational speed difference between the cylindrical body 100 and the grinding wheel 103 (cylindrical body 1: grinding wheel 50) and supported by the first moving means 102 as the grinding time elapses. A small amount of the body 101 is moved to press the cylindrical body 100 against the grindstone 103.
Mechanical Engineering Handbook, revised 5th edition, pages 17-156 of the Japan Society of Mechanical Engineers

  However, in the grinding apparatus configured as described above, the grindstone wears with the lapse of the grinding time, and the wear amount of the grindstone varies depending on the size of the grindstone, the rotation speed of the grindstone, and the like. Since it is difficult to maintain the dimensional accuracy between them, the dimensional accuracy is maintained by setting the grinding time to be slightly longer than the optimum processing time.

  However, since the factors affecting the dimensional accuracy are not clear and the adjustment of the grinding time is based on experience, an improvement measure has been demanded.

  The present invention has been made in view of such circumstances, and a main object of the present invention is to provide a grinding apparatus capable of grinding while reducing the influence of abrasion of a grindstone.

  A grinding apparatus according to a first aspect of the present invention includes a support that rotatably supports a workpiece having a circumferential surface, a grindstone that grinds the circumferential surface while rotating the workpiece, and rotates the grindstone. In a grinding apparatus comprising an electric motor for driving and a moving means for moving the support or the grindstone in a direction intersecting with the rotation center line of the grindstone, a peripheral speed ratio between the grindstone and the workpiece is set. And a control unit for controlling the rotational speed of the grindstone based on the peripheral speed ratio set by the means.

  In the first invention, even when the grindstone is worn with the lapse of the grinding time, the number of revolutions of the grindstone is controlled based on the set peripheral speed ratio. The grinding load can be equalized, and the dimensional accuracy between the plurality of workpieces can be maintained with high accuracy.

  In the grinding apparatus according to a second aspect of the invention, the control unit calculates a rotational speed based on the peripheral speed ratio set by the means, and the rotational speed calculated by the means is supplied to the drive circuit of the electric motor. And means for outputting.

  In the second invention, at the time of grinding, a drive signal is output to the drive circuit of the electric motor based on the means for setting the peripheral speed ratio of the grindstone and the workpiece, and the rotational speed of the grindstone is corrected to a low speed. Therefore, the grinding load applied to the workpiece during grinding can be equalized, and the dimensional accuracy between the plurality of workpieces can be maintained with high accuracy.

  According to the first invention, the grinding load applied to the workpiece during grinding can be equalized, and the dimensional accuracy between the plurality of workpieces can be maintained with high accuracy.

  According to the second invention, the grinding load applied to the workpiece during grinding can be equalized, and the dimensional accuracy between the plurality of workpieces can be maintained with high accuracy.

Hereinafter, the present invention will be described in detail with reference to the drawings showing embodiments thereof. FIG. 1 is a schematic diagram showing a layout configuration of a grinding apparatus according to the present invention.
The grinding apparatus shown in the figure grinds the inner circumferential surface of an object to be ground (hereinafter referred to as a cylindrical body) composed of a cylindrical body A such as an inner ring and an outer ring of a rolling bearing, and supports the cylindrical body A in a rotatable manner. A support 1, a first electric motor 2 that moves the support 1 in the radial direction of the cylindrical body A via a ball screw mechanism (a cutting movement), and a column that is arranged concentrically with the cylindrical body A Shaped grindstone 3, a second electric motor 4 that rotationally drives the grindstone 3, a third electric motor 5 that moves the second electric motor 4 and the grindstone 3 in the direction of the rotation center line of the grindstone 3, A cylindrical dresser 6 for sharpening the grindstone, a fourth electric motor 7 for rotating the dresser 6, and a moving means for moving the dresser 6 and the fourth electric motor 7 in the radial direction of the grindstone 3. , Drive circuits for the first to fourth electric motors 2, 4, 5, and 7 And a control unit 8 for controlling, and a display unit 9 for displaying the cord conditions or the like input to the control unit 8.

  The support body 1 includes a cutting base 1a having a rotatable rotating member that holds the cylindrical body A. A rotating shaft is supported on the back side of the cutting base 1a so as to be able to rotate only. The output shaft 2a of the electric motor 2 is interlocked. A ball screw mechanism for converting the rotation of the rotation shaft into movement in the axial length direction is provided between the rotation shaft and the cutting table 1 a, and the cutting table 1 a is moved by driving the first electric motor 2. It is comprised so that it may move to the axial direction of a rotating shaft with a rotating member.

  The grindstone 3 has a columnar shape that is small enough to be inserted and disposed inside the cylindrical body A, and is attached to one end of a shaft 11 that is rotatably supported by the bearing member 10. The bearing member 10 and the electric motor 4 are supported by a gantry 12 that can move in the direction of the rotation center line of the grindstone 3, and the gantry 12 is moved by the third electric motor 5. A large-diameter transmission wheel 13 is fitted and fixed to the output shaft 4 a of the electric motor 4, and a small-diameter transmission wheel 14 having a size about 1/10 that of the transmission wheel 13 is fitted to the shaft body 11. The rotation of the output shaft 4a is increased about 10 times and is transmitted to the grindstone 3.

  Between the output shaft of the third electric motor 5 and the gantry 12, a ball screw mechanism for converting the rotation of the output shaft into movement in the axial length direction is provided, and by driving the third electric motor 5 The gantry 12 is configured to move together with the grindstone 3 and the second electric motor 4 in the direction of the rotation center line of the grindstone 3, in other words, to a grinding position and a non-grinding position.

  The dresser 6 and the fourth electric motor 7 are supported by a support member 15, and are configured to move the dresser 6 in a direction in which the dresser 6 contacts and separates from the grindstone 3 by moving the support member 15.

  Grinding of the cylindrical body A by the grinding apparatus configured as described above is performed by holding the cylindrical body A on a rotating member and driving the third electric motor 5 to grind the grinding wheel 3 (inside the cylindrical body A). , The second electric motor 4 is driven to rotate the grindstone 3, the first electric motor 2 is driven to move the cylindrical body A (rotating member) in a direction in contact with the grindstone 3, and the cylindrical body A is moved Contact with the grindstone 3. In this contacted state, the rotational force of the grindstone 3 is transmitted to the cylindrical body A and the rotating member, and the cylindrical body A and the rotating member are driven to rotate in the rotational direction of the grindstone 3. The inner circumferential surface of the cylindrical body A is ground by the rotational speed difference between the rotational speeds of the cylindrical body A and the rotating member and the rotational speed of the grindstone 3, and the first electric motor is developed as the grinding time elapses. The cutting movement speed of the cutting table 1a by the motor 2 is adjusted to a minute amount.

In rough grinding, grinding is performed in the following steps.
(1) Indexing → The grindstone is moved at a high speed by the third electric motor 5 to a position where the grindstone and the cylindrical body do not contact with each other reliably.
(2) Semi-rapid → Step where contact between the grindstone and the cylindrical body is expected (the grindstone is moved at a low speed by the third electric motor 5 so as not to damage the grindstone).
(3) Black skin → After detecting contact between the grindstone and the cylindrical body, grinding with a rough surface of the cylindrical body (the second electric motor 4 rotates the grindstone at low speed so as not to damage the grindstone) Grind at low speed.)
(4) Rough → Main grinding (The grinding wheel is rotated at high speed by the second electric motor 4 to grind at high speed.)
(5) Finishing → Finishing grinding (The second electric motor 4 rotates the grindstone at a low speed and grinds at a low speed.)
(6) Spark out → Grinding considering the return of elastic deformation of the shaft 11 of the grindstone.

FIG. 2 is a block diagram of the control unit.
In the control unit 8 using a microprocessor, the grindstone 3 and the set circumferential speed ratio Vs / Vw of the cylindrical body A that are set to be an appropriate peripheral speed ratio based on data obtained by experiments in advance, the grindstone 3 Rotational speed Ns (rpm) at the time of grinding, grindstone diameter Ds (mmφ) before grinding, inner diameter Dw (mmφ) of grinding inner diameter of cylindrical body A, set rotational speed Nw (rpm) of cylindrical body A, grinding wheel 3 and an input unit 16 for inputting various conditions such as the type of the cylindrical body A, a switch 17 for starting grinding for starting a grinding process in a set grinding process, and selecting whether or not to perform rotation speed control And a drive circuit 20, 40, 50, 70 for the first to fourth electric motors 2, 4, 5, 7 are connected to the output section. The various conditions input by the input unit 16 are displayed on the display unit 9. Further, the control unit 8 includes a first calculation unit that calculates the peripheral speed Vw (m / min) of the cylindrical body A, and a peripheral speed Vso (m / min) of the grindstone 3 based on the set peripheral speed ratio Vs / Vw. ), A third calculator that calculates the rotational speed Nso (rpm) of the grindstone 3 based on the peripheral speed Vso (m / min) calculated by the second calculator, And a means for outputting the rotation speed Nso (rpm) calculated by the third calculation unit to the drive circuits 20, 40, 50 and 70 of the electric motors 2, 4, 5, and 7. Further, the control unit 8 is set with an allowable rotation speed of the grindstone 3 as a basic menu of the grinding apparatus, and the grindstone 3 cannot be rotated beyond the allowable rotation speed.

The circumferential speed Vw (m / min) of the cylindrical body A is based on the set rotational speed Nw (rpm) of the cylindrical body and the grinding finish inner diameter Dw (mmφ) of the cylindrical body Vw = Nw × Dw × π
It is calculated by the following formula.
The peripheral speed Vs (m / min) of the grindstone 3 is based on the rotational speed Ns (rpm) of the grindstone 3 and the grindstone diameter Ds (mmφ) before grinding Vs = Ns × Ds × π
It is calculated by the following formula.
The set peripheral speed ratio of the grindstone 3 and the cylindrical body A is Vs / Vw.
It is calculated by the following formula.

  FIG. 3 is a graph showing the relationship between the peripheral speed ratio and the surface roughness (quality). In FIG. 3, the surface roughness is 1.8 or more at a circumferential speed ratio of 31 or less, and the surface roughness is 2.0 or more at a circumferential speed ratio of 38 or more. Since it is 1.73 or less and the quality is good, the range of the peripheral speed ratio 32 to 37 is set to be an appropriate peripheral speed ratio.

In the above configuration, when performing grinding work,
1. The grindstone 3 and the cylindrical body A are selected, and the diameter of the grindstone and the inner diameter of the cylindrical body A are measured.
2. Enter the conditions for the grinding wheel 3 and cylinder A.
3. Set the rotation speed of cylinder A.
4. The set peripheral speed ratio set based on the data obtained through the experiment is input, and the switch 18 for starting the control of the rotational speed is turned on.
5. Various conditions and the like input to the control unit 8 are displayed on the display unit 9, and the conditions and the like are confirmed by viewing the display unit 9.
6. Turn on the switch 17 for starting grinding.

FIG. 4 is a flowchart showing the operation content of the control unit 8 for controlling the rotational speed of the grindstone. After the power is turned on, the control unit 8 starts a control operation. The set rotational speed Nw (rpm) of the cylindrical body A and the grinding inner diameter Dw (mmφ) of the cylindrical body A are input to the input unit 16 by the operator, and various conditions such as the rotational speed are input from the input unit 16 to the control unit 8. (S1) and displayed on the display unit 9. A value in the range of 32 to 37 is input by the operator to the input unit 16 as a set peripheral speed ratio Vs / Vw, and this set peripheral speed ratio Vs / Vw is taken into the control unit 8 from the input unit 16 (S2) and displayed. Displayed in the section 9. It is determined whether or not the switch 18 for controlling the rotational speed is turned on (S3). If the switch 18 is turned on, the rotational speed Nw (rpm) of the cylindrical body A and the grinding finish inner diameter Dw of the cylindrical body A are determined. Based on (mmφ), the peripheral speed Vw (m / min) of the inner periphery of the cylindrical body A is Vw = Nw × Dw × π
Further, based on the set peripheral speed ratio Vs / Vw and the inner peripheral peripheral speed Vw taken in S2, the peripheral speed Vso of the grindstone 3 is calculated as Vso = Vw × (Vs / Vw)
The rotational speed Ns of the grindstone 3 is calculated as Vs / (Ds × π) based on the grindstone diameter Ds (mmφ) before grinding and the peripheral speed Vs of the grindstone 3.
Is calculated (S4). Next, it is determined whether or not the rotational speed Nso of the grindstone 3 is equal to or lower than the allowable rotational speed (S5). If the rotational speed Nso is not equal to or lower than the allowable rotational speed, it is indicated that the set peripheral speed ratio Vs / Vw needs to be input again. 9 (S6), the process returns to S2 and waits for input. When the rotation speed is equal to or lower than the allowable rotation speed in S5, the rotation speed Nso of the grindstone 3 is output to the drive circuit 40 of the second electric motor 4, and the rotation speed Nso of the second electric motor 4 and the grindstone 3 is adjusted (S7). End control. After this control is completed, the grinding start switch 17 is turned on, and grinding is started.

  FIG. 5 is a graph showing the relationship between the grinding force when the rotational speed is not controlled and the cutting speed at the grinding wheel diameter, and FIG. 6 is the relationship between the grinding force when the rotational speed is controlled and the cutting speed at the grinding wheel diameter. It is a graph which shows.

  FIG. 5 shows three types of grindstones 3 having a grindstone diameter (large) of 30.86 mmφ, a grindstone diameter (medium) of 28.98 mmφ, and a grindstone diameter (small) of 27.90 mmφ. The larger the grindstone diameter, the greater the grinding force. The smaller the grinding wheel diameter, the smaller the grinding force, and the greater the difference in grinding force due to the difference in grinding wheel diameter.

  In FIG. 6, three types of grindstones 3 having a grindstone diameter (large) of 30.86 mmφ, a grindstone diameter (medium) of 38.98 mmφ, and a grindstone diameter (small) of 27.90 mmφ are used, but based on the set peripheral speed ratio Vs / Vw. Since the rotation speed Nso of the grindstone 3 is controlled, the difference in grinding force due to the difference in grindstone diameter is small.

  As described above, by controlling the rotational speed Nso of the grindstone 3 based on the set peripheral speed ratio Vs / Vw, the surface roughness can be reduced and the quality can be improved.

  In the embodiment described above, the cylindrical body A is the object to be ground and the grindstone 3 is ground. However, the grindstone 3 for grinding the cylindrical body A is the object to be ground. The dresser 6 is used as a grindstone, and the peripheral speed ratio between the grindstone made up of the dresser 6 and the workpiece made up of the grindstone 3 for grinding a cylindrical body is set in the same manner as in the above-described embodiment. You may comprise so that the rotation speed of the grindstone which consists of dressers 6 based on ratio may be controlled similarly to the said embodiment.

  In the embodiment described above, the support 1 that supports the cylindrical body A is configured to move in a direction that intersects the rotation center line of the grindstone 3. However, the grindstone 3 is supported by the cylindrical body A. You may comprise so that it may move to the direction which cross | intersects the rotation center line of the grindstone 3 with respect to the support body 1 to perform.

It is a schematic diagram which shows the layout structure of the grinding apparatus which concerns on this invention. It is a block diagram of the control part of the grinding device concerning the present invention. It is a graph which shows the relationship between the peripheral speed ratio of the grinding apparatus which concerns on this invention, and surface roughness. It is a flowchart which shows the operation | movement content of the control part which controls the rotation speed of the grinding device which concerns on this invention. It is a graph which shows the relationship between the grinding force when not controlling the rotation speed of the grinding device which concerns on this invention, and the cutting speed in a grindstone diameter. It is a graph which shows the relationship between the grinding force at the time of controlling the rotation speed of the grinding device which concerns on this invention, and the cutting speed in a grindstone diameter. It is a schematic diagram which shows the layout structure of the conventional grinding apparatus.

Explanation of symbols

A Cylindrical body (object to be ground)
DESCRIPTION OF SYMBOLS 1 Support body 2 1st electric motor (moving means)
3 Grinding wheel 4 Second electric motor 8 Control unit

Claims (2)

A support that rotatably supports a workpiece having a circumferential surface, a grindstone that grinds the circumferential surface while rotating the workpiece, an electric motor that rotationally drives the grindstone, and the support Or, in a grinding apparatus comprising a moving means for moving the grindstone in a direction intersecting the rotation center line of the grindstone, means for setting a peripheral speed ratio of the grindstone and the workpiece to be ground, and the means set by the means And a control unit that controls the rotational speed of the grindstone based on a peripheral speed ratio. The control unit includes means for calculating a rotation speed based on a peripheral speed ratio set by the means, and means for outputting the rotation speed calculated by the means to a drive circuit of the electric motor. The grinding apparatus as described.

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