JPH06344252A - Centerless grinding method and apparatus for stepped work - Google Patents

Abstract

PURPOSE:To keep the stable attitude and peripheral speed of a work so as to obtain high circularity and cylindricity in an infeed centerless grinding for a stepped work. CONSTITUTION:In the case of rough grinding with large grinding resistance, a stepped work W by a regulating wheel R and a shoe S to grind the small- diameter part (a) and the large-diameter part (b) in the same manner, and when the grinding draws to an end to perform finish-grinding with small grinding resistance, the state of supporting the work W by the shoe S is released and while the work W is supported only by the regulating wheel R, the work is ground. Thus, both diameter parts (a) (b) of the work W are corrected and finish-ground by grinding wheel surfaces Ga, Gb of a correctly formed grinding wheel G without any influence of the relative positional relationship between the regulating wheel R and the shoe S to obtain good circularity and cylindricity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for centerless grinding of stepped workpieces, and more particularly to a technique for centerless grinding of workpieces having cylindrical shaft portions having different outer diameters by infeed.

[0002]

2. Description of the Related Art When a so-called stepped workpiece (hereinafter referred to as a work) having two cylindrical shaft portions having different outer diameters is subjected to center feed grinding by in-feed, a work W as shown in FIG. The small diameter part of the work W is supported by the grinding wheel G which also has the profile corresponding to the cylindrical outer diameter surface of the work W while being supported by the adjusting wheel R and the receiving plate (blade) B having the profile matching the outer diameter surface of the cylinder. Grind a and large diameter b.

In this case, the small diameter portion a and the large diameter portion b of the work W are
However, since there is a difference in outer diameter, a difference (peripheral speed difference) occurs in the peripheral speeds of the two radial portions a and b, and the Ra or Rb portion of the adjusting vehicle R that is in contact with both the radial portions a and b respectively. There is always relative slippage in either one.

That is, the peripheral speed of the small diameter portion a is R of the adjusting wheel R.
When the peripheral speed of the portion a matches, the relative slippage occurs between the large diameter portion b and the Rb portion of the adjusting vehicle R, while the peripheral speed of the large diameter portion b becomes equal to the peripheral speed of the Rb portion of the adjusting vehicle R. When they match, a relative slip occurs between the small-diameter portion a and the Ra portion of the adjusting vehicle R. As a result, the adjusted vehicle R in which this relative slip has occurred
The portion Ra or Rb is worn earlier than the other portion Rb or Ra, and there is a problem that the grinding accuracy (roundness, cylindricity, etc.) of the work W is reduced.

In relation to this point, various centerless grinding techniques have been conventionally developed and proposed. For example, Japanese Patent Publication Sho 60-
No. 44108 discloses a structure in which the Ra portion and the Rb portion of the adjusting vehicle R are independent from each other, and one of them, for example, the Rb portion, is fixed to the adjusting vehicle drive shaft Rs. And the other Ra portion is supported so as to be freely rotatable with respect to the adjustment vehicle drive shaft Rs.

At the time of grinding, R of the adjusting wheel R is
The work W is braked and rotated by the portion b, and the Ra portion simply supports the small-diameter portion a of the work W for free rotation, thereby preventing relative slip between the work W and the adjusting vehicle R. In addition, when dressing the adjusting wheel R, it is necessary to accurately form the steps corresponding to both the diameter portions a and b of the work W, so that the connecting pin R (not shown)
The a part and the Rb part are integrally joined to perform dressing.

Further, in the one disclosed in Japanese Patent Application Laid-Open No. 4-93161, the Ra portion and the R portion of the adjusting vehicle R are attached to the respective independent drive mechanisms so that the Ra portion and the R portion can be separated from each other.
The number of rotations (rotational speed) of the portion b is independently controlled to prevent relative slip between the work W and the adjusting vehicle R.

Further, as shown in FIG. 6, one of the workpieces W, for example, the large-diameter portion b is braked and supported by the adjusting wheel R,
On the other hand, for example, there is one in which the small diameter portion a is supported by the shoe S. In this structure, after the positional relationship between the adjusting vehicle R and the shoe S and the work W is determined, the work W and the adjusting vehicle R are sent by integrally feeding them.
I try not to cause relative slip between and.

[0009]

However, all of these conventional grinding techniques have the following problems.

(1) In the one disclosed in Japanese Examined Patent Publication No. 60-44108, it is necessary to integrally combine the Ra portion and the Rb portion of the adjusting wheel R in order to obtain an accurate profile when dressing the adjusting wheel R. However, the connecting work and the detaching work must be performed with the rotation of the adjusting vehicle R temporarily stopped, and the workability is extremely poor.

(2) In the one disclosed in Japanese Patent Laid-Open No. 4-93161, since the Ra part of the adjusting vehicle R and the drive mechanism of Rb are independent, the device itself becomes large and the device cost is high. Cause rise.

(3) In the structure shown in FIG. 6, the adjusting vehicle R
Since the shoe S and the shoe S are fed at the same time, the small diameter portion a and the large diameter b of the work W are ground in the same manner, and the grinding accuracy is deteriorated. In other words, adjusting car R and shoe S
Of the workpiece W changes due to the difference in wear between the two, and as a result, the roundness and cylindricity of the work W deteriorate. For example, when the adjusting car R approaches the work W side from the desired setting position, the work W causes a tilted state as shown in FIG. 7 (a), while the adjusting car R moves from the desired setting position to the work W side. When the work W is separated from the work W, the work W causes a tilted state as shown in FIG. 7B, and in any case, accurate roundness and cylindricity cannot be obtained.

Further, it is very difficult to adjust the relative positional relationship between the adjusting wheel R and the shoe S, and even if the relative position can be adjusted to a desired set value by some adjusting method, the shoe S can be adjusted. Since the adjustment vehicle R wears faster than in Fig. 7, the work W also has the same tilted state as in Fig. 7 (b).

The present invention has been made in view of such conventional problems, and an object of the present invention is to maintain a stable posture and peripheral speed of a stepped work while maintaining a high roundness and cylindricity. It is to provide a centerless grinding method and apparatus capable of obtaining the following.

[0015]

In order to achieve the above object, the grinding method of the present invention is a method of centerless grinding the cylindrical outer diameter surface of a stepped work by in-feed, wherein one diameter part of the work is The adjusting wheel supports braking and rotation, and the other diameter part is supported by the shoe.In rough grinding, the adjusting wheel and the shoe are fed at the same speed, and in finishing grinding, the adjusting wheel is more than the shoe. It is characterized in that it is relatively advanced and fed.

During finish grinding, the feeding of the shoe is stopped and the adjusting wheel is fed, or the adjusting wheel and the shoe are fed, and the feeding speed of the adjusting wheel is determined from the feeding speed of the shoe. Try to be faster too.

Further, the grinding apparatus of the present invention is for carrying out the above-mentioned centerless grinding method, and has a grindstone surface formed to accurately make a step on the cylindrical outer diameter surface of the work, and is rotationally driven. A grinding wheel, an adjusting wheel for braking and rotating one diameter part of the work, a shoe for supporting the other diameter part of the work, a lower slide device for feeding the shoe, and a lower slide device provided on the lower slide device. An upper slide device for feeding the adjusting vehicle and a control device for automatically controlling the upper and lower slide devices in conjunction with each other are provided.

[0018]

According to the present invention, one diameter portion, for example, the large diameter portion of the stepped work supported on the blade is supported by the adjusting wheel for braking and rotation, and the other diameter portion, for example, the small diameter portion, is supported by the shoe, and the coarse workpiece is supported. At the time of grinding, the adjusting wheel and the shoe are fed at the same speed, that is, while the relative positional relationship between them is kept constant, and grinding is performed by a grinding wheel. On the other hand, in the subsequent finishing grinding, the adjusting wheel is moved forward relative to the shoe and fed in to perform grinding by the grinding wheel.

That is, during rough grinding with a large grinding resistance, the work is prevented from escaping by the shoe support, and the large diameter portion and the small diameter portion of the workpiece are ground in the same manner. On the other hand, at the time of finish grinding where the grinding resistance is close to the end and the grinding resistance is small, the support wheel is released from the shoe by advancing the adjusting wheel slightly ahead of the shoe, and only the adjusting wheel on the braking side is released. Grind while supporting the work. As a result, the work is not affected by the relative positional relationship between the adjusting wheel and the shoe with respect to the work, and both diameter portions are corrected and finish grinding is performed.

[0020]

Embodiments of the present invention will be described below with reference to the drawings.

Example 1 A centerless grinding machine according to the present invention is shown in FIGS. 1 to 3, and specifically, this grinding machine has a so-called stepped structure having two cylindrical shaft portions a and b having different outer diameters. For centerless grinding of the work W by in-feed, a grinding wheel G that is driven to rotate, an adjusting wheel R that supports the large diameter part b of the work W, a shoe S that supports the small diameter part a of the work W, a lower slide The device 1, the upper slide device 2, and the control device 3 are mainly configured. Reference numeral B denotes a blade (supporting plate) that supports the work W from below, and has a supporting surface Ba having a profile corresponding to the cylindrical outer diameter surface of the work W. Reference numeral 4 denotes a support base for supporting this blade, which is provided on the lower slide device 1.

As shown in the drawing, the grinding wheel G has a profile corresponding to the cylindrical outer diameter surface of the work W, that is, the grinding wheel surfaces Ga and Gb formed to accurately form a step on the cylindrical outer diameter surface.
have. The rotating spindle 10 of the grinding wheel G has a conventionally well-known general basic structure, is rotatably mounted on a grinding wheel stand 12 provided on an apparatus bed 11, and is a drive source such as a drive motor (not shown). Is associated with.

The adjusting wheel R supports a large-diameter portion b of the work W by braking and rotation, and its rotating main shaft 20 is rotatably mounted on the upper slide base 2a of the upper slide device 2 and a drive not shown. It is linked to a drive source such as a motor.

The shoe S supports the small diameter portion a of the work W, is attached to the blade B, and is mounted on the lower slide base 1a of the lower slide device 1.

The lower slide device 1 feeds the shoe S, and comprises a lower slide base 1a and a feed screw device 1b. The lower slide base 1a is reciprocally movable in the feeding direction X along a slide rail 13 provided on the apparatus bed 11, and the blade B and the shoe S are mounted on the upper surface of the lower slide base 1a and the upper slide apparatus 1a. 2 is movably mounted.

Further, the feed screw device 1b moves the lower slide base 1a, and comprises a ball screw 15a linked to the lower slide base 1a so as to be able to advance and retreat, and a servomotor 15b for rotationally driving the ball screw 15a. Become. The servomotor 15b is arranged on the device bed 11 and is electrically connected to the control device 3.

The upper slide device 2 is for feeding the adjusting wheel R, and is composed of an upper slide base 2a and a feed screw device 2b. The upper slide base 2a is a slide rail 16 provided on the lower slide base 1a.
The adjustment vehicle R and its drive source are mounted on the adjustment vehicle R.

The feed screw device 2b is for moving the upper slide base 2a, and comprises a ball screw 17a linked to the upper slide base 2a so as to be able to advance and retract, and a servo motor 17b for rotationally driving the ball screw 17a. Become. The servomotor 17b is arranged on the lower slide base 1a and is electrically connected to the control device 3.

The control device 3 automatically controls the drive sources of the grinding wheel G and the adjusting wheel R, and the servo motors 15b and 17b of the vertical slide devices 1 and 2 in conjunction with each other. CPU, ROM, RAM and I / O
It is a CNC device composed of a microcomputer including ports and the like. In this CNC device 3, a control program for executing the grinding process described below is NC
As (numerical control) data, it is appropriately and selectively set in advance by a keyboard or the like of an operation panel (not shown).

In the centerless grinding machine constructed as described above, the stepped work W supported on the blade B has its large diameter part b supported by the adjusting wheel R for braking and rotation, and has a small diameter part. After a is supported by the shoe S, the following steps of rough grinding and finish grinding are automatically and continuously performed according to the control program of the control device 3.

A. Rough grinding step: After the relative positional relationship between the adjusting wheel R and the shoe S with respect to both diameter portions a and b of the work W is set, the lower slide device 1 is driven with the upper slide device 2 stopped, The slide base 1a is fed in the feeding direction X at a predetermined constant speed.

As a result, the adjusting wheel R and the shoe S are fed at the same speed, that is, while keeping their relative positional relationship constant, and rough grinding is performed by the grinding wheel G (see FIG. 2).

B. Finishing grinding step: When the rough grinding step is completed, the lower slide device 1 is stopped and the upper slide device 2 is driven to feed the upper slide base 2a in the feeding direction X at a predetermined constant speed.

As a result, the feeding of the shoe S is stopped, and only the adjusting wheel R is fed, and the finish grinding process is performed by the grinding wheel G (see FIG. 3).

That is, at the time of rough grinding with a large grinding resistance, as shown in FIG. 2, the small diameter portion a of the work W is supported by the shoes S and the escape of the work W is effectively prevented, and the work W The large diameter portion b and the small diameter portion a are ground in the same manner.

On the other hand, at the time of finish grinding when the grinding resistance is small and the grinding resistance is small, as shown in FIG. 3, the adjusting wheel R advances slightly ahead of the shoe S (feeding direction X). The supporting state of the work W by the shoes S is released, and the work W is ground while only the large diameter portion b on the braking side is supported by the adjusting wheel R.

As a result, the work W is not affected by the relative positional relationship between the adjusting vehicle R and the shoe S with respect to the work W, and the supporting state of the work W as shown in FIG. 7 is avoided.
As a result, the two diameter portions a and b are the grinding wheel surfaces Ga and G of the grinding wheel G.
Finishing is ground while being appropriately modified by b, and high roundness and cylindricity are obtained.

Although not shown, in this example, the work W is carried in and out of the grinder by the control device 3 automatically by the carry-in / carry-out device, and a series of grinding steps are performed automatically. It is configured to be.

Embodiment 2 In this embodiment, the control program input to the control device 3 is slightly changed from that of the first embodiment.

In this example, after the same rough grinding step as in Example 1 is performed, in the subsequent finishing grinding step, the lower slide base 1a is fed as it is or at a slightly reduced speed, and the upper slide device 2 is moved. Is driven by
Each constituent device is drive-controlled so that the upper slide base 2a is fed in the feeding direction X at a predetermined constant speed.

That is, in the finish grinding step of this example, the adjusting wheel R and the shoe S are fed, and
The adjusting wheel R is driven and controlled so that the feed speed of the adjusting wheel R is higher than the feed speed of the shoe S, and the same grinding result as that of the first embodiment is obtained. Other configurations and operations are the same as those in the first embodiment.

Embodiment 3 This embodiment is shown in FIG. 4, and has a structure in which the small diameter portion a of the work W is supported by the adjusting wheel R for braking and rotation, and the large diameter portion b is supported by the shoes S. .

That is, the workpiece W targeted by this example is
Since the length of the small-diameter portion a is larger than that of the large-diameter portion b, the small-diameter portion a is selected as the braking side shaft portion so that the workpiece W can be stably braked and rotated. Other configurations and operations are similar to those of the first or second embodiment.

The above-described first to third embodiments are merely preferred embodiments of the present invention, and the present invention is not limited to this, and various design changes can be made within the scope. . For example, adjusting car R and shoe S
As a specific structure for feeding in, another structure having the same operation as that of the vertical slide devices 1 and 2 in the illustrated example can be adopted.

[0045]

As described in detail above, according to the present invention,
At the time of rough grinding with a large grinding resistance, the work is supported by the adjusting wheel and the shoe, and the large diameter part and the small diameter part are ground in the same way, while at the time of finish grinding where the grinding resistance is small and the grinding resistance is small, Since the condition that the work is supported by the shoe is released and grinding is performed while the work is supported only by the adjusting wheel, both diameters of the work may be affected by the relative positional relationship between the adjusting wheel and the shoe. Instead, finish grinding is performed while being corrected by the precisely formed grinding wheel surface of the grinding wheel, and as a result, good roundness and cylindricity can be obtained.

Further, since it is possible to prevent the influence of the relative positional relationship between the adjusting wheel and the shoe during finish grinding, it is possible to easily and quickly perform these positional adjustments, which have been very difficult in the past. The time can be greatly reduced.

[Brief description of drawings]

FIG. 1 is a schematic front view showing a centerless grinding machine that is Embodiment 1 of the present invention.

FIG. 2 is a schematic plan view explaining an operation of the centerless grinding machine during rough grinding.

FIG. 3 is a schematic plan view illustrating an operation of the centerless grinding machine during finish grinding.

FIG. 4 is a schematic plan view showing a centerless grinding machine that is Embodiment 3 of the present invention.

FIG. 5 is a schematic plan view showing a conventional centerless grinding machine for a stepped work.

FIG. 6 is a schematic plan view showing another conventional centerless grinding machine for stepped works.

FIG. 7 is a schematic plan view for explaining a work grinding state of another conventional centerless grinding machine for stepped works.

[Explanation of sign]

 W Work a Small diameter part of work (cylindrical shaft part) b Large diameter part of work (cylindrical shaft part) B Blade G Grinding wheel Ga, Gb Grinding wheel surface of grinding wheel R Adjusting wheel S Shoe X Feeding direction 1 Lower slide device 1a Lower slide base 1b Feed screw device 2 Upper slide device 2a Upper slide base 2b Feed screw device 3 Control device 10 Spinning spindle of grinding wheel 20 Spinning spindle of adjusting vehicle

Claims (5)

[Claims] 1. A method for centerless grinding the cylindrical outer diameter surface of a stepped workpiece by in-feed, wherein one diameter portion of the workpiece is braked and supported by an adjusting wheel while the other diameter portion is supported by a shoe. The step is characterized in that the adjusting wheel and the shoe are fed at the same speed during the rough grinding, and the adjusting wheel is advanced relative to the shoe during the finish grinding. Centerless grinding method for attached workpieces. 2. The centerless grinding method for a stepped work piece according to claim 1, wherein during the finish grinding, the feeding of the shoes is stopped and the adjusting wheel is fed. 3. The finishing wheel is fed with the adjusting wheel and the feeding speed of the adjusting wheel is made higher than the feeding speed of the shoe during finish grinding.
The method for centerless grinding of a stepped workpiece as described in. 4. A device for centerless grinding the cylindrical outer diameter surface of a stepped workpiece by in-feed, comprising a grindstone surface formed to accurately form a step on the cylindrical outer diameter surface of the workpiece, and rotating. The grinding wheel that drives, the adjustment wheel that supports the one diameter part of the work piece by braking, the shoe that supports the other diameter part of the work piece, the lower slide device that feeds this shoe, and the lower slide device An upper slide device for feeding the adjusting vehicle is provided, and a control device for automatically controlling the upper and lower slide devices in conjunction with each other is provided, and the control device is any one of claims 1 to 3. A centerless grinding apparatus for a stepped workpiece, which is configured to perform the grinding method according to claim 1. 5. The centerless grinding device for a stepped work piece according to claim 4, wherein the shoe is attached to a receiving plate that supports the work piece.