JPH1080853A - Automatic grinding device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an automatic grinding device which can cut off large burrs without leaving an uncut part, and can make the finishing surface smooth. SOLUTION: This automatic grinding device is composed of a movablc main body 10 movable three-dimeisionally; a grinder main body 20 to hold a grinding wheel 1, and journalled by the movable main body 10; a spring member 30 provided between the movable main body 10 and the grinder main body 20, and to energize the grinding wheel 1 to a workpiece member in its pressing direction; a robot arm to move the movable main body 10; motors; a motor to rotate the grinding wheel 1; and a inclination sensor to detect the inclination of the grinder main body 20. In this case, when the detected inclination R of the grinding wheel 1 is made less than a set value TH from a standard value R0 , the movement of the movable main body 10 is stopped, and the grinding wheel 1 is weaving operated, and when the inclination R exceeds the set value TH, the weaving operation is stopped so as to carry out a control to restart the movement of the movable main body 10.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an automatic grinding apparatus for automatically cutting and removing burrs and the like on a processing surface by causing a grinder supporting a grindstone to follow a processing surface of a workpiece such as a casting by a robot arm or the like. About.

[0002]

2. Description of the Related Art Conventionally, the same type is disclosed in, for example,
No. 328906 and Japanese Utility Model Publication No. 5-21315. The former includes a support base attached to the movable body, a support plate attached to the support base via an elastic body, and a detector attached to the support base,
A disk grinder attached to the support plate and equipped with a grindstone. When the grindstone during cutting feed strikes a large burr of the workpiece (workpiece), the disc grinder is applied when a certain force or more is applied to the grindstone. Pushed up,
When this is detected by the detector, the cutting feed of the disc grinder is stopped, the burr is cut by the pressing force of the whetstone by the elastic body, and after the cutting and removal is completed, the disc grinder returns to the original state again, and the detector detects this. The burr is cut and removed by sensing and restarting the cutting feed by the movable body.

On the other hand, in the latter, a support arm is fixedly provided at the tip of a robot arm, and a grinder for supporting the grindstone is supported by a spindle so that the grindstone can approach and separate from a processing surface of a workpiece (workpiece). The support arm is provided rotatably via a support arm, and a spring is provided on the support shaft for urging the rotating power so that the grindstone is pressed toward the processing surface, and the rotation angle of the grinder with respect to the support arm is predetermined. Each of the support arms is provided with a pair of limit switches for detecting whether a predetermined rotation angle in each of the rotation directions has been reached, and when the limit switches detect that the grindstone has rotated in a direction away from the processing surface. Operates the robot arm so that the whetstone moves away from the processing surface, and when the limit switch detects that the whetstone has rotated in the direction approaching the processing surface, the whetstone approaches the processing surface Yo provided a robot controller for operating the robot arm is obtained by such processing is performed with a constant pressing force.

[0004]

However, according to the former Japanese Patent Application Laid-Open No. 7-328906, when the grindstone hits a large burr of the workpiece, the pressing force of the grindstone by an elastic body such as a spring is applied. Since the large burrs are cut, there is a problem that the finish of the large burrs becomes rougher than the surrounding portions. Also,
The detector reacts when the grinding wheel hits a large burr and the disc grinder is pushed up with a certain force or more, stops cutting feed, and increases the pressing force of the whetstone at the stopped position to cut large burr. However, in reality, there is a problem that a control response is delayed from the moment when the grindstone comes into contact with the large burr until the cutting feed is stopped, and as a result, the first portion of the large burr is left uncut.

On the other hand, according to the latter Japanese Utility Model Publication No. Hei 5-21315, if it is known that a large burr is present on a workpiece, it is necessary to perform rough finishing and high-precision finishing twice. There is a problem that it takes time. Also,
There is a problem that it is not possible to cope with a case where a grindstone suddenly hits a large burr.

An object of the present invention is to provide an automatic grinding apparatus capable of reliably cutting large burrs without leaving uncut portions and smoothing a finished surface.

[0007]

In order to achieve the above object, an automatic grinding apparatus according to the present invention supports a movable main body (10) movable two-dimensionally or three-dimensionally and a grindstone (1). ,
And a grinder body (2) pivotally supported by a movable body (10).
0) and a spring member (30) interposed between the movable main body (10) and the grinder main body (20) and biasing the grindstone (1) in the direction of pressing against the processing surface of the workpiece (W). , Moving means (40, Ma, M) for moving the movable body (10)
b, Mc, Md, Me, Mf), rotation drive means (Mg) for rotating the grindstone (1), and angle detection for detecting the inclination angle of the grinder body (20) with respect to the processing surface of the workpiece (W). When the inclination angle (R) of the grinding wheel (1) detected by the means (Sn) and the angle detection means becomes smaller than the set value (TH) from the normal reference value (R ₀ ), the transfer means (40, Ma, Mb, Mc, Md, Me, Mf)
The moving means (40, Ma, M) stops the movement of the movable body (10) due to the weaving operation of reciprocating the grindstone (1) repeatedly back and forth around the stop position.
b, Mc, Md, Me, Mf), and when the inclination angle (R) of the grindstone (1) exceeds the set value (TH) during the weaving operation, the weaving operation is stopped and the conveying means (40, Control means (51) for restarting the movement of the movable body (10) by Ma, Mb, Mc, Md, Me, Mf) (claim 1).

In addition, the rotation of the grinder body (20) about the support shaft with respect to the movable body (10) is restricted so that the inclination angle (R) of the grindstone (1) becomes larger than the reference value (R ₀ ). It is preferable to add a stopper mechanism (4) for preventing this.

Further, the grinder body (2) interposed between the movable body (10) and the grinder body (20) and rotating in a direction in which the inclination angle (R) of the grindstone (1) decreases.
It is preferable to add a shock absorber (70) that loosens the displacement speed of 0) as compared with the case of rotating in the direction of increasing the displacement (claim 3).

It is preferable that a pressing force changing means (60) for changing the pressing force by the spring member (30) is added (claim 4).

Further, the control means (51) includes a movable body (1).
According to the posture information of 0), the pressing force of the spring member (30) is varied via the pressing force changing means (60), and the contact of the grindstone (1) is performed regardless of the posture of the movable body (10). It is preferable that the pressing force applied to the processing surface of the workpiece (W) is kept constant by the above method.

Symbols in parentheses indicate corresponding elements or items in the description of the embodiments of the present invention described later with reference to the drawings.

According to the first aspect of the present invention, when the detected inclination angle of the grindstone becomes equal to or less than the set value, the control means sets the following.
That is, when the grindstone collides with a large burr and the inclination angle decreases, the movement of the movable body is stopped, and a weaving operation is performed in which the grindstone is reciprocated finely back and forth around the stop position. As a result, large burrs are gradually but surely cut by the reciprocating motion of the grindstone. Since the surface is gradually cut in this manner, the finished surface is smooth and clean. When the inclination angle of the grindstone exceeds the set value during the weaving operation, that is, when a large burr is completely cut, the weaving operation is stopped and the movement of the movable main body by the transfer means is restarted. The small burrs can be reliably cut only by moving the movable body by the transport means.

According to the second aspect of the present invention, the addition of the stopper mechanism limits the rotation of the grinder body about the support shaft with respect to the movable body, and prevents the inclination angle of the grindstone from becoming larger than the reference value. Therefore, excessive grinding exceeding the target grinding allowance is reliably prevented.

Further, according to the third aspect of the present invention, the displacement speed of the grinder body rotating in the direction in which the angle of inclination of the grindstone becomes smaller is reduced by the addition of the shock absorber. Even if the grindstone hits the burr generated in and changes so that the inclination angle decreases, the grindstone does not inadvertently separate from the processing surface of the workpiece, and
When the inclination angle changes so as to increase, the follow-up of the grindstone to the workpiece is quickly and stabilized, so that a clean and smooth ground surface can be obtained.

According to the fourth aspect of the present invention, since the pressing force of the spring member can be changed by adding the pressing force changing means, the setting of the grinding force is facilitated.

According to the fifth aspect of the present invention, the pressing force of the spring member is automatically varied via the pressing force changing means in accordance with the posture information of the movable body, and the posture of the movable body is changed. Irrespective of the above, the pressing force applied to the processing surface of the workpiece by the contact of the grindstone is made constant, so that the grinding is stabilized.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An automatic grinding apparatus according to an embodiment of the present invention will be described with reference to the drawings. FIG. 1 is an external view showing the entire system of the automatic grinding apparatus according to the present embodiment,
FIG. 2 is an enlarged front view showing the grinding unit 100 of FIG. 1, and FIG. 3 is a side view of FIG. This automatic grinding device
It mainly functions as the movable main body 10, a grinder main body 20 pivotally supported by the movable main body 10, a spring member 30 interposed between the movable main body 10 and the grinder main body 20, and a transport means for moving the movable main body 10. A robot arm 40,
A motor Mg functioning as a rotation driving means for rotating the disc-shaped grindstone 1 rotatably supported at the tip of the grinder body 20, and an inclination angle of the grinder body 20 with respect to a processing surface of a workpiece W is detected. And a control unit 50 for controlling the entire apparatus. The motor for rotating the grinding wheel 1 is housed in the grinder body 20. Reference numerals 11 and 12 indicate protective covers. The grinder body 20 is, for example, an electronic grinder known from Japanese Patent Application Laid-Open No. 2-95563, and is controlled to keep the rotation speed constant even when the rotation load fluctuates.

The movable body 10 has a substantially arm shape and is attached to the distal end of a robot arm 40 of a six-axis control articulated robot known per se.
(Y axis, Y axis, Z axis direction). Movable body 1
0 denotes six motors (Ma, Mb, Mc, M
d, Me, Mf) to drive the posture up, down,
It can be changed diagonally.

The grinder body 20 supporting the grindstone 1 includes:
The rear end of the grinder body 20 is rotated around the support shaft 2 with respect to the movable body 10. A stopper 4 is provided, which is extendable and contractible in the left-right direction of FIG. As a result, the rotation of the grinder main body 20 around the support shaft 2 with respect to the movable main body 10 is restricted, and the inclination angle R of the grindstone 1 becomes equal to the reference value R _0.
(In this embodiment, the angle is set to 20 degrees). Therefore, excessive grinding exceeding the target grinding allowance is reliably prevented.

The spring member 30 is a coil spring that urges the grindstone 1 against the processing surface of the workpiece W, that is, biases the tip end of the grinder body 20 that supports the grindstone 1 in a direction away from the movable body 10. is there. In addition, a leaf spring can be used. A pressing force changing mechanism 60 that can arbitrarily change the pressing force of the spring member 30 is provided on the movable body 10 side. Pressing force changing mechanism 60
Are a pressing plate 61 which abuts (may be locked) on one end of the spring member 30, a vertical rod 62 having one end fixed to the pressing plate 61 and having a thread cut in the center, and a screw of the vertical rod 62. , A servomotor Ms for rotating the rotary nut 63 via a bevel gear 64, and an elevating guide 65 for preventing rotation of the vertical rod 62. By controlling the rotation of the servomotor Ms, The pressing force by the spring member 30 can be freely changed. Thus, the grinding force can be easily changed. Note that, without using the servomotor Ms, a mechanism may be used in which the rotating rod 63 is manually rotated to move the vertical rod 62 up and down to change the pressing force by the spring member 30. According to this, the entire device is reduced in weight and the structure is simplified.

A hydraulic shock absorber 70 is interposed between the movable body 10 and the grinder body 20 substantially parallel to the spring member 30. The shock absorber 70 is a hydraulic actuator in which a throttle valve 71 and a check valve 72 are provided in parallel as shown in FIG. 4 and the speed of oil flowing from the upper chamber 73 to the lower chamber 74 is reduced. According to this, the displacement speed of the grinder body 20 that rotates in the direction in which the inclination angle R of the grindstone 1 becomes smaller can be relaxed as compared with the case where the grinder body 20 rotates in the direction in which the grindstone 1 becomes larger. When the grindstone 1 collides with the burr B generated on the processing surface and changes so that the inclination angle R becomes small, the grinding stone 1 does not inadvertently separate from the processing surface of the workpiece W, and the inclination angle R becomes small. When it changes so as to increase, the follow-up of the grindstone 1 to the workpiece W is quickly and stabilized, so that a clean and smooth ground surface can be obtained.

The inclination angle sensor Sn comprises a rotary encoder, and detects the inclination angle R of the grindstone 1 by detecting the inclination angle of the grinder body 20 with respect to the processing surface of the workpiece W. Note that an inclination angle sensor such as another potentiometer, a differential transformer, or a resolver may be used. Or PSD (semiconductor position detecting element)
The angle may be analyzed using a sensor.

As shown in FIG. 5, the control unit 50 includes a CPU 51 for performing control and a RAM 5 serving as a storage unit.
2, a ROM 53 for inputting a work pattern, an operation display unit 54 for inputting a set value of a spring pressing force, a set value of an inclination angle of the grindstone 1, and the like, a motor driving driver 55, and the like.

Next, the processing contents of the CPU 51 will be described with reference to FIG. When the power is turned on, the CPU 51 performs initialization (step 1; hereinafter, the word "step" is omitted in parentheses). In the initialization, an internal timer, a counter and the like are set to initial values (n ← 1). Then, the work pattern is input from the operation display unit 54 (2), and the pressing force of the spring member 30 is set based on the initial posture of the movable body 10 (3).

For example, the initial posture of the movable body 10 is shown in FIG.
If it is upward as shown in FIG.
By setting 0, the pressing force of the spring member 30 is set to 2 kg. In this case, the pressing force applied to the processing surface of the workpiece W by the contact of the grindstone 1 is 7 kg obtained by adding 5 kg of the weight of the grinding unit 100 to 2 kg. Alternatively, if the initial posture of the movable body 10 is horizontal as shown in FIG. 7B, the pressing force of the spring member 30 is set by the pressing force changing mechanism 60 to 7 kg. In this case, since the weight (5 kg) of the grinding unit 100 is not applied to the pressing force applied to the processing surface of the workpiece W due to the contact of the grindstone 1, the pressing force is 7 kg. Alternatively, if the initial posture of the movable body 10 is downward as shown in FIG.
Is set to 12 kg. In this case, the pressing force applied to the processing surface of the workpiece W by the contact of the grindstone 1 is 7 kg obtained by adding -5 kg of the grinding unit 100 minus 5 kg to the 12 kg. Thus, regardless of the posture of the movable body 10, the pressing force applied to the processing surface of the workpiece W by the contact of the grindstone 1 is always constant (7 k).
g). Therefore, stable and stable grinding force is exhibited.

Next, the CPU 51 turns on and rotates the motor Mg for rotating the grindstone 1 (4), and moves the grinding unit 100 via the robot arm 40 along the input work pattern. At the same time, the posture of the grinding unit 100 is controlled (5). Grinding unit 1
When the posture of 00 changes as shown in FIG. 7 (6), the spring pressing force is automatically set based on the changed posture (7). For example, if the posture of the grinding unit 100 changes from upward to lateral, the pressing force of the spring member 30 is reduced by 2 k.
The pressing force is changed from 7 kg to 12 kg when changing from g to 7 kg, from 12 kg to 7 kg when changing from down to side, and from 7 kg to 2 kg when changing from side to upward. Although the posture of the grinding unit 100 can be easily obtained from the rotation angle of the motor that rotates the grinding unit 100, a detector such as a gyro sensor for detecting the posture of the grinding unit 100 itself may be separately provided.

Next, the CPU 51 checks whether or not the work has been completed (8), and if completed, stops each motor (9).
The value R of n is read at regular intervals (10), and the value R is compared with a set value TH (18 degrees in this embodiment) (11). As shown in FIG. 8, when the grindstone 1 hits a small burr Bs, the inclination angle R becomes the reference value R ₀ (20 degrees).
Most does not change, since the inclination angle R ₁ indicates a movement of the grinding wheel 1 is separated from the workpiece W is considerably small when bumped large burrs Bt, less defines the set value TH inclination angle R from , It is detected that the grinding wheel 1 has hit a large burr Bt.

If it is determined in step 11 that the inclination angle R is larger than the set value TH, that is, if the grindstone 1 does not hit the large burr Bt, the process returns to step 6, and the posture of the grinding unit 100 in the middle of the work and the completion of the work are repeatedly checked. . At this time, the small burrs Bs are easily removed while the robot arm 40 moves. On the other hand, when the inclination angle R becomes equal to or less than the set value TH, that is, when the grindstone 1 hits a large burr Bt, the CPU 51 stops the movement of the robot arm 40 (12) and performs the weaving operation (13). This weaving operation is described in FIG.
As shown in the movement of m, the grindstone 1 is reciprocated finely back and forth around the stop position, and the larger burr Bt is reliably cut, and the finished surface becomes smooth. . Specifically, this is performed by repeating the motor for moving the robot arm 40 in a forward rotation, a reverse rotation, a forward rotation,... Every short time.

When the weaving operation is performed, the large burrs Bt are gradually cut. Therefore, the value R of the inclination angle sensor Sn is read during the weaving operation (14), and the value R exceeds the set value TH, and the large burrs Bt are removed. It is checked whether or not has been removed (15, 16, 17). This check is performed a predetermined number of times (three times in the present embodiment) in order to ensure reliability. If the inclination angle R exceeds the set value TH three times or more, the counter n is reset to 1 (18), and the weaving operation is stopped (1).
9), the movement by the robot arm 40 is restarted (20). Thereafter, the process returns to step 6 and repeats the above processing until the work is completed.

By the above processing, the workpiece W
From the small burrs Bs generated on the surface to be processed to the large burrs Bt, the finished surface is smooth and clean.

[0032]

As described above, according to the first aspect of the present invention, when the grindstone hits a large burr, the movement of the movable body is stopped and the weaving operation is performed. Although it is cut gradually but surely, the finished surface is smooth and clean. According to this, although it is necessary to reciprocate the grindstone for a large burr portion, it is not necessary to perform rough finishing and high-precision finishing twice from the beginning to the end as shown in the conventional example. So don't waste your time.

According to the second aspect of the present invention, the addition of the stopper mechanism reliably prevents excessive grinding exceeding the target grinding allowance. Furthermore, according to the third aspect of the present invention, the addition of the shock absorber makes the follow-up of the grindstone to the workpiece to be processed quickly and stable, so that a cleaner and smoother ground surface can be obtained.

According to the fourth aspect of the present invention, since the pressing force of the spring member can be changed by adding the pressing force changing means, the setting of the grinding force is facilitated. According to the fifth aspect of the present invention, the pressing force of the spring member is automatically changed via the pressing force changing means in accordance with the posture information of the movable main body, regardless of the posture of the movable main body. Since the pressing force applied to the processing surface of the workpiece by the contact of the grindstone is made constant, the grinding is stabilized.

[Brief description of the drawings]

FIG. 1 is an external view showing an entire system of an automatic grinding device according to an embodiment of the present invention.

FIG. 2 is an enlarged front view showing the grinding unit 100 of FIG.

FIG. 3 is a side view of FIG. 2;

FIG. 4 is a block diagram showing a schematic configuration of a shock absorber 70 shown in FIG.

FIG. 5 is a block diagram showing a schematic configuration of an electric system of the automatic grinding apparatus according to the embodiment of the present invention.

FIG. 6 is a flowchart showing processing contents of a CPU 51 shown in FIG. 5;

FIGS. 7A and 7B are state diagrams showing aspects of a change in posture of the grinding unit 100 shown in FIG. 1, wherein FIG.
Indicates the case of horizontal orientation, and (c) indicates the case of downward orientation.

FIG. 8 is a state diagram showing a movement of the grindstone 1 with respect to a processing surface of a workpiece W;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Whetstone 2 Support shaft 3 Adjusting screw 4 Stopper 10 Movable main body 20 Grinder main body 30 Spring member 40 Robot arm with trolley 50 Control unit 60 Pressing force changing mechanism 61 Holding plate 62 Vertical rod 63 Rotating nut 64 Bevel gear 65 Lifting guide 70 Buffering device 71 Throttle valve 72 Check valve 73 Upper chamber 74 Lower chamber 100 Grinding unit R Inclination angle W Workpiece B, Bs, Bt Burr Sn Inclination angle sensor Ma, Mb, Mc, Md, Me, Mf Motor Mg motor for rotating grindstone Ms Servomotor for variable pressing force

Claims (5)

[Claims] A movable body that is movable two-dimensionally or three-dimensionally, a grinder body that supports a grindstone and is supported by the movable body, and is interposed between the movable body and the grinder body; A spring member for urging the grindstone in a direction for pressing the grindstone against the processing surface of the workpiece, a conveying means for moving the movable body, a rotation driving means for rotating the grinding stone, and the grinder for the processing surface of the workpiece. An angle detecting means for detecting an inclination angle of the main body, and when the inclination angle of the grindstone detected by the angle detecting means becomes smaller than a set value from a normal reference value, the movement of the movable main body by the transport means is stopped. The weaving operation for reciprocating the grindstone by repeatedly finely moving back and forth around the stop position is performed via the transfer means, and the inclination angle of the grindstone is set during the weaving operation. Automatic grinding apparatus characterized by and a control means for restarting the movement of the movable body by said conveying means to stop the weaving operation exceeds the value. 2. A stopper mechanism for restricting rotation of the grinder body around a support shaft with respect to the movable body to prevent the inclination angle of the grindstone from becoming larger than a reference value. 2. The automatic grinding device according to 1. 3. The displacement speed of the grinder body, which is interposed between the movable body and the grinder body and rotates in a direction in which the inclination angle of the grindstone decreases, is compared with a case in which the grinder body rotates in a direction in which the inclination angle increases. The automatic grinding device according to claim 1 or 2, further comprising a buffer device for loosening. 4. The apparatus according to claim 1, further comprising a pressing force changing means for changing a pressing force of said spring member.
The automatic grinding device according to claim 3. 5. The grinding means according to claim 1, wherein said control means varies the pressing force of a spring member through said pressing force changing means in accordance with the posture information of said movable body, and contacts said whetstone regardless of the posture of said movable body. 5. The automatic grinding apparatus according to claim 4, wherein the pressing force applied to the processing surface of the workpiece is made constant.