JPH0679607A - Device for grinding crank pin journal - Google Patents

Abstract

PURPOSE: To simultaneously grind plural crankpin journals while rotating a crankshaft. CONSTITUTION: For grinding plural crankpin journals 50, plural abrasive belts 96 corresponding to them are run along a roughly perpendicular passage to a crankshaft C. During rotation of the crankshaft C, running passages of the abrasive belts 96 are variously changed in accordance with the position of the crankpin journals 50 around a longitudinal center line of the crankshaft C, while the respective abrasive belt 96 is guided regardless of the other abrasive belts 96 to let the abrasive belts 96 constantly in contact with the crankpin journals 50. Each belt 96 may be guided by a thin, flat blade on which the belt 96 slides, or it may be guided by a freely rotatable roller 200 in substantially frictionless contact with the belt 96.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION This invention relates generally to grinding machines and, more particularly, to a method and apparatus for grinding the crankpin journal of a crankshaft with an abrasive belt.

[0002]

2. Description of the Related Art At present, the most common method for grinding a crankpin journal of a crankshaft is
Only one crankpin journal is ground at a time. In this case, the grinding operation is performed by rotating the crankshaft with the longitudinal centerline of one of the plurality of crankpin journals as the rotation axis, and while the crankshaft is rotating, the surface of the crankpin journal is ground with a grinding wheel. This is done by grinding. Before grinding the next journal, the crankshaft must be indexed so that the longitudinal centerline of the next journal is the axis of rotation. Grinding only one crankpin journal at a time and pre-indexing the crankshaft each time is time consuming and cumbersome.
In addition, since the crankshaft is rotated about the centerline of the journal located at a position deviated from the centerline of the crankshaft itself, the unbalance occurs. The unbalance causes wear, and sometimes the grinding condition of the crankpin journal is insufficient.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to mount a crankshaft on a grinding machine only once and rotate the crankshaft about a centerline of the crankshaft itself in the longitudinal direction as a rotary shaft, thereby making it possible to provide a plurality of crankshafts. To simultaneously grind each of the crankpin journals with separate abrasive belts, thereby eliminating the need for crankshaft indexing and the potential for unbalance.

[0004]

SUMMARY OF THE INVENTION A grinding machine according to the present invention is adjacent to a crankshaft because it grinds all crankpin journals simultaneously while the crankshaft is rotating about its own longitudinal centerline. In position, there are a plurality of abrasive belts each supported against the crankpin journal. While each crankpin journal revolves around the longitudinal centerline of the crankshaft, each abrasive belt is individually guided to its point of contact with the crankpin journal, varying its path. . The guide of the polishing belt is performed by a shoe that contacts the back surface of the polishing belt. Each shoe moves toward and away from the centerline of the crankshaft, independent of the movement of the other shoes. To keep the polishing belt in contact with the crankpin journal during the rotation of the crankshaft, monitor the angular position of the crankshaft during rotation and attach the polishing belt at the contact point between the polishing belt and the crankpin journal. CN to show the shoe
C control is preferable. Each shoe can be in the form of a thin flat blade on which the belt slides. Or
It is preferable that the roller has a rotatable structure such that the peripheral surface of the roller comes into contact with the belt in a rotating state and in a substantially frictionless state.

[0005]

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

The grinding device 10 has a base 12. A slide assembly 14 for supporting a work is mounted on the base 12. In the case of this example, the work is a long crankshaft C (FIGS. 2 and 3). The slide assembly 14
It includes a slide base 16 fixed to a base 12.
Parallel bars 18 on slide base 16 slidably support table 20, so that table 20 is moved along parallel bars 18 by drive ball screw 22 (FIG. 2) driven by reversible motor 24. . A headstock 26 is attached to one end of the table 20 by a bracket 28. Tailstock located at the other end of table 20
30 (FIG. 3) is slidable on a guide surface 32 attached to a support 34 fixed to the table 20. Guide surface 32
Is mounted parallel to the parallel rod 18, so the tailstock 30 can be moved by the servomotor 36 and the drive ball screw 38.
Can be moved toward or away from the headstock 26. Both ends of the crankshaft C are held by collet chucks 40 and 42 which are rotatably mounted on the headstock 26 and tailstock 30, respectively. Servo motor mounted on headstock 26
By driving the collet chuck 40, 44
The crankshaft C is rotated with its longitudinal centerline as the axis of rotation.

The crankshaft C is a long member having crank arms 46 (FIG. 2) arranged at equal intervals in the longitudinal direction. The crank arms 46 extend radially outwardly from the centerline of the crankshaft C at different angular positions about the centerline. Each crank arm 46 has parallel side plates 48. The side plate 48 supports a cylindrical crankpin journal 50 near its outer end. These crankpin journals 50 are cylindrical members, and their axial centers are parallel to the longitudinal centerline of the crankshaft C, but are radially displaced therefrom.

The base 12 has a horizontal extension 52,
A plurality of (three in this example) grinding units 54, 56 and 58 are mounted thereon. These grinding units are provided for the purpose of grinding the cylindrical surface of the crankpin journal 50 of the crankshaft C.

Each grinding unit includes a frame with two laterally spaced parallel plates 60 and 62. These side plates lie in a plane that is at a right angle to the crankshaft C, and thus also at a right angle with the parallel rods 18 supporting the table 20 on which the crankshaft C is mounted. Side plate of each grinding unit
60 is fixed to a saddle 64 that moves on a guide surface 66 that is at a right angle to the parallel bar 18 that supports the table 20. The saddle 64 is moved along the guide surface 66 by the drive ball screw 68 driven by the servo motor 70. The grinding units 54, 56 and 58 are parallel to each other and move along parallel movement paths.

The side plate 62 of each grinding unit is in parallel with the side plate 60 as shown, with spacer block 72
It is fixed to the side plate 60 by any suitable means including. At the rear end of the side plates 60 and 62 of each grinding unit is a shaft 74. The shaft 74 rotates while being supported by two side plates and a bearing block 76 (FIG. 2) attached to the side plate 62. A pulley 78 is mounted on the shaft 74 such that it can rotate integrally with the shaft 74 between the two side plates, and a collar 80 allows the shaft 74 to rotate.
It is fixed to. Above the front end of each grinding unit is a shaft 82. The shaft 82 has two side plates
It rotates while being supported by 60 and 62 and a bearing block 84 attached to the side plate 62. Pulley 86
Shaft 82 for free rotation between the two brims 88
Is attached to. A similar shaft 90 below the front end of each grinding unit rotates while resting on two side plates 60 and 62 and a bearing block 92 (FIG. 3). A pulley 94 is mounted on the shaft 90 for free rotation between the two collars 95. Flexible endless polishing belt 96
Hangs over 78,86 and 94. The polishing belt 96 has a polishing surface on the outer side and a base material surface having no polishing property on the inner side. A predetermined tension is applied to the polishing belt 96 by a roller 98 attached to one end of the leaf spring 100. The other end of the leaf spring 100 is fixed to a shaft 102 supported by two side plates 60 and 62. Polishing belt
96 is on a plane perpendicular to the crankshaft C. The abrasive belts of the three grinding units 54, 56 and 58 are separated from each other by a multiple of the distance between the crank arms on the crankshaft (in this example, a multiple of 2).

Power for driving the polishing belts of the three grinding units is supplied from a motor 104 attached to the horizontal extension portion 52. The motor 104 rotates a shaft 106 supported by a bearing block 108 on the horizontal extension 52. The shaft 106 has three timing belt pulleys 110, 11 at regular intervals.
2 and 114 are fixed so that they can rotate together with the shaft 106. The shaft 74 of each grinding unit is provided with an extension to which the timing belt pulleys 116, 118 and 120 are attached. One timing belt is attached to each grinding unit. That is, the timing belt 122 is wound around the pulleys 110 and 116, the timing belt 124 is wound around the pulleys 112 and 118, and the timing belt 126 is wound around the pulleys 114 and 120, respectively. Each timing belt comes with belt fasteners. The belt fastener includes roller 128. The roller 128 is mounted on an arm 130 supported by the side plate 60 and is biased by spring tension into contact with the timing belt. With such a configuration, the motor 104 supplies power for linearly moving the polishing belts of the three grinding units in the direction of arrow 131.

Each grinding unit is provided with a shoe 132 for guiding the polishing belt at a position where the polishing belt contacts the crankpin of the crankshaft. This shoe is attached to the side plate 60 by the key 136.
134 (FIG. 2) and a tip portion 138 that compresses the backside of the polishing belt between idler pulleys 86,94.

The tip portion 138 is in the form of an elongated sheet or flat blade that is coplanar with the polishing belt. Since the length of the tip portion 138 is larger than the diameter of the circle drawn by the crankpin journal when the crankshaft is rotating,
While the crankpin journal revolves around the centerline of the crankshaft, the abrasive belts continue to be squeezed on the backside by the tip portion 138 and maintain contact with the crankpin journal. The front surface 140 (FIG. 7) of the tip portion 138 is flat and perpendicular to the plane formed by the abrasive belt 96, and only at the point of contact between the abrasive belt and the crankpin journal during revolution of the crankpin journal. Instead, the polishing belt is guided on the upper side and the lower side of the contact point. The tip portion 138 has a side surface 141.
The side surface 141 extends perpendicularly to the front surface 140 from both edges of the front surface 140. The side surfaces 141 on both sides are separated from each other by a distance smaller than the width of the polishing belt 96.

In each of the grinding units, the polishing belt 96 is bent from the normal flat state to the side of the tip portion 138 from a normal flat state to a state in which the cross section is substantially U-shaped.
At the portion where the polishing belt comes into contact with the tip portion 138, not only does the polishing belt contact the front surface 140 of the tip portion 138 as shown in FIG.
Two sets of idle rollers 145 and 147 are provided above the tip portion 138 so as to contact the side surfaces 141 on both sides of 138. These Idol Laura 145
And 147 are rotatably mounted on the side plates 60 and 62. The idle rollers 145 and 147 are shown in FIGS.
, But not shown in FIG. 1 to avoid complexity.

As shown in FIG. 7, the total width of the tip portion 138 and the bent portion of the polishing belt 96 is slightly narrower than the width of the crankpin journal 50. Therefore, when it is necessary to grind the entire circumference of the crankpin journal, the table 20
It may be necessary to reciprocate the crankshaft C. When the table 20 is reciprocated, the inner surface of the side plate 48 of the crank arm 46 is also ground by the bent portion of the polishing belt.

As shown in FIG. 6, the idle roller 145
Is installed at an angle such that its peripheral surface forms an angle of about 45 ° with the polishing surface of the polishing belt 96. On the other hand, the idle roller 147 has a polishing belt 96 on its circumferential surface.
At an angle of about 90 °, or preferably slightly greater than 90 °, with respect to the polishing surface. Therefore, the idle roller 147 completes the bending, and the edges of the polishing belt on both sides are 90 °.
Since it is bent at an angle slightly larger than that, when the portion reaches the tip portion 138, the edge portions on both sides of the polishing belt exert a light tightening action on both side surfaces of the tip portion 138.

Two sets of idle rollers 148 and 150 are provided below the tip portion 138 of each grinding unit as idle rollers contacting the polishing belt 96 below the tip portion 138. Idol Laura is also not shown in Figure 1). These idle rollers 148 and 150 are rotatably mounted on the side plates 60 and 62. Idol Laura 148
Is installed at an angle such that its peripheral surface forms an angle of about 90 ° with the polishing surface of the polishing belt 96. These idle rollers 148, along with the idle rollers 147, keep the abrasive belt 96 folded along the surface of the tip portion 138. The idle roller 150 is installed at a certain angle so that its peripheral surface forms an angle of about 45 ° with the polishing surface of the polishing belt 96, and thereby the polishing belt is expanded in the middle. When the abraded portion reaches roller 94, the abrasive belt returns to its normal, perfectly flat condition.

The servomotor 70 for moving the grinding units 54, 56 and 58 toward and away from the crankshaft C is preferably controlled by a CNC numerical controller. Servo motor for rotating the crankshaft
The feedback device 45 attached to the 44 feeds back to the numerical control device information regarding the rotation of the drive ball screw, that is, information regarding the angular position during rotation of the crankshaft, so that the numerical control device can make corrections as necessary. To keep the polishing belt in contact with the crankpin journal while the crankshaft is rotating,
The servo motor 70 of the grinding unit is operated.

To operate the grinding apparatus according to the present invention, first, the table 20 is moved by the reversible motor 24 to a position where the three crankpin journals face the polishing belts of the three grinding units 54, 56 and 58. Let Then, the three grinding units are advanced by the servomotor 70 to bring the polishing belt into contact with the crankpin journal. Next, the servomotor 44 rotates the crankshaft C. The feedback device 45 feeds back information about the angular position of the crankshaft C during rotation to the numerical control device. To keep the polishing belt in contact with the crankpin journal during rotation of the crankshaft,
The numerical controller drives the servomotors 70 of the three grinding units for each.

After finishing the roughing or finishing of the three crankpin journals, the grinding unit is retracted,
The table 20 is moved and the above procedure is repeated in order to face the other three crankpin journals to the polishing belts of the three grinding units.

If the crankpin journal is longer than the width of the bent abrasive belt, the crankpin
If it is desired to grind the entire length of the journal, the table 20 may be vibrated during the grinding operation.

8 and 9 show a modified embodiment in which the roller 200 is the shoe which guides the grinding belt 96 of each grinding unit at the point of contact with the crankpin. Each roller 200 is mounted on a support block 202, which is pressed by means of a key 204 on the side plate 60 of the grinding unit.
It is fixed to. The roller is a shaft 20 parallel to the crankshaft C.
It is rotatable around 6 and its peripheral surface is in contact with the back surface of the polishing belt.

The roller 200 has a cylindrical shape and is positioned on the surface of the grinding belt that supports it. The axis of rotation of this roller is
The roller moves together with the frame of the grinding unit to which the roller is attached along a path that traverses the longitudinal axis of the crankshaft. The diameter of the roller is larger than the diameter of the circle drawn by the crankpin journal with which the supporting grinding belt contacts. Further, the tip of the roller 200 protrudes toward the crankshaft side from the pulleys 86, 94 for the grinding belt, whereby the grinding belt is hung in a sufficient range around the circular arc portion at the tip, and the belt is , Point 208 and
It is supported between 210 and is in continuous contact with the crankpin journal over the entire circumference of a circle drawn about the crankshaft. Attention is paid to the position where the roller and the grinding belt are indicated by a two-dot chain line in FIG. The thickness of the roller, that is, the distance between the sides, and the width of the belt
Formed smaller than the distance between the crank arm side plates 48 for the journal 50, the belt and roller project between the crank arms to provide a 360 ° circumference around the crankpin journal as the crankshaft rotates 360 °. Grinding is possible over the entire range of °.

The roller 200 is not driven, but is rotated by contact with the substantially frictionless grinding belt and rotates continuously with the grinding belt without slippage. This point is different from the first embodiment in which each belt slides on the surface of the tip portion of the shoe. In this way, the roller performs a backup function without causing any noticeable abrasion of the belt due to rubbing.

Except as described and illustrated above,
The embodiment of FIGS. 8 and 9 is similar to the embodiment of FIGS. 1-7 and its operation is the same.

[0026]

Since the grinding apparatus according to the present invention has the above-mentioned features, it is strong, durable, efficient, relatively easy to manufacture, and easy to operate. Further, since the rotating roller guides the belt, abrasion of the polishing belt due to rubbing can be effectively prevented.

[Brief description of drawings]

FIG. 1 is a side view of a grinding device according to the present invention.

2 is a partially cutaway plan view of the grinding device shown in FIG. 1. FIG.

FIG. 3 is a partially cutaway rear view of the same device.

FIG. 4 is a partial side view showing the polishing belt of the grinding apparatus shown in FIG. 1 in contact with one of the crankpin journals.

5 is a diagram showing a state seen in a direction of an arrow 5 in FIG.

6 is a diagram showing a state seen in the direction of arrow 6 in FIG.

7 is a partial cross-sectional view taken along the line 7-7 in FIG.

FIG. 8 is a partial view showing a modified example of a portion similar to the portion shown in FIGS. 1 to 4.

9 is a partial cross-sectional view taken along the line 9-9 in FIG.

[Explanation of symbols] 10 Grinding device 46 Crank arm 50 Crank pin journal 54 Grinding unit 56 Grinding unit 58 Grinding unit 70 Servo motor 96 Abrasive belt 200 Roller 206 Axis C Crankshaft

Claims (6)

[Claims] 1. A device for grinding the peripheral surface of a plurality of cylindrical crankpin journals arranged at intervals in the longitudinal direction of a long crankshaft, each crankpin journal having a predetermined position. Are installed on a pair of crank arms that extend radially outward from the crankshaft and are spaced apart in the lengthwise direction, and the center of the crankpin journal is around the longitudinal centerline of the crankshaft. Radial outwards from this centerline at different angular positions, and the entire 360 ° circumference of the crankpin journal is laterally accessible for grinding. An apparatus, comprising a plurality of grinding units, and means for installing the grinding units beside the crankshaft to move them closer to or farther from the crankshaft, The grinding unit includes a frame, a grinding belt having a grinding surface on one side and a back surface on the other side, and further, an endless and flexible abrasive belt, and the entire belt is opposite to each crankpin journal in each frame. And a means for moving each belt together with its frame independently of other belts and frames, with the grinding surface facing each crankpin journal, and substantially perpendicular to the crankshaft. Means for linearly driving the belt along a different path, and while the crankshaft is rotating, the grinding unit is moved independently of each other so as to move toward and away from the crankshaft, and the grinding surface of the belt. The crankshaft of 360
Means for contacting and grinding the crankpin journal over the full 360 ° range of rotation, and a grinding belt mounted on each frame to the crankpin journal over the full 360 ° range of rotation of the crankshaft. A backup member is in contact with the back surface of the grinding belt at the point of contact, and the distance between the pair of arms is such that the belt and the backup member protrude between the arms and the crankshaft rotates 360 °. Sometimes the crankpin journal is defined to be large enough to grind the entire 360 ° circumferential surface, and the backup member in each frame has a roller that is substantially parallel to the crankshaft. It is designed to rotate around a unique center line, and its periphery is on the back of the polishing belt installed on the frame. Grinding apparatus of the crank pin journal, characterized in that it is configured to. 2. The crankpin journal grinding device according to claim 1, wherein each of said rollers is configured to be rotatable. 3. The roller is configured to move together with the frame to which the roller is attached so that the center of rotation of each roller is substantially transverse to the longitudinal centerline of the crankshaft. The crankpin journal grinding device according to claim 1. 4. The diameter of each roller is greater than the diameter of the circle drawn by the crankpin journal contacted by the belt supported by the roller.
Grinding device for the described crankpin journal. 5. The portion of each roller facing the crankshaft constitutes a tip portion, and the belt mounting means includes means for hanging the belt over a sufficient arc portion of the tip portion of the roller. 5. The grinding of a crankpin journal according to claim 4, wherein the belt is configured to be supported by a roller while the belt is in contact with the crankpin journal while the crankshaft rotates 360 degrees. apparatus. 6. Each roller is rotatable and
6. The crankpin journal grinding device according to claim 5, wherein the grinding device is in contact with the belt in a substantially frictionless state.