JPS58143904A - Machining device for crank journal - Google Patents

Abstract

PURPOSE:To perform high precision working by preventing oscillation that appears when the center hole on the side of the reference surface of a crank shaft is supported by the tailstock center to work the journal portion. CONSTITUTION:The crankshaft W is positioned on the basis of the center. After the crankshaft is clamped by the chuck 4, the crankshaft W is pushed by the tailstock center 9 toward the chuck 4. Therefore, though the crankshaft W is bent, the center 9 follows the displacement of the center hole to keep supporting rigidity always with a constant supporting force and, accordingly, to release the oscillation in time of a cutting process. The center ram 4 can position the crankshaft exactly at the reference position thereby the axial direction of the crankshaft is positioned correctly.

Description

[Detailed description of the invention] The center hole on the reference surface side of the crankshaft is located at the tailstock center 1-A,
The purpose of this is to prevent chatter when machining the journal part by supporting it with l, and to perform high-precision machining.

As shown in Fig. 1, the turning process for the journal part of the crankshaft is generally performed in two steps: the journal part aJAJ on the rear side A and the journal part IJ~2JY on the front side B. Journal part 3J to 5J of A
When machining, the front side B is clamped with the chuck 4, and the center hole of the rear side A is supported and machined with the Shinshindai center S1. Also, the front side jA journal part IJ~
When machining 2J, the rear side A is chucked and the front side B is supported in the center and machined.

Normally, as the axial reference plane of the crankshaft W, the end face on the rear side A is the reference plane C, and the journal parts 3J to 5J to the rear side are
During machining, the crankshaft W is positioned with reference to the center hole on the rear side. Therefore, the Shinjindai center S1 becomes the reference center, and the center is fixed at the reference position, and the spring center S2 with built-in crankshaft WY chuck 4 is attached to it.
2. Clamped after positioning by pressing -.

By clamping such a chuck, the pressing force of the spring center built into the chuck is restrained by the clamp part and the pressing action is killed. Therefore, when the crankshaft is bent due to cutting resistance, the tailstock center S1 and the center hole of the rear side A are It was discovered that a gap was created between the two, reducing the supporting rigidity of the crankshaft and causing chatter.

The present invention eliminates the conventional problems identified above, and its feature is that even if the crankshaft is bent due to cutting resistance, the tailstock center follows the displacement of the center hole and maintains a constant supporting force. It is something that has been set.

Embodiments of the present invention will be described below with reference to FIGS. 2 and 5.

In FIG. 2, 1 is a bed. A headstock 2 and a tailstock 7 are installed on the bed 1, and the headstock 2 has a main spindle 3.
It has a chuck 4 fixed to this main shaft 3, and a spring center S2 is provided in the chuck 4. 5
is a drive motor, and 6 is a pulley. The tailstock 7 has a center ram 8 and a center 9 that can move forward and backward. Headstock 1
A slide base 10 is provided on the bed 1 between the tailstock 7 and the tailstock 7, and a tool slide 11 is attached to this. W indicates a crankshaft supported by the center 9 on the tailstock 7 side and the spring center S2 of the chuck 4011I, and clamped by the chuck 4.

In the present invention, the configuration of the tailstock 7 side is as shown in FIGS. 3 to 5. That is, the center ram 8 is provided on the shinshindai main body 12 so as to be able to freely slide forward and backward in the axial direction. A center 9 is rotatably held at the tip of the center ram 8 via a center holding shaft 13. Reference numeral 14 denotes a centering rod fitted to the center holding shaft 13, one end of which is fixed to the center stand main body 12, and inserted through the center ram 8 and the axes of the center holding shaft 13. By moving the center ram 8 further backward from the normal retreat position, the end of the centering rod 14 pushes out the center 9 due to the relative movement between the center ram 8 and the centering rod 14.

An axially long relief recess 15 is formed in a part of the outer periphery of the upper surface of the center ram 8, and an inclined protrusion 16 that intersects with the axis of the center ram 8 is protruded from approximately the center of the relief recess 15. Further, a guide member 19 having a guide surface in a direction perpendicular to the axis of the central ram 8 is provided within the escape recess 15 and fixed to the Shinshindai main body 12. The sliding member 17 is guided by this guide member 19. The sliding member 17 has an inclined cam 18 that engages with the inclined projection 16.
is provided. This sliding member 17 is connected to a two-stage cylinder support.

As shown in Fig. 5, the structure of the two-stage cylinder press consists of a small diameter cylinder n and a large diameter cylinder. equipped. The first piston field is integrated with a piston rod 21 connected to the sliding member 17, a small diameter cylinder n, a second piston δ, and a second piston part,
Cylindrical shaft δ protruding outward from the rear end of the large diameter cylinder 24
It is connected to a small diameter rondo that runs vertically through α. A stopper 27 is attached to the outer end of the small-diameter rod so that its position can be adjusted freely, the stopper 27 coming into contact with the end surface of the cylinder axis.

Next, the operation of the above configuration will be explained. In FIG. 4, the α position of the center 9 is the rearward end position! This is the position where the crankshaft W is attached and detached.

Further, the b position is a reference position where the center 9 engages with the center hole on the reference surface C side of the crankshaft W, and the C position is the forward end position where the center 9 moves forward and backward with the required follow-up stroke Ll since it is the reference position.

Control of each of the positions α, b, and c is obtained as follows. First, the rearward end position α is such that the first piston blade of the two-stage cylinder is at the rearward end indicated by the imaginary line, and the second
As shown, the piston 5 is at the rearward end position. Therefore, the sliding member 17 connected by the piston rod 21 is located at the retreating end α1, and the center ram 8 is moved backward by the relationship between the inclined cam 18 and the inclined protrusion 16, so that the center 9 is located at the retreating end position ia. Let me. At this rearward end position α of the center 9, the crankshaft W is attached and detached as described above.

Next, the reference position that engages with the center hole of the crankshaft W is
The second piston 5 is located at the backward end, and only the first piston holder moves forward and stops when the stopper n at the end of the small diameter rod 26 comes into contact with the repelling end surface of the cylinder shaft. The forward stop position of the first piston η is not the full stroke up to the end of the small diameter cylinder 22, but has a gap 12y between it and the front end of the small diameter cylinder n. Based on this forward movement of the first piston n, the sliding member 1
7 is located at the forward position h1, and the inclined cam 18 and inclined protrusion 1
6, the center ram 8 is moved forward and the center 9 is located at the reference position. At this reference position of the center 9, the crankshaft W is
is positioned and clamped by the chuck 4.

After the crankshaft W is clamped, the second piston 5Z moves to the forward end. By this movement of the second piston 5 to the forward end, the cylinder shaft also moves forward, and the end face of the cylinder shaft and the stopper 2
A gap is formed between 7 and 7. Therefore, the first piston 23 whose forward movement has been restrained by the stopper 27 until now is released, and has a pressing force in the forward direction between the gap 120. Applying a forward pressing force to the first piston 23 means that the sliding part 17 is pressed in the forward direction, and the inclined cam 18 and the inclined protrusion 16 push the center ram 8 in the forward direction. ing. Therefore, when the crankshaft W is bent due to cutting resistance during machining of the journal portions 3J-5J of the crankshaft W and the center hole is displaced, the center 9 follows the displacement of the center hole and returns to the reference position, so that the center 9 moves to the forward end position. It is displaced by the follow-up stroke 1 of C and maintains a constant supporting force '1''. Note that C1 is the forward end position of the sliding member [7].

As described above, according to the device of the present invention, the crankshaft is positioned based on the center, and after clamping by the chuck, the crankshaft is pressed toward the chuck at the center of the tailstock. Even if the crankshaft is bent, the center follows the displacement of the center hole, allowing a constant supporting force to be maintained and supporting rigidity to be maintained, eliminating chatter during cutting.

Furthermore, since the center ram can be correctly positioned at the reference position, the crankshaft can be accurately positioned in the axial direction. Therefore, the crankshaft journal part has the effect of being able to be machined with higher precision than in the past.

[Brief explanation of the drawing]

Fig. 1 is an explanatory diagram of the conventionally common center support and clamp in crank journal machining, Fig. 2 is a front view of the entire device of the present invention, and Fig. 3 is a cross section of the main parts of the device of the present invention. 4 Figure 11 line sectional view, Figure 4 is a plan view, Figure 5
The figure is a sectional view taken along the line 11 in FIG. 4. 1 *e* bed, 200. Headstock, 31. . Main spindle, 4...Chuck, 7...Tailstock, 8...-Center ram, 9...Center, 15...-Escape recess, 16
... Inclined projection, 17 ... Sliding member, 18 ... Inclined cam, 19 ... Guide member, locking member ... Two-stage cylinder, 2
1・Φ・Piston rod, n...Small diameter cylinder, long・
・・First piston, 24+1・・Large diameter cylinder 251
1...Second piston, j...Cylinder shaft,...Small diameter rod, n...Stopper.

Claims (1)

[Claims] It has a center support that supports the center hole on the reference surface side of the crankshaft, a positioning pressing member that suppresses the crankshaft in the axial direction at the center of the support, and a chuck that holds and clamps the opposite side of the crankshaft. In a crank journal machining device equipped with a headstock, a center ram that is guided to the center ram main body so as to be able to move forward and backward and has a center at one end;
A crank journal machining device comprising: positioning means for positioning the center ram at a forward reference position; and pressing means for releasing the positioning means after clamping the chuck and pressing the center ram in the forward direction.