JPS6119844Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a chuck device for machining a crank pin portion of a crankshaft.

In general, for machining a crank pin portion (hereinafter simply referred to as a pin portion) of a crankshaft, a chuck device is known that holds the journal portion eccentrically so that the pin portion to be machined coincides with the center of the main shaft. Such a chuck device includes a clamp device that presses and clamps the journal portion to a holder that holds the journal portion eccentrically. However, since the pin section machined with respect to the journal section clamped by this clamping device is offset in the axial direction and eccentric in the radial direction, the entire cutting force acts on the crank arm that connects the pin section and the journal section. Therefore, it was not possible to apply a cutting force greater than the rigidity of the crank arm, making heavy cutting difficult.

As a means to solve this problem, as shown in Japanese Patent Publication No. 47-18825, an auxiliary clamper is installed in the chuck body, which comes into contact with the tip of the crank arm that has the pin part to be machined, and supports the cutting resistance. There is one set up in By providing such an auxiliary clamper, it is possible to increase the support rigidity of the pin part more than the rigidity of the crank arm, making heavy cutting possible. However, the supporting action of such an auxiliary clamper provided on the chuck body side can be applied to When the crank arm adjacent to the pin part to be machined is located on the chuck body side, that is, when the holder that holds the journal part is eccentric to the clamp arm side with respect to the center of the main shaft, for example, in a 4-cylinder crankshaft. are the first and fourth pin parts
This is the case when processing P ₁ and P ₄ . The phase of the pin part is
When machining the second and third pin parts P ₂ and P ₃ that are 180 degrees apart, the adjacent crank arm will be located on the clamp arm side, and if the auxiliary clamper is installed on the chuck body side, the crank arm will be located on the clamp arm side. The tip of the arm could not be supported, making heavy cutting difficult.

In view of this, the present invention aims to improve machining efficiency by increasing the support rigidity of the crank pin part even when the pin part to be machined is located on the clamp arm side, making heavy cutting possible. .

Embodiments of the present invention will be described below with reference to the drawings.
The chuck device 10 shown in FIGS. 1 to 4 includes:
This is for machining the second and third crank pin portions P ₂ and P ₃ of a crankshaft for a four-cylinder engine. This chuck device 10 is designed to hold the left end of the crankshaft W, but since the chuck device that holds the right end of the crankshaft has almost the same structure, for convenience, we will refer to the left chuck device 10. explain. 11 is a headstock, 12 is a main shaft rotatably supported by the main spindle 11, 13 is a chuck body fixed to the end face of the main shaft 12, and this chuck body 13 holds a journal part J eccentrically with respect to the main shaft center O. A retainer 14 is fixed, and a clamp arm 15 for pressing the journal portion J is rotatably supported on a receiving surface 14a of the retainer 14 about a pivot shaft 16. The pivot shaft 16 is rotatably supported on the chuck body 13 via a bush 17 parallel to the axis of the main shaft, and is prevented from pivoting. The proximal end 15a of the clamp arm 15 is fixed to the end of the pivot 16 protruding from the tip of the chuck body by key engagement, and a pinion 18 is formed at the inner end thereof. This pinion 18 meshes with one end of a rack bar 19 that is slidably guided approximately in the radial direction of the chuck body 13, and the other end of this rack bar 19 is supported by a pinion 20 that is rotatably supported by the chuck body 13. It meshes with. A torsion spline shaft 21 is provided protruding from the pinion 20, and a spline sleeve 22 that fits into the torsion spline shaft 21 is attached to the key 20.
3, and is guided by a ram 24 inserted through the center of the main shaft 12 so as to be able to move only in the axial direction. One end of this spline sleeve 22 is connected to a movable body 2 that is slidably guided by a ram 24 as shown in FIG.
9, and this movable body 29 is pressed by a compression spring 25 whose one end is supported on the main shaft side. One end of the ram 24 is connected via a piston rod 28 to a piston 27 of a cylinder 26 formed concentrically with the main shaft 12. As shown in FIG. 5, an inclined surface 15c is formed on the upper surface of the tip portion 15b of the clamp arm 15.
A wedge body 30 having a tip end formed with an inclined surface 30a that fits snugly into the chuck body 13 is slidably guided by the chuck body 13, and the other end of this wedge body 30 is connected to a link 31 and a hinge pin as shown in FIG. It is connected to the ram 24 via 32 and 33. The clamp arm 1
5 and an inclined surface 15 formed at the tip of the wedge body 30
C and 30a are designed to apply a pressing force to press the clamp arm 15 toward the holder 14 as the wedge body 30 advances, and lock the clamped state of the clamp arm 15 by the wedge action.

Auxiliary clamper 35, which is a characteristic configuration of the present invention
is provided on this clamp arm 15,
It comes into contact with the tip of the crank arm of the pin part _P2 to be machined, and acts to support the rotational torque. This auxiliary clamper 35 is located at the center of the pin portion to be machined.
The front side 1 of the clamp arm 15 is arranged symmetrically with respect to the line L connecting the center of the journal part J and the center of the journal part J.
5d, and the four sides are restrained by the side guide member 36 and front presser plate 37 fixed thereto, and the line L
is slidably guided along. A pair of cylinders 38, 38 are provided on the rear side of the clamp arm 15.
A piston rod 40 of a piston 39 fitted into the cylinders 38, 38 passes through the clamp arm 15 and projects toward the auxiliary clamper 35. A wedge body 41 having inclined surfaces 41a and 41b which are inclined with respect to the cylinder center line and parallel to each other is formed at this projecting end. Inclined surfaces 40a and 40b are formed through the auxiliary clamper 35 and are fitted to the inclined surfaces 41a and 41b,
The auxiliary clamper 35 is moved forward and backward by the piston 39.
move forward and backward in orthogonal directions. A spring 45 is compressed and inserted between the piston 39 and the rear end wall of the cylinder 38 to apply a pressing force in the clamping direction. A pressure fluid introduction passage 46 communicating with the cylinder chamber 38a on the piston rod side is connected to the clamp arm 1.
5. The passage 48 of the main shaft 12 is communicated with the passage 47 formed in the shaft 16 and further formed in the sleeve 17 and the chuck body 13.
One end of the main shaft is connected to a fluid source via a fluid distributor (not shown) provided concentrically at the end of the main shaft.
When this fluid source is a compressed air source, the cylinder chamber 38b in which the spring 45 is housed may be provided with an atmosphere communication port 49. If a pressure oil supply source is used, communication passages may be provided in the clamp arm, pivot, chuck body, and main shaft, similar to the passages 47 and 48, and connected via a fluid distributor.

Next, the operation of the above configuration will be explained. The solid line state shown in the figure shows the clamped state of the crankshaft.
In order to unclamp this, pressure fluid is introduced into the cylinder chamber 38a on the piston rod side of the cylinder 38, which compresses the spring 45, causing the piston 39 to retreat, releasing the auxiliary clamper 35, and releasing the supported state of the crank arm. . When the piston 27 of the cylinder 26 on the rear end side of the main shaft 12 is moved backward, the wedge body 30 moves back together with the ram 24, releasing the locked state of the tip of the clamp arm 15. The movable body 29 does not move until this locked state is released and the movable body 29 and the inner end surface 24a of the ram 24 engage with each other, and no relative movement occurs between the spline sleeve 22 and the torsion spline shaft 21. Therefore, the clamp arm 15 is not rotated. Thereafter, when the inner end surface 24a of the ram 24 and the movable body 29 engage, the spline sleeve 22 moves backward together with the ram 24, so that a relative movement with the spline shaft 21 occurs.
Rotate the pinion 20. The rotation of the pinion 20 causes the pinion 18 and the pivot 16 to rotate via the rack bar 19, causing the clamp arm 15 to rotate in the unclamping direction, returning to the original position shown by the two-dot chain line in FIG. In this state, new and old workpieces are carried in and carried out. Piston 27 of cylinder 26
When the clamp arm 15 is moved forward, the clamp arm 15 rotates toward the holder 14 and presses the journal part by the reverse operation to that described above. Thereafter, the wedge body 30 locks the tip of the clamp arm 15. After locking, when the pressure fluid supplied to the cylinder chamber 38a of the cylinder 38 is brought to atmospheric pressure, the piston 39 moves forward due to the pressing force of the spring 45, so the auxiliary clamper 35 comes into contact with the tip of the crank arm, and the machining starts. The auxiliary clamper 35 supports the tip of the crank arm that is closest to the pin, and can bear most of the cutting resistance that occurs when machining the pin.

As described above, according to the present invention, since the auxiliary clamper is provided on the clamp arm side, it is possible to increase the support rigidity of the pin part when the pin part to be machined is located on the clamp arm side. In addition, the pressing force of the pair of auxiliary clampers can move forward and backward in the radial direction independently, so even if the contact surface of the crank arm is black crust, it can press evenly without uneven contact, deforming the crank arm, or changing the phase state. Provides torque support in the rotational direction without any change. Moreover, since the pressing force of this is in the same direction as the clamp arm, it also acts to increase the clamping force. Furthermore, since the support point of this auxiliary clamper 35 is close to the pin part _P2 which is machined in both the radial and axial directions with respect to the journal part that is pressed and supported by the holder 14 and the clamp arm 15, The pin support rigidity, which conventionally relied only on the rigidity of the crank arm, has been significantly increased, making heavier cutting possible and preventing reductions in machining errors due to workpiece deformation. In addition, although chatter tends to occur due to a decrease in cutting quality due to tool wear, there is an advantage that the occurrence of such chatter can be significantly suppressed.

[Brief explanation of the drawing]

The drawings show an embodiment of the present invention, in which FIG. 1 is a front view of the chuck device, FIG. 2 is a sectional view taken along the - line in FIG. 1, and FIG. 3 is a sectional view taken along the - line in FIG. 1. 4 are longitudinal cross-sectional views of the principal parts of the main shaft, and are views showing the operating mechanisms of the clamp arm and the wedge body. FIG. 5 is a cross-sectional view taken along the - arrow in FIG. 1. 12...Main shaft, 13...Chuck body, 14...
...Holder, 15...Clamp arm, 16...Pivot, 18, 20...Pinion, 19...Rack,
21...Torsion spline shaft, 22...Spline sleeve, 24...Ram, 30...Wedge body, 31...
... Link, 35 ... Auxiliary clamper, 38 ... Cylinder, 39 ... Piston, 41 ... Wedge body, 45 ...
…spring.

Claims (1)

[Claims for Utility Model Registration] (1) In a chuck device that eccentrically holds a journal portion in order to align the crankpin portion to be machined with the center of rotation of the main shaft, the journal portion adjacent to the crankpin portion to be machined is eccentrically held. A clamp arm that presses and clamps the journal part is provided on a retainer that is held centered, and a clamp arm is mounted on the clamp arm that abuts the tip of the crank arm connected to the crank pin part, restrains displacement in the circumferential direction, and clamps the journal part in the approximately radial direction. A chuck device comprising a pair of auxiliary clampers guided so as to be able to advance and retreat separately, and a drive means for moving the pair of auxiliary clampers individually in advance and retreat. (2) The chuck device according to claim 1, wherein the driving means includes a wedge body that engages with an end of the auxiliary clamper. (3) The pair of auxiliary clampers are arranged symmetrically across a line connecting the center of the crank pin portion and the center of the journal, and have contact surfaces that widen toward the tip portion as contact surfaces that come into contact with the tip portion of the clamp arm. A chuck device according to claim 1 of the utility model registration claim, comprising: