JPH03163B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a chuck that indexably holds a crankshaft workpiece having a plurality of crank pin portions having different phases.

Conventionally, in a processing device where the workpiece is a crankshaft and the crank pin portion of the crankshaft is machined, a chuck attached to the front surface of the spindle face plate aligns the axis of the journal portion of the crankshaft with the axis of the spindle face plate. It is held eccentric to the
An index plate is rotatably provided concentrically with the axis of the journal portion, and by rotating the index plate, the phase is divided so that the axis of the crank pin portion coincides with the axis of the main shaft face plate. It is configured so that it can be taken out freely.

Furthermore, since the distance (the amount of eccentricity) between the two axes of the crankshaft journal part and crankpin part varies depending on the type of crankshaft, by moving the index plate in the radial direction of the main shaft face plate, This corresponds to changes in the amount of eccentricity.

However, in the conventional chucks as described above, changes in the amount of eccentricity were accommodated by moving the chuck body in the radial direction with respect to the main shaft face plate, which resulted in the heavy object moving in the radial direction. , there was a drawback that the amount of change in the center of gravity was large and rotational vibration was likely to occur, and therefore the processing accuracy was poor.

In addition, when machining the crank pin portion of a crankshaft as a workpiece, there are two methods: machining the outer peripheral surface of the pin portion and machining the fillet portion of the pin portion (this refers to machining band-shaped grooves on both sides of the pin portion). In particular, in the latter case, high surface roughness is required and high-speed cutting is required, so it is necessary to rotate the spindle face plate at high speed. For this reason, in those in which the chuck body is moved in the radial direction, the change in the center of gravity with respect to the change in eccentricity is large, so it is difficult to improve the surface roughness when machining the fillet portion.

Therefore, the present invention has been made to solve the above-mentioned conventional drawbacks, and its gist is to fix the chuck body to the main shaft face plate, and to attach the spline shaft and index plate to the chuck body in the radial direction. The journal holder and spacer can be replaced according to the amount of eccentricity of the crankshaft, and can correspond to the amount of eccentricity of the spline shaft without moving the heavy object in the radial direction. It is intended to improve the machining accuracy, and also to improve the machining accuracy of the fillet portion of the crank pin.

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

FIGS. 1 and 2 are a front view and a sectional view taken along the - line, respectively, showing an embodiment of the present invention. In the figures, reference numeral 1 designates a main shaft face plate which is rotatable around its axis O. A chuck body 2 is fixed to the main shaft face plate 1 with bolts 3. Further, a rotating shaft 4 is mounted at the center of the face plate 1 so as to be rotatable relative to the face plate 1. This rotating shaft 4 is a shaft that transmits a rotational force for performing phase indexing as described below, and during indexing, the axis is adjusted to e through a universal joint 5 (the one shown is an Oldham joint). The rotational force is transmitted to the spline shaft 6 which is separated by the same amount.

The spline shaft 6 is connected to the index plate 7.
The plate 7 has engagement grooves 7a ₁ , 7 at three equal parts on the outer circumference as shown in
a ₂ and 7a ₃ are formed, and the notch 8a of the notch member 8 engages with the groove 7a ₁ of these grooves to prevent the index plate 7 from rotating in the counterclockwise direction. Clockwise rotation is inhibited by the tip of the piston member 9 shown in FIG.

The spline shaft 6 is fitted into a hole 11a at the rear of the sliding member 11.
is slidable relative to the chuck body 2 in the vertical direction (radial direction of the chuck body 2) in FIGS. 2 and 3, so the spline shaft 6 and index plate 7 also move integrally in the radial direction can be done. In other words, the distance e between the axes can be changed.

The notch member 8 is provided inside the sliding member 11.
is attached, and the notch member 8 is pressed by one end of the spring 12 in the direction of engagement with the groove _7a1 . The other end of the spring 12 is engaged with a spring receiving member 13, and the receiving member 13 is fixed to the sliding member 11 with a bolt 14 (FIG. 3), with a bolt 15 attached to the female thread at the end. is fixed to the chuck main body 2 by a nut 19 via a screwed lid 16, a spacer 17, and a holding member 18, so that the sliding member 11 is prevented from sliding in the illustrated state. Therefore, if the nut 19 is loosened, the spacer 17 is removed, and another separately prepared spacer with a different thickness is attached, the sliding member 11
The mounting position of the spline shaft 6, which moves integrally with the sliding member 11, can be changed in the radial direction.
It is possible to change the

At the front of the chuck body 2, a journal holder 21 and a clamp arm 22 are mounted for fixedly holding a workpiece W (that is, a crankshaft). The journal holder 21 is detachably fixed to the chuck body 2, and the clamp arm 22
is pivotally connected to the chuck body 2 by a shaft 23 as shown in FIG. 4, so that it can swing about the axis of the shaft 23 in the directions of arrows a and a' in FIG. This swinging is achieved by engaging the rack portion 24a of the rack piston 24 with the pinion portion 23a formed on the shaft body 23, and reciprocating the rack piston 24 in the direction perpendicular to the plane of the paper in FIG. 4 (in the axial direction). I'll go with it. Note that the reference numeral 25 is a metal supporting the shaft body 23.

The above-described swinging of the clamp arm 22 is performed when the workpiece W is attached or detached, and FIG. 1 shows the workpiece W set in a state where it can be processed.
When the workpiece W is to be attached to the outside upon completion of machining, it is swung in the direction a.

The configuration of the tip of the clamp arm 22 with the workpiece W set thereon is as shown in FIG. That is, a slope 22b is formed in a hole 22a drilled in the clamp arm 22, and this slope 22
The slope 26a at the tip of the piston member 26 comes into contact with the tip of the piston member 26, and pressure fluid is sent to the cylinder 27 provided in the chuck body 2, thereby pushing the piston member 26 in the direction of the slope 22b.As a result, the clamp arm 22 is pressed downward in FIG. 5, and as shown in FIGS. 1 and 2, the clamp arm 2
The journal portion Wj of the workpiece W being pressed by the journal holder 21 is firmly clamped together with the journal holder 21. In addition, the code 28 is the chuck body 2.
It is a holding member fixed to.

When clamping such a workpiece W, a reference hole is provided in the end face of the workpiece W, and the reference hole is inserted into a dowel pin 32 fixed to the index plate 7 via a cover member 31 (FIG. 2). The holes are first engaged and then the clamping operation is performed.
The reason why the workpiece W is engaged with the reference hole is that the axis of the crankpin part Wp of the workpiece W is completely aligned with the axis O of the face plate 1 described above, and the crankpin part Wp of the workpiece W is to be machined. This is to ensure that Wp rotates correctly around its axis.

When it is desired to disengage the dowel pin 32 from the reference hole, that is, when it is desired to remove the workpiece W after machining is complete, the dowel pin 32 is moved to the right in FIG. 2. In this case, the locking member 33, which is engaged with the convex portion 7b of the index plate 7 through the concave portion 33a, is moved rearward in the O-axis direction (in the direction of the arrow b). The locking member 33 is integrally fixed to the piston member 34 at a portion not shown.
By supplying and discharging pressure fluid to the left and right chambers of the piston member 34, the dowel pin 32 can be engaged and disengaged.

Here, the locking member 33 and the piston member 34 constitute a knock pin moving means in the present invention.

Next, we will discuss the effect.

Workpiece (crankshaft) W as shown in Figures 1 and 2
When the spindle face plate 1 is rotated around its axis O with the main shaft set, the chuck body 2, index plate 7, sliding member 11, clamp arm 22,
The workpiece W and the like rotate integrally with the face plate 1 around the O axis. As mentioned above, the journal part of the workpiece W
The distance (eccentricity) e' between the axes of Wj and the crank pin part Wp is designed to match the distance e from the axis of the spline shaft 6 to the O axis (that is,
Spacer 17 and journal holder 2 as described later
1), the workpiece W rotates around the axis of the crank pin portion Wp.

Then, the crank pin part Wp shown in Fig. 2 is machined, and in the case of this embodiment, there are three pin parts Wp (in other words, it is a crankshaft for a three-cylinder engine), and the phase is changed by 120 degrees. Since the pin part Wp is in a shifted position, when machining the next adjacent pin part Wp, rotate the index plate 7 shown in Figure 3 by 120 degrees clockwise and engage the notch 8a with the groove _7a2. Match. This process will remove the adjacent unprocessed pin area.
The axis of Wp coincides with the O axis, and the face plate 1
By rotating the unprocessed pin portion Wp, the unprocessed pin portion Wp can be processed. When machining the remaining unmachined pin portion Wp, the index plate 7 may be further rotated by 120 degrees to engage the notch 8a with the groove _7a3 . During the processing, the clamp arm 22
Needless to say, the locking member 33 should be positioned in the state shown in the second figure and firmly clamped before processing.

After the machining of the three clamp pin parts Wp is completed, the clamp arm 22 is swung in the direction a, and the locking member 33 (Fig. 2) is moved in the direction b, thereby moving the knock pin 32 in the same direction. , After that, the processed workpiece W is carried out to the outside.

Next, even if the workpiece is the same crankshaft, the amount of eccentricity between the crank pin part Wp and the journal part Wj is
Since e' changes depending on the type of crankshaft, for example, the work will be described when setting the pin portion Wp in three locations and only e' has changed. In this case, with the workpiece W shown in FIG. 2 removed, the spacer 17 and journal holder 21 are replaced with separately prepared ones. In other words, since the type of crankshaft is known in advance, the spacer and journal holder are made according to those dimensions. If the spacer 17 is changed to a thicker one, for example, the receiving member 1
3. The sliding member 11 and the spline shaft 6 are pushed down in FIG. 2, and the distance e between the shafts increases and is set to match the new workpiece W.

In the above description of the embodiment, it is assumed that the number of crank pin parts Wp of the workpiece W is three, but for example, in the case of a crankshaft for a four-cylinder engine, the number of pin parts Wp is four. Since the pin portions Wp are positioned 180° out of phase, it is only necessary to replace the index plate 7 with a separately prepared one (having four grooves).

As described above, the present invention provides a chuck main body fixed to a main shaft face plate that rotates around the axis, a sliding member provided slidably in the radial direction with respect to the chuck main body, and a chuck that fits into the sliding member. a spline shaft whose axial center is offset from the axial center of the main shaft face plate and which is rotationally driven via a universal joint; and an outer peripheral portion which is mounted within the sliding member so as to rotate integrally with the spline shaft. The index plate has engagement grooves corresponding to the number of crank pin parts of the crankshaft that is the workpiece, and a knob pin for moving in the axial direction a crankshaft positioning knob pin fixed to the end face of the index plate. a moving means, a journal holder that is detachably fixed to the end face of the chuck body and holds the journal portion of the crankshaft on the axis of the spline shaft, and a receiving member that is coupled to the chuck body and the sliding member. a spacer detachably attached between the spacer, a bolt that connects the receiving member to the chuck body via the spacer, and a bolt that is held by the chuck body and firmly holds the journal part together with the journal holder and the workpiece. The structure consists of a clamp arm that swings to the open state when removed, so when dealing with changes in the eccentricity of the crankshaft that is the workpiece, heavy objects attached to the chuck body can be moved in the radial direction of the chuck body. There is no need to move the spindle face plate, and therefore, rotational vibration due to rotation of the spindle face plate is less likely to occur, so machining accuracy can be improved. Furthermore, when machining the fillet portion of the crankshaft crankpin portion, it is necessary to rotate the main shaft face plate at a particularly high speed, and since the rotational vibration is small, it can be expected that the machining accuracy will be improved even in such machining.

[Brief explanation of the drawing]

Figure 1 is a front view showing one embodiment of the present invention, Figure 2 is a front view showing one embodiment of the present invention;
The figure is a sectional view taken along the - line in Figure 1, and Figure 3 is a cross-sectional view of Figure 2.
A sectional view taken along the - line in the figure, Fig. 4 is a - of Fig. 1.
FIG. 5 is a sectional view taken along the - line in FIG. 1. DESCRIPTION OF SYMBOLS 1...Main shaft face plate, 2...chuck body, 6...spline shaft, 7...index plate, 11...sliding body, 17...spacer, 21...journal holder,
32... Knock pin, 33... Locking member.

Claims (1)

[Claims] 1. A chuck body fixed to a main shaft face plate that rotates around its axis, a sliding member provided so as to be slidable in the radial direction with respect to the chuck body, and a chuck body fitted with the sliding member so that its axis is A spline shaft is located at a position offset from the axis of the main shaft face plate and is rotationally driven via a universal joint, and a crank, which is a workpiece, is attached to the outer periphery of the spline shaft and is mounted within the sliding member so as to rotate together with the spline shaft. an index plate having engagement grooves corresponding to the number of crank pin portions of the shaft; a knot pin moving means for moving in the axial direction a crankshaft positioning knob pin fixed to an end surface of the index plate; A journal holder that is detachably fixed to an end face of the main body and holds the journal part of the crankshaft on the axis of the spline shaft, and a receiving member that is coupled to the chuck main body and the sliding member. a spacer attached to the chuck body; a bolt that connects the receiving member to the chuck body via the spacer;
A chuck for holding a crankshaft, comprising a clamp arm that is held by the chuck body, firmly holds the journal part together with the journal holder, and slides to an open state when a workpiece is removed.