JPS582772B2 - mechanical chuck - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention, for example in a crankshaft crankpin turning machine, takes a workpiece having an eccentric part in and out of the chuck in the radial direction, and moves the workpiece into a journal →.
This invention relates to a mechanical chuck that is firmly gripped by a support base provided on the chuck body and two gripping claws fitted into radial grooves of the chuck body.

In the present invention, a chuck body is provided with a support base for supporting a workpiece, and gripping claws each having a rack and a wedge groove are fitted into two radial grooves of the chuck body, and the gripping claws are fitted into the hollow chamber of the chuck body. Two change nuts having twisted grooves are connected to a first pressing plate which is internally connected to a compound rotary cylinder and moves in the axial direction, so that the change nuts can be slid by a predetermined amount only in the axial direction, and this change The helical grooves of the nut are screwed into the threads of two pinion shafts that are axially supported in the chuck body, the pinions at the front of the pinion shafts are screwed into the racks of the gripping claws, and then the chuck body The rear ends of the two wedge shafts that are fitted into the chuck body and slide only in the axial direction are fixed to a second pressing plate that is installed in the hollow chamber of the chuck body and moves in the axial direction in connection with the rotating cylinder, The tip wedge portion of the wedge shaft is configured to engage with and disengage from the wedge grooves of the gripping claws, and the gripping claws are opened and closed to move the workpiece in and out of the chuck in the radial direction. 1st by means of a pinion, rack, etc. that simply slides the part largely.
The opening/closing means is separated from the opening/closing means by the second opening/closing means using a strong wedge action to firmly grip the workpiece, and the opening/closing stroke of the gripping jaws can be increased, thereby chucking the workpiece. The workpiece can be put in and taken out in the radial direction, making it easy to attach and detach, and the workpiece with an eccentric part that requires strong holding force can be reliably and firmly held in place by two gripping claws and a support base that apply a wedge force. It is an object of the present invention to provide a mechanical chuck that can be firmly gripped.Hereinafter, the present invention will be explained in detail based on an embodiment shown in the drawings.

Figures 1 to 3 show the state in which the journal part (grip part) of a crankshaft used as a workpiece is clamped. 1 is the chuck body of the mechanical chuck, and its rear part (
The left side in FIG. 1 (hereinafter the left side in FIG. 1 will be referred to as the rear side) is fastened to the spindle 2 of the machine tool with bolts 3.

A support base for supporting the crankshaft W is fastened to the front end of the chuck body 1 (the right side in FIG. 1, hereinafter the right side in FIG. 1 will be referred to as the front side) with bolts 5. , supports a journal portion J that is offset by a predetermined amount from the crank pin P so that the axis of the crank pin P to be machined can coincide with the rotation center of the spindle 2.

A drop-in groove 6 is formed in the chuck body 1 above the support base 4 in FIG. 2 to allow the crankshaft W to be carried onto the support base 4.

As shown in FIG. 2, on both sides of this drop-in groove 6, radial grooves 7 are bored in the chuck main body 1 and are centered on the axis J of the journal part on the support base 4. Gripping claws 8 for gripping the journal portion J are slidably fitted in the respective parts.

The gripping claw 8 is provided with a rack 9 and a wedge groove 10 as shown in FIGS. 4 and 5.

On the other hand, a hollow chamber 11 as shown in FIG. 1 is formed in the chuck body 1.

A first press plate 12 whose shaft front part is loosely fitted into the chuck body 1 is installed in the hollow chamber 11, and the first press plate 12 is prevented from sliding forward by the stopper wall 1A of the chuck body 1. It is now possible to do so.

Although not shown, the shaft rear portion of the first press plate 12 is connected to a first piston rod of a rotating cylinder provided at the rear of the spindle 2 via a connecting rod 13.

The rotary cylinder is of a composite type and has two pistons that operate independently of each other and first and second piston ronds connected to the pistons.

Change nuts 14, as shown in FIG. , can only be slid in the axial direction.

The change nut 14 has a loose fitting surface 16 with the first pressing plate 12 that is longer than the thickness of the pressing plate 12 by a predetermined amount, and can come into contact with the first pressing plate 12 before and after the loose fitting surface 16. A contact surface 17,18 is formed in each case.

That is, the change nut 14 is connected to the first suppression plate 12 so as to be slidable by a predetermined amount only in the axial direction.

A through hole 19 is bored in the axial center of the change nut 14, and a helical groove 20 is threaded therein.

A pinion shaft 21 is fitted into this penetration hole 19,
Both ends thereof are rotatably supported by the chuck body 1 via steel balls 22, and a threaded portion 23 formed on the pinion shaft 21 is connected to the helical groove 20 of the change nut 14.
are screwed together.

A pinion 24 is carved in the front part of the pinion shaft 21, and this pinion 24 meshes with the rack 9 of the gripping pawl 8.

The left and right sides of the first pressing plate 12 (left and right in FIG. 2)
On both sides, as shown in FIG. 3, a secondary wedge shaft 26 with a stem 25 formed on the front side is loosely fitted into the chuck body 1 with a key 27 so as to be slidable only in the axial direction, and the secondary wedge shaft 26 and An elastic spring 28 is sealed between the first pressing plate 12 and the first pressing plate 12 .

Grip both sides of the balance weight part B of the crankshaft W with the elasticity of the elastic spring 28 in a direction perpendicular to this secondary wedge shaft 26 (left-right direction in FIG. 2), and align the crank pin part P with the center of the spindle 2. A sub-gripping claw 30 for angular positioning is slidably fitted into the chuck body 1.

A wedge groove 31 that engages with the free portion 25 of the auxiliary wedge shaft 26 is formed in the auxiliary gripping pawl 30, and the auxiliary gripping pawl 30 slides due to the engagement between the wedge portion 25 and the wedge groove 31. It is configured.

(See Figure 6) Connecting pipe 3 is connected to the second piston rond of the rotating cylinder.
2 are connected to each other, and the hollow shaft of a second pressing plate 33 installed in the hollow chamber 11 is screwed to the connecting pipe 32, and the hollow shaft of the second pressing plate 3, 3 is connected to the first pressing plate. It is slidably fitted onto the shaft of No. 12.

As shown in FIG. 3, the rear end portions of wedge shafts 34 are fixed to the left and right sides of the second pressing plate 33, and the wedge shafts 34 are loosely fitted into the chuck body 1, and are rotated in the axial direction by a key 35. It is possible to slide only.

A tip wedge portion 36 is formed on the front side of the wedge shaft 34 and is capable of engaging and disengaging with the wedge groove 10 of the gripping claw 8 (see FIGS. 4 and 5). The claw 8 is configured to slide.

The amount of sliding movement of the wedge shaft 34 after engaging the wedge groove 10 of the gripping claw 8 until the gripping claw 8 comes into contact with the journal portion J is the amount of movement in which the change nut 14 moves within the predetermined amount. It corresponds to the quantity.

Next, the operation of the mechanical chuck described above will be explained.

When the crankshaft W is carried in from above through the drop-in groove 6 of the chuck body 1 and the journal portion J of the crankshaft W is placed on the support base 4, the first piston rond of the rotating cylinder is moved forward. movement, causing the first pressing plate 12 to slide forward via the connecting rod 13.

Pushed by this first pressing plate 12, both the left and right change nuts 14 move forward, the pinion shaft 21 screwed into the change nut 14 rotates, and the pinion 24 and rack 9
Due to the engagement, the left and right gripping claws 8 slide in the radial groove 7 toward the journal portion J from the opening position shown by the imaginary line E in FIG.

When the first pressing plate 12 comes into contact with the stopper wall 1A of the chuck body 1 and stops, the gripping claws 8 stop slightly before contacting the journal portion J, and the wedge grooves 1 of the gripping claws 8 stop.
0 and the tip wedge portion 36 of the wedge shaft 34 are in a state where they can be engaged as shown in FIG.

On the other hand, at the same time as the change nut 14 moves forward, the left and right secondary wedge shafts 26 are slid forward via the elastic springs 28 by the first pressing plate 12, and the wedge portion 25 of the secondary wedge shaft 26 and the secondary gripping pawl 30 are moved forward. By engaging with the wedge groove 31, the sub gripping claw 30 slides,
Both sides of the balance weight part B of the crankshaft W are held elastically to align the axis of the crank pin part P with the axis of the spindle 2.

In this embodiment, the left and right sub-gripping claws 30 are configured to operate simultaneously, but it is also possible to fix one of them at a mounting reference position and press the reference surface from one side. reach

Next, the second piston rod of the rotary cylinder moves forward, and both the left and right wedge shafts 34 slide forward via the second pressing plate 33, and the tip wedge portion 36 of the wedge shaft 34 engages the gripping claw 8. The gripping pawl 8, which has been engaged with the wedge groove 10 of the journal part J and stopped at a position slightly in front of the journal part J, further slides toward the journal part J and firmly grips the journal part J by the wedge action. do.

In this case, as the gripping claw 8 further slides, the pinion shaft 21 is engaged with the rack 9 and the pinion 24.
is rotated, and the change nut 14 is rotated so that its contact surface 17 is connected to the first suppression plate 1 by the threaded engagement of the threaded portion 23 and the twisted groove 20.
2 and slides further forward, resulting in the state shown in FIG.

As described above, the left and right gripping claws 8 move straight to grip the journal portion J on the support base 4, and also slide greatly due to the action of the rack 9 and the pinion 24, and the wedge groove 10 and the tip wedge portion 3
The journal part J is firmly gripped by the wedge action of 6.

Then, the journal portion J is securely gripped by both gripping claws 8 at the center of both gripping claws 8.

After the journal portion J is gripped by the gripping claws 8 in this manner, the crank pin portion P of the crankshaft W is cut.

Thereafter, the operations are performed in the reverse order.

That is, when the second piston rond retreats, the gripping claw 8 is slightly separated from the journal portion J due to the action of the wedge shaft 34.
Next, when the first piston rod retreats, the grip part 8 is moved by the action of the change nut 14 and the pinion shaft 21.
At the same time, due to the action of the auxiliary wedge shaft 26, the auxiliary gripping pawl 30 also slides in the opposite direction and returns to its original state, and then the crankshaft W is carried out from the chuck body 1. be done.

As described above, the present invention provides the chuck body with a support base for supporting the workpiece, and also fits gripping claws each having a rack and a wedge groove into two radial grooves of the chuck body,
Two change nuts with twisted grooves are connected to the first press plate, which is installed in the hollow chamber of the chuck body and moves in the axial direction in connection with a compound rotary cylinder, so as to be able to slide by a predetermined amount only in the axial direction. Then, the helical grooves of this change nut are screwed into the threads of two pinion shafts that are axially supported in the chuck body, and the pinions at the front of the pinion shafts are respectively engaged with the racks of the gripping claws. Furthermore, the rear ends of the two wedge shafts that are fitted into the chuck body and slide only in the axial direction are connected to a second wedge shaft that is installed in the hollow chamber of the chuck body and moves in the axial direction in connection with the rotary cylinder. It is fixed to the pressing plate, and the tip of the wedge shaft is configured to engage and disengage from the wedge grooves of the gripping claws, so that opening and closing of the gripping claws can move the workpiece in and out of the chuck in the radial direction. The first opening/closing means using the above-mentioned pinion and rack, etc., which simply greatly slides the gripping claw, and the second opening/closing means using a strong wedge action to firmly grip the workpiece, are carried out separately, The opening/closing stroke of the gripping claws is increased, which allows the workpiece to be taken in and out of the chuck in the radial direction, making it easier to attach and remove the workpiece, and the crank has an eccentric part that requires strong gripping force. A workpiece, such as a shaft, can be reliably and firmly held in a predetermined position by the two gripping claws on which a wedge force acts and the support base.

Furthermore, as in the above embodiment, if the sub-gripping claws that operate synchronously with the gripping claws are used together, the workpiece can be automatically and reliably gripped at a fixed position, so that the workpiece can be easily gripped in a crankpin turning machine, etc. It is convenient for automation of chucking the eccentric part of the machine.

[Brief explanation of drawings]

The drawing shows an example of the mechanical chuck according to the present invention.
Fig. 1 is a longitudinal cross-sectional view of the mechanical chuck when holding a workpiece, Fig. 2 is a view of Fig. 1 viewed from direction A, and Fig. 3
The figure is a sectional view taken along line B-B in Figure 2, and Figure 4 is a cross-sectional view taken along line C-C in Figure 2.
5 is an explanatory view showing a state immediately before the wedge shaft and the gripping claw engage with each other, and FIG. 6 is a sectional view taken along the line DD in FIG. 2. 1... Chuck body, 4... Support base, 7... Radial groove,
8...Liberty claw, 9...Rack, 10...Wedge groove, 12...
First suppression plate, 14...Change nut, 20...Twisted groove, 21...Pinion shaft, 23...Threaded portion, 2
4... Pinion, 33... Second pressing plate, 34... Wedge shaft, 36... Tip wedge portion, W... Crankshaft (workpiece).

Claims (1)

[Claims] 1. A support base for supporting the workpiece is provided in the chuck body, and grasping claws each having a rack and a wedge groove are fitted into two radial grooves in the chuck body, and a compound Two change nuts having twist grooves are connected to a first press plate that moves in the axial direction in connection with a rotating cylinder of the mold so as to be able to slide by a predetermined amount only in the axial direction, and The grooves are respectively screwed into the threads of two pinion shafts that are axially supported in the chuck body, the pinions at the front of the pinion shafts are engaged with the racks of the gripping claws, and the pinions are then fitted into the chuck body. The rear ends of the two wedge shafts that slide only in the axial direction are fixed to a second pressing plate that is installed in the hollow part of the chuck body and moves in the axial direction in connection with the rotating cylinder, and the wedge shafts The mechanical chuck is configured such that the leading end wedge portions of the gripping claws engage with and disengage from the wedge grooves of the gripping claws.