JPH0818166B2 - Compensating chuck - Google Patents

Description

Description: TECHNICAL FIELD The present application relates to an improvement of a compensating chuck (hereinafter referred to as a chuck), and more specifically, when a work is gripped, a center pin is clamped and held by fluid pressure for machining. This is intended to improve accuracy.

2. Description of the Related Art In the conventional chuck, the center pin is held by a conventional chuck, as shown in FIG. 6, in which a center pin 4 is slidably engaged with a holder 3 mounted on an axis of a chuck body, and a spring 5 is used. It is biased to the front side of the main body 2. Therefore, the gripping accuracy of the work in the chuck is the accuracy of the holding position of the center pin 4, that is, the center pin 4 when the work is gripped.
It depends on whether or not the axis of the center pin 4 and the axis of the chuck body 2 are completely aligned with each other. However, in order to slide the center pin 4 in the holder 3, a minimum necessary clearance is required. Providing this play has already become a cause of deterioration in gripping accuracy. In addition to this, in order to minimize the play, the inner peripheral surface of the holder 3 and the outer periphery of the center pin 4 must be finished with high precision, which requires a high processing technique and a long processing time. Further, in addition to the above, there is no other method than the replacement of the center pin 4 to maintain the initial accuracy during manufacturing due to wear caused by the sliding of the center pin 4.

Means for Solving the Problems The present application relates to an improvement of the above-mentioned conventional device, and in a compensating chuck in which a center pin is axially movable in the axial center of a chuck body and is biased forward, Attach the holder to the shaft core of
A gripping body with a center hole in the fitting part at the center of this holder,
The gripping body is fitted and fixed so that its axis coincides with the axis of the chuck body, and this gripping body is made of a material that is easily elastically deformable. A pressure-fluid storage groove that forms a closed chamber is formed between the fitting portion and the fitting portion, and the bottom of the storage groove is made thinner than the axial front and rear portion of the grip body, and the center hole of the grip body is provided with the center hole. A fluid conduit for connecting the pin so as to be movable in the axial direction and for connecting the storage groove and the pressurized fluid supply source is provided, and the thin portion is elastically deformed by the fluid pressure supplied to the storage groove to cause the center pin. It is characterized in that it is configured so as to hold the outer periphery while holding it.

Examples Hereinafter, the present application will be described in detail with reference to the drawings illustrating examples. The drawing shows a chuck 1 embodying the present invention, including a crank lever 6 pivotably supported on a chuck body 2, a jaw 7 mounted on the front surface of the crank lever 6, and a draw screw 8 connected to a rotary cylinder (not shown). The draw screw 9 connected to the draw screw 8 and the floating cam 10 loosely attached to the draw sleeve 9 are all well known, and operate in the same manner as in the prior art to release the work 11.

In the chuck 1 as described above, 12 is a gripping body made of a material such as spring steel or a resin molded product which easily causes elastic deformation,
A storage groove 13 for the pressurized fluid is formed on the outer peripheral surface of the axially intermediate portion. The wall pressure t of the bottom of the storage groove 13 is set to be as thin as possible in consideration of the pressure of the pressure fluid, which will be described in detail later, and the pressure of the pressure fluid is sensitive to the axis of the grip body 12. It is a thin portion that is configured to act. Reference numeral 3 is a holder attached to the axis of the chuck body 2, and the gripping body 12 is fitted and fixed to a fitting portion 14 provided on the holder 3 so that the axis of the holding body 12 coincides with the axis of the chuck body 2. Accordingly, the storage groove 13 provided in the grip body 12 has an inner peripheral surface 14 of the fitting portion 14.
It is closed at a and becomes a closed room. The center pin 4 is slidably fitted in the center hole of the gripping body 12 with a proper clearance, and is biased toward the front surface of the chuck 1 by a spring 5 as in the conventional case.

Reference numeral 15 denotes a pressure fluid pipe line drilled in the chuck body 2, one end of which opens to the reservoir groove 13 and the other end of which opens to the back side of the chuck body 2. This opening 15a Is connected to a supply of reduced pressure fluid for operating the draw screw 8 via a pressure fluid pipe provided on a spindle (not shown).

FIG. 1 shows the chuck 1 in a non-operating state. At this time, since the floating cam 10 is at the most advanced position, the center pin 4 is also projected to the open position of the jaw 7 and the pressure is not applied to the storage groove 13 described above. A fluid (hereinafter referred to as oil) is not supplied, and therefore, there is no guarantee that the center axes of the center pin 4 and the chuck body 2 are coincident with each other, and it is usual that they are not coincident with each other. Next, the work 11 is supplied automatically or manually, and the tip of the center pin 4 is fitted into the center hole 11a of the work 11. While pushing the center pin 4, the end face of the work 11 is brought into contact with the work locator 25 and positioned.

When the supply of the work 11 is completed, the rotary cylinder (not shown) is activated to pull the draw screw 8 and grip the work 11 as shown in FIG. 2. In this embodiment, the rotary cylinder is operated prior to the operation. Alternatively, substantially at the same time, that is, before gripping of the workpiece 11 by the jaws 7 is completed, high-pressure oil is supplied into the reservoir groove 13 from a hydraulic pump (not shown) that is a pressure fluid supply source. As described above, the gripping body 12 is fitted into the holder 3 as described above, and the entire circumference of the storage groove 13 is surrounded by the inner peripheral surface 14a of the fitting portion 14 to form a closed chamber. Since the holder 3 is firmly integrated with the chuck body 2, the pressure of the oil supplied to the storage groove 13 acts toward the axis of the gripping body 12 and elastically deforms the bottom portion having a thin meat pressure t. The center pin 4 loosely held together is clamped and held so that the play between the grip body 12 and the center pin 4 is absorbed to limit the chuck body 2 and the center axis of the center pin 4. The workpiece 11 is gripped with high accuracy by aligning the workpieces with an error close to zero. And this alignment operation is the same from the one relatively close to the initial accuracy to the one where wear progresses and the play becomes large, and the accuracy does not decrease due to some number of operating days, that is, with time. As described above, the pin 4 is held by the gripping body 12 that is under strong hydraulic pressure, so that even during heavy cutting, the pin 4 is not eccentric during processing and the accuracy is not reduced. When the work of the gripped work 11 is finished, the grip of the work 11 is released, the supply of the hydraulic pressure to the storage groove 13 is stopped, the center pin 4 is released, and the work 11 to be processed next is again processed by the same operation. Hold it. It should be noted that the supply and discharge of the hydraulic pressure to and from the storage groove 11 are appropriately selected and used from the hydraulic control mechanism which has been conventionally used, similarly to the operation of the draw screw 8, and the description thereof will be omitted.

Next, the embodiment shown in FIGS. 3 and 4 will be described. In the first embodiment, since the pressure of the hydraulic pump that operates the draw screw 8 is insufficient to the pressure that operates the gripping body 12, a separate hydraulic pump is provided and the gripping body is provided.
Although the pressure oil is supplied to 12, the present embodiment achieves the intended purpose by increasing the pressure oil for operating the draw screw 8 with the pressure increasing mechanism. Only parts different from the first embodiment will be described.

Reference numeral 16 is a pressure increasing mechanism, which is a piston chamber formed in the chuck body 2.
The floating piston 18 is sealed in 17 so that the piston chamber 18
The front side of the pressure chamber 19 is divided into the pressure increasing chamber 20 and the rear side is divided into the pressure increasing chamber 20. When the jaw 7 is opened as shown in FIG.
The front end face of the floating cam 10 is in contact with the rear end face of the floating cam 10. The fluid line 15 connected to the pressure fluid supply source opens in both the check valve 21 and the pressurizing chamber 19, and also the check valve
The pressure increasing chamber 20 and the storage groove 13 are communicated with each other through the fluid pipes 15b and 15c, and as shown in the drawing, the storage groove 13 is in the normal state.
The flow passage on the side is closed by a check valve 21, and the flow passage is always filled with oil.

The work 11 is supplied in the same manner as in the first embodiment,
When the draw screw 8 is pulled and the chucking operation is started, the pressure oil is supplied to the fluid pipe 15 at the same time, but since the oil is contained in the reservoir groove 13 side as described above,
The oil enters the pressurizing chamber 19 without opening the check valve 21, presses the floating piston 18, and pushes down the floating piston 18 as shown in FIG. 4, thereby strongly increasing the pressure of the oil in the reservoir groove 13. As a result, the gripping body 12 is elastically deformed, and the center pin 4 is clamped and held in the same manner as described above to perform the centering operation.

When the machining of the workpiece 11 is completed and the supply of the pressure oil to the pressurizing chamber 19 is stopped, the floating piston 18 slightly advances due to the pressure difference between the pressurizing chamber 19 and the pressure increasing chamber 20, and the floating piston 18 is closed by the advancing of the floating piston 18. The flow path on the side of the storage groove 13 that is formed has a negative pressure, but this negative pressure is corrected by opening the check valve 21 and sucking oil. The floating piston 18, which has advanced slightly as described above, has its rear end face pushed by the front end face of the floating cam 10 which eventually advances, and advances while sucking oil from the check valve 21 and returns to the state of FIG. According to this embodiment, since the pressure increasing mechanism 16 is built in the chuck body 2, the fluid pressure for the draw screw 8 can be increased to operate the gripping body 12, and the pressure fluid supply source can be used as the chuck. Can be shared with.

Finally, the embodiment shown in FIG. 5 will be described. In both of the above-mentioned two embodiments, the pressure fluid supply source is installed outside the chuck body 2, but this embodiment is a model in which an oil tank is built in and is as follows. In FIG. 5, reference numeral 22 denotes an oil tank, which is a piston 23 sealed in the oil tank 22 and urged by a spring 24 to constantly pressurize the oil in the oil tank 22 to a predetermined pressure. This is similar to the second embodiment.

Since the present embodiment is as described above, hydraulic pressure acts on the floating piston 18 even when the jaw 7 is open, as shown in FIG.
The pressure oil is prevented from flowing into the inside, and the pressure increasing operation is prevented from being performed except when desired. When the floating cam 10 retracts and starts gripping the workpiece 11, the floating piston 18 retracts while introducing pressure oil into the pressurizing chamber 20 accordingly, and the pressure boosting operation is performed as described above to center the gripping body 12. When the pin 4 is held under pinching pressure and the floating cam 10 moves forward, the floating piston 18 is pushed against this, and the pressure oil is forced back against the spring 24 while returning the pressure oil to the oil tank 22 to return to the old state. Restore. In this embodiment, since the oil tank as the pressure fluid supply source for operating the gripping body is built in the chuck body, the fluid conduit can be simplified.

As described in detail above, in the compensating chuck of the present application, the holder is attached to the shaft center of the chuck body, and the gripping body having the center hole in the fitting portion at the center of the holder has the shaft center. The gripping body is fitted and fixed so as to match the shaft center of the main body, and this gripping body is made of a material that is easily elastically deformed. Between them, a pressure-fluid storage groove having a closed chamber shape is formed, and the bottom of the storage groove is made thinner than the axial front and rear portions of the gripping body, and the center pin is axially moved into the center hole of this gripping body. A fluid pipe line that connects as much as possible and that connects the storage groove and the pressure fluid supply source is provided, and the thin portion elastically deforms and hugs the center pin outer periphery by the fluid pressure supplied to the storage groove. To hold the pressure Since it is configured to, the gap between the gripping body and the center pin can be absorbed regardless of the amount of play, and the axis of the chuck body and the center pin can be aligned with extremely good precision, and extremely high precision gripping can be achieved. The gripping accuracy can be maintained, and the desired accuracy can be maintained without deterioration with time. Further, even if the gap between the center pin and the gripping body is slightly large, the gripping body is elastically deformed and holds the clamping force, so that it is not necessary to machine the gripping body and the center pin with high precision as in the conventional case. There are advantages such as shortening the time. Further, in the present application, the fluid pressure is supplied to the storage groove of the gripping body to directly elastically deform the thin portion at the bottom of the storage groove, so that it is possible to reduce the force transmission loss with a simple configuration. .

[Brief description of drawings]

The drawings show the embodiment of the present application, and FIG.
FIG. 2 is a sectional view during operation, FIG. 3 is a sectional view during non-operation of another embodiment, FIG. 4 shows during operation of FIG. 3, and FIG. FIG. 6 is a cross-sectional view of the conventional device during operation. 1 ... Compensating chuck 2 ... Chuck body, 3 ... Holder 4 ... Center pin, 12 ... Gripping body 13 ... Reservoir groove, 16 ... Pressure boosting mechanism 18 ... Floating piston, 19 ... Pressure chamber 20 …… Increase chamber, 22 …… Oil tank 23 …… Piston, 24 …… Spring

Claims (1)

[Claims] 1. In a compensating chuck in which a center pin is axially movable on the axis of the chuck body and is biased forward, a holder is attached to the axis of the chuck body and the center of the holder is A gripping body with a central hole in the fitting part is fitted and fixed so that its axis coincides with the axis of the chuck body. This gripping body is made of a material that is easily elastically deformed, and its outer peripheral portion in the axial direction. In the fitting state with the holder, a surface is formed with a reservoir groove for the pressure fluid that becomes a closed chamber, and the bottom portion of the reservoir groove is thinner than the axial front and rear portion of the gripping body. And a fluid conduit connecting the center pin to the center hole of the gripper so as to be movable in the axial direction and connecting the reservoir groove and the pressure fluid supply source, and the fluid pressure supplied to the reservoir groove. Allows the thin portion to Compensating chuck, characterized by being configured to hold 挾圧 to embrace the center pin outer circumference and sex deformed.