JP2003251506A - Workpiece holding device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a workpiece holding device capable of detecting whether a workpiece is correctly clamped by a chuck member or not. <P>SOLUTION: This workpiece holding device 10 is provided with a chuck base member 13 and the chuck member 40 composed of a plurality of chuck claws 41. A chuck face 46 for grasping an outer peripheral face 1a of the workpiece 1 is formed on the chuck claw 41. A first air hole 50 is formed on the chuck face 46. A support metal member 60 is provided on an inner side of the chuck member 40. The support metal member 60 has a seating face 61 on which an end face 1b of the workpiece 1 is abutted. A second air hole 62 is formed on the seating face 61. An air supply source 25 is connected with the air holes 50, 62. Back pressure or differential pressure of air supplied by the air supply source 25 is detected by a pressure detector 30 to discriminate whether the workpiece 1 is in contact with the chuck face 46 and the seating face 61 correctly or not based on the detected pressure. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a work holding device capable of confirming that a work is held at a predetermined position when machining the work.

[0002]

2. Description of the Related Art FIG. 7 shows a hub carrier, which is a component of an automobile, as an example of a work 1 made of metal.
Track grooves 2 and 3 are formed on the inner peripheral surface of the work 1.
A plurality of balls roll on the track grooves 2 and 3, respectively. A hub (not shown) is rotatably supported via these balls.

Various types of machining, such as drilling, grinding and polishing of track grooves 2 and 3, are carried out at predetermined positions on the work 1 at a processing stage in a factory. Therefore, it is necessary to securely hold the work 1 at a predetermined position. For example, in a processing machine such as a lathe that performs processing while rotating a work, if the center of the processing machine and the center of the work are misaligned with each other, the processing accuracy becomes poor.

Conventionally, in order to detect whether or not the end surface of the workpiece is properly seated on the chuck-side seating surface, a small hole for ejecting air is formed in the seating surface to detect the back pressure of the air. Has proposed to determine whether the end surface of the work is in close contact with the seating surface.

[0005]

However, even if the end surface of the work and the seating surface are in close contact with each other in the processing machine, solid foreign matter such as cutting dust is caught between the chuck member and the outer peripheral surface of the work. If so, the center of the processing machine such as a lathe and the center of the work piece may be displaced from each other. If the work is rotated and machined in such a state that the center misalignment occurs, the machining accuracy becomes poor.

SUMMARY OF THE INVENTION Therefore, an object of the present invention is to provide a work holding device capable of holding a work at an accurate position with certainty.

[0007]

A work holding device of the present invention based on the first aspect is provided with a chuck base member and an inside or outside of the chuck base member, and grips an outer peripheral surface or an inner peripheral surface of a work. A chuck member that is movable in the radial direction of the work and has a first air hole formed in the chuck surface with which the outer peripheral surface or the inner peripheral surface contacts, and a chuck drive mechanism that drives the chuck member in the radial direction. A pad member provided on the chuck member, having a seating surface with which the end face in the axial direction of the workpiece comes into contact, and having a second air hole formed on the seating surface, and the first and second air holes. An air supply source for supplying air, a pressure detecting means for detecting a back pressure or a differential pressure of the air, and the work contacting the chuck surface and the seating surface based on the back pressure or the differential pressure. And a determination means for determining whether dolphin not.

When the outer peripheral surface or the inner peripheral surface of the work is clamped by the chuck member, the first air hole is covered by the outer peripheral surface or the inner peripheral surface of the work. Therefore, if the chuck member and the work are in close contact with each other, a predetermined back pressure or differential pressure is generated. If a foreign matter is caught between the chuck member and the work, air leaks from the first air hole, and the back pressure decreases. Or the differential pressure changes. When foreign matter is sandwiched between the seating surface of the pad member and the work, air leaks from the second air hole, and the back pressure decreases. Or the differential pressure changes.

In a preferred aspect of the present invention, the first and second air holes are formed at predetermined intervals at a plurality of circumferential positions of the chuck member.

According to a second aspect of the present invention, there is provided a work holding device according to the present invention, which has a seating surface on which a work abuts and which has air holes formed at a plurality of circumferential positions of the seating surface, and the above-mentioned backing member. A chuck member that is provided on the inner side of the chuck and is movable in the radial direction of the work to grab the inner peripheral surface of the work; a chuck drive mechanism that drives the chuck member in the radial direction; and an air that supplies air to the air hole. A supply source; a pressure detection unit that detects a back pressure or a differential pressure of the air; and a determination unit that determines whether or not the work is in contact with the seating surface based on the back pressure or the differential pressure. is doing.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION A first embodiment of the present invention will be described below with reference to FIGS. The work holding device 10 shown in FIG. 1 constitutes a chuck portion of a machine for machining such as a lathe. The work holding device 10 has a cylindrical rotating shaft 11 that is driven to rotate by a spindle rotating mechanism (not shown), a base plate 12 connected to the rotating shaft 11, and a cylindrical plate that is fixed to the base plate 12 and rotates integrally with the rotating shaft 11. The chuck base member 13 and the like are provided. A tapered guide surface 14 is formed on the inner peripheral side of the tip portion of the chuck base member 13.

An operating shaft 20 is inserted inside the rotary shaft 11. The operating shaft 20 can be relatively moved in the axial direction of the chuck base member 13 (direction shown by arrows A and B in FIG. 1) by an actuator (not shown). A locking portion 21 is formed near the tip of the operating shaft 20. Inside the operation shaft 20, a hole 22 for passing a coolant and an air supply hole 23 are formed along the axial direction of the operation shaft 20.

An air supply source 25, which is a compressed air supply source, is connected to the air supply hole 23 via an air supply path 24 such as an air pipe. The air supply path 24 or the air supply source 25 is provided with a pressure detector 30 as an example of pressure detection means for detecting a back pressure or a differential pressure of the supplied air.

The pressure detector 30 outputs an electric signal relating to pressure (back pressure or differential pressure) to a controller 31 having a calculation / control function using, for example, a microcomputer. The controller 31 functions as the determination means referred to in the present invention. The controller 31 is provided with the notification means 32.

A chuck member 40 is provided inside the chuck base member 13. As shown in FIG. 2, the chuck member 40 has a plurality of (for example, six) chuck claws 41 that are divided in the circumferential direction. These chuck claws 41
Are movable in the radial direction of the work 1 so that the outer peripheral surface 1a of the work 1 can be grasped.

A taper surface 42 that contacts the guide surface 14 is formed on the outer surface of each chuck claw 41. An arc-shaped contact member 45, a part of which is shown in FIG. 3, is attached to the inner surface of the tip of each chuck claw 41. On the inner peripheral surface of the contact member 45, a chuck surface 46 that contacts the outer peripheral surface 1 a of the work 1 is formed.

A first air hole 50 is formed in the chuck surface 46. The first air hole 50 is opened at a position facing the inner peripheral surface of the contact member 45, that is, the outer peripheral surface 1 a of the work 1. The first air holes 50 are formed at a plurality of positions in the circumferential direction of the chuck member 40.

The first air hole 50 has an air passage 51 formed in the contact member 45, an air passage 52 formed in the chuck base member 13, an air passage 53 formed in the base plate 12, and the like. , Communicates with the air supply hole 23.

The base 55 of the chuck member 40 is the operation shaft 20.
When the operating shaft 20 moves in the axial direction (directions indicated by arrows A and B) by engaging with the locking portion 21 of the chuck member 4,
0 also moves in the axial direction. When the chuck member 40 moves in the axial direction with respect to the chuck base member 13, the tapered surface 42 relatively moves in the axial direction with respect to the guide surface 14, whereby each chuck claw 41 moves in the radial direction of the work 1. To do. That is, the operation shaft 20, the guide surface 14, the taper surface 42, and the like constitute a chuck driving mechanism for driving the chuck member (collet chuck) 40 in the radial direction.

Inside of the chuck member 40, the pad member 6
0 is provided. As shown in FIG. 2, the pad member 6
Seating surfaces 61 having a flat shape are formed at a plurality of positions (for example, four positions) in the circumferential direction of 0. These seating surfaces 61
The end face 1b of the work 1 in the axial direction is in contact therewith.

As shown in FIG. 4, a second air hole 62 is formed in the seating surface 61. The second air holes 62 are formed at a plurality of positions in the circumferential direction of the pad member 60 according to the seating surface 61.

The second air hole 62 communicates with the air supply hole 23 through an air passage 63 formed in the backing member 60 and an air passage 64 formed in the chuck member 40. Therefore, compressed air can be supplied from the air supply source 25 to the first and second air holes 50 and 62.

A pressing member 70 is provided inside the pad member 60. The pressing member 70 is biased by a spring 71 in a direction in which the work 1 is pushed out from the contact metal member 60.

Controller 31 functioning as a judging means
Determines whether the work 1 is in proper contact with the chuck surface 46 and the seating surface 61 based on the back pressure or differential pressure of the air detected by the pressure detector 30.

For example, when the work 1 is in close contact with the chuck surface 46 and the seating surface 61, air is suppressed from coming out from the air holes 50 and 62, so that a predetermined level of back pressure or differential pressure is generated. However, if foreign matter such as chips is caught between the work 1 and the chuck surface 46 or between the work 1 and the seating surface 61, the work 1 and the chuck surface 4
6 or a seating surface 61 has a gap.

Therefore, the back pressure is lowered by the air leaking from the air holes 50 and 62. Or the differential pressure changes.
When the back pressure falls below a predetermined value or when the differential pressure changes, the controller 31 determines that the work 1 is poorly seated, and activates a warning light or a buzzer to notify the operator. I am trying to inform you of an abnormality.

Next, the operation of the work holding device 10 will be described. In FIG. 1, when the operating shaft 20 is driven in the direction of arrow A, the chuck member 40 also moves in the direction of arrow A, and the tapered surface 42 relatively moves in the axial direction with respect to the guide surface 14, whereby each chuck claw 41. Moves in the opening direction. In this state, the work 1 is fitted inside the chuck member 40, and the end surface 1b of the work 1 is brought into contact with the seating surface 61 of the pad member 60.

After that, when the operating shaft 20 is moved in the direction of arrow B, the tapered surface 42 of the chuck claw 41 moves relative to the guide surface 14 of the chuck base member 13 in the direction of arrow B, so that each chuck claw 41 moves. Move in the closing direction. Therefore, the chuck surface 46 causes the work 1
The outer peripheral surface 1a of the workpiece 1 is clamped, and the first air holes 50 are covered by the outer peripheral surface 1a of the work 1.

At this time, if foreign matter such as chips is caught between the outer peripheral surface 1a of the work 1 and the chuck surface 46, or between the end surface 1b of the work 1 and the seating surface 61, the work 1 and the chuck 1 are chucked. A gap is generated between the surface 46 or between the work 1 and the seating surface 61. Therefore, each air hole 5
Air leaks from at least one of 0 and 62, and the back pressure decreases. Or the differential pressure changes. When the back pressure falls below a predetermined value, or when the differential pressure changes, the controller 31 determines that the work 1 is poorly seated and informs the operator by operating the notifying means 32.

The work holding device 10 of the above embodiment
Is a structure for chucking the outer peripheral side of the work 1 (so-called outer diameter chuck), but the present invention is also applicable to a so-called inner diameter chuck for chucking the inner peripheral side of the work 1 in a work holding device for a lathe. it can.

5 and 6 show a work holding device 100 according to the second embodiment of the present invention. A work holding device 100 shown in FIG. 5 constitutes a chuck part of a machining center for performing machining such as drilling of the work 1, and includes a base 101 and a base plate 10 on the base 101.
2 and the chuck base member 103 fixed via the metal plate 2 and the metal plate member 104 fixed to the chuck base member 103.
And so on. A tapered guide surface 105 is formed on the outer peripheral portion of the chuck base member 103.

A piston 111 is housed in a cylinder chamber 110 formed inside the base body 101. Piston 1
11 is driven in the axial direction (direction shown by arrows C and D in FIG. 5) by hydraulic fluid pressurized by a hydraulic unit (not shown). An operation shaft 112 is connected to the piston 111. A taper member 113 is attached to the tip of the operation shaft 112.

An air supply hole 115 is formed in the base plate 102.
Are formed. An air supply source 25 is connected to the air supply hole 115 via an air supply path 24. The pressure detector 3 is provided in the air supply path 24 or the air supply source 25.
0 is provided, and the detected pressure signal is input to the controller 31.

A chuck member 120 is provided on the outer peripheral side of the tip of the chuck base member 103. The chuck member 120 is composed of a plurality of chuck claws 121 that are divided in the circumferential direction. These chuck claws 1
Reference numeral 21 is movable in the radial direction of the work 1 so that the inner peripheral surface 1c of the work 1 can be grasped.

On the inner peripheral side of each chuck claw 121, a tapered surface 125 contacting the guide surface 105 and the tapered member 11 are provided.
The taper surface 126 which contacts 3 is formed. On the outer peripheral side of the tip of each chuck claw 121, the inner peripheral surface 1c of the work 1
Is formed with a chuck surface 127.

When the piston 111 is moved in the axial direction (direction shown by arrows C and D in FIG. 5), the piston 111, the operating shaft 112, and the taper member 113 are integrally moved in the axial direction. Therefore, the guide surface 105 and the taper member 113
Thus, the chuck claw 121 is driven in the radial direction of the work 1. That is, the guide surface 105 and the taper member 11
3, the cylinder chamber 110, the piston 111, and the like constitute a chuck drive mechanism for driving the chuck member (collet chuck) 120 in the radial direction.

The pad member 104 has a seating surface 130 with which the axial end surface 1d of the workpiece 1 abuts. Air holes 131 are formed in the seating surface 130. As shown in FIG. 6, the air holes 131 are formed at a plurality of positions at predetermined intervals in the circumferential direction of the chuck member 120. These air holes 131 communicate with the air supply holes 115 via the air passages 132 (shown in FIG. 5). Therefore, compressed air can be supplied from the air supply source 25 to the air holes 131.

The controller 31 determines that the work 1 is poorly seated when the back pressure of air becomes equal to or less than a predetermined value or when the differential pressure changes, as in the case described in the first embodiment. However, the operator is informed of the poor seating by operating a warning light or a buzzer.

Next, the operation of the work holding device 100 will be described. In FIG. 5, the piston 11 is driven by the hydraulic pressure.
When 1 is driven in the direction of arrow C, the taper member 113 moves in the direction of arrow C, whereby the taper member 113 is displaced in the axial direction. Therefore, each chuck claw 121 moves in the closing direction. In this state, the work 1 is attached to the chuck member 1
The end surface 1d of the work 1 is brought into contact with the seating surface 130 of the contact metal member 104 while being fitted to the work piece 20.

After that, when the piston 111 is driven in the direction of arrow D, the taper member 113 is displaced in the direction approaching the guide surface 105, so that the taper surfaces 125 and 126 are pressed from the inside. Therefore, each chuck claw 121 moves in the expanding direction, whereby the inner peripheral surface 1c of the work 1 is fixed by the chuck surface 127.

At this time, the end surface 1d of the work 1 and the seating surface 1
If foreign matter such as cutting chips is sandwiched between the work piece 1 and the work piece 30, a gap is created between the work piece 1 and the seating surface 130, so that air leaks from the air hole 131 and the back pressure is reduced. Or the differential pressure changes. The controller 31 determines that the work 1 is poorly seated when the back pressure falls below a predetermined value or when the differential pressure changes, and notifies the operator by operating a warning light or a buzzer.

[0042]

According to the invention described in claim 1, in the state where the work is clamped at a predetermined position by the chuck member, not only can the quality of the seated state between the work and the seating surface be determined, but also the outer peripheral surface of the work can be determined. Alternatively, the contact state between the inner peripheral surface and the chuck member can be surely grasped. Therefore, it is possible to prevent the work from tilting and the centers of the work and the chuck member from deviating from each other, and it is possible to accurately perform machining or the like.

According to the invention described in claim 2, the first and second portions formed at a plurality of positions in the circumferential direction of the chuck member.
With the air holes of 1, the seated state between the work and the seating surface and the contact state between the work and the chuck member can be detected more accurately.

According to the third aspect of the present invention, it is possible to accurately determine the seating state of the work on the seating surface, so that it is possible to prevent the work from tilting or causing a defective clamp.

[Brief description of drawings]

FIG. 1 is a cross-sectional view taken along an axial direction of a work holding device according to a first embodiment of the present invention.

FIG. 2 is a front view of the work holding device shown in FIG.

FIG. 3 is a front view showing, in a partial cross section, a contact member of a chuck claw of the work holding device shown in FIG.

FIG. 4 is a cross-sectional view taken along the radial direction of the abutment member and the abutting member of the work holding device shown in FIG.

FIG. 5 is a cross-sectional view taken along the axial direction of the work holding device according to the second embodiment of the present invention.

6 is a plan view of the work holding device shown in FIG.

FIG. 7 is a sectional view showing an example of a work.

[Explanation of symbols]

1 ... work 10 ... Work holding device 13 ... Chuck base member 25 ... Air supply source 30 ... Pressure detector (pressure detecting means) 31 ... Controller (determination means) 40 ... Chuck member 41 ... Chuck claw 46 ... Chuck surface 50 ... First air hole 60 ... Patch member 61 ... Seating surface 62 ... Second air hole 100 ... Work holding device 103 ... Chuck base member 104 ... Patch member 120 ... Chuck member 121 ... Chuck claw 127 ... Chuck surface 130 ... Seating surface 131 ... Air hole

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kimura Toshikatsu             1-1-1 Ishibegaoka, Ishibe Town, Koga District, Shiga Prefecture             Within NSK Ltd. F term (reference) 3C029 EE04 EE06                 3C032 FF04 GG34

Claims (3)

[Claims] 1. A chuck base member, which is provided inside or outside the chuck base member, is movable in the radial direction of the work so as to grab the outer peripheral surface or the inner peripheral surface of the work, and the outer peripheral surface or the inner peripheral surface. A chuck member in which a first air hole is formed on a chuck surface that abuts, a chuck drive mechanism that drives the chuck member in the radial direction, and a seat provided on the chuck member and an end surface of the workpiece in the axial direction abuts. A metal member having a surface and having a second air hole formed on the seating surface, an air supply source for supplying air to the first and second air holes, and a back pressure or a differential pressure of the air. Pressure detecting means for detecting, and judging means for judging whether or not the workpiece is in contact with the chuck surface and the seating surface based on the back pressure or differential pressure. Work holding device. 2. The work holding device according to claim 1, wherein the first and second air holes are respectively formed at a plurality of circumferential positions of the chuck member. 3. A metal fitting member having a seating surface with which a workpiece abuts and having air holes formed at a plurality of circumferential positions of the seating surface, and an inner peripheral surface of the workpiece provided inside the metal fitting member. A chuck member that is movable in the radial direction of the workpiece to be grasped, a chuck drive mechanism that drives the chuck member in the radial direction, an air supply source that supplies air to the air holes, and a back pressure or differential pressure of the air. A work holding device, comprising: a pressure detecting unit that detects the pressure; and a determining unit that determines whether or not the work is in contact with the seating surface based on the back pressure or the differential pressure.