JP2006007379A - Method and tool for holding work - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and a tool for holding a work capable of preventing the work from damaging the work at the time of mounting the work to the holding tool or transporting the work mounted to the holding tool, capable of restraining vibrations or deformation by three-point support with high rigidity at the time of machining or measuring, and having good repeatability of a position of the work in spite of attachment/detachment of the work. <P>SOLUTION: In the holding method for holding the work, the work is supported at three contact points on the periphery of the work while changing the rigidity of the three-point support. In the work holding tool for holding the work, the work is supported in point-contact at the three points in the periphery of the work while the support rigidity of the three-point support is changed. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a work holding method and a work holding jig used in an apparatus for processing and measuring a work.

  As a workpiece holding method used in a workpiece processing device, a measuring device, and other various measuring devices, a holding method as shown in FIG. 6 is conventionally used as disclosed in Patent Document 1. It has been. That is, the cylindrical holder 102 is internally processed with two inner diameters, and an inward flange 103 is formed. On the upper surface of the flange 103. As shown in FIG. 6, three support balls 104 are arranged at equal intervals (120 ° intervals) so that the workpiece 101 can be supported at three points. A positioning unit 105 is screwed to the upper surface of the holder 102. When the workpiece 101 is set in the holder 102, the screw 106 is loosened and the positioning unit 105 is moved outward in advance. The orientation of the workpiece 101 is always constant by the positioning unit 105. A three-point support structure is employed so that the workpiece 101 does not make a solid contact with the holder 102. Here, “per solid” means a holding state in which the work is supported by the holder in a ring shape from a macro viewpoint, but the work is supported by the holder at several points from a micro viewpoint. To do. In such a solid holding structure, even if the workpiece is set on the holder in the same manner every time, the support point is actually different every time. If the support point is different each time, naturally, the amount of deformation of the own weight at the support point is also different each time, resulting in a decrease in processing accuracy and measurement accuracy. Adopting three-point support ensures reproducibility of the amount of deformation of the workpiece due to solid contact.

  However, when the weight of the workpiece is large, the load is concentrated on the three points by adopting the three-point support structure, which greatly distorts the workpiece. As a means for coping with this problem, as disclosed in Patent Document 2, there is a method of mounting a load adjusting means for adjusting a pressing load to the three-point support portion of the work on the holder.

JP-A-11-58197 JP-A-6-94446

  However, the conventional example as described above has the following problems.

  1) Although the three-point support method is excellent as a work support method, the support rigidity is weaker than when the work is supported by a solid surface, and the work is deformed into an asymmetric so-called mussel shape by the work weight, and the work is A phenomenon of vibration at a low frequency occurs. Although it is possible to avoid mussel-shaped deformation by using the pressing load adjusting means disclosed in Japanese Patent Laid-Open No. 6-94446, it is the support rigidity of the three-point support that governs the frequency at which the workpiece vibrates. Thus, a vibration phenomenon at a low frequency occurs.

  2) When the hardness of the contact part of the three-point support is higher than that of the workpiece, the workpiece is clamped with an impact when the workpiece is mounted on the holding jig or when the workpiece is transferred to the holding jig. Since there is a fear, it is necessary to adopt a material whose hardness is lower than that of the work for the three-point support portion. However, a material with low hardness generally has low rigidity and further reduces the vibration frequency of the workpiece.

  3) Further, when the workpiece holding means is employed in the workpiece shape measuring device, especially when the workpiece is a lens, the shape measuring device is a three-dimensional coordinate measuring device or the like, and a probe having a sphere at the tip is used. The coordinates are measured by contacting the lens surface from one side of the lens. When a workpiece is held with a three-point support with low support rigidity, the contact portion of the three-point support is deformed by a minute fluctuation in the contact force of the probe, and the workpiece is displaced relative to the holding jig. There was a problem that the accuracy decreased.

  Therefore, the present invention has been made in view of the above-mentioned unsolved problems of the prior art, and is transported when a workpiece is mounted on a holding jig or with a workpiece mounted on the holding jig. A workpiece holding method that does not add wrinkles to the workpiece when performing machining, and can suppress vibrations and deformation with a highly rigid three-point support during machining and measurement. And it aims at providing a workpiece holding jig.

  In order to achieve the above object, the workpiece holding method of the present invention is a holding method for holding a workpiece, wherein the workpiece is supported in a point contact manner at three points in the peripheral portion of the workpiece, and the three-point support is supported. The rigidity is switched.

  In the workpiece holding method of the present invention, it is preferable that the workpiece is supported in a point contact manner by a sphere at three points in the peripheral portion of the workpiece.

  In the work holding method of the present invention, it is preferable to have a movable support mechanism different from the three-point support for switching the support rigidity.

  Furthermore, in the workpiece holding method of the present invention, it is preferable to switch the support state between when the workpiece is transported while being held and when the workpiece is operated.

  The workpiece holding jig according to the present invention is a workpiece holding jig for holding a workpiece, and supports the workpiece in a point contact manner at three points on the periphery of the workpiece, and switches the support rigidity of the three-point support. It is characterized by that.

  In the workpiece holding jig of the present invention, it is preferable that the workpiece is supported in a point contact manner by a sphere at three points in the peripheral portion of the workpiece.

  The workpiece holding jig of the present invention preferably has a movable support mechanism different from the three-point support for switching the support rigidity.

  In the work holding jig of the present invention, it is preferable to switch the support state between when the work is held and the work is held and when the work is performed on the work.

  Furthermore, in the work holding jig of the present invention, three work support mechanisms each having a ring-shaped holder for holding the work and provided with support balls for supporting the work are arranged at equal intervals on the holder. In addition to the three work support mechanisms, a movable support mechanism is arranged on the holder so that the support state can be switched.

  According to the work holding method and the work holding jig of the present invention, the work is supported by a support having low rigidity when the work is detached from the holding jig or when the work is mounted on the holding jig. This reduces the risk of catching workpieces and improves yield. Further, at the time of machining or measurement, it is possible to perform highly accurate machining or measurement with suppressed vibration and deformation by supporting the workpiece with a highly rigid three-point support. Furthermore, since the workpiece is supported at three points, the workpiece can be held with little positional error due to the attachment / detachment of the workpiece.

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

<Embodiment 1>
1A and 1B are schematic views of a workpiece holding jig according to Embodiment 1 of the present invention, in which FIG. 1A is a perspective view and FIG. 1B is a plan view. FIG. 2 shows the details of the movable support mechanism for the workpiece holding jig in Embodiment 1 of the present invention. FIG. 2 (a) is a sectional view of the movable support mechanism, and FIG. It is the figure seen from the A line.

  In FIG. 1, reference numeral 1 denotes a work holding jig for holding a work 2, which is installed in various devices such as a processing machine and a shape measuring device with the work 2 attached. The work holding jig 1 has a ring-shaped holder 3, and a movable support mechanism 4 (4 a to 4 c) that supports the work 2 is attached to the ring-shaped holder 3 with screws so as to be detachable from the holder. Handles 8 (8a, 8b) and pin holes 8 (8a, 8b) for positioning pins are provided. The handle 8 (8a, 8b) is used to lift the workpiece holding jig 1 when the workpiece holding jig 1 is installed or removed from various devices such as a processing machine or a shape measuring device. The pin holes 9 (9a, 9b) are provided corresponding to two positioning pins provided on the installation base of the work holding jig 1 of various apparatuses such as a processing machine and a shape measuring apparatus. This is for positioning the holding jig 1.

  The detail of the movable support mechanism 4 (4a-4c) is demonstrated using FIG.

  The movable support mechanisms 4 (4a to 4c) are provided at three positions on the ring-shaped holder 3 at equal intervals of 120 degrees. The movable support mechanism 4 (4a to 4c) includes a protrusion 3a slightly protruding inward from the inner surface of the holder 3, and a support ball 7 (7a to 7c) attached to the upper surface of the protrusion 3a by bonding. The support member 6 (6a to 6c) is connected to the driving means 5 (5a to 5c). The support balls 7 (7a to 7c) are provided at three equal intervals at an interval of 120 degrees on the ring-shaped holder 3, and the support members 6 (6a to 6c) are also formed on the ring-shaped holder 3. The support balls 7 (7a to 7c) and the support members 6 (6a to 6c) need to be arranged so that their positions are shifted (see FIG. 1 (b)). However, the amount of deviation may be any value.

  The driving means 5 (5a to 5c) and the support member 6 (6a to 6c) include a shaft 10 that transmits the driving force generated by the driving means 5 (5a to 5c) to the support member 6 (6a to 6c), and the support member 6 It is connected via the member 14 for adhering and fixing (6a-6c). The driving means 5 (5a to 5c) are attached to the upper surface of the ring-shaped holder 3 at three positions at equal intervals of 120 degrees. The driving means 5 (5a to 5c) may be any driving means, but in the present embodiment, it will be described as using an air cylinder.

  The holder 3 is provided with a shaft hole 12 for passing the shaft 10 and a notch 11 at three places where the driving means 5 (5a to 5c) are attached. A member 14 is installed in the notch 11, and the support member 6 (6 a to 6 c) is bonded to the member 14. The member 14 and the drive means 5 (5a-5c) are connected by the shaft 10. The support members 6 (6a to 6c) connected by the shaft 10 are movable in the vertical direction by driving the driving means 5 (5a to 5c). A bush 13 is preferably provided between the shaft hole 12 and the shaft 10 in order to reduce backlash to improve straightness and reduce wear due to contact. Further, as shown in FIG. 3, the shaft 10 and the bush 13 are preferably provided with a flat portion 15 for preventing rotation. Since the shaft 10 is restrained from rotating about the axial center by the anti-rotation flat portion 15, the support member 6 (6 a to 6 c) can move only in the vertical direction.

  In FIG. 2B, the height of the support member 6 (6a to 6c) moved in the vertical direction by the driving means 5 (5a to 5c) is the height dimension (1) at the time of ascent, and the support member 6 (6a It is necessary to make it larger than the height dimension (2) of the support balls 7 (7a to 7c) so that the workpiece 2 can be supported only by the three points ˜6c). Further, the height dimension (3) when lowered is the height of the support ball 7 (7a to 7c) so that the workpiece 2 can be supported by only three points of the support ball 7 (7a to 7c). It is necessary to make it smaller than the dimension (2).

  Further, it is preferable to use a hard material equivalent to or higher than the workpiece 2 for the support balls 7 (7a to 7c) for supporting the workpiece 2 during processing or shape measurement. If a material softer than the workpiece 2 is used for the support sphere 7 (7a to 7c), the contact rigidity between the support sphere 7 (7a to 7c) and the workpiece 2 is lowered, and the displacement of the workpiece 2 during processing or measurement is reduced. It must be avoided because it may fluctuate statically or generate low-frequency vibrations, causing deterioration in processing and measurement accuracy.

  Conversely, when the workpiece 2 is attached to or detached from the workpiece holding jig 1 or when the workpiece 2 is transported with the workpiece 2 mounted on the workpiece holding jig 1, the workpiece 2 is attached to the support member 6 (6 a to 6 c) that supports the workpiece 2. It is preferable to use a softer material or a configuration in which the support rigidity is low. If a material harder than the work 2 is used or a structure having a high support rigidity is used, there is a large risk of wrinkling the work 2 at the contact portion between the support member 6 (6a to 6c) and the work 2. Therefore, it must be avoided.

  Next, a method for using the workpiece holding jig 1 will be described.

  When placing the workpiece 2 on the workpiece holding jig 1, the driving means 5 (5a to 5c) is driven to raise the support member 6 (6a to 6c). Then, after adjusting the posture of the workpiece 2 so as to be placed on the workpiece holding jig 1, the workpiece 2 is carefully inserted into the workpiece holding jig 1, and the workpiece 2 is placed on the support members 6 (6a to 6c). Be supported. In this state, the workpiece holding jig 1 and the workpiece 2 are transported and installed to various devices such as a processing device and a measuring device. When installing, the alignment pin hole 9 (9a, 9b) provided in the workpiece holding jig 1 is aligned with the alignment pin on the apparatus side. When the workpiece holding jig 1 and the workpiece 2 are installed on the apparatus, the driving means 5 (5a to 5c) is driven to lower the support member 6 (6a to 6c), and the workpiece 2 is supported by the support ball 7. It is made to be supported by three points (7a-7c). At this time, it is necessary to make the descending speeds of the three support members 6 (6a to 6c) coincide with each other by adjusting the driving means 5 (5a to 5c) so that the posture of the workpiece 2 does not change.

  Further, the lowering speed needs to be adjusted in advance so as not to cause wrinkles when the work 2 comes into contact with the support balls 7 (7a to 7c). Processing and measurement are performed in a state where the workpiece 2 is supported by three points of the support balls 7 (7a to 7c). When the processing and measurement are completed, the driving means 5 (5a to 5c) is driven to raise the support member 6 (6a to 6c) and support the workpiece 2 with the support member 6 (6a to 6c). Also at this time, it is necessary to make the ascending speeds of the three support members 6 (6a to 6c) coincide with each other by adjusting the driving means 5 (5a to 5c) so that the posture of the workpiece 2 does not fluctuate. Then, the workpiece holding jig 1 and the workpiece 2 are taken out from various devices such as a processing device and a measuring device in a state where the workpiece 2 is supported by the support member 6 (6a to 6c), and conveyed to a predetermined position.

  By implementing the method of using the workpiece holding jig 1 as described above, the workpiece 2 is removed when the workpiece 2 is attached to or detached from the workpiece holding jig 1 or when the workpiece 2 is transported with the workpiece 2 mounted thereon. Therefore, the yield can be improved, and highly accurate machining and measurement can be performed while suppressing vibration, displacement and deformation of the workpiece 2 during machining and measurement.

<Embodiment 2>
Next, a second embodiment of the present invention will be described.

  4A and 4B are schematic views of a workpiece holding jig according to Embodiment 2 of the present invention, where FIG. 4A is a perspective view and FIG. 4B is a plan view. FIG. 5 shows the details of the movable support mechanism of the workpiece holding jig in Embodiment 2 of the present invention. FIG. 5 (a) is a sectional view of the movable support mechanism and the movable support mechanism is raised. (B) is a figure of the state which the movable support mechanism lowered. In addition, in the member of this Embodiment, the same code | symbol is attached | subjected to the same member as previous Embodiment 1, and detailed description is abbreviate | omitted.

  The details of the movable support mechanism 4 (4a to 4c) will be described with reference to FIG.

  The movable support mechanisms 4 (4a to 4c) are provided at three positions on the ring-shaped holder 3 at equal intervals of 120 degrees. The movable support mechanism 4 (4a to 4c) includes a driving means 5 (5a to 5c) attached to the upper surface of the ring-shaped holder 3 at three positions at regular intervals of 120 degrees, and a support member 6 (6a to 6c). ) Are bonded and held above and below the member 14, and the upper guide 16 and the lower guide 17 for guiding the operation of the support member 6 and the member 14 in the vertical direction, the stopper 18 for abutting the member 14, A spring 19 for pushing up the member 14 is provided. In addition, although this drive means 5 (5a-5c) may use what kind of drive means, in this Embodiment, it demonstrates as what uses an air cylinder.

  The ring-shaped holder 3 is provided with a shaft hole 12 and a notch 11 through which the shaft 10, the upper guide 16, and the lower guide 17 are passed at three places where the driving means 5 (5 a to 5 c) are attached. Between the shaft hole 12 and the shaft 10, the upper guide 16, and the lower guide 17, the backlash of the shaft 10, the upper guide 16, and the lower guide 17 is reduced to improve straightness, and wear due to contact is reduced. Therefore, it is preferable to provide the bush 13. Further, as shown in FIG. 3, it is preferable that the shaft 10, the upper guide 16, the lower guide 17 and the bush 13 are provided with a rotation-preventing flat portion 15. Since the shaft 10, the upper guide 16, and the lower guide 17 are restrained from rotating about the axial center by the anti-rotation flat portion 15, the support member 6 (6 a to 6 c) can move only in the vertical direction.

  It is preferable to use a hard material equivalent to or higher than the workpiece 2 for the support member 6 (6a to 6c) that supports the workpiece 2 during processing or shape measurement. If a material softer than the workpiece 2 is used for the support member 6 (6a to 6c), the contact rigidity between the support member 6 (6a to 6c) and the workpiece 2 is reduced, and the displacement of the workpiece 2 during processing or measurement is reduced. It must be avoided because it may fluctuate statically or generate low-frequency vibrations, causing deterioration in processing and measurement accuracy.

  Further, as shown in FIG. 5A, the spring 19 drives the driving means 5 (5a to 5c) while the work 2 is placed on and supported by the support member 6 (6a to 6c). When the shaft 10 is raised, the spring stiffness is not selected appropriately so that the clearance 20 between the shaft 10 and the upper guide 16 and the clearance 21 between the member 14 and the stopper 18 are ensured. Don't be. Moreover, the spring stiffness of the spring 19 is such that the workpiece 2 is attached to the workpiece holding jig 1 when the workpiece 2 is attached to or detached from the workpiece holding jig 1 at the contact portion between the workpiece 2 and the support member 6 (6a to 6c). In order to prevent the work 2 from being wrinkled when transported in a state where it is transported, it must have a reasonably low rigidity.

  Next, a method for using the workpiece holding jig 1 will be described.

  When the workpiece 2 is placed on the workpiece holding jig 1, the driving means 5 (5a to 5c) is driven to raise the shaft 10, and the support member 6 (6a to 6c) and the member 14 are pushed up by the spring 19 to support the member. 6 (6a-6c) is in a state where the support rigidity is lowered. Then, after adjusting the posture of the workpiece 2 so as to be placed on the workpiece holding jig 1, the workpiece 2 is carefully inserted into the workpiece holding jig 1, and the supporting member 6 (6a to 6a in a state where the supporting rigidity is low). The workpiece 2 is supported by 6c). In this state, the workpiece holding jig 1 and the workpiece 2 are transported and installed to various devices such as a processing device and a measuring device. When installing, the alignment pin hole 9 (9a, 9b) provided in the workpiece holding jig 1 is aligned with the alignment pin on the apparatus side. When the workpiece holding jig 1 and the workpiece 2 are installed on the apparatus, the driving means 5 (5a to 5c) is driven, the upper guide 16 is pushed by the shaft 10, and the member 14 is abutted against the stopper 18. The support rigidity of the support member 6 (6a to 6c) that supports the workpiece 2 is increased. At this time, it is necessary to make the descending speeds of the three support members 6 (6a to 6c) coincide with each other by adjusting the driving means 5 (5a to 5c) so that the posture of the workpiece 2 does not change.

  Processing and measurement are performed in a state where the workpiece 2 is supported by the support member 6 (6a to 6c) having a high support rigidity. When the processing and measurement are completed, the driving means 5 (5a to 5c) is driven to raise the shaft 10, and the support member 6 (6a to 6c) and the member 14 are pushed up by the spring 19 to support the support member 6 (6a The workpiece 2 is supported in a state where the support rigidity of .about.6c) is lowered. Also at this time, it is necessary to make the ascending speeds of the three support members 6 (6a to 6c) coincide with each other by adjusting the driving means 5 (5a to 5c) so that the posture of the workpiece 2 does not fluctuate. Then, the workpiece holding jig 1 and the workpiece 2 are taken out from various devices such as a processing device and a measuring device in a state where the workpiece 2 is supported by the supporting member 6 (6a to 6c) in a state where the supporting rigidity is low, and are moved to a predetermined position. Transport.

  By implementing the method of using the workpiece holding jig 1 as described above, the workpiece 2 is removed when the workpiece 2 is attached to or detached from the workpiece holding jig 1 or when the workpiece 2 is transferred to the workpiece holding jig 1. Therefore, the yield can be improved, and highly accurate machining and measurement can be performed while suppressing vibration, displacement and deformation of the workpiece 2 during machining and measurement.

It is the schematic of the workpiece holding jig in Embodiment 1 of this invention, (a) is a perspective view, (b) is a top view. The details of the movable support mechanism of the workpiece holding jig in Embodiment 1 of the present invention are shown, wherein (a) is a cross-sectional view of the movable support mechanism, and (b) is viewed from line AA in (a). It is a figure. It is sectional drawing along the BB line of Fig.2 (a), and sectional drawing along the BB line of Fig.5 (a). It is the schematic of the workpiece holding jig in Embodiment 2 of this invention, (a) is a perspective view, (b) is a top view. The detail of the movable support mechanism of the workpiece holding jig in Embodiment 2 of this invention is shown, (a) is a figure of the state which the movable support mechanism raised, (b) is the movable support mechanism lowered. It is a figure of a state. It is the schematic explaining the conventional workpiece holding method, (a) is a top view, (b) is sectional drawing along the AA in (a).

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Work holding jig 2 Work 3 Holder 3a Protruding part 5 (5a-5c) Drive means 6 (6a-6c) Support member 7 (7a-7c) Support ball 8 (8a, 8c) Handle 9 (9a, 9c) Pin Hole 10 Shaft 11 Notch 12 Shaft hole 13 Bush 14 Member 15 Anti-rotation plane 16 Upper guide 17 Lower guide 18 Stopper 19 Spring 20 Gap 21 Gap 101 Work 102 Holder 103 Flange 104 Support ball 105 Positioning unit 106 Screw

Claims (9)

  A holding method for holding a workpiece, characterized in that the workpiece is supported in a point contact manner at three points in a peripheral portion of the workpiece, and the support rigidity of the three-point support is switched.   The work holding method according to claim 1, wherein the work is supported in a point-contact manner by a sphere at three points in a peripheral portion of the work.   The work holding method according to claim 1, further comprising a movable support mechanism different from the three-point support for switching the support rigidity.   2. The work holding method according to claim 1, wherein the support rigidity is switched between when the work is transported while being held and when the work is performed on the work.   A workpiece holding jig for holding a workpiece, wherein the workpiece is supported in a point contact manner at three points around the workpiece, and the support rigidity of the three-point support is switched.   6. The workpiece holding jig according to claim 5, wherein the workpiece is supported in a point contact manner by a sphere at three points in a peripheral portion of the workpiece.   6. The work holding jig according to claim 5, further comprising a movable support mechanism different from the three-point support for switching the support rigidity.   6. The work holding jig according to claim 5, wherein the support state is switched between when the work is transported while being held and when the work is performed on the work.   Three work support mechanisms each having a ring-shaped holder for holding a work and provided with support balls for supporting the work are arranged at equal intervals on the holder, and movable separately from the three work support mechanisms. A work holding jig characterized in that a supporting mechanism is arranged on the holder so that the support state can be switched.

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