US-12623360-B2 - Grasping device

US12623360B2US 12623360 B2US12623360 B2US 12623360B2US-12623360-B2

Abstract

A grasping device of the embodiment includes claw holding parts, a cam, pins, a motor, and a rail holding part. The claw holding parts are supported by rails in a slidable manner. The cam includes grooves or curved holes having a spiral shape provided around the rotation center and a hole provided at the rotation center. The pins each have one end engaged with the claw holding parts side and the other end engaged with the grooves or the curved holes of the cam. The motor includes a shaft to be fixed to the hole of the cam. The rail holding part is configured to hold the rails and engage a positioning jig with an end portion of the shaft at the side fixed to the cam and including a hole part with an inner peripheral surface where the outer peripheral surface of the jig is contactable.

Inventors

Shotaro MIYAWAKI
Yukimasa FUNASUGI
Chizumi Moteki
Shinichi Narita

Assignees

MINEBEA MITSUMI INC.

Dates

Publication Date: 20260512
Application Date: 20201216
Priority Date: 20191217

Claims (2)

1 . A grasping device, comprising: claw holding parts supported by rails in a slidable manner; a cam including grooves or curved holes having a spiral shape provided around a rotation center of the cam and a hole provided at the rotation center of the cam; pins each having a first end engaged with a side of the claw holding parts and a second end engaged with the grooves or the curved holes of the cam; a motor including a shaft to be fixed to the hole of the cam; and a rail holding part configured to hold the rails and engage a positioning jig with an end portion of the shaft at a side fixed to the cam and including a hole part with an inner peripheral surface where an outer peripheral surface of the jig is contactable, wherein a protruding part configured to engage with a recess part of the jig is provided at a leading end of the shaft exposed from the hole of the cam.
2 . The grasping device according to claim 1 , wherein a fixing part configured to hold the motor is fixed with the rail holding part.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS This application is a national stage entry of International Application No. PCT/JP2020/046920 filed on Dec. 16, 2020, which claims the benefit of priority to Japanese Application No. JP2019-227665, filed Dec. 17, 2019, the entire disclosures of which are hereby incorporated herein by reference. TECHNICAL FIELD The present invention relates to a grasping device. BACKGROUND ART In the related art, automation of production lines has been promoted to reduce production costs and stabilize quality, and automation using robots has been introduced to many production lines because of the versatility. A grasping device for grasping workpieces, such as parts, in such robots includes a grasping part including a plurality of claw parts and a driving part for driving the plurality of claw parts (see, for example, PTL 1, etc.). A grasping device including a grasping part of a type with opposite two claw parts sliding to contact and separate from each other sometimes uses a cam provided with a groove or a curved hole having a spiral shape to slide the claw parts. With such a configuration, the rotation of the cam causes the pin engaged with the groove or the curved hole of the cam to move toward and away from the rotation axis, enabling the claw parts to slide. CITATION LIST Patent Literature JP 2016-144863A SUMMARY OF INVENTION Technical Problem In the above-described cam, however, the contact between the groove of the cam and the pin connected to the claw parts should be properly made, but it is difficult to perform accurate positioning during the assembling. When the positioning is not accurately performed, the efficiency of the slide movement may be decreased, or the cam may be worn. In view of the above, an object of the present invention is to provide a grasping device capable of performing proper contact between the groove of the cam and the pin through accurate positioning and preventing decrease in efficiency of the slide movement and wear of the cam. Solution to Problem To solve the above-described problems and achieve the object, a grasping device according to an aspect includes claw holding parts, a cam, pins, a motor, and a rail holding part. The claw holding parts are supported by rails in a slidable manner. The cam includes grooves or curved holes having a spiral shape provided around the rotation center and a hole provided at the rotation center. The pins each have one end engaged with the claw holding parts side and the other end engaged with the grooves or the curved holes of the cam. The motor includes a shaft to be fixed to the hole of the cam. The rail holding part configured to hold the rails and engage a positioning jig with an end portion of the shaft at the side fixed to the cam and including a hole part with an inner peripheral surface where the outer peripheral surface of the jig is contactable. The grasping device according to an aspect of the present invention can provide a grasping device capable of performing proper contact between the grooves of the cam and the pins through accurate positioning and preventing decrease in efficiency of the slide movement and wear of the cam. BRIEF DESCRIPTION OF DRAWINGS FIG. 1 is an explanatory diagram of a robot according to an embodiment. FIG. 2 is a front view illustrating a configuration of a grasping device according to the embodiment. FIG. 3 is a side view illustrating the configuration of the grasping device according to the embodiment. FIG. 4 is a perspective view illustrating a configuration of a fixing part according to the embodiment. FIG. 5 is a diagram (1) for describing a driving mechanism of the grasping device according to the embodiment. FIG. 6 is an exploded view of a main part of a grasping part. FIG. 7 is a diagram (2) for describing the driving mechanism of the grasping device according to the embodiment. FIG. 8 is a perspective view illustrating a configuration of a cam according to the embodiment. FIG. 9 is a flowchart illustrating a production step for the cam. FIG. 10 is a flowchart illustrating an assembling step for the grasping device. FIG. 11 is a perspective view illustrating a state in each assembling step for the grasping device. FIG. 12 is a longitudinal sectional view illustrating when the cam is fixed to a shaft of a motor of a driving part. FIG. 13 is a longitudinal sectional view illustrating when the grasping part is fixed to the driving part and the fixing part. FIG. 14 is a perspective view (1) of a rail holding part. FIG. 15 is a perspective view (2) of the rail holding part. DESCRIPTION OF EMBODIMENTS A grasping device according to the embodiment is described with reference to the accompanying drawings. Note that the present invention is not limited to the embodiment described above. Further, the dimensional relationships between elements, proportions of the elements, and the like in the drawings may differ from reality. Among the drawings, parts having mutually different dimen