Work transfer apparatus

Abstract

To provide a workpiece conveying device capable of suppressing cost low with a simple structure.SOLUTION: The workpiece transfer device 101 includes the mount 10, the main body portion 20 having the movable base 28 movable in the lateral directions X and Y of the mount 10 and movable up and down in the vertical direction Z of the mount 10, the workpiece gripping mechanism portion 30 capable of gripping the 1a portion of the outer peripheral surface of the workpiece 1 from the outside in the radial direction D in a state where the workpiece 1 is placed such that the workpiece center axis L extends along the vertical direction Z, and the suspension chain 40 for suspending the workpiece gripping mechanism portion 30 from the movable base 28 of the main body portion 20 so as to be swingable in the lateral plane. The suspending chain 40 allows the holding 1a axial line M to move so as to overlap with the work center axial line L in a horizontal plane by following positional dislocation of the holding center axial line M in the horizontal directions X and Y to the work center axial line L when the work holding mechanism part 30 holds the outer peripheral surface center part.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a workpiece transport device. [Background technology]

[0002] Patent Document 1 below discloses a vehicle tire transport device as an example of this type of work transport device. This transport device is equipped with a conveyor system and a work gripping mechanism for transporting vehicle tires, which are the workpieces. The conveyor system has a conveyor that supports the tires so that they can move in a predetermined horizontal direction. The work gripping mechanism has first and second gripping units for clamping and gripping two tires placed on the conveyor from both sides in the horizontal direction.

[0003] The workpiece gripping mechanism operates by placing the second gripping unit between two tires and pressing the first gripping unit against each tire from the side opposite the second gripping unit. At this time, each tire is pressed toward the second gripping unit by the load from the first gripping unit and moves horizontally on the conveyor. In this way, this conveying device uses the horizontal movement of each tire to eliminate horizontal misalignment of the workpiece gripping mechanism with respect to that tire. Then, each tire is finally clamped and gripped by the first gripping unit and the second gripping unit from both sides in the horizontal direction with the horizontal misalignment eliminated. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 6-170658 Summary of the Invention [Problem to be solved by the invention]

[0005] The above-described conveying device is configured to move a tire horizontally before gripping it, and therefore requires a conveyor system to allow the tire to move. This conveying device has the disadvantage of being structurally complex due to the conveyor system. Therefore, it is conceivable to use high-precision equipment such as position sensors and measurement and correction devices (e.g., vision systems) to prevent horizontal misalignment of the workpiece gripping mechanism relative to the tire. However, using high-precision equipment can complicate the structure and increase the device and running costs. Therefore, in designing this type of workpiece conveying device for transporting workpieces with circular outer peripheries, such as tires, a technology is needed that can prevent the structure from becoming too complex and suppress cost increases.

[0006] The present invention has been made in view of the above-mentioned problems, and aims to provide a workpiece transport device that has a simple structure and can keep costs low. [Means for solving the problem]

[0007] One aspect of the present invention is A workpiece conveying device that conveys a workpiece having a circular outer circumferential surface, A stand and a main body portion having a movable base that is movable in the horizontal direction of the pedestal and that is movable up and down in the vertical direction of the pedestal; a workpiece gripping mechanism capable of gripping the outer peripheral surface of the workpiece from the outside in the radial direction in a state in which the workpiece is placed so that the workpiece central axis is aligned in the vertical direction; a hanging member that hangs the workpiece gripping mechanism from the movable base of the main body so that the workpiece gripping mechanism can swing freely within a horizontal plane; Equipped with the hanging member allows the gripping central axis to move in a horizontal plane so as to overlap with the workpiece central axis, following the horizontal positional deviation of the gripping central axis with respect to the workpiece central axis when the workpiece gripping mechanism grips the outer peripheral surface of the workpiece. Work transport device, is located. [Effects of the Invention]

[0008] In the workpiece transport device of the above aspect, the workpiece gripping mechanism, which can grip the outer peripheral surface of the workpiece from the radially outer side, is suspended from the movable base of the main body by a suspension member so as to be swingable within a horizontal plane. The suspension member allows the gripping central axis of the workpiece gripping mechanism to move within the horizontal plane so as to overlap with the workpiece central axis when the workpiece gripping mechanism grips the outer peripheral surface of the workpiece. Therefore, if the gripping central axis is horizontally misaligned with the workpiece central axis, the workpiece gripping mechanism suspended from the suspension member moves within the horizontal plane to correct this misalignment.

[0009] According to the above configuration, horizontal positional deviation of the workpiece gripping mechanism relative to the workpiece can be eliminated by utilizing a simple suspension structure with a suspension member, without using high-precision devices such as position sensors and measurement correction devices. Furthermore, by using a suspension member instead of a position sensor and measurement correction devices, the number of parts used can be reduced, thereby making it possible to reduce both initial costs and running costs.

[0010] As described above, according to the above-described aspect, it is possible to provide a workpiece transport device that has a simple structure and can keep costs low. [Brief explanation of the drawings]

[0011] [Figure 1] FIG. 1 is a perspective view of a workpiece transport device according to a first embodiment. [Figure 2] FIG. 2 is an enlarged perspective view of the workpiece gripping mechanism and its surroundings in FIG. 1. [Figure 3] FIG. 3 is a plan view of the workpiece gripping mechanism in FIG. 2 as viewed from above. [Figure 4] FIG. 2 is a side view of the workpiece gripping mechanism in FIG. 1 . [Figure 5] FIG. 2 is a block diagram of a control system for the workpiece conveyance device of the first embodiment. [Figure 6] FIG. 3 is a flowchart showing the operation of transporting a workpiece by the workpiece transport device of the first embodiment. [Figure 7] FIG. 7 is a side view of the workpiece gripping mechanism after the first step in FIG. 6 is performed. [Figure 8] FIG. 8 is a plan view of the workpiece gripping mechanism shown in FIG. 7, seen from above. [Figure 9] FIG. 7 is a side view of the workpiece gripping mechanism after the second step in FIG. 6 is performed. [Figure 10] FIG. 7 is a side view of the workpiece gripping mechanism after the third step in FIG. 6 is performed. [Figure 11] 7 is a plan view of the workpiece gripping mechanism seen from above in the first stage of the gripping operation in the third step of FIG. 6; [Figure 12] 7 is a plan view of the workpiece gripping mechanism seen from above in the second stage of the gripping operation in the third step of FIG. 6; FIG. [Figure 13] 7 is a plan view of the workpiece gripping mechanism in the third stage of the gripping operation in the third step of FIG. 6, as viewed from above. [Figure 14] FIG. 7 is a side view of the workpiece gripping mechanism after the fourth step in FIG. 6 is performed. [Figure 15] 10 is a plan view corresponding to FIG. 3 of a workpiece gripping mechanism of a workpiece transfer device according to a second embodiment. [Figure 16] 10 is a plan view corresponding to FIG. 3 of a workpiece gripping mechanism of a workpiece transfer device according to a third embodiment. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0012] Preferred embodiments of the above aspects are described below.

[0013] In the work transport device of the above-mentioned aspect, it is preferable that the work gripping mechanism unit comprises a guide frame attached to the lower end of the hanging member, a plurality of slide arms guided in the radial direction by the guide frame between the non-gripping position and the gripping position, and a gripping unit provided on each of the plurality of slide arms so as to slide between the non-gripping position and the gripping position in accordance with the radial movement.

[0014] According to this workpiece transport device, the workpiece gripping mechanism is configured by a guide frame, a plurality of slide arms, and a plurality of gripping portions, thereby simplifying the structure of the workpiece gripping mechanism.

[0015] In the workpiece transport device of the above aspect, it is preferable that the gripping portion has a first gripping member and a second gripping member arranged side by side in a horizontal plane so as to be able to contact the outer peripheral surface of the workpiece, the second gripping member is attached to the slide arm via an elastic member so as to be able to be elastically displaced, and is configured to contact the outer peripheral surface of the workpiece in preference to the first gripping member when the gripping portion slides from the non-gripping position to the gripping position, and the second gripping member is configured to move along the outer peripheral surface of the workpiece in response to a reaction force received from the workpiece when the gripping central axis is misaligned with the workpiece central axis, until the gripping central axis overlaps the workpiece central axis, and to be elastically displaced until both the first gripping member and the second gripping member are in contact with the outer peripheral surface of the workpiece.

[0016] According to this workpiece transport device, when the gripping unit slides from the non-gripping position to the gripping position, the second gripping member, which is elastically attached to the slide arm via an elastic member, contacts the outer circumferential surface of the workpiece before the first gripping member. If the gripping central axis is misaligned with the workpiece central axis, the second gripping member moves along the outer circumferential surface of the workpiece in response to the reaction force received from the workpiece, causing the gripping central axis to overlap with the workpiece central axis. In this way, the second gripping member can be used to absorb misalignment of the gripping central axis relative to the workpiece central axis in the horizontal plane. The second gripping member then elastically displaces until both the first and second gripping members contact the outer circumferential surface of the workpiece, allowing both the first and second gripping members to grip the outer circumferential surface of the workpiece.

[0017] In the workpiece transport device of the above aspect, the second gripping member is preferably a gripping roller that is rotatable around a rotation axis that extends along the up-down direction.

[0018] According to this workpiece transport device, by employing a rotary gripping roller as the second gripping member, the gripping roller rotates around the rotation axis in response to the reaction force received from the workpiece when it comes into contact with the outer circumferential surface of the workpiece, thereby moving smoothly along the outer circumferential surface of the workpiece. Therefore, the gripping roller can achieve the function required of the second gripping member.

[0019] In the workpiece transport device of the above aspect, the gripping portion of the workpiece gripping mechanism is preferably configured so that the second gripping members are arranged side by side on both sides of the first gripping member.

[0020] According to this workpiece transport device, by increasing the number of second gripping members by arranging two second gripping members side by side on both sides of the first gripping member, it is possible to improve the effect of absorbing positional deviation in the horizontal plane of the gripping central axis relative to the workpiece central axis. Also, by gripping the outer peripheral surface of the workpiece with one first gripping member and two second gripping members on either side of it, it is possible to improve gripping stability.

[0021] Hereinafter, specific embodiments of the workpiece transport device of the above aspect will be described with reference to the drawings.

[0022] In this specification and drawings, unless otherwise specified, mutually orthogonal horizontal directions are indicated by arrows X and Y, and the vertical direction is indicated by arrow Z.

[0023] (Embodiment 1) The workpiece transport device 101 of the first embodiment shown in FIG. 1 is a device that transports a workpiece 1 having a circular outer peripheral surface 1a. In this embodiment, the workpiece 1 is a rubber tire used for vehicle wheels. When the workpieces 1 are stored in a stacked state, such as lying on their sides (also referred to as horizontal stacking, tiered stacking, or flat stacking), the workpieces 1 are arranged so that the workpiece central axis L is aligned in the vertical direction Z. The workpiece transport device 101 can be suitably used to transport the workpieces 1 arranged in this manner.

[0024] The workpiece transport device 101 includes a base 10, a main body 20, a workpiece gripping mechanism 30, a hanging chain 40, and a control panel 50. The control panel 50 is used to control the base 10, the main body 20, and the workpiece gripping mechanism 30.

[0025] 1. Structure of the stand 10 1, the mount 10 is a frame for supporting the main body 20. The mount 10 of this embodiment has six support members 11 extending parallel to each other in the vertical direction Z, two beam members 12 extending parallel to each other in the horizontal direction Y, two sliders 13, and two guide rails 15 extending parallel to each other in the horizontal direction X.

[0026] The beam member 12 is provided to connect three support members 11 arranged at intervals in the horizontal direction Y. The slider 13 is attached to the beam member 12 so as to be able to move in the horizontal direction Y. Although not shown in detail, the slider 13 is equipped with an electric travel motor 14. The slider 13 is driven by the travel motor 14 and is able to move on the beam member 12 in the horizontal direction Y. The two guide rails 15 are used to guide the main body 20 in the horizontal direction X and are bridged between the two sliders 13.

[0027] The mount 10 may be any mount capable of supporting at least the main body 20, and the number and shape of its components are not limited to those shown in FIG.

[0028] 2. Structure of the main body 20 As shown in Fig. 1, the main body 20 has an electric travel motor 21, a main body frame 22, a plurality of wheels 23, a gear mechanism 24, a rotating shaft 25, an electric lifting motor 26, two lifting chains 27, and a movable base 28. The plurality of wheels 23 support the main body frame 22 so that it can travel along the guide rails 15. The main body 20 is capable of traveling in the horizontal direction X on the guide rails 15 using the travel motor 21 as a driving source. The gear mechanism 24 is attached to the main body frame 22. This gear mechanism 24 converts the driving force of the lifting motor 26 into rotational motion of the rotating shaft 25.

[0029] As shown in FIG. 2, the movable base 28 is suspended by two lifting chains 27. To ensure stable suspension of the movable base 28, it is preferable that the number of lifting chains 27 is two or more. In this embodiment, a roller chain with a known structure is used as the lifting chain 27. A roller chain has excellent guiding properties for the movable base 28 in the vertical direction Z, and also has the advantage of being able to suppress swinging of the movable base 28 within a horizontal plane.

[0030] Sprockets (meshing portions) 25a with which the lifting chains 27 mesh are provided at both axial ends of the rotation shaft 25. Each lifting chain 27 is driven by a lifting motor 26, allowing it to be pulled up and pulled down. A movable base 28 is connected to the lower ends of the two lifting chains 27 and suspended. The movable base 28 rises as the lifting chains 27 are pulled up, and falls as the lifting chains 27 are pulled down. The movable base 28 is also configured to move integrally with the main frame 22. That is, it moves in the horizontal direction X as the main frame 22 travels in the horizontal direction X, and moves in the horizontal direction Y as the main frame 22 travels in the horizontal direction Y. Therefore, the movable base 28 is movable in the horizontal directions X and Y of the gantry 10, and is also movable up and down in the vertical direction Z of the gantry 10.

[0031] 3. Structure of the workpiece gripping mechanism 30 2, the workpiece gripping mechanism 30 is suspended by a hanging chain 40 from a movable base 28 which is suspended by a lifting chain 27. Therefore, the workpiece gripping mechanism 30 is configured to be suspended sequentially from the main body 20 via a two-stage suspension structure (the first-stage lifting chain 27 and the second-stage hanging chain 40).

[0032] The workpiece gripping mechanism 30 is configured to be able to grip the outer peripheral surface 1a of the workpiece 1 from the outside in the radial direction D when the workpiece 1 is placed so that the workpiece central axis L is aligned in the vertical direction Z. To achieve this configuration, the workpiece gripping mechanism 30 includes a guide frame 31, two slide arms 32, a gripping cylinder 33, and two grippers 34.

[0033] The guide frame 31 is attached to the lower end 41 of each of the four hanging chains 40. The two slide arms 32 are guided by the guide frame 31 in synchronization with each other in the radial direction D (see FIG. 1) between a first position P1 and a second position P2 (described later).

[0034] The gripping cylinder 33 has a cylinder rod 33a connected to the two slide arms 32 (however, the connection structure with the two slide arms 32 is not shown). The cylinder rod 33a is configured to move back and forth using a driving force such as fluid pressure or an actuator. In this embodiment, the two slide arms 32 are guided in the horizontal direction X in conjunction with the forward and backward movement of the cylinder rod 33a.

[0035] The gripping portions 34 are provided on each of the two slide arms 32 so as to slide between a non-gripping position Q1 and a gripping position Q2 (described later) in accordance with the movement of the two slide arms 32 in the radial direction D. The two gripping portions 34 face each other in the horizontal direction X, separated by a gripping space S for gripping the workpiece 1, and are arranged so as to be symmetrical with respect to a first center line M1 extending in the horizontal direction Y when viewed from above (see FIGS. 3 and 4).

[0036] 3, each gripping portion 34 has a first gripping member 35 and a second gripping member 36 arranged side by side in a horizontal plane so as to be able to come into contact with the outer peripheral surface 1a (see FIG. 1) of the workpiece 1. In this embodiment, two second gripping members 36 are arranged side by side on both sides of one first gripping member 35. In this case, each gripping portion 34 has a shape that is line-symmetrical with respect to a second center line M2 extending in the horizontal direction X when viewed from above.

[0037] The two gripping units 34 move in synchronization with the movement of the two slide arms 32. Specifically, the two gripping units 34 slide in the horizontal direction X with the same displacement amount relative to the gripping central axis M of the workpiece gripping mechanism unit 30. Here, the gripping central axis M is an imaginary line that passes through the intersection of the first center line M1 and the second center line M2 and extends in the vertical direction Z.

[0038] Here, the first position P1 of the slide arm 32 is set in advance as a position where, when the workpiece 1 is placed in the gripping space S between the two gripping parts 34, a gap is formed between the outer peripheral surface 1a of the workpiece 1 and the gripping parts 34. In contrast, the second position P2 of the slide arm 32 is set in advance as a position where the outer peripheral surface 1a of the workpiece 1 is gripped with a predetermined gripping force by the cooperation of the two gripping parts 34.

[0039] The non-gripping position Q1 of the gripping part 34 is a position when the slide arm 32 is at the first position P1, and is set in advance as a position where a gap is formed between the slide arm 32 and the outer peripheral surface 1a of the workpiece 1. In contrast, the gripping position Q2 of the gripping part 34 is a position when the slide arm 32 is at the second position P2, and is set in advance as a position where the slide arm 32 cooperates with the other gripping part 34 to grip the outer peripheral surface 1a of the workpiece 1 with a predetermined gripping force.

[0040] It is preferable that the first position P1 and second position P2 of the slide arm 32 and the non-gripping position Q1 and gripping position Q2 of the gripping portion 34 are all set appropriately depending on the outer diameter and material of the work 1 to be delivered.

[0041] The first gripping member 35 is attached to the first bracket 32a of the slide arm 32 so as to be rotatable about a mounting shaft 35a extending in the vertical direction Z. The first gripping member 35 has a concave (substantially V-shaped) shape with respect to the gripping space S for the workpiece 1, so that the shape of the opposing portion facing the gripping space S for the workpiece 1 conforms to the outer peripheral surface 1a of the workpiece 1. This concave shape is not limited to a substantially V-shape and may be, for example, a curved shape. If the first gripping member 35 is rotatable, it can automatically fine-tune the orientation of the first gripping member 35 to conform to the outer peripheral surface 1a of the workpiece 1 in response to the reaction force received from the workpiece 1. Note that if this function is not necessary, a structure in which the first gripping member 35 is fixed to the slide arm 32 may be adopted.

[0042] The second gripping member 36 is attached to the slide arm 32 via a connecting member 37. The connecting member 37 is attached to the second bracket 32b of the slide arm 32 so as to be rotatable about a mounting shaft 37a extending in the vertical direction Z. The second gripping member 36 is a cylindrical gripping roller attached to the connecting member 37 so as to be rotatable about a rotation shaft 36a extending in the vertical direction Z.

[0043] The second gripping member 36 is arranged to contact the outer peripheral surface 1a of the workpiece 1 in preference to the first gripping member 35 when the two gripping portions 34 slide from the non-gripping position Q1 to the gripping position Q2. This second gripping member 36 is configured to move along the outer peripheral surface 1a of the workpiece 1 in response to the reaction force received from the workpiece 1 when the gripping central axis M is misaligned with the workpiece central axis L. This adjusts the position of the gripping portions 34 in the horizontal plane relative to the workpiece 1 so that the gripping central axis M overlaps the workpiece central axis L. Furthermore, this second gripping member 36 is configured to elastically deform until both the first gripping member 35 and the second gripping member 36 contact the outer peripheral surface 1a of the workpiece 1.

[0044] The elastic member 38 is provided between the slide arm 32 and the connecting member 37, and has the function of applying an elastic biasing force to the connecting member 37 toward the gripping space S. Therefore, the second gripping member 36 is attached to the slide arm 32 via the elastic member 38 so as to be elastically displaceable. The second gripping member 36 is configured to be elastically displaced toward the slide arm 32 in response to the reaction force received from the workpiece 1 when it comes into contact with the outer peripheral surface 1a of the workpiece 1.

[0045] 4. Structure of the hanging chain 40 3, the hanging chain 40 is for suspending the workpiece gripping mechanism 30 from the movable base 28 of the main body 20 so that it can swing freely within a horizontal plane. When the workpiece gripping mechanism 30 grips the outer peripheral surface 1a of the workpiece 1, the hanging chain 40 follows the positional deviation in the horizontal directions X and Y relative to the workpiece 1, and allows the gripping central axis M (see FIG. 4) to move within the horizontal plane so as to overlap with the workpiece central axis L (see FIG. 1).

[0046] In this embodiment, the number of hanging chains 40 is four to improve the hanging stability of the workpiece gripping mechanism 30. The number of hanging chains 40 may be changed to a number other than four as needed. Furthermore, this embodiment illustrates a case where the hanging chain 40 is a sling chain of a known structure formed by continuously connecting multiple circular chains. A sling chain has the advantage of being excellent for suspending the workpiece gripping mechanism 30 while increasing the degree of freedom of movement in a horizontal plane. However, the hanging chain 40 is not limited to a sling chain, and may be formed of a hanging device such as a wire rope, a fiber rope, or a fiber belt.

[0047] 5. Control system of workpiece transport device 101 5, a control unit 51 is mounted on a control panel 50. The control unit 51 is electrically connected to each of the control objects, namely, the traveling motor 14, the traveling motor 21, the lifting motor 26, and the gripping cylinder 33, and outputs control signals to the control objects.

[0048] 6.Transportation of workpiece 1 Next, the transport operation of transporting the workpiece 1 using the workpiece transport device 101 configured as described above will be described with reference to Figs. 6 to 14. This transport operation is possible by sequentially executing each step in the flowchart of Fig. 6. Note that, if necessary, other steps may be added, or at least one step may be divided into multiple steps.

[0049] 6-1. Alignment of the workpiece gripping mechanism 30 The first step S101 in FIG. 6 is a step for aligning the workpiece gripping mechanism 30 with respect to the workpiece 1. In this first step S101, the operator operates a predetermined operating device (not shown) for driving the travel motors 14 and 21. As a result, the slider 13 is caused to travel in the horizontal direction Y from the initial position by the travel motor 14, and the main body 20 is caused to travel in the horizontal direction X from the initial position by the travel motor 21, so that the workpiece gripping mechanism 30 is aligned with the workpiece 1. According to this first step S101, the workpiece gripping mechanism 30 moves in conjunction with the movement of the slider 13 and the main body 20, and is roughly aligned with the workpiece 1. Note that in this first step S101, the gripping central axis M of the workpiece gripping mechanism 30 does not need to overlap with the workpiece central axis L for the following reason (see FIGS. 7 and 8).

[0050] That is, the work transportation device 101 of this embodiment is not equipped with high-precision devices such as a position sensor and a measurement correction device. Therefore, deviation of the gripping central axis M from the workpiece central axis L may occur due to variations in the position of the workpiece 1 or differences in size. Therefore, instead of a position sensor and a measurement correction device, the work transportation device 101 is equipped with a tracking function (described later) that causes the workpiece gripping mechanism unit 30 to track this position deviation. With this tracking function, it is sufficient that the gripping central axis M does not overlap the workpiece central axis L at the stage when the first step S101 is performed. Of course, this does not exclude the possibility that the gripping central axis M overlaps the workpiece central axis L at the stage when the first step S101 is performed.

[0051] 6-2. Lowering operation of the workpiece gripping mechanism 30 6 is a step of lowering the workpiece gripping mechanism 30 following the first step S101. In this second step S102, the worker operates a predetermined operating device (not shown) for driving the lifting motor 26 so that the lifting chain 27 pulls down the movable base 28. In conjunction with the lifting chain 27 pulling down the movable base 28, the hanging chain 40 and the workpiece gripping mechanism 30 lower together from their initial positions. As a result, as shown in FIG. 9, the uppermost workpiece 1 is placed in the gripping space S between the two gripping parts 34 of the workpiece gripping mechanism 30 with the gripping central axis M misaligned with the workpiece central axis L.

[0052] 6-3. Gripping operation of the workpiece gripping mechanism 30 6 is a step following the second step S102 in which the workpiece gripping mechanism 30 performs a gripping operation. In this third step S103, the operator operates a predetermined operating device (not shown) for driving the gripping cylinders 33 so that the two gripping parts 34 slide from the non-gripping position Q1 (see FIG. 9) to the gripping position Q2 (see FIG. 10). As a result, as shown in FIG. 10, the two gripping parts 34 approach each other toward the gripping central axis M by the gripping cylinders 33 and grip the outer peripheral surface 1a of the workpiece 1 from the outside in the radial direction D.

[0053] At this time, the hanging chain 40 allows the workpiece gripping mechanism 30 to move in accordance with the positional deviation in the horizontal directions X and Y relative to the workpiece 1, so that the gripping central axis M overlaps the workpiece central axis L. Therefore, due to the aforementioned tracking function, the workpiece gripping mechanism 30 moves toward the workpiece 1 in the horizontal plane while pulling the hanging chain 40 in conjunction with the sliding movement of the two grippers 34 toward the gripping position Q2. As a result, the gripping central axis M overlaps the workpiece central axis L. At this time, the state of the hanging chain 40 changes from extending perpendicularly in the vertical direction Z to extending obliquely relative to the vertical direction Z. Meanwhile, the movable base 28 is suspended by the lifting chain 27, restricting its movement in the horizontal direction X. Therefore, the movable base 28 barely moves, and only the workpiece gripping mechanism 30 moves in accordance with the position of the workpiece 1.

[0054] In this embodiment, the sliding movement of the two slide arms 32 is performed using the gripping cylinder 33, but instead of this, an actuator such as an electric motor may be used instead of the cylinder.

[0055] Here, a detailed description will be given of the gripping operation of the workpiece gripping mechanism 30 in the third step S103. This gripping operation is roughly divided into a first stage to a third stage.

[0056] 11, in the first stage of the gripping operation in the third step S103, first, the two gripping units 34 are slid toward the gripping position Q2 until they interfere with the outer peripheral surface 1a of the workpiece 1 from both sides in the radial direction D. Because the workpiece gripping mechanism 30 is allowed to move in the horizontal plane by the hanging chains 40, the positional deviation in the horizontal direction X of the gripping central axis M relative to the workpiece central axis L is eliminated. At this time, one of the two second gripping members 36 in each gripping unit 34 comes into contact with the outer peripheral surface 1a of the workpiece 1.

[0057] As shown in FIG. 12, in the second stage of the gripping operation in the third step S103, the two slide arms 32 are slid so that the two gripping units 34 approach each other even more closely. At this time, movement of the workpiece gripping mechanism 30 is permitted within the horizontal plane. As a result, the second gripping member 36, which is in contact with the outer peripheral surface 1a of the workpiece 1, rotates about the rotation axis 36a due to friction with the outer peripheral surface 1a. The two gripping units 34 move in the direction of arrow Y1 due to the second gripping member 36's movement to follow the shape of the outer peripheral surface 1a of the workpiece 1. Therefore, the horizontal positional deviation of the gripping central axis M relative to the workpiece central axis L is corrected, and the gripping central axis M overlaps the workpiece central axis L. At this time, in each gripping unit 34, both of the two second gripping members 36 are in contact with the outer peripheral surface 1a of the workpiece 1, while the first gripping member 35 is not yet in contact with the outer peripheral surface 1a of the workpiece 1.

[0058] 13, in the third stage of the gripping operation in the third step S103, the two gripping parts 34 are slid to gripping position Q2 so that the two gripping parts 34 approach each other even more. At this time, the two connecting members 37 of each gripping part 34 rotate about the mounting shaft 37a against the elastic biasing force of the elastic member 38 in accordance with the load that the second gripping member 36 receives from the workpiece 1 side until the first gripping member 35 contacts the outer peripheral surface 1a of the workpiece 1. Therefore, in each gripping part 34, the first gripping member 35 and the two second gripping members 36 all contact the outer peripheral surface 1a of the workpiece 1. This allows the two gripping parts 34 to grip the outer peripheral surface 1a of the workpiece 1 from both sides in the radial direction D.

[0059] 6-4. Lifting operation of the workpiece gripping mechanism 30 The fourth step S104 in FIG. 6 is a step following the third step S103, in which the workpiece gripping mechanism 30 is raised. This fourth step S104 is a step in which control is reversed from that of the second step S102, and as shown in FIG. 14, the workpiece gripping mechanism 30, gripping the topmost workpiece 1, is raised to a predetermined height by the lifting operation of the lifting chains 27 to lift the movable base 28. This lifts only the topmost workpiece 1. At this time, the state of the hanging chains 40 returns from a state in which it was extended obliquely with respect to the vertical direction Z to a state in which it was extended perpendicular to the vertical direction Z. Therefore, as the workpiece gripping mechanism 30 is raised, it returns to the position it was in before gripping the workpiece 1 with respect to the movable base 28 according to the principle of a pendulum.

[0060] 6-5. Transfer operation of workpiece gripping mechanism 30 to destination 6 is a step following the fourth step S104 in which the workpiece gripping mechanism 30 is moved to the destination. In this fifth step S105, the workpiece gripping mechanism 30 is moved to the destination of the workpiece 1 by appropriately combining the traveling motion of the slider 13, the traveling motion of the main body 20, and the lowering motion of the workpiece gripping mechanism 30, as described above.

[0061] 6-6. Release of gripping action of workpiece gripping mechanism 30 6 is a step following the fifth step S105 in which the workpiece gripping mechanism 30 performs a release operation. In this sixth step S106, the two gripping units 34 are slid from the gripping position Q2 to the non-gripping position Q1 by control reverse to the gripping operation in the third step S103. This releases the grip of the outer peripheral surface 1a of the workpiece 1 by the two gripping units 34, completing the transport of the workpiece 1 to its destination.

[0062] 6-7. Returning operation of the workpiece gripping mechanism 30 to its initial position 6 is a step following the sixth step S106 in which the workpiece gripping mechanism 30 is returned to its initial position. In this seventh step S107, the workpiece gripping mechanism 30 is returned to its initial position by appropriately combining the traveling motion of the slider 13, the traveling motion of the main body 20, and the lifting motion of the workpiece gripping mechanism 30, as described above. Then, the workpiece gripping mechanism 30 is prepared for the transfer of the next workpiece 1 to be transferred.

[0063] 7. Action and Effects According to the above-described embodiment, the following effects can be obtained.

[0064] In the workpiece transport device 101, the workpiece gripping mechanism 30, which can grip the outer peripheral surface 1a of the workpiece 1 from the outside in the radial direction D, is suspended from the movable base 28 of the main body 20 by a hanging chain 40 so as to be swingable within a horizontal plane. The hanging chain 40 is configured to allow the gripping central axis M of the workpiece gripping mechanism 30 to move within the horizontal plane so as to overlap with the workpiece central axis L when the workpiece gripping mechanism 30 grips the outer peripheral surface 1a of the workpiece 1. Therefore, if the gripping central axis M is misaligned horizontally with respect to the workpiece central axis, the workpiece gripping mechanism 30 suspended from the hanging chain 40 moves within the horizontal plane to eliminate this misalignment.

[0065] According to the above configuration, horizontal positional deviation of the workpiece gripping mechanism 30 relative to the workpiece 1 can be eliminated by using a simple hanging structure with the hanging chain 40, without using high-precision equipment such as position sensors and measurement and correction devices. When high-precision equipment is used, there is a problem of susceptibility to environmental changes (e.g., illuminance), but since no high-precision equipment is used, this problem does not arise. Furthermore, by using hanging members instead of position sensors and measurement and correction devices, the number of parts used can be reduced, thereby making it possible to reduce both initial and running costs.

[0066] Therefore, it is possible to provide a workpiece transport device 101 that has a simple structure and can keep costs low.

[0067] According to the workpiece transport device 101, the workpiece gripping mechanism 30 is configured by the guide frame 31, two slide arms 32, and two gripping parts 34, so that the structure of the workpiece gripping mechanism 30 can be simplified.

[0068] According to the workpiece conveyance device 101, when the gripping unit 34 slides from the non-gripping position Q1 to the gripping position Q2, the second gripping member 36, which is elastically displaceably attached to the slide arm 32 via the elastic member 38, comes into contact with the outer peripheral surface 1 a of the workpiece 1 before the first gripping member 35. At this time, if the gripping central axis M is misaligned with the workpiece central axis L, the second gripping member 36 moves along the outer peripheral surface 1 a of the workpiece 1 in response to the reaction force received from the workpiece 1, so that the gripping central axis M overlaps the workpiece central axis L. In this way, the second gripping member 36 can be used to absorb misalignment of the gripping central axis M in the horizontal plane with respect to the workpiece central axis L. Then, the second gripping member 36 elastically displaces until both the first gripping member 35 and the second gripping member 36 come into contact with the outer peripheral surface 1 a of the workpiece 1, thereby allowing both the first gripping member 35 and the second gripping member 36 to grip the outer peripheral surface 1 a of the workpiece 1.

[0069] According to the workpiece transport device 101, by employing a rotary gripping roller as the second gripping member 36, the gripping roller rotates about the rotation axis 36a in response to the reaction force received from the workpiece 1 when it comes into contact with the outer circumferential surface 1a of the workpiece 1, thereby moving smoothly along the outer circumferential surface 1a of the workpiece 1. Therefore, the function required of the second gripping member 36 can be realized by the rotary gripping roller.

[0070] According to the workpiece transport device 101, by increasing the number of second gripping members 36 by arranging two second gripping members 36 side by side on both sides of the first gripping member 35, it is possible to improve the effect of absorbing positional deviation in the horizontal plane of the gripping central axis M relative to the workpiece central axis L. Furthermore, gripping the outer peripheral surface 1a of the workpiece 1 with one first gripping member and the two second gripping members 36 on either side of it can improve gripping stability.

[0071] Next, other embodiments related to the above-described embodiment 1 will be described with reference to the drawings. In the other embodiments, the same elements as those in embodiment 1 are denoted by the same reference numerals, and the description of the same elements will be omitted.

[0072] (Embodiment 2) 15, the workpiece gripping mechanism unit 30A of the workpiece transfer device 102 of the second embodiment differs from that of the first embodiment in that there is only one second gripping member 36 in each gripping unit 34. Furthermore, when the two gripping units 34 are viewed from above, the second gripping member 36 of one gripping unit 34 and the second gripping member 36 of the other gripping unit 34 are arranged in positions symmetrical to each other with respect to the gripping central axis M.

[0073] The other configurations are the same as those in the first embodiment.

[0074] According to the workpiece transport device 102, by reducing the number of second gripping members 36 in each gripping unit 34 of the workpiece gripping mechanism unit 30A, it is possible to simplify the structure of each gripping unit 34. Furthermore, even if the number of second gripping members 36 is one, it is possible to ensure at least the function of adjusting the position of the gripping unit 34 in the horizontal plane relative to the workpiece 1 so that the gripping central axis M overlaps the workpiece central axis L, by cooperation between the second gripping member 36 of one gripping unit 34 and the second gripping member 36 of the other gripping unit 34.

[0075] In addition, the same effects as those in the first embodiment are achieved.

[0076] (Embodiment 3) 16, the workpiece gripping mechanism 30B of the workpiece transfer device 103 of the third embodiment differs from that of the first embodiment in that the number of gripping parts 34 is three. The three gripping parts 34 are arranged at equal intervals in the circumferential direction.

[0077] The other configurations are the same as those in the first embodiment.

[0078] According to the workpiece conveying device 103, by increasing the number of gripping portions 34 in the workpiece gripping mechanism unit 30B to three, it is possible to improve the gripping stability of the outer peripheral surface 1a of the workpiece 1 compared to when the number of gripping portions 34 is two.

[0079] In addition, the same effects as those in the first embodiment are achieved.

[0080] 8. Modifications The present invention is not limited to the above-described embodiment, and various applications and modifications are possible without departing from the scope of the present invention. For example, the following embodiments can be implemented by applying the above-described embodiment.

[0081] In the above embodiment, an example is given of using a rotating gripping roller as the second gripping member 36, but instead, the second gripping member 36 may be fixed to the connecting member 37, and the second gripping member 36 itself may be made of a material with low surface roughness, or the second gripping member 36 may be coated with a coating material with low sliding resistance, thereby realizing a copying operation that copies the shape of the outer peripheral surface 1a of the workpiece 1.

[0082] In the above embodiment, a structure in which the gripping portion 34 has the first gripping member 35 and the second gripping member 36 has been exemplified, but instead, a structure in which the gripping portion 34 has only the first gripping member 35 may be adopted.

[0083] In the above embodiment, the workpiece 1 is a tire, but the workpiece 1 is not limited to a tire. The workpiece 1 may be any type of workpiece with a circular outer periphery. For example, a cylindrical workpiece such as a drum may be transported. [Explanation of symbols]

[0084] 1...workpiece, 1a...outer peripheral surface, 10...frame, 20...main body, 28...movable base, 30, 30A, 30B...workpiece gripping mechanism, 31...guide frame, 32...slide arm, 34...gripping portion, 35...first gripping member, 36...second gripping member, 36a...rotating shaft, 38...elastic member, 40...hanging chain (hanging member), 41...lower end portion, 101, 102, 103...workpiece transport device, D...radial direction, L...workpiece central axis, M...gripping central axis, Q1...non-gripping position, Q2...gripping position, X, Y...horizontal direction, Z...up and down direction

Claims

1. A workpiece conveying device that conveys a workpiece having a circular outer circumferential surface, A stand and a main body portion having a movable base that is movable in the horizontal direction of the pedestal and that is movable up and down in the vertical direction of the pedestal; a workpiece gripping mechanism capable of gripping the outer peripheral surface of the workpiece from the outside in the radial direction in a state in which the workpiece is placed so that the workpiece central axis is aligned in the vertical direction; a hanging member that hangs the workpiece gripping mechanism from the movable base of the main body so that the workpiece gripping mechanism can swing freely within a horizontal plane; Equipped with the hanging member allows the gripping central axis to move in a horizontal plane so as to overlap with the workpiece central axis, following the horizontal positional deviation of the gripping central axis with respect to the workpiece central axis when the workpiece gripping mechanism grips the outer peripheral surface of the workpiece. Work transport device.

2. 2. The workpiece transport device according to claim 1, wherein the workpiece gripping mechanism comprises a guide frame attached to a lower end of the hanging member, a plurality of slide arms guided in the radial direction by the guide frame, and a gripping portion provided on each of the plurality of slide arms so as to slide between a non-gripping position and a gripping position in accordance with the radial movement.

3. The gripping unit has a first gripping member and a second gripping member arranged side by side in a horizontal plane so as to be able to contact the outer circumferential surface of the workpiece, the second gripping member is attached to the slide arm via an elastic member so as to be elastically displaceable, and is configured to contact the outer peripheral surface of the workpiece preferentially over the first gripping member when the gripping portion slides from the non-gripping position toward the gripping position, 3. The workpiece transportation device according to claim 2, wherein when the gripping central axis is misaligned with the workpiece central axis, the second gripping member moves along the outer peripheral surface of the workpiece in response to a reaction force received from the workpiece until the gripping central axis overlaps with the workpiece central axis, and is configured to elastically deform until both the first gripping member and the second gripping member come into contact with the outer peripheral surface of the workpiece.

4. The workpiece transport device according to claim 3 , wherein the second gripping member is a gripping roller that is rotatable about a rotation axis that extends along the vertical direction.

5. 5. The workpiece transport device according to claim 3, wherein the gripping portion of the workpiece gripping mechanism is configured such that the second gripping members are arranged side by side on both sides of the first gripping member.

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