Transport device

Abstract

A transport device (200) comprises a plurality of carriers (100) that are independently drive-controlled by a linear motor and travel on the same rail (201) so as to transport an object (300) to be transported. The carriers (100) each comprise: a carrier body (1) that holds the object (300) to be transported and travels along the rail (201); and a buffering mechanism (4) that is attached to the carrier body (1) and buffers the impact force generated when a collision with an adjacent carrier (100) has occurred. The buffering mechanism (4) includes: a buffering protrusion part (5) that protrudes toward the carrier (100) positioned in front of the carrier (100) having said protrusion part (5); and a buffering reception part (6) that receives the buffering protrusion part (5) of the carrier (100) traveling behind the carrier (100) having said buffering reception part (6). The buffering reception part (6) includes a recessed reception surface section (60) that is recessed toward the inside of the carrier body (1) and into which the buffering protrusion part (5) of the carrier (100) traveling behind enters.

Description

Conveyor

[0001] The present disclosure relates to a conveying device including a plurality of carriers for conveying an object.

[0002] Conventionally, conveying devices have been known that include multiple carriers that travel on the same rail to transport objects. The multiple carriers are independently driven and controlled by linear motors. In the conveying device, because the multiple carriers travel independently on the rail, it is necessary to mitigate the impact force when adjacent carriers collide with each other. For example, Patent Document 1 discloses a carrier braking mechanism that uses a braking device to brake a runaway carrier traveling along a rail. This carrier braking mechanism includes a stopper member made of a buffer material provided at the end of the rail and a clamping mechanism that clamps a plate member attached to the underside of the carrier. The plate member of the traveling carrier is clamped by the clamping mechanism, and the friction causes the carrier to decelerate and collide with the stopper member, thereby mitigating the impact force on the carrier.

[0003] Japanese Patent Publication No. 61-247563

[0004] However, the technology disclosed in Patent Document 1 is a configuration for stopping a runaway carrier at the end of the rail, and is not a configuration for mitigating the impact force when adjacent carriers collide with each other.

[0005] The present disclosure has been made in view of the above, and aims to provide a transport device that can reduce the impact force when adjacent carriers collide with each other.

[0006] In order to solve the above-mentioned problems and achieve the object, the conveying device according to the present disclosure includes a plurality of carriers that are independently driven and controlled by linear motors and travel on the same rail to convey objects. The carriers include a carrier body that holds the objects and travels along the rail, and a buffer mechanism attached to the carrier body that absorbs impact forces when adjacent carriers collide. The buffer mechanism has a buffer protrusion that protrudes toward the carrier located in front, and a buffer receiving portion that receives the buffer protrusion of the carrier traveling behind. The buffer receiving portion has a concave receiving surface that is recessed toward the inside of the carrier body and fits into the buffer protrusion of the carrier traveling behind.

[0007] The transport device according to the present disclosure has the advantage that when adjacent carriers collide with each other, the impact force can be alleviated.

[0008] 4 is a graph showing the time history waveform of the impact force in the dynamic model shown in FIG. 4; FIG. 5 is a diagram showing the force vectors of the impact force, inertia force, and bearing reaction force in a collision between carriers in the conveying device according to the first embodiment; 1 is a top view showing an example in which the conveyance device according to the third embodiment runs on a rail that curves to the right; FIG. 2 is a perspective view showing a carrier constituting the conveyance device according to the second embodiment; FIG. 3 is an explanatory view showing a carrier constituting the conveyance device according to the second embodiment, and illustrating the force vectors of the impact force and the inertial force when the carriers collide; FIG. 4 is a top view showing a state in which the conveyance device according to the third embodiment runs on a straight rail;

[0009] Hereinafter, a conveying device according to an embodiment of the present disclosure will be described in detail with reference to the drawings.

[0010] First Embodiment Fig. 1 is a top view schematically showing a state in which a conveying device according to a first embodiment is traveling along a linear rail. Note that Fig. 1 does not show a conveyed object 300 placed on the upper surface of the carrier 100. Fig. 2 is a perspective view schematically showing the carrier 100 constituting the conveying device 200 according to the first embodiment. In the drawing, the Z axis is the vertical direction, the X axis is the direction along the rail 201, and the Y axis is the direction perpendicular to the Z axis and the X axis.

[0011] As shown in FIGS. 1 and 2 , the conveying device 200 includes multiple carriers 100 driven by linear motors and traveling on the same rail 201 to convey an object 300. The multiple carriers 100 are not connected to one another, but travel independently on the rail 201 by drive control of the linear motors and stop at a target position. The linear motor is composed of a mover provided on the carrier 100 and a stator provided on the stationary rail 201. The carriers 100 are independently driven and controlled by controlling the current flowing through the coils of the stator. Note that the conveying device 200 is not limited to the configuration in which three carriers 100 are arranged on the rail 201 shown in FIG. 1 , but may be configured with two carriers 100 arranged on the rail 201, or with four or more carriers 100 arranged on the rail 201.

[0012] The carrier 100 includes a carrier body 1, rollers 2, a mover 3, and a buffer mechanism 4. The carrier body 1 holds a transported object 300 and travels along a rail 201. The carrier body 1 has a first surface 10 constituting the upper surface, a second surface 11 constituting the lower surface, and a third surface 12 connecting the first surface 10 and the second surface 11 and constituting a side surface. The carrier body 1 is concave between the first surface 10, the second surface 11, and the third surface 12. The carrier body 1 travels along the rail 201 by disposing the rail 201 inside the concave. The transported object 300 is placed on the upper surface of the first surface 10 of the carrier body 1 via the buffer mechanism 4. The shape of the carrier body 1 is not limited to the concave shape shown in the figure and may be, for example, an H-shape or a cylindrical shape. In short, the carrier body 1 may have any other shape as long as it is configured to hold the transported object 300 and run along the rail 201.

[0013] As shown in Fig. 2, the rollers 2 are attached to the first surface 10 and the second surface 11 of the carrier body 1, for example. The rollers 2 are attached to the carrier body 1 via rolling bearings (not shown). As shown in Fig. 1, the rollers 2 attached to the first surface 10 are, for example, four rollers 2 provided on the concave inner surface so as to sandwich the rail 201 from both sides. The rollers 2 attached to the second surface 11 are, for example, two rollers 2 provided side by side on the concave outer surface so as to roll along the rail 201. The positions and number of the rollers 2 are not limited to the configuration shown in the figure, and may be changed as appropriate depending on the shape of the carrier body 1.

[0014] The mover 3, together with a stator (not shown), constitutes a linear motor. The mover 3 has a mover core 30 made of a magnetic material and a plurality of permanent magnets (not shown) arranged with alternating polarities. The permanent magnets are arranged on the back surface of the mover core 30. A stator (not shown) is arranged on the rail 201. The stator has a stator core made of a magnetic material arranged to face the mover 3, and a coil attached to the stator core. The carrier 100 is driven by generating a propulsive force by controlling the current flowing through the stator coil. In addition, a position sensor is attached to the carrier 100, and the running speed of the carrier 100 is controlled by controlling the current to the stator coil based on feedback of the position of the carrier 100, thereby controlling the positioning of the carrier 100 to a target position.

[0015] 1, the buffer mechanism 4 is attached to the carrier body 1 and serves to absorb the impact force when adjacent carriers 100 collide with each other. The buffer mechanism 4 includes a buffer protrusion 5 that protrudes toward the carrier 100 located in front, and a buffer receiving portion 6 that receives the buffer protrusion 5 of the carrier 100 traveling behind. The buffer protrusion 5 is made of an elastic member such as vibration-isolating rubber, and abuts against the buffer receiving portion 6 of the carrier 100 located in front.

[0016] As shown in FIG. 2 , the buffer receiving portion 6 is made of an elastic material such as vibration-isolating rubber and is attached to the upper surface of the first surface 10 of the carrier body 1. The transported object 300 is held on the first surface 10 of the carrier body 1 via the buffer receiving portion 6 of the buffer mechanism 4. That is, the buffer receiving portion 6 is installed on the upper surface of the carrier body 1 near the center of gravity of the entire structure including the transported object 300 and the carrier 100. The buffer receiving portion 6 is formed as a rectangular cylinder, for example, with one of its four sides recessed toward the inside of the carrier body 1, and has a concave receiving surface 60 into which the buffer protrusion 5 of the carrier 100 traveling behind it fits. In the transport device 200, the length of the buffer protrusion 5 is longer than the depth of the recess in the receiving surface 60. This allows the transport device 200 to receive the buffer protrusion 5 with the buffer receiving portion 6 before the carrier bodies 1 of the front and rear carriers 100 collide with each other. Furthermore, in the conveying device 200 of embodiment 1, the buffer protrusion 5 is configured to fit into the receiving surface 60 of the buffer receiving portion 6, so that the buffer protrusion 5 and the buffer receiving portion 6 do not interfere with each other, and the carrier 100 located in front and the carrier 100 traveling behind can be brought close to each other, thereby widening the positioning range of the carrier 100 and enabling the transported item 300 to be transported to the target position.

[0017] FIG. 3 is a top view schematically illustrating a state in which the conveying device according to the first embodiment is traveling along a curved rail. As shown in FIG. 3 , when the conveying device 200 travels with multiple carriers 100 along a curved rail 202, the yawing (rotation around the Z-axis) angles of the front and rear carriers 100 are different. Therefore, the buffer protrusions 5 of the rear carrier 100 do not abut against the groove bottom of the receiving surface 60 of the buffer receiving portion 6 of the front carrier 100, but the abutment position moves and abuts against the side wall surface connecting the concave opening end to the groove bottom. Therefore, the side wall surface of the receiving surface 60 of the buffer receiving portion 6 is curved to correspond to the curve of the curved rail 202. This allows the tip of the buffer protrusions 5 to abut against the curved side wall surface of the receiving surface 60 even when the conveying device 200 travels along the curved rail 202. Therefore, the buffer protrusions 5 can abut against the buffer receiving portion 6 before adjacent carrier bodies 1 collide, thereby mitigating the impact force.

[0018] 4 is an explanatory diagram showing a dynamic model of carrier collision in the conveyance device according to the first embodiment. In FIG. 4, the components are represented as follows: the wall on the left side of the page is the front carrier 100A, the square box on the right side of the page is the rear carrier 100B, and the schematic diagram of the spring is the buffer protrusion 5. In addition, the schematic diagram of the roller supporting the rear carrier 100B from below is the roller 2, and the floor surface is the rail 201.

[0019] 5 is a graph showing the time history waveform of the impact force in the dynamic model shown in FIG. 4. The vertical axis represents the impact force f when adjacent carriers 100 collide with each other. ｃ 5. The horizontal axis represents time t. From time 0 to t1 shown in FIG. 5, the buffer protrusions 5 of the rear carrier 100B do not come into contact with the front carrier 100A. Therefore, the impact force applied from the buffer protrusions 5 to the carriers 100A and 100B is zero. Then, from t1, which is the moment when the buffer protrusions 5 of the rear carrier 100B come into contact with the front carrier 100A, the impact force increases and reaches a maximum value, then decreases and becomes zero again at time t2. The maximum value of the impact force is midway between t1 and t2.

[0020] If the buffer protrusion 5 is within the range of elastic deformation, the spring force generates a repulsive force proportional to the amount of compression of the cushion. Therefore, if friction and damping are ignored, the waveform of the impact force will be a half-sine wave. That is, when the rear carrier 100B travels at a constant speed v and collides with the stationary front carrier 100A, a repulsive force with a half-sine wave shape as shown in Figure 5 is generated. At this time, if the traveling speed of the rear carrier 100B is v and its mass is m, the momentum is mv, and the impact force f ｃ Since it is equal to the time integral from time t1 to time t2, it can be expressed as equation (1).

[0021]

[0022] Impact force f ｃ Since f is a half sine wave, it can be expressed as in equation (2). ｎ is Equation (3).

[0023]

[0024]

[0025] Substituting equation (3) into equation (2) and letting the acceleration of the rear carrier 100B be α, f ｃ =mα, and by substituting this into equation (1) and calculating the integral, equation (4) is obtained.

[0026]

[0027] where α ｍａｘ is the maximum value of acceleration α. ​​By eliminating m from both sides of equation (4) and rearranging, equation (5) is obtained.

[0028]

[0029] where ω ｎ is the natural angular frequency, and ω ｎ = 2πf ｎ It is expressed as:

[0030] The maximum impact force applied to the carrier 100 is α ｍａｘ Therefore, if the buffer protrusion 5 is made soft, the natural angular frequency ω ｎ The value of becomes smaller, and the acceleration α and impact force f ｃ For example, the vibration-isolating rubber of the buffer protrusion 5 is the same as that of a vibration-isolating rubber stopper (model: RE4000A5) manufactured by NOK Corporation, and the protrusion height is 50 mm, the cushion bottom width is 29 mm, and the cushion tip width is 13 mm. When the mass m of the carrier 100B is 1 kg, the natural frequency f ｎ is 19.2 Hz. In addition, the maximum value α of the impact acceleration when the carrier 100B collides with the carrier 100B at a velocity v of 1 m / s is ｍａｘ is 6.2G. Also, the impact force f ｃ So, 6.2 kgf = 6.2 x 9.8 = 60.8 N.

[0031] 6 is an explanatory diagram showing the force vectors of the impact force, inertia force, and bearing reaction force when carriers collide with each other in the conveying device according to the first embodiment. Fig. 6 shows the force vectors of the impact force a, the inertia force b, and the bearing reaction force c when the carrier 100 located in front receives impact acceleration from another carrier 100 traveling from behind. The symbol of a circle with a black and white cross in Fig. 6 indicates the combined center of gravity of the carrier 100 and the conveyed object 300.

[0032] The center of gravity of the entire system, including the load 300 and the carrier 100, is located at the base of the arrow representing the inertial force b, and is shifted upward on the plane of FIG. 6 due to the mass of the load 300 (not shown). The impact force a and the inertial force b are equal in magnitude but directed in opposite directions, maintaining balance in the X direction along the rail 201. The impact force a and the inertial force b are not on the same line, and a moment force with the distance between the impact force a and the inertial force b as the moment arm acts on the carrier 100. A bearing reaction force c is generated to balance this moment force. The bearing reaction force c acts perpendicular to the track of the rail 201 because the roller 2 is supported on the carrier 100 by a rolling bearing (not shown), and the rotational sliding resistance is negligibly small. If the bearing-to-bearing distance that generates bearing reaction force c is doubled relative to the distance between impact force a and inertia force b, then bearing reaction force c will be 3.1 kgf, or 30.4 N, which is half the impact load of 6.2 kgf. If bearing reaction force c can be reduced in this way, even if a small ball bearing with a diameter of about 10 mm and a static load rating of 218 N is used as the rolling bearing, bearing reaction force c will be below the static load rating, and the bearing life will be maintained long. In other words, the moment force of impact force a and inertia force b can be reduced, and the impact load on the rolling bearings that make up carrier 100 can be reduced, allowing carrier 100 to be made smaller and its mechanical life to be extended.

[0033] 7A and 7B are top views of a modified example of the conveyance device according to the first embodiment, showing the case where the conveyance device runs on a rail that curves to the left. FIG. 8A and 8B are top views of a modified example of the conveyance device according to the first embodiment, showing the case where the conveyance device runs on a rail that curves to the right.

[0034] As shown in Figures 7 and 8, the transport device 200 is configured with a buffer receiving section 6 that allows the carrier 100 to travel along a left curve shown in Figure 7 and a right curve shown in Figure 8. The receiving surface section 60 of the buffer receiving section 6 has a pair of side wall surfaces extending from the concave opening end toward the groove bottom. One side wall surface of the receiving surface section 60 is formed in a curved shape corresponding to the curve of the rail 202 that curves left as shown in Figure 7, and the other side wall surface is formed in a curved shape corresponding to the curve of the rail 203 that curves right as shown in Figure 8. The carrier 100 moves along the rails 202 and 203 so that the buffer protrusions 5 are positioned outside the radius of curvature of the curves of the rails 202 and 203. As a result, even when the conveying device 200 is made to run along an S-shaped track consisting of a left-curving rail 202 and a right-curving rail 203, the tip of the buffer protrusion 5 can be abutted against the side wall surface of the receiving surface 60, so that the buffer protrusion 5 can abut against the buffer receiving surface 6 before the carriers 100 collide with each other, thereby mitigating the impact.

[0035] As described above, the conveying device 200 according to the first embodiment includes a plurality of carriers 100 that are independently driven and controlled by linear motors and travel on the same rail to convey the object 300. Each carrier 100 holds the object 300 and includes a carrier main body 1 that travels along the rail 201, and a buffer mechanism 4 that is attached to the carrier main body 1 and absorbs the impact force when adjacent carriers 100 collide with each other. The buffer mechanism 4 includes a buffer protrusion 5 that protrudes toward the carrier 100 located in front, and a buffer receiving portion 6 that receives the buffer protrusion 5 of a carrier 100 traveling behind. The buffer receiving portion 6 is recessed toward the inside of the carrier main body 1 and has a concave receiving surface 60 into which the buffer protrusion 5 of the carrier 100 traveling behind fits.

[0036] Therefore, the conveying device 200 according to the first embodiment is provided with a buffer mechanism 4 that buffers collisions between adjacent carriers 100, and is configured so that the buffer protrusions 5 of the carrier 100 traveling behind are received by the buffer receiving portions 6 of the carrier 100 located in front, thereby absorbing the impact force when adjacent carriers collide. Furthermore, the buffer receiving portions 6 are recessed toward the inside of the carrier main body 1, and have a concave receiving surface portion 60 into which the buffer protrusions 5 of the carrier 100 traveling behind fit. Therefore, the buffer protrusions 5 and the buffer receiving portions 6 do not interfere with each other, and the carrier 100 traveling in front and the carrier 100 traveling behind can be brought close to each other, thereby widening the positioning range of the carrier 100 and enabling the transported object 300 to be transported to the target position.

[0037] Second Embodiment Next, a conveying device 200 according to a second embodiment will be described. Fig. 9 is a perspective view schematically showing a carrier constituting the conveying device according to the second embodiment. Fig. 10 is a diagram schematically showing a carrier constituting the conveying device according to the second embodiment, and is an explanatory diagram showing the force vectors of the impact force and inertial force when carriers collide with each other. Note that the symbol of a circle with a black and white cross in Fig. 10 indicates the center of gravity of the carrier 100 and the conveyed object 300 combined.

[0038] As shown in Fig. 9, the transported object 300 is placed on the outer surface of the third surface 12 of the carrier body 1. That is, the transported object 300 is placed in a position facing the mover core 30. As shown in Fig. 10, when the transported object 300 is placed on the outer surface of the third surface 12 of the carrier body 1, the position of the center of gravity of the carrier 100 and the transported object 300 is approximately in the center of the carrier body 1, near the mover core 30 and the transported object 300. In this case, the buffer receiving portions 6 are installed at the upper and lower parts of the carrier body 1 at equal intervals from the position of the center of gravity of the carrier 100 and the transported object 300, with the position of the center of gravity of the carrier 100 and the transported object 300 as the center.

[0039] In the conveying device 200 according to the second embodiment, when a rear carrier 100 collides with a front carrier 100, an impact force a and an inertial force b are generated, as shown in FIG. 10 . The inertial force b is generated to balance the impact force a from the buffer protrusion 5. The impact force a from the buffer protrusion 5 is generated at the two buffer receiving portions 6 disposed above and below the center of gravity. At this time, the moment around the Y axis is balanced by the impact force a and the inertial force b. As a result, the conveying device 200 can reduce the load acting on the rollers 2 supporting the carrier main body 1 and the rolling bearings (not shown). Therefore, by using a small-diameter rolling bearing, the carrier 100 can be made smaller and the mechanical life of the carrier 100 can be extended.

[0040] Third Embodiment Next, a conveying device 200A according to a third embodiment will be described with reference to Fig. 11 to Fig. 14. Fig. 11 is a top view schematically showing a state in which the conveying device according to the third embodiment is caused to travel along a linear rail. Fig. 12 is a side view schematically showing a state in which the conveying device according to the third embodiment is caused to travel along a linear rail.

[0041] 11 and 12, the transport device 200A according to the third embodiment includes, in addition to the configuration of the first or second embodiment, a braking mechanism 7 that brakes the carrier 100 by sliding friction with the rail 201. The other configuration is the same as that of the first or second embodiment, and therefore detailed description will be omitted. For ease of explanation, in FIGS. 11 and 12, the carrier 100 located in the front is indicated as carrier 100A, and the carrier 100 traveling behind is indicated as carrier 100B.

[0042] The brake mechanism 7 includes a brake link 70, a pin 71, and a slider 72. As shown in FIG. 12 , when the carriers 100A, 100B are viewed from the side, the brake link 70 is formed in a substantially L-shape with a first flat portion 70a extending in the vertical direction and a second flat portion 70b extending in the traveling direction of the rail 201. The brake link 70 is supported rotatably in the vertical direction around a pin 71 provided at the vertical middle of the first flat portion 70a. The pin 71 is fixed to the carrier main body 1, for example. The slider 72 is attached to the second flat portion 70b of the brake link 70. The slider 72 moves in conjunction with the rotation of the brake link 70 and comes into contact with a rail base 201a, which is part of the rail 201, generating sliding friction. The slider 72 is not limited to a configuration in which it contacts the rail base 201 a, but may be configured to contact other locations on the rail 201 .

[0043] 12 , in the braking mechanism 7 configured as described above, when the rear carrier 100B approaches the front carrier 100A and the buffer protrusions 5 enter the receiving surface 60 of the buffer receiving portion 6, the tips of the buffer protrusions 5 come into contact with the second flat surface portion 70b of the brake link 70, causing the brake link 70 to rotate downward as shown by arrow T. When the brake link 70 rotates, the slider 72 attached to the brake link 70 comes into contact with the rail base 201a, generating sliding friction and braking the carriers 100A and 100B.

[0044] As described above, the conveying device 200A according to the third embodiment has the braking mechanism 7, which can reduce the collision speed of the carrier 100 and thereby alleviate the impact force. Furthermore, the impact force can be reduced, which allows the buffer mechanism 4 to be made smaller. Furthermore, the load acting on the rollers 2 supporting the carrier body 1 and the rolling bearings (not shown) can be reduced, which can extend the mechanical life of the carrier 100. Note that the braking link 70 is not limited to a configuration in which it is rotatably supported by the pin 71 as shown, but may be rotatably supported by a leaf spring structure or other structure.

[0045] 13 is a side view showing the pressing force and the contact reaction force vector of the braking mechanism of the conveyance device according to the third embodiment. As shown in FIG. 13, the contact reaction force of the buffer protrusion 5 against the braking link 70 is expressed as a contact reaction force vector F ｒ , contact reaction force vector F ｒ The angle between the vertical direction (Z direction) and the rear carrier 100B is defined as a pressing force vector F ｘ When expressed as a pressing force vector F ｘ and the contact reaction force vector F ｒ The relationship is expressed by equation (6).

[0046]

[0047] When the coefficient of friction between the buffer protrusion 5 and the receiving surface 60 of the buffer receiving portion 6 is μ and equation (7) is satisfied, the wedge effect causes the buffer protrusion 5 to be fixed to the receiving surface 60 of the buffer receiving portion 6 without slipping.

[0048]

[0049] That is, the wedge slope exerts a pressing force vector F ｘ is amplified by 1 / sinθ times to produce the contact reaction force vector F ｒ Then, this contact reaction force vector F ｒ is the inclined surface pressing force, and a sliding friction reaction force is generated by multiplying it by the friction coefficient μ. ｘ The larger the frictional reaction force, the greater the sliding frictional reaction force, causing so-called automatic tightening, which causes the buffer protrusion 5 to adhere to the receiving surface 60 of the buffer receiving portion 6. This stuck state can be easily released by controlling the thrust of the front and rear carriers 100A, 100B to generate thrust in the direction that moves the carriers 100A, 100B away from each other. Then, by smoothly starting the carriers 100A, 100B from the state in which automatic tightening has been released, it becomes possible to transition to the normal transport mode.

[0050] On the other hand, when the buffer protrusion 5 is fixed to the receiving surface 60 of the buffer receiving portion 6 and the rear carrier 100B is further pressed against the front carrier 100A, the pressing force is accumulated as elastic deformation of the buffer protrusion 5 and the buffer receiving portion 6, and even if the drive control of the carriers 100A and 100B is turned off, the restoring force due to the elastic deformation and the frictional force are balanced, so that the carriers 100A and 100B are held stationary.

[0051] Each carrier 100A, 100B is equipped with a mover core 30, and the thrust of each carrier 100A, 100B is controlled independently of the other carriers 100A, 100B by controlling the current of a stator coil (not shown). Therefore, the pressing force required to hold the carriers 100A, 100B stationary can be adjusted, and by setting the frictional force greater than the weight of the carriers 100A, 100B, it is possible to prevent displacement due to the carrier's own weight. In other words, even if the rail 201 is disposed in a vertical plane and the weight of the carriers 100A, 100B includes a vertical component, the carriers 100A, 100B can be held stationary by turning off the drive control of the carriers 100A, 100B.

[0052] 14 is a top view schematically illustrating a state in which the conveying device according to the third embodiment is caused to travel along a curved rail 202. As shown in FIG. 14, the conveying device 200A according to the third embodiment can achieve the above-described effects even when it is caused to travel along a curved rail 202, similar to when it is caused to travel along a straight rail 201.

[0053] The configurations shown in the above embodiments are merely examples, and may be combined with other known technologies or may be combined with other embodiments. Furthermore, it is also possible to omit or change part of the configurations without departing from the spirit of the invention.

[0054] REFERENCE SIGNS LIST 1 Carrier main body, 2 Roller, 3 Movable element, 4 Buffer mechanism, 5 Buffer protrusion, 6 Buffer receiving portion, 7 Braking mechanism, 10 First surface portion, 11 Second surface portion, 12 Third surface portion, 30 Movable element core, 60 Receiving surface portion, 70 Braking link, 70a First flat portion, 70b Second flat portion, 71 Pin, 72 Slider, 100, 100A, 100B Carrier, 200, 200A Conveying device, 201, 202, 203 Rail, 201a Rail base, 300 Conveyed object.

Claims

1. A conveying device comprising a plurality of carriers that are independently driven and controlled by linear motors and travel on the same rail to transport objects, wherein the carriers comprise: a carrier main body that holds the objects and travels along the rail; and a buffer mechanism that is attached to the carrier main body and reduces the impact force when adjacent carriers collide with each other, wherein the buffer mechanism has a buffer protrusion that protrudes toward the carrier located in front, and a buffer receiving part that receives the buffer protrusion of the carrier traveling behind, and the buffer receiving part has a receiving surface that is recessed toward the inside of the carrier main body and is concave and fits over the buffer protrusion of the carrier traveling behind.

2. The conveying device according to claim 1, wherein the receiving surface portion has a side wall surface that is curved from the opening end of the concave shape toward the bottom of the groove.

3. A conveying device as described in claim 1 or 2, characterized in that the transported object is held on the upper part of the carrier main body, and the buffer receiving part is installed on the upper surface of the carrier main body near the center of gravity of the entire structure including the transported object and the carrier.

4. A conveying device as described in claim 1 or 2, characterized in that the transported object is held on the vertical side of the carrier main body, and the buffer receiving parts are installed at the top and bottom of the carrier main body, centered on the overall center of gravity including the transported object and the carrier.

5. A conveying device according to any one of claims 1 to 4, characterized in that the carrier further comprises a braking mechanism that brakes the carrier by sliding friction with the rail.

6. The conveying device according to claim 5, characterized in that the braking mechanism comprises a braking link that rotates when the buffer protrusion abuts against it, and a slider that moves in conjunction with the rotation of the braking link and comes into contact with a part of the rail to generate sliding friction.

7. A conveying device according to claim 6, characterized in that, when the angle between the contact reaction force vector of the buffer protrusion with respect to the brake link and the vertical direction is θ and the coefficient of friction between the buffer protrusion and the buffer receiving portion is μ, θ is set so that μ > tan θ.

Images