Vacuum generation device

Abstract

A vacuum generation device (1A) comprises: one or more vacuum pumps (3); check valves (23), the number of which is the same as that of the vacuum pumps (3); and fall prevention valves (24), the number of which corresponds to the number of suction pads (5) that each sucks an object by drawing in a fluid through a drawing-in port (3H) by driving of the corresponding vacuum pump (3). The fall prevention valves (24) each comprise: a valve element (241) having a first through-hole (241H) through which a fluid drawn in from the corresponding suction pad (5) is allowed to flow toward the corresponding vacuum pump (3) side; and a valve seat (242) having a second through-hole (242H) formed at a position away from the first through-hole (241H).

Description

Vacuum Generator

[0001] The present invention relates to a vacuum generating device.

[0002] There is known a suction device (vacuum generating device) that includes one vacuum pump, a plurality of suction pads each connected to the vacuum pump, and a valve (fall prevention valve) provided on each of the suction pads to prevent fluid from flowing from the suction pad toward the vacuum pump (see, for example, Patent Document 1).

[0003] The valve of this adsorption device included a housing, a spherical valve element housed inside the housing, a first valve seat disposed on one side of the valve element, and a second valve seat disposed on the other side of the valve element.

[0004] Japanese Patent Application Laid-Open No. 2021-88016

[0005] However, the technology described in Patent Document 1 leaves room for improvement in terms of the size of the vacuum generating device.

[0006] The present invention has been made in view of the above, and an object of the present invention is to provide a small-sized vacuum generating device.

[0007] To solve the above problems and achieve the object, the vacuum generating device of the present invention comprises one or more vacuum pumps, the same number of check valves as the vacuum pumps, and fall prevention valves corresponding to the number of suction pads that suck fluid through suction ports when driven by the vacuum pump to suck in an object. The fall prevention valves comprise a valve body having a first through hole that allows fluid sucked from the suction pads to pass toward the vacuum pump, and a valve seat having a second through hole formed in a position offset from the first through hole.

[0008] According to one aspect of the present invention, a small vacuum generating device can be provided.

[0009] FIG. 1 is a perspective view of a vacuum suction device (vacuum generating device) according to an embodiment. FIG. 2 is a cross-sectional view taken along the line A-A in FIG. 1 . FIG. 3 is a cross-sectional view of a portion of FIG. 2 . FIG. 4 is a perspective view of a suction pad, an attachment, and a branching member included in the vacuum suction device shown in FIG. 1 . FIG. 5 is an exploded view of the suction pad, the attachment, the branching member, the check valve, and the fall prevention valve included in the vacuum suction device shown in FIG. 1 . FIG. 6 is a partially cutaway perspective view of the suction pad, the attachment, the branching member, the check valve, and the fall prevention valve included in the vacuum suction device shown in FIG. 4 . FIG. 7 is a cross-sectional view showing a state in which the suction path is blocked by a check valve included in the vacuum generating device shown in FIG. 1 . FIG. 8 is a cross-sectional view showing a state in which the suction path is open by a check valve included in the vacuum generating device shown in FIG. 1 . FIG. 9 is an exploded perspective view of the fall prevention valve included in the vacuum generating device shown in FIG. 1 . FIG. 10 is a cross-sectional view showing a state in which the suction path is open by the fall prevention valve shown in FIG. 9 . Fig. 11 is a cross-sectional view showing a state in which the suction path is blocked by the fall prevention valve shown in Fig. 9. Fig. 12 is a piping diagram showing an outline of the initial state of the vacuum suction device shown in Fig. 1. Fig. 13 is a piping diagram showing an outline of a state in which the vacuum suction device has been moved downward from the initial state shown in Fig. 12 and the suction pads have been pressed against the target object. Fig. 14 is a piping diagram showing an outline of a state in which the vacuum suction device has been moved downward from the initial state shown in Fig. 12 and the suction pads have been pressed against the target object, with one suction pad incompletely suctioning.

[0010] A vacuum generating device according to an embodiment will be described below with reference to the drawings. However, the present invention is not limited to this embodiment. Furthermore, the dimensional relationships and ratios of elements in the drawings may differ from the actual situation. The dimensional relationships and ratios may differ between the drawings. Furthermore, the content described in one embodiment is, in principle, applicable to other embodiments as well.

[0011] [Embodiment] A vacuum suction device 1 having a vacuum generating device 1A according to this embodiment is mounted on a manipulator such as a robot, and is used in a device that grips and transports an object 6 by driving a vacuum pump 3 to suction the object 6. The vacuum suction device 1 is mounted on, for example, a so-called six-axis articulated robot that can move the vacuum suction device 1 in a first direction, a second direction, and a third direction. In other words, the vacuum suction device 1 according to this embodiment can move in the first direction, the second direction, and the third direction by driving the six-axis articulated robot. Such a six-axis articulated robot is installed, for example, on a product assembly line or manufacturing line. The vacuum suction device 1 may also be mounted on industrial robots such as horizontal articulated robots, parallel link robots, Cartesian robots, and collaborative robots.

[0012] FIG. 1 is a perspective view of a vacuum suction device 1 (vacuum generator 1A) according to an embodiment. FIG. 2 is a cross-sectional view taken along the line A-A in FIG. 1 . In describing the vacuum suction device 1 (vacuum generator 1A) according to an embodiment, to facilitate understanding of directions, the axial direction of the fall prevention valve 24 is referred to as the first direction (Z-axis direction), the direction in which a plurality of suction pads 5 (three in this embodiment) are arranged and included in a plane perpendicular to the first direction is referred to as the second direction (X-axis direction), and the direction included in a plane perpendicular to the first direction and perpendicular to the second direction is referred to as the third direction (Y-axis direction). The first direction, the second direction, and the third direction are mutually orthogonal. The first direction is, for example, a vertical direction, and includes an upper side, which is the first positive direction, and a lower side, which is the first negative direction. The second direction includes the second positive direction and the second negative direction. The third direction includes the third positive direction and the third negative direction. In the drawings, only the first positive direction side, the second positive direction side, and the third positive direction side are shown, and the first negative direction side, the second negative direction side, and the third negative direction side are omitted, but these negative direction sides are opposite to the positive direction side. Also, as described above, since the vacuum suction device 1 is mounted on a robot or the like, the above-mentioned directions change when the robot is driven.

[0013] 1, the vacuum generation device 1A includes, for example, a main body 2, one or more vacuum pumps 3, and a plurality of attachments 4 (see FIG. 2). A plurality of suction pads 5 are attached to the main body 2 of the vacuum generation device 1A to form the vacuum suction device 1. The vacuum suction device 1 according to this embodiment includes, for example, one main body 2, two vacuum pumps 3, three attachments 4, and three suction pads 5.

[0014] The main body 2 includes, for example, a case 2a and a cover 2b, and is formed of a resin material in a generally rectangular parallelepiped shape. A connection part 21 for attaching to a robot is provided in the center of the case 2a. Two vacuum pumps 3, for example, are attached to the main body 2. More specifically, the plurality of vacuum pumps 3 are attached to the first forward side of the main body 2.

[0015] Next, we will explain the vacuum pump 3. The vacuum generation device 1A according to this embodiment includes two vacuum pumps 3, but since the two vacuum pumps 3 have the same configuration, we will explain one of the two vacuum pumps 3 below and omit the explanation for the remaining vacuum pump 3.

[0016] The vacuum pump 3 according to this embodiment is a cartridge type that is detachably attached to the main body 2. As shown in Fig. 2, the vacuum pump 3 includes a cylindrical pump body 31 that is closed at the top and forms an internal space, a bottom plate 32 that closes the internal space at the bottom of the pump body 31, and a connecting member 33 provided on the bottom plate 32.

[0017] The connecting member 33 is disposed at the center of the bottom plate 32 when viewed from the first negative side, and has a suction port 3H. The vacuum pump 3 sucks fluid into the interior of the vacuum pump 3 through the suction port 3H. The vacuum pump 3 also includes a filter (not shown) disposed at the connection port 5H1. When the vacuum pump 3 is driven, it sucks fluid (e.g., air) through the suction port 3H, generating a vacuum in the suction path 2R formed inside the main body 2.

[0018] Such a vacuum pump 3 starts and stops operating in response to commands from the control unit of the external device. When a drive command is sent from the control unit of the external device, the vacuum pump 3 starts operating and sucks the fluid in the suction path 2R through the suction port 3H into the vacuum pump 3. On the other hand, when a stop command is sent from the control unit of the external device, the vacuum pump 3 stops operating and stops sucking the fluid in the suction path 2R through the suction port 3H into the vacuum pump 3.

[0019] The attachment 4 connects the main body 2 and the suction pad 5. The attachment 4 is attached to the first negative direction side of the main body 2. The attachment 4 according to this embodiment is detachable from the branching member 22 provided on the main body 2.

[0020] Next, a description will be given of the suction pads 5. The vacuum suction device 1 according to this embodiment includes three suction pads 5, but since the three suction pads 5 have the same configuration, only one of the three suction pads 5 will be described below, and a description of the remaining suction pads 5 will be omitted.

[0021] Each suction pad 5 has, for example, a pad body 51 and a contact portion 52 provided on the pad body 51, and is integrally formed from synthetic rubber or the like. As shown in FIG. 3 , a connection port 5H1 is provided at the end of the pad body 51 on the first positive side. The contact portion 52 is a portion that contacts the object 6 and is formed to be elastically deformable. The contact portion 52 is formed in a continuous ring shape when viewed from the first negative side. Furthermore, a suction port 5H2 is formed on the first negative side of the contact portion 52. Inside the suction pad 5, the connection port 5H1 and the suction port 5H2 are connected to each other. The suction pad 5 having such a configuration is connected to the main body 2 via the attachment 4.

[0022] Next, the main body 2 will be described again with reference to Figures 2 and 3. Figure 3 is a cross-sectional view of a portion of Figure 2. Inside the main body 2, a branching member 22, a check valve 23, a fall prevention valve 24, multiple pipes 25, a solenoid valve (not shown), and a pressure sensor (not shown) are arranged. The branching member 22, the check valve 23, the fall prevention valve 24, and the multiple pipes 25 form a suction path 2R inside the main body 2. Inside the main body 2, the suction path 2R also connects the connection port 5H1 and the suction port 3H.

[0023] The suction path 2R according to this embodiment includes, for example, a first suction path 2R1, a second suction path 2R2, and a third suction path 2R3. The first suction path 2R1 extends linearly along the first direction and connects the suction port 3H of the vacuum pump 3 to the connection port 5H1 of the suction pad 5. In other words, the first suction path 2R1 is formed along an axis 2R1o extending along the first direction. The vacuum generation device 1A according to this embodiment includes, for example, two first suction paths 2R1. When the vacuum generation device 1A is used to suction the target part 6, the vacuum pump 3 is driven to suck the fluid in the suction path 2R through the suction port 3H of the vacuum pump 3. At this time, the fluid flows through the first suction path 2R1 from the first negative direction to the first positive direction.

[0024] The second suction path 2R2 branches off from the first suction path 2R1 midway and extends linearly along the second direction to connect the two first suction paths 2R1. The third suction path 2R3 branches off from the second suction path 2R2 midway and extends linearly along the first direction.

[0025] The suction pad 5 is disposed on the first negative direction side of the third suction path 2R3 via a connecting member. That is, the third suction path 2R3 connects the suction pad 5 disposed at the center in the second direction to the second suction path 2R2.

[0026] When the vacuum pump 3 is driven with the suction pad 5 in contact with the object 6, the suction path 2R is brought into a low-pressure state (hereinafter referred to as "vacuum") where the pressure is reduced by a predetermined value below atmospheric pressure. That is, in this embodiment, "vacuum" refers to a state where the pressure is lower than atmospheric pressure by a predetermined value.

[0027] A vacuum pump 3 is disposed on the first positive side of the first suction path 2R1, while a suction pad 5 is disposed on the first negative side of the first suction path 2R1 via an attachment 4. Therefore, for the sake of convenience, in the suction path 2R of the vacuum generating device 1A according to this embodiment, the vacuum pump 3 side is referred to as the upstream side, and the suction pad 5 side is referred to as the downstream side.

[0028] Next, the branching member 22 will be described with reference to Figures 3, 4, 5, and 6. Figure 4 is a perspective view of the suction pad 5, attachment 4, and branching member 22 provided in the vacuum suction device 1 shown in Figure 1. Figure 5 is an exploded view of the suction pad 5, attachment 4, branching member 22, check valve 23, and fall prevention valve 24 provided in the vacuum suction device 1 shown in Figure 1. Figure 6 is a perspective view with parts cut away of the suction pad 5, attachment 4, branching member 22, check valve 23, and fall prevention valve 24 provided in the vacuum suction device 1 shown in Figure 4.

[0029] 5, the branching member 22 includes a first portion 221 extending in the first direction, a second portion 222 extending from the center of the first portion 221 toward the second negative direction in the first direction, and a third portion 223 extending from the center of the first portion 221 toward the third negative direction in the first direction. The first portion 221 forms a part of the first suction path 2R1.

[0030] The second portion 222 forms part of the second suction path 2R2 and is a portion branching off from the first suction path 2R1 to the second suction path 2R2. The third portion 223 is a portion branching off from the first suction path 2R1, and the end of the third suction path 2R3 is connected to other components described below.

[0031] In first portion 221 of branching member 22, the first forward direction side portion formed in a cylindrical shape accommodates check valve 23 and fall prevention valve 24.

[0032] The cylindrical portion of first portion 221 of branching member 22 on the first negative direction side accommodates filter 222a and first O-ring 222b. That is, branching member 22 includes filter 222a and first O-ring 222b.

[0033] Next, the check valve 23 will be described with reference to Figures 3, 5, 6, 7, and 8. Figure 7 is a cross-sectional view showing a state in which the suction path 2R is blocked by the check valve 23 provided in the vacuum generating device 1A shown in Figure 1. Figure 8 is a cross-sectional view showing a state in which the suction path 2R is open by the check valve 23 provided in the vacuum generating device 1A shown in Figure 1.

[0034] The check valve 23 is provided midway along the first suction path 2R1 and prevents backflow of the fluid from the suction pad 5 toward the vacuum pump 3. The check valve 23 includes a first valve seat 231, a first valve body 232, a biasing member 233, and a second O-ring 234. The first valve seat 231 includes, for example, a cylindrical case 231a and a cylindrical cover 231b that covers the case 231a, and has a first housing space 23s that can house a valve body main body 232a of the first valve body 232. In the radial direction of the check valve 23, the end of the first portion 221 of the branching member 22 on the first positive direction side is sandwiched between the case 231a and the cover 231b.

[0035] The case 231a is formed with a through hole 23H that connects the first positive side and the first negative side of the first suction passage 2R1 (see FIGS. 3 and 6).

[0036] The first valve body 232 includes a valve body main body 232a formed in a disk shape, and a rod member 232b, a portion of which is located in the first accommodating space 23s and a portion of which protrudes outward from the first accommodating space 23s.

[0037] The biasing member 233 constantly biases the first valve body 232 toward the first negative direction against the first valve seat 231. The biasing member 233 is, for example, a coil spring.

[0038] The second O-ring 234 is disposed in a space formed by the case 231 a , the cover 231 b , and the first portion 221 of the branching member 22 .

[0039] The check valve 23 having such a configuration is formed so as to extend along its axis, and is disposed so that the axis of the check valve 23 coincides with the axis 2R1o of the first suction passage 2R1.

[0040] In the check valve 23 according to this embodiment, the entire first valve body 232 is provided so as to be movable relative to the first valve seat 231 in the direction in which the fluid flows (i.e., the first direction).

[0041] As shown in Figure 7, when the first valve body 232 is urged toward the first negative direction by the urging force of the urging member 233, for example, when the vacuum pump 3 is stopped, the first valve body 232 is positioned on the first negative direction side, and the through hole 23H is blocked by the valve body main body 232a, thereby blocking communication between the first negative direction side and the first positive direction side of the first suction path 2R1.

[0042] 8, when first valve body 232 is positioned on the first positive side, the first negative side and the first positive side of first suction path 2R1 are connected to each other through through hole 23H. For example, when vacuum pump 3 is driven to suck fluid from first suction path 2R1, the flow of fluid moves first valve body 232 to the first positive side against the biasing force of biasing member 233, and the first negative side and the first positive side of first suction path 2R1 are connected to each other through through hole 23H.

[0043] That is, the check valve 23 prevents the fluid from flowing from the first positive direction side to the first negative direction side in the first suction path 2R1. That is, the check valve 23 prevents the fluid from flowing backward from the suction pad 5 toward the vacuum pump 3.

[0044] Next, the fall prevention valve 24 will be described with reference to Figures 3, 5, 6, 9, 10, and 11. Figure 9 is an exploded perspective view of the fall prevention valve 24 provided in the vacuum generating device 1A shown in Figure 1. Figure 10 is a cross-sectional view showing a state in which the suction path 2R is communicated by the fall prevention valve 24 shown in Figure 9. Figure 11 is a cross-sectional view showing a state in which the suction path 2R is blocked by the fall prevention valve 24 shown in Figure 9.

[0045] The fall prevention valve 24 is provided midway along the first suction path 2R1, and prevents fluid from flowing from the suction pad 5 toward the vacuum pump 3. The fall prevention valve 24 includes a second valve seat 242, a second valve body 241, and a stopper 243, and is formed to extend along its axis, with the axis of the fall prevention valve 24 being positioned so that it coincides with the axis 2R1o of the first suction path 2R1.

[0046] Second valve body 241 has, for example, a cylindrical portion 241a formed in a cylindrical shape, and a plate-like portion 241b closing the first positive direction side of cylindrical portion 241a.

[0047] A first through-hole 241H that communicates the first positive side and the first negative side of the first suction path 2R1 is formed in the plate-shaped portion 241b of the second valve body 241. The first through-hole 241H allows the fluid flowing in from the suction pad 5 to pass to the vacuum pump 3 side. The first through-hole 241H is disposed in the center including the axis of the fall prevention valve 24. The first through-hole 241H is formed in a plane of the second valve body 241 that intersects (orthogonal in this embodiment) with the direction in which the fluid flows (from the first negative side to the first positive side in the first direction).

[0048] The second valve seat 242 has a first cylindrical portion 242a formed in a cylindrical shape, and a second cylindrical portion 242b that is smaller than the first cylindrical portion 242a and is positioned on the first positive direction side of the first cylindrical portion 242a.

[0049] The second valve seat 242 also has a second through-hole 242H formed between the first cylindrical portion 242a and the second cylindrical portion 242b. The second through-hole 242H connects the first positive side and the first negative side of the first suction path 2R1 in the fall prevention valve 24. The second through-hole 242H allows the fluid flowing in from the suction pad 5 to pass through to the vacuum pump 3. The second through-hole 242H is disposed radially outward with respect to the axis of the fall prevention valve 24. The second through-hole 242H is formed in a plane in the second valve seat 242 that intersects (orthogonal in this embodiment) with the direction in which the fluid flows (from the first negative side to the first positive side in the first direction).

[0050] Additionally, the first cylindrical portion 242a of the second valve seat 242 has a second accommodation space 24s capable of accommodating the second valve body 241. In the fall prevention valve 24 according to this embodiment, the entire second valve body 241 is accommodated in the second accommodation space 24s of the second valve seat 242. The second valve body 241 is formed of a metal material or a resin material having a predetermined rigidity. In other words, the second valve body 241 according to this embodiment does not undergo elastic deformation.

[0051] As described above, the first through hole 241H is disposed at the center including the axial center of the fall prevention valve 24, and the second through hole 242H is disposed radially outward with respect to the axial center of the fall prevention valve 24. Therefore, the second through hole 242H is formed at a position offset from the first through hole 241H. In other words, when viewed from the axial direction of the fall prevention valve 24, the first through hole 241H and the second through hole 242H do not overlap. More specifically, when the fall prevention valve 24 is viewed from the first negative direction side, the second cylindrical portion 242b of the second valve seat 242 is visible through the first through hole 241H, but the second through hole 242H is not visible. In addition, when the fall prevention valve 24 is viewed from the first positive direction side, the second cylindrical portion 241b of the second valve body 241 is visible through the second through hole 242H, but the first through hole 241H is not visible.

[0052] The stopper 243 has an annular stopper body 243a and protrusions 243b that protrude radially inward from the inner circumferential surface of the stopper body 243a. The stopper 243 according to this embodiment has one stopper body 243a and four protrusions 243b. The four protrusions 243b are arranged to face each other in the radial direction.

[0053] In stopper 243, the length in the radial direction between two protruding portions 243b is shorter than the length in the radial direction of the outer peripheral surface of cylindrical portion 241a of second valve body 241. Therefore, when assembling fall prevention valve 24, after second valve body 241 is placed in second accommodation space 24s of second valve seat 242, stopper 243 is placed inside first portion 221 of branching member 22 from the first negative direction side, and then second valve body 241 and second valve seat 242 are inserted into first portion 221 of branching member 22 from the first negative direction side, stopper 243 can prevent second valve body 241 from falling off second valve seat 242.

[0054] In addition, in the second accommodation space 24s of the fall prevention valve 24 according to this embodiment, the entire second valve body 241 is provided so as to be movable along the direction in which the fluid flows (i.e., the first direction) relative to the second valve seat 242. In the vacuum generating device 1A according to this embodiment, the direction in which the second valve body 241 moves relative to the second valve seat 242 is the axial direction of the fall prevention valve 24.

[0055] When the flow rate of fluid in the first suction path 2R1 per unit time is less than a predetermined flow rate, the second valve body 241 is positioned on the first negative side, as shown in Figure 10, thereby connecting the first negative side and the first positive side of the first suction path 2R1 through the first through hole 241H and the second through hole 242H.

[0056] On the other hand, when the flow rate of the fluid in the first suction path 2R1 per unit time exceeds a predetermined flow rate, as shown in Figure 11, the flow of fluid causes the second valve body 241 to be positioned on the first positive direction side, so that the second through hole 242H is blocked by the second valve body 241 (more specifically, the plate-shaped portion 241b of the second valve body 241), and the first through hole 241H is blocked by the second valve seat 242 (more specifically, the second cylindrical portion 242b of the second valve seat 242), thereby blocking communication between the first negative direction side and the first positive direction side of the first suction path 2R1.

[0057] In the vacuum generating device 1A according to this embodiment, the above-mentioned vacuum pump 3, branching member 22, check valve 23, and fall prevention valve 24 are arranged symmetrically with respect to an imaginary line positioned at the center in the second direction.

[0058] A pressure sensor (not shown) is provided as another component via a pipe in the third portion 223 of one of the two branching members 22. The pressure sensor measures the pressure in the suction path 2R.

[0059] Furthermore, a solenoid valve (not shown) is provided as another component in the third section 223 of the other of the two branching members 22, with a pipe interposed therebetween. The solenoid valve is disposed at the end of the suction path 2R and opens and closes in response to an open command from the control unit of the external device. More specifically, when an open command is sent from the control unit of the external device, the solenoid valve opens to the outside, allowing external fluid to enter the suction path 2R (i.e., the suction path 2R is open to the atmosphere). On the other hand, when the open command is no longer sent from the control unit of the external device, the solenoid valve closes to the outside, preventing external fluid from entering the suction path 2R.

[0060] In the vacuum suction device 1 according to this embodiment, the electromagnetic valve is normally in a closed state.

[0061] On the other hand, in the vacuum suction device 1 according to this embodiment, when the vacuum pump 3 is driven and all of the suction pads 5 are adsorbing the object 6, and the transport of the object 6 is completed or the change in the position of the object 6 is completed, an open command is sent from the control unit of the external device to the solenoid valve, and fluid flows from the outside into the suction path 2R, thereby immediately releasing the object 6 from the adsorption state of the suction pads 5.

[0062] Next, the operation of the vacuum suction device 1 according to this embodiment will be described with reference to Figures 12, 13, and 14. Figure 12 is a piping diagram showing an outline of the initial state of the vacuum suction device 1 shown in Figure 1. Figure 13 is a piping diagram showing an outline of a state in which the vacuum suction device 1 has been moved downward from the initial state shown in Figure 12 and the suction pads 5 have been pressed against the target object 6. Figure 14 is a piping diagram showing an outline of a state in which the vacuum suction device 1 has been moved downward from the initial state shown in Figure 12 and the suction pads 5 have been pressed against the target object 6, with one suction pad 5 incompletely suctioned.

[0063] As shown in FIG. 12, the control unit of the external device places the target object 6 (for example, a cardboard box) below the vacuum suction device 1 in the vertical direction using a conveying device (not shown).

[0064] 13, the control unit of the external device drives the robot to move the vacuum suction device 1 downward and press all (three in this embodiment) suction pads 5 against the target object 6. In this state, as shown in FIG. 10, for example, the entire periphery of the contact portion 52 of the suction pad 5 comes into contact with the target object 6, so that the downstream end of the suction path 2R is blocked by the target object 6.

[0065] Next, the control unit of the external device sends a drive command to all (two in this embodiment) of the vacuum pumps 3. Then, each of the vacuum pumps 3 to which the drive command has been sent is driven, and the fluid in the suction path 2R is sucked through the suction port 3H, thereby creating a vacuum in the suction path 2R, and all of the suction pads 5 suction the object 6. While the object 6 is being suctioned, the flow rate per unit time does not exceed a predetermined flow rate, so in the fall prevention valve 24, the second valve body 241 is positioned on the first negative direction side, and the first suction path 2R1 is in a connected state.

[0066] Next, the control unit of the external device drives the robot to transport the target object 6 together with the vacuum suction device 1 and change the posture of the target object 6 .

[0067] Next, the control unit of the external device sends a stop command to all (two in this embodiment) vacuum pumps 3. Then, each of the vacuum pumps 3 to which the stop command has been sent stops driving and stops sucking the fluid in the suction path 2R through the suction port 3H.

[0068] The control unit of the external device also sends a stop command and an open command to the solenoid valve. The solenoid valve, upon receiving the open command, opens and allows fluid to flow from the outside into the suction path 2R, thereby releasing suction of the object 6. Finally, the control unit of the external device stops the open command to the solenoid valve at an appropriate timing, and ends the process of transporting the object 6 or the process of changing the position of the object 6.

[0069] In such a process of transporting the object 6 or a process of changing the orientation of the object 6, if the transport device does not properly transport the object 6, as shown in Fig. 14, two of the three suction pads 5 may properly contact the object 6, but the remaining suction pad 5 (hereinafter referred to as the suction pad 5 performing incomplete suction) may not properly contact the object 6. In the suction pad 5 performing incomplete suction, as shown in Fig. 11, for example, part of the contact portion 52 of the suction pad 5 is not in contact with the object 6, and the downstream end of the suction path 2R is not blocked by the object 6 and is open to the atmosphere.

[0070] In such a case, if all the vacuum pumps 3 continue to be driven, the fluid will be sucked into the vacuum pump 3 through the suction port 5H2 of the suction pad 5 that is performing incomplete suction, via the suction path 2R. In this case, because the fluid is sucked into the suction path 2R from the suction port 5H2 of one suction pad 5, the flow rate per unit time of the fluid sucked through the suction port 5H2 of the suction pad 5 that is performing incomplete suction increases compared to the flow rate per unit time sucked from the suction pad 5 when the pumps are operating normally.

[0071] In this case, the flow rate of the fluid in the first suction path 2R1 per unit time exceeds the predetermined flow rate, and the second valve body 241 moves toward the first positive direction due to the flow of the fluid, thereby blocking the first through-hole 241H and the second through-hole 242H and blocking communication between the first negative direction side and the first positive direction side of the first suction path 2R1, as shown in Fig. 11. This allows the vacuum state in the suction path 2R to be maintained, allowing the suction pad 5 to maintain the suction state of the object 6 and preventing the object 6 from falling.

[0072] The control unit of the external device then performs the same processing as in normal times, thereby enabling the object 6 to be transported appropriately.

[0073] As described above, the vacuum generator 1A according to this embodiment includes one or more vacuum pumps 3, the same number of check valves 23 as the vacuum pumps 3, and fall prevention valves 24 corresponding to the number of suction pads 5 that suck fluid from suction ports 3H when driven by the vacuum pumps 3 to adsorb an object, and the fall prevention valves 24 include a second valve body (valve body) 241 having a first through hole 241H through which the fluid sucked from the suction pads 5 can pass to the vacuum pump 3 side, and a second valve seat (valve seat) 242 having a second through hole 242H formed in a position offset from the first through hole 241H. The conventional vacuum generator of Patent Document 1 includes a spherical valve body, a housing that can accommodate the spherical valve body, and a space in the housing where the spherical valve body can move and through which the fluid can pass, which could result in the vacuum generator being large in size. On the other hand, the vacuum generating device 1A of this embodiment has a simple configuration in which the second valve body (valve body) 241 blocks the second through hole 242H of the second valve seat (valve seat) 242, and the second valve seat (valve seat) 242 blocks the first through hole 241H of the second valve body (valve body) 241, thereby blocking the suction of the vacuum pump 3 and preventing the object 6 from falling, and therefore a small-sized vacuum generating device 1A can be provided.

[0074] Furthermore, in the vacuum generating device 1A according to this embodiment, the first through hole 241H is formed on a surface that intersects with the direction in which the fluid flows in the second valve body (valve body) 241, and the second through hole 242H is formed on a surface that intersects with the direction in which the fluid flows in the second valve seat (valve seat) 242, and when viewed from the axial direction of the fall prevention valve 24, the first through hole 241H and the second through hole 242H do not overlap.

[0075] Furthermore, in the vacuum generating device 1A according to this embodiment, the fall prevention valve 24 is arranged so that the entire second valve body (valve body) 241 can move relative to the second valve seat (valve seat) 242 along the direction in which the fluid flows.

[0076] Furthermore, in the vacuum generating device 1A according to this embodiment, when the vacuum pump 3 is driven to suck fluid from the suction pad 5, the fall prevention valve 24 allows the fluid to flow in through the second through-hole 242H at the second valve seat (valve seat) 242, and allows the fluid to flow in through the first through-hole 241H at the second valve body (valve body) 241; when the flow rate exceeds a predetermined flow rate, the second valve body 241 comes into contact with the second valve seat 242, thereby blocking the first through-hole 241H with the second valve seat 242, and the second through-hole 242H with the second valve body 241, thereby preventing the flow of fluid from the suction pad 5 toward the vacuum pump 3.

[0077] Furthermore, in the vacuum generating device 1A according to this embodiment, the number of fall prevention valves 24 is equal to or less than the number of suction pads 5 .

[0078] Furthermore, in the vacuum generating device 1A of this embodiment, when a plurality of suction pads 5 suction the object 6, if some of the suction pads 5 incompletely suction the object 6, the fall prevention valve 24 of the suction pad 5 that performs the incomplete suction prevents the object 6 from falling by preventing the flow of fluid from the suction pad 5 toward the vacuum pump 3.

[0079] Furthermore, in the vacuum generator 1A according to this embodiment, the suction pads 5 are arranged at predetermined intervals, and at least the suction pads 5 located at the edges of the plurality of suction pads 5 arranged at predetermined intervals are provided with a vacuum pump 3 and a fall prevention valve 24. The vacuum generator 1A according to this embodiment is used, for example, when transporting an object 6 (e.g., cardboard) whose length in the first direction is longer than its length in the second direction. When using the vacuum generator 1A for such an object 6, the suction pads 5 located at both ends in the first direction (i.e., the suction pads 5 located at the edges) of the three suction pads 5 tend to produce an incomplete suction state. Therefore, the suction pad 5 located at the center in the first direction does not have a corresponding fall prevention valve 24, thereby providing an inexpensive vacuum generator 1A. As in the above embodiment, the fall prevention valve 24 is preferably provided at least on the suction pads 5 that suction near the edges of the object 6, and need not be provided on the suction pads 5 that suction near the edges of the object 6, where the suction pads 5 are unlikely to come off (e.g., the center of the object 6). In other words, in the vacuum generator 1A according to this embodiment, fall prevention valves 24 are provided corresponding to the suction pads 5 arranged on the edges, and fall prevention valves 24 are not provided for the suction pads 5 arranged in the center. In other words, in the vacuum generator 1A according to this embodiment, fall prevention valves 24 are provided according to the number of suction pads 5. However, fall prevention valves 24 may be provided for all of the suction pads 5.

[0080] Furthermore, in the vacuum generating device 1A according to this embodiment, the second valve body 241 of the fall prevention valve 24 is formed of a metal material or resin material having a predetermined rigidity, and the second valve body 241 does not undergo elastic deformation. On the other hand, some conventional fall prevention valves 24 have valve bodies that are formed to be elastically deformable. With such conventional fall prevention valves 24, there is a risk that they will lose proper elastic deformation and will not be able to open and close properly after long-term use. On the other hand, in the fall prevention valve 24 according to this embodiment, the second valve body 241 is formed of a metal material or resin material having a predetermined rigidity, and therefore, proper opening and closing operations can be maintained even after long-term use.

[0081] The vacuum generator 1A according to the present embodiment has been described as including two vacuum pumps 3, two check valves 23, two fall prevention valves 24, and three suction pads 5. However, the vacuum generator 1A according to the present embodiment is not limited to this, and the number of vacuum pumps 3, check valves 23, fall prevention valves 24, and suction pads 5 can be increased or decreased as appropriate depending on the object 6. For example, four vacuum pumps 3 may be provided, the main body 2 may be formed into a rectangular shape when viewed from the first direction, and the vacuum pumps 3 may be arranged at the four corners of the rectangular main body 2. The vacuum pumps 3, check valves 23, fall prevention valves 24, and suction pads 5 may be arranged according to the shape, size, etc. of the main body 2.

[0082] Furthermore, the vacuum suction device 1 according to this embodiment has been described using cardboard boxes as an example of the object 6 to be suctioned. However, the vacuum suction device 1 according to this embodiment is not limited to this, and other items (for example, bags) can also be used as the object.

[0083] Furthermore, in the above-described vacuum suction device 1 (vacuum generator 1A), when an open command is sent from the control unit of the external device, the solenoid valve opens to the outside, allowing the external fluid to enter the suction path 2R, whereas when the open command is no longer sent from the control unit of the external device, the solenoid valve closes to the outside, preventing the external fluid from entering the suction path 2R. However, the vacuum suction device 1 (vacuum generator 1A) according to the present embodiment is not limited to this. For example, the vacuum suction device 1 (vacuum generator 1A) may be configured such that when a close command is sent from the control unit of the external device, the solenoid valve closes to the outside, preventing the external fluid from entering the suction path 2R, whereas when the close command is no longer sent from the control unit of the external device, the solenoid valve opens to the outside, allowing the external fluid to enter the suction path 2R (i.e., the suction path 2R is open to the atmosphere).

[0084] The above has been a description based on an embodiment of the vacuum generating device 1A according to the present invention, but it goes without saying that the present invention is not limited to the embodiment, and various modifications are possible without departing from the spirit of the present invention. Such modifications without departing from the spirit of the present invention are also included in the technical scope of the present invention, and this will be clear to those skilled in the art from the description of the claims.

[0085] 1A Vacuum generating device, 23 Check valve, 24 Fall prevention valve, 241 Second valve body (valve body), 241H First through hole, 242 Second valve seat (valve seat), 242H Second through hole, 3 Vacuum pump, 3H Suction port, 5 Suction pad, 6 Object

Claims

1. A vacuum generating device comprising: one or more vacuum pumps; check valves in the same number as the vacuum pumps; and fall prevention valves corresponding to the number of suction pads that suck in fluid from suction ports when driven by the vacuum pumps to adsorb objects, wherein the fall prevention valves comprise: a valve body having a first through hole that allows fluid sucked from the suction pads to pass through to the vacuum pump side; and a valve seat having a second through hole formed in a position away from the first through hole.

2. A vacuum generating device as described in claim 1, wherein the first through hole is formed in a plane of the valve body that intersects with the direction of fluid flow, and the second through hole is formed in a plane of the valve seat that intersects with the direction of fluid flow, and when viewed from the axial direction of the fall prevention valve, the first through hole and the second through hole do not overlap.

3. The vacuum generating device according to claim 1 or 2, wherein the fall prevention valve is provided so that the entire valve body is movable relative to the valve seat in the direction in which the fluid flows.

4. The vacuum generating device according to claim 1 or 2, wherein the fall prevention valve, when the vacuum pump is driven to suck fluid from the suction pad, allows fluid to flow in through the second through-hole at the valve seat and through the first through-hole at the valve body, and when a predetermined flow rate is exceeded, the valve body comes into contact with the valve seat to close the first through-hole with the valve seat and closes the second through-hole with the valve body, thereby preventing the flow of fluid from the suction pad toward the vacuum pump.

5. The vacuum generating device according to claim 1 or 2, wherein the number of the fall prevention valves is equal to or less than the number of the suction pads.

6. A vacuum generating device as described in claim 5, wherein when the vacuum pump is driven to adsorb an object with a plurality of suction pads and some of the suction pads are not completely adsorbed, the fall prevention valve of the suction pad that is performing the incomplete adsorption prevents the object from falling by preventing the flow of the fluid from the suction pad toward the vacuum pump.

7. A vacuum generating device as described in claim 6, wherein a plurality of vacuum pumps are provided, the plurality of suction pads are arranged at predetermined intervals, and the vacuum pump and the fall prevention valve are provided for at least the suction pads arranged on the edges of the plurality of suction pads arranged at the predetermined intervals.

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