JP5329308B2 - Electronic component mounting head - Google Patents

Description

  The present invention relates to an electronic component mounting head, and more particularly to an electronic component mounting head that is suitable for load control when an electronic component is sucked and held by lifting and lowering a suction nozzle or mounted on a mounting target such as a wiring board. .

  In general, in an electronic component mounting head (hereinafter, also simply referred to as a mounting head), a nozzle is used when an electronic component is sucked and held from a component supply device by a suction nozzle or a held electronic component is mounted on a wiring board. Load control for pressing the electronic component downward with a predetermined load is performed by the tip portion.

  As a mounting head applied to such electronic component load control, for example, Patent Document 1 discloses the one shown in FIG.

  This conventional mounting head has a suction nozzle 112 that sucks and holds the electronic component C at the tip, a nozzle holder 113 that holds the suction nozzle 112 and constitutes the lower end portion of the nozzle shaft, and a vertical position relative to the base 111. A movable body 114 that is movably supported, a Z-axis motor 121 that constitutes a first vertical movement means 120 that drives the movable body 114 in the vertical direction, and the movable body 114 that is mounted on the movable body 114. Load compensation that cancels the weight of the suction nozzle 112 and the nozzle holder 113, and the boil coil motor (VCM) 134 constituting the second vertical movement means 130 for driving the suction nozzle 112 along the vertical direction Compression spring 116, load cell 115 for detecting the pressure applied to the tip of the suction nozzle 112, the load cell 115 and the nozzle holder side It is interposed between, and a compression spring 117 that transmits a load in the vertical direction.

  When the electronic component C sucked by the suction nozzle 112 by this mounting head is mounted on the substrate, the suction nozzle 112 attached to the lower end portion of the nozzle shaft is integrated with the moving body 114 by the Z-axis motor 121. Then, the electronic component C is pressure-mounted on the substrate by lowering the nozzle shaft by the VCM 134 after being lowered to the vicinity of the substrate.

  Further, in this mounting head, a spline shaft is adopted for the nozzle shaft on which the suction nozzle 112 is mounted at the lower end portion in order to enable vertical movement with respect to the base portion 111 and the moving body 114 and rotation of the shaft center. ing.

  As described above, the ball circulation type is used as the spline shaft for moving the suction nozzle 112 up and down by the Z-axis motor 121 and transmitting the rotation by the θ-axis motor 154 to the nozzle shaft without hindering the vertical movement. .

  However, since the ball circulation type spline shaft has a large sliding resistance when the ball circulates, resistance is generated in the lower portion 141 of the nozzle shaft due to friction and vibration, and the tip of the suction nozzle 112 is not in contact. Nevertheless, there is also a problem that the load is detected as if it were in contact.

  In order to solve such problems, a retainer-type spline shaft with a retainer that holds the ball between the nut and the shaft is adopted so that the ball is in a non-contact structure, and it can handle minute loads. A mounting head that can be used is disclosed in Patent Document 2.

JP-A-2005-32860 Japanese Patent No. 3961083

  However, in the mounting head disclosed in Patent Document 2, the retainer-type spline shaft is effective for high-accuracy mounting load control, but due to restrictions such as high processing accuracy required for itself, There is a problem that it is difficult to manufacture a spline shaft having a long stroke such as a ball circulation type, and therefore cannot be used for a mounting head that requires a long stroke operation by a Z-axis motor.

  The present invention has been made in order to solve the above-described conventional problems, and has a mounting head that can move the suction nozzle up and down with a long stroke and can realize high-precision load control when mounting electronic components. The issue is to provide.

The present invention is supported by a movable portion that is moved up and down with respect to a base portion by an operation of a vertical movement shaft, and is supported by the base portion and the movable portion so as to be capable of rotating and moving up and down, and attracted to a lower end portion. nozzles and capable nozzle shaft mounting, the pressing axis for pressing said nozzle shaft downward, and a load sensor for detecting a load applied to the nozzle axis during pressing by the pressing axis, the detection axis that supports the該荷heavy sensor In the electronic component mounting head that performs load control at the time of component mounting, the nozzle shaft includes a low resistance spline shaft that enables shaft rotation with respect to the movable portion and vertical movement with low sliding resistance. the spline shaft is disposed, and the detection axis of the load sensor facing downward, together are arranged offset relative to the nozzle axis, it is continuously formed under the pressure application shaft A load arm is connected to the nozzle shaft via a bearing, the load sensor is engaged with the load arm, and the load arm is pushed down via a load sensor pushed down by the pressure shaft, and the nozzle by axes was so that is pressed downward, it is obtained by solving the above problems.

  In the present invention, the plurality of spline shafts may have different types. At this time, the spline shafts of different types may include a ball circulation type spline shaft and a finite stroke type spline shaft which is a low resistance spline shaft. The movable part may be slidably supported by the same spline nut fixed to a rigid coupling capable of only axial rotation.

  According to the present invention, since the nozzle shaft is provided with a plurality of spline shafts including a low resistance spline shaft that enables shaft rotation with respect to the movable portion and vertical movement with low sliding resistance, By adopting a ball circulation spline shaft and a finite stroke spline shaft with low sliding resistance when mounting electronic components, it is possible to simultaneously move the nozzle up and down and load electronic components with high accuracy. can do.

A longitudinal sectional view showing an example of a conventional mounting head The perspective view which shows the whole component mounting apparatus applicable to this invention Sectional drawing which shows typically the characteristic of the mounting head of 1st Embodiment which concerns on this invention. The perspective view of the principal part section which shows typically the feature of the mounting head of a 2nd embodiment concerning the present invention.

  First, an outline of an electronic component mounting apparatus to which the mounting head according to the first embodiment of the present invention is applied will be described.

  As shown in FIG. 2, the electronic component mounting apparatus 1 normally transports electronic components that are transported by the substrate transport path 2 extending in the left-right direction and supplied to the component supply unit 3 onto the positioned substrate S. A mounting head 10 to be mounted, and an X-axis moving mechanism 12 and a Y-axis moving mechanism 14 for moving the mounting head 10 in the X direction and the Y direction, respectively, are provided.

  The X-axis moving mechanism 12 moves the mounting head 10 to which one or more suction nozzles 10 </ b> A for sucking parts can be mounted in the X-axis direction, and the Y-axis moving mechanism 14 is integrated with the X-axis moving mechanism 12. The mounting head 10 is moved in the Y-axis direction. In addition, the mounting head 10 includes a Z-axis moving mechanism that moves the suction nozzle 10A up and down in the Z-axis direction, and a θ-axis rotation mechanism that rotates the suction nozzle 10A around the nozzle axis (suction axis). I have. A substrate recognition camera 16 that captures an image of a substrate mark formed on the substrate S is attached to the mounting head 10 via a support member. In addition, a component recognition camera 18 that images a component sucked by the suction nozzle 10 </ b> A from below is disposed on the side of the component supply unit 3.

  In the electronic component mounting apparatus 1 as described above, an electronic component such as a chip is sucked and held by the suction nozzle 10A of the mounting head 10 and then mounted on a substrate S such as a printed circuit board that is positioned. ing.

  The mounting head 10 of the present embodiment is fixed to the X-axis moving mechanism 12 and moved in the X-axis direction, as schematically shown in a sectional view passing through the center of the nozzle shaft 20 in FIG. Is composed of a head plate 22 and a bracket 24 fixed thereto.

  A Z-axis motor 26 is attached to the bracket 24, and a ball screw 28A constituting the Z-axis 28 is rotatably connected to the Z-axis motor 26 via a Z-axis coupling 26A. The Z slider (movable part) 30 to which the ball screw nut 28B is fixed is movable up and down with respect to the head plate 22 through a linear guide 30A by the rotation of 28A. That is, the Z-axis moving mechanism is constituted by these elements interlocked with the Z-axis motor 26.

  A θ-axis motor 32 is attached to the bracket 24. A cylindrical θ-housing 34 is connected to the θ-axis motor 32 via a θ coupling 32A. The θ housing 34 supports a θ-axis bearing 34A. And is supported by the bracket 24 so as to be rotatable about the axis.

  Further, a ball circulation type spline nut 36 is fixed to the lower end portion of the θ housing 34, and a spline shaft 36A having a lower end portion fixed to a rigid coupling 38 is slid only in the vertical direction. It is inserted as possible. Since the spline shaft 36A is a ball circulation type, it can move up and down with a long stroke.

  The rigid coupling 38 is fixed to the Z slider 30 via a coupling bearing 38A so as to be capable of rotating only in the axial direction. A spline nut 40 is fixed.

  Further, a spline shaft 40A is inserted through the finite stroke spline nut 40. The spline shaft 40A is supported coaxially with the ball circulation type spline shaft 36A, and the spline nut 40 is provided on the outer periphery thereof. It is the same as the retainer type disclosed in Patent Document 2 and has a feature that the sliding resistance is small although it is a short stroke. That is, a θ-axis rotating mechanism is configured by these elements interlocked with the θ-axis motor 32.

  In this embodiment, the nozzle shaft 20 includes the θ housing 34, a ball circulation type spline nut 36, the spline shaft 36A, a rigid coupling 38, a finite stroke spline nut 40, and the spline shaft 40A. The bracket 24 and the Z slider 30 are supported so as to be able to rotate and move up and down, and a suction nozzle 10A can be attached to the lower end of the lower part 20A.

  A VCM (voice coil motor) 46 is fixed to the Z slider 30 and is offset from the nozzle shaft 20 via a VCM spline nut 46 A fixed to the Z slider 30 by the VCM 46 and parallel. The VCM shaft (pressurizing shaft) 48 supported on the bottom can be pressed downward, and a detection shaft 50A for supporting a load cell (load sensor) 50 at the lower end is integrally formed below the VCM shaft 48. Is formed continuously.

  On the other hand, a load arm 54 extending in the orthogonal Y direction is connected to the nozzle shaft 20 through a bearing unit (bearing) 52. This bearing unit 52 has a mechanism that allows the rotational force of the nozzle shaft 20 to escape via a built-in bearing so that the rotational force of the nozzle shaft 20 is not transmitted to the VCM shaft 48.

  The load arm 54 is connected to a lower end portion of a pressurizing spring 56A, the upper end portion of which is accommodated in the load cell case 56, and the upper end portion of the load cell 50 is fixed to the load cell 50. 56 is supported so as to be movable in the vertical direction.

  Accordingly, when the VCM 46 is driven, the load cell 50 pushes down the load arm 54 via the pressurizing spring 56A, and the suction nozzle 10A can be pressed downward, and the load at that time passes through the pressurizing spring 56A. Then, it is transmitted to the load cell 50 and detected.

  In the mounting head 10 of the present embodiment having the above-described configuration, the Z-axis 28 causes the force from the Z-axis motor 26 to be directly applied from the Z slider 30 and the linear guide 30A by the ball screw 28A constituting the Z-axis 28. Is transmitted to the slider part.

  The VCM 46, the air bearing 44 and the like attached to the Z slider 30 are integrally driven up and down by a ball screw 28A, and guided up and down by a linear guide 30A according to a rail 22A attached to the head plate 22 of the mounting head 10. Is done.

  The nozzle shaft 20 freely moves in the vertical direction by a ball circulation type spline shaft 36A constituting the nozzle shaft 20 so that the vertical movement of the Z slider 30 is not hindered, and the θ-axis motor 32 rotates in the θ direction. The suction nozzle 10A mounted on the nozzle shaft lower portion 20A connected via the intermediate θ coupling 32A and the spline coupling 42 is rotated.

  The nozzle shaft 20 is independently moved by the VCM 46 that drives the VCM shaft 48 through the retainer-type spline shaft 40A for the stroke (± 2 mm) for pressurization in addition to the movement by the ball screw 28A. It is supposed to work.

  As described above, in this embodiment, the mechanism for transmitting the θ-axis rotation that can only move in the vertical direction has two different types of spline shafts of the ball circulation type and the finite stroke (retainer type) with low friction (sliding) resistance. This is characterized in that a long stroke of the suction nozzle 10A is secured while preventing erroneous detection of the load at the nozzle tip and enabling detection of a minute load.

  In the present embodiment having the above-described configuration, the following operation is performed when detecting the load applied to the tip of the suction nozzle 10A when the mounted component is sucked or mounted.

  The vertical force received by the suction nozzle 10A is transmitted through the air bearing 44 to the bearing unit 52 and the load arm 54 extending horizontally therefrom. The load arm 54 is balanced by a pressurizing spring 56A and a self-weight canceling spring 56B, and the force from the suction nozzle 10A is transmitted to the load arm 54 and further transmitted to the load cell 50 through the pressurizing spring 56A. Thus, the load can be detected.

  Further, when a load is applied from the suction nozzle 10A to the mounted component when the component is mounted, the following operation is performed.

  When the VCM 46 pushes down the load cell 50, a force is applied to the pressurizing spring 56A. The force is transmitted to the load arm 54 and the bearing unit 52, and the mounting component can be pressurized by pushing down the suction nozzle 10 </ b> A through the air bearing 44.

  When the θ axis is rotated, the operation is as follows.

  The rotational force from the θ-axis motor 32 is transmitted to the θ housing 34 via the θ coupling 32A. The θ housing 34 is fixed to the bracket 24 by a θ axis bearing 34A so as to release rotational movement, that is, so as to be rotatable.

  Since a circulating spline nut 36 is attached to the θ housing 34, the rotational motion is transmitted to the spline shaft 36A through the circulating spline nut 36 and further to the rigid coupling 38, and is attached to the rigid coupling 38. Is transmitted to the finite stroke spline nut 40. In this case, similarly to the θ-axis bearing 34A, the rigid coupling 38 is attached to the Z slider 30 so that the rotational force is released by the coupling bearing 38A.

  The rotational motion transmitted to the finite stroke spline nut 40 is connected by the spline coupling 42 through the spline shaft 40A, and is transmitted as a rotational force to the suction nozzle 10A through the air bearing shaft (nozzle shaft lower portion) 20A. It should be noted that the load arm 54 does not prevent rotational movement by the bearing unit 52 in which a bearing (not shown) is incorporated as described above.

  Further, when the Z axis operates, the operation is as follows.

  In the Z-axis 28, the rotational force from the Z-axis motor 26 is transmitted to the ball screw 28A via the Z-axis coupling 26A. The rotational movement is converted into a linear movement by the ball screw 28 </ b> A and transmitted to the Z slider 30.

  A VCM 46, an air bearing 44, and the like are attached to the Z slider 30, and these are integrally driven by a ball screw 28A and guided up and down by a linear guide 30A according to a rail 22A attached to the head plate 22. .

  However, as described above, the nozzle shaft lower portion 20A and the VCM shaft 48 are independently operated by the VCM 46 for the stroke (± 2 mm) for pressurizing the Z slider 30 moved by the ball screw 28A. It has become. The head plate 22 is attached to the X-axis moving mechanism 12 and is moved in the XY directions so that electronic components can be sucked and mounted.

  As a spline shaft for transmitting the rotational motion of the θ-axis motor 32 during the operation of the Z-axis 28, when the Z-slider 30 is driven by the Z-axis motor 26, only the circulating spline shaft 36A moves up and down in the Z-axis direction. The finite stroke spline shaft 40A does not move.

  On the other hand, when the nozzle shaft lower portion 20A is moved up and down by the VCM 46, only the finite stroke spline shaft 40A moves up and down in the Z-axis direction, and the circulating spline shaft 36A does not operate.

  According to the embodiment described in detail above, the following effects can be obtained.

(1) Since the spline shaft for transmitting the rotational motion by the θ-axis motor 32 to the nozzle shaft 20 is used in a double (two-stage) structure, the Z-axis direction (vertical direction) by the Z-axis motor 26 Even if it operates, only the circulation type spline shaft 36A operates. Accordingly, even when the finite stroke spline shaft 40A having a short stroke is used to transmit the rotational motion by the θ-axis motor 32, the rotational motion in the θ-axis direction can be transmitted while ensuring a long stroke operation in the Z-axis direction. It became so.

(2) By having a structure in which the circulation type spline shaft 36A and the finite stroke spline shaft 40A are connected to the nozzle shaft 20 via a rigid coupling 38 whose vertical movement is restricted, and the vertical movement is separated. Even when the circulating spline shaft 36A is operated for a long stroke when the Z-axis 28 is driven, it is possible to prevent the influence of friction and vibration during the operation from being transmitted to the tip of the nozzle.

(3) By having a structure in which the circulation type spline shaft 36A and the finite stroke spline shaft 40A are connected to the nozzle shaft 20 via a rigid coupling 38 in which the vertical movement is restricted, and the vertical movement is separated. In addition to ensuring the long stroke operation by the Z-axis 28, it is possible to transmit the rotational motion by the θ-axis motor 32 to the tip of the nozzle using the finite stroke spline shaft 40A capable of sliding with low friction. Detection can be realized with high accuracy.

(4) By offsetting the positional relationship between the nozzle shaft 20 and the detection shaft 50A, which is continuously formed on the VCM shaft 48 moved up and down by the VCM 46 and connected to the load cell 50 at the lower end, the nozzle shaft 20 is Even if the load cell 50 is rotated, the load cell 50 can be prevented from rotating, so that it is possible to reliably prevent the load cell cable (not shown) from being dragged and cut as in the prior art.

  Next, a second embodiment is characterized in that an air bearing is used in place of the finite stroke spline nut 40 and the shaft 40A as a device that transmits a rotational motion in the θ-axis direction and enables a low resistance linear motion. Will be described.

  FIG. 4 is a perspective view schematically showing a cross section of the main part in the vertical direction passing through the axial center of the air bearing 60 employed in the present embodiment.

  The air bearing 60 is obtained by replacing the air spline nut 62 and the air spline shaft 62A with the finite stroke spline nut 40 and the spline shaft 40A shown in FIG. 3, respectively. The air spline nut 62 is made of a porous material such as sintered metal that is accommodated in the rigid coupling 38 and easily allows air to pass therethrough. The air spline shaft 62A is made slightly smaller than the air spline nut 62. .

  Therefore, when pressurized air is supplied from the air supply part 64 to the air spline nut 62, air pressure is generated in a slight gap between the air spline nut 62 and the shaft 62A through the porous material. Accordingly, the air spline shaft 62A is in a non-contact state with respect to the air spline nut 62, and can be moved up and down by low friction sliding. Further, since the air spline shaft 62A has a quadrangular prism shape, the portion that fits into the air spline nut 62 has a quadrangular shape (polygonal shape), so that the rotational motion in the θ-axis direction can be reliably transmitted. Note that a plurality of spline shafts, each of which is set to have different conditions such as strokes, may be installed for the same type of spline shaft.

10A ... Adsorption nozzle 20 ... Nozzle shaft 22 ... Head plate 24 ... Bracket 26 ... Z-axis motor 28 ... Z-axis 28A ... Ball screw 30 ... Z slider (movable part)
30A ... Linear guide 32 ... θ-axis motor 34 ... θ housing 36 ... Circulating spline nut 36A ... Circulating spline shaft 38 ... Rigid coupling 38A ... Coupling bearing 40 ... Finite stroke spline nut 40A ... Finite stroke spline shaft 42 ... Spline coupling 44 ... Air bearing 46 ... Voice coil motor (VCM)
48 ... VCM axis (Pressure axis)
50 ... Load cell (load sensor)
50A ... Detection shaft 52 ... Bearing unit (bearing)
54 ... Load arm 56 ... Load cell case 56A ... Pressure spring 56B ... Self-weight cancel spring 60 ... Air bearing 62 ... Air spline nut 62A ... Air spline shaft 70 ... Base

Claims (4)

A movable part that is moved up and down with respect to the base part by operation of a vertical movement axis;
A nozzle shaft that is supported by the base portion and the movable portion so as to be able to rotate and move up and down, and a suction nozzle can be attached to the lower end portion; and
A pressure shaft for pressing the nozzle shaft downward;
A load sensor for detecting a load applied to the nozzle axis during pressing by said pressing axis,
In an electronic component mounting head that includes a detection shaft that supports the load sensor and performs load control when mounting the component,
The nozzle shaft is provided with a plurality of spline shafts including a low resistance spline shaft that enables shaft rotation with respect to the movable part and low vertical movement with low sliding resistance , and
The detection shaft with the load sensor facing downward is disposed offset with respect to the nozzle shaft, and is continuously formed below the pressure shaft,
A load arm is connected to the nozzle shaft via a bearing, the load sensor is engaged with the load arm, and the load arm is pushed down via a load sensor pushed down by the pressure shaft, and the nozzle electronic component mounting head axis is characterized Rukoto is pressed downward.   The electronic component mounting head according to claim 1, wherein the plurality of spline shafts have different types.   3. The electronic component mounting head according to claim 2, wherein the spline shafts having different formats include a ball circulation type spline shaft and a finite stroke type spline shaft which is a low resistance spline shaft.   4. The electron according to claim 3, wherein the spline shaft having a finite stroke is slidably supported on the spline nut fixed to a rigid coupling that can only rotate on the movable portion. Component mounting head.

Images