JP5106145B2 - Cylinder type actuator - Google Patents

Description

  The present invention relates to a ball screw nut that is screwed onto a ball screw shaft that is rotated by a drive mechanism, and a cylinder type actuator that facilitates fastening of a movable rod that reciprocates with the ball screw nut.

  Conventionally, as this type of cylinder type actuator, as shown in FIG. 16, a cylinder unit 104 having a ball screw shaft 102 and a ball screw nut 103 screwed into the motor unit 101 having a built-in motor 100 such as a servo motor is assembled. The ball screw shaft 102 is connected to the rotating shaft of the motor 100 via the coupling 105, and the ball screw nut 103 is reciprocated as the ball screw shaft 102 rotates. A movable rod 106 that is integrally driven is assembled to the ball screw nut 103, and the object to be conveyed is moved or the reciprocating operation is taken out by the reciprocating motion of the movable rod 106 (see Patent Document 1 and Patent Document 2). ).

According to this prior art, as shown in FIG. 17, a short hollow rod 107 is crowned and fixed on the outer peripheral side of the ball screw nut 103, and another hollow rod 108 is inserted into the hollow rod 107 so as to be movable. A rod 106 is formed and connected and fixed by a rivet 109. A front bracket 110 and a rear bracket 111 are provided in front of and behind the cylinder case 104, and two guide shaft members 112 are suspended between the front bracket 110 and the rear bracket 111. The hollow rod 107 is provided with a pin 113 in the vertical position, and the pin 113 is disposed so as to be sandwiched between the two guide shaft members 112 to restrict the rotation of the ball screw nut 103 and the movable rod 106. Yes.
Japanese Patent Laid-Open No. 08-121560 JP 2005-151758 A

  However, according to the prior art described in the above-mentioned Patent Document 2, the guide shaft member 112 is provided on the outside of the hollow rod 107, and two guide shaft members 112 are provided on each of the upper and lower sides. The size is increased and the number of parts increases, resulting in an increase in weight. Further, since another hollow rod 108 is inserted into the hollow rod 107 and connected and fixed by the rivet 109, the rivet 109 needs to be drilled, and the hole 113 for assembling the pin 113 to the hollow rod 107 is also necessary. For this reason, the cost is high and the price is high for high-precision drilling. Furthermore, since the weight of the entire actuator is increased, the output of the motor 100 as a driving source is reduced, and the axial thrust of the movable rod 106 is also lost.

  The present invention provides a cylinder-type actuator that solves the above problems, reduces the radial space, reduces the number of parts, reduces the weight, and omits high-precision drilling. Objective.

In order to solve the above problems, the present invention provides a moving body that is reciprocally operated by a drive mechanism in a cylinder case, and a fixed operating region in the cylinder case that is assembled to the moving body and integrated with the moving body. A cylinder-type actuator having a movable rod that is reciprocally operated within the movable body, a radially extending flange is provided at an end of the movable body on the drive mechanism side, and the movable rod on the drive mechanism side of the movable rod is provided. A fixture having a flange portion facing the flange is mounted on the outer peripheral surface of the base end portion , an axial mounting hole (16a) is formed in the flange provided in the movable body, and the flange of the fixture A mounting hole (18b) opposite to the mounting hole (16a) of the flange of the moving body is formed in the portion, the mounting hole (16a) formed in the flange of the moving body, and the flange portion of the fixture The formed mounting hole (18b) is fastened to each other by inserting a bolt as a fastener, and a pair of fixing elements having semi-arc-shaped arms that are combined with each other to form an annular shape are used for the fixing tool, The overlapping portions are formed at both ends of the pair of fixing elements, and the mounting holes (18b) are formed in the overlapping portions .
Further, the present invention resides in that a circumferential engagement groove for assembling the fixture is formed on the outer peripheral surface of the end of the movable rod.
Furthermore , the present invention resides in that an axial flange portion is provided at at least one non-overlapping end portion of the arm of the fixing element constituting the fixing tool.
Furthermore , the present invention lies in that a flat portion serving as a detent is formed on the inner peripheral side of the arm of the fixing element constituting the fixing tool.
In the present invention, a guide piece extending in the axial direction is extended to the outer peripheral edge of the arm of the fixing element constituting the fixing tool, and a bent portion is formed at the tip of the guide piece toward the movable rod. The anti-rotation plate is assembled to the guide piece.

According to the present invention, the following effects can be obtained.
According to the first aspect, drilling holes for fastening components is unnecessary, and the size and weight can be reduced by reducing the number of components. In addition, since a pair of fixing elements having semicircular arc-shaped arms that are combined with each other to form a ring are used for the fixing tool, drilling is not required for fastening the movable rod and the moving body, and accuracy is not required. Is economical. Furthermore, since the movable rod and the movable body are fastened by using bolts, the assembling work is easy, and precision is not required for the assembling, so that the processing is easy and economical.
According to the second aspect , since the fixing tool is assembled in the engaging groove, the fixing tool is positioned in the engaging groove, and there is no possibility that the fixing tool moves in the axial direction.
According to the third aspect , since the fixing elements are positioned with respect to each other by the flange portion in the axial direction, it is possible to prevent a problem that the fixing elements are displaced from each other.
According to the fourth aspect of the present invention , since the rotation of the fixed element is achieved by the flat portion that serves as a detent, the positioning with the moving body can be achieved.
According to the fifth aspect , the detent plate can be held by the guide piece.

Embodiments of a cylinder type actuator of the present invention will be described in detail below with reference to the drawings.
1 is a front view of a cylinder type actuator, FIG. 2 is a side view of the cylinder type actuator, FIG. 3 is a sectional view taken along line AA in FIG. 2, FIG. 4 is a sectional view taken along line BB in FIG. Fig. 6 is a cross-sectional view taken along the line C-C of Fig. 1, Fig. 6 is a cross-sectional view taken along the line D-D of Fig. 2, Fig. 7 is a cross-sectional view taken along the line EE of Fig. 2, and Fig. 8 is an exploded view of the fixture for fastening the movable rod and ball screw nut. FIG. 9 is a perspective view showing a process of assembling the fixing tool of FIG. 8, and FIGS. 10 to 15 are perspective views showing the structure of the fixing tool.

  FIGS. 1 to 7 show a cylinder type actuator. This actuator 1 has a mechanism portion 1A incorporating a movable body 2 that reciprocates, and a drive portion incorporating a drive motor 3 such as a servo motor or a stepping motor. 1B.

  The mechanism portion 1A includes a long cylinder case 4 having a hollow portion 4a having a substantially circular cross section, a ball screw shaft 5 disposed along the longitudinal direction, and a longitudinal direction ( A movable body 2 that is reciprocated is accommodated in the axial direction. The cylinder case 4 is formed by forming a substantially circular hollow portion 4a on the axis of a long casing. The cylinder case 4 has an axial direction on the inner peripheral surface of the hollow portion 4a on the diagonal line forming the corner of the casing. Guide grooves 4b are formed (see FIGS. 4 and 5).

  The movable body 2 is provided with a cylindrical ball screw nut 6 as a moving body that is engraved with an internal thread on the inner peripheral surface and is screwed onto the ball screw shaft 5, and has an inner diameter that is at least larger than the outer diameter of the ball screw nut 6. And a cylindrical movable rod 7 having an outer diameter smaller than the inner diameter of the hollow portion 4 a of the cylinder case 4. The ball screw nut 6 is inserted into the movable rod 7, and the ball screw nut 6 and the movable rod 7 are integrally fastened via a fixture 8 described later. The movable rod 7 is made of an aluminum high-precision drawing material that can be used without grinding the outer and inner periphery.

  As shown in FIG. 3, the ball screw shaft 5 has a base end 5 a on the drive motor 3 side connected to an output shaft 3 a of the drive motor 3 via a coupling 9. A base end portion 5 b is supported via a bearing 12 on an inner boss portion of a bracket 11 connecting the motor housing 10 incorporating the cylinder case 4 and the cylinder case 4. A bearing 13 that slidably supports the inner surface of the movable rod 7 is attached to the tip 5 c of the ball screw shaft 5, and is prevented from coming off via a retaining ring 14. A bearing 15 is provided on the inner peripheral surface of the tip of the cylinder case 4 and supports the movable rod 7 so as to be able to reciprocate.

Next, the structure of the fixture 8 for fastening the ball screw nut 6 and the movable rod 7 will be described with reference to FIGS.
As shown in FIG. 10, a substantially rhombus-shaped flange 16 is integrally provided on the end surface of the end portion of the ball screw nut 6 on the side of the driving motor 3, and this flange 16 is formed from the outer diameter of the ball screw nut 6. Further, an extending portion protruding outward is formed with an axial mounting hole 16a for passing a bolt 17 as a fastener described later.
On the other hand, a groove 7b having a constant width g is formed along the circumferential direction on the edge 7a of the outer peripheral surface of one side of the movable rod 7 in the same direction as the ball screw nut 6, as shown in FIG. A concave portion 7d having a constant width h and a fixed depth m is formed over a fixed length n from the end surface 7c in the axial direction on the edge 7a of the outer peripheral surface of the drive motor 3 side base end portion of the rod 7. .

Details of the fixture 8 will be described with reference to FIGS.
The fixture 8 is assembled to the groove 7b of the movable rod 7, and is composed of a pair of fixtures 18 each having a semicircular arc-shaped arm 18a extending to the left and right. A flange portion 18c having a mounting hole 18b is provided on the outer side edge of the distal end portion of the left and right arms 18a of the fixing bracket 18, and the side edge of the flange portion 18c on one side (left side in the illustrated example) is axially provided. A flange portion 18d that protrudes toward the surface is provided.
As shown in FIGS. 13 to 15, the fixing bracket 18 is formed by combining the distal ends of the arms 18 a of the fixing bracket 18 with each other to form an annular shape. In the state where the pair of fixing brackets 18 are assembled, It is formed to have a diameter that matches the peripheral surface (see FIG. 12). The fixed metal fitting 18 is assembled so that the ends of the arms 18a are overlapped so that the flange portion 18d faces upward, and the mounting hole 18b protrudes to the outside of the movable rod 7.
These fixing brackets 18 are fastened by nuts 17a by fitting the bolts 17 with the mounting holes 18b of each other. The concave portion 7d of the movable rod 7 serves as a relief when the nut 17a is attached at this time. In addition, the nut 17a can be omitted by cutting a female screw into the fixing bracket 18 with a tap.
An inner side surface of the flange portion 18c is formed as a flat portion 18e, and the flat portion 18e abuts against the concave portion 7d of the movable rod 7 to prevent the fixing tool 8 from rotating. In addition, the fixing bracket 18 is provided with a guide piece 18f having a fixed length p that extends slightly in the centrifugal direction from the outer edge of the arm 18a and is bent in the axial direction at an intermediate position between the left and right arms 18a. An engagement claw portion 18g bent toward the inner diameter side is provided at the tip of the guide piece 18f.

As shown in FIGS. 8 and 9, a detent plate 19 is assembled to the guide piece 18 f of the fixing bracket 18, and this detent plate 19 is used for suppressing the idling of the movable rod 7. The cylinder case 4 slides 4b in contact with the outer peripheral surface.
The anti-rotation plate 19 includes a plate-like plate 19a provided with a notch 19b at one end intermediate portion, and a thin portion 19c formed at the intermediate portion from the notch 19b toward the other end. . The anti-rotation plate 19 is assembled to the inside of the fixing bracket 18 so that the guide piece 18f is combined with the notch portion 19b, and the thin portion 19c is overlapped to the inside of the guide piece 18f of the fixing bracket 18 to fix the fixing plate 18. It is assembled to the metal fitting 18.

The hollow portion 4a of the cylinder case 4 is provided with a stopper mechanism for reciprocating the movable body 2 within a certain range.
A stopper 20 made of an elastic material such as rubber is attached to the inner surface boss portion of the bracket 11 at a position facing the head portion 17b of the bolt 17 in the axial direction. An elastic stopper piece 21 is provided on the rear side of the bearing 15 at a position facing the engaging claw 18g of the guide piece 18f.

Next, a procedure for assembling the cylinder type actuator will be described.
As shown in FIG. 8, a pair of fixed metal fittings 18 are arranged facing the periphery of the groove 7b of the movable rod 7, and a notch 19b is engaged with the guide piece 18f inside the guide piece 18f of the fixed metal fitting 18. In this manner, the detent plate 19 is assembled.
Then, the arms 18a of the pair of fixing brackets 18 are engaged with the grooves 7b of the movable rod 7, and the ends of the arms 18a are overlapped and assembled so that the flange 18d faces upward and the mounting holes 18b overlap. . At this time, it is assembled so that the flat portion 18 e of the arm 18 a of the fixed metal fitting 18 is positioned in the concave portion 7 d of the movable rod 7. In this way, the fixing member 8 is prevented from rotating.
On the other hand, the bolt 17 is passed through the mounting hole 16 a of the flange 16 of the ball screw nut 6, and this bolt 17 is passed through the mounting hole 18 b of the fixing bracket 18 that is overlaid, and the nut 17 a is screwed. In this way, the pair of fixed fittings 18 are assembled in the groove 7 b of the movable rod 7.
At this time, the anti-rotation plate 19 is in close contact with the inside of the guide piece 18f and is pressed against the outer peripheral surface of the movable rod 7 to suppress idling of the movable rod 7.
The movable rod 7 integrally assembled with the ball screw nut 6 is inserted into the hollow portion 4a of the cylinder case 4 with the guide piece 18f aligned with the guide groove 4b.
Thus, the ball screw shaft 5 screwed and assembled on the axis of the ball screw nut 6 is connected to the output shaft 3 a of the driving motor 3 through the coupling 9.

  Next, when the driving motor 3 is operated to drive the cylinder type actuator, the rotation of the driving motor 3 is transmitted to the ball screw shaft 5 through the coupling 9 and the ball screw shaft 5 rotates. Thus, by the rotation of the ball screw shaft 5, the ball screw nut 6 moves in the axial direction, and the movable rod 7 fastened together via the ball screw nut 6 and the fixture 8 is moved in the axial direction. The movable rod 7 is reciprocated by driving the drive motor 3 forward and reverse. At this time, stroke operation is achieved by causing the head 17b of the bolt 17 to abut against the stopper 20 and the engaging claw 18g of the guide piece 18f to abut against the stopper piece 21 so that the control unit recognizes the stop position. The reference origin can be detected. By causing the control unit to recognize the reference origin, the movable rod 7 reciprocates within a certain range.

  According to the above embodiment, since the ball screw nut 6 and the movable rod 7 are integrally fastened through the fixing tool 8, the hole machining for fastening the components can be omitted, so that the machining accuracy is not required and the cost is low. An actuator can be manufactured. Moreover, since the aluminum high-precision drawing raw material which can be used for the movable rod 7 without grinding outside outer periphery can be used, the cheap movable rod 7 can be used. In addition, since the mass of the movable rod 7 itself can be reduced, the axial thrust can be increased. Since the bearing is arranged without making the ball screw shaft end opposite to the drive source a free end, the allowable range of the movable rod 7 speed can be increased.

  The present invention is not limited to the above embodiment. In the above embodiment, the moving body is reciprocated by the ball screw mechanism including the ball screw nut 6 and the ball screw shaft 5. It can also be driven by a screw mechanism. In addition, it goes without saying that the present invention can be appropriately modified and implemented within the scope not changing the gist of the present invention.

It is a front view of a cylinder type actuator by an embodiment of the invention. It is a side view of a cylinder type actuator by an embodiment of the invention. It is the sectional view on the AA line of FIG. It is the BB sectional view taken on the line of FIG. It is CC sectional view taken on the line of FIG. It is the DD sectional view taken on the line of FIG. It is the EE sectional view taken on the line of FIG. It is a perspective view which decomposes | disassembles and shows the fixture which fastens a movable rod and a ball screw nut. It is a perspective view which shows the process of assembling the fixing metal fitting of FIG. It is a perspective view which shows the state which assembled | attached the movable rod and ball screw nut of FIG. It is a perspective view which shows the base end part of the movable rod of FIG. It is a perspective view which shows the state which assembled | attached the fixed metal fitting to the movable rod of FIG. It is a perspective view which shows the state which isolate | separated a pair of fixing metal fitting of FIG. It is a perspective view which shows the state which assembled | attached the pair of fixing metal fitting of FIG. It is a perspective view which shows the state which assembled | attached the pair of fixing metal fitting of FIG. It is a longitudinal cross-sectional view which shows the conventional cylinder type actuator. It is a perspective view which shows the conventional cylinder type actuator of FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Actuator 1A Mechanism part 1B Drive part 2 Movable body 3 Drive motor 4 Cylinder case 4a Hollow part 4b Guide groove 5 Ball screw shaft 6 Ball screw nut (moving body)
7 Movable rod 8 Fixing device 9 Coupling 10 Motor housing 11 Bracket 17 Bolt (fastener)
17a Nut (fastener)
18 fixing bracket 18a arm 18b mounting hole 18c flange 18d flange 18e flat 18f guide piece 18g engaging claw 19 anti-rotation plate

Claims (5)

A movable body that is reciprocated by a drive mechanism in a cylinder case, and a movable rod that is assembled to the movable body and is reciprocated within a certain operating region in the cylinder case integrally with the movable body. In the provided cylinder type actuator,
A flange extending in the radial direction is provided at the end of the movable body on the drive mechanism side, and a fixed portion having a flange portion facing the flange is provided on the outer peripheral surface of the base end of the movable rod on the drive mechanism side. Wear the tool,
An axial mounting hole (16a) is formed in the flange provided in the moving body, and a mounting hole (18b) facing the mounting hole (16a) of the flange of the moving body is formed in the flange portion of the fixture. Forming and attaching the mounting hole (16a) formed in the flange of the movable body and the mounting hole (18b) formed in the flange portion of the fixing tool to each other by inserting a bolt as a fastener,
A pair of fixing elements having semicircular arc-shaped arms that are combined with each other to form a ring are used as the fixing tool, and overlapping portions are formed at both ends of the pair of fixing elements, and the mounting holes ( A cylinder type actuator characterized by forming 18b) . The cylinder type actuator according to claim 1 , wherein a circumferential engagement groove for assembling the fixture is formed on the outer peripheral surface of the end of the movable rod. 3. The cylinder type actuator according to claim 1, wherein an axial flange portion is provided at least at one end portion of the arm of the fixing element constituting the fixing tool that does not overlap. The cylinder type actuator according to any one of claims 1 to 3, wherein a flat portion serving as a detent is formed on an inner peripheral side of an arm of the fixing element constituting the fixing tool. A guide piece extending in the axial direction is extended to the outer peripheral edge of the arm of the fixing element constituting the fixing tool, and a bent portion is formed at the tip of the guide piece toward the movable rod side. The cylinder type actuator according to any one of claims 1 to 4 , wherein a stop plate is assembled.

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