Uniaxial actuator

Abstract

To provide a uniaxial actuator which can be miniaturized while suppressing costs.SOLUTION: A non-excitation brake 4 which regulates rotation of a motor shaft 2a and ball screw shaft 3b is provided between a drive motor 2 and a ball screw mechanism 3. The non-excitation brake 4 comprises a brake plate 4e having a coupling fitting hole 4f at an inner diameter part between a movable magnetic plate 4c and a fixed brake plate 4d. A coupling 5 inserts a motor shaft coupling hub 5a for coupling the motor shaft 2a into the coupling fitting hole 4f, and the motor shaft coupling hub 5a and the coupling fitting hole 4f are formed in shapes to become impossible to relatively rotate, respectively. A flange member 6 is connected with an end surface 3g of a bracket part 3c of the ball screw mechanism 3b by spigot, the flange member 6 is coupled with the drive motor 2 with a coupling bolt 7, and the non-excitation brake 4 is fixed between the flange member 6 and the drive motor 2.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a single-axis actuator used in XY tables, industrial robots, etc., and more particularly to a single-axis actuator with an integrated motor. [Background technology]

[0002] In general, a single-axis actuator includes a drive motor and a ball screw mechanism that converts the rotation of the drive motor into linear motion. The ball screw mechanism includes a ball screw shaft that rotates when the drive motor is operated and a slider that includes a ball screw nut that is screwed onto the ball screw shaft. The motor shaft of the drive motor and the ball screw shaft are connected by a coupling. In addition, single-axis actuators used in industrial equipment are required to be compact by shortening the longitudinal length of parts other than the reciprocating part of the slider. However, when connecting the drive motor and the ball screw mechanism, an intermediate flange is interposed between them, and the drive motor and the ball screw mechanism are bolted to the intermediate flange, respectively, which makes the longitudinal length of the single-axis actuator long. In addition, there has been an actuator that has been shortened in the longitudinal length by forming the ball screw shaft and the motor shaft of the drive motor integrally and omitting the coupling (see Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2003-230251 A Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the case of the above-mentioned Patent Document 1, it is difficult to integrate the ball screw shaft and the motor shaft. In particular, when the length of the ball screw shaft becomes long, there is no manufacturing equipment that can handle the motor winding process and the core press-fitting process. In order to handle this, large-scale manufacturing equipment is required, which increases costs.

[0005] SUMMARY OF THE PRESENT EMBODIMENT An object of the present invention is to provide a single-axis actuator that can be made compact while keeping costs down. [Means for solving the problem]

[0006] In order to achieve the above-mentioned object, a single-shaft actuator of the present invention comprises a drive motor and a ball screw mechanism that converts rotation of the drive motor into linear motion, the ball screw mechanism comprising a ball screw shaft that rotates by operation of the drive motor, and a slider including a ball screw nut that screws onto the ball screw shaft, and in the single-shaft actuator in which the motor shaft of the drive motor and the ball screw shaft are connected by a coupling, a non-excitation brake that regulates rotation of the motor shaft and the ball screw shaft is provided between the drive motor and the ball screw mechanism, and the non-excitation brake comprises a brake plate having a coupling fitting hole in its inner diameter portion, between a movable magnetic plate and a fixed brake plate, and the coupling is characterized in that a motor shaft connecting hub that connects the motor shaft is inserted into the coupling fitting hole, and the motor shaft connecting hub and the coupling fitting hole are each formed in a shape that prevents relative rotation.

[0007] Furthermore, it is preferable that a flange member is connected to the drive motor side end face of the ball screw mechanism, the flange member and the drive motor are connected with a connecting bolt, and the non-excited brake is fixed between the flange member and the drive motor, and the flange member has a concave-convex shape that fits into the concave-convex shape formed on the drive motor side end face. Effect of the Invention

[0008] The non-excitation brake of the single-axis actuator of the present invention restricts the rotation of the brake plate, which rotates integrally with the coupling, by pressing it against a fixed brake plate via a movable magnetic plate, thereby restricting the rotation of the motor shaft and the ball screw shaft. The present invention uses such a non-excitation brake as the brake for the drive motor, and furthermore, the brake plate and the motor shaft connecting hub of the coupling are connected in an overlapping state in the axial direction, so that it is possible to reduce the axial length of the single-axis actuator while keeping costs down.

[0009] In addition, since the flange member and the connecting bolt are used to connect the drive motor and the ball screw mechanism and the non-excitation brake can be fixed between the flange member and the drive motor, the number of parts can be reduced and the axial length of the single-axis actuator can be shortened. Furthermore, since the flange member has a concave-convex shape that fits into the concave-convex shape formed on the end face on the drive motor side, it is possible to minimize the increase in the axial length of the single-axis actuator due to the flange member. [Brief description of the drawings]

[0010] [Figure 1] 1 is a partially sectional front view of a single-axis actuator showing one embodiment of the present invention; [Diagram 2] FIG. [Diagram 3] FIG. [Figure 4] FIG. 2 is a left side view of the ball screw mechanism. [Diagram 5] FIG. [Figure 6] FIG. 2 is a cross-sectional front view of a non-excitation brake. [Figure 7] FIG. 4 is a right side view of the non-excitation brake. [Figure 8] FIG. 4 is a plan view of the flange member and the connecting bolt. [Figure 9] FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] 1 to 9 are diagrams showing an example of a single-axis actuator of the present invention. The single-axis actuator 1 includes a drive motor 2 that is a rotational drive source and can rotate in both forward and reverse directions, a ball screw mechanism 3 that converts the rotation of the drive motor 2 into linear motion, a non-excitation brake 4 disposed between the drive motor 2 and the ball screw mechanism 3, and a coupling 5, which are arranged in series in the axial direction of the ball screw mechanism 3. The actuator further includes a flange member 6 attached to the ball screw mechanism 3, and four connecting bolts 7 that connect the flange member 6 to the drive motor 2 and fix the non-excitation brake 4 between the drive motor 2 and the ball screw mechanism 3.

[0012] 1 to 4, the ball screw mechanism 3 is housed in a main body case 3a. In the main body case 3a, there are provided a guide rail (not shown) extending in the longitudinal direction of the main body case 3a, a ball screw shaft 3b arranged along the guide rail via a bearing plate (not shown), and a slider 8 having a ball screw nut (not shown) screwed onto the ball screw shaft 3b, and as the ball screw shaft 3b rotates, the slider 8 reciprocates along the ball screw shaft 3b. In addition, a bracket portion 3c is provided on the drive motor side of the ball screw mechanism 3.

[0013] The bracket portion 3c is provided with a coupling housing portion 3d that rotatably houses the coupling 5, and one end of the ball screw shaft 3b is provided to protrude into the coupling housing portion 3d. Furthermore, a recess 3e (concave-convex shape of the present invention) for spigot-connecting the flange member 6 and insertion holes 3f for four mounting bolts 9 that attach the flange member 6 to the bracket portion 3c are provided on the drive motor side surface of the bracket portion 3c (the drive motor side end surface of the ball screw mechanism).

[0014] 1, 2 and 5, the coupling 5 connects the motor shaft 2a of the drive motor 2 to the ball screw 3b, and has a rectangular motor shaft connecting hub 5a on the drive motor 2 side. The coupling 5 is provided with a motor shaft connecting hole 5b for connecting the motor shaft 2a to the motor shaft connecting hub 5a, and a ball screw shaft connecting hole 5c for connecting the ball screw shaft 3b on the ball screw mechanism 3 side. Furthermore, the motor shaft connecting hub 5a is provided with a fixing bolt insertion hole 5d, through which a fixing bolt 10 for fixing the motor shaft 2a is inserted, in a direction perpendicular to the motor shaft connecting hole 5b.

[0015] As shown in Figs. 1, 2, 6 and 7, the non-excitation brake 4 has a yoke 4a attached to the drive motor 2 side and a coil 4b. Between the yoke 4a and the bracket part 3c, a movable magnetic plate 4c is arranged on the yoke 4a side, and a fixed brake plate 4d is arranged on the bracket part 3c side, and the fixed brake plate 4d and the drive motor 2 are connected with three bolts 11. Between the movable magnetic plate 4c and the fixed brake plate 4d, a brake plate 4e is provided, and the movable magnetic plate 4c and the brake plate 4e are provided so as to be movable in the axial direction. The fixed brake plate 4d is connected with three bolts 11 via three collars 4i, and is provided so as to be movable in the axial direction but not rotatable. Between the movable magnetic plate 4c and the fixed brake plate 4d, a brake plate 4e is provided so as to be movable in the axial direction.

[0016] The brake plate 4e is provided with a rectangular coupling fitting hole 4f into which a rectangular columnar motor shaft connecting hub 5a is fitted, and by fitting the motor shaft connecting hub 5a into the coupling fitting hole 4f, the motor shaft connecting hub 5a and the coupling fitting hole 4f cannot rotate relative to each other, and the brake plate 4e and the coupling 5 rotate together. In addition, the yoke 4a and the movable magnetic plate 4c are provided with a motor shaft insertion hole 4g ​​through which the motor shaft 2a is inserted, and the fixed brake plate 4d is provided with a coupling insertion hole 4h through which the coupling 5 is inserted. Furthermore, the yoke 4a is provided with a spring (not shown) that abuts against the movable magnetic plate 4c.

[0017] When no current flows through the drive motor 2 and the coil 4b, the electromagnetic attraction force of the non-excitation brake 4 does not act on the movable magnetic plate 4c, and the movable magnetic plate 4c moves toward the fixed brake plate 4d due to the elastic force of the spring, pushing the brake plate 4e and pressing the brake plate 4e against the fixed brake plate 4d. This restricts the rotation of the brake plate 4e, and restricts the rotation of the motor shaft 2a and the ball screw shaft 3b via the coupling 5. On the other hand, when a current flows through the drive motor 2 and the coil 4b, the movable magnetic plate 4c is attracted to the coil 4b side, and the brake plate 4e is free, so that the motor shaft 2a and the ball screw shaft 3b rotate together with the brake plate 4e via the coupling 5.

[0018] As shown in Figures 1, 2, 8 and 9, the flange member 6 is a plate-shaped member attached to the drive motor side end face 3g of the bracket portion 3c (the drive motor side end face of the ball screw mechanism), and is provided on both widthwise sides with connecting bolt insertion holes 6a, through which four connecting bolts 7 are respectively inserted, and mounting bolt insertion holes 6b, through which four mounting bolts 9 are inserted.

[0019] Furthermore, a coupling insertion hole 6c through which the coupling 5 is inserted is formed in the center of the flange member 6. A convex portion 6d (the concave-convex shape of the present invention) for spigot-connecting the flange member 6 is formed on the outer periphery of the coupling insertion hole 6c in correspondence with the concave portion 3e. Also, a fixing bolt insertion hole 6e through which a fixing bolt (not shown) for fixing the coupling 5 is inserted is formed from the upper portion of the flange member 6 toward the coupling insertion hole 6c in a direction perpendicular to the coupling insertion hole 6c.

[0020] The connecting bolts 7 connect the flange member 6 and the drive motor 2, and by fastening the connecting bolts 7, the non-excitation brake 4 is fixed between the flange member 6 and the drive motor 2.

[0021] The single-axis actuator 1 described above uses the non-excitation brake 4 as a brake for restricting the rotation of the motor shaft 2a and the ball screw shaft 3b, thereby making it possible to shorten the axial length of the single-axis actuator 1. Furthermore, the brake plate 4e of the non-excitation brake 4 and the motor shaft connecting hub 5a of the coupling 5 are connected in an overlapping state in the axial direction, making it possible to further shorten the axial length of the single-axis actuator 1.

[0022] Also, since the flange member 6 and the connecting bolt 7 are used to connect the drive motor 2 and the ball screw mechanism 3, and the non-excitation brake 4 can be fixed between the flange member 6 and the drive motor 2, it is possible to reduce the number of parts and shorten the axial length of the single-axis actuator 1. Furthermore, since the bracket portion 3c and the flange member 6 are spigot-connected by the recessed portion 3e and the protruding portion 6d, the flange member 6 can minimize the increase in the axial length of the single-axis actuator 1.

[0023] The present invention is not limited to the above-described embodiment in which the motor shaft connecting hub is formed into a rectangular column shape and the coupling fitting hole of the brake plate is formed into a rectangular hole shape, as long as they are formed into a shape that prevents them from rotating relative to each other, for example, a spline shape with teeth that engage with each other is also acceptable. [Explanation of symbols]

[0024] 1... Single-axis actuator, 2... Drive motor, 2a... Motor shaft, 3... Ball screw mechanism, 3a... Main body case, 3b... Ball screw shaft, 3c... Bracket portion, 3d... Coupling housing portion, 3e... Recess, 3f... Insertion hole, 3g... End surface, 4... Non-excitation brake, 4a... Yoke, 4b... Coil, 4c... Movable magnetic plate, 4d... Fixed brake plate, 4e... Brake plate, 4f... Coupling fitting hole, 4g... Motor shaft insertion hole, 4h... Coupling insertion hole, 4i... Collar, 5... Coupling, 5a... Motor shaft connecting hub, 5b... Motor shaft connecting hole, 5c... Ball screw shaft connecting hole, 5d... Fixing bolt insertion hole, 6... Flange member, 6a... Connecting bolt insertion hole, 6b... Mounting bolt insertion hole, 6c... Coupling insertion hole, 6d... Convex portion, 6e... Fixing bolt insertion hole, 7... Connecting bolt, 8... Slider, 9... Mounting bolt, 10... Fixing bolt, 11... Bolt

Claims

1. A drive motor and a ball screw mechanism that converts the rotation of the drive motor into linear motion, the ball screw mechanism includes a ball screw shaft that rotates by operation of the drive motor, and a slider including a ball screw nut that is screwed onto the ball screw shaft; In a single-axis actuator in which a motor shaft of the drive motor and the ball screw shaft are connected by a coupling, a non-excitation brake is provided between the drive motor and the ball screw mechanism to regulate rotation of the motor shaft and the ball screw shaft; The non-excitation brake includes a brake plate between a movable magnetic plate and a fixed brake plate, the brake plate having a coupling fitting hole on an inner diameter portion thereof, The coupling is characterized in that a motor shaft connecting hub that connects the motor shaft is inserted into the coupling fitting hole, and the motor shaft connecting hub and the coupling fitting hole are each formed in a shape that prevents relative rotation.

2. a flange member is connected to an end face of the ball screw mechanism on a drive motor side, the flange member and the drive motor are connected to each other by a connecting bolt, and the non-excitation brake is fixed between the flange member and the drive motor; 2. The single-axis actuator according to claim 1, wherein the flange member has a concave-convex shape that fits into a concave-convex shape formed on the end surface of the drive motor side.

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