JP2009058069A - Motor-driven cylinder and rod tilt adjusting method of motor-driven cylinder - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a motor-driven cylinder capable of protruding a rod to the direction perpendicular to a flange surface of a mounting flange. <P>SOLUTION: A nut 3 converting rotational movement to linear movement is threadedly engaged to a screw spindle 2 rotatingly driven by a motor 1. A rod 8 is joined to the nut 3. An outer cylinder 4 covers the rod 8 and the screw spindle 2 to make the rod 8 retractable. A spline nut 10 guiding linear movement of the rod 8 is arranged in one end of the outer cylinder 4 in the axial direction. The spline nut is attached to an end surface of the outer cylinder 4 in the axial direction by a fastening member 13. The position of the spline nut 10 in the radial direction with respect to the outer cylinder 4 can be adjusted by utilizing a clearance provided in the periphery of the bolt 13. Thus, the rod 8 can be protruded to the direction perpendicular to a flange surface of a mounting flange 12. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an electric cylinder that rotationally drives a screw shaft to linearly move a nut that is screwed to the screw shaft, and causes a rod coupled to the nut to protrude and retract from an outer cylinder.

  A screw shaft of a ball screw is directly connected to a motor of a conventional electric cylinder. A nut that converts the rotational motion of the screw shaft into a linear motion is screwed onto the screw shaft. A hollow rod is coupled to the nut. When the motor rotates the screw shaft, the nut moves linearly along the screw shaft, and the rod coupled to the nut appears and disappears from the outer cylinder.

A spline nut that guides the linear motion of the rod is attached to the end of the outer cylinder in the axial direction. An attachment flange for attaching the outer cylinder to the counterpart component is provided at the end of the outer cylinder in the axial direction. If the flange surface of the mounting flange is perpendicular to the axis of the outer cylinder and the outer cylinder and the rod are coaxial, the rod protrudes in a direction perpendicular to the flange surface.
Japanese Patent No. 2938795

  In the conventional electric cylinder, the spline nut is directly press-fitted into the axial end of the outer cylinder whose inner diameter is cut, or the spline nut covered with the holder is inserted into the axial end of the outer cylinder. The spline nut was attached to the end of the outer cylinder by press-fitting into the outer cylinder.

  However, since the position of the spline nut with respect to the outer cylinder is fixed, if the machining accuracy of each part is poor, tolerances may accumulate and the rod may not be able to protrude perpendicular to the flange surface. . In particular, when the outer cylinder is elongated, it becomes difficult to process the outer cylinder straight, and it is difficult to protrude the rod in a direction orthogonal to the flange surface.

  When the rod protrudes obliquely, a large error occurs at the tip of the rod, even if there is a slight error at the position of the spline nut. Moreover, when the rod protrudes obliquely, a load is applied to the bearing that guides the rotational movement of the spline nut and the screw shaft.

  Then, an object of this invention is to provide the electric cylinder which can protrude a rod in the orthogonal direction with respect to the flange surface of a mounting flange, and the rod inclination adjustment method of an electric cylinder.

  The present invention will be described below.

  In order to solve the above-mentioned problem, the invention according to claim 1 is a screw shaft, a drive source for rotationally driving the screw shaft, and screwed to the screw shaft to convert the rotational motion of the screw shaft into linear motion. A nut coupled to the nut, an outer cylinder that covers the rod and the screw shaft so that the rod can be projected and retracted, and one end of the outer cylinder in an axial direction. An electric cylinder comprising a linear bearing for guiding linear motion and a linear bearing position adjusting mechanism capable of adjusting a radial position of the linear bearing with respect to the outer cylinder.

  According to a second aspect of the present invention, in the electric cylinder according to the first aspect, the electric cylinder is further provided at the other end in the axial direction of the outer cylinder, and rotates to guide the rotational movement of the screw shaft. A rotary bearing position adjusting mechanism capable of adjusting a radial position of the rotary bearing with respect to the outer cylinder is provided.

  According to a third aspect of the present invention, in the electric cylinder according to the first or second aspect, the linear bearing position adjusting mechanism includes a fastening member for attaching a flange of the linear bearing to an end face in the axial direction of the outer cylinder. Using the clearance between the periphery of the fastening member and the fastening member insertion hole of the flange of the linear bearing, and the clearance between the linear bearing and the outer cylinder with respect to the outer cylinder. The linear bearing can be finely moved in the radial direction.

  According to a fourth aspect of the present invention, in the electric cylinder according to the third aspect, the electric cylinder further includes a receiving port into which a protrusion of the linear bearing is fitted, and the outer cylinder is attached to a counterpart part. An attachment flange is provided, and the fastening member attaches the integrated attachment flange and the linear bearing to the end surface of the outer cylinder in the axial direction.

  According to a fifth aspect of the present invention, in the electric cylinder according to the second aspect, the rotary bearing position adjusting mechanism includes a rotary bearing holder in which the rotary bearing is accommodated, and the rotary bearing holder in the axial direction of the outer cylinder. A fastening member for attaching to the end surface of the rotary bearing holder, and using the clearance between the periphery of the fastening member and the fastening member insertion hole of the rotary bearing holder, the rotary bearing holder with respect to the outer cylinder. It can be finely moved in the radial direction.

  According to a sixth aspect of the present invention, a linear bearing for guiding the linear movement of the rod is provided at one end in the axial direction of the outer cylinder, and a screw shaft is provided at the other end in the axial direction of the outer cylinder. A method for adjusting the tilt of an electric cylinder provided with a rotary bearing for guiding rotation, and causing the rod coupled to a nut screwed to the screw shaft to protrude and retract from the outer cylinder by rotating the screw shaft. A first position adjusting step for adjusting a radial position of the linear bearing with respect to the outer cylinder, and a second position adjusting step for adjusting a radial position of the rotary bearing with respect to the outer cylinder. This is a rod tilt adjustment method for an electric cylinder.

  According to the first aspect of the present invention, since the radial position of the linear bearing provided at one end of the outer cylinder in the axial direction can be adjusted, the rod protrudes in a direction orthogonal to the flange surface of the mounting flange. be able to.

  According to the invention described in claim 2, since the radial position of the linear bearing and the rotary bearing provided at both ends in the axial direction of the outer cylinder can be adjusted, the inclination of the rod at the both ends of the outer cylinder like a seesaw. Can be adjusted. Therefore, the rod can be protruded in a direction orthogonal to the flange surface.

  According to the invention of claim 3, by loosening the fastening member, the radial position of the linear bearing with respect to the outer cylinder can be adjusted, while by tightening the fastening member, the axial direction of the flange of the linear bearing and the outer cylinder A frictional force can be generated between the end face and the linear bearing can be fixed to the outer cylinder.

  According to the fourth aspect of the invention, since the mounting flange and the linear bearing can be integrated, the rod can be projected in a direction orthogonal to the flange surface of the mounting flange.

  According to the fifth aspect of the invention, the radial position of the rotary bearing holder in which the rotary bearing is accommodated can be adjusted by loosening the fastening member, while the rotary bearing holder and the outer cylinder can be adjusted by tightening the fastening member. A frictional force can be generated between the end surface in the axial direction and the rotary bearing holder can be fixed to the outer cylinder.

  According to the invention described in claim 6, since the radial position of the linear bearing and the rotary bearing provided at both ends in the axial direction of the outer cylinder can be adjusted, the inclination of the rod at the both ends of the outer cylinder as in a seesaw. Can be adjusted. Therefore, the rod can be protruded in a direction orthogonal to the flange surface.

  FIG. 1 is a sectional view of an electric cylinder according to a first embodiment of the present invention. A screw shaft 2 of a ball screw is directly connected to an output shaft 1a of a motor 1 that is a drive source. A nut 3 that converts the rotational motion of the screw shaft 2 into linear motion is screwed onto the screw shaft 2. A circulating member 6 that circulates a ball that rolls between the ball rolling groove of the screw shaft 2 and the ball rolling groove of the nut 3 is attached to the nut 3. The rotational movement of the screw shaft 2 is guided by a rotary bearing 5 provided at the end of the outer cylinder 4 in the axial direction.

  A rod 8 that can protrude and retract from the outer cylinder 4 is coupled to the nut 3. The rod 8 is formed with a hole 8a extending in the axial direction by boring. The tip end portion of the screw shaft 2 appears and disappears in this hole 8 a of the rod 8. One end of the rod 8 is provided with a rod flange 8b and a cylindrical projection 8c. The nut 3 is integrally formed with a flange 3a having a U-shaped cross section. The protrusion 8 c of the rod 8 fits into the receiving port 3 c of the flange 3 a of the nut 3. By this fitting, the rod 8 and the nut 3 become coaxial. The rod flange 8b is coupled to the flange 3a of the nut 3 by a bolt 9 or the like. A screw 8d for attaching the rod 8 to a mating part is processed at the tip of the rod 8.

  The linear motion of the rod 8 is guided to a spline nut 10 which is a linear bearing provided at the end of the outer cylinder 4 in the axial direction. A plurality of spline grooves extending in the axial direction are processed on the outer peripheral surface of the rod 8. The spline nut 10 has a plurality of balls that can roll in the spline groove. The spline nut 10 prevents the rod 8 from rotating. Along with the linear movement of the rod 8, a plurality of balls roll between the spline grooves of the rod 8 and the spline nut 10 and circulate in the circulation path of the spline nut 10. By interposing the ball, play between the spline nut 10 and the rod 8 can be eliminated.

  The spline nut 10 is provided with a flange 10a of a linear bearing protruding from the outer peripheral cylindrical surface. The flange 10a of the linear bearing is provided with a cylindrical protrusion 10b. The protrusion 10b of the spline nut 10 is fitted into the receiving port 12a of the mounting flange 12 for mounting the outer cylinder 4 to the counterpart component. The spline nut 10 and the mounting flange 12 are integrated by an inlay structure. The integrated spline nut 10 and the mounting flange 12 are fixed to the end surface of the outer cylinder 4 by a bolt 13 which is a fastening member. When the bolt 13 is tightened, the spline nut 10 and the mounting flange 12 are fixed to the end surface of the outer cylinder 4 by the frictional force.

  FIG. 2 shows a detailed view of the integrated spline nut 10 and mounting flange 12. The spline nut 10 is not press-fitted into the outer cylinder 4. A clearance C <b> 1 is provided between the outer peripheral surface of the spline nut 10 and the inner peripheral surface of the outer cylinder 4. A clearance C2 is also provided between the periphery of the bolt 13 and the bolt insertion hole 10c of the flange of the spline nut 10 and between the periphery of the bolt 13 and the bolt insertion hole 12b of the mounting flange 12. When the bolt 13 is loosened, the integrated spline nut 10 and mounting flange 12 can be finely moved in the radial direction of the outer cylinder 4. Using these clearances C1 and C2 as adjustment allowances, the radial position of the spline nut 10 relative to the outer cylinder 4 can be adjusted. Here, a linear bearing position adjustment mechanism capable of adjusting the radial position of the spline nut 10 with respect to the outer cylinder 4 is configured by the bolts 13 and the clearances C1 and C2 which are fastening members.

  FIG. 3 shows a rotary bearing holder 16 in which the rotary bearing 5 is accommodated. In the rotary bearing holder 16 having a U-shaped cross section, for example, three rows of ball bearings which are the rotary bearings 5 are placed. The rotary bearing 5 is pushed into the rotary bearing holder 16 by the holding lid 17. The motor 1 is coupled to the presser lid 17. The holding lid 17 and the rotary bearing holder 16 are provided with foolish holes 16a and 17a through which bolts 18 as fastening members pass. A clearance C <b> 3 is provided between the periphery of the bolt 18 and the ridiculous holes 16 a and 17 a of the rotary bearing holder 16 and the pressing lid 17. When the bolt 18 is loosened, the rotary bearing holder 16 can be finely moved in the radial direction with the clearance C3 as an adjustment allowance. When the bolt 18 is tightened, the rotary bearing holder 16 can be fixed to the end surface of the outer cylinder 4 by a frictional force. Here, a rotary bearing position adjusting mechanism capable of adjusting a radial position of the rotary bearing 5 with respect to the outer cylinder 4 is configured by the bolt 18 and the clearance C3 which are fastening members.

  In FIG. 4, the outer cylinder 4 and the bolts 13 and 18 fastened to both end surfaces in the axial direction of the outer cylinder 4 are shown in black. When the bolt 13 on the spline nut 10 side of the outer cylinder 4 is loosened, the radial position of the spline nut 10 with respect to the outer cylinder 4 can be adjusted. Further, when the bolt 18 on the rotary bearing side of the outer cylinder 4 is loosened, the radial position of the rotary bearing 5 with respect to the outer cylinder 4 can be adjusted. Therefore, the protruding angle of the rod 8 can be changed. Further, if the spline nut 10 and the rotary bearing 5 are shifted in the same direction, the rod 8 can be translated. If the adjustment amount in the radial direction of the spline nut 10 and the rotary bearing 5 with respect to the outer cylinder 4 is varied, it is possible to cope with the case where the nut 3 and the rod 8 are eccentrically coupled.

  The rod tilt adjustment method for the electric cylinder will be described below. After assembling the electric cylinder so that the spline nut 10 and the rotary bearing 5 are coaxial with the outer cylinder 4, the rod 8 is actually protruded. For example, when the rod 8 is inclined downward, the bolt 13 is set in a semi-relaxed state, the mounting flange 12 is hit with a hammer or the like, and the position of the spline nut 10 is corrected upward. Then, the rod 8 is protruded. If the correction cannot be completed, the bolt 18 on the rotary bearing 5 side is set in a semi-loosened state, and the rotary bearing holder 16 is moved downward with a hammer or the like. When it is confirmed that the rod 8 protrudes in a direction orthogonal to the flange surface of the mounting flange 12, the bolts on the spline nut 10 side and the rotary bearing 5 side are closed. As described above, the inclination of the rod 8 can be adjusted.

  5 and 6 show an electric cylinder according to a second embodiment of the present invention. In the electric cylinder of this embodiment, a slide bearing is provided instead of the spline nut 10 as a linear bearing. Since the structure of the screw shaft 2, the nut 3, the rod 8, the rotary bearing 5, the rotary bearing holder 16, the holding lid 17, and the motor 1 is the same, the same reference numerals are given and the description thereof is omitted.

  As shown in FIG. 5, the slide bearing 21 is accommodated in a linear bearing holder 22 having a U-shaped cross section. On the inner peripheral surface of the slide bearing 21, a protrusion that fits into the spline groove of the rod 8 is provided. The slide bearing 21 guides the rod 8 to move linearly while preventing the rod 8 from rotating. The plain bearing 21 accommodated in the linear bearing holder 22 is closed by a pressing lid 23. A mounting flange 22 a is formed integrally with the linear bearing holder 22.

  As shown in FIG. 6, the linear bearing holder 22 is attached to the end surface of the outer cylinder 4 by a bolt 24 that is a fastening member. A clearance C4 is provided between the periphery of the bolt 24 and the bolt insertion hole 22b of the linear bearing holder 22. When the bolt 24 is loosened, the linear bearing holder 22 can be finely moved in the radial direction by utilizing the clearance. When the bolt 24 is tightened, the linear bearing holder 22 can be fixed to the outer cylinder 4 by a frictional force. Here, a linear bearing position adjusting mechanism that can adjust the radial position of the sliding bearing 24 relative to the outer cylinder 4 is configured by the bolt 24 and the clearance C4 that are fastening members.

  The present invention is not limited to being embodied in the above-described embodiment, and can be variously modified without changing the gist of the present invention. For example, when the mating part to which the rod is attached is prevented from rotating, it is not necessary to process the spline groove on the outer peripheral surface of the rod, and the outer peripheral surface of the rod may be a perfect circular cylindrical shape. Further, instead of the spline nut, a linear bearing using a roller (a linear bearing for guiding the linear motion of the rod while preventing the rotation of the rod with the roller) may be used.

Sectional drawing of the electric cylinder of 1st embodiment of this invention Detailed sectional view of spline nut and mounting flange Detailed sectional view of rotary bearing and rotary bearing holder Cross section of electric cylinder (The outer cylinder and bolts on both sides of the outer cylinder are shown in black) Sectional drawing of the electric cylinder of 2nd embodiment of this invention Detailed view of plain bearing and linear bearing holder

Explanation of symbols

1 ... Motor (drive source)
2 ... Screw shaft 3 ... Nut 4 ... Outer cylinder 5 ... Rotary bearing 8 ... Rod 10 ... Spline nut (linear bearing)
10a: Linear bearing flange 10c: Bolt insertion hole (fastening member insertion hole)
12 ... Mounting flange 12a ... Receptacle 12b ... Bolt insertion hole (fastening member insertion hole)
13, 18, 24 ... bolt (fastening member)
16 ... Rotating bearing holder 17 ... Holding lid 21 ... Slide bearing 22 ... Linear bearing holder 22b ... Bolt insertion hole (fastening member insertion hole)
C1 to C4 ... Clearance

Claims (6)

A screw shaft;
A drive source for rotationally driving the screw shaft;
A nut that is screwed onto the screw shaft and converts the rotational motion of the screw shaft into linear motion;
A rod coupled to the nut;
An outer cylinder covering the rod and the screw shaft so that the rod can be projected and retracted;
A linear bearing that is provided at one end in the axial direction of the outer cylinder and guides the linear movement of the rod;
An electric cylinder comprising: a linear bearing position adjusting mechanism capable of adjusting a radial position of the linear bearing with respect to the outer cylinder. The electric cylinder further includes
A rotary bearing that is provided at the other end in the axial direction of the outer cylinder and guides the rotational movement of the screw shaft;
The electric cylinder according to claim 1, further comprising: a rotary bearing position adjusting mechanism capable of adjusting a radial position of the rotary bearing with respect to the outer cylinder. The linear bearing position adjustment mechanism has a fastening member for attaching a flange of the linear bearing to an end surface in the axial direction of the outer cylinder,
Using the clearance between the periphery of the fastening member and the fastening member insertion hole of the flange of the linear bearing, and the clearance between the linear bearing and the outer cylinder, the linear bearing with respect to the outer cylinder The electric cylinder according to claim 1, wherein the electric cylinder can be finely moved in a radial direction. The electric cylinder further includes a receiving hole into which a protrusion of the linear bearing is fitted, and includes an attachment flange for attaching the outer cylinder to a counterpart part,
4. The electric cylinder according to claim 3, wherein the fastening member attaches the integrated mounting flange and the linear bearing to an end face in an axial direction of the outer cylinder. 5. The rotary bearing position adjusting mechanism is
A rotary bearing holder in which the rotary bearing is accommodated;
A fastening member for attaching the rotary bearing holder to the end surface in the axial direction of the outer cylinder,
The rotary bearing holder can be finely moved in the radial direction with respect to the outer cylinder using a clearance between the periphery of the fastening member and a fastening member insertion hole of the rotary bearing holder. 2. The electric cylinder according to 2. A linear bearing for guiding the linear movement of the rod is provided at one end in the axial direction of the outer cylinder, and a rotary bearing for guiding the rotation of the screw shaft at the other end in the axial direction of the outer cylinder is provided. In the method of adjusting the tilt of the electric cylinder, wherein the rod connected to a nut screwed to the screw shaft is moved in and out of the outer cylinder by rotating the screw shaft.
A first position adjusting step for adjusting a radial position of the linear bearing with respect to the outer cylinder;
And a second position adjustment step of adjusting a radial position of the rotary bearing with respect to the outer cylinder.

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