JP3919302B2 - Automatic tool changer - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an automatic tool changer in which an output shaft for exchanging tools slides by swinging an arm.
[0002]
[Prior art]
FIG. 7 is a cross-sectional view of a conventional automatic tool changer disclosed in Japanese Utility Model Laid-Open No. 64-001830. An input shaft 1 and an output shaft 2 connected to a drive device (not shown) are arranged in an orthogonal direction. A turret 4 is disposed on the outer peripheral surface of the output shaft 2 via a spline 3. The turret 4 is rotatably supported by a tapered roller bearing 5. As a result, the output shaft 2 is slidable with respect to the turret 4 and can rotate integrally with the turret 4. A plurality of cam followers 6 are provided on the outer peripheral surface of the turret 4. The cam follower 6 is engaged with a taper rib 8 of a roller gear cam 7 formed on the input shaft 1.
[0003]
The fulcrum portion 10 of the arm 9 is supported by the housing and is provided to be swingable. The force point portion 11 of the arm 9 is engaged with a flat groove cam 12 formed on one surface of the roller gear cam 7. As the force point portion 11 of the arm 9, a roller such as a cam follower is often used in consideration of the problem of abrasion. The arm action point 13 is engaged with an annular groove 14 formed at the end of the output shaft 2.
[0004]
The operation of the automatic tool changer will be described. When the input shaft 1 is rotated by a drive device (not shown), the plurality of cam followers 6 are sequentially energized by the taper ribs 8 of the roller gear cam 7, and the turret 4 and the output shaft 2 rotate together. Further, when the input shaft 1 rotates, the power point portion 11 of the arm 9 moves along the flat groove cam 12, and the arm 9 swings. As a result, the output shaft 2 connected at the action point 13 of the arm 9 slides in the axial direction. As described above, the tool can be changed via the output shaft 2 that rotates and slides.
[0005]
[Problems to be solved by the invention]
However, in the above-described automatic tool changer, when the output shaft 2 is overloaded, such as when the output shaft 2 is in contact with an obstacle and cannot perform a predetermined operation, or when the tool cannot be attached and detached smoothly. In addition, the drive motor (not shown) does not stop immediately, and there is a possibility that the force point 11 of the arm such as a cam follower may be damaged.
[0006]
Therefore, the present invention is for solving such a problem, and provides an automatic tool changer capable of preventing damage to a power point portion of an arm even when an overload acts on an output shaft. With the goal.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, according to the present invention, an arm that swings by rotation of the input shaft is connected to an input shaft to which a driving force is input, and the output shaft slides in the axial direction by the swing of the arm. In such an automatic tool changer, the input shaft is formed with a sliding worm having a substantially spiral groove and having a constricted portion at a substantially central portion in the axial direction, and the arm is a swing shaft. It has a fulcrum part and a force point part and an action point part that move in an arc shape around the fulcrum part when the arm swings, and this force point part engages with a substantially spiral groove of the sliding worm. And a sliding spherical member that is moved along the constricted portion along with the rotation of the input shaft and receives a swinging force from a substantially spiral groove, and the operating point of the arm is connected to the output shaft. And
[0008]
In addition, the arm has a piston having one end face that partially accommodates the spherical member for sliding, a cylinder part that contains the piston, and is disposed in the cylinder part and engages with the other end face of the piston. And an elastic member that urges the piston and the sliding spherical member toward the sliding worm.
[0009]
Further, a rotating worm having a substantially spiral groove is formed on the input shaft, and the output shaft is engaged with the outer periphery of the output shaft via a spline so that the output shaft is slidably supported in the axial direction. It disposed the rotation transmitting member rotating output shaft integrally with the outer periphery of the rotation transmitting member, integral rotation transmission member and the output shaft with the substantially rotation of spiral groove engages the input shaft of the rotating worm You may comprise so that multiple rotation spherical members which receive the rotational force to rotate may be arrange | positioned.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment in which the present invention is implemented in an automatic tool changer will be described with reference to the drawings.
FIG. 1 is a longitudinal sectional view of an automatic tool changer.
The automatic tool changer includes a main body 21, a drive motor 22, and a relay unit 23 that connects the main body 21 and the drive motor 22 with bolts. In the housing of the main body 21, an input shaft 24 to which the driving force of the drive motor 22 is input, an output shaft 25 that operates so as to change tools, and the output shaft 25 are slid in the axial direction, that is, the front-rear direction. An arm 26 to be moved is provided.
[0011]
The input shaft 24 is rotatably supported by two tapered roller bearings 27 provided in the housing, and one end of the input shaft 24 is connected to the drive shaft 28 of the drive motor 22. A rotation worm 29 for rotating the output shaft 25 and a sliding worm 30 for sliding the output shaft 25 below the rotation worm 29 are formed on the input shaft 24.
[0012]
The output shaft 25 is accommodated in a housing of the main body 21 and a cylindrical shaft cover 31 connected to the housing, and a spline 32 is partially formed on the outer peripheral surface. A turret 33 is fitted in the spline 32 portion. The output shaft 25 and the turret 33 have a relationship of transmitting rotation to each other, and at the same time, a relationship in which the output shaft 25 is slidable with respect to the turret 33.
[0013]
On the outer peripheral surface of the turret 33, recesses in which metal balls (rotating spherical members) 34 can roll and are partially accommodated are formed at equal intervals in six circumferential directions. A substantially cylindrical retainer 35 is disposed between the housing and the shaft cover 31. The metal balls 34 are also accommodated in a ring-shaped groove formed on the inner peripheral surface of the retainer 35 so as to be able to roll. Thereby, the output shaft 25 and the turret 33 are supported by the retainer 35 through the metal balls 34 so as to rotate integrally.
[0014]
As shown in FIG. 2, the input shaft 24 and the output shaft 25 are not perpendicular to each other but are in a positional relationship that intersects at a substantially right angle at a short distance. The rotating worm 29 formed on the input shaft 24 is formed at substantially the same height as the turret 33. A substantially spiral groove 36 is formed on the outer surface of the rotating worm 29. A cutout 37 is formed on a side portion of the retainer 35, and the outer peripheral portion of the rotating worm 29 partially enters the cutout 37, and the substantially spiral groove 36 is formed by the metal ball 34. Is engaged. When the input shaft 24 rotates, the substantially spiral groove 36 of the rotating worm 29 moves the metal ball 34 of the turret 33 as the rotating worm 29 rotates, and the turret 33 and the output shaft 25 are moved in FIG. The groove is rotated as shown in the timing chart.
[0015]
The metal ball 34 of the turret 33 transmits a rotational force to the turret 33 and simultaneously supports the turret 33 in a rotatable manner, and has both a role as a cam follower and a tapered roller bearing in the prior art. Therefore, the automatic tool changer can be made compact and the number of parts can be reduced.
[0016]
The arm 26 is positioned below the output shaft 25, and is supported by a tapered roller bearing 38 in a swingable manner on the left and right sides of the housing, as shown in FIG. That is, as shown in FIGS. 3 and 4, the arm 26 includes a swing shaft portion (fulcrum portion) 39 whose both ends are supported by the tapered roller bearing 38 as described above, and the swing shaft portion 39. A cylinder portion 40 formed at an end portion and extending substantially in the front-rear direction, and a lever portion (action point portion) 41 having a base portion above the central portion of the swing shaft portion 39 and the cylinder portion 40 and extending substantially upward. It is configured.
[0017]
A cam follower (action point portion) 42 is provided at the tip of the lever portion 41, and the cam follower 42 is assembled in an annular groove 43 formed at the rear end of the output shaft 25 so as to be freely rollable. . As a result, when the arm 26 swings around the swinging shaft portion 39, the cam follower 42 at the tip of the lever portion 41 moves in an arc shape, and the output shaft 25 slides in the axial direction. Since the groove 43 with which the cam follower 42 is engaged is formed in an annular shape, the rotation of the output shaft 25 is not hindered by the cam follower 42 even when the output shaft 25 rotates while sliding. .
[0018]
As shown in FIG. 4, the cylinder portion 40 is a cylindrical portion that is open at both ends. A piston 44 (power point portion) is accommodated in the cylinder portion 40. One end of the piston 44 protrudes from the opening in front of the cylinder portion 40. A plug 45 is attached to the rear opening of the cylinder portion 40. On one end face of the piston 44, a concave portion 47 is formed in which a metal ball (sliding spherical member, force point portion) 46 can roll and is partially accommodated. The sliding worm 30 is formed with a substantially spiral groove 48, and the metal ball 46 accommodated in the recess 47 of the piston 44 is also transferred to the substantially spiral groove 48 of the sliding worm 30. It is movable and partially contained. The substantially spiral groove 48 of the sliding worm 30 moves a metal ball 46 provided on the piston 44 as the input shaft 24 rotates, swings the arm 26, and causes the output shaft 25 to move in the timing chart of FIG. The groove is slid like this.
[0019]
A piston rod 49 extends from the other end surface of the piston 44, and a plurality of disc springs (elastic members) 50 are disposed around the piston rod 49. Accordingly, the piston 44 and the metal ball 46 are always urged toward the sliding worm 30 by the elastic force of the plurality of disc springs 50. A collar 51 is disposed between the plurality of disc springs 50 and the plug 45. As will be described later, this structure provides a function as a torque limiter that prevents breakage due to overload.
[0020]
The sliding worm 30 has a constricted portion 52 having an outer diameter that is not uniform in the vertical direction, and a substantially central portion in the vertical direction having the smallest outer diameter. The shape of the constricted portion 52 is a shape that does not hinder the swing of the arm 26, and in the longitudinal section of the sliding worm 30 shown in FIG. 4, the arc-shaped locus of the end face of the piston 44 when the arm 26 swings. It has a shape corresponding to. When the input shaft 24 rotates, the metal ball 46 accommodated in the concave portion 47 of the piston 44 is guided upward or downward along the constricted portion 52 by the substantially spiral groove 48 of the sliding worm 30. The entire arm 26 is swung by receiving a swing force F in a substantially tangential direction of the constricted portion 52 from the metal ball 46. At this time, since the metal ball 46 of the piston 44 is spherical, stress concentration is difficult to occur, and the metal ball 46 has sufficient strength, and is unlikely to be damaged like a conventional cam follower. Further, since the metal balls are small in size as compared with the cam follower, the strength is sufficient, so that the automatic tool changer can be made compact accordingly.
[0021]
Next, the operation of the automatic tool changer configured as described above will be described. As shown in the conceptual diagram of FIG. 6, an arm 55 that holds a tool 53 to be collected at one end and a tool 54 to be newly attached to the other end is attached to the tip of the output shaft 25. And
[0022]
First, when the rotational angle position of the input shaft 24 is 0 degrees to less than 13 degrees, the arm 26 does not swing and the output shaft 25 does not slide.
When the rotational angle position of the input shaft 24 is less than 13 degrees to less than 45 degrees, the lever portion 41 of the arm 26 swings backward, and the output shaft 25 moves backward as shown in FIGS. Then, the tool 53 to be collected is pulled out from the mounting portion 56.
When the rotational angle position of the input shaft 24 is 45 degrees to less than 83 degrees, as shown in FIGS. 6B to 6C, the output shaft 25 moves backward while rotating.
When the rotational angle position of the input shaft 24 is 83 degrees to less than 252 degrees, the output shaft 25 rotates but does not slide. The output shaft 25 rotates 180 degrees between (b) and (d) in FIG. Thereby, the tool 54 which should be newly attached has moved to the position which opposes the attachment part 56 to a tool. Further, when the rotation angle position of the input shaft 24 is 252 degrees to less than 278 degrees, the output shaft 25 does not rotate or slide.
If the rotational angle position of the input shaft 24 is less than 278 degrees to less than 347 degrees, the lever portion 41 of the arm 26 swings forward, and the output shaft 25 moves forward as shown in FIGS. Then, a tool 54 to be newly attached is set on the attachment portion 56.
[0023]
As described above, the tools are exchanged. During this time, when an overload is applied during the operation of the output shaft 25, the torque limiter including the piston 44 and the plurality of disc springs 50 provided on the arm 26 operates. . That is, the piston 44 of the cylinder portion 40 of the arm 26 can move toward the inside of the cylinder portion 40 by compressing the plurality of disc springs 50 when a force exceeding the elastic force of the plurality of disc springs 50 is applied. Thus, when the output shaft 25 is overloaded, the metal ball 46 moves toward the inside of the cylinder portion 40 together with the piston 44 and comes out of the substantially spiral groove of the sliding worm 30. For this reason, in this embodiment, an overload does not act on the component between the output shaft 25 and the drive motor until the drive motor is stopped as in the prior art, and the breakage of the component is prevented.
[0024]
【The invention's effect】
As described above, according to the automatic tool changer of the first aspect, the force point portion of the arm engages with the substantially spiral groove of the sliding worm but is a spherical member. It is hard to break even under load.
According to the automatic tool changer of the second aspect, when the output shaft is overloaded, the sliding spherical member comes off the substantially spiral groove of the sliding worm. In addition, it is possible to prevent breakage of parts between the output shaft and the drive motor.
According to the automatic tool changer according to claim 3, since the rotating spherical member has both the role of transmitting the rotational force to the turret and the role of rotatably supporting the turret, the automatic tool changer Can be made compact, and the number of parts can be reduced.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view relating to an automatic tool changer according to an embodiment of the present invention.
2 is a top cross-sectional view mainly showing an internal structure of a housing of the automatic tool changer of FIG. 1. FIG.
3 is a front sectional view mainly showing an internal structure of a housing of the automatic tool changer of FIG. 1;
4 is a partially enlarged view showing a peripheral portion of an arm of the automatic tool changer of FIG. 1. FIG.
FIG. 5 is a timing chart for explaining the operation of the output shaft.
FIGS. 6A and 6B are explanatory views conceptually showing a process of exchanging tools, wherein (a), (b), (c), (d), and (e) are rotation angles of the input shaft, respectively. It is a figure which shows a tool exchange state when a position is 13 degrees, 45 degrees, 83 degrees, 252 degrees, and 347 degrees.
FIG. 7 is a cross-sectional view of a conventional automatic tool changer.
[Explanation of symbols]
24 Input shaft 25 Output shaft 26 Arm 29 Rotating worm 30 Sliding worm 32 Spline 33 Turret 34 Metal ball 39 Oscillating shaft portion 40 Cylinder portion 41 Lever portion 42 Cam follower 44 Piston 46 Metal ball 47 Recess 50 Disc spring 52 Constriction Department.

Claims (3)

In an automatic tool changer in which an arm that swings by the rotation of the input shaft is connected to the input shaft to which the driving force is input, and the output shaft slides in the axial direction by the swing of the arm.
The input shaft is formed with a sliding worm having a substantially spiral groove and having a constricted portion at a substantially central portion in the axial direction,
The arm has a fulcrum portion that is a swing shaft, and a force point portion and an action point portion that move in an arc shape around the fulcrum portion when the arm swings,
The force point portion engages with the substantially spiral groove of the sliding worm, moves along the constricted portion as the input shaft rotates, and receives a swinging force from the substantially spiral groove. Contains
The automatic tool changer characterized in that the action point of the arm is connected to the output shaft. The arm is
A piston having at one end surface a recess that partially accommodates the sliding spherical member;
A cylinder portion for accommodating the piston;
And an elastic member disposed in the cylinder portion and engaged with the other end surface of the piston to urge the piston and the spherical member for sliding toward the sliding worm. The automatic tool changer according to claim 1. The input shaft is formed with a rotating worm having a substantially spiral groove,
On the outer periphery of the output shaft, a rotation transmission member that is engaged through a spline and slidably supports the output shaft in the axial direction and rotates integrally with the output shaft is disposed.
On the outer periphery of the rotation transmitting member , there is a rotating spherical member that engages with a substantially spiral groove of the rotating worm and receives a rotational force that integrally rotates the rotation transmitting member and the output shaft as the input shaft rotates. The automatic tool changer according to claim 1 or 2, wherein a plurality of automatic tool changers are arranged.

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