JP2004136388A - Arm driving mechanism of two-joint arm mechanism - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an arm driving mechanism for largely simplifying a structure of a driving part, and easily and inexpensively satisfying high rigidity required for a constituent part of the driving part. <P>SOLUTION: In this two-joint arm mechanism, a first arm 1 and a second arm 2 parallel in the horizontal direction are pivotally attached to a bracket member 4 on root sides of both arms 1 and 2, or are arranged by being guided and held by a straight guide, a third arm 3 turning in the vertical direction is arranged on tip sides of both arms 1 and 2, and a loading part 10 of a load is arranged on the tip side of the third arm 3. For vertically rocking or lifting an arm root side support part of either of the first and second arms, a chain 17 for advancing-retreating by being wrapped around a sprocket 12 rotated by the driving force of a motor 14 is connected in an advancing-retreating part of the chain 17 on the root side of either arm 1 or 2. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to an arm driving mechanism in a load handling device using a two-joint arm mechanism.
[0002]
[Prior art]
Conventionally, a two-joint arm mechanism is formed by using a parallel link, and a driving force is transmitted to the arm of the arm mechanism to extend or retract the arm mechanism in a vertical plane, thereby raising or lowering the arm end of the arm mechanism. The load handling device that moves the load portion of the formed load forward and backward in a vertical plane, or up and down, or simultaneously performs these operations, will be described in accordance with a patent application by the inventors of the present application. Many proposals have been made without them, and many proposals have been put to practical use.
[0003]
Many of the above two-joint arm mechanisms use a pantograph mechanism using a parallelogram link. The reason for this is that when the load point of the load at the tip of the arm is moved up and down or back and forth in a vertical plane, a driving force for moving the load point is used by using an enlargement mechanism of the pantograph mechanism. This makes it possible to form a compact drive unit that transmits power.
[0004]
However, when the drive unit is configured by using the enlargement function of the pantograph mechanism by the parallel link, the fulcrum and the force point of the arm mechanism are moved to the horizontal guide and the vertical guide in order to move the load point vertically and horizontally. Since the structure must be able to transmit the driving force to at least the power point after being supported, not only does the structure of the entire drive unit become inevitably complicated, but also the fulcrum and the power point set in the arm mechanism are horizontally and vertically. Since it is movable, there is a problem of strength and a problem of so-called arm flow in which the load point moves without permission.
[0005]
In view of the above problems, the inventor of the present invention has proposed a solution disclosed in Japanese Utility Model Publication No. 5-12226. The proposed solution has a structure that can obtain the advantage that the configuration of the driving unit can be simplified.However, the simplification requires a high-output motor or the like as a driving source for raising and lowering the arm mechanism, or However, in order to obtain the positioning accuracy of the load point, a new problem arises, such as a high processing accuracy of the used part and a high rigidity at the same time.
[0006]
[Problems to be solved by the invention]
In view of the above, the present invention provides an arm drive mechanism that can greatly simplify the structure of a drive unit and that can easily and at low cost clear the high rigidity required for components of this drive unit. That is the subject.
[0007]
[Means for Solving the Problems]
In order to solve the above-mentioned problem, the configuration of the arm drive mechanism of the present invention is such that a first arm and a second arm that are parallel in the horizontal direction are pivotally attached to a bracket member at the root sides of both arms or are straight. In a two-joint arm mechanism provided with a guide held by a guide, a third arm facing the vertical direction at the distal ends of the two arms, and a load load portion provided at the distal end of the third arm, First, in order to swing up or down the supporting portion on the base side of one of the second arms, or to move up and down, the base portion of any one of the arms is wound around a sprocket rotated by a driving force of a motor or the like to advance and retreat. Are linked at the advancing and retreating portions of the chain.
[0008]
In the configuration of the present invention described above, in the two-joint arm mechanism in which the root sides of the first and second arms are pivotally attached to the bracket member, the chain moves forward or backward with respect to the pivot point of the first arm or the second arm. Connect the parts. In the two-joint arm mechanism in which the root sides of the first and second arms are slidably supported by a straight guide provided on the bracket member, a rope body is provided at the base of the arm supported by the vertical straight guide. Connect the reciprocation site.
[0009]
BEST MODE FOR CARRYING OUT THE INVENTION
Next, an embodiment of the mechanism of the present invention will be described with reference to the drawings. FIG. 1 is a side view for explaining a first example of a drive mechanism of the present invention applied to a first example and a two-joint arm mechanism, FIG. 2 is a plan view of FIG. 1, and FIG. 4 is a side view for explaining a second example of the mechanism of the present invention applied to FIG. 4, FIG. 4 is a side view for explaining a third example of the same, FIG. 5 is a plan view of a main part of the mechanism of FIGS. FIG. 6 is a side view for explaining a fourth example of the drive mechanism of the present invention applied to the two-joint arm mechanism of the second example, and FIG. 7 is a perspective view for explaining the drive mechanism of FIG.
[0010]
1 and 2, reference numerals 1 and 2 denote a first arm and a second arm which are parallel and the same length in the horizontal direction, and the distal ends of both arms 1 and 2 are pivotally connected P1 by an axis parallel to the third arm 3. , And P2, the rear ends of the arms 1 and 2 are pivotally connected to a bracket member 4 serving as a machine housing on which the mechanism of the present invention is mounted by a horizontal axis. Points P3 and P4). Here, the bracket member 4 is rotatably supported by a pole 6 or a ceiling-side support member 7 via a vertical shaft 5.
[0011]
A substantially crank-shaped fourth arm 9 is connected to the third arm via a vertical shaft bearing bracket 8, and the tip of the fourth arm 9 is formed with a grip or a gripper. The load section 10 of the applied load is formed, and thus constitutes an example of the two-joint arm mechanism aM1 to which the drive mechanism of the present invention is applied.
[0012]
As shown by the imaginary line in FIG. 1, the arm mechanism aM1 is capable of angular rotation (vertical rocking) in the vertical direction about a pivot point P3, P4 in a vertical plane, and at any turning position. Since the third arm also maintains the vertical posture, the fourth arm can be translated in the vertical direction without changing the horizontal posture. Since the arm mechanism aM1 can be pivoted about the vertical axis 5 in the horizontal plane by the bracket member 4, the load unit 10 can be positioned at an arbitrary position in the three-dimensional movable range.
[0013]
Conventionally, as the drive mechanism for moving the arm mechanism aM1 up, down, or horizontally or horizontally, particularly up and down, a drive mechanism such as Japanese Utility Model Publication No. 5-12226 has been used, and there has been a problem. As described above.
[0014]
Therefore, in the present invention, the drive mechanism of the arm mechanism aM1 is formed as follows, and will be described below. First, in the bracket member 4, a horizontal shaft 11 having a driving sprocket 12 is provided at a position located forward of the pivot points P3 and P4 and does not interfere with the base side of the first arm displaced upward. An input gear 13 provided on the outer surface of the bracket member 4 of the shaft 11 has a brake (or a brake and a clutch), and an output side of a drive source 14 such as a servomotor whose rotation is output via a speed reducer. Are combined. Specifically, an output gear 15 of a drive source 14 arranged on the outer surface of the bracket member 4 on the same surface as the gear 13 meshes with the input gear 13.
[0015]
Here, the input gear 13 and the output gear 15 of the drive source 14 are positioned on the outer surface of the bracket member 4 by replacing the two gears 13 and 15 with gears whose gear ratio is appropriately changed. This is because the boost ratio (reduction ratio) can be changed.
[0016]
The reason is, for example, that when the length of the first and second arms 1 and 2 is longer than the illustrated example, the tip speed of the arms 1 and 2 increases, and the speed is the same as when the arm length is short. This is for changing the gear ratio of the gears 13 and 15 so that
[0017]
As a result, even if the lengths of the first and second arms 1 and 2 change, an arm mechanism can be configured in which the speeds at the tip ends of the arms are almost the same. It is possible to prevent the handling from becoming difficult or increasing the risk in advance by a simple method (replacement of the gears 13 and 15).
[0018]
The drive sprocket 12 is hung on the rear side of a chain 17 having a front end coupled to the first arm 1, and a rear end side of the chain 17 is supported by a chain guide 18 provided inside the bracket member 4. By fixing 19 the rear end of the chain 17 inside the bracket member 4, an example of the drive mechanism of the present invention is formed.
[0019]
With the configuration of the drive mechanism, when the sprocket 12 is rotated forward or backward by the output of the drive source 14, the length of the chain 17 located between the connection point 16 of the chain 17 and the sprocket 12 changes. Thus, the first arm 1 of the arm mechanism aM1 can be moved upward or downward in a vertical plane, so that the entire arm mechanism aM1 can be freely moved upward or downward. Become. Then, the rotation direction and the number of rotations of the sprocket 12 are controlled so that the first and second arms 1 and 2 in the arm mechanism aM1 have a desired height, and the driving source is located at a desired position (height) of the load unit 10. When the lock 14 is locked, the arm mechanism aM1 is held in that posture.
[0020]
Since the above-described drive mechanism can be similarly performed in the arm mechanism aM2 illustrated in FIGS. 3 to 5, this point will be described next. 3 to 5, the same members and portions as those in FIGS. 1 and 2 are denoted by the same reference numerals.
[0021]
FIGS. 3 and 4 show the arrangement of the first arm 1 and the second arm 2 of the two-joint arm mechanism aM2 modified from the example of FIG. Are arranged obliquely so that the pivot points P1, P2 of the third arm 3 on the front end sides of the arms 1, 2 are parallel to the pivot points P3, P4. Formed. As a result, the third arm 3 has a substantially trapezoidal shape having a vertical bearing 8 on its front side.
[0022]
In the arm mechanism aM2 of FIGS. 3 and 4, the third arm 3 is deformed, and in particular, the pivot points P1 and P2 with the tips of the first and second arms 1 and 2 are oblique. Thereby, there is an advantage that the distal end load portion 10 of the fourth arm 9 can be positioned lower.
[0023]
In addition, in the arm mechanism aM2 of FIG. 4, the sprocket 20 is disposed at the connection point 16 of the chain 17 in FIGS. 1 and 2, and the tip end side of the chain 17 is wrapped around the sprocket 20. Is fixed 16 ′ to the bracket member 4, the magnitude of the load applied to the drive sprocket 12 can be reduced to に よ っ て by the principle of the moving pulley. FIG. 5 shows an example in which the drive source 14 is formed by a servomotor 14a, a brake 14b, and a speed reducer 14c. Further, the output gear 15 of the drive source 14 and the input gear 13 of the sprocket 12 have a configuration in which a gear ratio different from each other is appropriately selected to change the reduction rate (power increase rate). This is the same in the drive mechanism of the present invention shown in FIGS.
[0024]
FIGS. 6 and 7 show an example in which another example of the drive mechanism of the present invention is applied to the second arm mechanism aM3. The two-joint arm mechanism in FIG. 6 has first and second arms 31 and 32 that are parallel in the horizontal direction, and a third arm 33 in the vertical direction that is pivotally connected P11 and P12 to the ends of the two arms 31 and 32. Although they are common to the examples of the arm mechanisms aM1 and aM2 in FIGS. 1 to 5 described above, they are different in the following points.
[0025]
That is, in this arm mechanism aM3, (a) the rear ends P13, P14 of the first and second arms 31, 32 and the lower end of the third arm 33 are on the virtual straight line L, and (b) the second arm 32 The rear end of the first arm 31 is connected P15 to the first arm 31 by a fourth arm 34 parallel to the third arm 33. (C) The rear end P13 of the first arm 31 is connected to the vertical guide member 35 provided on the bracket member 4. (D) The rear end P14 of the second arm 32 is supported and guided by the horizontal guide member 36 provided on the bracket member 4, and (e) the load portion 10 is formed at the lower end of the third arm 33. The configuration is different from the arm mechanisms aM1 and aM2 exemplified above.
[0026]
In the arm mechanism aM3, 37 and 37 'are rolling elements such as rollers guided by the vertical guide member 35 via a roller bracket 38 provided at a rear end P13 of the first arm and a rear end P18 of an auxiliary arm 31' described later. And 39, rolling elements such as rollers guided by a guide member 36 provided at the rear end P14 of the second arm.
[0027]
The arm mechanism aM3 has the first arm 31 and the third arm 33 provided with auxiliary arms 31 'and 33', respectively, which are parallel to each other. And the extended ends of the first arm 31 are pivotally connected P16 and P17. The rear ends P18 and the lower end P19 of the auxiliary arms 31 'and 33' are held in parallel with the rear ends P13 and the lower end (the load portion 10) of the first arm 31 and the third arm 33, respectively. It is connected to.
[0028]
The above-described two-joint arm mechanism aM3 is a mechanism equivalent to a virtual constant ratio komping rod of a straight line L having the fulcrum at the rear end P14 of the second arm 32, the load point at the load unit 10, and the power point at the rear end P13 of the first arm 31. This is a two-joint arm mechanism using a pantograph mechanism.
[0029]
Therefore, when the rear end P13 of the first arm 31 is moved up and down along the vertical guide member 35, the load point 10 on the virtual straight line (operating rod) L is enlarged according to the division ratio of the straight line L by the fulcrum P14. Move up and down.
[0030]
Therefore, the following configuration is employed as the drive mechanism of the present invention applied to the arm mechanism aM3 in order to move the rear end P13 of the first arm 31 up and down along the vertical guide member 35. That is, a sprocket 40 is provided at the rear of a substantially triangular roller bracket 38 in which the first arm 31 and the rear ends P13 and P14 of the auxiliary arm 31 'are connected, and the front end of the sprocket 40 is fixed inside the bracket member 4. After the chain 17 is wound around the rear side of the chain 17, the chain 17 is wound around the drive sprocket 12 at a fixed position driven by the drive source 14, and the rear of the chain 17 after the chain 17 is wound around the guide sprocket 41. The bracket member 4 is disposed inside the bracket member 4 via the tension sprocket 42. Reference numeral 43 denotes a tension weight connected to and suspended from the tension sprocket 42, and reference numeral 44 denotes a rear end fixed point of the chain 17. The weight 43 may be replaced with a spring.
[0031]
According to the above configuration, the length of the chain 17 between the fixed point 16 ′ at the tip of the chain 17 and the driving sprocket 12 is changed by the forward or reverse rotation of the driving sprocket 12 by the output of the driving source 14, whereby the first The position of the arm rear end P13 in the vertical guide member 35 can be arbitrarily moved or positioned. Therefore, the height of the load point 10 at the lower end of the third arm 33 can be freely positioned in a range within a vertical plane in which the posture of the arm mechanism aM3 can be changed.
[0032]
Further, in the arm mechanism aM3, the rear end P14 of the second arm 32 (common to the lower end of the fourth arm 34) can be freely displaced along the horizontal guide member 38, so that the load point 10 is located within the vertical plane. You can also move back and forth with.
[0033]
The drive mechanism of the present invention includes a rear end side of a first arm for vertically moving the load unit 10 provided in the two-joint arm mechanism aM1 to aM3 described with reference to FIGS. Since the chain 17 connected to the arm 1 is moved up and down by rotating the drive sprocket 12, the drive system is configured with an existing commercially available chain 17 and the drive sprocket 12 for moving the chain. It can be formed as a basic member, whereby a drive system can be formed at a very low cost.
[0034]
The commercially available chains 17 and drive sprockets 12 are stable in quality and abundant in load bearing performance and strength from very large to small, and can be easily obtained. There is a merit that can be easily coped with even when various types are manufactured according to their load carrying capacity.
[0035]
In the present invention, the chain 17 is used as a concept including a toothed belt and a cable, and the sprocket 12 is also used as a concept including a rotating body such as a pulley corresponding to the belt and the cable. Therefore, the chain 17 and the sprocket 12 constitute the drive mechanism of the present invention even when the equivalent substitutes as described above are used.
[0036]
【The invention's effect】
The present invention is as described above, wherein a drive mechanism of a load handling device using a two-joint arm mechanism is wound around a sprocket that is rotated by a driving force of a motor or the like on a base side of an arm of the arm mechanism. The chain that moves forward and backward is linked at the forward and backward part of the chain, so it is much simpler than conventional drive mechanisms that use racks, pinions, hydraulic and pneumatic cylinders, and the structure of chains and sprockets. Since members can be used in abundant and stable quality on the market, there is an advantage that parts costs and manufacturing costs are also advantageous.
[Brief description of the drawings]
FIG. 1 is a side view for explaining a first example of a drive mechanism of the present invention applied to a first example and a two-joint arm mechanism; FIG. 2 is a plan view of FIG. 1; FIG. FIG. 4 is a side view for explaining a second example of the mechanism of the present invention applied to the mechanism. FIG. 4 is a side view for explaining a third example. FIG. 5 is a plan view of a main part of the mechanism in FIGS. FIG. 6 is a side view for explaining a fourth example of the drive mechanism of the present invention applied to the two-joint arm mechanism of the second example; FIG. 7 is a perspective view for explaining the drive mechanism of FIG. 6;
DESCRIPTION OF SYMBOLS 1 1st arm 2 2nd arm 3 3rd arm 4 Bracket member 5 Vertical axis 6 Pole 7 Support member 8 Bearing bracket 9 4th arm 10 Load application part 11 Horizontal axis 12 Drive sprocket 13 Input gear 14 Drive source 15 Output gear 16 Connection point 17 Chain 18 Chain guide

Claims (3)

A first arm and a second arm that are parallel in the horizontal direction are pivotally attached to a bracket member at the base sides of the two arms or provided so as to be guided and held by a straight guide, and are vertically oriented toward the distal ends of the two arms. In a two-joint arm mechanism having a third arm provided and a load applying portion provided at the distal end side of the third arm, the support portion at the base side of one of the first and second arms is vertically swung up and down. A two-joint, wherein a chain which is wound around a sprocket rotated by a driving force of a motor or the like and moves forward and backward is connected to a root side of any one of the arms at a forward and backward portion of the chain. Arm drive mechanism of the arm mechanism. 2. The two-joint arm mechanism in which the root sides of the first and second arms are pivotally connected to a bracket member, wherein a chain advancing / retreating part is linked forward or rearward with respect to a pivot point of the first arm or the second arm. An arm drive mechanism of a two-joint arm mechanism. In the two-joint arm mechanism in which the root sides of the first and second arms are slidably supported by a linear guide provided on the bracket member, the forward / backward portion of the cord body is provided at the root of the arm supported by the vertical linear guide. The arm drive mechanism of the two-joint arm mechanism according to claim 1, wherein

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