CN109723759B - Tendon transmission locking tool - Google Patents
Tendon transmission locking tool Download PDFInfo
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- CN109723759B CN109723759B CN201711037540.7A CN201711037540A CN109723759B CN 109723759 B CN109723759 B CN 109723759B CN 201711037540 A CN201711037540 A CN 201711037540A CN 109723759 B CN109723759 B CN 109723759B
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Abstract
The invention belongs to the technical field of multi-degree-of-freedom mechanisms and micro-transmission control, and particularly relates to a multi-degree-of-freedom transmission mechanism mainly based on tendon transmission, which realizes a tendon transmission locking tool for reducing transmission errors in a high-efficiency and accurate tendon transmission fixing mode; comprises a left push rod (1), a through hole (2), a base fixing bolt (3), a supporting seat (4), a tapered hole (5), an extruded metal block (6), a right flexible push rod (7) and an anti-destabilization sleeve (8); the hydraulic power system is fixed on the supporting seat (4) through a base fixing bolt (3), the anti-instability sleeve (8) is embedded into a right side mounting hole of the supporting seat (4), and a left push rod (1) is arranged on the left side of the supporting seat opposite to the instability sleeve (8); the extruded metal block (6) is arranged on the anti-instability sleeve (8); a conical hole (5) is formed in the supporting seat (4); the right flexible push rod (7) is arranged on the right side of the instability sleeve (8).
Description
Technical Field
The invention belongs to the technical field of multi-degree-of-freedom mechanisms and micro-transmission control, and particularly relates to a tendon transmission locking tool.
Background
In the field of multi-degree-of-freedom mechanisms and micro-transmission control, although the traditional transmission modes such as gear racks, worm gears, harmonic waves and the like have higher transmission efficiency and accurate transmission ratio, the traditional transmission modes are constrained by larger overall dimension and the fact that a micro motor is integrated in a joint micro space and cannot provide enough output force, and the traditional transmission modes are a main bottleneck for restricting the development of micro-transmission control technology. Therefore, the transmission in a limited space by a flexible tendon or a flexible steel wire rope is a very effective transmission mode. The fixing mode of the transmission tendon influences the transmission efficiency of the mechanism to a great extent, the steel wire rope is fastened by using the plastic deformation of high-rigidity metal, so that enough holding force can be provided for the flexible tendon, the overall dimension of the fastening block can be accurately controlled, and compared with the knotting mode of the steel wire rope, the method can well ensure the strength and the assembly precision of the rope, eliminate the gap and realize precise transmission.
At present, in the field of motion control of robot mechanisms, the robot mechanisms are developing towards miniaturization and microminiaturization, in order to save space, a plurality of robot joints are controlled in a tendon transmission mode, drivers are arranged outside, and long-distance power transmission is carried out through structures of transmission tendons such as flexible steel wire ropes. The rope fixing mode directly influences the stability and transmission precision of a transmission system, and the rope knotting mode is generally adopted at home and abroad at present, however, the method has two defects: 1. the knotted size of the rope is uncontrollable, the knotted rope is irregular in shape, a gap error is inevitably generated in a transmission chain, and the precision of a transmission system is greatly reduced due to the inherent flexible link of the rope; 2. the tied-up point of the rope will move along the rope when being under tension, so that the transmission system is unstable and the rope can be loosened. If the ropes are fixed by welding, on the one hand, they are subjected to a secondary heat treatment which reduces their strength, and on the other hand, in the case of very thin drive tendons, welding can lead to rope breakage. Therefore, the invention provides a transmission tendon which is locked in a mechanical clamping mode, so that the high reliability of a rope is guaranteed, meanwhile, the overall dimension of a locking node can be accurately controlled, the transmission error is reduced, and the transmission system is guaranteed to have an accurate transmission ratio.
The tendon transmission locking tool system comprises a base with a tapered hole, a flexible push rod with a variable diameter, a rigid push rod, an anti-instability sleeve, a hydraulic power source and the like, and is shown in figure 2. The function is that the metal cylinder block with the central through hole (the flexible transmission tendon passes through the central hole) is pushed to one side of the small diameter of the taper hole from the large diameter end of the taper hole of the base along the axial direction by the flexible push rod, and in the moving process, the cylindrical metal block with the hole is forced to generate plastic deformation due to the fact that the periphery and the end face of the cylindrical metal block are all pressed, so that the inner wall of the central hole is contracted, the hole diameter is reduced, the transmission tendon is tightly held, the purpose of fastening a rope is achieved, meanwhile, the overall dimension of the metal block for locking the transmission tendon can be accurately controlled, the tendon transmission system is guaranteed to have more accurate transmission ratio, and transmission.
Disclosure of Invention
The invention aims to provide a multi-degree-of-freedom mechanism mainly based on tendon transmission, which is particularly suitable for precision transmission in a micro space, ensures that a tendon transmission system has a more accurate transmission ratio and reduces transmission errors.
The technical scheme of the invention is as follows:
a tendon transmission locking tool comprises a left push rod, a through hole, a base fixing bolt, a supporting seat, a tapered hole, an extruded metal block, a right flexible push rod and an anti-instability sleeve; the hydraulic power system is fixed on the supporting seat through a base fixing bolt, the anti-instability sleeve is embedded into a right mounting hole of the supporting seat, and a left push rod is arranged on the left side of the supporting seat opposite to the instability sleeve; the extruded metal block is arranged on the anti-destabilizing sleeve; a conical hole is formed in the supporting seat; the right flexible push rod is arranged on the right side of the instability sleeve.
And through holes are formed in the left push rod and the right flexible push rod.
The end part of the left push rod is positioned at the edge of an inner hole of the right instability sleeve.
A rope is arranged at the front section of the extruded metal block and is led out through the center hole of the left push rod;
and the right flexible push rod is provided with a cross groove along the axial direction.
The invention has the beneficial effects that:
1. the flexible push rod with the variable diameter can be used for self-adapting to the diameter change of the metal block which is subjected to plastic deformation;
2. the double push rods work in a reciprocating mode in a coordinated mode, so that the stability of the movement of the metal block in the tool is guaranteed, and the working efficiency of the metal block extrusion test is improved;
3. the size of the tapered hole in the tool can be flexibly changed according to the requirements of different application occasions and installation spaces, the flexible tendon locking blocks with different sizes can be manufactured, and the flexible tendon locking blocks and other transmission mechanisms are installed and matched with each other to achieve high accuracy.
Drawings
FIG. 1 is a schematic view of a multiple degree of freedom mechanism;
FIG. 2 is a schematic view of a flexible drive tendon;
FIG. 3 is a schematic view of a tendon-driven locking tool;
FIG. 4 is an assembly view of a variable diameter flexible push rod;
FIG. 5 is a schematic view of a cross slot;
FIG. 6 is a graph I of the change in the geometrical dimensions of the metal block before and after plastic deformation
FIG. 7 is a graph II of the change in the geometrical dimensions of the metal block before and after plastic deformation
Fig. 8 is a view showing the structure of the extrusion passage.
Detailed Description
The invention will be further described with reference to the following figures and examples:
a tendon transmission locking tool comprises a left push rod 1, a through hole 2, a base fixing bolt 3, a supporting seat 4, a conical hole 5, an extruded metal block 6, a right flexible push rod 7 and an anti-instability sleeve 8; the support seat 4 is welded on the bottom plate, the hydraulic power system is fixed on the support seat 4 through the base fixing bolt 3, the anti-instability sleeve 8 is embedded into the right mounting hole of the support seat 4, and the left push rod 1 is arranged on the left side of the support seat opposite to the instability sleeve 8; the extruded metal block 6 is arranged on the anti-instability sleeve 8; a tapered hole 5 is formed in the supporting seat 4; the right flexible push rod 7 is arranged on the right side of the instability sleeve 8.
And through holes 2 are formed in the left push rod 1 and the right flexible push rod 7.
The end part of the left push rod 1 is positioned at the edge of the inner hole of the right instability sleeve.
The front section of the extruded metal block 6 is provided with a rope which is led out through the central hole of the left push rod 1.
The right flexible push rod is provided with a cross groove along the axial direction, the strength of the push rod is ensured, and meanwhile, the end part shaft diameter is variable, so that the inner diameter of the taper hole is self-adaptive, and the outer diameter of the metal block is continuously and stably contacted with the end face of the metal block in the continuous shrinkage process, and constant and unchangeable thrust is provided. As shown in fig. 3.
The tooling design process requires quantitative risk analysis for two problems: 1. analyzing the deformation of the extruded metal block and the tension risk of the steel wire rope; 2. the stability of the compression bar of the flexible variable diameter push rod extruding the metal block is analyzed.
(1) Checking tensile stress of rope
According to ideal geometric analysis, in the process of shrinking the inner hole after the metal block is pressed, the volume change quantity caused by the shrinkage of the outer diameter is equal to the volume change of the shrinkage of the central hole, and the central hole is filled. In order to increase the holding force of the flexible tendon as much as possible, the compression amount of the metal block may be increased by a few times, but the metal block may be elongated longitudinally, and the geometric principle is shown in fig. 4.
According to the principle of conservation of total volume:
wherein, Delta is the axial elongation of the metal block.
In the compression process, the left push rod and the right push rod always keep certain clamping force to inhibit the extension of the metal block, so that in the process, the plastic deformation of the metal block firstly occurs in the pore diameter shrinkage and then occurs in the axial stretching. Therefore, it is necessary to check the relationship between the strain caused by the axial elongation of the metal block and the resulting stress and the nominal tensile strength of the flexible tendon, and the following relationship must be satisfied:
in this case, the metal block can provide a sufficient holding force without damaging the flexible tendon.
(2) Compression bar stability analysis for flexible variable diameter push rods
As the flexible push rod can be regarded as a compression rod with one fixed end and one free section, the section of the compression rod is four quarter circles, as shown in figure 3. Therefore, the critical force of the strut is calculated:
section moment of inertia:
wherein E is the elastic modulus of the flexible tendon material; l is the length of the compression bar.
Due to the pressed area of the metal block:
according to the yield strength sigma of the metal block to be extruded0.2The minimum thrust force F required by the push rod is calculated and must satisfy:
σ0.2×S＜F＜Pij
and finally calculating according to the inequality to determine the length of the flexible variable-diameter push rod.
The core technology of the flexible steel wire rope fastening tool comprises the following steps: 1. a flexible variable diameter push rod; 2. a smooth tapered hole with a slight taper; 3. the left and right push rods can work in a reciprocating way. As shown in fig. 2.
The center of the metal block is penetrated with a flexible steel wire rope, and the centers of the push rods at two sides are provided with rope guide through holes in order not to damage the rope in the extrusion process. As shown in fig. 5. The coaxiality of the anti-instability sleeve, the conical hole and the cylindrical hole needs to be strictly ensured by the tool, the metal block can stably pass through the tool, and the posture deflection cannot occur.
The left and right push rods can provide enough thrust through a hydraulic system, and the design of the hydraulic cylinder and the piston rod is carried out according to the material yield limit of the extruded metal block. Because the experimental process can produce great thrust, in order to guarantee the reliability of frock, carry out special requirement to the material of key part wherein:
hardness relationship: housing base > push rod > extruded metal block.
The tendon transmission locking tool system comprises a base with a conical hole, a flexible push rod with a variable diameter, a rigid push rod, an anti-instability sleeve, a hydraulic power source and the like. The center of the metal block is penetrated with a flexible steel wire rope, and in order not to damage the rope in the extrusion process, the centers of the push rods at the left side and the right side are provided with rope guide through holes, as shown in figure 5. The coaxiality of the anti-instability sleeve, the conical hole and the cylindrical hole needs to be strictly ensured by the tool, the metal block can stably pass through the tool, and the posture deflection cannot occur.
The requirement on the smooth finish and the roughness of the inner surface of the tapered hole of the supporting base is high, the supporting base has high enough hardness and strength, the inner surface of the tapered hole cannot be scratched in the compression deformation process of the metal block, and the supporting base cannot be bent or broken. The supporting base is connected with the supporting bottom plate in a spot welding mode.
The diameter-variable flexible push rod is axially provided with a cross groove in a linear cutting mode, the groove width is determined according to the shrinkage of a pressed metal block, so that the end part of the push rod is also radially shrunk due to the shrinkage of the aperture in the process that the push rod enters the tapered hole to adapt to the size of the tapered hole, and finally the metal block which is subjected to plastic deformation is smoothly extruded into the cylindrical through hole on the small-diameter side of the tapered hole.
Because the coaxial precision of hole, push rod need be guaranteed constantly at the course of the work to this frock, and the pneumatic cylinder piston rod of external hydraulic power source is because the sealing washer has elasticity for the movement track of piston rod when the atress probably has axial skew, if direct and the left and right push rod rigid connection of frock system, probably leads to the push rod to bear great bending stress, and then arouses the push rod fracture. Therefore, the external hydraulic power source and the left and right push rods are subjected to non-fixed connection type collision extrusion, the mounting precision requirement of the power source and the tool is reduced, the push rods move along the guide grooves in the tool, and overlarge bending stress is avoided.
The tendon transmission locking tool is characterized in that:
(1) the flexible push rod with the variable diameter utilizes the flexible deformation of the push rod to adapt to the change of the inner diameter of the tapered hole and always keeps in contact with the end face of the metal block which is subjected to plastic deformation, so that the guiding precision can be improved under the action of the anti-instability sleeve, meanwhile, the flexible push rod is ensured not to be subjected to instability, and the thrust force enough for forcing the metal block to be subjected to plastic deformation is provided.
(2) The taper hole is provided with a small taper with a smooth inner surface, and the taper hole, the cylindrical through holes on two sides and the external anti-instability sleeve have high coaxiality.
(3) The left and right push rods can realize reciprocating work. Because the metal takes place plastic deformation and gets into the cylindric hole of minor diameter, have great pressure between its and the frock internal surface, if want to take out the metal block and need overcome very big frictional force this moment, consequently, drive the rigidity push rod of left end through hydraulic power source and exert thrust, can push out the metal block after the pressurized together with the steel wire rope of holding tightly from the right-hand member of frock, improve the work efficiency of metal block extrusion test.
In the initial working stage of the system, the extruded metal block is positioned at the junction of the anti-instability sleeve and the large diameter of the tapered hole, the rigid push rod on the left side and the flexible push rod on the right side are in contact with the two end faces of the cylindrical metal block, and a certain load force is applied through an external hydraulic power source to ensure that the stress balance of the metal block reaches a stable posture state.
And then, in a first working stage, the thrust of the left push rod and the thrust of the right push rod are increased to the yield limit of the metal block through a hydraulic source, the thrust of the right flexible push rod is ensured to be slightly larger than that of the left push rod, so that the cylindrical metal block threaded with the steel wire rope slowly enters the middle conical hole along the axial direction, the metal block is subjected to plastic deformation along with the contraction of the diameter of the conical hole, and the end face of the flexible push rod can contract along the radial direction after being extruded by the inner wall of the conical hole due to the fact that the flexible push rod is provided with. The rope is held tightly gradually along with the pressurized on four sides to the metal block at the in-process of motion, finally gets into left concentric cylinder through-hole, and the push rod is keeping invariable pressure difference throughout about this stage, guarantees that the metal block slowly passes through the bell mouth, avoids the metal block to receive the extrusion and extends simultaneously again for the hole of metal block is fully filled to plastic deformation's decrement, holds the inside transmission tendon tightly.
And finally, in the third stage of the system operation, after the metal block is plastically deformed, the left through hole of the tensioning base is tightened, the metal block is not easy to take out due to overlarge friction force, the right flexible push rod releases pressure, and the left hydraulic power source drives the rigid push rod to push the metal block tightly holding the flexible steel wire rope out to the right.
Examples
During assembly, the supporting base and the supporting bottom plate are connected in a spot welding mode, and the base and the bottom plate are guaranteed to be perpendicular to each other.
And then, the hydraulic power system is fixed through a base fixing bolt, so that the output end of the hydraulic source and the tapered hole of the support base are approximately in the coaxial position.
Thirdly, the anti-instability sleeve is embedded into the right mounting hole.
Fourthly, a left rigid push rod is installed, so that the end of the left rigid push rod just reaches the edge of the inner hole of the right anti-instability sleeve.
Fifthly, a metal block penetrated with a flexible tendon is arranged in the anti-instability sleeve, and a rope at the front end is led out through a central hole of the left rigid push rod.
And sixthly, penetrating the flexible tendon at the other end into a central hole of the flexible push rod with the variable diameter, and installing the push rod into the instability prevention sleeve.
Finally, the flexible tendon is tensioned, and the left and right push rods clamp the metal block.
During the experiment, firstly, the hydraulic sources on the two sides of the push rod are simultaneously adjusted to apply a certain pretightening force, a certain fastening force is kept between the rigid push rod and the flexible push rod with the variable diameter, the metal block is clamped, and the position is kept unchanged.
Then, the flow of a hydraulic source outside the flexible push rod is increased through the pressure regulating valve, the right thrust is increased, the metal block is stably pushed into the tapered hole, and in the process, the flow direction of the hydraulic source on the left side is regulated, so that the hydraulic source and the flexible push rod synchronously contract backwards while keeping a certain clamping force on the metal block until the metal block is subjected to plastic deformation and completely enters the cylindrical through hole with the smaller diameter on the left side.
And finally, respectively relieving pressure of the right hydraulic source and pressurizing the left hydraulic source through a flow valve, and pushing the metal block together with the flexible push rod out of the large-diameter side of the tapered hole by utilizing the rigid push rod.
Claims (4)
1. The utility model provides a driven locking frock of tendon which characterized in that: comprises a left push rod (1), a through hole (2), a base fixing bolt (3), a supporting seat (4), a tapered hole (5), an extruded metal block (6), a right flexible push rod (7) and an anti-destabilization sleeve (8); the hydraulic power system is fixed on the supporting seat (4) through a base fixing bolt (3), the anti-instability sleeve (8) is embedded into a right side mounting hole of the supporting seat (4), and a left push rod (1) is arranged on the left side of the supporting seat opposite to the instability sleeve (8); the extruded metal block (6) is arranged on the anti-instability sleeve (8); a conical hole (5) is formed in the supporting seat (4); the right flexible push rod (7) is arranged on the right side of the instability sleeve (8); a flexible steel wire rope penetrates through the center of the extruded metal block (6), and rope guide through holes are formed in the centers of the push rods on the left side and the right side; the right flexible push rod (7) is a flexible push rod with a variable diameter; the right flexible push rod (7) is provided with a cross groove along the axial direction, the groove width is determined according to the shrinkage of the pressed metal block, the end part of the push rod is also shrunk along the radial direction due to the shrinkage of the aperture in the process that the right flexible push rod enters the tapered hole so as to adapt to the size of the tapered hole, and the metal block with plastic deformation is extruded into the cylindrical through hole on one side of the tapered small hole; the contact force for resisting the plastic deformation of the metal block is always kept constant among the right flexible push rod (7), the extruded metal block (6) and the left push rod (1) in the extrusion motion process.
2. The tendon-driven locking tool of claim 1, wherein: and through holes (2) are formed in the left push rod (1) and the right flexible push rod (7).
3. The tendon-driven locking tool of claim 1, wherein: the end part of the left push rod (1) is positioned at the edge of an inner hole of the right instability sleeve.
4. The tendon-driven locking tool of claim 1, wherein: ropes are arranged at the front section and the center of the extruded metal block (6) and are led out through the center holes of the left push rod (1) and the right flexible push rod (7).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711037540.7A CN109723759B (en) | 2017-10-30 | 2017-10-30 | Tendon transmission locking tool |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201711037540.7A CN109723759B (en) | 2017-10-30 | 2017-10-30 | Tendon transmission locking tool |
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| CN109723759A CN109723759A (en) | 2019-05-07 |
| CN109723759B true CN109723759B (en) | 2021-02-09 |
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Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE20108139U1 (en) * | 2001-05-14 | 2002-09-19 | Diehl Metall Stiftung & Co Kg | clamping device |
| CN202560930U (en) * | 2012-05-15 | 2012-11-28 | 张旭民 | Simple and practical steel cable opening socket device |
| CN203413037U (en) * | 2013-07-02 | 2014-01-29 | 徐工集团工程机械股份有限公司 | Detachable rope end fixing device and auxiliary stringing device |
| CN104179886A (en) * | 2013-05-20 | 2014-12-03 | 极东钢弦混凝土振兴株式会社 | Anchoring device for fiber reinforced plastic composite cable |
| WO2015195278A1 (en) * | 2014-06-19 | 2015-12-23 | Hood Technology Corporation | Rope termination forming system |
| CN106219357A (en) * | 2016-07-22 | 2016-12-14 | 山东泰安煤矿机械有限公司 | The rope Locking device of well lifter suspension arrangement is erect for mine |
| CN106438843A (en) * | 2016-11-30 | 2017-02-22 | 南京海獭软件有限责任公司 | Steel wire butt joint connecting device |
-
2017
- 2017-10-30 CN CN201711037540.7A patent/CN109723759B/en active Active
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE20108139U1 (en) * | 2001-05-14 | 2002-09-19 | Diehl Metall Stiftung & Co Kg | clamping device |
| CN202560930U (en) * | 2012-05-15 | 2012-11-28 | 张旭民 | Simple and practical steel cable opening socket device |
| CN104179886A (en) * | 2013-05-20 | 2014-12-03 | 极东钢弦混凝土振兴株式会社 | Anchoring device for fiber reinforced plastic composite cable |
| CN203413037U (en) * | 2013-07-02 | 2014-01-29 | 徐工集团工程机械股份有限公司 | Detachable rope end fixing device and auxiliary stringing device |
| WO2015195278A1 (en) * | 2014-06-19 | 2015-12-23 | Hood Technology Corporation | Rope termination forming system |
| CN106219357A (en) * | 2016-07-22 | 2016-12-14 | 山东泰安煤矿机械有限公司 | The rope Locking device of well lifter suspension arrangement is erect for mine |
| CN106438843A (en) * | 2016-11-30 | 2017-02-22 | 南京海獭软件有限责任公司 | Steel wire butt joint connecting device |
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| CN109723759A (en) | 2019-05-07 |
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