JPH0699119B2 - Balance adjuster - Google Patents

Description

TECHNICAL FIELD The present invention relates to a balance adjusting device, and more particularly to a balance adjusting device applied to a cargo handling / transporting device, a robot and the like.

[Conventional technology]

For example, in an elevator or the like, as shown in FIG.
When the load 12, which is a car, is moved up and down by the rotation of the pulley 26, there is a counterweight 28 that balances the load 12 through the pulley 26 and another pulley 27.

In this case, the weight of the counter weight 28 is equal to the load 12
Considering the fluctuation of 29, the following values are set.

Here, Wb is the weight of the counter weight 28, Wa is the load weight, and W _L is the load fluctuation weight.

However, when the load is moved up and down by a driving device (not shown), the maximum driving force F spent on it is F = (Wa + W _L + W _B ) / g × α, which is a wasteful driving force as the inertia increases. It was something I needed. Here, g is gravitational acceleration,
α is a motion acceleration.

As another conventional technique, as shown in FIG. 4, the pulleys 4 and 5 are provided at the end of the piston that moves up and down by the supply of hydraulic pressure into the cylinder, and the pulley 6 is provided below the cylinder to suspend the load 12. There is one in which the rope 9 is sequentially wound around the pulleys 5, 6 and 4 and the other end is fixed. Hydraulic pressure is supplied to the cylinder from a hydraulic unit 30, and the hydraulic unit 30 includes an oil tank 31 and a strainer.
32, hydraulic pump 33, switching valve 34, muffler 35, drain pipe 36
It is composed of.

[Problems to be solved by the invention]

However, in the configuration shown in FIG. 4, when the load 12 is lowered (the direction of the broken line arrow in the figure), the working oil in the cylinder is collected in the oil tank 31 via the muffler 35 and the drain pipe 36. However, the process of performing the process causes a loss of hydraulic energy.

The present invention has been made based on such circumstances,
It is an object of the present invention to provide a balance adjusting device that can store energy once input and can have a balance function in a wide load operating range.

[Means for solving problems]

In order to achieve such an object, the present invention provides a pressure-force converter that has one end fixed and outputs a force corresponding to a pressure value to an operating end that can move forward and backward with respect to the fixed end, and the pressure-force converter. At least one shaft is supported on the fixed end side of the converter, and one pulley is supported on the working end so as to be able to move forward and backward together with the working end by one more, and one end is fixed by being wound around each pulley. The other end is provided with a rope which is connected to a load and is always strained, and a pressure accumulator tank connected to the pressure supply side of the pressure-force converter, in which the compressible fluid is a check valve and pressure setting. It is designed such that it is supplied via a valve and is provided with an overpressure release valve.

[Action]

In the balance adjusting device configured as described above, the pressure / force conversion device configured to support the force of the load via the pulley has the pressure storage side connected to the pressure supply side. The force converted by the force converter is substantially constant regardless of the fluctuation of the load. Here, the accumulator tank has a larger volume than the pressure chamber in the pressure / force converter, and the larger the volume, the smaller the fluctuating pressure range.

Here, the relationship between the pressure in the accumulator tank 14 having a relatively small volume and the stroke of the working end of the pressure / force conversion device including the cylinder 1 will be described with reference to FIG. The original pressure supplied to the cylinder 1, that is, the pressure of the compressive fluid 17 in the figure is Po, the opening pressure at the time of overpressure, that is, the pressure value for relief for safety when the internal pressure becomes high, P _A , the maximum pressure in the cylinder, That is, the maximum internal pressure generated in the retracted state due to the piston movement of the cylinder is Pmax. The enclosed pressure between the position S where the cylinder is most contracted and the position Sa where it is most extended can be set so as to exist within the region surrounded by the triangles 19, 20, 21 in the graph in the figure. Also, when the effective stroke is set within the stroke range of S ₁ , which has a margin relative to the full stroke So of the cylinder, the filling pressure is the quadrangle 22, 23, 2 in the graph in the figure.
It is unavoidable that it exists in the area surrounded by 4,25 and is accompanied by a pressure fluctuation such as the curve 26.

The supply of the compressed fluid 17 is not necessary if there is no leakage from the seal portion of the cylinder.

Therefore, by increasing the volume of the accumulator tank sufficiently larger than that of the cylinder, the pressure Pmax
It becomes closer to Po (Pmax≈Po), and as a result, it is possible to always generate a constant pressure regardless of the fluctuation of the stroke of the cylinder, and it is possible to eliminate the fluctuation of the balance force.

Further, the force of the pressure / force converter acting as a reaction force of the force exerted by the load becomes a value equal to or larger than the load due to the pulley that winds the rope connected to the load, and the force of the pressure / force converter of that amount is increased accordingly. The stroke of the working end can be smaller than the displacement of the load. When the stroke of the working end of the pressure / force converter is limited, the number of pulleys may be increased and the set pressure value in the pressure accumulator tank may be increased accordingly.

〔Example〕

FIG. 1 is a block diagram showing an embodiment of a balance adjusting device according to the present invention. In the figure, there is a load 12, and a force acts in the direction of the dotted arrow in the figure, and the load 12 is displaced in the direction of the solid line arrow in the figure by a drive device (not shown) such as a motor. ing. And the rope 9 is connected in this displacement direction, and this rope 9 is connected to the pulley 5,
They are respectively wound around 6 and 4 and connected to the fixing member 10 on the side of the load 12. The pulley 7 is rotatable in a fixed state, and the pulleys 4 and 5 are coaxial with each other and can be displaced with respect to the pulley 6 in the displacement direction of the load 12.

Further, the loosening of the rope 9 due to the movement of the load 12 in the direction of the solid line arrow in the figure causes the pulleys 4 and 5 to move the load 12 by the force at the operating end of the pressure / force converter attached to the shafts of the pulleys 4 and 5.
It is prevented by displacing in the displacement direction, and the tension state is maintained.

The pressure / force conversion device includes a cylinder 1 and a piston 2, and the shaft of the piston 2 corresponds to the working end. The cylinder 1 is fixed, and its pressure chamber is connected to a pressure accumulator tank 14 via a pipe 13. The volume of the accumulator tank 14 is sufficiently large (nV) with respect to the volume (V) of the pressure chamber of the cylinder 2.

A compressive fluid 17 is supplied to the pressure accumulating tank 14 via a check valve 15 and a pressure setting valve 16, and the inside of the pressure accumulating tank 14 is maintained at a pressure value set by the pressure setting valve 16. Has been done.

This pressure value is increased by the pulleys 4, 5 and 6 to the force required to displace the force acting on the shaft of the piston 2 of the cylinder 1 in the direction of the arrow of the load 12 (in the case of the figure, Is increased four times), and it is desirable to set so as to balance with the amount of force.

The operation of the balance adjusting device thus configured will be described below. The pressure in the accumulator tank 14 becomes the pressure in the pressure chamber of the cylinder 1 as it is via the pipe 13. Due to this pressure, a force in the direction of the solid arrow in the figure (for example, a force of 4 W) is applied to the shaft of the piston 2.
Works. This force causes the pulleys 4 and 5 that are coaxial with each other to act in a direction away from the pulley 6 (this pulley 6 is fixed), that is, in the direction of the solid line arrow in the figure, and as a result, the rope connected to the load 12 side The force of W acts on 9. When the load 12 is constantly biased by the force W in the direction of the dotted line in the drawing, the energy required by the driving device is extremely large when the load is displaced in the direction of the solid line by the driving device (not shown). It will be few.

In this case, the stroke of the shaft of the piston 2 changes with the displacement of the load 12, but since the pressure chamber of the pressure chamber of the cylinder 1 is connected to the accumulator tank whose volume is much larger than its capacity, the pressure value Does not change significantly, so that the force W acting on the shaft of the piston 2 remains unchanged.

Further, the displacement amount of the shaft of the piston 2 connected to the shafts of the pulleys 4 and 5 is smaller than the displacement amount of the load 12 (reduced to 1/4 in the case of the figure).

FIG. 5 is a configuration diagram showing another embodiment of the balance adjusting apparatus according to the present invention, and particularly shows a case where the balance adjusting apparatus is used for an elevator apparatus.

In the figure, there is a load 12 consisting of an elevator car,
The load 12 is suspended by a rope 9-a via a fixture 11-a. The rope 9-a is wound up by a drum 39 attached to a rotary shaft 38 of a driving device 40 including a motor. Another drum 37 is attached to the rotary shaft 38 of the drive unit 40. The rope 9 having one end fixed to the drum 37 is further wound around the drum 37 and the other end is attached to the drum 37. It is connected to the fixed portion 10 via pulleys 4, 5 and 6 of the mechanism shown in FIG.

The winding direction of the rope 9 around the drum 37 is different from the winding direction of the rope 9-a around the drum 39.
It is suspended in the load direction and wound around the pulley 5. A force is applied to the pulleys 5 and 4 by the piston shaft of the cylinder 1 in the downward direction in the drawing, and the force is applied in the winding direction of the rope 9-a by the drive device 40.

FIG. 6 is a block diagram showing still another embodiment of the balance adjusting apparatus according to the present invention. In the figure, there is a hand 44 that holds a work 45, and this work 44 is a column post 41.
Are provided integrally. A rack 42 is formed on the longitudinal side surface of the column post 41.
A pinion 43 attached to the rotary shaft of the drive device 40 is meshed with the. Further, one end of a rope 9 is connected to a lower end of the column post 41 on the hand 44 side, and the rope 9 is stretched upward along the column post 41.
The fixed portion 10 is wound around the pulleys 4, 5 and 6 of the mechanism shown in FIG.
It is connected to the. The pulleys 5 and 4 are arranged above the pulley 6, and when the column post 41 moves upward, the pulleys 5 and 4 are moved upward by the action of the force from the piston shaft of the cylinder 1. It has become.

FIG. 7 is a block diagram showing still another embodiment of the balance adjusting apparatus according to the present invention, which is applied to a multi-joint arm type robot.

In the figure, a parallelogram link having joints B, C, D, E is provided, and each piston axis of cylinders 46, 47 is pivotally supported by an extension portion F of the link between joints C, E. The cylinders 46 and 47 are swingably mounted, and by supplying an arbitrary pressure to them, the extension point A of the link between the joints C and B can be moved to a predetermined position.

Further, a rope 9 is connected to the extending portion F of the link and wound around the pulleys 4, 5 and 6 of the mechanism shown in FIG. 1 via the pulley 5-1.

〔The invention's effect〕

As is clear from the above description, according to the balance adjusting device of the present invention, it is possible to store energy that has been input once, and to have a balance function in a wide load operating range, and Since pressure fluctuations are small, fluctuations in positioning accuracy due to load movement are reduced.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of a balance adjusting device according to the present invention, FIG. 2 is an explanatory view showing the operation of the balance adjusting device according to the present invention, and FIGS. 3 and 4 are conventional balance adjusting devices. 5 to 7 are configuration diagrams showing the side of FIG.
Each of the drawings is a configuration diagram when the balance adjusting device according to the present invention is applied to various devices. 1 ... Cylinder, 4,5,6 ... Pulley, 9 ... Rope, 12 ... Load, 14 ... Accumulator, 15 ... Check valve, 16 ... Pressure setting valve, 17 ... Compressible fluid .

Claims (1)

[Claims] Claim: What is claimed is: 1. A pressure-force converter which has a fixed end and outputs a force corresponding to a pressure value to an actuating end that can move forward and backward with respect to the fixed end, and at least one pressure-force converter on the fixed end side.
A pulley that is individually pivoted and has one more movable end on the working end side than the fixed end side, and a pulley that is pivotally supported together with the working end, and one end that is wound around each pulley and the other end is connected to the load and is always A tensioned rope and a pressure accumulation tank connected to the pressure supply side of the pressure-force converter are provided, and the pressure accumulation tank is configured so that the compressive fluid is supplied via a check valve and a pressure setting valve. The balance adjustment device is characterized by being equipped with an overpressure release valve.