JPH0228727B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a reciprocating actuator that utilizes a rodless hydraulic cylinder.

[Prior Art] For example, when automatically opening and closing the door of a machining center or when moving various work devices in the X-Y two-dimensional direction, an actuator that moves a movable member back and forth between two positions is used. ing. Conventionally, actuators for reciprocating motion that utilize fluid pressure cylinders without rods have been known (for example,
(Refer to Publication No. 16165 and Japanese Patent Publication No. 50-25992). An example of this is shown in FIG.

In FIG. 4, a piston 02 is provided within a cylinder 01 and is driven reciprocally by pressure fluid. A driven body 03 disposed outside the cylinder 01 is reciprocated by a moving force transmission mechanism 04 driven by the reciprocating motion of the piston 02.

Since this type of actuator does not have a rod, the pressure receiving area of the piston 02 is large, so the bore diameter can be made small, and the cylinder can be shortened in the axial direction, so it has the advantage of being compact.

[Problems to be Solved by the Invention] However, in the conventional example, the moving force transmission mechanism 0
4 is constructed of wire or steel strip.
Therefore, the wire 04 and the like elongate over time due to the repeated action of tensile stress during the movement of the piston 02, and the influence of thermal expansion due to temperature changes is large. Therefore, the motion performance such as the speed of the driven body 3 cannot be stably maintained over a long period of time.

Therefore, as disclosed in Japanese Patent Application Laid-Open No. 57-149603, a ball pivot chain is connected to the tip of a connector of a piston, and the ball pivot chain is guided by four connecting bolts, thereby transmitting the moving force. It is also conceivable to configure mechanism 04.
In this case, the effects of the deformation and thermal expansion over time can be reduced, and the motion performance such as the speed of the driven body 03 can be maintained stably over a long period of time.

However, in this configuration, the piston connector and the ball pivot chain are in spherical surface contact with each other, so the pressure receiving area of the piston is reduced. Therefore, it becomes necessary to increase the bore diameter of the cylinder 01, which results in the disadvantage that the entire actuator becomes larger.

In view of the above circumstances, an object of the present invention is to provide a reciprocating actuator using a fluid pressure cylinder that can maintain stable motion performance over a long period of time and is free from the risk of increasing in size.

[Means for Solving the Problems] In order to achieve the above object, the reciprocating actuator using a fluid pressure cylinder according to the present invention is first formed between the driven body 3 and the piston 2. The moving force transmission mechanism 4 is composed of a bending path 5 and a large number of spheres 6 having the same diameter arranged in the bending path 5 and pressed against each other. Furthermore, a straight path 5C located inside the cylinder 1 among the bent paths 5 communicates with the cylinder chambers 1A and 1B,
A cylindrical seal member 13 with which the sphere 6 slides is provided outside the cylinder 1 in the bending path 5 .

[Operation] According to the reciprocating actuator using a fluid pressure cylinder according to the present invention, as the piston 2 is driven, a compressive force acts on the sphere 6, and the moving force of the piston 2 is applied to the driven body 3. communicated. here,
Unlike a wire or the like, the spherical body 6 has a large spring constant, so it is unlikely to be deformed over time even if a moving force is applied repeatedly. Further, since the thermoelastic coefficient of the sphere 6 is smaller than that of a wire or the like, expansion etc. due to temperature changes can be suppressed.

Further, among the bent paths 5, the straight path 5C in the cylinder 1 communicates with the cylinder chambers 1A and 1B to form the cylinder chambers 1A and 1B, so that pressure fluid is also introduced into the straight path 5C, and Since the sphere 6 makes point contact with the piston 2, the pressurizing force of the pressurized fluid is applied to almost all sides of the piston 2. In other words, even if the sphere 6, which is a moving force transmission medium, is in pressure contact with the piston 2, the pressure-receiving area of the piston 2 hardly decreases.

[Example] An example of the present invention will be described below in detail based on the drawings.

In Figures 1 and 2, 1 is a cylinder;
Plug heads 9A and 9B, which have passages 8A and 8B extending through them for supplying and discharging pressure fluids such as air and hydraulic pressure, are fitted to both ends of the cylinder 1 in an airtight or watertight manner. A piston 2 is slidably fitted into the cylinder 1. Pressure fluid is alternately supplied to cylinder chambers 1A and 1B formed on both sides of the piston 2 through valves (not shown) and the flow paths 8A and 8B, whereby the piston 2 It is driven reciprocally in the cylinder axis direction.

Reference numeral 3 denotes a driven body, which is supported above the cylinder 1 so as to be able to reciprocate in parallel or substantially parallel to the cylinder axis along a cylindrical guide rail 10 installed between the plug heads 9A and 9B. There is. For example, one end of the link mechanism for opening/closing the automatic opening/closing door described above, a welding device, etc. are attached to the driven body 3.

The cylindrical guide rail 10 has a groove that opens upward. As shown in FIG. 2, both sides of the opening of the guide rail 10 are prevented from expanding by band-like members 11, 11 for preventing expansion. The band members 11, 11 are bolted to a pedestal 12 that holds the cylinder 1.

In FIG. 1, reference numerals 5 and 5 indicate curved paths, which are formed across both side surfaces of the piston 2 in the movement direction and both side surfaces of the driven body 3. A large number of spheres 6 are lined up with almost no rolling. This sphere 6
is for transmitting the moving force of the piston 2 to the driven body 3, and the moving force transmitting mechanism 4 is constituted by the sphere 6 and the bending paths 5, 5. As the sphere 6, a molded nylon ball or a steel ball, which has excellent hardness and wear resistance and has a small coefficient of wear, can be used.

The bending paths 5, 5 are U-shaped through paths 5A,
5B, upper straight routes 5D, 5D, and lower straight routes 5C, 5C. The U-shaped through passage 5
A and 5B are formed in the plug heads 9A and 9B. The upper straight paths 5D, 5D are located outside the cylinder 1 and are connected to the cylindrical guide rail 1.
It is formed by 0. The lower straight path 5
As shown in FIG. 2, C and 5C are formed by three guide rods 7 arranged at equal angular pitches (120 degrees at the center angle) within the cylinder 1. Therefore, the lower straight paths 5C, 5C are located within the cylinder 1, communicate with the cylinder chambers 1A, 1B shown in FIG. 1, and form part of the cylinder chambers 1A, 1B. The guide rod 7 is connected to the plug heads 9A, 9.
It is installed parallel to the cylinder axis line between B and B.

Reference numerals 13 and 13 designate elastic seal members for airtightness or oiltightness;
It is fitted in a cylindrical shape at the starting end portions of the through passages 5A and 5B extending through the holes A and 9B. The spherical body 6 is in sliding contact with this sealing member 13 . Reference numeral 14 in FIG. 2 is a band-shaped seal provided along the upward opening of the cylindrical guide rail 10.

The operation of the actuator configured as above will be explained.

By switching valves (not shown), the cylinder chambers 1A on both sides of the piston 2 in FIG.
Alternatively, pressure fluid such as air is alternately supplied to 1B. This supply of pressure fluid causes the piston 2 to reciprocate in the direction of the arrow X-X', and the driving force is transmitted to the driven body 3 via the sphere 6, which moves the driven body 3 in the direction of the arrow Y-Y'. Move back and forth. This causes a movable member such as a door to reciprocate between two positions.

Next, another embodiment will be described.

[] The embodiment shown in FIG. 3 is an embodiment in which a guide 15 for regulating the moving path of the driven body 3 or a movable member that moves together with the driven body 3 is provided. In this case, there is an advantage that the left and right spheres 6 can be arranged closely and continuously, and the position of the stroke range of the driven body 3 can be easily adjusted.

[Effects of the Invention] As can be understood from the above description, according to the present invention, unlike a wire or the like, the sphere 6 has a large spring constant, so it is difficult to deform over time even if a moving force is applied repeatedly. . Further, since the thermoelastic coefficient of the sphere 6 is smaller than that of a wire or the like, expansion etc. due to temperature changes can be suppressed. In this way, the spherical body 6 is less likely to deform over time and is also less likely to expand due to temperature changes, so that the motion performance of the driven body 3 can be maintained stably over a long period of time.

In addition, since the straight path 5C in the cylinder 1 of the bent path 5 constitutes the cylinder chambers 1A and 1B, pressure fluid is also introduced into the straight path 5C, and the sphere 6 makes point contact with the piston 2. , the pressurizing force of the pressurized fluid is applied to almost all sides of the piston 2. In other words, even if the sphere 6, which is a moving force transmission medium, is in pressure contact with the piston 2, the pressure-receiving area of the piston 2 hardly decreases. Therefore, since the cross-sectional area of the piston 2 can be reduced, the overall size of the device is not increased.

[Brief explanation of drawings]

Fig. 1 is a longitudinal cross-sectional side view of one embodiment, and Fig. 2 is a longitudinal side view of one embodiment.
FIG. 3 is a longitudinal sectional side view of main parts showing another embodiment, and FIG. 4 is a schematic longitudinal sectional side view showing a conventional example. 1...Cylinder, 1A, 1B...Cylinder chamber,
2... Piston, 3... Driven body, 4... Moving force transmission mechanism, 5... Bent path, 5C... Straight path, 6
... Sphere, 7... Guide rod.

Claims (1)

[Scope of Claims] 1. A cylinder 1, a piston 2 slidably fitted into the cylinder 1, and a piston 2 formed on both sides of the piston 2 to which pressure fluid is supplied. A pair of cylinder chambers 1A and 1B that are reciprocated, a driven body 3 that is movably provided outside the cylinder 1, and a moving force transmission mechanism 4 that transmits the reciprocating driving force of the piston 2 to the driven body 3. A reciprocating actuator using a fluid pressure cylinder, comprising: a bending path 5 formed between the driven body 3 and the piston 2; The moving force transmission mechanism 4 is constituted by the sphere 6 having a diameter of 1 and a cylindrical seal member 1 with which the sphere 6 slides.
3 is a reciprocating actuator using a fluid pressure cylinder. 2. The straight line path 5C located inside the cylinder 1 among the bending paths 5 is formed by three or more guide rods 7 extending through the piston 2 and extending parallel to the cylinder axis. The reciprocating actuator using a fluid pressure cylinder according to item 1. 3. The reciprocating actuator using a fluid pressure cylinder according to claim 1, wherein the sphere 6 is a steel ball. 4. The reciprocating actuator using a fluid pressure cylinder according to claim 1, wherein the sphere 6 is a molded nylon ball having excellent hardness, wear resistance, and a small coefficient of friction.