JPH0228252Y2 - - Google Patents

Description

[Detailed explanation of the idea]

(Field of Industrial Application) The present invention relates to an improvement of a hydraulic constant velocity cylinder in which each piston rod of a piston cylinder formed in multiple stages is expanded and contracted at a constant velocity. Equipment that requires (e.g. elevators, machine tools,
It is mainly used as a drive source for civil engineering machinery, etc.). (Prior Art) Conventionally, as a means to achieve uniform expansion and contraction of a multi-stage hydraulic cylinder, there have been two methods: (a) making the pressure-receiving areas of the pistons of each stage equal; Various methods have been developed, including (b) a method of pumping the required amount of hydraulic oil to each stage of the cylinder separately, and (c) a method of pre-filling each stage of the cylinder with the necessary hydraulic oil. ing. However, in the method (a) of making the pressure receiving area of each stage equal, there is a problem in that the outer diameter of the cylinder becomes significantly larger than the stroke length of the piston, resulting in an increase in the size of the piston cylinder. In addition, in the case of the method described in (b) above, in which the required amount of hydraulic oil is separately pumped to each stage of the cylinder, a specially constructed hydraulic oil feeding device with a complicated structure must be installed outside the cylinder device. There is a drawback. Furthermore, in the method (c) of pre-filling hydraulic oil into each stage of the cylinder, it is necessary to constantly check for leakage of the sealed hydraulic oil, which requires maintenance and requires a large amount of weight. The problem is that it is not suitable for launching. (Problems to be Solved by the Invention) The present invention solves the above-mentioned problems in conventional multi-stage hydraulic constant velocity cylinders of this type, namely (a) unavoidable enlargement of the cylinder device, and (b) A separate hydraulic oil feeding device with a complicated structure is required, or
(c) It aims to solve the problem of cylinder maintenance being too time-consuming, etc., and does not require special accessory equipment or increase the size of the cylinder device, and is simple and reliable. The present invention provides a multi-stage hydraulic constant-velocity cylinder that enables constant-velocity piston expansion and contraction and launches of large weights. (Means for Solving the Problems) The present invention includes a hollow guide body 1b disposed at the center of the interior of a cylindrical outer cylinder 1a, and a cylindrical cylinder wall 1c concentrically disposed outside the hollow guide body 1b. Said outer cylinder 1
a first-stage cylinder 1 with a first-stage cylinder chamber Q between the cylinder wall 1c and the outer cylinder 2c forming a first-stage piston portion 2a and a first-stage piston rod 2b;
and an inner cylinder 2d forming a second-stage cylinder chamber R disposed concentrically inward thereof into a double-cylindrical shape, and an outer cylinder 2c is introduced into the cylinder chamber Q of the first-stage cylinder 1. , a first stage piston 2 which is slidably inserted by inserting a hollow guide body 1b into the cylindrical cylinder wall 1c; and an outer part forming a second stage piston part 3a and a second stage piston rod 3b. Tube 3c
The inner cylinder 3d of the first stage piston, which forms the second stage cylinder chamber R, is formed into a double cylindrical shape with an inner cylinder 3d concentrically disposed inside thereof and forming the third stage cylinder chamber S. A second stage piston 3 is slidably inserted into the cylinder 2d; A third stage piston 4 is slidably inserted between an outer cylinder 3d and an inner cylinder 3d of the stage piston; the front opening of the cylindrical third stage piston rod 4b is closed;
A stopper 5 that forms an oil chamber I in the inner space of the front chamber Qa of the first stage cylinder chamber Q, and the front chamber Ra and rear chamber of the second stage cylinder chamber R during the extrusion operation of each piston.
Rb, a flow oil port 6 and an oil passage 7 that respectively supply hydraulic oil to the oil chamber I inside the third stage piston rod 4b; the rear chamber Qb of the first stage cylinder chamber Q and the third It consists of an oil flow port 8 and an oil passage 9 for discharging hydraulic oil from the rear chamber Sb of the stage cylinder chamber S, and a pressure receiving area A of the first stage piston part 2a;
Outer diameter cross-sectional area of cylindrical second stage piston rod 3b
B′, the pressure receiving area C of the third stage piston portion 4a,
The basic structure of the invention is to maintain the relationship A≈B'≈C+D between the inner diameter cross-sectional area D of the cylindrical third stage piston rod 4b. (Function) When each piston rod 2b, 3b, 4b is pushed out, hydraulic oil is supplied from the oil flow ports 6a, 6b directly or via a differential pressure valve. The hydraulic oil from the flow oil port 6a is supplied to the first stage cylinder front chamber Qa, the second stage cylinder front chamber Ra, the third stage cylinder front chamber Sa and the oil chamber I through the oil passages 7a to 7e, and The hydraulic oil from the oil port 6b flows through the oil path 7.
It is supplied into the second stage cylinder rear chamber Rb through f. Assuming that the pressure-receiving area A of the first-stage piston portion 2a, the outer diameter cross-sectional area B' of the second-stage piston rod 3b, the pressure-receiving area C of the third-stage piston portion 4a, and the inner diameter cross-sectional area D of the third-stage piston rod 4b, each In between,
The relationship A≒B′≒C+D is maintained. As a result, the total pushing force acting on the first stage piston 2 is A-B'=O, the total pushing force acting on the second stage piston 3 is B'-(C+D)=O, and the total pushing force acting on the third stage piston 4. The total pushing force is C+D, and the third stage piston 4 (namely, the stopper 5) is pushed forward by a force of (C+D)×P (P is the oil pressure of the hydraulic oil). That is, the third stage piston 4 extends leftward at a constant speed, and being pulled by this, the second stage piston rod 3b and the first stage piston rod 2b each extend leftward at a constant speed. In addition, the hydraulic oil is discharged through the oil flow port 8a,
It is carried out from 8b. On the other hand, each extended piston rod 2b, 3
b, 4b, when returning oil flow ports 8a, 8b, 6
Hydraulic oil is sent in from b, and is discharged from oil flow port 6a. (Example) Hereinafter, an example of the present invention will be described based on FIGS. 1 to 3. FIG. 1 is a vertical sectional view of the upper half of the hydraulic transmission cylinder according to the present invention, and in the figure, 1 indicates the first
Stage cylinder, 2 is a first stage piston, 3 is a second stage piston, 4 is a third stage piston, 5 is a stopper, 6 is an oil flow port, 7 is an oil passage that communicates with the flow oil port 6, 8 is a The oil outlet 9 is an oil passage communicating with the oil outlet 8. The first stage cylinder 1 includes a cylindrical outer cylinder 1a with one side open, a hollow guide body 1b provided at its axis, and a space between the hollow guide body 1b and the inner wall surface of the outer cylinder 1a. and a cylindrical cylinder wall 1c provided concentrically, and the space between the outer cylinder 1a and the cylinder wall 1c is a first stage cylinder chamber Q (cylinder front chamber Qa, cylinder rear chamber Qb). There is. The first stage piston 2 is formed into a double cylindrical shape that can be inserted into the first stage cylinder 1, and includes a first stage piston portion 2a and a first stage piston rod 2.
It is composed of an outer cylinder 2c for forming a cylinder b, and an inner cylinder 2d for forming a second stage cylinder chamber R disposed concentrically inside the outer cylinder 2c. That is, the first stage piston 2 has its piston portion 2
A into the first stage cylinder 1 by inserting the outer cylinder 2c forming the cylinder a into the first stage cylinder chamber Q and inserting the inner cylinder 2d into the cylinder wall 1c through the hollow guide body 1b. They are slidably inserted and kept oil-tight by gaskets 10a, 10b, 10c and gaskets 11a, 11b, 11c, respectively. The inner cylinder 2d of the first stage piston 2 forms a cylinder of a second stage piston 3, which will be described later, and the second stage piston 3 is slidably inserted therein. Further, the piston rod portion 2b of the first stage piston 2 is supported in an airtight manner by passing through a rod cover 12 screwed onto the open end of the first stage cylinder 1. The second stage piston 3 is formed into a double cylinder shape from an outer cylinder 3c and an inner cylinder 3d, with the base ends of the inner and outer cylinders serving as the second stage piston part 3a, and the outer cylinder 3c serving as the second stage piston part 3a. A piston rod 3b is formed respectively. Further, a third stage cylinder chamber S is formed between the cylindrical second piston rod 3b (i.e., outer cylinder 3c) and the inner cylinder 3d, and a third stage piston 4, which will be described later, is inserted therein. . Furthermore, inside the inner cylinder 3d is an oil chamber I, which will be described later.
It's getting old. The second stage piston 3 is inserted into the inner cylinder 2a of the first stage piston 2, that is, the second stage cylinder chamber R (cylinder front chamber Ra, cylinder rear chamber Rb) with a packing 14.
The piston rod 3b is slidably inserted in an oil-tight manner via the first stage piston rod 2a and 14b. In addition, the piston rod 3 of the second stage piston 3
As mentioned above, b forms the cylinder of the third stage piston 4, and the third stage piston 4, which will be described later, is slidably inserted inside the cylinder (cylinder chamber S). The third stage piston 4 includes a cylindrical third stage piston rod 4b and a disc-shaped third stage piston portion 4.
a, and the second stage piston 3
It is slidably inserted into the third stage cylinder chamber S (cylinder front chamber Sa, cylinder rear chamber Sb) formed between the outer cylinder 3b and the inner cylinder 3d via gaskets 16a and 16b. Also, the piston rod 4b of the third stage piston 4
is slidably supported by a rod cover 16 screwed onto the opening on the distal end side of the second stage piston 2. Further, a spherical stopper 5 is screwed onto the opening at the tip end of the cylindrical piston rod 4b of the third stage piston 4, thereby sealing the opening at the tip of the third stage piston rod 4b. An oil chamber I is formed. In addition, in FIG. 1, 18 is a head having a spherical seat crowned by the plug body 5, and 19a, 19b
is Patsukin, 6a, 6b, 8a, 8b oil outlet, 7
A to 7f and 9a are oil passages, and 20a to 20h are oil pipes. Furthermore, in FIG. 1, 21 is a differential pressure valve, which is indicated by a simple symbol according to JISB-0125 in FIG. That is, the differential pressure valve 21 has a valve box 21a having three ports X, Y, and Z, as shown in FIG. 2 (when the piston moves forward under pressure) and FIG. 3 (when the piston moves back and forth). It is formed from a check valve body 21b. Now, assuming that the pressure on the port X side is Px, the pressure on the port Y side is Py, and the pressure on the port Z side is Pz, if Py<Px, the check valve body 21b
The state will be as shown in Figure 2, and port X and port Z
is in circulation. As a result, the hydraulic oil is supplied to both the flow oil port 6a and the flow oil port 6 in FIG. 1, and each piston 2, 3, 4 operates in the projecting direction. Moreover, contrary to the above, when Py>Px, the check valve body 21b is in a state as shown in FIG. 3, and ports Y and Z are in communication. As a result, the hydraulic oil is supplied to the oil flow ports 8a, 8b, and 6b, and the protruding pistons 2, 3, and 4 return and retreat. Next, the operation of the hydraulic constant velocity cylinder according to the present invention will be explained. Referring to FIG. 1, when the pistons 2, 3, and 4 are moved to protrude, a hydraulic pump (not shown) is used.
Hydraulic oil is supplied from there through the oil feed pipe 20a. In this case, the differential pressure valve 21 is in the state shown in FIG. 2 (Py<Px), and the hydraulic oil is flowing through the oil flow port 6a.
is supplied from the oil outlet 6b, and the oil is supplied from the oil outlet 8a.
and are discharged from the flow oil port 8b, respectively. Pressure oil F entering from the oil flow port 6a passes through the oil passage 7a toward the first stage piston 2 and the hollow part (oil passage) of the hollow guide 1b, and then flows into the oil passage 7 toward the second stage piston 3.
It branches into b. The former enters the front chamber Qa (its area, that is, the pressure receiving area is A) of the first stage cylinder wall Q, which is surrounded by the outer peripheral wall of the first stage cylinder 1 and the outer peripheral wall of the cylinder wall 1c. Press the first stage piston portion 2a. The latter enters the oil chamber I through the oil passage 7c, presses the third stage piston rod 4b through the plug body 5 (the pressure receiving area is D), and also passes through the oil passage 7d to the front of the second stage cylinder chamber. It enters the chamber Ra, presses the piston part 3b (the pressure receiving area is B) of the second stage piston 3, and further enters the front chamber Sa of the third stage cylinder chamber S through the oil passage 7e, and the third stage piston 4 (the pressure receiving area is C) is pressed. On the other hand, the hydraulic oil that has flowed from the oil inlet 6b through the differential pressure valve 21 flows into the rear chamber Rb of the second stage cylinder chamber R through the oil passage 7f, and presses the second stage piston 3 in the opposite direction (backward direction). Press. Now, the outer diameter cross-sectional area of the second stage piston rod 3b
B', pressure receiving area E of second stage cylinder rear chamber Rb = B-
B', pressure receiving area of oil chamber I (third stage piston part 4b
If D is the internal diameter cross-sectional area of Become.

[Table] Therefore, now the pressure receiving area A of the first stage piston 2,
A between the outer diameter B' of the second-stage piston rod 3b, the pressure-receiving area C of the third-stage piston 4, and the pressure-receiving area D of the third-stage piston rod 4b (that is, the pressure-receiving area D of the ejection force applied via the stopper 5). =B'=(C+D)...If the following relationship is established, the pushing force acting on the first stage piston 2 is A=B'=O, and the pushing force acting on the second stage piston 3 is B'-(C+D) =O, and only the third stage piston 4 moves forward with a constant pushing force D+C. That is, only the third stage piston 4 moves forward with a constant pushing force, and the first stage piston 2 and the second stage piston 3
moves forward while being pulled by the third-stage piston 4 (the pushing force is zero), thereby achieving so-called constant-velocity three-stage expansion. At this time, the hydraulic oil in the rear chamber Qb of the first stage cylinder chamber Q is transferred from the oil flow port 8a to the rear chamber of the third cylinder chamber.
The Sb hydraulic oil is discharged from the flow path 9a and the flow oil port 8b, respectively. Further, the space J and the space K are communicated with each other by the protrusion of the first stage piston 2, and internal air is circulated and moved. Furthermore, each extended piston rod 2, 3,
4, transfer the hydraulic oil to the oil feed pipe 20 in Figure 1.
The hydraulic oil is sent from the h side to the oil outlet 6b through the oil outlet 8b, 8a and the differential pressure valve 21, and the hydraulic oil is discharged from the oil outlet 6a to the tank side. (Specific Example) In this embodiment, the first stage piston portion 2
The outer diameter of a is 360mm and the inner diameter is 300mmφ, the outer diameter of the second stage piston part 3a is 224mm and the outer diameter of its piston rod 3b is 199mm, the outer diameter of the third stage piston part 4a is 170mm, the inner diameter is 63mm and its piston rod. The outer diameter of 4b was selected to be 150 mm, and the inner diameter was selected to be 120 mm. As a result, the pressure receiving area A of the first stage piston 2, the pressure receiving area B, B' of the second stage piston 3, the pressure receiving area C of the third stage piston 4, and the pressure receiving area C of the third stage piston rod 4 are obtained.
The pressure receiving area of b (pressure receiving area of the stopper 5) D is as follows: A = π/4 (36 ² - 30 ² ) = 310 cm ² , B = π/4 x 22.4 ² = 394 cm ² , B' = π/4 x 19.9 ² = 310 cm ² C = π/4 (17 ² -6.3 ² ) = 197 cm ² D = π/4 x 12 ² = 113 cm ² That is, the above relationship is established so that A≒B'≒C+D=310 cm ² Each dimension is selected, and as a result, from Table 1 above, the total pushing force of the first stage piston 2 is A-B'=O, and the total pushing force of the second stage piston 3 is B'-(C+D). = O, the total pushing force of the third stage piston 4 is D + C = 310 cm ² , 310 cm ² × oil pressure (Kg/
cm ² ) acts on the third stage piston rod 4b. As a result, the third stage piston rod 4b extends leftward at a constant speed, and the first stage piston rod 2a and the second stage piston rod 3b are pulled by this and extend at the same speed as the third stage piston rod 4b. (Effect of the invention) In the present invention, as mentioned above, the first stage cylinder 1,
First stage piston 2 with second stage cylinder chamber R
The second stage piston 3 provided with the third stage cylinder chamber S and the third stage piston 4 forming the oil chamber I are combined in a multi-stage configuration, respectively, and the pressure receiving areas A, C, D and the outer diameter cross-sectional area B' of the second stage piston 3b are configured to have a certain condition, so when each piston is extended (extruded), the third
A constant pressing force (pressure receiving area (C
+D) x oil pressure) acts, and the second stage piston 3 and the first stage piston 2 are pulled by the third stage piston 4 and expand at a constant speed, achieving extremely stable constant speed expansion. be done. In addition, the desired extrusion force can be obtained even with a cylinder device with a relatively small diameter, and the piston stroke can be easily lengthened, making it possible to create a compact multi-stage cylinder with a long piston stroke compared to the outer diameter of the cylinder. can be formed. Furthermore, when the hydraulic oil is supplied and discharged through the differential pressure valve 21, the extrusion and retraction control of the multistage piston rod can be performed simply by switching the supply direction of the hydraulic oil, which is extremely convenient in practice. As mentioned above, the present invention has excellent practical effects.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of the upper half of the hydraulic constant velocity cylinder according to the present invention. 2 and 3 are explanatory diagrams of the operation of a differential pressure valve suitable for the operation of the present invention. 1...First stage cylinder, 1a...Cylindrical outer cylinder,
1b...Hollow guide body, 1c...Tylindrical cylinder wall, Q...1st stage cylinder chamber, 2...1st stage piston, 2a...1st stage piston part, 2b...1st stage
Stage piston rod, 2c...outer cylinder, 2d...inner cylinder, A...pressure receiving area of first stage piston part, R...
2nd stage cylinder chamber, Ra... Cylinder front chamber, Rb...
...Cylinder rear chamber, 3...Second stage piston, 3a...
...Second stage piston part, 3b...Second stage piston rod, 3c...Outer cylinder, 3d...Inner cylinder, B...Second stage
Pressure-receiving area of the stage piston part, B'...External cross-sectional area of the second stage piston rod, S...Third stage cylinder chamber, Sa...Cylinder front chamber, Sb...Cylinder rear chamber,
4...3rd stage piston, 4a...3rd stage piston part, 4b...3rd stage piston rod, C...3rd stage piston rod
Pressure-receiving area of stage piston part, D...3rd stage piston rod internal cross-sectional area, I...oil chamber, 5...stopper, 6...
...Oil port, 7...Oil channel, 8...Oil port, 9...Oil channel, 12...Rod cover, 13...Rod cover, 15...Rod cover, 17...Rod cover, 18...Head, 20 ...Oil pipe, 21...
Differential pressure valve.

Claims (1)

[Scope of utility model registration request] A hollow guide body 1b is provided in the center of the cylindrical outer cylinder 1a.
In addition, a cylindrical cylinder wall 1c is arranged concentrically outside the hollow guide body 1b, and a first stage cylinder chamber Q is formed between the outer cylinder 1a and the cylinder wall 1c. It is formed into a double cylinder shape by an outer cylinder 2c forming the first stage piston part 2a and the first stage piston rod 2b, and an inner cylinder 2d forming the second stage cylinder chamber R disposed concentrically inside the outer cylinder 2c. , outer cylinder 2
c into the cylinder chamber Q of the first stage cylinder 1,
A first stage piston 2 is slidably inserted into the inner cylinder 2d by inserting the hollow guide body 1b into the cylindrical cylinder wall 1c; an outer cylinder forming the second stage piston part 3a and the second stage piston rod 3b. 3c and an inner cylinder 3d concentrically disposed inside the inner cylinder 3d forming a third stage cylinder chamber S. The second stage piston 3 is slidably inserted into the inner cylinder 2d.
and; is formed into a cylindrical shape from the third stage piston part 4a and the third stage piston rod 4b, and is slidable between the outer cylinder 3b and the inner cylinder 3d of the second stage piston forming the third stage cylinder chamber S. Inserted third stage piston 4
a stopper 5 that closes the front opening of the cylindrical third stage piston rod 4b and forms an oil chamber I in the inner space of the piston rod 4b; and a stopper 5 that closes the front opening of the cylindrical third stage piston rod 4b; antechamber Qa,
The front chamber Ra and rear chamber Rb of the second stage cylinder chamber R, the third
A flow oil port 6 and an oil passage 7 that supply hydraulic oil to the oil chamber I inside the stage piston rod 4b and the front chamber Sa of the third cylinder chamber S, respectively; and after the first stage cylinder chamber Q during each piston pushing operation. It consists of an oil flow port 8 and an oil passage 9 for discharging hydraulic oil from the rear chamber 5b of the chamber Qb and the third stage cylinder chamber S. Between the outer diameter cross-sectional area B' of the piston rod 3b, the pressure receiving area C of the third stage piston portion 4a, and the inner diameter cross-sectional area D of the cylindrical third stage piston rod 4b, A≒B'≒C+.
A hydraulic constant velocity cylinder characterized by maintaining the relationship D.