JP3728526B2 - Air vent structure in multi-stage hydraulic jack - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an air vent structure in a multistage hydraulic jack suitable for raising and lowering a home (home) elevator or the like.
[0002]
[Prior art]
There are some home elevators installed in the homes of elderly people and people with disabilities who are struggling to move up and down stairs. Such a home elevator is required to start and stop without shock and to smoothly move up and down. There are various drive structures for this home elevator. One of them is a multistage hydraulic jack in which pistons are stacked in multiple stages, as previously proposed by the present applicant as Japanese Patent Laid-Open No. 10-141323. This multi-stage hydraulic jack communicates the back pressure chamber of the lower piston and the positive pressure chamber of the upper piston, shortens each piston, and fills each back pressure chamber with pressure oil. When the pressure oil is supplied to the positive pressure chamber of the piston and raised, the volume of the back pressure chamber decreases, so that the piston is raised by flowing it into the positive pressure chamber of the upper piston. It consists of each piston.
[0003]
On the other hand, when lowering the multistage hydraulic jack, the pressure in the positive pressure chamber of the lowest piston is released. Then, due to the weight of each piston, the pressure oil in the positive pressure chamber of the upper piston flows into the back pressure chamber of the lower piston and descends. Therefore, the pressure oil filled in the back pressure chamber of each piston except the positive pressure chamber of the lowest piston will reciprocate between the positive pressure chambers of the upper piston, and at this point, The volume of the back pressure chamber of the lower piston and the positive pressure chamber of the upper piston are set equal.
[0004]
According to this, when pressurized oil is supplied to the positive pressure chamber of the lowest piston at a constant rate per hour, each piston moves at the same time, and the highest piston moves at a constant speed. At this time, if the extension amounts of the pistons of the respective stages are made the same, the respective end points are at the same timing, so that a smooth movement without shock can be ensured during the extension. In addition, since this piston can be stacked in multiple stages, it is possible to obtain a large extension amount compared to the contraction length. Therefore, it can be said that this multistage hydraulic jack is preferable as a driving source of the home elevator.
[0005]
In this case, when the back pressure chamber of the lower piston is filled with pressure oil, no air should remain in it. If air remains, pulsation occurs when each piston expands and contracts, and the movement of the elevator box fluctuates, making the ride uncomfortable and giving the passenger anxiety. In addition, the air may be compressed during extension to lower the elevator box, resulting in a step difference from the floor surface. For this reason, an air vent structure is provided, but as this air vent structure, the upper end ring attached to the upper end of the rod cylinder of the lower piston that slidably holds the rod cylinder of the upper piston is plugged with a plug. This is dealt with by forming an air vent passage communicating with the inner and outer peripheries. That is, the plug is removed when the back pressure chamber of the lower piston is filled with pressure oil, and the plug is closed when the pressure oil is completely filled and the pressure oil overflows from the air vent passage.
[0006]
[Problems to be solved by the invention]
According to this, the air discharged from the air vent passage is limited to the air that has passed through a part of the upper ring of the lower piston and entered the rod cylinder of the upper piston facing the air vent passage. Therefore, the pressure required for this penetration may not be sufficient. Also, when the piston head of the upper piston comes into contact with the upper end ring of the lower piston and becomes the upward stroke end, pressure oil remains in the back pressure chamber of the lower piston. In such a case, the air may remain compressed and pass through a part of the upper end ring and may not enter the rod cylinder of the upper piston. The present invention solves such a problem, and allows air to escape sufficiently (can be discharged).
[0007]
[Means for Solving the Problems]
Under the above-mentioned problems, the present invention inserts the upper piston so as to be movable up and down by the rod cylinder of the lower piston and the upper end ring attached to the upper end of the lower piston, and The back pressure chamber communicates with the positive pressure chamber of the upper piston to shorten each piston and fill each back pressure chamber with pressure oil, and the upper ring is filled with pressure oil to the back pressure chamber of the lower piston. In an air vent structure in a multistage hydraulic jack that forms an air vent passage for venting air accumulated in the back pressure chamber during filling, the air vent passage is covered with a plug so that the inner periphery and outer periphery of the upper end ring communicate with each other. It consists of a transverse passage and a longitudinal passage that communicates with the back pressure chamber of the lower piston and merges with the transverse passage, while maintaining a gap between the piston head of the upper piston and the rod cylinder of the lower piston. Kamenobu That a connection is provided, wherein the upper end of the connection portion other to that upward movement in contact with the upper end ring of the lower piston is restricted, which is formed across the longitudinal passage and the connecting portion and the gap The air vent structure in the multistage hydraulic jack is provided.
[0008]
The present invention takes the above-described means. That is, the air vent passage is composed of a lateral passage that communicates the inner periphery and the outer periphery of the upper ring, and a longitudinal passage that communicates with the back pressure chamber of the lower piston and joins the lateral passage. Therefore, not only the air that has passed through a part of the upper end ring and entered the rod cylinder of the upper piston facing the air vent passage, but also the air accumulated in the back pressure chamber of the piston described above. Since it can be extracted together, the air remaining in the back pressure chamber can be reduced as much as possible.
[0009]
In addition, the piston head top position of the piston, the connecting portion of the upper extension is provided by maintaining a gap between the rod tube of the lower piston, the upper end of the connection portion to the upper end ring of the lower piston are those upward movement is restricted by contact with, as long as the longitudinal channel is formed astride the connecting portion and the gap, to the air vent in the back pressure chamber become more fully, according to claim 2 If the vertical passage joins the lateral passage on the inner peripheral side of the plug, the inflow of air when the plug is inserted can be prevented.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a partially sectional side view of a contracted state of a multistage hydraulic jack showing an example of the present invention, FIG. 2 is a partially sectional side view of an expanded state, and FIG. 3 is a partially sectional view of a lower portion of the contracted state. In this multi-stage hydraulic jack (hereinafter referred to as a hydraulic jack), a first piston 2 is inserted in an upright cylinder 1 so as to be movable up and down, and a second piston 3 is inserted in the first piston 2 in the same manner. The third piston 4 is similarly inserted into the piston 3. It should be noted that the number of piston stages is not limited to this, and some pistons are more or less.
[0011]
The cylinder 1 has a cylinder cylinder 7 connected to a lower block 6 provided with a pressure oil port 5 and extends upward, and an end ring 8 is attached to the upper end. The first piston 2 extends from a piston head 9 to which a rod cylinder 10 is connected. In this case, the piston head 9 is slidably mounted in the cylinder cylinder 7, and the rod cylinder 10 has an upper end. Is slidably mounted in a state protruding upward on the end ring 8, and the end ring 11 is attached to the uppermost end. Hereinafter, the second piston 3 and the third piston 4 are configured in the same manner. The second piston 3 includes a piston head 12, a rod cylinder 13, and an end ring 14, and the third piston 4 includes a piston head 15. The rod cylinder 16 is provided (the end cylinder is not provided on the rod cylinder 16 of the uppermost third piston 4).
[0012]
Therefore, the first piston 2 has a positive pressure chamber 17 and a back pressure chamber 18 with the piston head 9 as a boundary. Similarly, the second piston 3 and the third piston 4 are respectively connected to the respective piston heads 12. , 15 have positive pressure chambers 19 and 21 and back pressure chambers 20 and 22. In this case, the back pressure chamber 18 of the first piston 2 and the positive pressure chamber 19 of the second piston 3 communicate with each other. In this example, there are several locations on the wall surface of the rod cylinder 10 of the first piston 2. An outflow / inflow hole 23 is formed.
[0013]
The outflow / inflow hole 23 has a shape in which a diameter detail 23a is formed at the center, and a gradually thickened portion 23b whose diameter gradually increases from the diameter detail 23a to the inner and outer surfaces. This is to prevent the generation of vortices and the generation of sound and pulsation when pressure oil flows in and out. In this regard, it is preferable that 2 to 8 inflow / outflow holes 23 are formed in the rod cylinder 10 at equal intervals. A similar configuration is also seen in the second piston 3, and an outflow / inflow hole 24 is formed in the rod cylinder 13 of the second piston 3 (the diameter detail 24a and the gradually thickened portion 24b are the same). Further, the same applies to the third piston 4, but in this example, an outflow / inflow passage 25 communicating the positive pressure chamber 21 and the back pressure chamber 22 is formed from the piston head 15 to the rod cylinder 16. .
[0014]
Furthermore, in the hydraulic jack of the present invention, when the pressure oil in the positive pressure chamber 17 of the first piston 2 reaches a constant pressure across the positive pressure chamber 17 of the first piston 2 and the positive pressure chamber 19 of the second piston 3. A check valve 26 is provided to flow the pressure oil into the positive pressure chamber 19 of the second piston 3 and prevent backflow. The check valve 26 of this example is provided in the piston head 9 of the first piston 2, and a stepped through hole 27 having a large diameter at the upper part is formed at the center of the piston head 9. A spool 28 having a tapered portion 28a with a lower surface tapered and bulging to the outer periphery and having a flat upper surface is formed on the small portion so as to be movable up and down.
[0015]
In this case, a narrow neck portion 28b is formed in the lower portion of the taper portion 28, and a branch passage 28c perpendicular to the axial center opening in a balanced manner on the outer periphery of the neck portion 28b is formed in the spool 28. Then, an axial core direction 28 d that opens at the lower end is formed at the center of the spool 28, and the branch path 28 c and the main path 28 d are communicated to form an outflow path 29. On the other hand, a space 30 is secured above the spool 28, and the space 30 is covered with a cap 31 fitted to the large diameter portion of the through hole 27. Outflow holes 32 penetrating vertically are formed in the cap 31 at appropriate intervals on the circumference, and the cap 31 and the tapered portion 28 a are stretched by a spring 33. In addition, the convex part 28e is also formed in the center of the upper surface of the taper part 28a (the flat part remains on the outer peripheral side of the convex part 28e), and this convex part 28e was formed in the lower surface of the cap 31. A part of it enters the recess 31a. In this case, the spring 33 is stretched between the outer periphery of the convex portion 28e and the inner periphery of the concave portion 31a.
[0016]
When pressure oil flows from the positive pressure chamber 17 of the first piston 2 into the positive pressure chamber 19 of the second piston 2, the spool 28 moves upward. At this time, the convex surface of the taper portion 28a is formed on the lower surface of the cap 31. A stopper surface 31b that restricts further upward movement by hitting a flat portion on the outer peripheral side of the portion 28e is formed. Further, at this time, the convex portion 28e does not rise to the full extent of the concave portion 31a of the cap 31, and the spring 33 is not shortened to the full extent. In addition, the spool 28 of this example moves up and down in the seat 34 fitted to the piston head 8, and the cap 31 is held by a stop ring 35 by pressing the seat 34 from above. The above check valve 26 is also incorporated in the piston head 12 of the second piston 3, and in this example, the structure of these check valves 26 is common.
[0017]
As described above, the pistons 2 to 4 are sequentially assembled (installed with the end rings 8, 11 and 14 removed), and each is shortened. In this example, in this state, the pistons 2 to 4 are in contact with the lower pistons 2 to 4 and do not lower any further. Next, the uppermost piston 4 is pressed from above so as not to rise, and pressure oil is supplied from the pressure oil port 5 of the cylinder 1 to the positive pressure chamber 17 of the first piston 2. Then, the pressure oil pushes up the spool 28 of the check valve 26 of the first piston 2, passes through the upper space 30 and the outlet hole 32 of the cap 31 from the outlet passage 29 formed in the spool 28, and the positive pressure chamber 19 of the second piston 3. Then, the back pressure chamber 18 of the first piston 2 is filled through the outflow / inlet hole 23 formed in the rod cylinder 10 of the first piston 2.
[0018]
When this filling is full, this time, the spool 28 of the check valve 26 of the second piston 3 is pushed up and flows into the positive pressure chamber 19 of the second piston 3, and passes through the outflow / inlet hole 24 formed in the rod cylinder 13. The back pressure chamber 20 of the second piston 2 is filled. Further, when this filling is full, the back pressure chamber 22 is filled through the outflow / inflow passage 25 formed in the third piston. In this way, the back pressure chambers 18, 20, and 22 (of course, the positive pressure chambers 17, 19, and 21) of the pistons 2 to 4 are filled with the pressure oil, thereby completing the initial state. .
[0019]
In order to extend (rise) the hydraulic jack, pressure oil is supplied from the pressure oil port 5 to the positive pressure chamber 17 of the first piston 2. Since the pressure oil supplied to this is applied with back pressure in the positive pressure chamber 19 of the second piston 3, the piston 28 of the first piston 2 is pushed up without operating the spool 28, and the back pressure chamber 18. Reduce the volume of the. Then, the pressure oil in the back pressure chamber 18 flows into the positive pressure chamber 19 of the second piston 3 through the outflow / inflow hole 23, and similarly pushes up the piston head 12 of the second piston 3, and the back pressure of the second piston 3. The volume of the chamber 20 is reduced, and the pressure oil here flows into the positive pressure chamber 21 of the third piston 4 through the outflow / inflow hole 24 and similarly pushes up the piston head 15 of the third piston 4. At this time, the volume of the back pressure chamber 22 of the third piston 4 is reduced, but the pressure oil here flows back to the positive pressure chamber 21 through the inflow / outflow passage 25 connected to the positive pressure chamber 21. Thus, the piston head 15 rises.
[0020]
By the way, in this case, the first piston 2 is when the piston head 9 is fully raised when it abuts against the end ring 8 of the cylinder 1. Similarly, the second piston 3 is the piston head 12. Is when it is fully abutted against the end ring 11 of the first piston 2, and when the piston head 15 of the third piston 4 is abutted against the end ring 14 of the second piston. Is set to be performed at the same time. In this respect, there is no shock at each stage as compared with the pistons 2 to 4 that operate sequentially, and the movement is smooth over the entire stroke.
[0021]
Since the pistons 2 to 4 operate simultaneously, as long as the amount of pressure oil supplied to the positive pressure chamber 17 of the first piston 2 is kept constant per hour, the uppermost third piston 4 is equal You will move fast. In these respects, this hydraulic jack can be said to be preferable as a driving source for this type of elevator. On the other hand, shortening (lowering) can be achieved by releasing the pressure oil pressure in the positive pressure chamber 17 of the first piston 2. That is, the pistons 2 to 4 are contracted by the reverse operation of the pistons 2 due to their own weights (the pistons 2 to 4 are simultaneously in the lowered position as described above).
[0022]
In addition, in this hydraulic jack, the maximum volume of the back pressure chambers 18, 20, and 22 of the lower pistons 2 to 4 and the maximum volume of the positive pressure chambers 17, 19, and 21 of the upper pistons 2 to 4 are set to be the same. Therefore, in principle, it is not necessary to supply and discharge the pressure oil every time the elevator is moved up and down, and it is not necessary to operate the check valve 26 each time. However, in reality, this is difficult. If the positive pressure chambers 17, 19, 21 of the upper pistons 2 to 4 are larger in volume, the pressure oil is replenished during expansion, and if smaller, the end rings 8, Since it leaks through 11, 14, etc., the leaked amount is replenished. Furthermore, since the pressure oil leaks somewhat from the check valve 26 and the end rings 8, 11, and 14 with the operation, it is necessary to compensate for this. These replenishment and compensation are performed by pushing up the check valve 26 and supplying pressure oil to the upper pistons 2 to 4.
[0023]
FIG. 4 is a cross-sectional view when the above hydraulic jack is applied to a home elevator. An elevator passage 36 is formed indoors facing each level, and the hydraulic jack is provided in the passage 36 (37). Is a hydraulic unit that drives the elevator box 38, and an elevator box 38 is attached to the uppermost piston 4. In this case, in order to absorb the height of the hydraulic jack, the hydraulic jack is extended to the back surface of the box 38 and the ceiling portion is connected to the hydraulic jack (for this reason, a mounting structure such as a screw is attached to the tip of the rod cylinder 16. 39). In this case, the stop position is determined so that the floor surface of each level and the floor surface of the box 38 are aligned, but when the hydraulic jack is stopped at the lowest level, as described above, each piston is mechanically contacted. By doing so, there is no drop (step) due to the leak of pressure oil.
[0024]
The present invention relates to an air vent structure provided in upper end rings 8, 11 and 14 attached to the upper ends of rod cylinders 10 and 13 of lower pistons 2 to 4 (in the case of cylinder 1, cylinder 7). FIG. 5 is a cross-sectional view of the main part of the upper end ring 8 of the cylinder 1 when the first piston 2 is fully moved up (the same applies to the upper end rings 11 and 14 of the second piston 3 and the third piston 4). A dust seal 40 that restricts entry of dust from above and an oil seal 41 that prevents pressure oil from leaking are fitted on the inner periphery of the upper end ring 8. In addition, a wear ring 42 is provided between the two to impregnate the pressure oil so that the piston head 9 of the first piston 2 slides smoothly.
[0025]
The air vent structure applied to the upper end ring 8 includes an air vent passage 43 formed in the air vent structure. The air vent passage 43 includes a lateral passage 43a that communicates the inner periphery and the outer periphery of the upper end ring 8, and a longitudinal passage 43b that communicates with the back pressure chamber 18 of the first piston 2 and joins the lateral passage 43a. The The lateral passage 43a is plugged with a plug 44 that is screwed into the terminal end. As described above, the piston head 9 of the first piston 2 in this example is formed with the connecting portion 9a and extends (the rod cylinder 10 is connected to the inner periphery). A space 45 is maintained between the pressure cylinder 18 and the cylinder cylinder 7.
[0026]
This is to ensure the smooth movement of the piston head 9 and the like by preventing the piston head 9 from falling by bringing only the connecting portion 9a into contact with the upper end ring 8 when the upper stroke end is reached. The vertical passage 43b is formed across the connecting portion 9a and the gap 45 so that either air can escape. Further, the joining point of the vertical passage 43 b that joins the horizontal passage 43 a is set on the inner peripheral side from the plug 44. If this confluence is at the position of the plug 44, the air may be caught and flow into the back pressure chamber 18 when the plug 44 is inserted when the air is released, and this is avoided. .
[0027]
【The invention's effect】
Since the present invention is as described above, that is, the air vent passage includes a lateral passage communicating with the inner periphery and the outer periphery of the upper end ring, and a longitudinal passage communicating with the back pressure chamber of the lower piston and joining the transverse passage. It is composed of. Therefore, not only the air that has passed through a part of the upper end ring and entered the rod cylinder of the upper piston facing the air vent passage, but also the air accumulated in the back pressure chamber of the piston described above. Since it can be extracted together, the air remaining in the back pressure chamber can be reduced as much as possible. Therefore, the pulsation and lowering of the elevator box can be prevented, and the ride quality is not deteriorated and the level difference is not caused.
[Brief description of the drawings]
FIG. 1 is a partial cross-sectional side view of a hydraulic jack according to the present invention in a contracted state.
FIG. 2 is a partially sectional side view of the hydraulic jack according to the present invention in an extended state.
FIG. 3 is a partial cross-sectional side view of a main part in a state where the hydraulic jack according to the present invention is contracted.
FIG. 4 is a side view of a state in which the hydraulic jack according to the present invention is applied for raising and lowering a home elevator.
FIG. 5 is an enlarged cross-sectional view of a main part of an upper end ring showing an example of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Cylinder 2 1st piston 3 2nd piston 4 3rd piston 7 Cylinder cylinder 8 Cylinder upper end ring 9 Piston head 9a of 1st piston Piston head connection part 12 of 1st piston Piston head 12a of 2nd piston Connecting portion 13 of the piston head of the two pistons Rod rod 17 of the second piston 17 Positive pressure chamber 18 of the first piston Back pressure chamber 19 of the first piston 20 Positive pressure chamber 20 of the second piston Back pressure chamber 21 of the second piston Third Piston positive pressure chamber 22 Third piston back pressure chamber 43 Air vent passage 43a Air vent passage horizontal passage 43b Air vent passage vertical passage 44 Plug 45 Air gap formed between piston head and rod cylinder

Claims (2)

The lower piston rod cylinder and the upper end ring attached to the upper end of the upper piston are inserted so that they can move up and down, and the back pressure chamber of the lower piston and the positive pressure chamber of the upper piston communicate with each piston. Each of the back pressure chambers is filled with pressure oil, and an air vent passage is formed in the upper ring to discharge air accumulated in the back pressure chamber when the back pressure chamber of the lower piston is filled. In the air vent structure in the formed multi-stage hydraulic jack, the air vent passage is connected to the inner passage and the outer periphery of the upper end ring by a plug and communicated with the back pressure chamber of the lower piston and the lateral passage. while composed of a longitudinal passage merging into, on top of the piston of the piston head, the connecting portions of the upper extending provided keeping the gap between the rod tube of the lower piston, the upper end of the connecting portion is lower piston Addition to those that upward movement to the upper end ring down contact is restricted, the air vent structure in a multi-stage hydraulic jack, characterized in that formed across the longitudinal passage and the connecting portion and the gap.   The air vent structure in the multistage hydraulic jack according to claim 1 or 2, wherein the longitudinal passage joins the lateral passage on the inner peripheral side from the plug.

Images