JPS63308202A - Piston-cylinder unit - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The invention relates to a piston-cylinder unit having the features of the preamble of claim 1.

PRIOR ART AND THE PROBLEM TO BE SOLVED BY THE INVENTION Piston-cylinder units of this type are known in various constructions and for different applications. Alternatively, there are double-acting power cylinders and piston accumulators with a damping function at the end of one stroke. The requirements for such a unit are first to throttle the flow of hydraulic oil displaced during the forward stroke of the piston to an extent sufficient to obtain the desired damping effect as the piston approaches its end position. On the other hand, during the reverse return stroke of the piston from its end position, it is extremely important that the pressure oil that starts the return stroke movement is supplied to the piston in such a way that it is not affected by the throttle as much as possible. Delays in the movement of the piston can only be avoided if it is possible to utilize a large flow rate for the return stroke, which is as unaffected as possible by the throttling. Such delays are disadvantageous in many applications.

There are also cases where it is unacceptable.

Therefore, everyone tries to make the cross-sectional area of the flow path with the check valve and bypassing the damping gap of the end position damping means as large as possible.

However, structural difficulties arise in conventionally fitting this flow path and associated check valve within the cylinder cover. Because the available construction space of the cylinder cover area is.

This is because it is generally insufficient to accommodate a sufficiently large check valve to which an oil conduit is connected. Therefore, until now,
Pressure oil for the return stroke was made to pass through an external pipe and a check valve attached to the outside of the cylinder cover. but.

Such structures are bulky and expensive to manufacture.

The object of the invention is not only to feature a simple design that can be inexpensive to manufacture, but also to provide a rapid piston response during the return stroke movement by activating a relatively large flow of pressure oil to the piston. The object of the present invention is to produce a piston-cylinder unit of the type mentioned here, which is characterized by the following.

(Means for solving the problem) This object is achieved according to two aspects of the invention by a piston-cylinder unit consisting of:

(a) a piston capable of actuating a hydraulic fluid on at least one side of the piston, said piston having a damping piston portion projecting from a piston surface, said piston having said piston for damping the end position of said piston; The one that operates oil on the damping piston part of.

(b) In the damping chamber at the end of the cylinder.

It is possible to connect to the hydraulic connection and move there the said damping piston part, thereby forming a damping gap, through which the said piston approaches the said end position. , capable of supplying the aforementioned connection with the pressure oil displaced by the piston pressure-receiving main surface surrounding the aforementioned damping piston part.

(c) A flow path equipped with a check valve, through which pressure oil can be supplied from the above-mentioned connection to the pressure chamber adjacent to the above-mentioned piston pressure-receiving main surface; which bypasses the aforementioned damping gap by.

Said unit comprises at least one of said damping piston parts in which said flow path with said check valve connects in said piston with said connection when said piston is in said end position. characterized in that it extends between one inlet port and at least one outlet port of said piston portion opening into said pressure chamber adjacent said piston pressure receiving major surface.

In the solution according to the invention, the piston.

Together with the associated damping piston part, it provides a structural space for the flow path, through which the pressure oil reaches the main piston pressure surface through the aforementioned flow path and starts the return stroke of the piston, thereby bypassing the damping gear 7. do. In such a configuration, for example.

Particularly compact cylinder designs with cylinder covers that are screwed onto the end of the cylinder and do not protrude laterally beyond the cylinder shell do not require any external piping or external installation of non-return valves. Therefore, it is easy to ensure an appropriate cross section for the flow path. Therefore, a simple, inexpensive and compact design provides reliable piston response during the return stroke.

In an advantageous embodiment as defined in claim 2, the arrangement is such that the damping piston part forms a sleeve;
The aforementioned sleeve opens at and projects from the forward end of the piston, the forward end opening of the sleeve serves as an inlet port for a flow passage with a check valve, and the sleeve wall is axially spaced apart from the forward end inlet port. There is one opening at the position where the opening is located.

from the inside of the sleeve to the pressure chamber adjacent to the piston pressure-receiving main surface and serving as an outlet port for a flow path with a check valve provided in the sleeve in the area between the inlet port and the outlet port. . In such embodiments.

The damping piston part in the form of a sleeve becomes the valve housing of the check valve.

As defined in claim 3, the check valve is of the ring-plate valve type, comprising a movable valve plate guided on the inner wall of the sleeve, and a ring-shaped valve seat provided at the front end of the sleeve. A particularly large valve cross-section is obtained in the flow path if the valve defines the inlet port by its ring inner diameter. That is, a cross-section of the valve is obtained with the valve plate covering the entire free cross-sectional area inside the sleeve, the inlet cross-section of the valve corresponding to the free cross-sectional area of the ring bore of the ring-shaped valve seat.

(Operations, Examples and Effects of the Invention) The present invention will now be described in detail with reference to embodiments shown in the accompanying drawings.

FIG. 1 shows a longitudinal section through an embodiment in the form of a hydro-pneumatic piston type accumulator, with the piston in a position corresponding to the end of the return stroke movement.

FIG. 2 is a sectional view corresponding to FIG. 1.

The piston is in the position just after starting the return stroke movement from the advanced piston end position.

The hydro-pneumatic piston type accumulator shown in FIGS. 1 and 2 consists of a cylinder 1 and a rear cylinder cover 3 shown at the top of the figures, the rear cylinder cover being fixed by a threaded ring 5, which is connected to the cylinder. It is screwed into the internal thread 6 at the rear end of 1. The rear cylinder cover 3 has a central hole 7 with an internal thread.

A plug 9 is inserted into the center hole to airtightly seal the hole 7. The plug 9 has a central hole 11 with an internal thread, and the orifice opening at its outer end is hermetically sealed by a m13 screwed over the plug 9 from the outer end.

1 after removing the lid 13, although not shown in the figure.

Screw the filling valve into the female thread of hole 11 of plug 9.

Gas can be enclosed in the gas chamber 14 located between the cylinder cover 3 and the piston 15 freely moving within the cylinder 1 to generate a gas pressure cushion at the desired pressure. The rear cylinder cover 3 and the piston 15 are sealed against the inner wall of the cylinder by seal rings 17 and 19, respectively. At the front end, ie at the bottom of the figure, the cylinder 1 likewise has an internal thread 21.

The front cylinder cover 23 is screwed into this female thread. The cylinder cover 23 is sealed against the inner wall of the cylinder l by a seal ring 24. A central hole 25 extends through the cylinder cover 23.

It has a female thread for threaded connection with a pressure oil connection fitting.

The piston 15 has, on the side associated with the gas chamber 14,
The bottom of the piston has a recess 27 in which the compressed gas pressure cushion of the gas chamber 14 is accommodated when the piston 15 is in the fully retracted position as shown in FIG. On the opposite side relating to the pressure oil, the piston 15 has a centrally arranged damping piston part 31 in the form of a cylindrical cylinder, which projects from the main pressure-receiving surface 29 of the piston. In the illustrated embodiment, the damping piston part 31 and the remainder of the piston 15 are of one-piece construction. The damping piston part 31 is provided to cooperate with a damping chamber 32 in the form of a central recess inside the cylinder cover 23, which damping chamber is aligned with the damping piston part 31 and has a central recess for the pressure oil. Connected to hole 25.

As is common with end position damping means with a damping piston part that can be moved into the damping chamber,
The outer diameter of the damping piston part 31 and the inner diameter of the damping chamber 32, as well as the beveled edge 33 on the damping piston part 31. These two with beveled edges 35,36 on the inner wall of the damping chamber
The two-part design is formed in such a way that when the damping piston part 31 is moved into the damping chamber 32, a damping gap 38 (see FIG. 2) is created between the opposing walls. When the piston 15 approaches its forward end position (lower part of the figure), the pressure oil removed from the adjacent pressure chamber 40 (see FIG. 2) by the piston pressure-receiving main surface 29 passes through the damping gap 38 and increases the pressure. It is fed towards the oil connection or central hole 25. In the damping gap the pressure oil is subjected to throttling.

The damping piston part 31 is in the form of a sleeve with a centrally arranged and axially extending interior space 43 . This internal space 43 opens to the front end surface 45 of the damping piston part 310,
A valve housing for a ring-plate type check valve 47 is provided with a movable valve plate 48 that is movably guided along the inner wall of the internal space 43. Front end surface 4 of damping piston portion 31
In the area adjacent to 5, the sleeve-shaped internal space 43
has a female thread into which a ring-shaped valve seat 49 of a check valve 47 is screwed. The valve plate 48 is normally pressed against the inner end of the ring-shaped valve seat 49 under the spring force of the valve spring 51. The aforementioned valve spring.

In this embodiment, one coil spring is supported on the end face of the valve plate 48 remote from the ring-shaped valve seat 49, and the other is supported on the bottom surface 52 of the internal space 43.

In the area displaced from the ring-shaped valve seat 49 by the inner end force, the wall of the sleeve forming the damping piston part 31 has a piston pressure-receiving main surface 2 extending outwardly from the inner space 43 and further outwardly.
An opening 55 is provided which opens into a partial area of the pressure chamber 40 adjacent to the pressure chamber 9 .

This frontage 55 forms, together with the interior space 43, an internal flow path in which an inlet port is formed by the ring bore 57 of the ring-shaped valve seat 49 and an outlet port is formed by the opening 55. This flow path is closed and opened by a check valve 47 in an intermediate position.

In FIG. 1, pressure oil supplied from the connection hole 25 is connected to the piston 1.
5, and further shows an operating mode in which the gas pressure cushion on the rear end side of the piston is compressed into the gas chamber in the recess 27. When the oil pressure drops, the piston 15 moves forward. Then, check valve 4
The valve plate 48 of No. 7 is pressed against the ring-shaped valve seat 49. because.

This is because when the oil pressure in the central hole 25 falls, the internal oil pressure in the internal space 43 of the sleeve housing the check valve becomes dominant (this pressure corresponds to the previously existing operating pressure). therefore.

As the piston 15 approaches the end of its forward movement.

Once the damping piston part 31 enters the damping chamber 32.

The pressure oil removed from the pressure chamber 40 is forced through the damping gap 38 by the piston pressure receiving main surface 29 . In the damping gap the pressure oil is subjected to a throttling, whereby the desired end position damping is achieved.

If the pressure in the area of the connecting central hole 25 subsequently increases, 1
Piston 15 can begin its return stroke substantially without delay before a possible unacceptable pressure peak occurs. This is important, and the connection center hole 2
When the pressure of 5 increases, not only does the pressure oil act on the front end surface 45 of the damping piston part 31, but also the damping gap 38
This can also be ensured by a flow path that bypasses the The flow path is from the ring bore 57 of the check valve 47, which serves as an inlet port, directly to the pressure chamber via the opening 55.
40, and as a result of the increase in the oil pressure on the front end side of 1, the valve plate 48 is lifted from the ring-shaped valve seat 49.
That is, when the check valve 47 opens, it immediately communicates with the piston pressure receiving main surface 29.

Therefore, the pressure oil acts on the piston pressure-receiving main surface 29 without being throttled by the damping gap 38, 1 so that the piston 15 can return substantially without delay. FIG. 2 shows the operating mode immediately after the check valve 47 is in the open position and one return stroke has started.

As is clear from the attached figures, it is possible to have a considerable cross-section for the internal flow path with the check valve 47 and bypassing the damping gap 38 without any structural difficulties occurring. In particular, the large diameter of the valve plate 48 and the annular valve seat 49, which may approximately correspond to the diameter of the piston, results in a large usable flow cross-section within the valve. If necessary.

In order to increase the exit cross-sectional area of the exit port of the internal flow path,
More than one aperture 55 may be provided.

All features mentioned in the above description and which are apparent from the accompanying drawings are to be understood as developments within the scope of the invention, even if they are not specifically emphasized or stated in the claims. be.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional side view of an accumulator according to an embodiment of the present invention when the upper end of the piston is rising, and FIG. 2 is a longitudinal sectional side view when the piston starts to rise. (1)...Cylinder, (3)...Rear cylinder cover, (5)...Threaded ring, (6)...Female thread, (7)...Central hole, (9)...・Plug, (11)
...Central hole, 03)...Lid, Circle...Gas chamber, 05)...Piston, 07)09)(24)...
・Seal ring, (21)...Female thread, (23)...
・Front cylinder cover, (25)...Central hole, (27
)...Concave portion, (29)...Piston pressure receiving main surface,
(31) Damping piston part, (32) Damping chamber, (33) (35) (36) Slope edge, (38) Damping gap, (40) Pressure Chamber, (43)...Inner space, (45)...Front end surface, (47)...Check valve, (48)...Valve plate,
(49)...Ring-shaped valve seat, (51)...Valve spring,
(52)...bottom, (55)...opening, (57)...
...Ring inner hole.

Claims (4)

[Claims] (1) A piston-cylinder unit comprising: (a) a piston capable of actuating pressurized oil on at least one side of the piston, said piston having a damping piston portion projecting from the piston surface; The oil is actuated on the damping piston part mentioned above to damp the end position of the damping piston. (b) a damping chamber at the end of the cylinder, which is connected to the hydraulic oil connection and into which it is possible to move the said damping piston part, thereby forming a damping gap so that the said piston is (c) capable of supplying said connection with pressurized oil which, when approaching the end position of said gap, is displaced by the piston pressure-receiving main surface surrounding said damping piston part; and (c) a non-return check. A channel provided with a valve, via which it is possible to supply pressure oil from the aforementioned connection to the pressure chamber adjacent to the aforementioned main pressure receiving surface of the piston, thereby eliminating the aforementioned damping gap. The said flow path with the said non-return valve (47) is arranged in the said piston (15) in the said piston (15) when the said piston is in the said end position. at least one inlet port of the aforementioned damping piston part (31) connected with the aforementioned piston (15) and opening into the aforementioned pressure chamber (40) adjacent to the aforementioned piston pressure-receiving main surface (29); extending between at least one outlet port of the. (2) A piston-cylinder unit according to claim 1, in which the damping piston part (31) is formed as a sleeve, the sleeve opening at the front end of the piston (15) and extending therefrom. The forward end opening of said sleeve projects from said sleeve and acts as an inlet port for said flow path with said check valve (47), further said sleeve wall extends axially relative to said forward end inlet port. at least one aperture (55) at a spaced apart position, said aperture extending from the inside of said sleeve into said pressure chamber (40) adjacent said piston pressure-receiving surface; characterized in that it acts as the outlet port of the aforementioned flow path, with the aforementioned check valve (47) being provided in the aforementioned sleeve in the area between the inlet port and the outlet port. (3) The piston-cylinder unit according to claim 2, comprising a ring-plate type valve as a check valve (47), and a movable valve plate (48) of the ring-plate type valve. is guided on the inner wall of the aforementioned sleeve, and the ring-shaped valve seat (49) of the aforementioned ring-plate type valve is guided on the front end (49) of the aforementioned sleeve.
5), characterized in that the ring bore (57) defines the aforementioned inlet port. (4) The piston-cylinder unit according to claim 3, one of which is supported by the bottom surface (52) of the inner end of the sleeve,
On the other hand, it is characterized by a coil spring (51) supported on the end face of the aforementioned valve plate (48) remote from the ring-shaped valve seat (49).