JPH08233016A - Hydraulic cylinder - Google Patents

Abstract

PURPOSE: To easily and rapidly assemble a cylinder and a lower cap by a simple structure while coaxiality having high accuracy is exhibited as well as to provide sufficient airtightness, by employing a simple seal structure. CONSTITUTION: A cylinder side taper part 2a is formed at the lower end of a cylinder 2, and a lower cap side taper part 7a is formed to a lower cap 7 opposed to the cylinder side taper part 2a. Further, a seal member 11 which is tightly fitted to be bitten into respective taper parts 2a, 7a by receiving the axial force of the cylinder 2 during an assembly period, is interposed between the lower cap side taper part 7a and the cylinder side taper part 2a.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a multi-cylinder type hydraulic cylinder used as a hydropneumatic suspension for automobiles.

[0002]

2. Description of the Related Art As a conventional double cylinder type hydraulic cylinder,
For example, as shown in FIG. 7 and FIG. 8, in the same figure, 1 is a piston that divides the interior of the cylinder 2 into two oil chambers 3 and 4, and 5 is the piston 1
It is a piston rod which is supported so as to slide inside.

An outer shell 6 is provided on the outer peripheral side of the cylinder 2.

Further, 7 is a lower cap for closing the lower end of the outer shell 6, and 8 is the lower cap 7
A lower case is provided coaxially inside and closes the lower end of the cylinder 2.

An O-ring 10 is inserted in a ring groove 9 formed on the outer periphery of the lower case 8 and is in close contact with the inner periphery of the lower end of the cylinder 2 to seal the oil in the cylinder 2.

As shown in FIG. 8, the lower cap 7 has a tapered portion 7a on the upper surface and a tapered portion 8a on the lower surface of the lower case 8 on the tapered portion 7a.
The lower cap 7 and the lower case 8 are aligned with each other by bringing the lower cap 7 and the lower case 8 into contact with each other.

[0007]

However, in the above-mentioned conventional hydraulic cylinder, the O-ring 10 is used to secure the airtightness by mounting the cylinder 2 on the lower case 8.
Therefore, it is necessary to form the ring groove 9 for mounting the O-ring 10 in the lower case 8 itself, and it takes time to perform the cutting process for forming the ring groove 9 and the processing cost is increased. There was a problem such as becoming expensive.

Since the cylinder 2 is fixed to the lower cap 7 via the lower case 8,
It becomes difficult to obtain the coaxiality between the cylinder 2 and the lower cap 7, and when the coaxiality cannot be sufficiently obtained, the frictional resistance between the piston rod 5 and the seal portion above the outer shell 6 becomes large. There was a problem.

Further, the cylinder 2, the outer shell 6,
Lower case 8, lower cap 7 and O-ring 10
Since these are assembled according to a fixed procedure, the number of parts is large and the workability during assembly is extremely poor.

The present invention has been made to solve the above-mentioned conventional problems, and by adopting a simple seal structure, the cylinder and the lower cap can be sufficiently airtight. An object of the present invention is to obtain a hydraulic cylinder that can be easily and quickly assembled with a simple structure while providing a highly accurate coaxiality.

It is another object of the present invention to obtain a hydraulic cylinder which can be easily and quickly mounted by adopting a simple seal structure while providing coaxiality in assembling the cylinder and the lower case.

A further object of the present invention is to obtain a hydraulic cylinder which allows easy and quick assembly of the cylinder and the base valve while providing coaxiality.

[0013]

According to a first aspect of the present invention, there is provided a hydraulic cylinder including a piston for partitioning the interior of the cylinder into two oil chambers, and a piston rod for slidably supporting the piston in the cylinder. A hydraulic cylinder comprising an outer shell provided on the outer peripheral side of the cylinder and a lower cap closing the lower end of the outer shell, wherein a cylinder side taper portion is formed at the lower end of the cylinder, and the cylinder side taper portion is formed. A tapered portion on the lower cap side is formed on the lower caps that face each other, and a tight seal is formed between the tapered portion on the lower cap side and the tapered portion on the cylinder side so as to receive the axial force of the cylinder during assembly and to bite into each tapered portion. The sealing material to be fitted is interposed.

A hydraulic cylinder according to the invention of claim 2 is
A piston that divides the inside of the cylinder into two oil chambers, a piston rod that slidably supports the piston in the cylinder, an outer shell provided on the outer peripheral side of the cylinder, and a lower that closes the lower end of the outer shell. A cap,
A hydraulic cylinder provided coaxially in the lower cap and having a lower case for closing a lower end of the cylinder, wherein a cylinder side taper portion is formed at a lower end of the cylinder, and the cylinder side taper portion is opposed to the cylinder side taper portion. The lower case side taper portion is formed in the lower case, and the lower case side taper portion and the cylinder side taper portion are tightly fitted to each other by receiving the axial force of the cylinder during assembly. The sealing material is interposed.

A hydraulic cylinder according to a third aspect of the invention is
A piston that divides the inside of the cylinder into two oil chambers, a piston rod that slidably supports the piston in the cylinder, and a piston rod that is provided on the outer peripheral side of the cylinder and that penetrates the cylinder into the cylinder. An outer shell that introduces corresponding oil, a lower cap that closes the lower end of the outer shell, and a coaxially provided inside the lower cap to support the lower end of the cylinder and to partially cover the damping force generating valve. And a base valve that forms a base valve side taper part formed on the base valve facing the cylinder side taper part. A tight fit between the valve side taper part and the cylinder side taper part so as to receive the axial force of the cylinder during assembly and to bite into each taper part. It is one in which a sealing member is interposed.

[0016]

In the hydraulic cylinder of the first aspect of the present invention, a sealing material such as copper packing is interposed between the lower cap side taper portion of the lower cap to which the outer shell is attached and the cylinder side taper portion at the lower end of the cylinder. By applying an axial force toward the lower cap side to the cylinder, while deforming the sealing material, the lower cap side taper portion and the cylinder side taper portion are bitten into it.
These are fitted and integrated in an airtight state while maintaining coaxiality with each other.

In the hydraulic cylinder according to the second aspect of the present invention, an axial force is applied to the taper portion on the cylinder side of the cylinder via the seal material, with respect to the taper portion on the lower case side of the lower case arranged on the lower cap. While deforming the sealing material, the lower case side taper portion and the cylinder side taper portion are made to bite into the sealing material,
The airtight state is obtained, and the axes of these tapered portions are aligned at the same time.

In the hydraulic cylinder according to the third aspect of the present invention, an axial force is applied to the taper portion on the base valve side of the base valve arranged on the lower cap through the seal material to the taper portion on the cylinder side of the cylinder. While deforming the sealing material, the base valve side taper portion and the cylinder side taper portion are made to bite into the seal material to achieve axial alignment and airtightness between these taper portions.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIGS. 1 and 2 are a sectional view and an enlarged sectional view showing an essential part of a hydraulic cylinder of the present invention. 2 is a cylinder, 6 is an outer shell, 7 is
A ring-shaped sealing material 1 made of copper packing or the like between the lower end of the cylinder 2 and the inner peripheral surface of the lower cap 7 facing the outer periphery of the lower end, which is a lower cap.
1 is installed.

Further, the cylinder 2 has a cylinder side taper portion 2a formed on the outer periphery of the lower end portion as shown in FIG. 2, and the inner peripheral surface of the lower cap 7 attached to the lower end of the outer shell 6 is formed. A tapered portion 7a on the lower cap side is formed on an upper portion, and a ring-shaped step groove 7 is formed on a lower portion of the tapered portion 7a.
b are arranged in series.

In this embodiment, the taper portion 7a on the lower cap side is equal to the inclination of the step groove 7b, and is larger than the inclination of the taper portion 2a on the cylinder side.

The sealing material 11 has a ring shape with a vertically long rhombus cross section, and the upper surface has a uniform height with the upper surface of the lower cap 7, and the inner and outer surfaces are inclined surfaces substantially equal to the taper portion 7a on the lower cap side. Has been done.

In addition to the above copper packing, the sealing material 11 is formed of a soft metal material such as aluminum, resin, rubber or the like.

The sealing by the seal 11 between the cylinder 2 and the lower cap 7 is performed as follows.

First, the outer shell 6 as shown in FIG.
The sealing material 11 is inserted into the lower cap 7 to which is attached so that the inclined surface is joined to the tapered portion 7a on the lower cap side.

Subsequently, the cylinder 2 is inserted into the outer shell 6 from above, and the cylinder side taper portion 2a at the lower end of the cylinder 2 is abutted against the inclined inner peripheral surface of the sealing material 11, and a strong axial force is applied. Then, the cylinder 2 is vertically pushed downward.

As a result, the cylinder side taper portion 2a is formed.
Means that the sealing material 11 is attached to the taper portion 7a on the lower cap side.
While being pressed against, it gradually bites into the sealing material 11, and the sealing material 11 deformed by this biting bites into the ring-shaped staircase groove 7b.

Therefore, the sealing material 11 fills the scratches and notches in the lower cap side taper portion 7a and the cylinder side taper portion 2a, and the vicinity of the cylinder side taper portion 2a and the space between the lower cap side taper portion 7a are airtight. Will be sealed.

That is, this sealing structure is applied to the sealing material 1.
It can be easily and quickly formed by the axial force press-fitting of the end of the cylinder 2 following the insertion of 1 into the lower cap 7, and the axial force is urged downward while the cylinder side taper portion 2a is guided by the inclined surface of the seal material 11. This seal material 1
The cylinder 2 is placed in the outer shell 6 in which 1 is coaxially arranged.
Can be arranged coaxially.

FIG. 4 shows another embodiment of the present invention in which a mounting ring 12 for mounting a cylinder is projected on the upper surface of a lower cap 7A mounted on the lower end of the outer shell 6, A seal material 11A is fitted and inserted into a taper portion 12a on the lower cap side on the outer periphery of the mounting ring 12, and a taper portion 2b on the cylinder side is fixed to the seal material 11A.

Also in this embodiment, a step groove (not shown) similar to that of the above-mentioned embodiment is continuously provided at a part of the lower cap side taper portion 12a of the mounting ring 12 so that an axial force is applied to the cylinder 2. By applying, the cylinder side taper portion 2b bites into the sealing material 11A, and the sealing material 11
The cylinder 2 is held in close contact with the lower cap 7A via A.

In this embodiment, the cylinder 2
11A is provided on the inner peripheral side, and the outer peripheral surface of the cylinder 2 and the inner peripheral surface of the outer shell 6 are close to each other,
This is advantageous when there is not enough room for the sealing material.

FIG. 5 shows another embodiment of the present invention, in which a lower case 8 is coaxially mounted on a lower cap 7B, and a mounting ring for mounting a cylinder on the lower case 8 is mounted. A lower case side taper portion 8a is formed on the outer periphery of 13, and a cylinder side taper portion 2b at the inner periphery of the lower end of the cylinder 2 is fitted to the lower case side taper portion 8a via a sealing material 11. is there.

In this embodiment, by applying an axial force to the cylinder 2 to press the cylinder side taper 2b into the seal material surface 11, the airtight sealing of the cylinder 2 with respect to the lower case 8 and the axial alignment are achieved. Simultaneously via 11.

This embodiment is effective when the lower cap side taper portion cannot be formed on the lower cap 7B for the convenience of manufacturing the lower cap 7B, or when the lower case 8 can be manufactured at a sufficiently low cost. In this case,
Compared to the conventional structure in which the O-ring is installed in the lower case, the efficiency of the assembling work and the processing cost can be reduced.

FIG. 6 shows still another embodiment of the present invention. In this embodiment, a base valve 14 is provided at the lower end of the cylinder 2, and the base valve 14 and the cylinder 2 are provided.
A sealing material 15 such as copper packing is interposed between the lower end and the lower end.

The base valve 14 has a notched oil passage 16 which communicates with the outer shell 6 on the lower cap 7C.
A ring member 17 having an opening, an orifice plate 19 mounted on the ring member 17 via a valve mounting member 18, and a leaf valve for opening and closing an orifice 20 provided on the orifice plate 19 in response to changes in hydraulic pressure. 21 and.

Further, 17a is a base valve side taper portion formed on the outer circumference of the ring member 17, and a seal material 15 such as copper packing is brought into contact with the base valve side taper portion 17a. On the other hand, the cylinder side taper portion 2b at the lower end portion of the cylinder 2 is press-fitted by using the same axial force as described above.

Also in this embodiment, a step groove (not shown) is continuously provided on the base valve side taper portion 17a, if necessary.

This embodiment is effective when applied to a hydraulic cylinder that obtains a damping force in a region where the operating speed is low by adding a base valve 14, and also the axial alignment of the cylinder 2 and the outer shell 6 is airtight. It can be done at the same time while securing.

Therefore, according to each of the above-described embodiments, the sealing structure can be easily and simply by applying the axial force to the cylinder 2 without processing the ring groove for accommodating the O-ring in the conventional case into the lower case or the like. It is possible to realize a structure that can be realized at a low cost and that the coaxial accuracy between the cylinder 2 and the outer shell 6 can be sufficiently obtained, and therefore the sliding resistance of the piston rod can be reduced and the assemblability and productivity can be improved. .

[0042]

As described above, according to the first aspect of the invention, the piston that divides the inside of the cylinder into the two oil chambers, the piston rod that slidably supports the piston inside the cylinder, and the above-mentioned piston rod are provided. A hydraulic cylinder comprising an outer shell provided on the outer peripheral side of a cylinder and a lower cap closing the lower end of the outer shell, wherein a cylinder side taper portion is formed at the lower end of the cylinder, and the cylinder side taper portion is opposed to the cylinder side taper portion. The lower cap side taper portion is formed in the lower cap, and the lower cap side taper portion and the cylinder side taper portion are tightly fitted between the lower cap side taper portion and the cylinder side taper portion so as to receive the axial force of the cylinder at the time of assembly and bite into the respective taper portions. Since it is configured to interpose a seal material that is used, a simple seal structure is adopted to obtain sufficient airtightness between the cylinder and the lower cap. While producing high precision concentricity of,
The effect is that a simple structure that can be easily and quickly assembled is obtained.

According to the second aspect of the present invention, a piston that divides the interior of the cylinder into two oil chambers, a piston rod that slidably supports the piston within the cylinder, and a piston rod provided on the outer peripheral side of the cylinder are provided. A hydraulic cylinder comprising an outer shell, a lower cap that closes a lower end of the outer shell, and a lower case that is coaxially provided in the lower cap and closes a lower end of the cylinder. A cylinder side taper portion is formed, and a lower case side taper portion is formed in the lower case facing the cylinder side taper portion, and a cylinder shaft at the time of assembly is formed between the lower case side taper portion and the cylinder side taper portion. Since a seal material that is tightly fitted so as to bite into each of the above-mentioned taper portions by receiving force is interposed, a simple seal structure can be adopted. In, while sufficiently out of concentricity assembling the cylinder and the lower case, easily, there is an effect to be obtained which can be performed quickly.

According to the third aspect of the present invention, a piston that divides the interior of the cylinder into two oil chambers, a piston rod that slidably supports the piston within the cylinder, and a piston rod provided on the outer peripheral side of the cylinder are provided. An outer shell that introduces oil according to the intrusion volume of the piston rod into the cylinder, a lower cap that closes the lower end of the outer shell, and a coaxially provided inside the lower cap that connects the lower end of the cylinder. A hydraulic cylinder that is supported and that includes a base valve that forms a part of the damping force generating valve, wherein the cylinder side taper portion is formed at the lower end of the cylinder, and the base valve is opposed to the cylinder side taper portion. A base valve side tapered portion is formed on the base valve side and the cylinder side tapered portion receives the axial force of the cylinder during assembly. And then, it is interposed a sealing material which is tightly fitted to bite into the respective tapered portion,
The cylinder and the base valve can be assembled easily and quickly while maintaining coaxiality, and the desired damping force can be stably generated.

[Brief description of drawings]

FIG. 1 is a sectional view of essential parts showing a hydraulic cylinder according to an embodiment of the present invention.

FIG. 2 is a cross-sectional view showing an enlarged main part of the hydraulic cylinder in FIG.

3 is a cross-sectional view of a main part showing an assembled state of the hydraulic cylinder in FIG.

FIG. 4 is a sectional view of essential parts showing a hydraulic cylinder according to another embodiment of the present invention.

FIG. 5 is a cross-sectional view of essential parts showing a hydraulic cylinder according to another embodiment of the present invention.

FIG. 6 is a sectional view of essential parts showing a hydraulic cylinder according to another embodiment of the present invention.

FIG. 7 is a sectional view showing a conventional hydraulic cylinder partially broken away.

8 is an enlarged cross-sectional view showing a main part of the hydraulic cylinder in FIG.

[Explanation of symbols]

 1 Piston 2 Cylinder 2a Cylinder side taper part 3,4 Oil chamber 5 Piston rod 6 Outer shell 7, 7A, 7B, 7C Lower cap 7a, 12a Lower cap side taper part 7b Stair groove 8 Lower case 8a Lower case side taper part 11 , 15 Seal material 14 Base valve 17a Base valve side taper part

Claims (3)

[Claims] 1. A piston for partitioning a cylinder into two oil chambers, a piston rod for slidably supporting the piston in the cylinder, an outer shell provided on the outer peripheral side of the cylinder, and the outer shell. In a hydraulic cylinder including a lower cap closing the lower end of the cylinder, a cylinder side taper portion formed on the lower end of the cylinder, and a lower cap side taper portion formed on the lower cap facing the cylinder side taper portion, And a seal member which is interposed between the lower cap side taper portion and the cylinder side taper portion, and which is tightly fitted so as to bite into the respective taper portions upon receiving the axial force of the cylinder during assembly. Characteristic hydraulic cylinder. 2. A piston that divides the interior of the cylinder into two oil chambers, a piston rod that slidably supports the piston in the cylinder, an outer shell provided on the outer peripheral side of the cylinder, and the outer shell. In a hydraulic cylinder including a lower cap closing the lower end of the cylinder and a lower case coaxially provided in the lower cap and closing the lower end of the cylinder, a cylinder side taper portion formed at the lower end of the cylinder, The lower case side taper portion formed on the lower case facing the cylinder side taper portion, and interposed between the lower case side taper portion and the cylinder side taper portion to receive the axial force of the cylinder during assembly. And a sealing material that is tightly fitted so as to bite into each of the tapered portions. 3. A piston which divides the inside of the cylinder into two oil chambers, a piston rod which slidably supports the piston in the cylinder, and a cylinder of the piston rod which is provided on the outer peripheral side of the cylinder. An outer shell that introduces oil according to the intrusion volume with respect to the lower shell, a lower cap that closes the lower end of the outer shell, and a coaxially provided inside the lower cap that supports the lower end of the cylinder and generates the damping force. In a hydraulic cylinder provided with a base valve forming a part of a valve, a cylinder side taper portion formed at a lower end of the cylinder and a base valve side taper formed on the base valve facing the cylinder side taper portion. And the base valve side taper portion and the cylinder side taper portion, and receives the axial force of the cylinder during assembly. A hydraulic cylinder, characterized in that a sealing material which is tightly fitted so as to bite into each taper portion is provided.