JP2001116002A - Method for manufacturing accumulator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing an accumulator capable of shortening manufacturing time and reducing cost based on efficient manufacturing procedures and a favorable welding method. SOLUTION: A cylindrical shell 10 of an accumulator is composed of a bottom shell 20 and a cap shell 30 which are axially parted from each other. A bellows 40 is installed on a port 50 in which a communication passage 50a to a hydraulic circuit is formed, and the port 50 is projection-welded to the cap shell 30. With a bottom shell 20, a plug retainer 60 having a gas introducing port 60a is projection-welded. After that, the bottom shell 20 and the cap shell 30 are projection-welded to each other, thereby the shell 10 containing the bellows 40 is composed inside.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing an accumulator used in a hydraulic circuit of a hydraulic control device, and more particularly to a technique for improving the efficiency of a manufacturing process and reducing costs.

[0002]

2. Description of the Related Art In the above accumulator, the inside of a cylindrical shell is generally divided into a gas chamber and an oil chamber by a bellows, and the pressure fluctuation of oil flowing into the oil chamber is controlled by the expansion and contraction of the bellows. As a component that buffers by expansion and contraction and effectively suppresses pulsation generated in oil flowing in a hydraulic circuit, it is widely applied to, for example, a hydraulic circuit of an automobile. As a configuration of the accumulator, there is a type in which a cap is screwed into an opening of a bottomed cylindrical shell body. In this case, the cap is formed by using a processing means such as forging or cutting, and furthermore, both are formed. The necessity of forming the screw has led to an increase in cost. Therefore, there is provided an accumulator in which two shell divided bodies formed by press molding are joined by welding.

[0003]

In order to weld the shell divided bodies as described above, a welding method such as gas welding or TIG welding has conventionally been adopted. Also, inside the shell, there are cases where accessory parts such as a port formed with a communication passage to the hydraulic circuit and a plug retainer to which a plug for sealing the gas chamber is attached are fixed, but the fixing means is also,
It was by a similar welding method. However, such a welding method takes a long time and is inferior in mass productivity, resulting in an increase in cost. Therefore, there is a problem that the cost reduction effect by forming the shell divided body by press forming is weakened. Was. Therefore, an object of the present invention is to provide a method of manufacturing an accumulator that can reduce manufacturing time and cost based on an efficient manufacturing procedure and a suitable welding method.

[0004]

According to a first aspect of the present invention, an oil chamber communicating with a hydraulic circuit is provided inside a shell formed by joining two split shells divided in an axial direction. A method for manufacturing an accumulator in which a buffer material partitioned into a gas chamber in which gas is sealed is incorporated, wherein a port in which a communication path to the hydraulic circuit is formed communicates with the communication path, and the inside of the port is oiled. A buffer is attached to the chamber and the outside is partitioned into the gas chamber, and this port is connected to the gas chamber through a first step of fixing the port to one of the shell divisions by resistance welding and the other shell division. A second step of fixing the plug member having the gas inlet formed by resistance welding, and a third step of joining the respective shell divided bodies to each other by resistance welding to form a shell containing the buffer material therein. Features to prepare It is.

[0005] The accumulator according to the first aspect of the present invention comprises:
The inside of the cushioning material forms an oil chamber, and the space between the cushioning material and the shell forms a gas chamber. According to the present invention, the port and the plug member are fixed to each shell divided body by resistance welding, and thereafter, the shell divided bodies are joined by resistance welding. In resistance welding, welding is completed almost instantaneously at the same time as electricity is supplied to the electrodes brought into contact with the two members to be welded, so that the working time is greatly reduced, thereby improving mass productivity and reducing costs.

According to a second aspect of the present invention, there is provided a gas in which a gas is sealed in an inside of a shell formed by joining two shell divided bodies divided in an axial direction, and an oil chamber communicating the inside with a hydraulic circuit. A method of manufacturing an accumulator incorporating a cushioning material partitioned into a chamber, wherein one of the shell divided bodies includes:
A first step of fixing a port formed with a communication passage to the hydraulic circuit by resistance welding, and a plug member formed with a gas introduction port communicating with a gas chamber, and communicating with the gas introduction port to form an inside thereof. A second step of attaching a cushioning material for partitioning the outside into an oil chamber to the gas chamber and fixing the plug member to the other shell divided body by resistance welding, and joining the shell divided bodies to each other by resistance welding. And a third step of forming a shell containing a cushioning material therein.

[0007] The accumulator according to the second aspect of the present invention comprises:
The inside of the cushioning material constitutes a gas chamber, and the space between the cushioning material and the shell constitutes an oil chamber. The effect achieved is the same as in the first invention. The first of the above inventions
And the second step may be performed in this order, or the order may be reversed. Further, both may be performed in parallel. As a type of resistance welding, so-called projection welding in which a projection is formed on at least one of the joints is preferable from the viewpoint of sufficiently securing the joint strength.

In each of the above-mentioned inventions, the port and the plug member are fitted from the inside of the shell divided body, and are engaged with the port and the plug member in the fitted state with the inner surface of the shell divided body. In a preferred embodiment, a step is formed to regulate the movement of the shell to the outside of the shell. According to this aspect, the step portion engages with the inner surface of the shell divided body, so that the port and the plug member are securely prevented from coming off from the shell, and the port and the plug member can be prevented from rising due to an increase in the internal pressure of the shell. Dropout is prevented.

[0009]

Next, an embodiment of the present invention will be described with reference to the drawings. FIG. 1 shows a vertical cross section of an accumulator according to one embodiment of the present invention, and reference numeral 10 in the drawing.
Is a cylindrical shell, and 40 is an oil chamber 11 inside the shell 10.
Metal bellows (buffer material) partitioned into a gas chamber 12 and
Reference numeral 50 denotes a port forming a communication passage on the oil chamber 11 side, and reference numeral 60 denotes a plug retainer (plug member) to which a plug for sealing the gas chamber 12 is attached.

The shell 10 is formed by joining a bottom shell (shell divided body) 20 as a main body and a cap shell (shell divided body) 30 having a shorter axial length than the bottom shell 20 to form a sealed container. And each shell 20,3
“0” is a value divided in the axial direction before joining. Each of the shells 20 and 30 is formed by press-forming a substantially uniform thickness with a metal such as steel, and the body portions extending in the axial direction are joined by welding.

The bellows 40 comprises a bellows body 41 which expands and contracts in the axial direction, a bottom seal 42 fixed to one end of the bellows body 41, and a bellows cap 43 fixed to the other end of the bellows body 41. . The means for fixing the bottom seal 42 and the bellows cap 43 to the bellows body 41 is welding means such as TIG or plasma. In the bellows 40, the bottom seal 42 is fixed to the port 50 by welding, and the internal space thereof is
The space defined between the bellows 40 and the shell 10 constitutes the gas chamber 12. The oil chamber 11 is communicated with a hydraulic circuit (not shown), and the gas chamber 12 is filled with an inert gas such as nitrogen gas at a predetermined pressure. An oil port 42 a is formed at the center of the bottom seal 42, and a bellows body 4 is formed on the inner surface of the bellows cap 43.
A rubber self-seal 44 is attached to prevent excessive compression of the bellows 1 and the accompanying damage of the bellows cap 43 itself.

The port 50 has a fitting peripheral portion 51 that fits into a through hole 30 a formed at the center of the cap shell 30, and extends outwardly from the fitting peripheral portion 51 to engage with the inner surface of the cap shell 30. And an oil passage 50a communicating with the hydraulic circuit is formed at the center of the cylindrical body. The port 50 is inserted into the through hole 30 a from the inside of the cap shell 30, and connects the step 52 to the cap shell 3.
The engagement peripheral portion 51 is engaged with the through hole 30a by being engaged with the inner surface of the cap shell 30, and is fixed to the cap shell 30 by welding.

The plug retainer 60 is provided on the bottom shell 20.
Peripheral part 61 fitted in through hole 20a formed at the center of
And the bottom shell 20 extending from the fitting peripheral portion 61 to the outer diameter side.
And a cylindrical body having an annular step 62 engaged with the inner surface of the bottom shell 20 and fixed to the bottom shell 20 by welding. A gas inlet 60 a is formed at the center of the plug retainer 60, and the gas inlet 60 a
After gas is sealed in the inside, a plug (not shown) is screwed and sealed.

According to the accumulator of the present embodiment having the above configuration, the pressure of the pressure oil introduced into the oil chamber 11 from the oil passage 50a of the port 50 through the oil port 42a of the bottom seal 42 is reduced by the gas chamber 12 Exceeds the gas pressure, the bellows body 41 expands and the gas in the gas chamber 12 contracts. On the other hand, when the pressure of the pressure oil in the oil chamber 11 falls below the gas pressure in the gas chamber 12, the bellows body 41 The gas pressure in the gas chamber 12 expands due to contraction. Due to the expansion and contraction of the gas in the gas chamber 12, the pressure fluctuation of the pressure oil in the hydraulic circuit is buffered, and the pulsation of the pressure oil is suppressed.

Next, a method for manufacturing the accumulator according to the present invention will be described in the order of steps. [First Step] Attaching Bellows and Port to Cap Shell First, as shown in FIG. 1, a bellows main body 41 is welded to a bottom seal 42 constituting the bellows 40 by TIG welding, plasma welding, or the like. Next, the bottom seal 42 is welded to the port 50. As shown in FIG. 2A, an edge 45 having a substantially right-angled cross section is formed on the inner surface of the lower bent portion of the bottom seal 42 before welding. With the butted portions pressed against the port 50 side, the two are resistance welded as shown in FIG. 2 (b). Since the edge 45 is a projection, this welding is projection welding. In welding, the edge 45 of the bottom seal 42 is mainly melted and welded.

Next, the cap shell 30 and the port 50
And projection welding in the same manner. As shown in FIG. 3A, before welding, when the port 50 is inserted into the through hole 30a of the cap shell 30 from the inside, the edge 31 on the far side (upper side in FIG. 3) of the through hole 30a is 5
0 is in a state of abutting the fitting peripheral portion 51. From this state, while pressing the edge 31 to the back side, FIG.
Both are resistance-welded as shown in FIG. During welding, the edge 31 of the cap shell 30 is mainly melted and welded. Next, as shown in FIG. 1, the bellows cap 43 constituting the bellows 40 is welded to the bellows main body 41 by TIG welding, plasma welding, or the like.

[Second Step] Attachment of Plug Retainer to Bottom Shell Next, the plug retainer 60 is projection-welded to the bottom shell 20. As shown in FIG. 4A, before welding, the plug retainer 60 is connected to the bottom shell 20.
In the state inserted from the inside into the through hole 20a, the through hole 20a
The edge 21 on the back side (the lower side in FIG. 4) of the plug retainer 6
0 is in contact with the fitting peripheral portion 61. From this state, while pressing the edge 21 to the back side, FIG.
Both are resistance-welded as shown in FIG. In welding, the edge 21 of the bottom shell 20 is mainly melted and welded.

Through the above first and second steps, the bellows 40 and the port 50 are attached to the cap shell 30, and the plug retainer 60 is attached to the bottom shell 20. Next, the bottom shell 20 and the cap shell 30 are joined by projection welding.

[Third Step] Joining of Bottom Shell and Cap Shell As shown in FIG. 5, annular joints 22 and 32 projecting to the outer peripheral side are entirely formed at the joints of the shells 20 and 30. Each is formed over the circumference. These annular peripheral parts 2
2, 32 are conical portions 22a, 32a protruding at an angle of about 45 ° with respect to the axial direction, and short peripheral portions 22 extending in the axial direction from the tips of the conical portions 22a, 32a toward the joining side.
b, 32b. And each shell 2
At 0 and 30, triangular annular projections 2 tapering toward the joining side are provided at the tips of the peripheral portions 22b and 32b.
3, 33 are formed over the entire circumference.

In order to join the shells 20, 30, FIG.
As shown in FIG. 7, the two annular projections 23 and 33 abut each other, and the annular peripheral portions 22 and 32 are connected to a pair of annular electrodes 70A and 70A.
70B, and further pressurized by these electrodes 70A, 70B, the annular projections 23, 33 are strongly butted against each other.
Energize 0B and perform projection welding. At the time of welding, the annular projections 23 and 33 are melted and welded. The groove angle (the angle θ in FIG. 5) in a state where the annular protrusions 23 and 33 abut each other is about 90 °.

In the above embodiment, the port 50 and the plug retainer 60 are fixed to each of the shells 20, 30 by projection welding, and thereafter, the shells 20, 30 are joined by projection welding.
In the projection welding, since the welding is completed almost instantaneously, the accumulator can be manufactured in a very short time, and as a result, the mass productivity is improved and the cost is reduced.

By the way, projection welding cannot be performed well if there is a large difference in heat capacity between base materials to be welded. In the case of this embodiment, however, the bottom shell 20 and the cap shell 30 have almost the same thickness. Since they are uniform, their heat capacities are almost equal. Therefore, the projection welding is performed well, and the sealed state of the shell 10 becomes reliable and strong. Further, in order to make the thickness of the bottom shell 20 and the cap shell 30 substantially uniform, press forming is preferably performed without any processing such as cutting or forging, and this forming method promotes a reduction in manufacturing cost.

The port 50 is fitted into the through hole 30 a from the inside of the cap shell 30, and the annular step 52 is engaged with the inner surface of the cap shell 30. The plug retainer 60 is fitted into the through hole 60 a from the inside of the bottom shell 20, and the annular step 62 is engaged with the inner surface of the bottom shell 20. Accordingly, the movement of the port 50 and the plug retainer 60 to the outside of the shell 10 in the fitted state is restricted, and the port 50 and the plug retainer 60 are securely prevented from falling out of the shell 10. For this reason, the port 50 and the plug retainer 60 are prevented from being accidentally pulled out due to an increase in the internal pressure of the shell 10.

In the accumulator, the inside of the bellows 40 constitutes the oil chamber 11, but the manufacturing method of the present invention is applied to an accumulator in which the inside of the bellows 40 constitutes the gas chamber 12 shown in FIG. Can also be applied. In the figure, the same components as those in FIG. 1 are denoted by the same reference numerals. In this case, the bottom seal 42 of the bellows 40 is welded to the plug retainer 60, and the bottom seal 42 is formed with a gas inlet 42b. Also,
A self-seal 44 is attached to the outer surface of the bellows cap 43. The internal space of the bellows 40 constitutes the gas chamber 12, and the space defined between the bellows 40 and the shell 10 constitutes the oil chamber 11. The assembling procedure is the same as that of the above embodiment except that the bottom seal 42 is welded to the plug retainer 60 instead of welding to the port 50, and the accumulator can be manufactured by performing the welding method in the same manner.

In the accumulator of the above embodiment, the metal bellows 40 is used as a cushioning material for partitioning the inside of the shell 10 into the oil chamber 11 and the gas chamber 12, but the bellows 40 is made of a material other than metal. It may be. The cushioning material is not limited to the bellows, but may be a piston, a diaphragm, a balloon, or the like. Although the path of the pressurized oil is of a type that enters and exits the oil passage 50a of the port 50, the pressure oil has an inlet and an outlet for the oil chamber 11 separately, and the path of the pressure oil extends along the axial direction. The present invention can be applied to an in-line accumulator.

[0026]

As described above, according to the present invention, the port and the plug member are fixed to each shell divided body by resistance welding, and thereafter, the shell divided bodies are joined by resistance welding. As a result, there is an effect that the mass productivity is improved and the cost is reduced.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of an accumulator according to an embodiment of the present invention.

FIG. 2 is a longitudinal sectional view showing a step of projecting a bottom seal of a bellows and a port by projection welding;
(A) is before welding and (b) is after welding.

FIGS. 3A and 3B are longitudinal sectional views showing a step of performing projection welding of a cap shell and a port, wherein FIG. 3A shows a state before welding and FIG. 3B shows a state after welding.

FIG. 4 is a longitudinal sectional view showing a step of projecting and welding the cap shell and the plug retainer;
(A) is before welding and (b) is after welding.

FIG. 5 is a longitudinal sectional view of a joint showing a state before the bottom shell and the cap shell are subjected to projection welding.

FIG. 6 is a longitudinal sectional view showing a modified example of the accumulator according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Shell, 11 ... Oil chamber, 12 ... Gas chamber, 20 ... Bottom shell (shell split body), 30 ... Cap shell (shell split body), 40 ... Bellows (buffer material), 50 ... Port, 50a ... Communication path , 52, 62: annular stepped portion, 60: plug retainer (plug member), 60a: gas inlet.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Koji Nakamura, Inventor 3-10-10 Fukuura, Kanazawa-ku, Yokohama-shi, Kanagawa Japan F-term (reference) 3H086 AA27 AD01 AD07 AD15 AD39

Claims (3)

[Claims] 1. Inside a shell formed by joining two split shells divided in the axial direction, a cushioning material for partitioning the inside into an oil chamber communicating with a hydraulic circuit and a gas chamber filled with gas is provided. A method of manufacturing an integrated accumulator, comprising: a port formed with a communication path to the hydraulic circuit; a communication path connected to the communication path, the interior of the accumulator being partitioned into the oil chamber, and the exterior being partitioned into the gas chamber. A first step of attaching a cushioning material and fixing the port to one of the shell divisions by resistance welding, and a plug member having a gas inlet formed in the other shell division and communicating with the gas chamber. 2nd fixed by resistance welding
And a third step of joining the respective shell divided bodies to each other by resistance welding to form a shell containing the cushioning material therein. 2. Inside a shell formed by joining two axially divided shells, there is provided a cushioning material for partitioning the interior into an oil chamber communicating with a hydraulic circuit and a gas chamber filled with gas. A method for manufacturing an integrated accumulator, comprising: a first step of fixing, by resistance welding, a port having a communication passage to the hydraulic circuit to one of the shell divided bodies; and a gas communicating with the gas chamber. The plug member having the inlet formed therein is attached with the cushioning material which communicates with the gas inlet to partition the inside into the gas chamber and the outside into the oil chamber, and divides the plug into the other shell. A second step of fixing to the body by resistance welding, and a third step of joining the shell divided bodies to each other by resistance welding to form a shell containing the cushioning material therein. Accu Method for manufacturing muleta. 3. The port and the plug member are fitted from the inside of the shell divided body, and the port and the plug member are engaged with the inner surface of the shell divided body in the fitted state. The method for manufacturing an accumulator according to claim 1 or 2, wherein a step portion for restricting movement of the shell to the outside of the shell is formed.