JPH0648001B2 - Aki Yum Reta - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to an accumulator for interposing in an oil supply piping system of a hydraulically operated device to fulfill the role of accumulating pressure or absorbing pulsation of hydraulic pressure.

[Prior Art] As an accumulator that can be installed in a pressurized fluid piping system to store the fluid pressure and release the stored pressure all at once if necessary, the fluid pressure and the spring pressing force are used. A spring type in which the amount of accumulated pressure is determined by the balance between and is generally widely used.

FIG. 1 is a side sectional view of an accumulator according to the present invention, FIG. 2 is a partially enlarged view of the structure of a spring type accumulator, and FIG. 4 is an explanatory view of a piston shape of a conventional spring type accumulator. Explaining with reference to the drawings, a pressure accumulating chamber 3 having a pressurizing fluid inlet / outlet port 4 is formed in a space surrounded by an inner wall surface of a cylinder 2 and a front end surface of a piston 1. 6 is the piston 1
Is a piston rod for pressing the rod, and pressing rod spun rings 7 and 8 are externally fitted to the rod 6,
The rod 6 and the springs 7, 8 are housed in a jacket tube 9. The conventional piston 30 is composed of a simple columnar body as shown in FIG. 4, and the tip of the piston rod 6 on the pressing side is brought into contact with the rear surface b of the piston 30. 5 is a Pistonton ring.

A major drawback of the conventional accumulator having the above structure will be described with reference to FIGS. 1 and 4. A clearance is provided between the outer jacket tube 9 and the spring 7 to allow smooth expansion and contraction of the spring. As a result, the piston rod 6 is slightly inclined in the axial direction, and this inclination causes the front end of the piston rod 6 to deflect the force pushing the rear surface of the piston 30 as shown by the arrow F in FIG. 30 is in the cylinder 2 and receives a bending moment due to the force G as a component force of this deflected pressing force F, and as a result, the upper portion 5a of the piston ring 5 is relieved of the compression force and the lower portion 5b.
On the contrary, a situation in which a strong compressive force is applied to the piston ring 5 is brought about, and in the end, the piston ring 5 is subjected to a significant eccentric load in its diametrical direction, so that it is uneven in the circumferential direction. It was that the sealing function was likely to be lost early due to wear.

Another difficulty is that since the outer tube 9 of the accumulator is made of aluminum or the like for the purpose of weight reduction, the inner surface of the outer tube is covered with the spring 7 as the spring 7 expands and contracts.
It was worn out by the contact frictional force with and it was easy to promote the above-mentioned inconvenient phenomenon.

[Problems to be Solved by the Invention] The accumulator of the present invention has a drawback of the spring type accumulator as described in the section of the prior art, that is, when the built-in spring bends due to its own weight or the like, the piston rod is also tilted, Also, the first object is to solve the problem that the airtightness in the pressure accumulating chamber is lost as a result of the offset wear of the piston ring due to the asymmetric load applied to the piston ring in the diametrical direction. A second object is to suppress the progress of wear of the outer tube due to the contact between the tube and the spring fitted on the rod, and to eliminate the inconvenience that the inner volume of the accumulator changes due to the tilting of the piston rod. Is an incidental purpose.

[Means for Solving Problems] An accumulator according to the first invention of the present application is a bottomed cylindrical piston, a bottomed cylinder slidably supporting the piston, and an inlet / outlet port for communicating the inside and outside of the cylinder. And a piston rod having a front end portion arranged at one end in a cylindrical hole of the piston and a spring for urging the piston rod toward the piston side, and the piston has a bottom outer wall that is the cylinder. Is arranged so as to face the bottom inner wall of the, the inlet / outlet port communicates with the outside and a pressure accumulating chamber formed between the bottom outer wall of the piston and the bottom inner wall of the cylinder, and the piston rod, The front end of the front end contacts the inner wall of the bottom of the piston by the urging force of the spring, and urges the piston toward the cylinder. The internal volume of the accumulator is determined by the balance between the pressure of the fluid that flows into the cylinder through the inlet / outlet port and biases the piston in the direction opposite to the biasing direction of the spring and the biasing force of the spring. To be done.

An accumulator according to a second invention of the present application is a bottomed cylindrical piston, a bottomed cylinder that slidably holds the piston, an inlet / outlet port that communicates the inside and outside of the cylinder, and a cylindrical hole of the piston at one end. A piston rod having a front end portion disposed therein, a spring for biasing the piston rod toward the piston side, the piston,
An outer tube for accommodating a cylinder, a piston rod, and a spring, and an abrasion-resistant lining material layer for covering a wall surface of the outer tube facing the outer periphery of the spring are provided, and the piston has a bottom outer wall having a bottom outer wall of the cylinder. The inlet / outlet port communicates with a pressure accumulation chamber formed between the bottom outer wall of the piston and the bottom inner wall of the cylinder, and the outside, and the piston rod includes the spring. The front end tip abuts the bottom inner wall of the piston by the urging force of the piston to urge the piston toward the cylinder side, flows into the cylinder through the inlet / outlet port, and causes the piston to move toward the spring. The content of the pressure accumulating chamber is determined by the balance between the pressure of the fluid urged in the direction opposite to the urging direction and the urging force of the spring. There are determined.

[Advantageous Effects of the Invention] In the accumulator of the present invention, in the spring type accumulator, the tip of the piston rod is slidably fitted into the cylindrical hole provided in the back of the piston, so that the back of the piston is It is possible to bring the front end face of the piston rod to press close to the mounting position of the piston ring, and even if the piston rod is tilted due to the weight of the spring externally fitted to this rod, etc. It is possible to minimize the generation of a bending moment in the piston by the rod, and solve the problem of airtightness deterioration in the pressure accumulating chamber due to uneven wear of the piston ring. Further, since the wear resistant lining material layer is provided on the outer tube of the piston rod, the wear progress of the outer tube due to the contact between the outer tube fitted to the piston rod and the outer tube can be suppressed, and the above-mentioned piston rod It is possible to prevent the inclination from increasing and improve the durability of the accumulator.

[Embodiment] An accumulator of the present invention will be described below based on an embodiment shown in the accompanying drawings.

In FIG. 1 as a side sectional view of an accumulator of the present invention and FIG. 2 as an enlarged view of a piston portion thereof,
Reference numeral 1 is a piston, 1a is a cylindrical hole provided on the back surface of the piston 1, 1b is a bottom surface of the cylindrical hole 1a, and 5 is a piston ring. Reference numeral 2 is a cylinder, 3 is a pressure accumulating chamber formed in the cylinder, and is provided with a pressure fluid inlet / outlet port 4. A piston rod 6 has a front end portion (right side in the figure) 6a whose outer diameter is smaller than the inner diameter of a cylindrical hole 1a provided in the piston 1 and is fitted in the cylindrical hole 1a. The piston rod 6 is covered with an outer tube 9, a front end portion of the outer tube 9 is externally fitted and fixed to the cylinder 2, and a plug body 10 is screwed to a rear end portion. Further, a flange-shaped portion 6c is formed in the front portion of the piston rod 6, and a pair of strong and weak extension springs 7 and 8 are provided so as to be fitted onto the piston rod 6 between the flange-shaped portion 6c and the plug body 10. Is fitted. 1
Reference numeral 2'denotes a holder for holding the bush 12, and the spring 7 is positioned by its outer diameter portion.

11 is a bolt screwed to the rear end of the piston rod 6,
The rear end 11a of the bolt 11 and the bottom surface 10b of the inner cylindrical portion of the plug 10.
The maximum pressure accumulation amount of the pressure accumulating chamber 3 is determined by the contact of the contact points. Further, the bolt 11, the piston rod 6, the spring 8, the holder 12 'and the bush 12 are integrated in advance to facilitate the assembling to the accumulator. 12 is a bush that supports the rear end of the piston rod 6 to prevent the piston rod 6 from tilting and to position the spring 8 in the forward direction, and at least to the rear end of the piston rod 6 that slides on the bush 12. The spring 8 is prevented from coming into contact with the portion. The bush 12 is made of a bearing material such as phosphor bronze in order to prevent seizure during sliding. 13 is a wear-resistant lining material layer on the inner surface of the outer tube 9, 14 to 17 are sealing rings, and 16 is a grease filled in the contact portion between the front end portion 6a of the piston rod 6 and the bottom surface 1b of the piston 1. Prevents outflow.

Further, FIG. 3 shows a cylindrical hole provided on the back surface of the piston 1.
FIG. 3 is an enlarged side sectional view of a surface shape of a bottom surface 1b of 1a.

5 and 6 are a side sectional view and a perspective view of the wear-resistant lining material layer 13 of an example in which a wear-resistant lining material layer is provided on the inner surface of the outer tube 9 of the accumulator of the present invention.

Next, the operational features of the accumulator of the present invention over conventional accumulators of the same structure will be described.
As shown in the drawing and FIG. 2 as a partially enlarged view thereof, the piston 1 is provided with a cylindrical hole 1a on the back surface thereof having a depth reaching the vicinity of a mounting position of the piston ring 5 fitted to the outside of the piston. Provided and front end 6a of piston rod 6
Is loosely fitted in the cylindrical hole 1a, and its tip surface 6b is in contact with the bottom surface 1b of the cylindrical hole 1a. As a result, the piston rod 6 tilts due to the existence of the clearance between the spring 7 fitted on the piston rod and the outer tube 9, and the pressing force on the piston 1 is indicated by the arrow F as shown in FIG. Even if it is deflected as described above, the surface 1b on which the deflected pressing force F is exerted on the piston and the bearing point of the piston 1 in the cylinder 2, in this case, the mounting position of the piston ring 5 are , The piston 1 exists on the same vertical plane with respect to the direction in which the force F is applied, and there is no room for applying a bending moment as a component of the force F to the piston 1. Therefore, there is no cause for uneven wear of the piston ring due to the component force of the force F such as the accumulator having the conventional structure shown in FIG. However, even if the mounting position of the piston ring 5 is not exactly on the same surface as the bottom surface 1b of the piston and the cylindrical hole, as long as they are in close proximity to each other, the above bending moment is minimized. You can stay. In addition, if the bottom surface 1b remains in the cylinder 2 even when the piston 1 reaches the bottom dead center, the uneven wear of the piston ring 5 can be suppressed sufficiently low.

Next, the features relating to the surface shape of the bottom surface 1b of the cylindrical hole of the piston 1 and the shape of the tip surface 6b of the piston rod 6 that abuts on this surface will be described with reference to FIG. The rod 6 has a slightly larger radius of curvature R1 than the radius of curvature R2 of the tip end surface of the rod 6, and thus has a strength capable of reliably holding a large load of the springs 7 and 8.

Next, the function of the wear-resistant lining material, which is another component of the accumulator according to the present invention, will be described with reference to FIGS. 5 and 6.
Explaining with reference to the drawings, the inner surface of the outer tube 9 is a spring that is fitted onto the piston rod 6 and that biases the piston rod 6 so that the piston 1 always moves toward the top dead center side. 7 (and 8) is subjected to the wear acting force by continuously moving back and forth with the fluctuation of the fluid pressure applied to the pressure accumulating chamber 3. If the inner diameter of the mantle tube 9 increases due to wear, the clearance between the spring 7 and the inner surface of the mantle tube 9 described above gradually expands. Therefore, due to the reasons described above, the uneven wear of the piston ring 5 progresses. Not only is it accelerated and the life of the accumulator is shortened by that amount, but in the worst case, an unexpected situation may occur due to a sudden stop of supply of fluid pressure. This tendency is further promoted because the outer tube 9 is generally made of aluminum, synthetic resin or the like in order to reduce the weight of the accumulator incorporated in the automobile playing system. Therefore, in the accumulator of the present invention, the wear-resistant lining material layer 13 made of a material having higher wear resistance than the material of the outer tube is formed on the inner surface of the outer tube 9.

A sixth example of the material shape of the wear resistant lining material layer 13
As shown in the figure, a thin stainless steel plate rolled into a cylindrical shape can be used. An outwardly extending collar-shaped portion formed at the rear end of the wear-resistant lining material layer 13.
13a is because the presence of the cylinder end face does not give resistance when the spring 7 moves back and forth, and the inner narrowed flange-like portion 13b and the slit 13c in the cylinder length direction cover the wear-resistant lining material layer 13 with the outer tube. It is for making it easy to fit in 9. As the material of the wear resistant lining material layer 13, various engine nearing plastics having high hardness and low frictional resistance, such as nylon, polyacetal or Teflon resin, may be selected. Further, the wear-resistant lining material layer 13 is formed in advance in a cylindrical shape by using the outer tube 9
Instead of being inserted into the outer tube 9, a synthetic resin layer having excellent wear resistance may be directly formed on the inner surface of the outer tube 9 by a coating method or the like.

As an application example of the accumulator of the present invention having the structure and features as described above, when the anti-skid device of an automobile, that is, the pressure accumulating mechanism of the automatic preventive device for the wheel lock that occurs during sudden braking, is adopted, the operation mechanism is the anti-skid device. This will be described below with reference to FIG. 7 as an operation system diagram of the apparatus.

In FIG. 7, 60 is a brake petal, 61 is a master cylinder that generates fluid pressure according to the pedaling force,
62 and 63 are solenoid valves for controlling the supply of fluid pressure to the first and second wheels W1 and W2, respectively, and 64 and 65 are W1 and W, respectively.
2 braking wheel cylinders, 101 hydraulic pump, 1
00 is the accumulator according to the present invention, 102 is a fluid flow path switching valve provided to eliminate the discomfort of kickback when the pedal is depressed, 104 is the number of rotations of the wheels W1 and W2, and vehicle speed sensors D1 and D2. Control unit for operating solenoids of supply control solenoid valves 62 and 63 to prevent skid phenomenon based on information, 103
Is a reservoir and 80 and 81 are check valves.

Explaining how the anti-skid system with the above structure operates, the brake pedal while the vehicle is running.
When you depress 60, as long as the amount of depression is within the range of the appropriate value corresponding to the traveling speed, master cylinder 61
The brake fluid supplied from 70 → 71 → 72 → 73 and 70 →
The pipes 71, 74, and 75 are fed into the wheel cylinders 64 and 65 through the pipe lines, and the wheels W1 and W2 are braked to an appropriate degree that does not cause the rotation lock of the wheels.

If the driver of the vehicle finds an obstacle in the front and depresses the brake pedal 60 excessively, the brake fluid pressure rises sharply, and the functions of the wheel cylinders 64 and 65 work excessively to lock the wheels. The control unit 104 judges that the state is approaching, based on the information from the vehicle speed sensors D1 and D2 and the wheel rotation speed, and issues the solenoid operation signals for the supply control solenoid valves 62 and 63. As a result, master cylinder 61 and wheel cylinder 64 and
The state of communication with 65 is cut off by the line switching operation by the supply control solenoid valves 62 and 63, and the brake fluid in the wheel cylinders 64 and 65 follows the paths of 73 → 76 and 75 → 77 and flows into the reservoir 103. To do. On the other hand, the control unit 104 is provided with a circuit for notifying the hydraulic pressure supply valve control valve of the prediction of the occurrence of skid and at the same time issuing a start instruction to the hydraulic pump 101. Is sucked in and fed into the accumulator 100 to be stored, the hydraulic pressure in the wheel cylinder is lowered, the excessive braking of the wheel is released, and the occurrence of skid can be prevented in advance. When the braking of the wheels is restored to the moderate state, the control unit 104
This is transmitted to the solenoid valves 62 and 63 for supply control, and the valve body is switched to the neutral position so that the pipes 72 to 73 to 76 and the pipes 74 to 75 are
Since the communication between ~ 77 is cut off, the brake fluid is prevented from flowing into and out of the wheel cylinders 64 and 65, and a constant pressure is maintained.

Next, when the braking state of the wheels weakens to a certain level or less, the control unit 104 informs the supply control solenoid valves 62 and 63 of this and reconnects the pipelines 72 to 73 and the pipelines 74 to 75. The hydraulic pressure stored in the wheel cylinders is applied to the wheel cylinders 64 and 65, and the braking force increases again. Therefore, if the risk of skid occurs again, the control valve switching operation as described above is repeated.

When the vehicle is decelerated to the desired vehicle speed, the brake fluid in the wheel cylinders 64 and 65 can be returned to the master cylinder 61 by releasing the depression force of the brake pedal 60.
The master cylinder side of the check valves 80 and 81, which are interposed in the cylinders 79 and 79, respectively, have a low pressure, and the brake fluid in the wheel cylinders 64 and 65 is returned to the master cylinder 61 via these valves.

In addition, the hydraulic pressure of the brake fluid pressurized by the operation of the hydraulic pump 101 pushes the ball valve in the flow path switching valve 102 to the right in the figure to connect the accumulator 100 and the master cylinder 61 with the conduits 82 to 71. .About.70 are cut off, which makes it possible to eliminate the uncomfortable stepping comfort called the so-called kickback phenomenon due to the above-mentioned pressurized brake fluid pressure exerted on the brake pedal 60.
An accumulator having an extremely high operational reliability is required for such a device in terms of traveling safety of the vehicle, but the product of the present invention can sufficiently meet the demand.

[Brief description of drawings]

1 and 2 are a side sectional view and a partially enlarged view of an accumulator according to the present invention, and FIG. 3 is a partially enlarged side sectional view for explaining the bottom shape of a cylindrical hole provided on the back surface of a piston. FIG. 4 is a partial side sectional view for explaining the piston shape of a conventional accumulator, and FIGS. 5 and 6 are side sectional views of the accumulator in which a wear-resistant lining material layer is provided on the inner surface of the outer tube, and the lining. FIG. 7 is a perspective view of the material, and FIG. 7 is an operation system diagram of an automobile antiskid device incorporating the accumulator of the present invention. In the figure, 1 ... Piston, 1a ... Cylindrical hole, 1b ... Bottom of cylindrical hole, 2 ... Cylinder, 3 ... Accumulation chamber, 5 ... Piston ring, 6 ... Piston rod, 6b ... Piston Rod tip surface, 7, 8 ... Spring, 9 ... Outer tube,
13 ... Wear resistant lining material layer

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Hiromi Otsuki 1-1, Showa-machi, Kariya city, Aichi prefecture, Nihon Denso Co., Ltd. (72) Inventor Shinsuke Nakanishi 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Automobile Co., Ltd. (56) References Details attached to the application for Japanese Patent Application No. 53-150764 (No. 55-66203) A micro film (JP, U) that captures the contents of the calligraphy and drawings

Claims (4)

[Claims] 1. A bottomed cylindrical piston, a bottomed cylinder slidably supporting the piston, an inlet / outlet port for communicating the inside and outside of the cylinder, and an end located in a cylindrical hole of the piston. A piston rod having a front end portion and a spring for urging the piston rod toward the piston side, and the piston is arranged such that its bottom outer wall faces the bottom inner wall of the cylinder. The port communicates with the outside and a pressure accumulating chamber formed between the bottom outer wall of the piston and the bottom inner wall of the cylinder, and the piston rod has the front end tip of the piston that is urged by the urging force of the spring. It abuts the inner wall of the bottom part and urges the piston toward the cylinder side, flows into the cylinder through the inlet / outlet port, and The balance of the biasing force of tons of pressure fluid for urging in a direction opposite to the biasing direction of the spring the spring accumulator internal volume of the accumulation chamber is determined. 2. Close to the inner wall position of the bottom of the piston,
The accumulator according to claim 1, wherein a piston ring is attached to the outer circumference of the piston. 3. The piston according to claim 1, wherein an inner wall of the bottom portion of the piston has a spherical concave surface shape, and a front end of the piston rod has a spherical convex surface shape. Accumulator described. 4. A bottomed cylindrical piston, a bottomed cylinder for slidably holding the piston, an inlet / outlet port for communicating the inside and the outside of the cylinder, and one end arranged in a cylindrical hole of the piston. A piston rod having a front end portion, a spring for urging the piston rod toward the piston side, an outer tube for accommodating the piston, the cylinder, the piston rod and the spring, and the outer tube, which faces the outer circumference of the spring. A wear-resistant lining material layer covering the wall surface, the piston is arranged such that its bottom outer wall faces the bottom inner wall of the cylinder, and the inlet / outlet port is the bottom outer wall of the piston and the bottom of the cylinder. An accumulator formed between the inner wall and the outside is in communication with each other, and the piston rod is driven by the urging force of the spring. The front end tip contacts the bottom inner wall of the piston to urge the piston toward the cylinder side, flows into the cylinder through the inlet / outlet port, and pushes the piston in the urging direction of the spring. An accumulator in which the internal volume of the pressure accumulating chamber is determined by the balance between the pressure of the fluid biased in the opposite direction and the biasing force of the spring.