JPH068398Y2 - Hydraulic pulsation absorber - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a hydraulic pulsation absorbing device used in a hydraulic circuit, for example, a hydraulic clutch actuating device of a vehicle or the like, and in particular, a cylindrical type for absorbing vibration. The present invention relates to improvements using rubber springs.

(Prior Art) For example, Japanese Utility Model Publication No. 59-8023 shows one of hydraulic pulsation absorbing devices of this type using a rubber spring. A hydraulic pulsation absorber using a rubber spring consists of a body with a cylinder hole, a piston slidably inserted in the cylinder hole, a hydraulic chamber defined by the piston in the cylinder hole, and a hydraulic chamber of the piston. A cylindrical rubber spring for absorbing vibration arranged on the side opposite to the side, and a ring-shaped plate member arranged between the piston and the rubber spring are provided.

Such a hydraulic pressure pulsation absorbing device has advantages that it can be easily miniaturized and that an effective damping effect can be obtained regardless of the magnitude of the vibration frequency, as compared with a device using a coil spring.

(Problems to be solved by the invention) However, it has been found that when the mass of the piston is large, the vibration damping function of the rubber spring itself may be hindered. That is, it is a phenomenon in which the damping effect in the high frequency region is reduced due to the influence of the inertial force acting on the piston.

Therefore, in order to avoid such a problem, it was considered to make the piston plastic to reduce the weight.

It is an object of the present invention to provide a technique suitable for plasticizing a piston.

(Outline of Device) In this device, as shown in FIG. 1 corresponding to the embodiment,
The piston 30 is made of a synthetic resin material,
The outer cylindrical portion 32 that slides with respect to the cylinder hole, and the plate member 4
It has a double cylindrical shape having an inner cylindrical portion 31 that fits in the inner hole 42 of zero.

The double cylinder shape reduces the overall wall thickness of the piston 30, solves the problem of sink mark peculiar to the case of resin, and also ensures the mutual alignment of the rubber spring 50 and the piston 30. .

(Example) The hydraulic pulsation absorbing device 10 is connected in the middle of a pipe, for example, in the middle of a pipe connecting a clutch master cylinder and a clutch operating cylinder. Therefore, the hydraulic pulsation absorbing device 10 has two pipe connection ports. The two pipe connection ports are located on one side of the main body 12 and separated from each other by 90 °. One pipe connection port 14 is an inlet communicating with the clutch master cylinder, and the other pipe connection port (not shown) is an outlet communicating with the clutch operating cylinder.

These two pipe connection ports communicate with the small diameter hole 16 inside the main body 12. In addition to the small-diameter hole 16, a large-diameter hole 18 is formed in the main body 12 continuously from the small-diameter hole 16.
Has one end open to the other end surface of the main body 12. The small-diameter hole 16 and the large-diameter hole 18 have the same axis, and the axis is 2
It is orthogonal to each axis of one pipe connection port. A piston 30 is arranged in the small diameter hole 16, and a rubber spring 50 is arranged in the large diameter hole 18.

Here, the piston 30 is a molded product made of a synthetic resin material for weight reduction, and has a double cylindrical shape. That is, the piston 30 includes an inner cylindrical portion 31 located at the center and an outer cylindrical portion 32 that concentrically surrounds the outer side thereof.
Have and. The inner tubular portion 31 has a tapered shape, and its length is slightly longer than the outer tubular portion 32. Inner tube part 3
The end 31a of No. 1 fits in the inner hole 42 of the ring-shaped plate member 40, and the centers of the piston 30 and the plate member 40 are aligned with each other. Since the rubber spring 50 is integrated with one surface of the plate member 40 by baking or the like, as a result, the piston 30 and the rubber spring 50 are aligned with each other.

The outer periphery of the outer tubular portion 32 of the piston 30 has a small diameter hole 1
It fits in 6 and can be moved in the left-right direction in the drawing. The outer diameter of the piston 30 itself is large, but the outer cylindrical portion 32
Since the inner thickness is not so large, there is no problem of sink marks during molding, and the outer circumference of the outer tubular portion 32 is a very smooth surface. The piston 30 also has a step portion 33 for mounting the sealing material 44 in a portion adjacent to the outer tubular portion 32. The seal member 44 defines a hydraulic chamber 60 at the bottom of the small-diameter hole 16 while preventing the seal member 44 from coming off by a member 46 that also serves as a spring receiver. It goes without saying that the hydraulic chamber 60 communicates with two pipe connection ports including the inlet 14. In the hydraulic chamber 60, that is, at the left end of the piston 30, a weak spring 48 is provided between the spring receiving member 46 and the bottom wall of the small diameter hole 16.
Is provided. The spring 48 pushes the piston 30 toward the large diameter hole 18, and the right end surface of the outer tubular portion 32 of the piston 30 is brought into contact with the plate member 40 at the bottom of the large diameter hole 18.

The rubber spring 50 has a cylindrical shape, and its outer diameter is larger than that of the small diameter hole 16 and smaller than that of the large diameter hole 18.
The rubber spring 50 is sandwiched between the plate member 40 and the piece 70 a of the bracket 70 in the large diameter hole 18. The bracket 70 is an L-shaped metal fitting, and the mounting hole 7 of the hydraulic pulsation absorbing device 10 itself is provided on one piece 70b.
2 and there are several bolts 74 on the side of the other piece 70a.
The main body 12 is fixed by. In this case, the resin sheet 76 is sandwiched between the portion where the main body 12 and the piece 70a of the bracket 70 come into contact with each other, in order to waterproof and block the outside air.

In the hydraulic pulsation absorbing device 10 described above, since the piston 30 is made of a synthetic resin material and is lightweight, even if the piston 30 moves to the left or right when absorbing vibration, the inertial force acting on it is small. . Therefore, the hydraulic pulsation absorber 10 effectively absorbs the pulsation without damaging the damping effect in the high frequency region due to the influence of the inertial force. Further, since the inner cylindrical portion 31 of the piston 30 aligns with the rubber spring 50, the piston 30 and the rubber spring 50 are reliably aligned with each other, and the pulsation can always be effectively absorbed.

The present invention is particularly effective when applied to a hydraulic circuit in which vibration in a high frequency region poses a problem. However, the present invention can be widely applied not only as a clutch damper but also for preventing pulsation on the outlet side in a plunger type pump.

(Effect of the Invention) In the present invention, by making the piston 30 plastic to reduce the weight, it is possible to obtain a sufficient damping effect in the high frequency region, and the piston 30 has a double cylindrical shape. The sink mark problem at the time of molding can be solved, and moreover, the mutual alignment of the rubber spring 50 and the piston 30 can be ensured.

[Brief description of drawings]

FIG. 1 is a sectional structural view showing an embodiment of the present invention. 10 ... Hydraulic pulsation absorbing device, 12 ... Main body, 16 ... Small diameter hole (cylinder hole), 30 ... Piston, 31 ... Inner tubular portion, 32 ... Outer tubular portion, 40 ... Plate member, 50 ...... Rubber spring, 60 ...... hydraulic chamber.

Claims (1)

[Scope of utility model registration request] 1. A body having a cylinder hole, a piston slidably inserted into the cylinder hole, a hydraulic chamber defined by the piston in the cylinder hole, and a piston chamber disposed on the opposite side of the hydraulic chamber side. In a hydraulic pulsation absorbing device including a cylindrical rubber spring for absorbing vibration, and a ring-shaped plate member arranged between the piston and the rubber spring,
While making the piston from a synthetic resin material,
A double cylinder-shaped hydraulic pulsation absorbing device having an outer cylindrical portion that slides with respect to a cylinder hole and an inner cylindrical portion that fits in the inner hole of the plate member.