JPH0751417Y2 - Pneumatic piston - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial field of application] The present invention relates to a pneumatic piston used for a brake valve or the like in an automobile.

[Prior Art] FIG. 3 is a side sectional view of a conventional brake valve. The operation is such that when the plunger 3 is depressed by a brake pedal (not shown), the depression causes the seat 3a and the spring 4 to intervene. , The primary piston 2 is pushed downwards so that the primary piston 2 contacts the primary valve 5 and
Push down the valve 5.

As a result, the chamber 1g communicates with the primary out 1c, and compressed air from one air tank (not shown) is passed through the primary in 1a, the chamber 1g, and the primary out 1c to the brake device on the rear wheel of the vehicle. Apply the brakes.

Furthermore, the air pressure generated in the primary out 1c
The air pressure is transmitted to the displacement chamber 1h via 1i, and the air pressure thereof pushes down the piston 6, and the depressed piston 6 pushes down the secondary valve 7 to communicate the chamber 1k with the displacement chamber 1j.

As a result, the compressed air from the other air tank (not shown) brakes the braking device at the front wheel of the vehicle through the secondary in 1b, the chamber 1k, the displacement chamber 1j and the secondary out 1d.

Further, in this case, the air pressure in the primary out 1c is transmitted to the chamber 1e through the perforations 1f and then the primary pressure is transmitted.
It acts in the direction to push back the piston 2, and as a result, the position of the primary piston 2 is set at the position where the air pressure pushing back the primary piston 2 in the chamber 1e and the biasing force of the spring 4 are balanced, and the primary piston 2 is generated in the plunger 3. Brake pressure according to pedaling force is primary out
Output to 1c and secondary out 1d.

In the above operation, when the primary out 1c side is damaged and the primary out 1c side is open to the atmosphere, the pedaling force applied to the plunger 3 is directly applied from the spring 4 and the plunger piston 2 to the piston 6 Is pushed down to open the secondary valve 7, and the compressed air from the secondary in 1b is pumped to the front wheel braking device through the chamber 1k, the displacement chamber 1j and the secondary out 1d.

When the secondary out 1d side is damaged and the secondary out 1d side is at atmospheric pressure, the primary piston 2 can open the primary valve 5 as described above. Inn 1a
Compressed air from can be pumped to the primary out 1c.

In the above brake valve, the O-rigs 6c and 6d in the piston 6 have an important role.

It is because if the O-rings 6c and 6d are damaged, if the brake system of the primary out 1c or the secondary out 1d is damaged, the undamaged side from the primary in 1a or the secondary in 1b The compressed air escapes from the O-rings 6c and 6d to the damaged side, and when the brake pedal is depressed, the compressed air cannot be sufficiently pumped to the brake device on the remaining undamaged side. Because it will be.

In order to prevent such a situation, even if either the O-ring 6c or the O-ring 6d is damaged, the damage can be checked as follows.

That is, in the state where neither side of the primary out 1c and the secondary out 1d is damaged,
When the plunger 3 is stepped on, the pushing chamber is always pushed out as described above.
Air pressure is generated at 1h and 1j. Therefore, if the O-ring 6c or 6d is damaged, the pushing chamber 1h
Alternatively, the compressed air in 1j is drilled from the damaged part of the damaged O-ring 6c or 6d through the hole 6b.
It will leak to 7b and you can check the leak.

[Problems to be Solved by the Invention] In the brake valve as described above, the piston 6
In addition, individually cutting the grooves of the O-rings 6c and 6d and the air vent groove in the middle of the grooves result in a very troublesome cutting process.

FIG. 4 is an enlarged explanatory view of the O-rings 6c and 6d in FIG. 3, and the O-rings 6c and 6d are also shown.
Shows the state where the is removed.

As can be seen from FIG. 4, O-rings 6c and 6d
In order to cut an open groove that is cut in the axial middle of the O-ring 6c and the O-ring 6d, the end faces 6f, 6h, 6k and 6g and the bottom faces 6m and 6p of the O-ring groove are to be cut.
Furthermore, regarding the open groove, the end faces 6i and 6j and the bottom face 6n thereof are
This means that the dimensional control in the cutting process of 9 positions in total must be done, which is troublesome.

An object of the present invention is to provide an inexpensive pneumatic piston for mass production, which reduces the troublesomeness of the O-ring groove processing.

[Characteristics for Solving the Problem] A single groove for burying two O-rings is formed on the outer circumference of the piston, and between the two O-rings in the axial direction,
The O-ring groove of the two O-rings is formed by interposing a ring made of a synthetic resin material that goes around the outer circumference of the piston.

Therefore, the machining of the grooves for the two O-rings on the piston is completed by a single process, and the synthetic resin ring that divides the two O-ring grooves is formed by injection molding.
It will be possible to mass-produce inexpensively in a short time.

In addition, an opening groove that opens to the atmosphere via a piston is provided in the middle of the synthetic resin material ring in the axial direction.
The ring groove is communicated with the portion on the side in contact with the synthetic resin ring.

Therefore, when both of the O-rings or any of the O-rings are damaged, the compressed air from one of the displacement chambers formed by the piston and the cylinder or the other of the displacement chambers causes the damaged portion of the damaged O-ring to be combined. It leaks out through the open groove of the resin ring and the piston, and it can be detected that any one of the O-rings is broken.

That is, when the O-ring is damaged in this way, if the operator puts his fingertip on the part open to the atmosphere from the open groove, the compressed air leaking from the part open to the atmosphere is lost. It can join the fingertip and sense the air leak at the fingertip.

If you want to detect the air leak more precisely,
When a worker applies soap water from the open groove to the portion open to the atmosphere, the leaked air causes the soap water to swell, and the swelling can detect the occurrence of the leak.

[Embodiment] The present invention will be described below based on an embodiment.

FIG. 1 is a side sectional view of the present invention in which the conventional piston 6 in FIG. 4 is improved, the drawing showing a piston portion in the same range as FIG. 4, and FIG. It is a view of arrow B of only the synthetic resin ring 8 in FIG.

In FIG. 1, a piston 16 corresponds to the piston 6 in FIG. 3, and a single groove 16a is formed on the outer circumference of the piston 16 and a synthetic resin ring 8 is formed in the groove 16a.
Is attached to form O-ring grooves 16c and 16d, and a groove 8a is formed in the synthetic resin ring 8, and the groove 8a is formed with a hole 16b.
It is in a relationship of communicating with the perforation 16e through. In addition,
The O-rings to the O-ring grooves 16c and 16d are shown in a removed state.

Further, as shown in FIG. 2, the synthetic resin ring 8 is provided with a split 8b, and when the synthetic resin ring 8 is mounted in the groove 16a, the split 8b portion is expanded and mounted.

The operation of the above configuration will be described below.

The operation of the entire brake valve is the same as that described in FIG. 3, but when machining the two O-ring grooves 16c and 16d, the dimension between the two positions of the end face 16f and the end face 16g. Control and dimension control of the bottom portion of the groove 16a are sufficient, and the end surfaces 8c and 8d on the other side of the O-ring grooves 16c and 16d are inevitably formed by mounting the synthetic resin ring 8 in the groove 16a. Will be done.

When the O-ring (not shown) in the O-ring groove 16c or the O-ring groove 16d is damaged, compressed air generated in the displacement chamber 1h or 1j when the plunger 3 is stepped on as shown in FIG. From the damaged portion of the damaged O-ring, the split gap portion of the split 8b (or the outer circumferential gap portion of the synthetic resin ring 8), the open groove 8a, the perforation 16
It will leak out to the atmosphere via b, 16e and 7b (Fig. 3), which leak is detected in the perforations 7b in Fig. 3.

Although the above embodiment has been described by taking the brake valve as an example, the O-ring groove of the piston 16 has a structure in which the O-ring for sealing is provided between the two displacement chambers formed on both sides of the piston by the piston and the cylinder. The present invention is applicable to any pneumatic piston in which the O-ring is damaged and compressed air may escape from one displacement chamber side to the other displacement chamber side.

[Effects of the Invention] As is apparent from the above description, the effects of the present invention are as follows.

1) A single groove 16a is cut on the outer circumference of the piston 16 and the groove 1
By mounting the synthetic resin ring 8 on 6a, one O-ring groove 16c and the other O-ring groove 16d are formed. It is sufficient to manage the relative dimension of the end surface 16j at two positions and the depth dimension of the groove 16a.
There is no need to manage a lot of machining dimensions such as h6i, 6j, 6k and 6g and bottom 6m, 6n and 6P at 9 positions.

2) Further, since the synthetic resin ring 8 for forming the end faces 6h and 6k in the related art can manufacture a large amount of products at a very low cost in a short time by injection molding, the groove 16a can be simply processed. At the same time, the production of the present pneumatic piston is very suitable for mass production, and the production unit price can be reduced.

[Brief description of drawings]

FIG. 1 is a side sectional view showing an embodiment of a pneumatic piston of the present invention and corresponds to an improved view of the conventional piston 6 shown in FIG. 4, and FIG. 2 is a synthetic resin ring 8 shown in FIG. FIG. 3 shows a side sectional view of a conventional brake valve, and FIG. 4 shows the O-ring 6c and 6d in FIG. FIG. 6 is an enlarged explanatory view of the vicinity of rings 6c and 6d. The symbols used in the examples are as follows. 8: synthetic resin ring, 8a: open groove, 8b: split, 16: piston, 16a: groove, 16b and 16e: drilled, 16c and 16d: O-ring groove, 16f and 16g: end face.

Claims (1)

[Scope of utility model registration request] 1. A piston that slides axially in a cylinder and the cylinder provide one displacement chamber on one side of the piston in the axial direction and the displacement of the other on the other side in the axial direction. A chamber is provided, and the outer circumference of the piston that slides in the cylinder has O
In a configuration in which two rings are arranged in the axial direction and the two O-rings are open to the atmosphere between the axial directions, the two O-rings are embedded in the outer circumference of the piston. By cutting a single groove and inserting a ring of synthetic resin material that goes around the outer circumference of the piston between the axial directions of the two O-rings, each O-ring of the two O-rings is provided. A groove is formed, and an open groove that is open to the atmosphere through the piston is provided in the axial middle of the synthetic resin material ring, and the open groove is in contact with the synthetic resin material ring of each O ring groove. Pneumatic piston characterized by communicating with the side part.