JPS5850086Y2 - hydraulic cylinder - Google Patents

Description

[Detailed description of the invention] This invention relates to a swing-type hydraulic cylinder used for driving mechanical chucks and tightening devices attached to the spindle of machine tools. This relates to a hydraulic cylinder with a check valve that prevents the piston from moving even if the pressure drops.

Conventionally, this type of hydraulic cylinder operating device has been designed to connect a pilot check pulp in the middle of the supply oil piping to the hydraulic cylinder to prevent the supply oil from flowing backwards, or to prevent the supply oil from flowing backwards. In the middle or distributor (
It is known that an accumulator is connected to a distributor to prevent the pressure of supplied oil from becoming abnormally high.

However, in such a device, there are no connections between the cylinder body and the distributor, the connection between the cylinder body and the piping, the connection between the pilot check valve and the piping, and the connection between the accumulator and the piping or the distributor. Even if equipped with pilot check valves and accumulators, these initial objectives cannot be achieved, as the piston may move when the pressure of the hydraulic power source decreases, causing some oil leakage from the When used to operate a chuck, there is a problem that the workpiece may come off the chuck and cause an unexpected major accident.Also, accidents like the one described above can occur due to a problem caused by the problem between the pilot check valve and the cylinder body. Problems may also occur if the piping is damaged, so the purpose of this invention is to solve the above-mentioned problems. Even if oil leaks from between the cylinder and the distributor, or if the piping to the cylinder body is damaged, the inside of the cylinder body is designed to reliably prevent the oil supplied in the cylinder chamber from leaking to the outside. Even if a check valve is installed in the middle of the oil supply and drain path to reliably prevent the supply oil from leaking into the cylinder chamber, the pressure inside the cylinder chamber will increase when the oil expands due to temperature rise. The object of the present invention is to provide a swing type hydraulic cylinder in which a relief valve or an accumulator is provided within the cylinder body or piston so as to prevent the pressure from becoming abnormally high.

Next, embodiments of the present application will be described in detail with reference to the drawings.

Fig. 1 shows an embodiment in which the present invention is applied to a rotating hydraulic cylinder for a chuck.The cylinder main body A is composed of a cylinder tube 1, a rad cover 2 and a rod cover 3. The distributor 4 is attached to the shaft portion 2a of the rad cover 2 to the cylinder.
They are fitted to allow rotation of a.

A sliding hole 6 is provided in the piston 5 of the hydraulic cylinder,
Further, an intermediate chamber 8 communicating with the sliding hole is formed in the rond part T of the piston 5, and a conductive shaft 9 in which a part of the rod cover 2 is protruded from the cylinder toward the rod cover 3 is connected to the sliding hole of the piston 5. The hole 6Vc is slidably fitted, and the tip of the conduction shaft 9 faces the intermediate chamber 8.

The middle chamber 8 communicates with the cylinder chamber 11aK on the right side in FIG. 1 through a communication hole 10.

12 is an oil supply/drain passage for supplying and discharging oil to the cylinder chamber 11b on the left side in FIG. 1, and is provided in the rad cover 2 to the cylinder, and 13 is an oil supply/drain passage for supplying and discharging oil to the cylinder chamber 11a on the right side. The conductive shaft 9 is provided in the radial cover 2 to the cylinder at the tip of the conductive shaft 9.

These oil supply and discharge passages 12 and 13 communicate with ports 14 and 15 provided in the distributor 4, respectively, and from these ports 14 and 15 pressure oil is supplied to the left and right cylinder chambers 11a and 11b, and the cylinder chambers are The oil is discharged from 11at11b.

A valve chamber 16, which is exemplified as a non-sliding chamber, is provided in the middle of the oil supply/drainage path 12° 130 in a direction perpendicular to the axis of rotation.

Inside this valve chamber 16 is a valve body 17, which is illustrated as a non-sliding body.
a is fitted so as to be slidable by a predetermined amount in the vertical direction in FIG. By supplying oil to the oil supply/drainage path 13, it is slid toward the other end (the upper end in FIG. 1).

Inside the valve body 17a, as shown in FIG. Outflow holes 22, 23 are provided which communicate with and open to the circumferential surface.

The inflow holes 20 and 21 communicate with the ports 14 and 15, respectively, and the outflow holes 22 and 23 communicate with the left and right cylinders x11b.
.

11a, respectively.

Poppets 24 and 25 are slidably fitted into the respective valve holes 18 and 19, and sealed springs 26 and 27 close the valve portion 24b.

25b are crimped to the seat surfaces 28 and 29, respectively, and the check valves 1
7.

The legs 24a and 25a of these poppets 24 and 25 are fitted into the respective inflow holes 20 and 21 with plenty of room, and part of them protrudes slightly from the end surface of the valve body 17a, with one end of the valve body 17a. When slid to the side, the legs 24a and 25a of the poppets 24 and 25 come into contact with the inner wall of the valve chamber 16 and are pushed up against the springs 26 and 27, thereby opening the valve and opening the inflow hole 2G, 21 and outflow holes 22 and 23 are configured to communicate with each other.

Next, the cylinder chambers 11b for 30 and 3h. This is a relief valve for preventing the pressure of the oil sealed in 11a from becoming abnormally high, and is provided in the piston 5 in this embodiment.

These relief valves 30 and 31 have the same configuration except that the direction is changed by 180 degrees, and the valve body 30a is fitted onto the piston 5.

31a, valve bodies 30b, 31b fitted so as to be freely inserted into the valve bodies 30a, 31a, and springs 30c, 31c, etc. that bias the valve bodies 30b, 31b, and when one acts as a relief valve, the other acts as a check valve. It is designed to work as a valve.

Springs 30c, 31 of these relief valves 30, 31
The elasticity of c is preset to an appropriate value so that when the pressure in the cylinder chambers 11a, 11b exceeds an abnormally high predetermined pressure, the valves are compressed and opened.

In the above structure, when pressure oil is supplied from the port 14 by a hydraulic source (not shown), the pressure oil is supplied to the valve body 17.
A is slid downward in FIG. 1 until it comes into contact with the inner wall of the valve chamber 16, and at the same time the poppet 24 is pushed down against the spring 26, whereby the pressure oil passes through the outflow hole 22 and flows into the left cylinder. Enter room 11b.

On the other hand, when the valve body 17a is slid downward as described above, the leg portion 25a of the poppet 25 protrudes beyond the end surface of the valve body 17a, so the inner wall of the valve chamber 16 touches the leg portion 25a of the poppet 25. It is pushed up against the spring 27 to release the pressure of the valve portion 25b from the seat surface 29 and open the valve.

Therefore, the oil in the right cylinder chamber 1a is contained in the check valve 1T.
can return to the port 15 through the outflow hole 23 and inflow hole 21, the piston 5 is slid to the right, and the rod portion 7 of the piston 5 is located at the most extreme position.

Then, when the movement of the piston 5 is stopped as described above,
The poppet 24 of the check valve 1T is slid upward by the elastic force of the spring 26, and the valve portion 24b is pressed against the seat surface 28 to prevent leakage.

As mentioned above, since the valve part 24b is crimped to the seat surface 28 to prevent leakage, even if the oil supplied from the port 14 drops in pressure for some reason, the cylinder chamber 1ib
The pressure oil inside does not flow backward, maintains the initial predetermined pressure, and continues to reliably position the piston 5 and the rod portion 7 of the piston 5 at the most extreme position.

In addition, since the relief valve 30 is provided in the piston 5, the temperature of the entire hydraulic cylinder increases with pressure oil sealed in the cylinder chamber 1ib as described above, and the temperature of the cylinder body A and the oil increase. Even if the pressure of the oil in the cylinder chamber 11b starts to rise due to the difference in the coefficient of thermal expansion of
The pressure of the oil in the cylinder chamber 11b does not become abnormally high due to the oil leaking into the cylinder chamber 11b.

. Next, when the piston 5 is to be slid to the left in FIG. 1, it is preferable to switch the switching valve (not shown) and supply pressure oil from the port 15.

That is, when pressure oil is supplied from the port 15, this pressure oil causes the valve body 17a of the check valve 1T to slide upward and come into contact with the inner wall of the valve chamber 16, thereby causing the poppet 24 to resist the spring 26. The oil in the cylinder chamber 11b is pushed down and allowed to flow back, and at the same time the pressure oil pushes the poppet 25 upward against the spring 27 and enters the cylinder chamber 1a, causing the piston 5 to slide to the left.

When the leftward movement of the piston 5 is stopped, the valve portion 25b of the poppet 25 of the check valve 17 is pressed against the seat surface 29.

Therefore, in this case as well, the piston 5 is reliably held at its original position even if the pressure of the supplied oil decreases due to an oil leak in the middle of the piping or the like.

Further, even if the temperature of the hydraulic cylinder increases, the pressure of the oil in the cylinder chamber 1a will not become abnormally high due to the action of the relief valve 31.

FIG. 3 shows a different embodiment of the present application, in which relief valves 30e and 31e similar to those in the above embodiment are provided in the cylinder of the cylinder body Ae, in parallel with the check valve 17e, in the rad cover 2e. , one relief valve 30e is connected to the rear cylinder chamber and the oil supply/discharge passage 13.
e through oil passages 32 and 33, respectively, and the other relief valve 31e is connected to the front cylinder chamber and the oil supply/discharge passage 12e.
The two are connected through oil passages 34 and 35.

This embodiment is not limited by the size of the piston and can be easily implemented even in extremely small hydraulic cylinders.

It should be noted that parts that are considered to have the same or equivalent configuration as those of the above-mentioned embodiments are given the same reference numerals as corresponding parts with the letter "e", and a detailed description thereof will be omitted.

(Also, in the next example, the alphabet f
is added to omit duplicate explanation.

) FIG. 4 shows another different embodiment, in which an accumulator 36 is provided in the piston 5f instead of the relief valve of the above embodiment.

This accumulator 36 has a hole 3T provided with a piston 5fK.
A pair of sub-pistons 38 and 39 are slidably fitted in the inside, and a spring 40 is enclosed between these sub-pistons 38 and 39, and snap rings 41 and 42 are used to prevent the sub-pistons 3B and 39 from coming out. It is configured with a stop.

Therefore, when the oil pressure in the rear cylinder chamber 11bf increases, the sub-piston 38 slides to the right against the spring 40, thereby preventing the pressure in the cylinder chamber 11bf from becoming abnormally high.

Further, when the pressure of the oil in the cylinder chamber 11bf decreases due to a drop in temperature, the sub-piston 38 slides to the left, and the pressure in the cylinder chamber 11bf is maintained.

The same thing can be said when oil is sealed in the cylinder chamber 11af.

Incidentally, the accumulator may be provided within the cylinder body instead of being provided within the piston 5f, or the accumulator may be provided within the cylinder chamber 1.
It may be provided separately for 1af and cylinder chamber 11bf.

The present application is not limited to the above embodiments, and the configurations of the check valve, relief valve, or accumulator may be changed as appropriate.

For example, two valve sliding chambers and a valve sliding body formed by dividing the valve chamber and valve body of the first embodiment at the center are provided in two supply and discharge passages, and one supply and discharge passage is provided with oil supply. An oil passage may be provided so that when the valve is supplied, the valve sliding body on the supply side is slid to open the valve hole, and the non-sliding body on the return side is slid to open the valve hole.

Further, a check valve, a relief valve, etc. may be oriented parallel to the axis of the hydraulic cylinder.

As described above, in the present invention, a check valve is provided in the middle of the oil supply and drainage path within the cylinder body, so that when the pressure of the hydraulic source decreases, the check valve is installed between the cylinder body and the distributor or to the hydraulic cylinder. Even if oil leaks in the middle of the piping or the piping to the cylinder body is damaged, the oil sealed in the cylinder chamber can be reliably prevented from flowing backwards, ensuring that the piston returns to its original operating position. When used to operate the claws of a rotating chuck, accidents such as the workpiece coming off from the chuck can be reliably prevented.

In addition, even if a check valve is installed in the oil supply and drainage passage within the cylinder body to prevent the oil from flowing backwards in the cylinder chamber, the pressure of the oil in the cylinder chamber may become abnormally high. A relief valve or accumulator is installed in the cylinder body to prevent this, so even if the temperature of the hydraulic cylinder increases due to long-term use, the hydraulic cylinder itself or the driven mechanism or workpiece operated by this hydraulic cylinder will be protected. It has the advantage of being able to prevent deformation and destruction such as, etc., and can be used in practice over a wide temperature range.

Furthermore, even if it has the above effects,
Since the above-mentioned check valve, relief valve, or accumulator is installed inside the hydraulic cylinder, when used, there is no need to separately assemble a relief valve etc. or perform piping for that purpose after assembling the hydraulic cylinder. It is possible to reduce the labor required for installation, and at the same time, the number of parts can be extremely reduced, which has the effect of reducing the overall cost.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the present invention, FIG. 2 is an enlarged view of the main part of FIG. 1, and FIGS. 3 and 4 are partial views showing different embodiments. A...Cylinder main body, 5...Piston, 16...Valve chamber (valve sliding chamber), 1T...
・Check valve, 17a... Valve body (non-sliding body), 1
8, 19...Valve hole, 30.31...Relief valve, 36...Accumulator.

Claims (1)

[Scope of utility model registration request] In the above-mentioned swing type hydraulic cylinder, a piston is slidably fitted into a cylinder chamber of a cylinder body, and an oil supply and drainage path for supplying oil for sliding the piston is provided in the cylinder body. Valve sliding chambers are provided in the middle of the oil supply and drainage passages within the cylinder body, and each of these non-sliding chambers is slidable, allowing oil to be supplied to the oil supply and drainage passages on the corresponding side to one end side. These non-sliding bodies are fitted so as to be slidable and slid toward the other end when oil is supplied to the other oil supply/drainage passage, and these non-sliding bodies are fitted with a groove that slides toward the one end. In this state, the valve hole opens due to the supply of oil to the oil supply/discharge path, but when the supply of oil is stopped, the valve hole closes, and when the valve is slid toward the other end, the valve hole opens. Each cylinder is equipped with a check valve, and the cylinder body or piston is provided with a check valve that is actuated by the supplied oil and causes the pressure to become abnormally high when the pressure of the supplied oil supplied to the cylinder chamber exceeds the set pressure. Hydraulic cylinder provided with a relief pulp or accumulator designed to prevent