JPS5911764B2 - fluid pressure cylinder - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a pneumatic, hydraulic, or other fluid pressure cylinder used to drive a mechanical chuck or other tightening device that is mainly attached to a spindle of a machine tool, and in particular, the present invention relates to a hydraulic cylinder such as a pneumatic or hydraulic cylinder used for driving a mechanical chuck or other tightening device mounted on a spindle of a machine tool. As shown in Japanese Patent Publication No. Sho 56-34405, which was previously filed by J.D., the gripping force of the jaws is changed by changing the thrust of the connecting rond, which is very effective when used for operating a chuck.

As a conventional fluid pressure cylinder of this type, the cylinder body is designed to prevent the internal fluid supplied into the cylinder chamber from flowing out and causing a pressure drop even if a failure occurs in the pressure source or fluid leaks in the middle of the supply piping. A type of fluid pressure cylinder with a built-in check valve has been proposed, but in such a fluid pressure cylinder, when the temperature of the entire fluid pressure cylinder rises, due to the difference in thermal expansion coefficient between the cylinder body and the sealed fluid. The internal pressure becomes abnormally high, sometimes deforming or destroying the cylinder itself, causing a major accident.Furthermore, in the case of a fluid pressure cylinder that incorporates a check valve as mentioned above, the external pressure may become abnormally high. Because the thrust of the piston rond cannot be reduced even if the source pressure is lowered, for example, the
This is extremely inconvenient for those that want to change the gripping force of the jaws by changing the thrust of the piston rond, such as the chuck described in Specification No. 6-34405, and there is a problem that it is virtually impossible to use this type of chuck. .

SUMMARY OF THE INVENTION The present invention aims to solve the above-mentioned problems, and a check valve is provided within the main body of the fluid pressure cylinder to prevent the operating pressure from decreasing due to the outflow of internal fluid. However, an increase in internal pressure due to temperature rise can be prevented with a simple configuration, and moreover, within a predetermined range of supply fluid pressure, the thrust of the piston rond can be reduced by lowering the pressure of the external pressure source. The present invention aims to provide a fluid pressure cylinder that can perform the following functions.

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

Fig. 1 shows an example of a rotating hydraulic cylinder for a chuck, in which the cylinder body 1 consists of a cylinder tube 2,
It is composed of a cylinder head cover 3 and a rod cover 4, and the rod cover 4 is attached to a spindle (not shown) and rotated.

A distributor 5 is fitted onto the shaft portion 3a of the cylinder head cover 3 so as to allow rotation of the shaft portion 3a.

A sliding hole 7 is formed in the piston 6 of the hydraulic cylinder,
In addition, the right cylinder chamber 9 is located in the rond part 8 of the piston 6.
An intermediate chamber 11 that is communicated with a through a communication hole 10 is formed in a.

A conductive shaft 12, which has a central portion of the cylinder head cover 3 protruding toward the rod cover 4, is slidably inserted into the sliding hole 7, and its tip is located in the intermediate chamber 11.

Reference numeral 13 denotes a supply and discharge passage for supplying and discharging oil to and from the left cylinder chamber 9b, and is provided within the cylinder head cover 3 and the cylinder tube 2.

Further, reference numeral 14 denotes a supply/discharge passage for supplying and discharging oil to the right cylinder chamber 9a, and is provided in the rad cover 3 over the tip of the conductive shaft 12 to the cylinder.

These supply/discharge passages 13, 14 communicate with the supply ports 1-15, 16 of the IJ computer 5, respectively, and from these supply ports 15, 16, the cylinder chamber 9a.

It is arranged so that oil can be supplied to and discharged from the oil pump 9b.

Note that the supply and discharge of oil to the right cylinder chamber 9a may be performed, for example, by a supply and discharge passage passing through the cylinder tube 2 and the rod cover 4;
, the communication hole 10, the intermediate chamber 11, and the conduction shaft 12 are unnecessary.

Inside the cylinder head cover 3 is a supply/discharge passage 13.1.
A control valve 17 is disposed in the middle of 4.

This control valve 17 is constructed as shown in FIG.
Next, this control valve 17 will be explained.

18 is a valve chamber formed in the middle of the above-mentioned supply/discharge passage 13.
Supply and discharge passages 13a and 14a on the 6 side are opened, respectively, and supply and discharge passages 13b and 14b on the cylinder chambers 9a and 9b side are opened on the inner surface of the upper and lower central portions, respectively.

In the valve chamber 18, closing bodies 19 and 20 are fitted and fixed at both upper and lower ends, and O-rings 21 and 22 are fitted on the outer circumferences of these bodies to prevent oil leakage.

These closing bodies 19.20 have supply and discharge passages 13a extending from both ends of the valve chamber 18 to the supply port 1-15.16 side.

Communication grooves 23 and 24 are formed to communicate with the groove 14a.

Further, a control valve main body 25 is fitted in the valve chamber 18 between the closing bodies 19 and 20 so as to be slidable by a predetermined amount.

26, 27, and 28 are 0 1 fitted into the control valve body 25.
This is J-ng.

The control valve main body 25 has a non-sliding chamber 29 that opens at the end surface.
30 and the inner part of these non-sliding chambers 29 and 30 is the cylinder chamber 9a.

Communication hole 3 communicating with the supply/discharge passages 13b and 14b on the 9b side
1.32 are formed respectively.

A valve main body 36.36 of a check valve 33.34 is fitted in the non-sliding chamber 29.30 so as to be slidable in the longitudinal direction of the control valve main body, and a snap fitting is fitted into the control valve main body 25. The control valve body 25 is biased towards the center in the longitudinal direction by the IJ spring 41° 42 which is compressed and interposed between the retainer 39° 40 which is prevented from coming out by the rings 37 and 38, and the non-sliding chamber is closed. It is in contact with the inner surface of 29.30.

A valve hole 43.44 and a non-accommodating hole 45.46 are formed in these valve bodies 35, 36 through valve seats 47, 48, and the non-accommodating hole 45, 46 is connected to the control valve body 25. Communication holes 49 and 50 are formed to communicate with the holes 31 and 32.

Valve bodies 51 and 52 are accommodated in the non-accommodating holes 45 and 46, and a snap ring 53 fitted to the valve body 35 and 36
．． At 54, the valve seat 47 is biased by check springs 57 and 58 which are compressed and interposed between the retaining brackets 55 and 56.
48.

59.60 is an O-ring fitted into the valve body 51.52.

Next, 61.62 is inserted into the closing body 19.20 forming a part of the inner surface of the non-sliding chamber 29.30 so as to protrude by an appropriate amount toward the valve holes 43, 44 of the valve body 35.36. With the formed legs, when the control valve body 25 or the valve body 35.36 is slid towards the closure body 19.20, the valve bodies 51, 52
It comes into contact with the valve seats 47 and 48 and pushes them up from the valve seats 47 and 48.

Next, the operation of the above structure will be explained, but in order to make this explanation easier, the valve bodies 35. of the check valves 33.34.
The area sealed by 36 O-rings 59.60 is A
, 'J IJ-Cylinder chamber 9a of pressure oil supplied with F1 thrust of springs 41 and 42.

The pressure at part 9b (hereinafter referred to as internal pressure) is P (in),
Similarly, the pressure at the supply port N5.16 (hereinafter referred to as external force) is P(out), F:A=P(SI))
.

P(in)−P(out)” ΔP.

Now, when pressure oil is supplied from the supply port 16, the pressure oil first moves the control valve body 25 upward to the blocker 19 in FIGS.
Slide it until it touches the.

Due to this sliding of the control valve body 25, the valve body 51 of the check valve 33 on the return side (upper side in FIG. 2) comes into contact with the leg piece 61 and is pushed up against the check spring 57, and the valve seat 47 The valve hole 43 is opened by moving away from the valve.

Therefore, the oil in the left cylinder chamber 9b is transferred to the supply and discharge passage 13.
through which it is possible to return to the supply port 15.

Next, the pressure oil pushes the valve body 52 of the check valve 34 against the check spring 58.
, and flows into the non-storage hole 46 and the communication hole 50, and then flows through the communication hole 32 of the control valve body 25 and the supply/discharge passage 14b.
1, enters the right cylinder chamber 9a through the intermediate chamber 11 and the communication hole 10, and slides the piston 6 to the left in FIG.

In this case, since the check valve 33 is opened as described above, the oil in the left cylinder chamber 9b is returned into the tank (not shown) through the supply port 15.

The chuck grips the workpiece due to the sliding of the piston 6, and when the sliding of the piston 6 is stopped, the valve body 52 of the check valve 34 is moved by the elasticity of the check spring 58 to the valve seat 48 to prevent leakage. It is crimped and processed in this state.

As mentioned above, since the valve body 52 of the check valve 34 is pressed against the valve seat 48, the external pressure P Even if (out) decreases to some extent, △P becomes P(s
If the internal pressure P (in) is smaller than IJ I
Since there is no possibility of overcoming the J-fu spring 42 and causing the valve body 36 to slide, the internal pressure P (in) is maintained at the initial pressure and the piston 6 continues to be reliably located at its original position.

Therefore, even if the external pressure P(out) decreases to some extent due to oil leakage or the like, the gripping force of the chuck will not decrease accordingly.

Next, when the external pressure P (out) decreases significantly due to, for example, a power outage and ΔP becomes larger than P (sp), the internal pressure P (in) resists the relief spring 42 and the valve body 36 , the internal volume increases and the internal pressure P (in) begins to decrease.

In this case, the compression of the relief spring 42 causes P(
sp) increases, and the sliding of the valve body 36 causes the valve body 52 to move closer to the leg piece 6.
When △P becomes smaller than P(sp) before coming into contact with the valve body 36, the sliding of the valve body 36 stops and P(out)+P(sp
)=P(in) holds true.

Further, in the above case, even when the valve body 52 comes into contact with the leg piece 62, if ΔP is still larger than P(sp), the valve body
2 comes into contact with the leg piece 62, which causes the valve body 52 to crank once and the internal pressure P (in) decreases, and △P becomes P (sp
), the valve body 52 is pressed against the valve seat 48 again, and P(out)+P(sp)=P(in).

Therefore, by reducing the external pressure P(out), the internal pressure P(in) can be reduced.

This has the advantage that, for example, the gripping force of the chuck can be freely controlled within a predetermined range from large to small and from small to large while gripping the workpiece.

In the above case, even if the external pressure P(out) becomes zero, the internal pressure P becomes P(in) - P(sp) due to the relationship P(out) + P(sp) - P(in).
(in) never becomes zero, and the gripping force of the chuck is P
It is maintained above a certain size set by (sp).

Further, in general, when the valve body 52 and the valve seat 48 are sealed by metal contact, it is difficult to avoid minute leakage between them, and a certain amount of leakage occurs, resulting in a decrease in internal pressure. In this case, even if leakage occurs as described above, the leakage is allowed only outside the volume in which the valve body 36 slides against the IJ IJ-F spring 42, and the internal pressure is maintained for a long time.

Next, with pressure oil sealed in the cylinder chamber a as described above, if the temperature of the entire hydraulic cylinder rises due to a rise in outside air temperature or a rise in oil temperature due to use, the temperature between the cylinder body 1 and the oil will rise. The internal pressure P (in) in the cylinder chamber a begins to rise due to the difference in the coefficient of thermal expansion, but when this internal pressure P (in) becomes greater than P (out) + P (sp), the valve body 36 becomes IJ IJ- When the valve body 52 slides against the spring 42 and comes into contact with the leg piece 62 as described above, it cracks once and the internal pressure P (in) decreases.
(out)+P(sp)=P(in).

Therefore, the internal pressure P(in) is P(out)+P(sp
), and even if the temperature of the entire hydraulic cylinder rises as mentioned above, the internal pressure in the cylinder chamber a will no longer become abnormally high, which will prevent damage to the cylinder body 1, etc. This prevents deformation and deformation.

Next, when the piston 6 is to be slid to the right in FIG.
Supply pressure oil to.

This pressure oil causes the control valve main body 25 to slide downward in FIG. This allows the oil in the right cylinder chamber a to return to the supply port 16.

Thereafter, the pressure oil pushes up the valve body 51 of the check valve 33 and enters the cylinder chamber 9b, causing the piston 6 to slide to the right while causing the oil in the cylinder chamber a to flow backward.

Then, when the piston 6 stops sliding, the valve body 51 of the check valve 33 is pressed against the valve seat 47.

Therefore, in this case as well, it is possible to prevent the pressure in the cylinder chamber 9b from decreasing due to a decrease in the pressure of the supplied oil.

In addition, when the temperature of the hydraulic cylinder rises, this pressure oil will cause the valve body 35 to
Since the valve body 51 comes into contact with the leg piece 61 and is pushed up, the pressure of the oil in the cylinder chamber 9b does not become abnormally high.

FIG. 3 shows a second embodiment of the present application.

In this embodiment, the control valve main body 25e is fixedly housed in the valve chamber 18e, and the non-sliding chambers 29e, 30e formed in the control valve main body 25e are provided with closing bodies 19e, 20e.
are fitted and prevented from coming off by snap rings 63 and 64.

Further, the valve bodies 35e and 36e slidably fitted into the non-sliding chambers 29e and 30e are relief springs 41e.

42e is in contact with the closing bodies 19e and 20e.

Furthermore, the control valve main body 25e has a non-sliding chamber 29e.
, 30e, and a control piston 66 is fitted in the sliding hole 65 so as to be slidable between the receivers 39e and 40e.

Both end surfaces of this control piston 66 are non-sliding chambers 29e.

30e, and leg pieces 61 are provided on both end surfaces.
e, 62e are provided protrudingly.

These leg pieces 61e, 62e are connected to the control piston 66 by the support 39.
When the valve body 51e is slid to a position where it contacts e or 40e, the valve body 51e
Alternatively, it protrudes by a sufficient amount to come into contact with and push up the valve body 52e.

67 is 01Jng.

In the structure as described above, the supply/discharge passage 14ae
When pressure oil is supplied to , this pressure oil causes the control piston 66 to slide upward in FIG. 3, thereby causing the leg piece 61e to
comes into contact with the valve body 51e of the check valve 33e, pushes up the valve body 51e, and opens the return side check valve 33e.

Moreover, when pressure oil is supplied to the other supply/discharge passage 13ae,
The pressure oil in turn causes the control piston 66 to slide downward in FIG. 3, thereby opening the check valve 34e.

It should be noted that parts that are considered to have the same or equivalent configuration as those of the above embodiment are given the same reference numerals as those of the corresponding parts of the above embodiment with the letter "e" added thereto, as necessary, and redundant explanation is omitted.

(Similarly for the next third example, the alphabet f
) Figure 4 shows a third embodiment of the present application, in which the supply and discharge passage 13
A single control valve 17Af, 17 is installed in the middle of each of f and 14f.
Bf is configured.

With this configuration, when pressure oil is supplied to the supply/discharge passage 14af, this pressure oil flows through the pilot passage 68 and slides the return side control valve body 25Af, thereby causing the check valve 33f to slide. will be released.

Moreover, when pressure oil is supplied to the other supply/discharge passage 13af,
This pressure oil flows through the pilot passage 69 and the control valve body 25
Bf is slid, thereby opening the check valve 34f.

In the above embodiment, a control valve is provided in each of the two supply/discharge passages, but for example, when attempting to control only the pressure oil in the cylinder chamber 9a shown in FIG. As shown in FIG. 5, a control valve 178f may be provided in the middle of the supply/discharge passage 14f communicating with the cylinder chamber 9a.
When pressure oil is supplied to the other supply/discharge passage 13f, this control valve 17Bf flows through the pilot passage 69 and slides the control valve main body 25Bf, thereby causing the check valve 34f to slide.
will be released.

In FIG. 5, the same parts as in the third embodiment are given the same numbers.

Further, the control valves may be arranged parallel to each other on the central axis.

As described above, in the present invention, since a check valve is provided within the cylinder body, the pressure of the supplied fluid may drop due to fluid leakage during piping to the fluid pressure cylinder or failure of the pressure source. Even when the piston is rotated for chuck operation, the pressure of the fluid sealed in the cylinder chamber does not drop to zero, and the piston can be held in its original working position with a thrust greater than a predetermined amount. When used in cylinders, it has the safety effect of preventing a significant drop in the gripping force of the workpiece and preventing the workpiece from coming off.

In addition, the valve body of the check valve is made slidable, and when the pressure of the fluid sealed in the cylinder chamber rises, the valve body is slid to open the check valve, so the temperature of the fluid pressure cylinder is reduced. Even when the pressure rises, the pressure of the fluid sealed in the cylinder chamber can be prevented from becoming abnormally high, and there is an effect that deformation or damage of the fluid pressure cylinder itself, driven mechanism, workpiece, etc. can be prevented.

Furthermore, even if a check valve is provided, since it is configured as described above, by lowering the external pressure, the internal pressure can be lowered within a predetermined range, and the cylinder thrust can be reduced. It has the effect of being able to be used without any problems when operating a power chuck where the gripping force needs to be changed in accordance with changes.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a fluid pressure cylinder showing the first embodiment of the present application, FIG. 2 is an enlarged explanatory view of the main part of FIG. 1, and FIG. 3 is an explanatory view of the main part showing a second actual case. FIG. 4 is an explanatory diagram of main parts showing a third embodiment, and FIG. 5 is a diagram showing a different embodiment. 1...Cylinder body, 9a, 9b...
・Cylinder chamber, 13.14... Supply and discharge passage, 1
5.16... Supply port, 18... Valve chamber, 25... Control valve body, 29, 30...
...Non-sliding chamber, 33.34...Check valve, 35.
36... Valve body, 41.42... Relief spring, 61.62... Leg piece.

Claims (1)

[Claims] 1. A valve chamber is formed in the middle of at least one of the supply and discharge passages in one cylinder body, a control valve body is fitted in this valve chamber, a valve sliding chamber is formed in this control valve body, and this non-sliding The valve body of the check valve is slidably fitted in the chamber, and an IJ spring is provided to bias the valve body toward the supply/discharge passage communicating with the cylinder chamber. The valve body is brought into contact with the inner surface of the non-sliding chamber of the valve body, a valve body is disposed within the valve body so as to be movable in the axial direction of the valve body, and the valve body is biased in a direction opposite to the direction in which the valve body is biased. When the valve body is pressed against the valve seat of the valve body, and the valve body of the check valve is slid against the tip of the valve body or the inside of the non-sliding chamber in the biasing direction of the valve body, the valve body is slid against the spring. A leg piece is provided that comes into contact with the inner surface of the non-sliding body or the tip of the valve body to release the contact state between the valve body and the valve seat, and furthermore, by supplying pressurized fluid to the other supply/discharge passage, the inside of the valve chamber is A fluid pressure cylinder configured to release a contact state between a valve body and a valve seat by sliding a control valve body or a leg piece.