JPH0331959B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field]

The present invention is a technology that can be suitably used for a rotary fluid pressure cylinder, etc. as a drive source for operating a chuck for a lathe, and is a technology that can be suitably used for a rotary fluid pressure cylinder or the like as a drive source for operating a chuck for a lathe. Concerning the structure of a rotating joint.

[Conventional technology]

The structure of the conventional rotary joint for fluids is
As is clear from No. 24803, it had a structure in which an annular flow path was interposed in the middle of the fluid passage when supplying pressurized fluid from a stationary body to a rotating body.
The drawback was that a large amount of pressurized fluid leaked from the wide gap created between the stationary part and the rotating part. In order to further reduce the leakage of the pressurized fluid, the gap should be made very small, or the distance between the annular flow path for the pressurized fluid going to the consuming device and the annular flow path for the consuming fluid returning through the consuming device should be reduced. The only way to do this is to make the joint wider and to separate them further apart, which has disadvantages such as an increase in heat generation, seizure, and an increase in the overall length of the fluid rotary joint. Further improved, JP-A-56-131882 discloses no technical disclosure regarding the fact that the arrangement positions of the pressurized fluid path and the consumption fluid path play an extremely important role in preventing leakage of the pressurized fluid. In addition, in order to further reduce the leakage of the pressurized fluid, it is important to soften the impact generated by the pressurized fluid. However, nothing has been disclosed regarding such technology.

[Problem to be solved by the invention]

SUMMARY OF THE INVENTION The present invention aims to solve the disadvantages of such conventional devices, namely, the occurrence of shock due to the pressurized fluid and the large amount of leakage of the pressurized fluid.

[Means to solve the problem]

The present invention successfully solves the above-mentioned drawbacks, and has the following features: a stationary body equipped with a fluid passage; a rotating body that is rotatably supported by the stationary body;
and a sleeve interposed between the two,
The sleeve is provided with a plurality of fluid passages oriented in the radial direction, and the rotating body is provided with a bow-shaped communication chamber that communicates with at least one of the fluid passages. A flow velocity buffer is provided at the inner end of the fluid path, and the cross section of the flow velocity buffer has a shape that gradually widens toward the communication chamber.

[Effect]

The pressure drop gradient between the low pressure on the front side in the rotational direction and the high pressure on the rear side in the rotational direction due to the fluid in the communication chamber that occurs as the rotating body rotates is gradually reduced in the circumferential length direction of the flow velocity buffer part. Therefore, the pressure drop gradient becomes smaller. Furthermore, the flow velocity damping section, which has a diverging shape that gradually increases as it approaches the communication chamber, significantly reduces the impact of the pressurized fluid and also prevents the occurrence of turbulent flow.

【Example】

A specific embodiment of a rotary hydraulic cylinder in which the fluid is oil and is used to open and close a chuck will be described. FIG. 1 is a partially cutaway perspective view of a rotary hydraulic cylinder consisting of a liquid supply body A and a rotary body B provided with a fluid consumption device, and FIG. 2 is a longitudinal sectional view of the cylinder. In the figure, 1 is a cylinder, 2 is a piston rod, and 3 is a piston fixed on the piston rod 2, which is slidably fitted into the cavity 4 of the cylinder 1. Reference numeral 5 denotes a rotary valve into which the piston rod 2 is fitted, and a locking mechanism 6, 6' for regulating the flow direction of oil in only one direction is incorporated therein. It is joined together. 8, 9, and 10 are O-rings for keeping the cavity 4 airtight. Reference numeral 11 denotes a guide pin fixed to the piston 3, and either end P or P' of the guide pin is always guided into a guide pin hole 12 provided in the cylinder 1 or the rotary valve 5 (in the illustrated example, toward the cylinder side). As a result, free rotation of the piston rod 2 is restricted. On the other hand, one end of the piston rod 2 is threadedly connected to a draw tube (not shown) to move the chuck. On the other hand, the rotary valve 5 is provided with two large and small key-shaped steps, one of which is a large-diameter key-shaped step K1, and the other is a small-diameter key-shaped step K2. A sleeve body 13 is provided in part K2. The sleeve 14 is press-fitted into the sleeve body 13 in the following manner. That is, the bearings 15, 15' fitted into both ends of the sleeve 14
One of the bearings (15 in the illustrated example) is in direct contact with the inner wall of the sleeve body 13, and the other bearing (15' in the illustrated example) is attached to the inner side of the sleeve cover 17, which is joined to the sleeve body 13 with bolts 16. It is fixed and integrated so that it comes into contact with the wall. Therefore, the inner periphery of the sleeve 14, which is stationary together with the sleeve body 13, is always in contact with the outer periphery of the rotating small-diameter key-shaped step part K2 through a slight gap, and the radial gap of this minute gap is usually This is a tiny gap of several tens of microns. Further, a stopper 18 is attached to the end edge of the small diameter key-shaped stepped portion K2.
It is attached using 9. Next, the operation of the piston 3 within the cylinder 1 will be explained as follows. Pressurized oil from an external supply device (oil tank) (not shown) is supplied to the oil passage 2 through the inlet 24 of the sleeve body 13.
5, the lock mechanism 6, the oil passage 26, and the oil chamber 2.
7 to press and move the piston 3. Oil chamber 27' pushed out as the piston 3 moves
The consumed oil passes through the lock mechanism 6', the oil passage 25', and is recovered from the outlet 24' to the external supply device. When the forward stroke of the piston due to the above action is completed and the piston moves to the backward stroke, the switching valve (not shown) is switched so that the aforementioned discharge port 24' becomes the inlet and the inlet 24 becomes the discharge port. The reverse process is performed by making the circuit. At this time, the small amount of pressurized oil is caused by the small gap T between the rotary valve 5 and the sleeve 14.
It is supplied to the bearings 15, 15' on both sides through T' and, after lubricating the bearings 15, 15', is collected through the drain sump 22 to an external supply device. At this time, a communication hole f is formed inside the sleeve 14, and the annular oil drain passages f1 and f2 are made to communicate with each other, so that the amount of oil supplied to both bearings 15, 15' is kept in balance. . Through the operations described in detail above, the chuck is opened and closed during operation or stop, a workpiece (not shown) is grasped by the chuck, and machining of the workpiece is performed while maintaining this state. Next, improvements to the rotary joint structure will be explained using FIGS. 3 to 6. Figure 3 is Z-Z of Figure 2.
A cross-sectional view, FIG. 4 is a perspective view of the sleeve 14, and FIG.
The figure is a perspective view of the rotary valve 5, and FIG. 6 is a sleeve 1.
Pressurized fluid path 25b and consumption fluid path 25'b in 4
FIG. 3 is a partially enlarged view of a developed plan view showing an arrangement state of the . As is clear from FIG. 4, on the outer periphery of the sleeve 14, annular oil passages 25a and 25'a are provided in parallel at a distance, and a large number of annular oil passages 25a and 25'a are provided at appropriate radial positions in communication with the oil passages. Fluid channels (six each in FIG. 3) are bored radially. The fluid path is
A pressurized fluid passage 25b for passing pressurized fluid and a consumption fluid passage 25'b for passing consuming fluid are formed.
On the other hand, the outer periphery of the rotary valve 5 shown in FIG. There are multiple communication rooms that have been cut out. The communication passage is formed of a supply communication chamber 25c that communicates with the pressurized fluid passage 25b and a discharge communication chamber 25'c that communicates with the consumption fluid passage 25'b (in the third illustrated example, there are two communication chambers in each communication chamber). (The book's fluid path is shown open). However, the pressurized oil supplied from the inlet 24 is
A large number of pressurized fluid passages 25 pass through an annular oil passage 25a.
b, 25b, . On the other hand, the consumed oil pushed out to the oil passage 25' is transferred to the discharge communication chamber 2.
5'c and then a large number of consumption fluid paths 25'b,
25'b,... to the annular oil passage 25'a.
It is returned to the oil tank and collected through the outlet 24'. When the pressing force of the pressurized oil is applied to the rotary valve 5 in a balanced manner in the radial direction as shown in FIG. 3, it is advantageous in that the rotary valve 5 does not rotate under an eccentric load state. Therefore, it is preferable that the pressurized fluid passages 25b, 25b, . . . and the consumption fluid passages 25'b, 25'b, . , and a supply communication chamber 25c and a discharge communication chamber 2 that open corresponding to this oil passage.
It is also important to provide the valves 5'c at multiple locations on the rotary valve 5 at equal intervals and to form a structure that does not receive eccentric loads. In the embodiments described above, the sleeve body 13 and the sleeve 14 are constructed as separate bodies, but they can be constructed as an integrated supply body, and a large number of oil passages are directly provided in the supply body in an equally divided arrangement. It is a good thing. Further, a bow-shaped flow velocity buffer portion S formed in a shape that widens at the end is capable of reducing the flow velocity of the fluid as it approaches the communication chamber without suddenly communicating or abruptly blocking the fluid in the rotary valve 5;
S' is provided at the inner end of the fluid path. Further, due to its viscosity, oil, which is a fluid, intervening in the minute gap between the inner wall surface of the sleeve 14, which is a stationary body, and the outer circumferential surface of the small-diameter key-shaped stepped portion K2 of the rotary valve 5, moves toward the front side in the direction of rotation in the communication chamber. There is a pressure drop gradient where the pressure is low in the rear part and high pressure in the rear part, but due to the special shape of the flow velocity buffer parts S and S', the pressure drop gradient becomes gentle and the flow velocity of the oil slows down. The shock will be alleviated. Another idea is that the rows of pressurized fluid paths 25b, 25b, ... and the consumption fluid path 25' are
In the rows 25'b, 25'b, . To explain the operation in detail, the pressurized oil to be supplied is exchanged through a small gap formed in the non-contact part between the pressurized fluid path 25b and the supply communication chamber 25c, and the surrounding area is exchanged through this small gap. An outflow (leakage) occurs. This leakage occurs in the annular oil drain path f
1 and f2 to the drain reservoir 22, and when they are arranged in a staggered manner, the distance L between them can be increased, so leakage of the pressurized oil becomes extremely small. Incidentally, it is also possible to provide a plurality of sets of the staggered fluid passages in the sleeve 14 and use them.

【Effect of the invention】

According to the present invention, it is possible to reduce the impact when the pressurized fluid flows, and furthermore, it is possible to gradually reduce the pressure difference, which is effective in reducing the flow velocity, and furthermore, it is possible to prevent turbulent flow, thereby reducing noise. It exhibits excellent effects that make it possible. These are excellent in that they allow the rotation to start up quickly and shorten idle time.
Furthermore, there is little leakage of pressurized fluid, and shear heat associated with leakage can be extremely reduced. In addition, since the distance l between the annular circumferential grooves can be reduced, this is very advantageous in terms of making the device smaller and more compact. In particular, assuming that the leakage amount between this example and the conventional one is the same, it is possible to select a large microgap, making it possible to roughen the pressurizing accuracy, which is effective in reducing the number of machining steps. Moreover, it also exhibits an extremely excellent effect in reducing torque resistance. In addition, when communicating chambers are formed on the outer periphery of the rotating body at equal intervals, this is very effective in preventing vibrations of the rotating part during high-speed rotation.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway perspective view of a rotary hydraulic cylinder, FIG. 2 is a longitudinal sectional view of the entire cylinder, FIG. 3 is a Z-Z sectional view of FIG. 2, and FIG. 4 is a sleeve 1.
4, FIG. 5 is a perspective view of the rotary valve 5, and FIG. 6 is a partially enlarged exploded plan view showing the arrangement of the pressurized fluid path and the digestive fluid path within the sleeve 14. 1...Cylinder, 2...Piston rod, 3...
... Piston, 5 ... Rotary valve, 6, 6' ... Lock mechanism, 13 ... Sleeve body, 14 ... Sleeve, 24 ... Inlet, 24' ... Discharge port, 2
5, 25'...oil passage, 25a, 25'a...annular oil passage, 25b...pressurized fluid passage (fluid passage), 25'b...
...Consumption fluid path (fluid path), 25c...Supply communication chamber (communication chamber), 25'c...Discharge communication chamber (communication chamber), 2
7, 27'...Oil chamber, A...Supply body (stationary body), B
...Rotating body, S, S'...Flow velocity buffer.

Claims (1)

[Scope of Claims] 1. It is formed of a stationary body equipped with a fluid passage, a rotating body that is rotatably supported by the stationary body, and a sleeve interposed between the two, and the sleeve contains a large number of fluids. The rotary body is provided with an arch-shaped communication chamber communicating with at least one of the fluid passages, and an inner end of the fluid passage is provided with a passageway oriented in a radial direction. A rotary joint for a fluid, characterized in that a flow velocity buffering portion is provided therein, and the cross section of the flow velocity buffering portion is formed in a shape that gradually widens towards the end as it approaches the communication chamber. 2. The fluid rotary joint according to claim 1, wherein the fluid passages in the sleeve are provided in parallel in the axial direction and in a staggered arrangement.