JP3225239B2 - Rotary joint - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a rotary joint. For example, a hydraulic frame such as a hydraulic crane that can be pivotally mounted on a truck frame, a hydraulic work machine such as a shovel or backhoe that can be pivotally mounted on a self-propelled vehicle, or an attachment that has a rotating mechanism, etc. A hydraulic pump and a tank are placed on the vehicle side, and an operating valve and an actuator such as a cylinder are mounted on a working machine such as a crane, a shovel, or a backhoe, which is a turning member. Supply and discharge of hydraulic oil during these
In order to enable 360 ° turning on the work machine side, even if a hose is used, it may not be possible because it may be threaded, and a rotary joint that allows supply and discharge of hydraulic oil while allowing turning is inevitable. Must be used. The present invention relates to a rotary joint that supplies and discharges a pressurized fluid from a fixed pipe on a fixed frame side to a driven pipe on a turning frame side used in such an application. The pressure fluid according to the present invention includes water, air, and the like in addition to hydraulic oil.

[0002]

2. Description of the Related Art A conventional rotary joint is shown in FIGS.
It will be described based on. In the figure, reference numeral 51 denotes a mounting plate mounted on the fixed frame side, and an inner cylindrical member 52 is fixed at the center thereof. The inner cylindrical member 52 has a columnar shape, and a plurality of circumferentially extending oil grooves 53 (six in the illustrated example) are formed on the outer peripheral surface at intervals in the vertical direction. The same number of vertical holes 54 are formed in the vertical direction inside the inner cylindrical member 52, and one oil hole 53 is connected to one vertical hole 54 in a corresponding manner. A female screw is cut at the lower end of the vertical hole 54 so that a fixed pipe can be connected. On the other hand, the outer cylinder member 56
Are rotatably fitted, and the outer cylinder member 56 is fixed to a turning frame (not shown). The outer cylinder member is formed with the same number of the horizontal grooves 53 as the above-mentioned horizontal grooves 53 at intervals in the vertical direction in the radial direction. A female screw is formed at the outer end of the lateral hole 57 so that a driven pipe can be connected. In the rotary joint having the above-described structure, two of the six vertical holes 54 and the horizontal holes 57 correspond to one actuator, and the vertical hole 54 side of the inner cylinder member 52 is connected via an operation valve. The hydraulic cylinder is connected to a hydraulic pump and a tank, and the lateral hole 57 side of the outer cylinder member 56 is connected to an actuator such as a cylinder. And the operating position of the operating valve,
Eventually, one oil passage becomes high pressure and the other oil passage becomes low pressure depending on the operation direction of the actuator. When the operation direction of the actuator is changed, one oil passage changes to low pressure and the other oil passage changes to high pressure. As described above, the pressure in the plurality of sets of the oil groove 53 and the horizontal hole 57 of the rotary joint constantly changes between high and low, and this high-pressure oil is applied to the outer peripheral surface of the inner cylinder member 52 and the outer cylinder member 56. A packing 58 is provided below the lowermost oil groove 53, and a packing 59 is also provided above the uppermost oil groove 53 so as not to leak from a sliding surface between the oil groove 53 and the inner peripheral surface. Further, a drain groove 61 is formed circumferentially between the lowermost oil groove 53 and the lower packing 58, and a drain lateral hole 62 extending inward in the radial direction is formed. Also, the uppermost oil groove 53 and the upper packing 59
Between them, a drain groove 63 is formed circumferentially, and a drain lateral hole 64 extending inward in the radial direction is formed. A drain vertical hole 65 connecting the drain horizontal hole 64 and the drain horizontal hole 62 is formed up and down in the inner member 52, and a lower end thereof is female-threaded to be connected to a fixed drain pipe on the fixed frame side. It is supposed to be.

[0003]

However, in the above-mentioned prior art, even if high-pressure oil leaks to the sliding surface between the inner cylinder member 52 and the outer cylinder member 56, the high-pressure oil is drained before reaching the upper and lower packings 58, 59. Although hydraulic oil can be collected in the circuit, a drain pipe must always be provided on the fixed frame side. This makes the piping on the narrow fixed frame side difficult, and even if the piping is forced, the maintenance and inspection thereof become extremely difficult. In addition, when an attachment having a rotation mechanism is retrofitted to an existing work machine or the like, there is often no space for providing a drain pipe, and in that case, the attachment cannot be attached.

In view of the foregoing, the present invention provides a rotary joint that does not require a drain pipe, is easy to handle and maintain, and allows an attachment having a rotating mechanism to be mounted without space for the drain pipe. The purpose is to do.

[0005]

According to a first aspect of the present invention, there is provided a rotary joint comprising an inner cylindrical member on a fixed frame side and an outer cylindrical member on a revolving frame side, wherein the inner cylindrical member is for connecting a fixed pipe. Equipped with a plurality of vertical holes having a female screw at a lower end, the outer cylinder member communicates with each of the plurality of vertical holes of the inner cylinder member, and a female screw for connecting a driven pipe on the turning frame side. A plurality of port holes provided at an outer end portion are provided, and a plurality of oil grooves communicating the plurality of vertical holes and the plurality of port holes are provided on an outer peripheral surface of the inner cylindrical member or the outer cylindrical member. A rotary joint provided circumferentially at intervals on the inner peripheral surface of the inner cylindrical member, wherein the inner cylindrical member has a sliding surface above the uppermost oil groove and a lower part than the lowermost oil groove. Drain recovery path formed to communicate with the sliding surface of A check valve interposed between each of the oil grooves and the drain recovery path, wherein the check valve prevents inflow of pressure fluid from the oil groove to the drain recovery path, It is characterized in that it is interposed so as to allow the flow of the pressurized fluid from the drain recovery passage into the oil groove. The rotary joint according to claim 2 is the invention according to claim 1, wherein the drain recovery path includes a drain lateral hole extending radially inward from a sliding surface above an uppermost oil groove of the inner cylinder member, A drain lateral hole extending radially inward from a sliding surface below the lowermost oil groove of the cylindrical member, and a downward extending from an upper end of the inner cylindrical member to communicate with the two drain lateral holes; It consists of a drain vertical hole with a screw part,
The outer cylinder member includes a flange attached to an upper end thereof and having a female screw portion formed at a portion communicating with the drain vertical hole, and two plugs screwed to the two female screw portions. It is characterized by having. The rotary joint according to claim 3 is the invention according to claim 1, wherein the inner cylindrical member has a drain hole that penetrates from an upper end to a lower end, and has a female screw portion formed with a lower end portion to which a plug can be screwed. A flange attached to an upper end portion of the outer cylinder member and having a female screw portion capable of screwing a plug formed at a portion communicating with the drain hole, and being screwed to the two female screw portions; And a spare drain passage composed of two plugs.

According to the first aspect of the present invention, the 2
Of this set of oil passages, the high-pressure oil that has leaked from the high-pressure side oil passage to the sliding surface between the outer peripheral surface of the inner cylinder member and the inner peripheral surface of the outer cylinder member enters the drain recovery path, and The oil is collected in the oil groove on the low pressure side through the check valve in the oil passage. Even if the high-pressure side and the low-pressure side of the two oil paths are switched, the high-pressure oil is also recovered to the low-pressure side oil path through the check valve, so that the drain recovery is completed in the rotary joint. There is no need to discharge to the outside. For this reason, the drain circuit is not required, and the pipe and the attachment can be easily attached.
According to the second aspect of the present invention, if the drain pipe on the turning frame side is connected to the female screw portion of the flange, the drain outside the rotary joint can be collected by the drain collection path in the inner cylinder member. Moreover, since the drain does not discharge to the outside, there is no need to provide a drain pipe on the fixed frame side.
It can be installed even in a narrow space. According to the third aspect of the invention, if the two plugs are removed, the drain pipe on the revolving frame side is connected to the female screw portion of the flange, and the drain pipe on the fixed frame side is connected to the drain hole, the device on the revolving frame side Can flow to the fixed frame side, and can be diverted to a circuit configuration requiring a drain discharge circuit.

[0007]

Next, embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a longitudinal sectional view of a rotary joint according to a first embodiment of the present invention, FIG. 2 is a hydraulic circuit diagram of the rotary joint of the first embodiment, and FIG. 3 is a hydraulic diagram of an actuator driving device using the rotary joint of the present invention. 4 is a vertical sectional view of a rotary joint according to a second embodiment of the present invention, FIG. 5 is a bottom view of the rotary joint of FIG. 4, and FIG. 6 is a hydraulic circuit diagram of the rotary joint of the second embodiment. .

(First Embodiment) In FIG. 1, reference numeral 1 denotes an inner cylindrical member which is fixed to a fixed frame (not shown) (for example, a truck frame, a self-propelled vehicle frame, or a fixed side of an attachment). Reference numeral 2 denotes an outer cylinder member, which is a member attached to a revolving frame (not shown) (for example, a hydraulic working machine such as a rotatable hydraulic crane or a shovel / backhoe, or a revolving side of an attachment). The inner cylindrical member 1 is basically a columnar solid member, in which a plurality of (two in the illustrated example) vertical holes 3 and 4 are formed. The female screw is cut, and the fixed pipe on the fixed frame side is connected. On the other hand, the outer cylinder member 2 is a cylindrical hollow member, and is covered with the inner cylinder member 1 in a liquid-tight and swiveling manner. Port holes 7 and 8 are formed in a thick portion of the outer cylinder member 2, and two oil grooves 5 and 6 are circumferentially and vertically separated on an inner peripheral surface (sliding surface). It is formed. The port holes 7 and 8 communicate with the oil grooves 5 and 6. An external thread is cut at the outer end of each of the port holes 7, 8, so that a driven pipe on the turning frame side is connected. The fixed pipe and the driven pipe are formed of a rubber hose or the like outside the pipe.

A drain oil groove 11 is formed below the lower oil groove 5 on the inner peripheral surface (sliding surface) of the outer cylinder member 2, and a drain oil groove 12 is formed above the upper oil groove 6. Are formed. On the other hand, drain lateral holes 13 and 14 are formed in the inner cylindrical member 1 radially inward from a sliding surface facing the drain oil grooves 11 and 12.
3, 14 are communicated by one drain vertical hole 15. The upper end of the drain vertical hole 15 is closed by a blind plug 16. The drain horizontal holes 13 and 14 and the drain vertical hole 15 form a drain recovery path 17 (see FIG. 2).

A flange 2a is provided at the upper end of the outer cylindrical member 2.
An image chamber 32 communicating with the drain vertical hole 15 is formed on the lower surface of the flange 2a, and a female screw portion is provided at the center of the flange 2a so that the flanged plug 33 is screwed. It has become. A sealing material such as an O-ring or packing is provided on the upper and lower sliding surfaces of the oil grooves 5 and 6 and the drain oil grooves 11 and 12 of the outer cylinder member 2, and a dust seal 9 is attached to the lowermost end. ing.

In the inner cylindrical member 1, a drain vertical hole 15 is provided.
A communication passage is formed between the check valve 21 and the oil groove 5.
Is interposed. A communication passage is formed between the drain vertical hole 15 and the oil groove 6, and a check valve 22 is interposed. These check valves 21, 22 prevent the flow from the oil grooves 5, 6 to the vertical hole 15,
6 is interposed in a direction allowing flow.

FIG. 2 shows a hydraulic circuit (except for the compartment 32 and the plug 33) inside the rotary joint RJ. The drain recovery path 17 is completed inside the rotary joint RJ and is not discharged to the outside. It has become. FIG. 3 is a hydraulic circuit showing an example of a cylinder driving device using the rotary joint RJ. A directional control valve V, a pump P, and a tank T are arranged below the rotary joint RJ, and a cylinder CY, which is an actuator, is installed above the rotary joint RJ. The oil passages A and B are connected between the cylinder CY and the pump P.

Although the rotary joint RJ of the present invention is used in such a hydraulic circuit, the operation of drain recovery will be described by taking this as an example. In the illustrated state of FIG. 3, the direction control valve V is at the left position R, the cylinder CY is expanding, the oil passage A in the rotary joint RJ is at a high pressure, and the oil passage B is at a low pressure. In this case, high-pressure oil leaks from the oil passage A on the high-pressure side shown in FIGS. 1 and 2 to the sliding surface, and this high-pressure oil passes through the nearest drain horizontal hole 14 and the drain vertical hole 15.
The oil is collected in the low pressure side oil passage B via the check valve 21. In addition,
The check valve 22 prevents the high-pressure side oil groove 6 from flowing into the drain vertical hole 15, so that high-pressure oil does not flow. Next,
When the directional control valve V in FIG.
Side becomes high pressure and the oil path A side becomes low pressure. in this case,
The high-pressure oil leaks from the oil passage B to the sliding surface as shown in FIGS. Collected on Road A. The check valve 21 prevents the oil from flowing from the oil groove 5 on the high pressure side to the drain vertical hole 15, so that a large amount of high pressure oil is not discharged. Thus, according to the rotary joint of the present embodiment, the rotary joint RJ
Inside, the drain generated on the high pressure side can be collected in the low pressure side oil passage, so that there is no need to provide a drain pipe for discharging the drain to the outside.

In the above embodiment, if the drain pipe on the revolving frame side is removed from the plug 33 of the flange 2a and connected to its internal thread, and the blind plug 16 of the drain vertical hole 15 is removed, the inner cylindrical member 1 can be removed. Drain collection path inside
2. The drain outside the rotary joint can be collected by the drain vertical hole 15 and the check valves 21 and 22). Moreover,
Since the drain is not discharged to the outside, there is no need to provide a drain pipe on the fixed frame side, and the drain can be attached even in a narrow space.

(Second Embodiment) A second embodiment shown in FIGS. 4 to 6 is obtained by adding a spare drain passage to the configuration of the first embodiment. Therefore, since the basic configuration is the same as that of the first embodiment, the same components are denoted by the same reference numerals and description thereof is omitted. A drain hole 31 penetrates through the inner cylindrical member 2 from the upper end to the lower end, and the lower end is closed by a flanged plug 33. According to this embodiment,
If the flanged plug 33 of the flange 2a and the flanged plug 33 of the drain hole 31 are removed, the drain pipe on the turning frame side is connected to the female screw portion of the flange 2a, and the drain pipe on the fixed frame side is connected to the drain hole 31. In addition, the drain of the rotating frame side device can flow to the fixed frame side, and the rotary joint RJ can be directly applied to a circuit configuration requiring a drain discharge circuit. In addition,
The drain recovery effect inside the rotary joint RJ when the drain passage 31 is not used is the same as that of the first embodiment.

(Other Embodiments) In the above embodiment, the oil grooves 5 and 6 and the drain oil grooves 11 and 12 are formed on the inner peripheral surface of the outer cylinder member 2. Those formed are also included in the present invention. In each embodiment, the oil grooves 5, 6
As long as the vertical holes 3, 4 and the port holes 7, 8 communicate with each other, the drain horizontal holes 13, 14 only need to be able to collect high-pressure oil leaked to the sliding surface. In the above embodiment, the oil passages A and B are one set of two oil passages. However, the present invention can be applied to four or more oil passages and two or more sets.

[0017]

According to the first aspect of the present invention, of a pair of oil passages in the inner cylinder member, a portion between the outer peripheral surface of the inner cylinder member and the inner peripheral surface of the outer cylinder member from the high pressure side oil passage. High-pressure oil leaked to the sliding surface of
It enters the drain recovery path, passes through the check valve in the low-pressure side oil path, and is recovered in the low-pressure side oil groove. Even if the high-pressure side and the low-pressure side of the two oil paths are switched, the high-pressure oil is also recovered to the low-pressure side oil path through the check valve, so that the drain recovery is completed in the rotary joint. There is no need to discharge to the outside. For this reason, the drain circuit is not required, and the pipe and the attachment can be easily attached.
According to the second aspect of the present invention, if the drain pipe on the turning frame side is connected to the female screw portion of the flange, the drain outside the rotary joint can be collected by the drain collection path in the inner cylinder member. Moreover, since the drain does not discharge to the outside, there is no need to provide a drain pipe on the fixed frame side.
It can be installed even in a narrow space. According to the third aspect of the invention, if the two plugs are removed, the drain pipe on the revolving frame side is connected to the female screw portion of the flange, and the drain pipe on the fixed frame side is connected to the drain hole, the device on the revolving frame side Can flow to the fixed frame side, and can be diverted to a circuit configuration requiring a drain discharge circuit.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a rotary joint according to a first embodiment of the present invention.

FIG. 2 is a hydraulic circuit diagram of the rotary joint according to the present invention.

FIG. 3 is a hydraulic circuit diagram of an actuator driving device using the rotary joint of the present invention.

FIG. 4 is a longitudinal sectional view of a rotary joint according to a second embodiment of the present invention.

FIG. 5 is a bottom view of the rotary joint of FIG. 4;

FIG. 6 is a hydraulic circuit diagram of a rotary joint according to a second embodiment.

FIG. 7 is a longitudinal sectional view of a conventional rotary joint.

FIG. 8 is a bottom view of a conventional rotary joint.

[Explanation of symbols]

 Reference Signs List 1 inner cylinder member 2 outer cylinder member 3 vertical hole 4 vertical hole 5 oil groove 6 oil groove 7 horizontal hole 8 horizontal hole 13 drain horizontal hole 14 drain horizontal hole 15 drain vertical hole 21 check valve 22 check valve RJ rotary joint

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-59-61632 (JP, A) JP-A-53-36518 (JP, U) JP-A-58-172186 (JP, U) (58) Field (Int.Cl. ⁷ , DB name) B66C 13/12 E02F 9/00 F16L 39/04

Claims (3)

(57) [Claims] An inner cylinder member on a fixed frame side and an outer cylinder member on a revolving frame side, wherein the inner cylinder member has a plurality of vertical holes having a female screw at a lower end for connecting a fixed pipe. The outer cylinder member has a plurality of port holes which respectively communicate with the plurality of vertical holes of the inner cylinder member and have female threads at an outer end portion for connecting a driven pipe on the turning frame side. A plurality of oil grooves communicating with the plurality of vertical holes and the plurality of port holes are vertically arranged circumferentially on the outer peripheral surface of the inner cylindrical member or the inner peripheral surface of the outer cylindrical member. A rotary joint provided at intervals, wherein the inner cylinder member is formed so as to communicate between a sliding surface above the uppermost oil groove and a sliding surface below the lowermost oil groove. Between the drain grooves and the oil grooves and the drain recovery paths. A check valve, wherein the check valve prevents flow of pressure fluid from the oil groove to the drain recovery path, and allows flow of pressure fluid from the drain recovery path to the oil groove. A rotary joint characterized by being interposed. 2. A drain horizontal hole extending radially inward from a sliding surface above an uppermost oil groove of the inner cylinder member, a drain lateral hole extending below the lowermost oil groove of the inner cylinder member. A drain lateral hole extending radially inward from the sliding surface, and a drain vertical hole extending downward from the upper end of the inner cylindrical member, communicating with the two drain lateral holes, and having a female screw portion at an upper end portion, The outer cylinder member has a flange attached to an upper end thereof and having a female screw portion formed at a portion communicating with the drain vertical hole, and is screwed to the two female screw portions.
2. The rotary joint according to claim 1, wherein the rotary joint has a plurality of plugs. 3. A drain hole penetrating from an upper end to a lower end of the inner cylinder member and having a female screw portion formed at a lower end thereof into which a plug can be screwed, and a drain hole attached to an upper end of the outer cylinder member. A flange formed with a female screw portion into which a plug formed at a portion communicating with the drain hole can be screwed;
2. The rotary joint according to claim 1, further comprising a spare drain passage formed by two plugs screwed into the female screw portion at each location.