JPH048574B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application This invention relates to a swing joint for hydraulic construction machinery, etc., and more particularly to a novel swing joint equipped with a directional control valve function.

(B) Prior art Conventionally, this type of swivel joint has a structure as shown in Fig. 2 (Japanese Utility Model Publication No. 46-33300). is simply provided with a plurality of sets of oil passages 21A, 21B that communicate with a plurality of actuators (not shown); for example, one set of oil passages 21A is connected to the pipe line 24A of one directional control valve 17 and the swivel joint case. It only had the function of communicating with the oil passage 22A of No. 1.

(c) Problems to be Solved by the Invention Also, there are restrictions on the arrangement of the operating direction of the spools of the switching valves 17 and 18 and the port positions (it is natural to provide the port positions in a direction perpendicular to the operating direction of the spools). Since a plurality of pipes 24A and 24B are required between the switching valves 17 and 18 and the joint body 23, the number of pipes and the number of pipe connections on the upper revolving structure are large, which is industrially disadvantageous. However, the disadvantage is that problems such as oil leakage are likely to occur.

The present invention was made in order to eliminate the drawbacks of the conventional swing joints for construction machinery, etc., as described above, and an object of the present invention is to provide a novel swing joint having a directional control valve function in the joint body. do.

(d) Means for Solving the Problems The present invention solves the above problems by providing a spool hole in a swivel joint and fitting a spool having a switching valve function into the spool hole. That is, the swivel joint according to the present invention includes a swivel joint case 1 that is fixed to the lower traveling body A and has a plurality of sets of first oil passages 1A and 1B that communicate with a plurality of actuators.
In a swivel joint for a hydraulic construction machine, etc., which includes a joint body 3 rotatably fitted in this swivel joint case 1, and an upper rotating body B fixed to this joint body 3, this joint body A plurality of spool holes 4, 5 and a second oil passage 6 communicating with the return pipe 28 of the tank 25 are provided in the spool hole 4,
Annular oil spools 7 and 8 are fitted in the inner circumference of the swivel joint case 1 and independently communicate with the first oil passages 1A1 and 1A2; 1B1 and 1B2, respectively. Road 2A1, 2A
2; 2B1, 2B2 are provided, and each spool 7, 8 is provided with discharge pipes 26, 2 of the pumps 9, 10.
Main oil passages 13, 14 communicating with 7, and main oil passages 13,
14 and open to the cylindrical surfaces of the spools 7, 8, and annular ports 7A provided on both sides of the switching ports 11, 12.
1, 7A2; 8A1, 8A2, and the second
The oil passage 6 has a first branch opening 6A that can communicate with the first switching port 11 and any one of the first set of annular ports 7A1 and 7A2, and the second switching port 12 and the second set of annular ports. A second branch opening 6B that can communicate with either one of 8A1 and 8A2 is formed, and a first set of second oil passages 2A is formed in the joint body 3.
1 and 2A2, respectively, and a first switching port 11 and a pair of annular ports 7A1 and 7A.
The third oil passage 3A of the first set that can communicate with either of
1, 3A2, and the second set of second oil passages 2B1, 2B2.
and the second switching port 1.
2 and the second set of third oil passages 3 that can communicate with either of the second set of annular ports 7B1 and 7B2.
B1, 3B2 are provided.

(e) Operation When the spool is in the neutral state, the switching ports communicate with the tank through the branch opening, the second oil line, and the return pipe. That is, the oil discharged from each pump is returned to the tank via the discharge pipe, the main oil passage, the switching port, the branch opening, the second oil passage, and the return pipe. In this state, the actuator is not operated by oil discharged from the pump.
When the spool is operated upward or downward from the neutral state to communicate the switching port with one annular oil passage of one set via the third oil passage, the discharge oil of the pump is transferred to the discharge pipe, the main oil passage, One of the actuators of one of the plurality of actuators (not shown) passes through the switching port, one third oil passage of one set, one annular oil passage of one set, and one first oil passage of one set. port and actuates this actuator in one direction. The operating shaft that has completed its work is the other port of this actuator, the other first oil passage of one set, the other annular oil passage of one set, the other third oil passage of one set, and the other of one set. It returns to the tank via one annular port, a branch opening, a second oil line and a return line. If the spool is operated from the neutral position in the opposite direction, the actuator will be operated in the opposite direction. In this way, pressure oil is supplied from the pump attached to the upper rotating body to actuators such as travel motors attached to the lower rotating body, while return oil from the actuator is supplied to the actuators attached to the upper rotating body. It can be returned to the tank where it is.

(F) Embodiments The present invention will be described in detail below based on drawings showing embodiments thereof. In FIG. 1, 1 is a swivel joint case fixed to the undercarriage A;
A and 1B are two sets of first oil passages provided in the swivel joint case 1 and communicating with two actuators (not shown). The first oil passage 1A of the first set is oil passage 1A.
1 and an oil passage 1A2. Similarly, the second set of first oil passages 1B consists of an oil passage 1B1 and an oil passage 1B2. Reference numeral 3 denotes a joint body fixed to the upper revolving body B and rotatably fitted in the swivel joint case 1, and 4 and 5 are spool holes provided in the joint body 3, respectively. Spools 7 and 8, which will be described later, can be fitted into the spool holes 4 and 5.
The joint body 3 has a switching port 11 of the spool 7 or a first set of annular ports 7A1 and 7, which will be described later.
A first set of third oil passages 3A1 and 3A2 are provided to enable communication between A2 and the first set of annular oil passages 2A1 and 2A2 provided in the swivel joint case 1,
Similarly, the switching port 12 of the spool 8 or the second set of annular ports 8A1, 8A2 and the second set of annular oil passages 2B1 provided in the swivel joint case 1,
2B2 of the second set to enable communication with 2B2.
Oil passages 3B1 and 3B2 are provided. Furthermore, inside the joint body 3, there is a second oil passage 6 that communicates with the return pipe 28 of the tank 25, and a first branch opening that selectively communicates with either the first switching port 11 or the first set of annular ports 7A1. 6A, and a second branch opening 6B that selects and communicates with either the second switching port 12 or the second set of annular ports 8A2. 7 and 8 are spool holes 4 and 5 respectively
This spool is a spool that switches an oil passage that is movably fitted inside the first spool 7, and a first main oil that introduces the discharge oil of the first pump 9 through the first discharge pipe 26 into the first spool 7. passage 13, an annular first switching opening on the circumference of the first spool 7 and communicating with the first main oil passage 13, and opening on the circumference of the first spool 7 and communicating with the first main oil passage 13. Port 11 and first switching port 1
1, one of the first oil passages 1A of the first set.
1 is in communication with the first switching port 11, the other first oil passage 1A2 of the first set can be communicated with the second oil passage 6, and the other first oil passage 1A2 of the first set is in communication with the first oil passage 6. It has a first set of annular ports 7A1 and 7A2 that can communicate one first oil passage 1A1 of the first set with the second oil passage 6 when communicating with the switching port 11, and similarly, Inside the second spool 8, there is a second main oil passage 14 through which the discharge oil of the second pump 10 is introduced via a second discharge pipe line 27, and a second main oil passage 14 that opens on the circumference of the second spool 8. An annular second tube communicating with the passage 14
When the first oil passage 1B1, which is provided on both sides of the switching port 12 and the second switching port 12 and which is one of the second set, communicates with the second main oil passage 14, the other first oil passage 1B2 of the second set is connected to the second main oil passage 14. can communicate with the second oil passage 6, and the other first oil passage 1B2 of the second set is connected to the second main oil passage 14.
When communicating with one of the first oil passages 1B of the second set
1 and a second set of annular ports 7B1 and 7B2 that can communicate with the second oil passage 6.

Note that the check valves 15A and 15B have branch openings 6, respectively, in order to prevent the hydraulic oil from the switching ports 11 and 12 from flowing back to each other.
A, 6B, and springs 16A, 16
B is for maintaining the spools 7, 8 in a neutral state when they are not operated, and is provided at the lower end of the spools 7, 8. Although not shown, each spool 7, 8 is also provided on the upper side. Furthermore, although the drain route from the actuator (not shown) is not shown, any known means may be used to drain the switching valve. That is, the space in which the springs 16A and 16B are accommodated is communicated with the tank 25 via a pipe line, and this space is connected to the drain pipe line of the actuator via channels provided in the joint body 3 and the swivel joint case 1, respectively. communicate.

In this embodiment, two actuators are used, but three actuators may be used as necessary.
Of course, it is possible to use more than one.

Next, the operation of this embodiment will be explained. Figure 1 shows
The first spool 7 is shown switched upward from the neutral state, and the second spool 8 is shown switched downward from the neutral state. 1st spool 7
is restricted from being operated higher than this by a stopper (not shown). Similarly, the second
The spool 8 is restricted by a stopper (not shown) so that it cannot be operated lower than this. The hydraulic oil discharged from the first pump 9 reaches the first switching port 11 via the first discharge pipe 26, the first main oil passage 13 of the first spool 7, and the first switching port 11 of the joint body 3.
It flows into one actuator (not shown) through the third oil passage 3A2 above the set, the annular oil passage 2A2 above the first set of the swivel joint case 1, and the first oil passage 1A2 above the first set. Drive one actuator in one direction. Next, the hydraulic oil that has finished its work is transferred to the first oil passage 1A1 below the first set, the annular oil passage 2A1 below the first set, the third oil passage 3A1 below the first set, and the third oil passage 3A1 below the first set. annular port 7A1, first
It returns to the tank 25 via the branch opening 6A, the second oil path 6, and the return pipe 28.

When the first spool 7 is switched from the neutral position to the downward direction opposite to that shown in the figure, the lower first oil passage 1A1 of the first set becomes the pressure side, and the upper first oil passage 1A2 of the first set becomes the return side. One actuator (not shown) is driven in the opposite direction.

Similarly, the hydraulic oil discharged from the second pump 10 flows into the other actuator (not shown) using the lower first oil passage 1B1 of the second set as the pressure side, and drives the other actuator in either direction. The hydraulic oil that has finished its work is transferred to the first oil passage 1 on the upper side of the second set.
Pass through B2 and return to tank 25. When the second spool 8 is switched from the neutral position upwards opposite to that shown, the other actuator is driven in the opposite direction.

(g) Effects of the Invention As described above, according to the swivel joint for construction machinery, etc. of the present invention, it is possible to provide a novel swivel joint in which the joint body has the function of a directional control valve, and it is possible to Only one return pipe to the tank is required for each of the switching valves, and the number of pipes that connect multiple switching valves and the joint body, which is twice the number of switching valves, is no longer required. This has become industrially advantageous, and has also made it possible to reduce problems such as oil leaks.

[Brief explanation of drawings]

FIG. 1 is a longitudinal cross-sectional view of the swivel joint of the present invention,
FIG. 2 is a longitudinal sectional view of a conventional swivel joint. 1... Swivel joint case, 1A: 1B... First oil path,
2A1; 2A2; 2B1; 2B2...Annular oil passage, 3
...Joint body, 3A1; 3A2; 3A3; 3B1;
3B2; 3B3... Third oil path, 4; 5... Spool hole, 6... Second oil path, 6A; 6B... Branch opening, 7;
8...Spool, 7A1; 7A2; 8A1; 8A2
...Annular port, 9;10...Pump, 11;12...
Switching port, 13; 14... Main oil line, 25... Tank, 26; 27... Discharge pipe line, 28... Return pipe line, A
...lower traveling body, B...upper rotating body.

Claims (1)

[Claims] 1 A swivel joint case 1 that is fixed to the lower traveling body A and has a plurality of sets of first oil passages 1A and 1B that communicate with a plurality of actuators, and a joint body 3 that is rotatably fitted into the swivel joint case 1. In a swing joint for a hydraulic construction machine, etc., which includes an upper rotating body B fixed to the joint body 3, a plurality of spool holes 4, 5 and a tank 25 are provided in the joint body 3.
a second oil passage 6 communicating with the return pipe 28 of the
Spools 7 and 8 that are fitted into the spool holes 4 and 5 and movable in the axial direction are provided, and first oil passages 1A1 and 1A are provided in the inner circumference of the swivel joint case 1.
Annular oil passages 2A1, 2A2, 2B1, 2B2 are provided which independently communicate with the spools 7, 8, and pumps 9, 1 are connected to each spool 7, 8, respectively.
A main oil passage 13 communicating with the discharge pipes 26 and 27 of 0,
14, and a spool 7 communicating with the main oil passages 13 and 14,
an annular switching port 11 that opens on the cylindrical surface of 8;
12, and annular ports 7A1, 7A2 provided on both sides of the switching ports 11, 12; 8A1, 8A2
The second oil passage 6 has a first branch opening 6A that can communicate with the first switching port 11 and any one of the first set of annular ports 7A1 and 7A2.
and a second branch opening 6B that can communicate with the second switching port 12 and one of the second set of annular ports 8A1 and 8A2, and the joint body 3 has a second oil passage of the first set. 2A1, 2A2, respectively, and a first set of third oil passages 3A1, 3A2 that can communicate with either the first switching port 11 and one set of annular ports 7A1, 7A2, and a second set of second oil passages. 2B1, 2B2, respectively, and a second set of third oil passages 3B1, 3B2 that can communicate with either the second switching port 12 and the second set of annular ports 7B1, 7B2 are formed. Swivel joints for construction machinery, etc.