JP2559113Y2 - Hydraulic transmission device hydraulic oil supply device - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charge pump circuit for replenishing hydraulic oil in a closed circuit when hydraulic oil is reduced.

[0002]

2. Description of the Related Art Conventionally, in a center section provided with a pair of oil passages for connecting a hydraulic pump and a hydraulic motor, a horizontal hole formed in each of the pair of oil passages of the oil passage is provided, and an inlet of each check valve is provided. The pump discharge oil was guided from the joined pump case into the center section, the supply oil pressure was set by the pressure setting means in the center section, and the port was drilled in the center of the lateral hole. It was connected to another oilway.

[0003]

However, the conventional technique has a disadvantage that the number of oil passages drilled in the center section increases, the machining cost increases, and the cost increases. It is. The present invention solves the above-mentioned disadvantages of the prior art. When casting and manufacturing a center section and a pump case, the oil passage can be formed at the same time. Is cheap.

[0004]

The problems to be solved by the present invention are as described above. Next, means for solving the problems will be described. A pair connecting the hydraulic pump P and the hydraulic motor M
Lower surface of center section 2 provided with oil passages 20 and 21
To the pump case 3 containing the charge pump 9
And the mating surface of the center section 2 and the pump case 3
The charge pump 9 is fitted on the pump case 3 side of the
From the large pump 9 to the oil passages 20 and 21 respectively.
A configuration for replenishing the arranged check valves 6a and 6b with hydraulic oil
, The pressure for setting the supply oil pressure of the charge pump 9
The force setting means 22 is provided in the pump case 3 so that the center section
The check valve 6 is provided on the joint surface between the
Oil spanning the inlet ports 24a and 24b of a and 6b
The oil passage 23 is connected to the inlet port 24a.
24b, the oil passage 23 and the pressure setting
The charge pump is connected to the adjustment port 25 of the stage 22.
9 from the pressure setting means 2 in the pump case 3.
2 to adjust the pressure to a set pressure.
Adjustment port 25, pump case 3 and center section
2 to be supplied to the oil passage 23 opened at the mating surface .

[0005]

Next, the operation will be described. The pressure oil generated by the charge pump 9 is adjusted to an appropriate oil pressure by the pressure setting means 22 in the pump case 3, and is supplied from the oil passage 23 to the inlet ports 24 a and 24 b of the check valves 6 a and 6 b, and the hydraulic oil is supplied. When it decreases, the check valves 6a and 6b are opened, and hydraulic oil is supplied to the oil passages 20 and 21 from the inlet ports 24a and 24b.

Next, an embodiment will be described. FIG. 1 is a plan view of the hydraulic transmission according to the present invention with the half upper case 1a removed, FIG. 2 is a cross-sectional view taken along the line AA of FIG. 1, and FIG. B of FIG.
4 is a sectional view taken along the line CC of FIG. 5, FIG. 4 is a sectional view taken along the line DD of FIG. 3, and FIG. 6 is a sectional view taken along the line D-D of FIG. 7 is a hydraulic circuit diagram of the hydraulic oil supply device of the hydraulic transmission according to the present invention, and FIG. 8 is an embodiment of another hydraulic circuit of the hydraulic oil supply device of the hydraulic transmission according to the present invention. FIG.

1 and 2, the overall configuration of an axle drive having a hydraulic transmission will be described. The transmission case 1 is configured to join upper and lower half cases at a horizontal joining surface. The upper half case 1a and the lower half case 1b are joined in a horizontal plane.
On the horizontal joint surface, bearings of the axles 13L and 13R are sandwiched, and the motor shaft 14 and the counter shaft 5 are also supported by bearings. Also, at the joint surface between the half upper case 1a and the half lower case 1b, the center section 2 is attached and fixed to the lower surface of the half upper case 1a with three bolts 50 from below. A hydraulic pump P is supported on a horizontal plane of the center section 2, and a hydraulic motor M is supported on a vertical plane of the center section 2.

A pump shaft 10 of the hydraulic pump P projects from the upper half case 1a, and the input pulley 3
0 is fixed. The engine E is connected to the input pulley 30.
Is transmitted by the V-belt. The pump shaft 1
The rotation of 0 causes the rotation of the cylinder block 7, and the plurality of pump pistons 47 loosely fitted inside the cylinder block 7 rotate while moving forward and backward along the movable swash plate 45, thereby supplying and discharging the pressure oil. Perform the action.

A pair of kidney ports 20a and 21a are opened in the pump mounting surface of the center section 2, and a pair of linear oil passages 20 are formed in the center section 2.
・ Communicating with 21. A pair of kidney ports 20b and 21b are also opened on the motor mounting surface of the center section 2, and an oil passage is provided at the end of the oil passage 20 so as to be orthogonally connected to the kidney port 20b. It is directly connected to the kidney port 21b. With this oil passage configuration, hydraulic oil circulates between the hydraulic pump P and the hydraulic motor M.

A motor piston 46 is inserted into a plurality of cylinder holes of the cylinder block 8 provided on the vertical surface of the center section 2, and pressure oil supplied from the hydraulic pump P is supplied to the cylinder hole of the cylinder block 8. When supplied to the inside, the motor piston 46 advances and retreats, and generates a rotational force along the fixed swash plate 34, thereby rotating the cylinder block 8, and the motor shaft 14 with which the cylinder block 8 is engaged is rotated. A small-diameter gear 36 is engraved on the motor shaft 14, and a large-diameter gear 3 of the counter shaft 15 is attached to the small-diameter gear 36.
7 are engaged. The small-diameter gear 40 on the counter shaft 15 meshes with the ring gear 41 of the differential gear device 42. The differential gear device 42 is rotated by the ring gear 41, and transmits the rotation to the left and right axles 13L and 13R. The fixed swash plate 34 is fitted and fixed to a swash plate support 48, and a brake ball 39 is fitted on a side of the swash plate support 48 opposite to the fixed swash plate 34. The brake ball 39 is moved in and out by the brake cam plate 35 being rotated via the brake lever 32 and the brake lever shaft 12, and presses and releases the brake disc 38 to perform a brake operation.

The rotation of the transmission lever 31 of FIG. 2 causes the transmission lever shaft 43 of FIG. 1 to rotate, and the transmission lever 44 fixed to a portion of the transmission case 1 protruding into the transmission case 1. Rotates. The rotation of the shift lever 44 becomes the rotation of the movable swash plate 45, thereby performing forward and backward and neutral shifts. In addition, the rotation of the forced neutral lever 33 causes the branch arm 16 at the distal end of the forced neutral lever shaft 11 to enter and exit, and the distal end of the branched arm 16 forcibly opens the check valves 6a and 6b of the oil passages 20 and 21. By pressing the rods 19a and 19b to communicate both the oil passages 20 and 21, the high pressure circuit and the low pressure circuit of the hydraulic transmission are connected to obtain a neutral position.

The check valves 6a and 6b are supported by check valve cases 17a and 17b. Similarly, the forcibly opening rods 19a and 19b are also connected to the check valve cases 17a and 17b.
7b. As shown in FIG. 2, the pump case 3 is joined to the lower surface of the center section 2 at a position opposite to the pump support surface, and is fixed by fixing bolts 18. A pump fitting recess of the charge pump 9 is formed on the joint surface of the center section 2 and the pump case 3 on the pump case 3 side. The charge pump 9 is engaged with a pump shaft 10, and with the rotation of the pump shaft 10,
The pump gear rotates and discharges the hydraulic oil supply pressure oil.

A part of the pressure oil discharged from the charge pump 9 is used for replenishing hydraulic oil in a closed circuit of the hydraulic transmission, while another part is supplied from a PTO hydraulic port 51.
The hydraulic pressure is controlled by another hydraulic control valve 52 for working equipment, and is supplied to a hydraulic cylinder 53 for other working equipment. Fig. 3.
4 and 5, the configuration of the center section 2, the pump case 3, and the oil filter 4 will be described. As shown in FIG. 3, oil passages 20 and 21 are bored inside the horizontal portion of the center section 2, and the open ends of the oil passages 20 and 21 have check valve cases 17 and 21, respectively.
Check valves 6a and 6b supported by a and 17b are fitted. Check valve cases 17a and 17b
The forcibly opening rods 19a and 19b are slidably supported by the fork, and the forcible opening rods 19a and 19b are pressed by the branch arm 16 to tow a vehicle having the axle driving device. , The hydraulic transmission is returned to the neutral position.

4 and 5, the arrangement of the pressure setting means 22, which is a main part of the present invention, will be described. A charge pump 9 is arranged on a joint surface between the center section 2 and the pump case 3, and discharge pressure oil from the charge pump 9 is supplied to pressure setting means 22 in the pump case 3. The supplied pressure oil is adjusted to a set pressure by a pressure setting means 22 and supplied from an oil passage 25 to an oil passage 23 opened at a mating surface of the center section 2. The oil passage 23 is formed in a long groove extending over the inlet ports 24a and 24b of the check valves 6a and 6b.
Is supplied to the inlet ports 24a and 24b. The self-priming check valve 5 is arranged at the center position of the oil passage 23, so that the supply oil cannot be forcibly supplied from the charge pump 9 due to a failure of the charge pump 9 or the supply oil is insufficient. A self-priming check valve 5 is provided for sucking hydraulic oil by itself in the event of this. Normally, the self-priming check valve 5 closes the oil passage 26 by the pressure oil from the charge pump 9, but when the pressure of the charge pump 9 decreases, the self-priming check valve 5 opens. The hydraulic oil filtered by the oil filter 4 is sucked.

In the hydraulic transmission of the embodiment, the discharge oil from the charge pump 9 is adjusted to a predetermined set pressure to a pair of oil passages connecting the hydraulic pump P and the hydraulic motor M, and the check valve 6a. 6b to open the inlet ports 24a and 24b
Although the hydraulic transmission is more replenished, the hydraulic transmission may be damaged if hydraulic pressure is not supplied for some reason due to a failure of the charge pump 9 or the like. Therefore, the self-priming check valve 5 is arranged in the oil passage 23, and an oil passage 26 for communicating the inlet port of the self-priming check valve 5 with the inside of the transmission case 1 is formed in the pump case 3. The oil filter 4 is interposed in the portion. The oil filter 4 and the self-priming check valve 5 cause the hydraulic oil to leak from the rotary sliding parts of the hydraulic pump P and the hydraulic motor M, and when the high pressure side of the pair of oil passages 20 and 21 becomes negative, When the suction check valve 5 is opened, the hydraulic oil in the transmission case 1 can be guided into the oil passage 23 and supplied to the low pressure side via the check valves 6a and 6b.

In the embodiment shown in FIG. 6, the inlet ports 24a of the check valves 6a and 6b provided in the center section 2 are provided.
Each of the pump cases 3 is opened at the joint surface to the pump case 3 and both inlet ports 24
A long groove extending over the openings a and 24b is formed, and the oil passage 23 is formed by joining with the center section 2.

As described above, the oil passage 23 constituting the hydraulic oil supply circuit is formed by joining the center section 2 and the pump case 3, and the long groove is formed on the center section 2 side as shown in FIG. It may be formed on the pump case 3 side as shown in FIG. 6, or may be formed on both sides.

FIGS. 7 and 8 show a hydraulic circuit of the hydraulic transmission according to the present invention. The pressure setting means 22 used in the present invention is constituted by a pressure reducing valve type as shown in FIG. Or a relief valve type as shown in FIG.

In both hydraulic circuits, the charge pump 9
A part of the discharge oil of the working machine is taken out from the PTO hydraulic port through another working machine hydraulic control valve 52 and the working machine hydraulic cylinder 53
Is configured to be driven. The driving oil pressure is adjusted by an external oil pressure setting relief valve 55.

[0020]

[Effects of the Invention] The present invention is constructed as described above, and has the following effects. First, when the center section 2 and the pump case 3 are manufactured by casting, the oil passages 23 constituting the hydraulic oil supply circuit can be formed at the same time. Costs can be reduced. Second, by arranging the pressure setting means 22 inside the pump case 3, a simple hydraulic transmission could be achieved. Third, inside the pump case 3
Pressure adjustment is provided by the adjustment port 25 provided and the long oil passage 23.
Setting means 22 and the inlet ports 24a of the check valves 6a and 6b.
・ It is possible to adjust the pressure oil up to 24b
When the discharge pressure of the charge pump 9 fluctuates without being constant,
In this case, the adjustment port 25 and the long oil passage 23
Can be adjusted to almost constant pressure, so check
Chattering may occur when opening and closing the valves 6a and 6b.
And it became less.

[Brief description of the drawings]

FIG. 1 is an upper half case 1a of the hydraulic transmission according to the present invention;
FIG.

FIG. 2 is a sectional view taken along the line AA of FIG. 1;

FIG. 3 is a sectional view taken along the line BB of FIG. 5 showing a section of the oil passages 20 and 21 in the center section 2.

FIG. 4 is a sectional view taken along the line CC of FIG. 5;

FIG. 5 is a sectional view taken along the line DD of FIG. 3;

FIG. 6 is a sectional view taken along the line DD of FIG. 3 showing another embodiment.

FIG. 7 is a hydraulic circuit diagram of the hydraulic oil supply device of the hydraulic transmission according to the present invention.

FIG. 8 is a view showing another embodiment of the hydraulic circuit of the hydraulic oil supply device of the hydraulic transmission according to the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Transmission case 2 Center section 3 Pump case 4 Oil filter 5 Self-priming check valve 9 Charge pump 22 Pressure setting means 23 Oil passage

Claims (1)

(57) [Scope of request for utility model registration] 1. A hydraulic pump P and a hydraulic motor M are connected.
Below the center section 2 provided with a pair of oil passages 20 and 21
The pump case 3 containing the charge pump 9
Align the center section 2 with the pump case 3
The charge pump 9 is fitted on the pump case 3 side of the
From the charge pump 9, each of the oil passages 20 and 21
To supply hydraulic oil to the check valves 6a and 6b
In the operation, the supply hydraulic pressure of the charge pump 9 is set.
The pressure setting means 22 is provided on the pump case 3 and the center section is provided.
Check the check valve on the joint surface between the
6a and 6b, the length of which spans the inlet ports 24a and 24b.
An oil passage 23 is formed, and the oil passage 23 is connected to the inlet port 24a.
24b to communicate with both the oil passage 23 and the pressure setting
Communication with the adjustment port 25 of the means 22;
The oil discharged from the pump 9 is supplied to the pressure setting means in the pump case 3.
22 to adjust the pressure to a set pressure.
From adjustment port 25, pump case 3 and center section
To supply to the oil passage 23 opened at the mating surface of the
A hydraulic oil replenishing device for a hydraulic transmission.