JP2553728Y2 - Swash plate tilting device for swash plate type piston pump / motor - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a swash plate tilting device for a swash plate type piston pump / motor.

[0002]

2. Description of the Related Art A cylinder block is rotatably arranged together with a shaft in a case, a piston is inserted into a cylinder hole of the cylinder block to form a cylinder chamber, and the piston is slidable along a swash plate. A swash plate type piston pump motor in which a cylinder chamber is opened to a high pressure port and a low pressure port on a valve plate at every 180-degree rotation is known. A device for tilting a swash plate in such a swash plate type piston pump / motor is disclosed in, for example, JP-A-59-79078. That is, a swash plate is supported in the case so as to be tiltable, and a tilting piston is provided in the case so as to face the front surface of the swash plate. A device that tilts the swash plate by expanding and contracting the tilting piston by switching the switching valve.

[0003]

[Problem to be solved by the invention] With such an apparatus,
Drilling the pilot passage in the case increases processing cost, and it is difficult to remove dust and the like in the pilot passage, and dust and the like may be mixed in oil flowing through the pilot passage and damage hydraulic equipment. Or, the case becomes large.

Accordingly, an object of the present invention is to provide a swash plate tilting device for a swash plate type piston pump / motor which can solve the above-mentioned problems.

[0005]

A variable piston 23 for swinging the swash plate 10 is provided at the top dead center position and the bottom dead center position of the case 3, respectively, and an extension chamber 27 of the variable piston 23 is formed in the variable piston 23. Shaft holes 25 and 26, an oil hole 28 formed at the top dead center position and the bottom dead center position of the swash plate 10, and a cylinder chamber of the piston 7 reaching the top dead center / bottom dead center through the shaft hole 33 of the piston shoe 9. 8 and the valve plate 1
A switching valve 41 for forming a port 40 at each of a top dead center position and a bottom dead center position between the high pressure port 12 and the low pressure port 13 and controlling the communication of each port 40 between a high pressure side and a low pressure side.
Swash plate tilting device for swash plate type piston pump / motor equipped with

[0006]

[Operation] By switching the switching valve 41, the extension chamber 27 of the variable piston 23 at the top dead center or the variable piston 23 at the bottom dead center is changed.
By supplying high-pressure oil to the extension chamber 27, the swash plate 10 can be swung to change the swash plate angle, and the variable piston 23, the swash plate 10, and the piston shoe 9 are formed with shaft holes and oil holes. It is sufficient to form the port 40 in the valve plate 11, which not only facilitates processing, but also has a short shaft hole and an oil hole, which can easily discharge dust powder and the like. And the case 3 can be made compact.

[0007]

[Embodiment] As shown in FIG. 1, a cylindrical body 1 and an end plate 2 are bolted together to form a case 3, in which a cylinder block 4 is rotatably arranged together with a shaft 5, and the cylinder block 4 is provided. Piston 7 in cylinder hole 6 of 4
To form a cylinder chamber 8, a piston shoe 9 connected to the piston 7 is slidable along a swash plate 10, and a valve plate 11 provided between the cylinder block 4 and the end plate 2. High pressure port 12 and low pressure port 1 that are substantially semicircular
2, the cylinder chamber 8 moving from the bottom dead center toward the top dead center is opened to the high pressure port 12, and at the top dead center, the cylinder chamber 8 is closed by the valve plate 11, as shown in FIG.
Cylinder chamber 8 that moves past bottom dead center toward bottom dead center
Opens into the low pressure port 13. The swash plate 10 is slidable along the arc-shaped concave portion 14 of the cylindrical body 1, and is vertically moved in FIG. Contact surfaces 15 and 16 are formed, and when the first contact surface 15 contacts the bottom 1a of the cylinder 1, the swash plate angle becomes small,
When the second contact surface 16 contacts the bottom 1a of the cylinder 1, the swash plate angle increases.

A cylinder hole 20 is formed at the vertical position in FIG. 1, that is, at the top dead center position and the bottom dead center position with respect to the center of the shaft 5 at the bottom 1 a of the cylindrical body 1. A piston 21 is inserted, and a sub-piston 22 is swingably provided on each main piston 21 to form a variable piston 23. The sub-piston 22 is
The first and second contact surfaces 15 and 16 are in contact with each other to form a space 24 therebetween. The space 24 communicates with the extension chamber 27 through the axial holes 25 and 26 of the auxiliary piston 22 and the main piston 21. The swash plate 10 is opened at the front surface 10a of the swash plate 10 with oil holes 28 formed at the top dead center position and the bottom dead center position.
8, a check valve 29 is provided. The extension chamber 27 communicates with a reduction chamber 31 through a small hole 30 of the main piston 21. The reduction chamber 31 opens into the case 3 and the main piston 21
Of the cylinder hole 20 at the end of the extension stroke
Is closed by the opening edge flange 20a.

The front surface 1 of the piston shoe 9 and the swash plate 10
0a, a circular space portion 32 is formed, and this space portion 32 is formed by a shaft hole 33 of the piston shoe 9 in the cylinder chamber 8.
The piston 32 and the space 32 of the piston shoe 9 located at the top dead center and the space 32 of the piston shoe 9 located at the bottom dead center respectively open in the oil hole 28 and are located at the top dead center. The extension chamber 27 of the variable piston 23 communicates with the cylinder chamber 8 located at the top dead center, and the extension chamber 27 of the variable piston 23 located at the bottom dead center communicates with the cylinder chamber 8 located at the bottom dead center. As shown in FIGS. 1 and 2, ports 40 are formed at the top dead center position and the bottom dead center position of the valve plate 11, respectively. Supplied.

The switching valve 41 is connected to the end plate 2 as shown in FIG.
A first port 45 that opens into a first oil hole 44 communicating with a port 40 at the top dead center, and a port 40 at the bottom dead center is inserted into the spool hole 42. A second port 47 that opens to a second oil hole 46 communicating with the oil pump and a third port 48 are formed. The third port 48 is an oil hole 49 and a shuttle valve or a check valve.
The spool 43 is pushed to the first position by the spring 50 and is pushed to the second position by the pressure oil in the pressure receiving chamber 51 against the spring 50 by communicating with the high pressure port 12 and the high pressure side of the low pressure port 13. , When the spool 43 is at the first position,
The oil hole 46 communicates with the case 3 via the second port 46 and the first small hole 52 at the port 53 at the port 53, the first port 45 communicates with the third port 48 at the first small diameter portion 54, and the spool 43
When it comes to the position, the first oil hole 44 communicates with the case 3 via the first port 45 and the second small hole 55 at the port 53, and the second port 47 communicates with the third port 48 at the second small diameter portion 56.
The pressure receiving chamber 51 is connected to a hydraulic source 58 and a tank 59 by a switching valve 57.
Is controlled.

Next, the operation will be described. When the switching valve 57 is set at the drain position A, the pressure receiving chamber 51 communicates with the tank 59, the spool 43 becomes the first position, the third port 48 communicates with the first port 45, and the high pressure oil is supplied to the port 40 on the top dead center side. Is supplied, and the port 40 at the bottom dead center side communicates with the inside of the case 3, so that high-pressure oil is supplied into the cylinder hole 8 that has reached the top dead center, and into the extension chamber 27 of the variable piston 23 at the top dead center. The high pressure oil is supplied, and the extension chamber 27 of the variable piston 23 at the bottom dead center side has a low pressure in the case 3. Thereby, the swash plate 10
Is pushed by the variable piston 23 on the top dead center side, and as shown in FIG. 1, the second abutment surface 16 abuts on the bottom 1a of the cylindrical body 1 to increase the swash plate angle. At this time, since the restrictor 30 of the main piston 21 is closed at the end of the extension stroke, the variable piston 23 is held by the check valve 29 so that the pressure oil in the extension chamber 27 does not flow out, and the extension chamber 27 is moved to the top dead center. The swash plate 10 does not return even if it does not communicate with the cylinder chamber 8 located. If the frictional moment of the swinging portion of the swash plate 10 is increased, the check valve 29 is not necessarily required because the swash plate 10 does not swing even if the pressure oil in the extension chamber 27 flows out.

As shown in FIG. 3, the switching valve 57 is moved to the supply position B.
Then, the pressure oil is supplied to the pressure receiving chamber 51, the spool 43 becomes the second position, and the first oil hole 44 becomes the first port 45 and the second oil hole 44.
The small hole 55 communicates with the inside of the case 3 via the port 53, and the inside of the extension chamber 27 of the variable piston 23 at the top dead center side has the same pressure as the low-pressure oil in the case 3, and the second oil hole 46 becomes the second port 47. The second small-diameter portion 56 communicates with the third port 48, high-pressure oil is supplied to the port 40 on the bottom dead center side, and high-pressure oil is supplied into the cylinder hole 8 that has reached the bottom dead center. High-pressure oil is supplied to the extension chamber 27 of the variable piston 23. As a result, as shown in FIG. 3, the variable piston 23 extends to swing the swash plate 10, and the first contact surface 15 is moved to the bottom 1a of the cylindrical body 1.
To reduce the swash plate angle. At this time, the variable piston 23 at the top dead center side is pushed to the contraction side by a slight swing of the swash plate 10, the expansion chamber 27 is opened into the case 3 by the throttle 30, and the high-pressure oil in the expansion chamber 27 is throttled. Since it is discharged into the case 3 at 30, the swing of the swash plate 10 is not hindered.

[0013]

By switching the switching valve 41, the extension chamber 27 of the variable piston 23 at the top dead center or the variable piston 2 at the bottom dead center is switched.
By supplying high-pressure oil to the third expansion chamber 27, the swash plate 10 can be swung to change the swash plate angle. Shaft holes and oil holes are formed in the variable piston 23, the swash plate 10, and the piston shoe 9, and the valve plate 1
It is sufficient that the port 40 is formed in 1 and not only the processing becomes easy, but also the shaft hole and oil hole are short, and the dust and the like can be easily discharged. And the case 3 can be made compact.

[Brief description of the drawings]

FIG. 1 is an overall sectional view.

FIG. 2 is a front view of a valve plate.

FIG. 3 is an operation explanatory diagram.

[Explanation of symbols]

3 case, 4 cylinder block, 5 shaft, 6 cylinder hole, 7 piston, 8 cylinder chamber, 9 piston shoe, 10 swash plate, 11 valve plate, 12 high pressure port, 13 low pressure port, 23 variable piston, 25 shaft hole, 26 Shaft hole, 27 extension chamber, 28 oil hole, 33 shaft hole, 40 ports, 41 switching valve.

Claims (1)

(57) [Scope of request for utility model registration] A cylinder block is rotatably supported in a case together with a shaft, and a piston is inserted into a cylinder hole of the cylinder block to form a cylinder chamber. A piston shoe 9 which is in open communication with a high pressure port 12 and a low pressure port 13 of a valve plate 11 so that the piston 7 can slide along a swash plate 10.
A variable piston 23 for swinging the swash plate 10 is provided at the top dead center position and the bottom dead center position of the case 3, and the extension chamber 27 of the variable piston 23 is connected to the variable piston. Shaft holes 25 and 26 formed at 23, an oil hole 28 formed at the top dead center position of the swash plate 10, a bottom dead center position, and the piston 7 reaching the top dead center / bottom dead center at the shaft hole 33 of the piston shoe 9. Each of the ports 4 communicates with the cylinder chambers 8 at the upper dead center position and the lower dead center position between the high pressure port 12 and the low pressure port 13 of the valve plate 11.
A swash plate tilting device for a swash plate type piston pump / motor, characterized in that a switching valve 41 is formed to form each of the ports 0 and communicate with each of the ports 40 between the high pressure side and the low pressure side.