JPH0510415A - Hydraulic speed change gear - Google Patents

Abstract

PURPOSE:To improve the sliding state by providing each circular ring-shape change-over valve with numerous guide holes piercing both sliding contact faces of the change-over valve so as to communicate the cylinder port side sliding contact face with the sliding contact face on the ring hollow part bottom face side, thereby nullifying pressure difference between both faces. CONSTITUTION:A second change-over valve 23 coming in sliding contact with a second cylinder port 30 comes, at the other face thereof, in sliding contact with the bottom face of a ring hollow part 61. In the same way, a first change- over valve 22 coming in sliding contact with a first cylinder port 21 comes, at the other face thereof, in sliding contact with a ring hollow part 60. These change-over valves 22, 23 are respectively provided with numerous guide holes 66, 67 piercing both sliding contact faces. Both sliding contact faces are thereby communicated with each other to nullify pressure difference, so that force caused by the unbalance of pressure acting upon the change-over valves 22, 23 is nullified to improve the sliding state.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a hydraulic transmission, and more particularly to a hydraulic transmission suitable for transmitting rotational power of an input shaft to an output shaft via hydraulic pressure while changing the speed. The present invention relates to a pressure type transmission.

(Prior art and its problems) The power transmission efficiency is improved by dividing the power into mechanically transmitted power and power transmitted via liquid, and increasing the mechanically transmitted power at high load. There has been proposed a hydraulic transmission which is adapted to the above (see, for example, Japanese Patent Application No. 63-135651). The gist thereof is that a first rotating shaft, a second rotating shaft arranged concentrically with the first rotating shaft, and a first cylinder mechanically connected to the first rotating shaft. A barrel, a second cylinder barrel concentric with the second rotation shaft and rotatable relative thereto, an inner end face of the first cylinder barrel and an inner end face of the second cylinder barrel. And a valve block which is integrated with the above, and the first cylinder barrel, which is spaced apart from the outer end surface of the first cylinder barrel at a predetermined interval on a circle centered on its axis. A plurality of first cylinders extending substantially in the axial direction, and a first swash plate supported by a stationary casing and having an inclined surface capable of tilting about a tilt axis orthogonal to the first rotation axis. , Inserted in the first cylinder in a liquid-tight manner so that they can slide freely. A plurality of first pistons, which reciprocate when their outer ends are brought into sliding contact with the inclined surface of the first swash plate as the first cylinder barrel rotates, and the second piston on the second cylinder barrel. A plurality of second cylinders extending substantially in the axial direction from the end surface on a circle centered on the axial center thereof at predetermined intervals along the circumferential direction, and are integrated with the second rotary shaft. The second swash plate and the second swash plate are slidably inserted into the second cylinder in a liquid-tight manner, and the outer ends of the second swash plate and the second swash plate are attached to the inclined surface of the second swash plate as the second rotating shaft rotates. A plurality of second pistons that reciprocate by sliding contact, and a first cylinder that is built into the valve block and that is switched according to the first rotation and that has the first piston inserted during the forward stroke. The first cylinder port that communicates with the first common liquid flow path. A first switching valve for communicating a first cylinder port, which communicates with a first cylinder into which a first piston is inserted during a reverse stroke, with a second common liquid passage; and a built-in valve block. The second cylinder port communicating with the second cylinder into which the second piston in the backward stroke, which is switched according to the relative rotation with the first rotary shaft, is inserted, is connected to the first common liquid passage. And a second switching valve for communicating a second cylinder port communicating with the second piston into which the second piston is inserted during the forward stroke and the second common liquid flow path. A first annular cavity, which is limited to the block and opens the first cylinder port, and is inserted into the first annular cavity in a liquid-tight manner so that the first annular cavity serves as an outer chamber. Divides into the inner chamber and eccentrically swings in this first annular cavity A first switching valve that selectively communicates the first cylinder port with the outer chamber or the inner chamber, and a second annular cavity that is limited by the valve block and has a second cylinder port opened. And the second annular cavity is slidably mounted in a liquid-tight manner by partitioning the second annular cavity into an outer chamber and an inner chamber, and oscillating eccentrically in the second annular cavity. A second switching valve that selectively communicates the second cylinder port with the outer chamber or the inner chamber, and connects the outer chamber of the first annular cavity with the outer chamber of the second annular cavity. A first common liquid channel, a second common liquid passage that connects the inner chamber of the first annular cavity and the inner chamber of the second annular cavity, and the first common liquid passage One end of the switching valve is abutted at a predetermined interval along the circumferential direction of the switching valve, and A plurality of first drive rods that reciprocally move in a radial direction by penetrating liquid-tightly and slidably through holes provided in the cylinder, and at a predetermined interval along the circumferential direction of the second switching valve. A hydraulic transmission having a plurality of second drive rods, which end-to-end contact with each other, penetrates through a hole provided in the valve block in a liquid-tight manner, and reciprocates in a radial direction. The switching valve of No. 2 is sliding while swinging on the corresponding cylinder port, but the pressure acting on the cylinder port side where the pressure on the cylinder port side acts and the pressure acting on the bottom side of the annular cavity are not the same. As a result, an imbalance in pressure occurs, and the frictional force increases due to the pressure contact and sliding in one direction, which may deteriorate the sliding state, reduce the efficiency, cause wear and seizure.

(Means for Solving the Problem) The present invention has been devised to address this problem, and the gist thereof is to correspond to the above-mentioned first or second circular ring-shaped switching valve. Since the pressure acting on the cylinder port side and the sliding part pressure on the bottom surface of the annular cavity are different, the pressing force is canceled by the unbalance force generated, so that the switching valve is connected between the cylinder port side and the annular cavity side slide. Providing a large number of guide holes through which

(Function) The first and second switching valves are arranged so as to be liquid-tightly slidably arranged on the first and second cylinder port side sliding surfaces and the first and second annular cavity bottom surface sliding surfaces. By providing a large number of connecting holes through both sides of the first and second switching valves, the pressure difference between the two sides is canceled, and the imbalance of the pressure acting on these first and second switching valves is cancelled. The sliding condition is improved by canceling the force caused by.

(Embodiment) One embodiment of the present invention is shown in FIGS. 1, 2, and 3.

 In FIG. 1, 1 is a first rotary shaft and 2 is a second rotary shaft, which are arranged concentrically with the first rotary shaft 1. Reference numeral 3 is a first cylinder barrel, which is connected to the first rotating shaft 1. Reference numeral 4 denotes a second cylinder barrel which is arranged concentrically with the second rotary shaft 2 and rotatable therewith. A valve block 5 is held by the inner end surface of the first cylinder barrel 3 and the inner end surface of the second cylinder barrel 4, and is fixed integrally with these through a pin or the like. In the first cylinder barrel 3, a plurality of cylinders 6 are arranged at predetermined intervals along the circumference of a circle centered on the axis of the first cylinder barrel 3 from the outer end surface of the first cylinder barrel 3 in the direction of the axis thereof. Is growing. First pistons 7 are automatically inserted in the cylinders 6 in a liquid-tight manner, and spherical outer ends of the first pistons 7 are held by slipper pads 8 so that they can be slidably moved. These slipper pads 8 are held by a retainer 9, and the sliding surface thereof is in sliding contact with the inclined surface of the first swash plate 10. The first swash plate 10 is rotatably supported by a casing 12 via a tilting shaft 11 that is orthogonal to the first shaft center. In the second cylinder barrel 4, a plurality of cylinders 13 are arranged at predetermined intervals along a circle centered on the axis of the second cylinder barrel 4 from the outer end surface of the second cylinder barrel 4 substantially in the axial direction. It is growing toward you. A second piston 14 is inserted into each of the cylinders 13 so as to be slidable in a liquid-tight manner, and spherical outer ends of the second pistons 14 are held by a slipper pad 15 so as to be slidable. ing. These slipper pads 15 are held by a retainer 16, and the sliding surface thereof is in sliding contact with the inclined surface of the second swash plate 17. The second swash plate 17 is integrated with the second rotating shaft 2.

The surface of the valve block 5 facing the first cylinder barrel 3 is provided with an annular groove whose center axis is the center, and the groove and the inner end surface of the first cylinder barrel 3 form the cylinder block 5 An annular cavity 60 is limited inside. A ring-shaped groove centered on the axis is provided on the surface facing the second cylinder barrel 4, and the groove and the inner end surface of the second cylinder block 4 form a ring-shaped groove in the valve block 5. The cavity 60 is limited.

At the radial center of the cavity 60 there is a cocoon-shaped opening of the first cylinder port 21, and at the radial center of the cavity 61 there is a cocoon-shaped opening of the second cylinder port 30. The outer end of the cavity 60 in the radial direction is outside the radial direction of the cavity 61 via a large number of first common liquid passages 27 provided in the valve block 5 at predetermined intervals along the circumferential direction. The inner end in the radial direction communicates with the end portion and the outer end in the radial direction of the cavity 61 via the second common liquid flow passage 26 that is drilled in the valve block 5 at a predetermined interval along the circumferential direction. It communicates with the end.

Each oval opening is arranged in the cavity 60, and has an annular shape having a diameter substantially the same as that of the Pitch circle and a thickness substantially the same as the radial dimension of these oval openings. Of the valve block 5 is mounted eccentrically along the tilt axis 11 from the shaft center of the valve block 5 by Δ so as to be slidable in a liquid-tight manner. It is divided into a room and a room.

Similarly, in the cavity 61, there is formed a second annular ring having substantially the same diameter as the pitch circle in which the oval openings are arranged and having a thickness substantially the same as the radial dimension of the oval openings. The directional control valve 23 is mounted so as to be slidable in a liquid-tight manner by eccentricity Δ from the axis of the valve block 5 along the direction of the neutral line of the inclined surface of the second swash plate 17. The cavity 61 is partitioned into an outer chamber and an inner chamber.

The inner ends of a plurality of drive rods 24 of equal length are in contact with the outer peripheral surface of the first switching valve 22 at regular intervals along the circumferential direction, and these drive rods 24 are drilled in the valve block 5. Through a radially extending hole in a liquid-tight manner, and its outer end abuts the inner surface of the cam ring, which is an inner race of the bearing 19.

 Also, the outer ends of a plurality of drive rods 25 of equal length are slidably contacting the inner peripheral surface of the second switching valve 23 along the circumferential direction at predetermined intervals, and these drive rods 25 are attached to the valve block 5. The hole penetrates through the hole in a liquid-tight manner so that its inner end is in sliding contact with the outer surface of the cam ring 28. The valve block 5 and the first cylinder barrel 3 are fastened to each other by a plurality of bolts 62 extending in the axial direction at predetermined intervals in the circumferential direction, and the valve block 5 and the second cylinder barrel 3 are fastened to each other. The barrel 4 is fastened to each other by a plurality of bolts 63 extending in the axial direction at predetermined intervals in the circumferential direction.

 Then, when the first rotary shaft 1 is rotationally driven, the first cylinder barrel 3, the valve block 5 and the cylinder barrel 4 rotate, and along with this, the first piston 7 moves in the first cylinder 6 within the shaft. Reciprocates in the direction. At the same time, the outer ends of the plurality of drive rods 24 roll on the cam surface of the cam ring, and the drive rods 24 reciprocate in the radial direction, so that the first switching valve 22 moves eccentrically in the cavity 60. Then, the elliptical opening of the first cylinder port 21 communicating with the first cylinder 6 into which the first piston 7 in the backward stroke is inserted is opened to the outer chamber and the first piston 7 is inserted in the forward stroke. The oval opening of the first cylinder port 21 communicating with the first cylinder 6 is opened to the inner chamber. In addition, the inner ends of the plurality of drive rods 25 roll on the cylindrical cam surface 28 of the cam ring 28 so that the drive rods 25 reciprocate radially, and the second switching valve 23 has a cavity 61. The second cylinder port 30 communicating with the second cylinder 13 into which the second piston 14 in the forward stroke is inserted by eccentrically oscillating the inside of the second cylinder port 30 is opened to the outer chamber, and the second chamber is opened. The oval opening of the second cylinder port 30 communicating with the second cylinder 13 into which the second piston 14 is inserted is opened in the inner chamber.

Thus, the liquid discharged from the first cylinder 6 in the forward stroke is the first cylinder port 21, the inner chamber of the cavity 60, the second common liquid passage 26, the inner chamber of the cavity 61, the second chamber. It is sucked into the second cylinder 13 during the return stroke through the cylinder port 30. Then, the liquid discharged from the second cylinder 13 in the forward stroke passes through the second cylinder port 30, the outer chamber of the cavity 61, the first cylinder port 21 and the first cylinder in the backward stroke. It is sucked into the cylinder 6. Here, the first switching valve 22 slidingly contacting the first cylinder port 21 has the other one surface slidingly contacting the bottom surface of the annular cavity 60. Is provided.

The second switching valve 23 slidingly contacting the second cylinder port 30 has one other surface slidingly contacting the bottom surface of the annular cavity 61, but the switching valve 23 has a large number of guides penetrating both sliding contacting surfaces. A hole 67 is provided.

(Effect of the device) By providing a large number of guide holes penetrating both the sliding contact surfaces of these first switching valves, the pressures on the cylinder port side and the annular cavity chamber side sliding surface become equal and unbalanced. Since the force is reduced, the sliding condition is improved and it is possible to reduce sliding wear, improve mechanical efficiency, and improve performance. Further, this effect is exactly the same for the second switching valve.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 to 5 show an embodiment, FIG. 1 is a longitudinal sectional view, FIG. 2 is an enlarged view of a switching valve portion, and FIG. 3 is an XX cross section. FIG. 4 shows a ZZ section, and FIG. 5 shows a YY section. 1st rotary shaft ・ 1, 2nd rotary shaft ・ 2, 1st cylinder barrel ・ 3 2nd cylinder barrel ・ 4, valve block ・ 5, 1st cylinder ・ 6, 1st piston ・ 7, 1st swash plate, 10, 2nd cylinder, 13, 2nd piston 14, 2nd swash plate, 17, 1st switching valve, 22, 2nd switching valve, 23, 1st drive rod・ 2 4, second drive rod ・ 25, first common liquid passage ・ 27, second common liquid passage ・ 26, first cam bearing ・ 19, second cam ・ 28, first Annular cavity 60, second annular cavity 61, first switching valve through guide hole 66, second switching valve through guide hole 67, replenishment oil-related passages 43, 44, 45, 46, bearings, 36, 38, 40, 41, 49, cylinder barrel fastening bolts, 62, 63, casing - 12, 33, retail Na 9, 16, Suritsupapatsudo-8, 15

Claims (1)

[Claims] 1. A first rotating shaft and the same as the first rotating shaft. The second rotating shaft arranged on the core and the first rotating shaft A first cylinder barrel connected to the shaft; Concentric with the rotation axis of 2 so that relative rotation is possible The arranged second cylinder barrel and the first cylinder barrel The inner end surface of the cylinder barrel and the second cylinder barrel Is placed between the inner end surface of the Valve block and the first cylinder barrel A circle from its outer end face to a circle centered on its axis Substantially at predetermined intervals along the circumferential direction A plurality of first cylinders extending in the axial direction and stationary Is supported by the casing that is directly connected to the first rotary shaft. Has an inclined surface that can be tilted around the intersecting tilt axis Inside the first swash plate and the first cylinder, respectively. Liquid-tightly inserted so that its outer end is the first Tilt of the first swash plate with rotation of the Linda barrel A plurality of firsts that reciprocate by sliding on a slope    1 piston and the second cylinder barrel A circle from its outer end face on a circle centered on its axis Substantially its axis at a predetermined distance along the direction A plurality of second cylinders extending in the core direction; A second swash plate integrated with the second rotating shaft; Liquid-tightly slidably inserted into each of the two cylinders. The outer end of the shaft is raised by the rotation of the second rotary shaft. By sliding contact with the inclined surface of the second swash plate, A plurality of returning second pistons, and the valve It is built into the block and cuts according to the first rotation above. The first piston, which was replaced and was in the forward stroke, was inserted A first cylinder port communicating with the first cylinder To communicate with the first common liquid flow path, and Communicates with the first cylinder in which the piston of The first cylinder port to the second common liquid passage A first switching valve that communicates with the valve block; Built-in to the relative rotation with the first rotation axis 2nd piston in the return stroke switched according to The second cylinder communicating with the second cylinder in which The binder port is connected to the first common liquid passage.    The second piston is inserted during the forward stroke. Above the second cylinder port communicating with the piston A second switching valve that communicates with the second common liquid flow path; It is equipped with a The first annular cavity where the daport opens and this first It is inserted in the annular cavity of the The annular cavity of 1 is divided into an outer chamber and an inner chamber. By eccentrically sliding within the first annular cavity, 1 cylinder port to the above outer chamber or the above inner chamber A first switching valve for selectively communicating with the valve and the valve described above. The second cylinder port is opened due to the block limit. Inside the second annular cavity where the second annular cavity is spoken Mounted in a liquid-tight manner on the second annular cavity Partition the outer chamber into the inner chamber and this second annular cavity The second cylinder by eccentrically sliding inside Selectively connect the port to the outer chamber or the inner chamber. Of the second switching valve to be passed through and the first annular cavity The outer chamber communicates with the outer chamber of the second annular cavity. In the first common liquid flow path and the first annular cavity The side chamber communicates with the inner chamber of the second annular cavity.    A second common liquid passage, the first cylinder Between the daport side sliding part and the bottom surface of the first annular cavity A switching valve having a plurality of guide holes passing through Cylinder port side sliding portion of No. 2 and the second annular cavity The second having a plurality of conducting holes penetrating between the bottom surfaces A hydraulic transmission having a switching valve.