JP6745772B2 - Variable capacity swash plate type hydraulic rotary machine - Google Patents

Description

The present invention relates to a variable displacement swash plate hydraulic rotary machine that is mounted on a construction machine such as a hydraulic excavator and is preferably used as a variable displacement swash plate hydraulic pump or hydraulic motor.

Generally, a variable displacement type swash plate type hydraulic rotary machine provided in a construction machine such as a hydraulic excavator is, for example, a variable displacement type hydraulic pump which constitutes a hydraulic source together with a tank, or a variable displacement type which constitutes a traveling or turning hydraulic actuator. It is used as a displacement type hydraulic motor or the like.

A variable displacement type swash plate type hydraulic rotating machine according to this type of conventional technology is provided with a swash plate as a variable capacity portion that is tiltably provided in a casing, and a tilting control that is provided in the casing and is externally supplied and discharged. A tilt actuator having a servo piston for tilt-driving the swash plate according to pressure, and a spool provided in the casing for variably controlling the tilt control pressure of the tilt actuator are provided in a control sleeve. A regulator including a servo valve and a feedback link provided between the control sleeve of the regulator and the servo piston to transmit the displacement of the servo piston to the control sleeve are provided (see Patent Documents 1 and 2).

Here, when the swash plate causes high frequency vibration due to the influence of hydraulic pulsation, this vibration is transmitted from the swash plate to the servo piston. Therefore, the feedback link that transmits the displacement of the servo piston to the control sleeve is provided with an elastic link member (expansion spring, clamping spring) using an elastic body such as a spring. Thus, the elastic link member can prevent the vibration of the servo piston from being transmitted to the control sleeve.

International Publication No. 2006/129431 JP, 2003-74460, A

The feedback link according to Patent Document 1 has an expansion spring bent into a U-shape as an elastic link member, and the tip of this expansion spring is always in contact with two side surfaces of a concave groove formed in the servo piston. It is configured. However, for example, when the servo piston is largely displaced in the reverse direction by switching the tilt direction of the swash plate to the reverse direction, the expansion spring may be plastically deformed. This causes a gap (play) between the side surface of the concave groove of the servo piston and the tip of the expansion spring, which causes a problem that the displacement of the servo piston cannot be smoothly transmitted to the control sleeve.

On the other hand, the feedback link according to Patent Document 2 has a sandwiching spring bent into a U shape as an elastic link member, and has a configuration in which an output pin protruding from the servo piston is sandwiched in a radial direction by both ends of the sandwiching spring. There is. However, the elastic link member using the sandwiching spring gradually undergoes plastic deformation during long-term use of the hydraulic rotating machine. Therefore, when the direction of displacement of the servo piston changes, a gap (play) is generated between the output pin and the sandwiching spring, which makes it impossible to smoothly transmit the displacement of the servo piston to the control sleeve. is there.

The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to be able to damp vibrations transmitted from a servo piston to a feedback link and to enhance the durability of the feedback link. Another object of the present invention is to provide a variable displacement type swash plate type hydraulic rotating machine.

In order to solve the problems described above, the present invention provides a tilt actuator having a servo piston that tilts and drives a swash plate according to tilt control pressure supplied and discharged from the outside, and a tilt actuator, A regulator including a servo valve that is provided in the casing and has a spool in a control sleeve for variably controlling the tilt control pressure of the tilt actuator, a control sleeve of the regulator, and a servo piston of the tilt actuator. It is applied to a variable displacement swash plate type hydraulic rotary machine provided with a feedback link which is provided between the two and which is rotated about a rotation fulcrum to transmit the displacement of the servo piston to the control sleeve.

A feature of the present invention is that, in the feedback link, an intermediate portion in the length direction is connected to the rotation fulcrum, a base end side in the length direction is connected to the control sleeve of the regulator, and a tip end side in the length direction is connected. It is configured to include a rigid link that is a free end and is formed of a rigid body that extends in a direction that intersects the servo piston from the outside in the radial direction. The rigid link is formed on the outer peripheral side of the servo piston. Are formed on both sides in the axial direction of the servo piston with the concave groove inserted from the free end side and the concave groove sandwiched therebetween, and one side extending in the axial direction of the servo piston is an open end that opens into the concave groove. The sliding hole having the closed end on the other side, and the sliding hole provided so as to project from both axial sides of the servo piston toward the concave grooves, respectively A pair of clamping members that elastically clamps the rigid link in the groove from both sides in the direction, and a vibration damping unit that suppresses the vibration of the servo piston from being transmitted to the rigid link via the clamping members are provided. It is being done.

According to the present invention, the displacement of the servo piston is transmitted to the rigid link via the pair of holding members, so that the control sleeve of the regulator can follow the displacement of the servo piston. In this case, even if the swash plate vibrates due to hydraulic pressure pulsation and the vibration is transmitted to the servo piston, the vibration of the servo piston can be suppressed from being transmitted to the rigid link by the elasticity of the sandwiching member and the vibration damping portion. Therefore, the feedback link can be configured using a rigid link that is difficult to plastically deform, and the durability of the feedback link can be improved.

FIG. 1 is a vertical sectional view showing a variable displacement swash plate type hydraulic pump according to a first embodiment of the present invention. FIG. 2 is a cross-sectional view of the hydraulic pump as viewed in the direction of arrow II-II in FIG. 1. FIG. 3 is a cross-sectional view of a cylinder block, a tilt actuator, a rigid link, etc. of the hydraulic pump as viewed from the direction of arrows III-III in FIG. FIG. 3 is an exploded perspective view showing a swash plate, a tilt lever, a servo piston, a rigid link, a control sleeve and the like in FIG. 2. It is the top view which looked at a servo piston, a rigid link, a poppet, etc. from the upper side. FIG. 6 is a cross-sectional view of the servo piston, the rigid link, the poppet, and the vibration damping portion as viewed in the direction of arrows VI-VI in FIG. 5. FIG. 6 is a plan view of the same position as FIG. 5 in which the servo piston has moved, as viewed from above. FIG. 8 is a cross-sectional view of the servo piston, the rigid link, the poppet, and the vibration damping portion as viewed in the direction of arrows VIII-VIII in FIG. 7. It is a hydraulic circuit diagram for capacity control of a hydraulic pump. It is sectional drawing of the same position as FIG. 6 which shows the servo piston, the rigid link, the poppet, and the vibration damping part by 2nd Embodiment. It is a perspective view which shows the poppet in FIG. 10 alone.

Hereinafter, a case where the variable displacement swash plate hydraulic rotary machine according to the embodiment of the present invention is applied to a variable displacement swash plate hydraulic pump will be described as an example with reference to the accompanying drawings.

First, FIGS. 1 to 9 show a first embodiment of the present invention. In the figure, a variable displacement type swash plate hydraulic pump 1 (hereinafter referred to as hydraulic pump 1) has a casing 2 that forms an outer shell thereof. The casing 2 is composed of a stepped cylindrical casing body 3 having one end side which is a front bottom portion 3A, and a rear casing 4 provided on the casing body 3 so as to close the other end side of the casing body 3. There is.

As shown in FIG. 2, the casing main body 3 of the casing 2 is provided with an actuator mounting portion 3B at a position separated from the front bottom portion 3A, and the actuator mounting portion 3B projects radially outward of the casing main body 3. .. Then, as shown in FIGS. 2 and 3, a tilt actuator 16, a servo piston 18, etc., which will be described later, are provided in the actuator mounting portion 3B.

An actuator mounting portion 3B of the casing body 3 is provided with a substantially rectangular opening 3C as shown in FIGS. 2 and 3 between the actuator mounting portion 3B and a regulator 24 which will be described later, and a feedback which will be described later is provided in the opening 3C. A rigid link 28 of the link 27 is rotatably attached via a pivot pin 29. Here, the casing body 3 is filled with oil (operating oil), and the servo piston 18, the regulator 24, and the like operate while being immersed in the operating oil inside the casing body 3.

On the other hand, the rear casing 4 of the casing 2 is formed with supply/discharge passages 14, 15 and the like described later, and these supply/discharge passages 14, 15 are introduced into the cylinder 7 through a valve plate 13 described below (operating oil ( Pressure oil).

The rotary shaft 5 is rotatably provided in the casing body 3 of the casing 2. The rotating shaft 5 is rotatably mounted on one side in the axial direction inside the front bottom portion 3A of the casing body 3 via a bearing or the like, and on the other side is rotatably mounted on the rear casing 4 via a bearing or the like. A prime mover of a hydraulic excavator, for example, is connected to one side (projection end side) of the rotary shaft 5 that axially projects from the front bottom portion 3A of the casing body 3 via a power transmission mechanism (not shown) or the like. Thus, the rotary shaft 5 is rotationally driven.

The cylinder block 6 is located inside the casing 2 and is provided on the outer peripheral side of the rotary shaft 5. The cylinder block 6 is provided with a plurality (usually an odd number) of cylinders 7 that are spaced apart in the circumferential direction and extend in the axial direction. The cylinder block 6 is spline-coupled to the outer peripheral side of the rotary shaft 5 and is rotationally driven integrally with the rotary shaft 5.

The plurality of pistons 8 are slidably fitted in the cylinders 7 of the cylinder block 6. Each piston 8 reciprocates in each cylinder 7 by the rotation of the cylinder block 6, sucks hydraulic oil into each cylinder 7 from the valve plate 13 side described later, and discharges this as high pressure oil. is there.

As shown in FIG. 1, the plurality of pistons 8 are at the bottom dead center position where they are largely projected (extended) from the cylinder 7 at a position on the upper side of the rotary shaft 5 and inside the cylinder 7 at a position on the lower side of the rotary shaft 5. It becomes the top dead center position reduced to. Each piston 8 has a suction stroke in which the piston 8 slides and displaces from the top dead center to the bottom dead center and a slide displacement from the bottom dead center to the top dead center while the cylinder block 6 makes one rotation. The discharge stroke to be performed is repeated.

In the intake stroke of the piston 8 corresponding to a half rotation of the cylinder block 6, the working oil is sucked into the cylinder 7 from the side of the supply/discharge passage 15 described later, and the piston 8 corresponding to the remaining half rotation of the cylinder block 6 is discharged. In the stroke, the piston 8 causes the oil liquid in each cylinder 7 to be discharged as high-pressure pressure oil from the supply/discharge passage 14 side described later into the discharge pipeline 47 described later (see FIG. 9).

The plurality of shoes 9 are swingably provided at the projecting end of each piston 8. Each shoe 9 is pressed against a smooth surface 11A of a swash plate 11 described later by the pressing force (hydraulic pressure) from the piston 8. Then, each shoe 9 rotates together with the rotary shaft 5, the cylinder block 6 and the piston 8 in this state to slide on the smooth surface 11A so as to draw a ring-shaped locus.

The swash plate support 10 is provided on the front bottom portion 3A of the casing body 3. As shown in FIGS. 1 and 2, the swash plate support 10 is arranged on the back side of the swash plate 11 around the rotary shaft 5 and is fixed to the front bottom portion 3A of the casing body 3. A pair of tilt sliding surfaces 10A for tiltably supporting the swash plate 11 are formed on the swash plate support body 10 as concave curved surfaces, and each tilt sliding surface 10A is shown in FIG. As described above, the rotary shaft 5 is sandwiched between the left and right (or upper and lower) portions.

The swash plate 11 is tiltably provided in the casing 2. The swash plate 11 is attached to the front bottom portion 3A side of the casing body 3 via the swash plate support 10, and the surface side thereof is a smooth surface 11A as a sliding surface. An insertion hole 11B is formed in the center of the swash plate 11, and the rotary shaft 5 is inserted through the insertion hole 11B with a gap.

Here, the swash plate 11 constitutes a capacity variable portion of the hydraulic pump 1, and the back side of the swash plate 11 is tiltably abutted on each tilt sliding surface 10A of the swash plate support 10. .. The swash plate 11 is tilt-driven by the tilt actuator 16 in the directions A and B shown in FIGS.

The tilt lever 12 is integrally formed on a side portion of the swash plate 11. The tilting lever 12 extends from the side of the swash plate 11 toward the servo piston 18, as shown in FIGS. A projecting pin 12A is integrally provided on the tip end side of the tilt lever 12, and the servo piston 18 is connected to the projecting pin 12A via a slide plate 23 described later.

The valve plate 13 is fixedly provided on the rear casing 4 and constitutes a switching valve plate that is in sliding contact with the end surface of the cylinder block 6. Therefore, as shown in FIG. 2, the valve plate 13 is formed with a pair of supply/discharge ports 13A and 13B extending around the rotary shaft 5 in an eyebrow shape. Of these supply/discharge ports 13A and 13B, for example, the supply/discharge port 13A is a high-pressure side discharge port, and the supply/discharge port 13B is a low-pressure side suction port.

The pair of supply/discharge passages 14 and 15 are formed in the rear casing 4. The supply/discharge passage 14 on the high pressure side of the pair of supply/discharge passages 14 and 15 is connected to, for example, a discharge pipeline 47 described later shown in FIG. 9, and the supply/discharge passage 15 on the low pressure side is connected to a tank 41 described later. It is something. The supply/discharge passage 14 on the high pressure side communicates with the supply/discharge port 13A of the valve plate 13, and the supply/discharge passage 15 on the low pressure side communicates with the supply/discharge port 13B.

When the rotary shaft 5 is rotationally driven in the casing 2, the pistons 8 reciprocate in the respective cylinders 7 as the cylinder block 6 rotates, and these pistons 8 are actuated into the cylinders 7 from the supply/discharge passage 15 side. The pressure oil is discharged to the supply/discharge passage 14 side while sucking the oil.

The tilt actuator 16 is provided in the actuator mounting portion 3B of the casing body 3. As shown in FIGS. 2 and 3, the tilt actuator 16 has cylinder holes 17A and 17B as tilt control cylinders formed on the actuator mounting portion 3B of the casing body 3 located radially outside the cylinder block 6. , And a servo piston 18 slidably fitted in the cylinder holes 17A, 17B. The tilt actuator 16 tilts and drives the swash plate 11 in directions A and B indicated by arrows by a servo piston 18.

The servo piston 18 is provided on the actuator mounting portion 3B of the casing body 3. The servo piston 18 is formed as a stepped piston including a large diameter portion 18A and a small diameter portion 18B as shown in FIG. The large diameter portion 18A of the servo piston 18 is slidably inserted into the cylinder hole 17A of the actuator mounting portion 3B, and the small diameter portion 18B is slidably inserted into the cylinder hole 17B.

Here, the large-diameter portion 18A of the servo piston 18 defines a large-diameter hydraulic chamber 19A in the cylinder hole 17A as shown in FIG. 3, and the hydraulic chamber 19A is defined by the cover plate 20A. It is blocked from the outside. On the other hand, the small diameter portion 18B of the servo piston 18 defines a small diameter hydraulic chamber 19B in the cylinder hole 17B, and the hydraulic chamber 19B is closed from the outside of the cylinder hole 17B by a cover plate 20B.

When the tilt control pressure is supplied to and discharged from the control pressure lines 43 and 44 (see FIG. 9) described later in the hydraulic chambers 19A and 19B, the tilt actuator 16 operates the servo piston 18 according to the tilt control pressure at this time. The cylinder holes 17A and 17B are slidably displaced in the axial direction. Further, the axial displacement of the servo piston 18 is transmitted from the slide plate 23 to the swash plate 11 via the tilt lever 12, so that the swash plate 11 follows the servo piston 18 and is in the directions A and B shown by the arrows. It is driven to tilt.

The groove 21 is formed on the outer peripheral side of the large diameter portion 18A of the servo piston 18. The recessed groove 21 is a notched groove having a U-shaped cross section formed by partially cutting out the outer peripheral side of the large-diameter portion 18A as shown in FIGS. 3 to 5, and a rigid link 28 described later has a free end. It is inserted from the 28D side. The concave groove 21 is arranged at a position facing a later-described engaging groove 22 in the radial direction (upper and lower) of the large diameter portion 18A.

Here, as shown in FIGS. 5 to 8, the concave groove 21 has a parallel groove portion 21A extending in a direction crossing (orthogonal to) the axis O1-O1 of the servo piston 18, and a taper shape from the end portion of the parallel groove portion 21A. The taper groove portion 21B is formed by expanding. The parallel groove portion 21A of the concave groove 21 is formed to have a smaller dimension in the groove width direction (axial direction of the servo piston 18) than an engaging groove 22 described later. The parallel groove portion 21A of the concave groove 21 has side wall surfaces 21A1 and 21A2 on both sides in the groove width direction, and the side wall surfaces 21A1 and 21A2 are provided with sliding holes 31 and 32 to be described later, respectively.

On the other hand, the taper groove portion 21B of the concave groove 21 contacts an intermediate portion of the rigid link 28 with each side wall surface 21A1, 21A2 of the concave groove 21 when the servo piston 18 is axially displaced along the axis O1-O1. It also has the function of preventing interference.

The engagement groove 22 is provided in the large diameter portion 18A of the servo piston 18. As shown in FIGS. 2 to 4, the engaging groove 22 is formed as a parallel groove having a U-shaped cross section at a position facing the concave groove 21 in the radial direction. A slide plate 23 is slidably mounted in the engagement groove 22 in order to transmit the axial displacement of the servo piston 18 to the swash plate 11 via the tilt lever 12.

The slide plate 23 is slidably fitted in the engagement groove 22 of the servo piston 18. The slide plate 23 is formed as a substantially rectangular plate as shown in FIG. 4, and slides (sliding displacement) in the engagement groove 22 in a direction traversing the servo piston 18. An engaging hole 23A is formed in the center of the slide plate 23, and a protruding pin 12A of the tilt lever 12 is rotatably fitted in the engaging hole 23A.

That is, the slide plate 23 is mounted in the engagement groove 22 of the servo piston 18 in a state where the protruding pin 12A of the tilting lever 12 is fitted in the engagement hole 23A in advance. In this state, the slide plate 23 transmits the axial displacement of the servo piston 18 to the swash plate 11 via the tilting lever 12, whereby the swash plate 11 follows the servo piston 18 and the arrow A, It is tilt-driven in the B direction.

The regulator 24 is provided in the casing body 3 and variably controls the tilt control pressure supplied to and discharged from the tilt actuator 16. The regulator 24 has a valve case 24A that is detachably provided on the side of the actuator mounting portion 3B, and the valve case 24A covers the opening 3C provided in the actuator mounting portion 3B of the casing body 3 from the outside. (See Figure 2). A sleeve sliding hole (not shown) into which the control sleeve 25 is slidably inserted is formed in the valve case 24A of the regulator 24, and the spool 26 is slidably inserted into the control sleeve 25. Has been done.

That is, the regulator 24 is configured as a hydraulic servo valve having the spool 26 in the control sleeve 25 as shown in FIG. A valve spring 26A is provided at one end of the spool 26, and a hydraulic pilot portion 26B is provided at the other end of the spool 26. The hydraulic pilot section 26B is connected to a pilot line 45 described later via a pressure control valve 46.

On the other hand, in the control sleeve 25, a notch portion 25A located on one side in the axial direction and extending in an arc shape in the circumferential direction and engaged with an engagement pin 30 described later, and an axial direction from the notch portion 25A. A plurality of oil holes 25B, 25C, 25D, etc., which are separated from each other and penetrate in the radial direction of the control sleeve 25, are provided (see FIG. 4).

The control sleeve 25 extends in the axial direction in a state of being substantially parallel to the axis O1-O1 of the servo piston 18, and is displaced (feedback control) in the axial direction by a feedback link 27 described later. Further, the oil holes 25B, 25C, 25D of the control sleeve 25 are connected to a tank 41, control pressure pipe lines 42, 43, etc., which will be described later with reference to FIG.

Next, the feedback link 27, the sliding holes 31 and 32, the poppets 34 and 35, and the vibration damping portions 38 and 39 used in the first embodiment will be described.

The feedback link 27 is provided between the control sleeve 25 of the regulator 24 and the servo piston 18. The feedback link 27 is rotated about a rotation fulcrum in accordance with the displacement of the servo piston 18 to follow the tilting movement of the swash plate 11 and feedback-control the regulator 24. The feedback link 27 is configured to include a rigid body link 28 described later, a pivot pin 29 as a fulcrum of rotation, and an engagement pin 30.

The rigid link 28 is provided between the servo piston 18 and the control sleeve 25 of the regulator 24, and extends substantially parallel to the tilt lever 12. The rigid link 28 is made of a rigid material such as steel and formed as a rigid body that is unlikely to undergo plastic deformation, and transmits the displacement of the servo piston 18 to the control sleeve 25 of the regulator 24. Here, a pin hole 28A penetrating in the upward and downward directions is formed in a middle portion (intermediate portion) in the length direction of the rigid link 28, and the pin hole 28A has a pivot pin 29 as a fulcrum of rotation. Has been inserted. As shown in FIG. 2, the pivot pin 29 is mounted in the opening 3C of the actuator mounting portion 3B, and the rigid link 28 is rotatable around the pivot pin 29 in the opening 3C of the actuator mounting portion 3B. Installed.

The lengthwise base end side (control sleeve 25 side) of the rigid link 28 is a pair of bifurcated pin support portions 28B and 28C (see FIG. 4) for supporting both ends of an engagement pin 30 described later. ) Is integrally formed. Both ends of the engagement pin 30 are fixed to the respective pin support portions 28B and 28C by means of press fitting or the like, and the pin support portions 28B and 28C support the engagement pin 30 in a double-supported state. Then, the proximal end side of the rigid link 28 is connected to the control sleeve 25 via the engagement pin 30 by engaging the notch portion 25A of the control sleeve 25 with the axially intermediate portion of the engagement pin 30. There is.

Therefore, when the rigid link 28 is rotated (swinged) about the pivot pin 29, the engagement pin 30 transmits the movement of the rigid link 28 to the control sleeve 25. As a result, the feedback link 27 axially slides and displaces the control sleeve 25 within the valve case 24A of the regulator 24.

On the other hand, the tip end side (servo piston 18 side) in the length direction of the rigid link 28 is a free end 28D that rotates around the pivot pin 29. The free end 28D linearly extends in a direction intersecting with the axis O1-O1 of the servo piston 18 from the outside in the radial direction, and the tip of the free end 28D is a wedge portion 28E formed in a wedge shape. Of the free end 28D of the rigid link 28, the surfaces of the concave groove 21 (parallel groove portion 21A) formed in the servo piston 18 that face the side wall surfaces 21A1 and 21A2 are poppet contact surfaces 28F and 28G. A pair of poppets 34 and 35 described later are always in contact with the 28F and 28G.

The sliding holes 31 and 32 are formed so as to be coaxial with each other on both sides in the axial direction of the servo piston 18 with the concave groove 21 interposed therebetween. That is, the one sliding hole 31 is provided on the side wall surface 21A1 side of the concave groove 21 (parallel groove portion 21A). The sliding hole 31 is formed as a bottomed hole extending along the axis O1-O1 of the servo piston 18 (axial direction of the servo piston 18), and the poppet 34 described later is slidably inserted therein.

One side in the length direction of the sliding hole 31 is an opening end 31A opened in the concave groove 21, and the other side in the length direction of the sliding hole 31 is a closed end 31B that serves as a hole bottom. A flat plate-shaped spring seat 31C is arranged at the closed end 31B of the sliding hole 31, and the base end of a spring member 36 described later is received by this spring seat 31C.

The other sliding hole 32 is provided on the side wall surface 21A2 side of the concave groove 21 (parallel groove portion 21A). The sliding hole 32 is arranged coaxially with the sliding hole 31, and the hole diameter of the sliding hole 32 and the hole diameter of the sliding hole 31 are set to be equal. The sliding hole 32 extends along the axis O1-O1 of the servo piston 18 (axial direction of the servo piston 18) and penetrates between the axial end surface 18A1 and the side wall surface 21A2 of the large diameter portion 18A of the servo piston 18. ing. A poppet 35, which will be described later, is slidably fitted in the sliding hole 32.

One end of the sliding hole 32 in the length direction (axial direction of the servo piston 18) is an opening end 32A that is open in the groove 21. The other side of the sliding hole 32 in the longitudinal direction is liquid-tightly sealed by a plug (sealing plug) 33, and the tip of the plug 33 is a closed end 32B of the sliding hole 32. A flat plate-shaped spring seat 32C is arranged at the closed end 32B of the sliding hole 32, and the spring seat 32C receives the base end of a spring member 37 described later. In this case, the distance from the opening end 31A of the sliding hole 31 to the spring seat 31C and the distance from the opening end 32A of the sliding hole 32 to the spring seat 32C are set to be equal.

Poppets 34 and 35 as a pair of holding members are slidably inserted and fitted in the sliding holes 31 and 32, respectively. As shown in FIGS. 5 and 6, the poppets 34 and 35 are formed in the same bullet shape, and the tips 34A and 35A of the poppets 34 and 35 are formed in a hemispherical shape. The tip 34A of the poppet 34 projects into the groove 21 from the opening end 31A of the sliding hole 31 and abuts on the poppet abutment surface 28F of the rigid link 28. Here, by making the tip end 34A of the poppet 34 into a hemispherical shape, the poppet 34 always contacts the poppet contact surface 28F even when the rigid link 28 swings, and the load from the rigid link 28 acts uniformly. Has become. Further, the poppet 34 is formed with a cylindrical spring accommodating portion 34B whose base end side is open, and a spring member 36 described later is disposed in the spring accommodating portion 34B.

The tip 35A of the poppet 35 projects into the groove 21 from the opening end 32A of the sliding hole 32, and abuts on the poppet abutment surface 28G of the rigid link 28. Here, by making the tip 35A of the poppet 35 into a hemispherical shape, the poppet 35 is always in contact with the poppet contact surface 28G even when the rigid link 28 swings, and the load from the rigid link 28 acts uniformly. Has become. Further, the poppet 35 is formed with a cylindrical spring accommodating portion 35B having an opening at the base end side, and a spring member 37 described later is arranged in the spring accommodating portion 35B.

The spring member 36 is located in a damper chamber 38A described later, and is provided between the spring seat 31C of the sliding hole 31 and the spring accommodating portion 34B of the poppet 34. The spring member 36 is formed of a compression coil spring, the base end of the spring member 36 abuts on the spring seat 31C, and the tip end of the spring member 36 abuts on the poppet 34 in the spring accommodating portion 34B of the poppet 34. The spring member 36 elastically presses the poppet 34 toward the rigid link 28.

The spring member 37 is located in a damper chamber 39A described later, and is provided between the spring seat 32C of the sliding hole 32 and the spring accommodating portion 35B of the poppet 35. The spring member 37 is formed of the same compression coil spring as the spring member 36. The base end of the spring member 37 abuts the spring seat 32C, and the tip end of the spring member 37 is in the spring accommodating portion 35B of the poppet 35 in the poppet 35. Is in contact with. The spring member 37 elastically presses the poppet 35 toward the rigid link 28.

Here, the lengths of the spring members 36 and 37 are such that the rigid link 28 is removed from the concave groove 21 of the servo piston 18 (the rigid link 28 is removed in FIG. 5), and the tip ends 34A of the poppets 34 and 35. , 35A are set to a length such that they are in contact with each other at the center of the groove 21 in the groove width direction. Then, with the tips 34A, 35A of the poppets 34, 35 in contact with each other at the center of the groove 21 in the groove width direction, the wedge-shaped portion 28E of the rigid link 28 is inserted between the tips 34A, 35A of the poppets 34, 35. .. As a result, as shown in FIG. 5, the free end 28D of the rigid link 28 is arranged at the center of the groove 21 in the groove width direction, and the tips 34A, 35A of the poppets 34, 35 are positioned at the poppet contact surface of the rigid link 28. It is configured to abut against 28F and 28G with an appropriate elastic force. In this case, the rigid link 28 can be easily inserted from the free end 28D side between the distal ends 34A, 35A of the poppets 34, 35 by forming the free end 28D of the rigid link 28 with the wedge-shaped portion 28E.

The vibration damping portion 38 is provided between the sliding hole 31 and the poppet 34, and the vibration damping portion 39 is provided between the sliding hole 32 and the poppet 35. These vibration damping portions 38 and 39 are connected to the rigid link via the poppets 34 and 35 when the vibration of the servo piston 18 is transmitted to the servo piston 18 from the swash plate 11 due to hydraulic pulsation during the operation of the hydraulic pump 1. It suppresses (attenuates) transmission to 28.

The vibration damping portion 38 is composed of a damper chamber 38A formed between the closed end 31B of the sliding hole 31 and the poppet 34, and a throttle passage 38B provided in the servo piston 18 in a state of communicating with the damper chamber 38A. Has been done. Here, a spring member 36 that presses the poppet 34 toward the rigid link 28 is provided in the damper chamber 38A. The throttle passage 38B is formed as an oil hole having a diameter sufficiently smaller than that of the sliding hole 31, and communicates the inside and outside of the damper chamber 38A between the spring seat 31C and the poppet 34.

In this case, since the servo piston 18 is immersed in the hydraulic oil filled in the casing body 3, the hydraulic oil is filled (accommodated) inside and outside the damper chamber 38A. Therefore, as the poppet 34 slides in the sliding hole 31, the working oil flows into the damper chamber 38A through the throttle passage 38B or flows out of the damper chamber 38A. As described above, the elastic force of the spring member 36 pressing the poppet 34 against the poppet contact surface 28F of the rigid link 28 (free end 28D) and the hydraulic oil flowing into and out of the damper chamber 38A through the throttle passage 38B. Due to the throttling action, the vibration transmitted from the servo piston 18 to the rigid link 28 via the poppet 34 can be damped.

The vibration damping portion 39 includes a damper chamber 39A formed between the closed end 32B of the sliding hole 32 and the poppet 35, and a throttle passage 39B provided in the servo piston 18 in a state of communicating with the damper chamber 39A. Has been done. Here, a spring member 37 for pressing the poppet 35 toward the rigid link 28 is provided in the damper chamber 39A. The throttle passage 39B is formed as an oil hole having a diameter sufficiently smaller than that of the sliding hole 32, and connects the inside and the outside of the damper chamber 39A between the spring seat 32C and the poppet 35.

In this case, since the working oil is filled (accommodated) inside and outside the damper chamber 39A, as the poppet 35 slides in the sliding hole 32, the working oil passes through the throttle passage 39B and passes through the damper chamber 39B. It flows into the interior of 39A or flows out of the damper chamber 39A. Thus, the elastic force of the spring member 37 that presses the poppet 35 against the poppet contact surface 28G of the rigid link 28 (free end 28D) and the hydraulic oil flowing into and out of the damper chamber 39A through the throttle passage 39B. Due to the throttling action, the vibration transmitted from the servo piston 18 to the rigid link 28 via the poppet 35 can be damped.

Next, the displacement control hydraulic circuit of the hydraulic pump 1 will be described with reference to FIG.

The pilot pump 40 constitutes a low pressure hydraulic source together with the tank 41. The pilot pump 40 sucks hydraulic oil from the tank 41 and discharges pressure oil for tilt control (tilt control pressure) into the control pressure conduit 42. In this case, the control pressure line 42 communicates with and is disconnected from another control pressure line 43 via the regulator 24, and this control pressure line 43 is connected to the hydraulic chamber 19A of the tilt actuator 16. The pressure of the pressure oil discharged from the pilot pump 40 is kept sufficiently lower than the discharge pressure of the hydraulic pump 1 by a low pressure leaf valve (not shown) or the like.

Here, when the pilot pressure supplied to the hydraulic pilot portion 26B becomes smaller than the biasing force of the valve spring 26A, the regulator 24 switches from the neutral position (a) shown in FIG. 9 to the switching position (b) by the valve spring 26A. To be When the regulator 24 is switched to the switching position (b), the pilot pump 40 is connected to the hydraulic chamber 19A of the tilt actuator 16 via the control pressure lines 42 and 43, and tilt control from the pilot pump 40 is performed. Pressure is supplied into the hydraulic chamber 19A.

Further, when the pilot pressure supplied to the hydraulic pilot portion 26B becomes larger than the biasing force of the valve spring 26A, the regulator 24 resists the valve spring 26A and shifts from the neutral position (a) shown in FIG. 9 to the switching position (c). Is switched to. Then, when the regulator 24 is switched to the switching position (c), the control pressure conduit 43 is connected to the tank 41, so that the pressure oil is discharged from the hydraulic chamber 19A of the tilt actuator 16 to the tank 41, and the liquid is discharged. The pressure inside the pressure chamber 19A drops to a pressure close to the tank pressure.

Another control pressure line 44 branches off from an intermediate portion of the control pressure line 42. The tip end side of the control pressure line 44 is always connected to the hydraulic chamber 19B of the tilt actuator 16. The control pressure line 44 supplies the tilt control pressure from the pilot pump 40 to the hydraulic chamber 19B.

The pilot line 45 branches off from an intermediate portion of the control pressure line 42. The pilot conduit 45 is provided between the hydraulic pilot portion 26B of the regulator 24 and the pilot pump 40, and connects the discharge side of the pilot pump 40 to the hydraulic pilot portion 26B via a pressure control valve 46 described later. ..

The pressure control valve 46 is provided in the middle of the pilot conduit 45. The pressure control valve 46 is composed of an electromagnetic control valve having an electromagnetic proportional solenoid portion 46A. The pressure control valve 46 variably controls the pilot pressure supplied to the hydraulic pilot section 26B of the regulator 24 by the electromagnetic proportional solenoid section 46A.

The discharge pipe line 47 is provided on the discharge side of the hydraulic pump 1. The discharge pipe line 47 connects the supply/discharge passage 14 shown in FIGS. 1 and 2 to an external hydraulic actuator (not shown) or the like. A pressure sensor (not shown) that detects the discharge pressure of the hydraulic pump 1 is provided in the middle of the discharge pipe line 47.

Here, the pressure in the discharge conduit 47 is output as a command signal to the electromagnetic proportional solenoid section 46A of the pressure control valve 46 via this pressure sensor. Then, the pressure control valve 46 increases or decreases the pilot pressure supplied to the hydraulic pilot unit 26B of the regulator 24 in accordance with a command signal output to the electromagnetic proportional solenoid unit 46A (for example, pressure change in the discharge pipe line 47). It is what makes me.

The displacement control hydraulic circuit of the hydraulic pump 1 according to the first embodiment has the above-described configuration. Next, the displacement control operation will be described.

First, while the command signal output to the electromagnetic proportional solenoid portion 46A of the pressure control valve 46 is kept substantially constant, the spool 26 of the regulator 24 is held at the neutral position (a) as shown in FIG. The swash plate 11 of the pump 1 is kept at a substantially constant tilt angle by the tilt actuator 16.

In this state, when a command signal for increasing the tilt angle of the swash plate 11 is output to the electromagnetic proportional solenoid section 46A, the pilot pressure supplied to the hydraulic pilot section 26B of the regulator 24 is changed by the pressure control valve 46. Rise. Therefore, the spool 26 of the regulator 24 is switched from the neutral position (a) to the switching position (c) against the valve spring 26A, and the control pressure line 43 is connected to the tank 41.

As a result, in the tilt actuator 16, the pressure oil in the hydraulic chamber 19A is discharged to the tank 41 side, and the tilt control pressure is supplied from the control pressure line 44 into the hydraulic chamber 19B. Due to the pressure difference between the hydraulic chambers 19A and 19B is slidably displaced in the direction of arrow A, and the swash plate 11 of the hydraulic pump 1 is driven to the large tilt side.

At this time, the control sleeve 25 of the regulator 24 is displaced in the arrow C direction in FIG. 9 about the pivot pin 29 by the movement of the servo piston 18 being transmitted via the rigid link 28. In this way, the regulator 24 is feedback-controlled so that the control sleeve 25 is slidably displaced in the same direction as the spool 26.

Then, when the tilt angle of the swash plate 11 becomes an angle corresponding to the large tilt command by the command signal, the displacement of the control sleeve 25 causes the regulator 24 to return to the neutral position (a), and the hydraulic pressure. The discharge amount of the pressure oil by the pump 1 becomes a large discharge amount corresponding to the command signal, and the capacity control is performed.

On the other hand, when the command signal for reducing the tilt angle of the swash plate 11 is output to the electromagnetic proportional solenoid section 46A, the pilot pressure supplied to the hydraulic pilot section 26B of the regulator 24 is reduced by the pressure control valve 46. .. Therefore, the spool 26 of the regulator 24 is switched from the neutral position (a) to the switching position (b) by the valve spring 26A, and the pilot pump 40 is controlled by the pilot pump 40 via the control pressure lines 42 and 43. 19A is connected.

As a result, the tilt actuator 16 is supplied with the tilt control pressure from the pilot pump 40 to the hydraulic chambers 19A and 19B, and the servo piston 18 is indicated by the arrow B according to the pressure receiving area difference between the hydraulic chambers 19A and 19B. As a result, the swash plate 11 of the hydraulic pump 1 is driven toward the small tilt side.

At this time, the control sleeve 25 of the regulator 24 is displaced in the arrow D direction in FIG. 9 about the pivot pin 29 by the movement of the servo piston 18 being transmitted via the feedback link 27. In this way, the regulator 24 is feedback-controlled so that the control sleeve 25 is slidably displaced in the same direction as the spool 26.

When the tilt angle of the swash plate 11 becomes the angle corresponding to the small tilt command by the command signal, the displacement of the control sleeve 25 causes the regulator 24 to return to the neutral position (a), and the hydraulic pressure is increased. The discharge amount of the pressure oil by the pump 1 becomes a small discharge amount corresponding to the command signal, and the capacity control is performed.

Here, the movement of the feedback link 27 following the servo piston 18 of the tilt actuator 16 will be described in detail.

First, when the spool 26 of the regulator 24 is held at the neutral position (a) as shown in FIG. 9 and the swash plate 11 of the hydraulic pump 1 is kept at a constant tilt angle, the servo piston 18 stops. There is. Therefore, the rigid link 28 of the feedback link 27 and the control sleeve 25 of the regulator 24 are also stopped.

In this state, when the swash plate 11 causes high frequency vibration due to hydraulic pulsation of the hydraulic pump 1 or the like, the vibration of the swash plate 11 is transmitted to the servo piston 18 via the tilt lever 12, the slide plate 23, and the like.

At this time, the poppet 34 that abuts the poppet abutting surface 28F of the rigid link 28 moves finely in the axial direction following the vibration of the servo piston 18 as the spring member 36 repeats fine expansion and contraction (deflection). Vibrate. When the poppet 34 moves in the sliding hole 31 in the axial direction, the hydraulic oil flows out to the damper chamber 38A of the vibration damping portion 38 provided between the sliding hole 31 and the poppet 34 through the throttle passage 38B. To enter. Therefore, the vibration of the poppet 34 is damped by the expansion and contraction of the spring member 36 and the throttle action when the hydraulic oil flows through the throttle passage 38B.

Similarly, the poppet 35 that abuts against the poppet abutment surface 28G of the rigid link 28 repeats the fine expansion and contraction (deflection) of the spring member 37, so that the poppet 35 follows the vibration of the servo piston 18 and becomes fine in the axial direction. Move (vibrate). When the poppet 35 moves in the sliding hole 32 in the axial direction, the hydraulic oil flows out through the throttle passage 39B into the damper chamber 39A of the vibration damping portion 39 provided between the sliding hole 32 and the poppet 35. To enter. Therefore, the vibration of the poppet 35 is damped by the expansion and contraction of the spring member 37 and the throttle action when the hydraulic oil flows through the throttle passage 39B.

In this way, the spring members 36 and 37 expand and contract (bend) in response to the vibration of the servo piston 18, and the hydraulic oil flows into and out of the damper chambers 38A and 39A through the throttle passages 38B and 39B of the vibration damping units 38 and 39. Since the vibration of the poppets 34 and 35 is damped by the throttling action at this time, the vibration transmitted from the servo piston 18 to the rigid link 28 can be damped. As a result, it is possible to prevent the rigid link 28 made of a rigid material from repeating vibrations and improve its durability.

Next, for example, when the tilt angle of the swash plate 11 is switched to the large tilt, when the servo piston 18 is displaced in the arrow A direction from the position shown in FIG. 5 to the position shown in FIG. By moving into the sliding hole 31 against the spring member 36, it collides with the spring seat 31C. As a result, the rigid link 28 swings around the pivot pin 29, and the swing of the rigid link 28 is transmitted to the control sleeve 25 of the regulator 24. In this case, since the rigid link 28 is made of a rigid material, even if the displacement direction of the servo piston 18 changes when the swash plate 11 is tilted, the rigid link 28 is prevented from being plastically deformed. be able to. As a result, the rigid link 28 can swing about the pivot pin 29 while smoothly following the displacement of the servo piston 18, so that the displacement of the servo piston 18 is transferred to the control sleeve 25 via the feedback link 27. I can tell you exactly.

Then, when the swash plate 11 largely tilts and the servo piston 18 stops at a predetermined position, the poppet 34 projects from the opening end 31A of the sliding hole 31 due to the expansion of the spring member 36, and the poppet 34 of the rigid link 28. The contact surface 28F is pressed. On the other hand, the poppet 35 arranged on the opposite side of the poppet 34 with the rigid link 28 interposed therebetween moves into the sliding hole 32 against the spring member 37. As a result, the rigid link 28 returns to the position where the elastic forces of the spring members 36 and 37 are balanced, that is, the central position in the groove width direction of the concave groove 21 shown in FIG.

At this time, as the poppet 34 moves in a direction projecting from the opening end 31A of the sliding hole 31, the hydraulic oil flows into the damper chamber 38A of the vibration damping portion 38 from the outside through the throttle passage 38B, and the hydraulic oil flows. The vibration of the poppet 34 is damped by the throttling action when flowing through the throttling passage 38B. On the other hand, as the poppet 35 moves so as to be drawn into the sliding hole 32, the working oil in the damper chamber 39A of the vibration damping portion 39 flows out to the outside through the throttle passage 39B, and the working oil flows through the throttle passage 39B. The vibration of the poppet 35 is damped by the throttling action at this time.

In this way, the hydraulic oil flows into and out of the elastic force of the spring members 36 and 37 acting on the poppets 34 and 35 that sandwich the free end 28D of the rigid link 28, and the damper chambers 38A and 39A of the vibration damping portions 38 and 39. By virtue of the throttling action of the throttling passages 38B and 39B at this time, the vibration of the rigid link 28 can be damped. As a result, the rigid link 28 that has swung to the position shown in FIG. 7 following the movement of the servo piston 18 can gently return to the position shown in FIG. 5 without causing vibration (divergent vibration).

On the other hand, when the tilt angle of the swash plate 11 is switched to the small tilt, when the servo piston 18 is displaced in the B direction which is the direction opposite to the A direction shown by the arrow in FIG. 7, the poppet 35 is moved by the spring member 37. By moving into the sliding hole 32 against the spring, it collides with the spring seat 32C. As a result, the rigid link 28 swings around the pivot pin 29, and the swing of the rigid link 28 is transmitted to the control sleeve 25 of the regulator 24. In this case, since the rigid link 28 is made of a rigid material, the rigid link 28 is plastically deformed even when the tilt angle of the swash plate 11 is switched from the large tilt to the small tilt in the opposite direction. Can be suppressed. As a result, the rigid link 28 can swing about the pivot pin 29 while following the displacement of the servo piston 18 when the swash plate 11 is switched from the large tilt to the small tilt. The displacement can be accurately transmitted to the control sleeve 25 via the feedback link 27.

Then, when the swash plate 11 tilts slightly and the servo piston 18 stops at a predetermined position, the poppet 35 projects from the opening end 32A of the sliding hole 32 due to the expansion of the spring member 37, and the poppet of the rigid link 28. The contact surface 28G is pressed. The poppet 34 moves into the sliding hole 31 against the spring member 36. As a result, the rigid link 28 returns to the position where the elastic forces of the spring members 36 and 37 are balanced, that is, the central position in the groove width direction of the concave groove 21 shown in FIG.

At this time, as the poppet 35 moves in a direction projecting from the opening end 32A of the sliding hole 32, the hydraulic oil flows into the damper chamber 39A of the vibration damping section 39 from the outside through the throttle passage 39B, and the hydraulic oil flows. The vibration of the poppet 35 is damped by the throttling action when the water flows through the throttling passage 39B. Further, as the poppet 34 moves so as to be drawn into the sliding hole 31, the hydraulic oil in the damper chamber 38A of the vibration damping portion 38 flows out to the outside through the throttle passage 38B, and the hydraulic oil flows through the throttle passage 38B. The vibration of the poppet 34 is damped by the throttling action at this time. As a result, the rigid link 28 can gently return to the position shown in FIG. 5 without causing vibration (divergent vibration).

As described above, in the hydraulic pump 1 according to the first embodiment, the vibration transmitted from the servo piston 18 to the rigid link 28 and the spring members 36 and 37 that elastically press the poppets 34 and 35 against the rigid link 28, and the sliding movement. It can be damped by the vibration damping portion 38 provided between the moving hole 31 and the poppet 34 and the vibration damping portion 39 provided between the sliding hole 32 and the poppet 35. Therefore, since the feedback link 27 can be configured by using the rigid link 28 made of a rigid body that is hard to be plastically deformed, compared to the case where the feedback link is configured by using the elastic link member made of an elastic body such as a spring. The durability of the feedback link 27 can be improved. As a result, even when the hydraulic pump 1 is used for a long period of time, it is possible to suppress plastic deformation, damage, etc. of the rigid link 28, and it is possible to improve the reliability of the entire hydraulic pump 1 including the feedback link 27.

Thus, according to the first embodiment, the feedback link 27 that transmits the displacement of the servo piston 18 to the control sleeve 25 of the regulator 24 is configured by using the rigid link 28 made of a rigid body. Further, in the servo piston 18, a concave groove 21 into which the rigid link 28 is inserted from the free end 28D side, a pair of sliding holes 31 and 32 provided so as to sandwich the concave groove 21, and the sliding holes 31, A pair of poppets 34 and 35 that are inserted into 32 to elastically sandwich the rigid link 28 in the groove 21 and the vibration of the servo piston 18 are suppressed from being transmitted to the rigid link 28 via the poppets 34 and 35. Vibration damping units 38 and 39 are provided.

As a result, even if the swash plate 11 vibrates due to hydraulic pressure pulsation and the vibration is transmitted to the servo piston 18, the vibration of the servo piston 18 is transmitted to the rigid link 28. It can be suppressed by the parts 38 and 39. As a result, the feedback link 27 can be configured using the rigid link 28 that is difficult to plastically deform, and the durability of the feedback link 27 can be improved.

In this case, the vibration damping portion 38 communicates with the damper chamber 38A, which is formed between the closed end 31B of the sliding hole 31 and the poppet 34 and in which hydraulic oil is housed, and communicates with the damper chamber 38A. It is constituted by a throttle passage 38B that is formed and through which the hydraulic oil in the damper chamber 38A flows in and out. Further, the vibration damping portion 39 is formed between the closed end 32B of the sliding hole 32 and the poppet 35, and a damper chamber 39A in which hydraulic oil is stored, and is formed in the servo piston 18 in communication with the damper chamber 39A. And a throttle passage 39B through which the hydraulic oil in the damper chamber 39A flows in and out.

As a result, when the poppets 34 and 35 that elastically sandwich the rigid link 28 in the groove 21 of the servo piston 18 move in and out of the sliding holes 31 and 32 in response to the vibration of the servo piston 18, the hydraulic oil is generated. It flows into and out of the damper chambers 38A and 39A through the throttle passages 38B and 39B. Therefore, the vibration transmitted from the servo piston 18 to the rigid link 28 via the poppets 34 and 35 can be attenuated by the throttling action when the hydraulic oil flows through the throttle passages 38B and 39B.

Further, spring members 36, 37 are provided in the damper chambers 38A, 39A to elastically bias the poppets 34, 35 toward the inside of the concave groove 21 so that the rigid link 28 is always held. Therefore, the poppets 34 and 35 can be pressed against the rigid link 28 with an appropriate elastic force, and the vibration transmitted from the servo piston 18 to the rigid link 28 can be attenuated by the expansion and contraction (flexure) of the spring members 36 and 37. it can.

Further, each of the poppets 34 and 35 is formed in a bullet shape in which the tips 34A and 35A that abut the rigid link 28 in the concave groove 21 have a hemispherical shape. As a result, even if the rigid link 28 is displaced, the tips 34A, 35A of the poppets 34, 35 can always contact the poppet contact surfaces 28F, 28G of the rigid link 28, and the load from the rigid link 28 can be applied. It is possible to act uniformly on 34 and 35.

Next, FIG. 10 and FIG. 11 show a second embodiment of the present invention, and the feature of this embodiment is that the throttle passage of the vibration damping portion is provided in the poppet. In addition, in the second embodiment, the same components as those in the first embodiment are designated by the same reference numerals, and the description thereof will be omitted.

In the figure, the servo piston 18' is formed as a stepped piston composed of a large diameter portion 18A and a small diameter portion 18B, like the servo piston 18 according to the first embodiment, and on the outer peripheral side of the large diameter portion 18A. A groove 21 and an engagement groove 22 are provided. Further, sliding holes 31 and 32 into which the poppets 48 and 49 described later are slidably inserted are formed in the side wall surfaces 21A1 and 21A2 of the parallel groove portion 21A of the concave groove 21. However, the servo piston 18' is different from the servo piston 18 according to the first embodiment in that the throttle passages 38B and 39B according to the first embodiment are not formed.

Poppets 48 and 49 as a pair of holding members are provided so as to be slidably fitted in the sliding holes 31 and 32 of the servo piston 18', respectively. Like the poppets 34 and 35 according to the first embodiment, each of the poppets 48 and 49 is formed in a cannonball shape whose tip ends 48A and 49A have a hemispherical shape. The cylindrical spring accommodating portions 48B and 49B are formed. However, each of the poppets 48, 49 is different from the poppets 34, 35 according to the first embodiment in that throttle passages 50B, 51B described later are formed on the outer peripheral surfaces thereof.

The vibration damping section 50 is provided between the sliding hole 31 and the poppet 48, and suppresses (damps) the vibration of the servo piston 18 ′ from being transmitted to the rigid link 28 via the poppet 48. The vibration damping portion 50 includes a damper chamber 50A formed between the closed end 31B of the sliding hole 31 and the poppet 48, and a plurality of throttle passages formed on the outer peripheral surface of the poppet 48 in a state of communicating with the damper chamber 50A. And 50B. Here, as shown in FIG. 11, each throttle passage 50B is formed by a plurality of (for example, three) grooves formed in the outer peripheral surface of the poppet 48 so as to extend in the axial direction. Each throttle passage 50B communicates between the damper chamber 50A and the concave groove 21 of the servo piston 18', and a damping force is generated by a throttle action when hydraulic oil flows into and out of the damper chamber 50A through each throttle passage 50B. ..

The vibration damping portion 51 is provided between the sliding hole 32 and the poppet 49, and suppresses (damps) the vibration of the servo piston 18 ′ from being transmitted to the rigid link 28 via the poppet 49. The vibration damping portion 51 includes a damper chamber 51A formed between the closed end 32B of the sliding hole 32 and the poppet 49, and a plurality of throttle passages formed on the outer peripheral surface of the poppet 49 in a state of communicating with the damper chamber 51A. And 51B. Each throttle passage 51B communicates between the damper chamber 51A and the concave groove 21 like the throttle passage 50B provided in the poppet 48, and when hydraulic oil flows into and out of the damper chamber 51A through each throttle passage 51B. A damping force is generated by the throttling action of.

The hydraulic pump according to the second embodiment has the structure as described above, and its basic operation is not particularly different from that according to the first embodiment.

However, according to the second embodiment, the throttle passages 50B and 51B are provided on the outer peripheral surfaces of the poppets 48 and 49. Therefore, for example, the effect of damping the vibration transmitted from the servo piston 18' to the rigid link 28 can be adjusted by changing the number of the throttle passages 50B and 51B, the groove shape, and the like. Moreover, by providing the throttle passages 50B and 51B on the outer peripheral surfaces of the poppets 48 and 49, the processing for forming the throttle passages 38B and 39B in the servo piston 18 as in the first embodiment can be omitted, and the servo can be omitted. The structure of the piston 18' can be simplified.

In addition, in the embodiment, it is described that the servo piston 18 is immersed in the working oil by filling the inside of the casing body 3 with the working oil. However, the present invention is not limited to this, and at least the servo piston 18 may be immersed in the hydraulic oil depending on the mounting posture of the hydraulic pump 1.

Further, in the embodiment, the case where the swash plate type hydraulic pump 1 is used as the variable displacement swash plate type hydraulic rotating machine has been described as an example. However, the present invention is not limited to this, and may be applied to, for example, a variable displacement type swash plate hydraulic motor.

1 Hydraulic pump (variable displacement type swash plate type hydraulic rotary machine)
2 Casing 5 Rotating shaft 6 Cylinder block 7 Cylinder 8 Piston 9 Shoe 11 Swash plate 11A Smooth surface (sliding surface)
16 Tilt Actuator 18, 18' Servo Piston 21 Recessed Groove 24 Regulator 25 Control Sleeve 26 Spool 27 Feedback Link 28 Rigid Link 29 Pivot Pin (Rotation Support Point)
31, 32 Sliding holes 31A, 32A Open ends 31B, 32B Closed ends 34, 35, 48, 49 Poppets (holding members)
34A, 35A, 48A, 49A Tip 36, 37 Spring member 38, 39, 50, 51 Vibration damping part 38A, 39A, 50A, 51A Damper chamber 38B, 39B, 50B, 51B Throttle passage

Claims (5)

A tilt actuator having a servo piston that tilt-drives a swash plate according to tilt control pressure supplied to and discharged from the outside of the casing, and the tilt control pressure of the tilt actuator is variably controlled. Therefore, a regulator formed of a servo valve provided in the casing and having a spool in a control sleeve, and a regulator provided between the control sleeve of the regulator and the servo piston of the tilt actuator are rotated around a rotation fulcrum. In a variable displacement swash plate hydraulic rotary machine including a feedback link that transmits the displacement of the servo piston to the control sleeve by being moved,
In the feedback link, a midway portion in the length direction is connected to the rotation fulcrum, a base end side in the length direction is connected to the control sleeve of the regulator, and a tip end side in the length direction is a free end. It is configured to include a rigid link made of a rigid body that extends from the outside in the radial direction with respect to the servo piston.
The servo piston includes
A concave groove formed on the outer peripheral side of the servo piston and in which the rigid link is inserted from the free end side,
Sliding holes formed respectively on both sides in the axial direction of the servo piston with the groove in between, one side extending in the axial direction of the servo piston being an open end opening to the groove and the other side being a closed end,
It is provided by being inserted into each of the sliding holes so as to project from both sides in the axial direction of the servo piston toward the respective concave grooves, and the rigid links are provided in the concave grooves from both sides in the axial direction of the servo piston. A pair of clamping members that elastically clamp,
A vibration damping portion that suppresses the vibration of the servo piston from being transmitted to the rigid link via the sandwiching members,
A variable displacement swash plate type hydraulic rotating machine characterized by being provided with. The vibration damping portion is formed between the closed end of the sliding hole and each of the holding members, and a damper chamber in which hydraulic oil is housed, and the vibration damping portion is formed in the servo piston in communication with the damper chamber. The variable displacement swash plate type hydraulic rotary machine according to claim 1, wherein the variable capacity swash plate type hydraulic rotary machine comprises a throttle passage through which hydraulic oil flows in and out of the damper chamber. The vibration damping portion is formed between the closed end of the sliding hole and each of the sandwiching members, and a damper chamber in which hydraulic oil is housed, and is formed in each of the sandwiching members in communication with the damper chamber. 2. The variable displacement swash plate type hydraulic rotating machine according to claim 1, wherein the variable capacity swash plate type hydraulic rotating machine comprises a throttle passage through which hydraulic oil flows in and out of the damper chamber. The damper chamber is provided with a spring member that elastically urges the holding member toward the inside of the groove so as to always hold the rigid link. Variable capacity swash plate type hydraulic rotary machine described. 2. The variable capacity swash plate type hydraulic pressure according to claim 1, wherein each of the holding members is formed as a cannonball-shaped poppet having a hemispherical tip end that abuts the rigid link in the concave groove. Rotating machine.

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