JP2021188532A - Hydraulic rotary machine - Google Patents

Abstract

To improve accuracy of horsepower control of a hydraulic rotary machine.SOLUTION: A piston pump 100 includes a first energizing mechanism 30 that energizes a swash plate 8 according to a control pressure, a second energizing mechanism 40 that energizes the swash plate 8 against the first energizing mechanism 30, and a regulator 50 that controls the control pressure led by the first energizing mechanism 30. The regulator 50 has an outside spring 51a and an inside spring 51b expanding/contracting following tilting of the swash plate 8, a control spool 52 adjusting the control pressure according to the energizing force of the outside spring 51a and the inside spring 51b, and a pressing mechanism 60 pressing the control spool 52 against the energizing force of the outside spring 51a and the inside spring 51b. The pressing mechanism 60 has a pressing piston 61 that presses the control spool 52 by receiving thrust generated due to a signal pressure of a plurality of signal pressure chambers 60a and 60b.SELECTED DRAWING: Figure 1

Description

The present invention relates to a hydraulic rotary machine.

Patent Document 1 describes a first urging means for urging the swash plate in a direction in which the tilt angle of the swash plate increases, and an urging force in the opposite direction to the urging force on the swash plate by the first urging means. A variable displacement hydraulic pump comprising a second urging means acting on the plate is disclosed. The second urging means includes an urging rod slidably arranged on the guide portion of the housing and an urging pin unit having a plurality of urging pins, and the plurality of urging pins correspond to each other. It is configured to urge the urging rod toward the swash plate according to the signal pressure to be applied.

Japanese Unexamined Patent Publication No. 2018-3609

In the hydraulic pump disclosed in Patent Document 1, the urging pin unit has a configuration in which a plurality of urging pins urge the urging rod according to the corresponding signal pressure. Therefore, due to the difference in the magnitude of the signal pressure and the difference in the contact position between the urging pin and the urging rod, the urging rod exerts an urging force from the urging pin unit in a direction inclined with respect to its central axis. I may receive it. In this case, uneven wear between the urging rod and the housing accommodating the urging rod is likely to occur.

The present invention has been made in view of the above problems, and in a hydraulic rotary machine having a pressing mechanism for urging a swash plate according to a signal pressure, it is possible to suppress wear of a control spool by the pressing mechanism. The purpose.

The present invention is a hydraulic rotator, which is a cylinder block that rotates together with a drive shaft, a plurality of cylinders formed in the cylinder block and arranged at predetermined intervals in the circumferential direction of the drive shaft, and slidable in the cylinder. A piston that is inserted into the cylinder to partition the volume chamber, a tiltable swash plate that reciprocates the piston so as to expand or contract the volume chamber, and a sloping plate that is urged according to the controlled pressure supplied. 1 The urging mechanism, the 2nd urging mechanism that urges the swash plate to resist the 1st urging mechanism, and the control pressure guided by the 1st urging mechanism according to the self-pressure of the hydraulic rotary machine. It is equipped with a regulator to control, and the regulator has a urging member that expands and contracts according to the tilt of the swash plate, and a control spool that moves according to the urging force of the urging member to adjust the control pressure. It has a pressing mechanism that presses the spool against the urging force of the urging member, and the pressing mechanism has a signal pressure chamber in which a plurality of signal pressures are guided and a signal pressure chamber in which a plurality of signal pressure chambers are guided. It is characterized by having a pressing member on which a resultant force acts to press the control spool against the urging force of the urging member.

In the present invention, even if the signal pressure is guided to each of the plurality of signal pressure chambers, the thrust generated by each signal pressure acts on the same pressing member as a resultant force, and the control spool is urged by the pressing member. Is pressed against. Therefore, even if there is a difference in the magnitude of the signal pressure, the control spool is pressed by a common pressing member, so the thrust of the signal pressure acts evenly on the control spool along the central axis of the control spool. It will be easier to make it. Therefore, the friction generated in the control spool is reduced, and the wear of the control spool can be suppressed.

Further, in the present invention, the regulator has a housing member in which an accommodating hole for accommodating the pressing member is formed coaxially with the central axis of the control spool, and the accommodating hole is provided in the direction perpendicular to the central axis of the control spool. A guide portion is provided that regulates the movement of the pressing member and guides the movement of the pressing member along the central axis of the control spool.

In the present invention, the urging force acting on the control spool from the pressing member can be more reliably applied along the central axis of the control spool.

Further, in the present invention, the pressing mechanism further has a seating member having a shaft portion protruding in the axial direction of the control spool toward the pressing member, and the shaft portion is inserted into the pressing member to signal pressure together with the shaft portion. A shaft insertion hole forming a chamber is formed.

In the present invention, since the signal pressure chamber is formed by inserting the shaft portion into the shaft portion insertion hole formed in the pressing member, the inclination of the pressing member is suppressed by the shaft portion.

Further, in the present invention, the pressing mechanism is provided along the axial direction of the control spool, and the shaft portion abutting on the end surface of the pressing member on the opposite side to the end surface abutting on the control spool, and the shaft portion into which the shaft portion is inserted are inserted. It also has an intermediate member in which a shaft insertion hole forming a signal pressure chamber is formed.

According to the present invention, the occurrence of wear of the control spool of the hydraulic rotary machine is suppressed.

It is sectional drawing of the hydraulic pressure rotary machine which concerns on embodiment of this invention. It is a figure which shows the structure of the regulator of the hydraulic pressure rotary machine which concerns on embodiment of this invention, and is the enlarged sectional view of the part A in FIG. It is sectional drawing which shows the structure of the pressing mechanism which concerns on 1st modification of embodiment of this invention. It is sectional drawing which shows the structure of the pressing mechanism which concerns on the 2nd modification of embodiment of this invention. It is sectional drawing which shows the structure of the pressing mechanism which concerns on the 3rd modification of embodiment of this invention.

Hereinafter, the hydraulic rotary machine 100 according to the embodiment of the present invention will be described with reference to the drawings.

The hydraulic rotary machine 100 functions as a piston pump capable of supplying hydraulic oil as a hydraulic fluid by rotating the shaft (drive shaft) 1 and reciprocating the piston 5 by an external power. Further, the hydraulic rotary machine 100 functions as a piston motor capable of outputting a rotational driving force by reciprocating the piston 5 by the fluid pressure of hydraulic oil supplied from the outside and rotating the shaft 1. The hydraulic rotary machine 100 may function only as a piston pump or may function only as a piston motor.

In the following description, the case where the hydraulic rotary machine 100 is used as a piston pump is illustrated, and the hydraulic pressure rotary machine 100 is referred to as a “piston pump 100”.

The piston pump 100 is used as a hydraulic supply source for supplying hydraulic oil to an actuator (not shown) such as a hydraulic cylinder that drives a drive target. As shown in FIG. 1, the piston pump 100 includes a shaft 1 rotated by a power source, a cylinder block 2 connected to the shaft 1 and rotated together with the shaft 1, and a case 3 accommodating the cylinder block 2.

The case 3 includes a bottomed cylindrical case body 3a and a cover 3b that seals the open end of the case body 3a and through which the shaft 1 is inserted. The inside of the case 3 communicates with the tank (not shown) through a drain passage (not shown). The inside of the case 3 may communicate with a suction passage (not shown) described later.

A power source (not shown) such as an engine is connected to one end 1a of the shaft 1 protruding to the outside through the insertion hole 3c of the cover 3b. The end portion 1a of the shaft 1 is rotatably supported by the insertion hole 3c of the cover 3b via the bearing 4a. The other end 1b of the shaft 1 is accommodated in a shaft accommodating hole 3d provided at the bottom of the case body 3a, and is rotatably supported via a bearing 4b. Although not shown, at the other end 1b of the shaft 1, a rotating shaft (not shown) of another hydraulic pump (not shown) such as a gear pump driven by a power source together with the piston pump 100 is provided together with the shaft 1. They are coaxially connected so as to rotate.

The cylinder block 2 has a through hole 2a through which the shaft 1 penetrates, and is spline-coupled to the shaft 1 via the through hole 2a. As a result, the cylinder block 2 rotates with the rotation of the shaft 1.

A plurality of cylinders 2b having an opening on one end surface are formed in the cylinder block 2 in parallel with the shaft 1. The plurality of cylinders 2b are formed at predetermined intervals in the circumferential direction of the cylinder block 2. A cylindrical piston 5 for partitioning the volume chamber 6 is reciprocally inserted into the cylinder 2b. The tip end side of the piston 5 protrudes from the opening of the cylinder 2b, and a spherical seat 5a is formed at the tip end portion thereof.

The piston pump 100 includes a shoe 7 rotatably connected to the spherical seat 5a of the piston 5 and slidably contacting the spherical seat 5a, a swash plate 8 to which the shoe 7 slides with the rotation of the cylinder block 2, a cylinder block 2 and a case. A valve plate 9 provided between the bottom of the main body 3a is further provided.

The shoe 7 includes a receiving portion 7a that receives the spherical seat 5a formed at the tip of each piston 5, and a circular flat plate portion 7b that is in sliding contact with the sliding contact surface 8a of the swash plate 8. The inner surface of the receiving portion 7a is formed in a spherical shape and is in sliding contact with the outer surface of the receiving spherical seat 5a. As a result, the shoe 7 can be angularly displaced in all directions with respect to the spherical seat 5a.

The swash plate 8 is supported by the cover 3b so as to be tiltable in order to make the discharge amount of the piston pump 100 variable. The flat plate portion 7b of the shoe 7 comes into surface contact with the sliding contact surface 8a.

The valve plate 9 is a disk member with which the base end surface of the cylinder block 2 is in sliding contact, and is fixed to the bottom of the case body 3a. Although not shown, the valve plate 9 connects a suction port formed in the cylinder block 2 to the volume chamber 6 and a discharge passage formed in the cylinder block 2 to the volume chamber 6. A discharge port and is formed.

The piston pump 100 includes a tilting mechanism 20 that tilts the swash plate 8 according to the fluid pressure, and a regulator 50 that controls the fluid pressure guided by the tilting mechanism 20 according to the tilt angle of the swash plate 8. Further prepare.

The tilting mechanism 20 includes a first urging mechanism 30 that urges the swash plate 8 in a direction in which the tilt angle decreases, and a second urging mechanism 40 in which the swash plate 8 is urged in a direction in which the tilt angle increases. And have. That is, the second urging mechanism 40 urges the swash plate 8 so as to oppose the first urging mechanism 30.

The first urging mechanism 30 has a large-diameter piston 32 that is slidably inserted into the first piston accommodating hole 31 formed in the cover 3b and abuts on the swash plate 8, and the first piston accommodating hole 31 by the large-diameter piston 32. It has a control pressure chamber 33 partitioned inside.

A fluid pressure (hereinafter referred to as “control pressure”) adjusted by the regulator 50 is introduced into the control pressure chamber 33. The large-diameter piston 32 urges the swash plate 8 in a direction in which the tilt angle becomes smaller by the control pressure guided to the control pressure chamber 33.

The second urging mechanism 40 has a small-diameter piston 42 as a control piston that is slidably inserted into the second piston accommodating hole 41 formed in the case body 3a and abuts on the swash plate 8, and a second piston by the small-diameter piston 42. It has a pressure chamber 43 partitioned in the accommodating hole 41.

The small diameter piston 42 has a first sliding portion 42a, a second sliding portion 42b having a smaller outer diameter than the first sliding portion 42a, and an outer diameter difference between the first sliding portion 42a and the second sliding portion 42b. It has a stepped surface 42c formed by the above.

The second piston accommodating hole 41 has a first accommodating portion 41a on which the first sliding portion 42a of the small diameter piston 42 slides, and a second sliding portion 42b having an inner diameter smaller than that of the first accommodating portion 41a. It has two accommodating portions 41b and a stepped surface 41c formed by an inner diameter difference between the first accommodating portion 41a and the second accommodating portion 41b. The first accommodating portion 41a opens inside the case 3. The pressure chamber 43 is partitioned by the outer peripheral surface and the stepped surface 42c of the second sliding portion 42b of the small diameter piston 42, and the inner peripheral surface and the stepped surface 41c of the first accommodating portion 41a of the second piston accommodating hole 41. That is, the pressure chamber 43 is an annular space formed on the outer periphery of the small diameter piston 42.

The discharge pressure (self-pressure) of the piston pump 100 is constantly guided to the pressure chamber 43 through the discharge pressure passage 10 formed in the case body 3a. The small-diameter piston 42 receives the discharge pressure guided to the pressure chamber 43 and urges the swash plate 8 in the direction in which the tilt angle increases. The stepped surface 42c formed on the outer periphery of the small diameter piston 42 is the pressure receiving surface of the small diameter piston 42 that receives the discharge pressure guided to the pressure chamber 43.

Further, in the small diameter piston 42, a spring accommodating hole 44a for accommodating one end of the outer spring 51a and the inner spring 51b, which will be described later, is formed at the end opposite to the swash plate 8. Further, the small-diameter piston 42 is formed with a communication hole 44b for communicating the spring accommodating hole 44a and the inside of the case 3. Therefore, the inside of the spring accommodating hole 44a and the second piston accommodating hole 41 communicates with the tank through the inside of the communication hole 44b and the case 3.

The large-diameter piston 32 is formed to have a larger control pressure receiving area than the small-diameter piston 42. As shown in FIG. 1, the large-diameter piston 32 is provided on the side opposite to the small-diameter piston 42 with respect to the swash plate 8. That is, the large-diameter piston 32 is arranged so that the position in the circumferential direction of the shaft 1 with respect to the central axis substantially coincides with the small-diameter piston 42.

The regulator 50 adjusts the control pressure guided to the control pressure chamber 33 according to the discharge pressure of the piston pump 100, and controls the horsepower (output) of the piston pump 100.

The regulator 50 moves according to the urging force of the outer spring 51a and the inner spring 51b and the outer spring 51a and the inner spring 51b as urging members for urging the small diameter piston 42 toward the swash plate 8, and controls the pressure. It has a control spool 52 for adjusting the pressure, and a pressing mechanism 60 for pressing the control spool 52 against the urging force of the outer spring 51a and the inner spring 51b.

The outer spring 51a and the inner spring 51b are coil springs, respectively, and expand and contract so as to follow the tilt of the swash plate 8. The inner spring 51b has a smaller winding diameter than the outer spring 51a and is provided inside the outer spring 51a. One end of the outer spring 51a and the inner spring 51b is accommodated in the spring accommodating hole 44a of the small diameter piston 42, and is seated at the bottom of the spring accommodating hole 44a via the spring seat 72. The other ends of the outer spring 51a and the inner spring 51b are seated on the end face of the control spool 52 via the spring seat 73. One spring seat 72 moves with the small diameter piston 42, and the other spring seat 73 moves with the control spool 52.

In the state where the tilt angle of the swash plate 8 is maximized (the state shown in FIG. 1), the other spring seat 73 does not come into contact with the bottom of the second accommodating portion 41b of the second piston accommodating hole 41, and the second spring seat 73 does not come into contact with the bottom. It floats away from the bottom of the accommodating portion 41b.

The natural length (free length) of the outer spring 51a is longer than the natural length of the inner spring 51b. In the state where the tilt angle of the swash plate 8 is maximized (the state shown in FIG. 1), the outer spring 51a is in a state of being compressed by the spring seat 73, while the inner spring 51b has a spring seat (one end thereof). In FIG. 1, it is in a state of floating away from the spring seat 72) (a state of becoming a natural length). That is, when the tilt angle of the swash plate 8 is reduced from the maximum state, only the outer spring 51a is initially compressed, and the length of the outer spring 51a is compressed beyond the natural length of the inner spring 51b. , Both the outer spring 51a and the inner spring 51b are compressed. As a result, the elastic force from the outer spring 51a and the inner spring 51b applied to the swash plate 8 via the small-diameter piston 42 is configured to increase stepwise.

The case body 3a is formed with a spool accommodating hole 50a into which the control spool 52 is slidably inserted. The spool accommodating hole 50a is formed coaxially with the second piston accommodating hole 41 accommodating the small-diameter piston 42, and is provided so as to communicate with the second piston accommodating hole 41 (more specifically, the second accommodating portion 41b).

Further, the case body 3a is formed with a discharge pressure passage 10 through which the discharge pressure of the piston pump 100 is guided, and a control pressure passage 11 for guiding the control pressure to the control pressure chamber 33 of the large-diameter piston 32. The discharge pressure of the piston pump 100 is constantly guided to the discharge pressure passage 10. The control pressure passage 11 communicates with the control pressure chamber 33 through a cover-side passage (not shown) formed in the cover 3b.

The spool accommodating hole 50a opens at the end surface of the case body 3a. The opening of the spool accommodating hole 50a with respect to the end surface of the case body 3a is closed by the cap 90.

As shown in FIG. 2, the control spool 52 has a main body portion 53 that is in sliding contact with the inner peripheral surface of the spool accommodating hole 50a, and a protruding portion 54 that is inserted into the spring seat 73.

The protruding portion 54 is formed to have an outer diameter smaller than that of the main body portion 53, and the stepped surface 55 generated by the difference in outer diameter between the main body portion 53 and the protruding portion 54 abuts on the spring seat 73.

A first control port 56a and a second control port 56b are formed as annular grooves on the outer periphery of the control spool 52, respectively. Further, in the control spool 52, a first control passage 57 communicating with the first control port 56a is formed so as to penetrate the control spool 52 in the radial direction. Further, the control spool 52 is formed with an axial passage 58 provided along the axial direction from one end portion (protruding portion 54). The axial passage 58 communicates the first control passage 57 with the connection passage 73a formed in the spring seat 73 and communicating with the spring accommodating hole 44a (second piston accommodating hole 41).

In this way, the first control passage 57 communicates with the inside of the case 3 through the axial passage 58, the connection passage 73a of the spring seat 73, the spring accommodating hole 44a of the small diameter piston 42, and the communication hole 44b (see FIG. 1). Therefore, the pressure in the first control passage 57 becomes the tank pressure.

The pressing mechanism 60 includes an auxiliary spring 70 as an auxiliary urging member that exerts an urging force on the control spool 52 so as to resist the urging force exerted on the control spool 52 by the outer spring 51a and the inner spring 51b. It has an adjusting mechanism 80 for adjusting the urging force exerted by the auxiliary spring 70, and a pressing piston 61 as a pressing member accommodated in the accommodating hole 91 formed in the cap 90 and in contact with the entire end surface 53a of the control spool 52. ..

The auxiliary spring 70 is a coil spring. The auxiliary spring 70 is housed in a recess 95 formed in the cap 90. One end of the auxiliary spring 70 is seated on the seating member 75 housed in the recess 95 of the cap 90, and the other end is seated on the end face of the pressing piston 61. The auxiliary spring 70 is provided in a compressed state between the seating member 75 and the pressing piston 61, and exerts an urging force on the control spool 52 via the pressing piston 61.

The seating member 75 includes a plate-shaped base portion 76 that is in sliding contact with the inner peripheral surface of the recess 95 of the cap 90, a support portion 77 that projects axially from the base portion 76 and supports the inner circumference of the auxiliary spring 70, and a support portion 77. It has two shaft portions 78a and 78b protruding in the axial direction from the tip of the shaft. One end of the auxiliary spring 70 is seated on a stepped surface (end surface of the base portion 76 on the support portion 77 side) 76a formed by the difference in outer diameter between the base portion 76 and the support portion 77.

The adjusting mechanism 80 includes a female screw hole 81 formed in the cap 90, a screw member 82 that is screwed into the female screw hole 81 and advances and retracts the seating member 75 along the urging direction of the auxiliary spring 70, and a screw member for the female screw hole 81. It has a nut 83 for fixing the screwing position of 82.

The female screw hole 81 is formed through the bottom of the recess 95 and opens into the recess 95.

The screw member 82 abuts on the base portion 76 from the side opposite to the end surface 76a on which the auxiliary spring 70 is seated in the axial direction. By adjusting the screwing position with the female screw hole 81, the screw member 82 advances and retreats with respect to the seating member 75 along its axial direction (direction of the urging force of the auxiliary spring 70). That is, by advancing and retreating the screw member 82, the seating member 75 advances and retreats so that the auxiliary spring 70 expands and contracts, and the set load (initial load) of the auxiliary spring 70 can be adjusted. As a result, the urging force exerted by the auxiliary spring 70 can be adjusted. By screwing the nut 83 into the screw member 82 and tightening the cap 90, the screwing position of the screw member 82 with respect to the female screw hole 81 is fixed.

The cap 90 accommodating the pressing piston 61 corresponds to a housing member. The accommodating hole 91 of the cap 90 is provided so as to be coaxial with the spool accommodating hole 50a formed in the case body 3a. Further, the accommodating hole 91 of the cap 90 is continuously formed in the recess 95 and coaxially with the recess 95, and faces the spool accommodating hole 50a. One end of the control spool 52 is also accommodated in the accommodating hole 91 of the cap 90.

The accommodating hole 91 of the cap 90 has a first hole portion 92 having a circular cross section and a second hole portion 93 having a larger inner diameter than the first hole portion 92 and formed coaxially with the first hole portion 92. The first hole 92 is formed larger than the inner diameter of the recess 95 and is continuous with the recess 95. The second hole 93 faces the spool accommodating hole 50a of the case body 3a.

The first stepped surface 92a is formed by the difference in inner diameter between the first hole portion 92 and the recess 95. The second stepped surface 93a is formed by the difference in inner diameter between the first hole portion 92 and the second hole portion 93.

The pressing piston 61 has a larger outer diameter than the columnar first piston portion 62 inserted into the first hole portion 92 of the accommodating hole 91 of the cap 90 and the first piston portion 62 inserted into the second hole portion 93. It has a second piston portion 63.

The first piston portion 62 is in sliding contact with the inner peripheral surface of the first hole portion 92 of the accommodating hole 91. As a result, the pressing piston 61 is guided to move along the axial direction of the accommodating hole 91 while the movement of the accommodating hole 91 in the radial direction (direction perpendicular to the axial direction) is restricted by the first hole portion 92. To. In this way, the first hole portion 92 corresponds to the guide portion.

The second piston portion 63 is formed in a columnar shape having an outer diameter larger than the outer diameter of the control spool 52. The end surface 63a of the second piston portion 63 (the end surface of the pressing piston 61 facing the control spool 52) is formed as a circular flat surface. Further, the end surface 53a of the control spool 52 facing the end surface 63a of the second piston portion 63 is also formed as a circular flat surface. As a result, the end surface 53a of the control spool 52 comes into contact (surface contact) with the end surface 63a of the second piston portion 63 of the pressing piston 61 as a whole. In this embodiment, the first piston portion 62 is also formed to have an outer diameter larger than the outer diameter of the control spool 52.

The pressing piston 61 is pressed so that the first piston portion 62 abuts on the first stepped surface 92a of the accommodating hole 91 by the urging force of the outer spring 51a transmitted via the control spool 52. As a result, the movement of the control spool 52 to the left in the figure due to the urging force of the outer spring 51a is restricted by the pressing piston 61.

Further, the pressing piston 61 is formed with a pair of shaft portion insertion holes 61a, 61b into which a pair of shaft portions 78a, 78b of the seating member 75 are inserted, respectively. By inserting the pair of shaft portions 78a and 78b into the pair of shaft portion insertion holes 61a and 61b of the pressing piston 61, respectively, the pair of shaft portions 78a and 78b and the shaft portions 78a and 78b are provided in the pressing piston 61. The inner walls of the shaft insertion holes 61a and 61b to be inserted form a pair of signal pressure chambers 60a and 60b to which the signal pressure used for horsepower control is guided.

One signal pressure chamber 60a is formed in a first communication port 64a formed on the outer periphery of the pressing piston 61, a first connection passage 65a connecting the signal pressure chamber 60a and the first communication port 64a, and a cap 90. It communicates with the discharge pressure passage 10 through the first cap passage 90a. Therefore, the discharge pressure (self-pressure) of the piston pump 100 is guided to the signal pressure chamber 60a as the signal pressure. The other signal pressure chamber 60b is formed in a second communication port 64b formed on the outer periphery of the pressing piston 61, a second connection passage 65b connecting the signal pressure chamber 60b and the second communication port 64b, and a cap 90. The second cap passage 90b communicates with an external pressure passage (not shown) formed in the case body 3a. An external pump pressure as a signal pressure discharged from another hydraulic pump driven by a power source together with the piston pump 100 is guided to the external pressure passage, for example. In this way, the signal pressure chambers 60a and 60b are pressure chambers that are independent of each other, and different signal pressures are derived from each other.

The pressing piston 61 is inserted into the accommodating hole 91 in a state where the first communication port 64a and the first cap passage 90a communicate with each other and the second communication port 64b and the second cap passage 90b communicate with each other. In this state, rotation is restricted by a detent mechanism (not shown). The detent mechanism is known as long as it allows the pressing piston 61 to move in the accommodation hole 91 in the axial direction and regulates the rotation of the pressing piston 61 in the accommodation hole 91. Since the configuration can be adopted, a detailed description will be omitted. For example, the shaft portions 78a and 78b are formed separately from the support portion 77 (seating member 75), and holes are formed in the support portion 77 into which the shaft portions 78a and 78b are inserted to form the shaft portions 78a and 78b. May be used as a detent mechanism.

The signal pressure guided to the signal pressure chambers 60a and 60b acts on the inner wall portion of the signal pressure chambers 60a and 60b facing the shaft portions 78a and 78b. Therefore, the control spool 52 receives the signal pressure via the pressing piston 61 by the pressure receiving area corresponding to the cross-sectional area of the shaft portions 78a and 78b (in other words, the cross-sectional area of the shaft portion insertion holes 61a and 61b), and by the signal pressure. The outer spring 51a and the inner spring 51b are urged in the direction of compression. In this way, the pressing piston 61 receives the thrust due to the resultant force of the signal pressures guided to the signal pressure chambers 60a and 60b, and presses the control spool 52 so as to resist the urging force of the outer spring 51a and the inner spring 51b. ..

As described above, the control spool 52 is urged in the direction away from the swash plate 8 (left direction in the figure) by the urging force of the outer spring 51a and the inner spring 51b. The control spool 52 approaches the swash plate 8 by the discharge pressure and the external pump pressure of the piston pump 100 guided to the signal pressure chambers 60a and 60b via the pressing piston 61 and the urging force by the auxiliary spring 70. Be urged. That is, the control spool 52 moves so that the urging force of the outer spring 51a and the inner spring 51b, the urging force of the auxiliary spring 70, the discharge pressure of the piston pump 100, and the urging force of the external pump pressure are balanced. In this way, the horsepower control characteristics of the regulator 50 can be adjusted by applying the urging force of the auxiliary spring 70 and the thrust of the signal pressure chambers 60a and 60b to the control spool 52.

At this time, the pressing piston 61 receives thrust due to the resultant force of the signal pressures of the signal pressure chambers 60a and 60b, and abuts on the entire end surface 53a of the control spool 52 to press the control spool 52. Therefore, the control spool 52 can be urged along the axial direction (in other words, parallel to the central axis) without being tilted with respect to the central axis of the control spool 52 (spool accommodating hole 50a). The occurrence of wear between the control spool 52 and the spool accommodating hole 50a is suppressed.

To specifically explain the movement of the control spool 52, the control spool 52 moves between two positions, a first position and a second position. 1 and 2 (the same applies to FIGS. 3 and 4 described later) show a state in which the control spool 52 is in the second position. The control spool 52 switches from the second position shown in FIGS. 1 and 2 to the first position as it moves to the right in the figure.

The first position is a position in which the tilt angle of the swash plate 8 is reduced to reduce the discharge capacity of the piston pump 100. In the first position, the discharge pressure passage 10 and the control pressure passage 11 of the case body 3a communicate with each other through the second control port 56b of the control spool 52, and the first control passage 57 and the control pressure passage 11 of the control spool 52 are communicated with each other. Communication is cut off. Therefore, in the first position, the discharge pressure of the piston pump 100 is guided to the control pressure chamber 33 of the first urging mechanism 30.

The second position is a position in which the tilt angle of the swash plate 8 is increased to increase the discharge capacity of the piston pump 100. In the second position, the control pressure passage 11 and the first control passage 57 of the control spool 52 communicate with each other through the first control port 56a, and the communication between the discharge pressure passage 10 and the control pressure passage 11 is cut off. Therefore, in the second position, the tank pressure is guided to the control pressure chamber 33.

Next, the operation of the piston pump 100 will be described.

In the piston pump 100, the regulator 50 controls the horsepower to control the discharge capacity (tilt angle of the swash plate 8) of the piston pump 100 so that the discharge pressure of the piston pump 100 is kept constant.

The control spool 52 of the regulator 50 is urged to be in the first position by the urging force of the signal pressure chambers 60a and 60b (the discharge pressure of the piston pump 100 and the external pump pressure) and the urging force of the auxiliary spring 70. At the same time, it is urged to be in the second position by the urging force of the outer spring 51a and the inner spring 51b.

When the signal pressure of the signal pressure chambers 60a and 60b and the urging force of the auxiliary spring 70 are kept below the urging force of the outer spring 51a, the control spool 52 of the regulator 50 is located in the second position and the swash plate 8 is tilted. The turning angle is kept to the maximum (see FIG. 1).

The discharge pressure of the piston pump 100 increases as the load of the hydraulic cylinder driven by the discharge pressure of the piston pump 100 increases. When the discharge pressure of the piston pump 100 rises from the state where the tilt angle of the swash plate 8 is kept to the maximum, the resultant force of the signal pressures of the signal pressure chambers 60a and 60b and the urging force by the auxiliary spring 70 is attached to the outer spring 51a. It will surpass the power. As a result, the control spool 52 moves in the direction of switching from the second position to the first position (right direction in the figure). When the control spool 52 moves to the first position, the discharge pressure is guided from the discharge pressure passage 10 to the control pressure passage 11, so that the control pressure rises. More specifically, as the control spool 52 moves to the first position, the opening area (flow path area) of the second control port 56b of the control spool 52 with respect to the control pressure passage 11 increases. Therefore, as the amount of movement of the control spool 52 in the direction of switching to the first position (right direction in the figure) increases, the control pressure guided to the control pressure passage 11 increases. As the control pressure guided to the control pressure passage 11 increases, the large-diameter piston 32 (see FIG. 1) moves toward the swash plate 8, and the swash plate 8 tilts in a direction in which the tilt angle becomes smaller. Therefore, the discharge capacity of the piston pump 100 is reduced.

When the swash plate 8 is tilted in a direction in which the tilt angle becomes smaller, the small-diameter piston 42 follows the swash plate 8 and moves to the left in the figure so as to compress the outer spring 51a and the inner spring 51b. In other words, when the swash plate 8 tilts in the direction in which the tilt angle becomes smaller, the small diameter piston 42 urges the control spool 52 through the outer spring 51a (and the inner spring 51b) in the direction of switching to the second position. Move to. As a result, when the control spool 52 is pushed back and moves in the direction of switching to the second position, the control pressure supplied to the control pressure chamber 33 through the control pressure passage 11 decreases. When the urging force applied to the swash plate 8 by the control pressure is balanced with the urging force applied to the swash plate 8 from the outer spring 51a (and the inner spring 51b) as the control pressure decreases, the large-diameter piston 32 moves. (Tilt of the swash plate 8) stops. As described above, when the discharge pressure of the piston pump 100 increases, the discharge capacity decreases.

On the contrary, the discharge pressure of the piston pump 100 decreases as the load of the hydraulic cylinder driven by the discharge pressure of the piston pump 100 decreases. When the discharge pressure of the piston pump 100 decreases, the resultant force of the signal pressures of the signal pressure chambers 60a and 60b and the urging force by the auxiliary spring 70 becomes lower than the urging force by the outer spring 51a and the inner spring 51b. As a result, the control spool 52 moves in the direction of switching from the first position to the second position. When the control spool 52 moves to the second position, the control pressure passage 11 communicates with the first control passage 57, which is the tank pressure, so that the control pressure drops. As the control pressure decreases, the swash plate 8 tilts in the direction in which the tilt angle increases due to the small-diameter piston 42 that receives the urging force of the outer spring 51a and the inner spring 51b.

When the swash plate 8 tilts in a direction in which the tilt angle increases, the small-diameter piston 42 that receives the urging force of the outer spring 51a and the inner spring 51b is attached to the swash plate 8 so that the outer spring 51a and the inner spring 51b extend. It follows and moves to the right in the figure. As a result, the urging force received by the control spool 52 from the outer spring 51a and the inner spring 51b becomes smaller. Therefore, the control spool 52 receives the signal pressures of the signal pressure chambers 60a and 60b and moves in the direction of compressing the outer spring 51a and the inner spring 51b. That is, the control spool 52 moves in the direction of switching from the second position to the first position so as to follow the small diameter piston 42. The control spool 52 is positioned in the first position again, the control pressure rises, and the urging force applied to the swash plate 8 by the control pressure is applied to the swash plate 8 from the outer spring 51a (and the inner spring 51b). When balanced with the force, the movement of the large-diameter piston 32 (tilting of the swash plate 8) stops. As described above, when the discharge pressure of the piston pump 100 decreases, the discharge capacity increases.

As described above, horsepower control is performed so that the discharge capacity of the piston pump 100 decreases as the discharge pressure of the piston pump 100 increases, and the discharge capacity increases as the discharge pressure decreases.

According to the above embodiment, the following effects are obtained.

In the piston pump 100, the pressing mechanism 60 presses the control spool 52 against the urging force of the outer spring 51a and the inner spring 51b by the pressing piston 61 that abuts on the entire end surface 53a of the control spool 52. Therefore, the thrust of the signal pressure and the urging force of the auxiliary spring 70 can be applied to the control spool 52 along the central axis of the control spool 52. Therefore, according to the piston pump 100, the occurrence of wear between the control spool 52 of the regulator 50 and the spool accommodating hole 50a is suppressed. As a result, it is possible to prevent the control pressure adjusted by the regulator 50 from fluctuating due to wear of the control spool 52 and the spool accommodating hole 50a.

Here, in order to apply the thrust due to the signal pressure to the control spool, it is conceivable to form a signal pressure chamber on the control spool. However, when a signal pressure chamber is formed on the control spool, the control spool itself must be changed in order to change the number of signal pressure chambers, which leads to an increase in cost. Further, the number of signal pressure chambers to be formed is limited by the outer diameter of the control spool, so that it cannot be said that the degree of freedom in design is high.

On the other hand, in the present embodiment, the signal pressure chambers 60a and 60b are formed in the pressing mechanism 60, specifically, the pressing piston 61 having a larger outer diameter than the control spool 52. Therefore, according to the present embodiment, it is easy to increase the number of signal pressure chambers 60a and 60b as compared with the case where the signal pressure chambers 60a and 60b are formed in the control spool 52, and the degree of freedom in design is high. .. Further, even if the number and configuration of the signal pressure chambers 60a and 60b are different, the control spool 52 can be shared, so that the manufacturing cost can be reduced.

Further, in the pressing mechanism 60, the thrust due to the signal pressure guided to the signal pressure chambers 60a and 60b acts on the pressing piston 61 and acts on the control spool 52 via the pressing piston 61. That is, the resultant force of the signal pressures guided to the signal pressure chambers 60a and 60b acts on the pressing piston 61 as a thrust. In this way, the thrusts of different signal pressures act on the control spool 52 via the common pressing piston 61, so that even if the magnitude of the signal pressure is different, the force is evenly applied to the end faces of the control spools. It becomes easier to act. Therefore, an urging force can be applied to the control spool 52 from the pressing mechanism 60 along the central axis of the control spool 52.

Further, the outer diameter of the second piston portion 63 of the pressing piston 61 that abuts on the control spool 52 is formed to be larger than the outer diameter of the control spool 52. As a result, the entire end surface 53a of the control spool 52 can be brought into contact with the end surface 63a of the second piston portion 63 of the pressing piston 61, and the pressing mechanism 60 can be more reliably aligned with the central axis of the control spool 52. An urging force can be applied to the control spool 52.

Further, the pressing piston 61 is restricted from moving in the radial direction of the control spool 52 (spool accommodating hole 50a) by the first hole portion 92 of the accommodating hole 91 of the cap 90, and is along the axial direction of the control spool 52. The movement will be guided. As a result, the urging force acting on the control spool 52 from the pressing piston 61 can be more reliably applied along the central axis of the control spool 52. Therefore, the sliding friction generated in the control spool 52 can be reduced, and the wear of the control spool 52 can be suppressed more reliably. Further, by reducing the sliding friction of the control spool 52, the hysteresis of the regulator 50 can be improved.

Further, in the present embodiment, the signal pressure chambers 60a and 60b are formed by inserting the shaft portions 78a and 78b into the shaft portion insertion holes 61a and 61b formed in the pressing piston 61. As a result, the inclination of the pressing piston 61 in the accommodating hole 91 of the cap 90 is also suppressed by the shaft portions 78a and 78b and the shaft portion insertion holes 61a and 61b. Therefore, the urging force acting on the control spool 52 from the pressing piston 61 can be more reliably applied along the central axis of the control spool 52, and the wear generated on the control spool 52 can be more reliably suppressed. ..

Next, a modification of the present embodiment will be described with reference to FIGS. 3 to 5. The following modifications are also within the scope of the present invention, and it is possible to combine the configurations shown in the modifications with the configurations described in the above-described embodiment, or to combine the configurations described in the following different modifications. Is. In the modified examples shown in FIGS. 3 to 5, the same reference numerals are given to the same configurations as those in the above embodiment, and the description thereof will be omitted as appropriate.

(1) First Modification Example First, the first modification shown in FIG. 3 will be described.

In the above embodiment, the signal pressure chambers 60a and 60b are formed in the pressing piston 61, the pressing piston 61 abuts on the control spool 52, and a thrust due to the signal pressure acts on the control spool 52.

On the other hand, in the first modification, the member in which the signal pressure chambers 60a and 60b are formed and the member in contact with the control spool 52 are different members. In other words, the signal pressure chambers 60a and 60b are formed by a member different from the pressing piston 61 (pressing member) that abuts on the control spool 52.

As shown in FIG. 3, the pressing mechanism 60 includes a pressing piston 162 as a pressing member that abuts on the end surface 53a of the control spool 52, and an intermediate piston 163 as an intermediate member in which two shaft insertion holes 161a and 161b are formed. And the signal pin 175a as two shafts that abut on the end face of the pressing piston 162 on the opposite side of the end face 162a that abuts on the control spool 52 and are movably inserted into the two shaft insertion holes 161a and 161b, respectively. It has 175b and.

The pressing piston 162 is a disk-shaped member having an outer diameter larger than the outer diameter of the control spool 52. Similar to the above embodiment, the entire surface of the end surface 53a of the control spool 52 comes into contact with the end surface 162a of the pressing piston 162. The pressing piston 162 is slidably inserted into the second hole portion 93 of the accommodating hole 91. In this first modification, the second hole portion 93 corresponds to a guide portion that regulates the movement of the pressing piston 162 in the radial direction and guides the movement in the axial direction.

The intermediate piston 163 is formed with the first and second communication ports 64a and 64b and the first and second connection passages 65a and 65b similar to those in the above embodiment, and is detented by a detent mechanism (not shown). By movably inserting the signal pins 175a and 175b into the shaft insertion holes 161a and 161b, the signal pressure chamber 60a is inserted into the intermediate piston 163 by the inner walls of the shaft insertion holes 161a and 161b and the signal pins 175a and 175b. , 60b are formed. Although the signal pins 175a and 175b are formed separately from the pressing piston 162, they may be integrally formed with the pressing piston 162. According to this, the rotation of the pressing piston 162 can be stopped by the signal pins 175a and 175b.

By guiding the signal pressure to the signal pressure chambers 60a and 60b, the thrust due to the signal pressure is transmitted to the pressing piston 162 via the signal pins 175a and 175b, and acts on the control spool 52 from the pressing piston 162. As described above, in the first modification, the thrust due to the plurality of signal pressures acts on the control spool 52 through the common pressing piston 162, as in the above embodiment. Further, the pressing piston 162 that abuts on the entire end surface 53a of the control spool 52 receives the thrust generated by the signal pressure of the signal pressure chambers 60a and 60b and resists the urging force of the outer spring 51a and the inner spring 51b. Press. Therefore, even in the first modification, the same action and effect as those in the above embodiment can be obtained.

(2) Second Modified Example Next, a second modified example will be described with reference to FIG.

In the above embodiment, the control spool 52 is accommodated in the spool accommodating hole 50a formed in the case body 3a. Further, the pressing mechanism 60 has an auxiliary spring 70 and an adjusting mechanism 80.

On the other hand, as in the second modification shown in FIG. 4, the sleeve 260 is attached to the mounting hole 3e formed in the case body 3a, and the control spool 52 is accommodated in the spool accommodating hole 250a formed in the sleeve 260. May be good. Further, as shown in FIG. 4, the pressing mechanism 60 does not have to have the auxiliary spring 70 and the adjusting mechanism 80. Hereinafter, a specific description will be given.

In the second modification, the regulator 250 has a sleeve 260 that is attached to the attachment hole 3e formed in the case body 3a.

The sleeve 260 is attached to the case body 3a by screwing it into the female screw 203 formed in the mounting hole 3e of the case body 3a. The sleeve 260 is formed with a spool accommodating hole 250a into which the control spool 52 is inserted and an accommodating hole 291 formed coaxially with the spool accommodating hole 250a and into which the pressing piston 61 is inserted. That is, in the second modification, the sleeve 260 corresponds to the housing member.

Further, the sleeve 260 has a first communication hole 261a that communicates with the control pressure passage 11 through the first port 260a formed on the outer periphery and a second communication hole 261a that communicates with the discharge pressure passage 10 through the second port 260b formed on the outer periphery. The communication hole 261b and the like are formed. The first port 260a and the second port 260b are annular grooves formed on the outer peripheral surface of the sleeve 260, respectively. The first communication hole 261a and the second communication hole 261b intersect with the spool accommodating hole 250a and communicate with the spool accommodating hole 250a, respectively.

One end of the spool accommodating hole 250a formed in the sleeve 260 opens into the second piston accommodating hole 41 accommodating the small-diameter piston 42, as in the above embodiment. The end of the accommodation hole 291 is sealed by a plug 270 that is screwed and attached to the sleeve 260.

The plug 270 has shaft portions 278a and 278b that are inserted into the shaft portion insertion holes 61a and 61b formed in the pressing piston 61. The signal pressure chambers 60a and 60b are formed by the shaft portions 278a and 278b of the plug 270 and the inner walls of the shaft portion insertion holes 61a and 61b of the pressing piston 61.

Further, in the second modification, the pressing piston 61 slides with respect to the accommodating hole 291. Therefore, the accommodating hole 291 functions as a guide portion that restricts the movement of the pressing piston 61 in the radial direction of the control spool 52 and guides the movement in the axial direction.

Even in such a second modification, the thrust due to the plurality of signal pressures acts on the control spool 52 through the common pressing piston 61, as in the above embodiment. Therefore, even in the second modification, the same effect as that of the above embodiment can be obtained.

(3) Third Modified Example Next, a third modified example will be described with reference to FIG.

In the above embodiment, the signal pressure chambers 60a and 60b are formed by the shaft portion insertion holes 61a and 61b formed in the pressing piston 61 and the shaft portions 78a and 78b of the seating member 75. Further, the entire end surface 53a of the control spool 52 comes into contact with the end surface 63a of the pressing piston 61.

On the other hand, in the third modification shown in FIG. 5, the pressing piston 61 is provided with the third piston portion 64 at the end of the first piston portion 62 on the opposite side of the second piston portion 63. The outer diameter of the third piston portion 64 is smaller than the outer diameter of the first piston portion 62, and the first piston step surface 62b is formed between the third piston portion 64 and the first piston portion 62 due to the difference in outer diameter. To. Further, a second piston step surface 63b is formed between the first piston portion 62 and the second piston portion 63 due to the difference in outer diameter. Further, in the accommodating hole 91, a third hole portion 94 into which the third piston portion 64 of the pressing piston 61 is slidably inserted is further formed corresponding to the pressing piston 61 of the third modification. In the third modification, the first stepped surface 92a of the accommodating hole 91 is formed by the difference in inner diameter between the third hole portion 94 and the first hole portion 92. The third hole portion 94 is connected to the recess 95.

In such a third modification, one signal pressure chamber 60a is formed by the outer peripheral surface of the third piston portion 64 of the pressing piston 61, the first piston stepped surface 62b, and the first stepped surface 92a of the accommodating hole 91. .. Further, the outer peripheral surface of the first piston portion 62, the second stepped surface 63b of the second piston, and the second stepped surface 93a of the accommodating hole 91 form the other signal pressure chamber 60b. Further, the pressing piston 61 is formed in a hollow shape having a through hole 61d, and the auxiliary spring 70 is in direct contact with the end surface 53a of the control spool 52 through the through hole 61d of the pressing piston 61. Further, even if the pressing piston 61 moves toward the control spool 52 in the right direction in FIG. 5, the state in which the third piston portion 64 is inserted into the third hole portion 94 of the accommodating hole 91 is maintained. As a result, even if the pressing piston 61 makes a full stroke toward the control spool 52, one signal pressure chamber 60a does not communicate with the other portion of the accommodating hole 91, and the state in which the signal pressure chamber 60a is closed is maintained. Will be done.

A flange portion 353 having a larger outer diameter than the main body portion 53 is provided at the end portion of the control spool 52. Since the pressing piston 61 is provided with a through hole 61d, the flange portion 353 and the pressing piston 61 are in contact with each other by the annular contact surface. As described above, the entire end surface 53a of the control spool 52 may not be in contact with the pressing piston 61, but a part thereof may be in contact with the pressing piston 61. In this case, the contact surface between the control spool 52 and the pressing piston 61 is provided so as to be point-symmetrical about the center point of the control spool 52 in the axial view of the control spool 52, for example, like an annular shape. It is desirable to be. By providing the contact surface in this way, the end surface 63a of the pressing piston 61 evenly contacts the end surface 53a of the control spool 52, so that thrust is applied to the control spool 52 from the pressing piston 61 so that its central axis is inclined. It can be prevented from acting.

Even in such a third modification, the thrust due to the resultant force of the plurality of signal pressures acts on the control spool 52 through the common pressing piston 61. Therefore, even in the third modification, the same action and effect as those of the above embodiment can be obtained.

(4) Other Modification Examples Next, other modification examples will be described.

In the above embodiment, the pair of shaft portion insertion holes 61a and 61b and the pair of shaft portions 78a and 78b form two signal pressure chambers 60a and 60b in the pressing piston 61. On the other hand, the pressing mechanism 60 may have three or more signal pressure chambers, or may have one signal pressure chamber. Further, the type of signal pressure is not limited to the above embodiment, and can be arbitrarily configured according to the application of the piston pump 100 and the like. For example, when the piston pump 100 is a so-called split flow type in which hydraulic oil is discharged from two ports, the discharge pressure of the hydraulic oil discharged from one port is used as a signal pressure to guide the hydraulic oil to one signal pressure chamber. , The discharge pressure of the hydraulic oil discharged from the other port may be used as a signal pressure to be guided to the other signal pressure chamber.

Further, in the above embodiment, a signal pressure larger than the tank pressure is guided to each of the two signal pressure chambers 60a and 60b, and is generated by the signal pressure guided to the two signal pressure chambers 60a and 60b to the pressing piston 61. Thrust acts on each. That is, the resultant force of the thrust generated by the signal pressures guided to the two signal pressure chambers 60a and 60b acts on the pressing piston 61. On the other hand, a tank pressure may be guided as a signal pressure to a part of the plurality of signal pressure chambers. In this case, in the signal pressure chamber to which the tank pressure is guided, the thrust for urging the pressing piston 61 is not exerted, in other words, the magnitude of the thrust exerted is "0". In the present specification, the resultant force of signal pressures guided to a plurality of signal pressure chambers means to include the resultant force with the thrust having a magnitude of "0". Therefore, in the present invention, a signal pressure larger than the tank pressure is guided to one signal pressure chamber among a plurality of signal pressure chambers to generate a thrust larger than "0", and all the other signal pressure chambers are tanks. A form in which the pressure is guided and the thrust becomes "0" (that is, the magnitude of the resultant force corresponds to the thrust exerted by a single signal pressure chamber in which a signal pressure larger than the tank pressure is guided). Is also included.

Hereinafter, the configurations, actions, and effects of the embodiments of the present invention will be collectively described.

The piston pump 100 slides in a cylinder block 2 that rotates with the rotation of the shaft 1, a plurality of cylinders 2b formed in the cylinder block 2 and arranged at predetermined intervals in the circumferential direction of the shaft 1, and a cylinder 2b. A piston 5 that is freely inserted to partition the volume chamber 6 inside the cylinder 2b, and a tiltable swash plate 8 that reciprocates the piston 5 so as to expand and contract the volume chamber 6 as the cylinder block 2 rotates. The first urging mechanism 30 that urges the swash plate 8 according to the supplied control pressure, the second urging mechanism 40 that urges the swash plate 8 so as to oppose the first urging mechanism 30, and the second. 1 A regulator 50 that controls the control pressure guided to the urging mechanism 30 according to the self-pressure of the piston pump 100, and the regulator 50 includes an outer spring 51a and an inner side that expands and contracts according to the tilt of the swash plate 8. The control spool 52 that moves according to the urging force of the spring 51b, the outer spring 51a and the inner spring 51b to adjust the control pressure, and the control spool 52 presses against the urging force of the outer spring 51a and the inner spring 51b. The pressing mechanism 60 is controlled by the resultant force of the signal pressure chambers 60a and 60b to which a plurality of signal pressures are guided and the signal pressures guided to the plurality of signal pressure chambers 60a and 60b. It has pressing pistons 61 and 162 that press the spool 52 against the urging force of the outer spring 51a and the inner spring 51b.

In this configuration, even if signal pressures are guided to a plurality of signal pressure chambers 60a and 60b, the thrust generated by each signal pressure acts on the same pressing pistons 61 and 162, and is controlled by the pressing pistons 61 and 162. 52 is pressed against the urging force of the outer spring 51a and the inner spring 51b. Therefore, even if there is a difference in the magnitude of the signal pressure, the control spool 52 is pressed by the common pressing pistons 61 and 162, so that the thrust of the signal pressure is evenly distributed along the central axis of the control spool 52. It becomes easy to act on the control spool 52. Therefore, the friction generated in the control spool 52 is reduced, and the wear of the control spool 52 can be suppressed.

Further, in the piston pump 100, the outer diameters of the pressing pistons 61 and 162 are formed to be larger than the outer diameter of the control spool 52.

In this configuration, the entire end surface 53a of the control spool 52 is more reliably in contact with the pressing pistons 61 and 162.

Further, in the piston pump 100, the regulator 50 has a housing member (cap 90, sleeve 260) in which accommodating holes 91, 291 for accommodating the pressing pistons 61 and 162 are formed coaxially with the central axis of the control spool 52. The accommodation holes 91 and 291 restrict the movement of the pressing pistons 61 and 162 in the direction perpendicular to the central axis of the control spool 52, and guide the movement of the pressing pistons 61 and 162 along the central axis of the control spool 52. A guide portion (first hole portion 92, second hole portion 93, accommodating hole 291) is provided.

In this configuration, the urging force acting on the control spool 52 from the pressing pistons 61 and 162 can be more reliably applied along the central axis of the control spool 52. Therefore, the wear generated on the control spool 52 can be suppressed more reliably.

Further, in the piston pump 100, the pressing mechanism 60 further has a seating member 75 having shaft portions 78a and 78b protruding in the axial direction of the control spool 52 toward the pressing piston 61, and the pressing piston 61 has a shaft portion. 78a and 78b are inserted to form shaft insertion holes 61a and 61b forming signal pressure chambers 60a and 60b together with the shafts 78a and 78b.

In this configuration, the signal pressure chambers 60a and 60b are formed by inserting the shaft portions 78a and 78b into the shaft portion insertion holes 61a and 61b formed in the pressing piston 61, so that the pressing piston 61 is tilted. Is suppressed by the shaft portions 78a and 78b.

Further, in the first modification, the pressing mechanism 60 is provided along the axial direction of the control spool 52 and has signal pins 175a and 175b that abut on the end surface of the pressing piston 162 on the opposite side to the end surface that abuts on the control spool 52. Further has an intermediate piston 163 into which the signal pins 175a, 175b are inserted and along with the signal pins 175a, 175b, the shaft insertion holes 161a, 161b forming the signal pressure chambers 60a, 60b are formed.

Although the embodiments of the present invention have been described above, the above embodiments are only a part of the application examples of the present invention, and the technical scope of the present invention is limited to the specific configuration of the above embodiments. No.

100 ... Piston pump (hydraulic rotary machine), 1 ... Shaft (drive shaft), 2 ... Cylinder block, 2b ... Cylinder, 3 ... Case, 5 ... Piston, 6 ... Volume chamber, 8 ... Slanted plate, 30 ... First Bounce mechanism, 40 ... 2nd urging mechanism, 50, 250 ... Regulator, 51a ... Outer spring (brute force member), 51b ... Inner spring (brute force member), 52 ... Control spool, 60 ... Pressing mechanism, 60a, 60b ... Signal pressure chamber, 61, 162 ... Pressing piston (pressing member), 61a, 61b, 161a, 161b ... Shaft insertion hole, 75 ... Seating member, 78a, 78b ... Shaft, 90 ... Cap (housing member), 91 ... Accommodating hole, 92 ... First hole portion (guide portion), 93 ... Second hole portion (guide portion), 163 ... Intermediate piston (intermediate member), 175a, 175b ... Signal pin (shaft portion), 260 ... Sleeve (Housing member), 291 ... Accommodation hole (guide part)

Claims (4)

It ’s a hydraulic rotary machine.
A cylinder block that rotates with the drive shaft,
A plurality of cylinders formed in the cylinder block and arranged at predetermined intervals in the circumferential direction of the drive shaft, and
A piston that is slidably inserted into the cylinder and partitions a volume chamber inside the cylinder,
A tiltable swash plate that reciprocates the piston so as to expand or contract the volume chamber.
The first urging mechanism that urges the swash plate according to the supplied control pressure,
A second urging mechanism that urges the swash plate so as to oppose the first urging mechanism,
A regulator that controls the control pressure guided to the first urging mechanism according to the self-pressure of the hydraulic rotary machine is provided.
The regulator is
An urging member that expands and contracts following the tilt of the swash plate,
A control spool that moves according to the urging force of the urging member to adjust the control pressure, and
It has a pressing mechanism that presses the control spool against the urging force of the urging member.
The pressing mechanism is
Multiple signal pressure chambers from which multiple signal pressures are derived, and
A hydraulic rotator characterized by having a pressing member on which a resultant force of the signal pressures guided to the plurality of signal pressure chambers acts to press the control spool against the urging force of the urging member. .. The regulator has a housing member in which an accommodating hole accommodating the pressing member is formed coaxially with the central axis of the control spool.
The accommodating hole is provided with a guide portion that regulates the movement of the pressing member in a direction perpendicular to the central axis of the control spool and guides the movement of the pressing member along the central axis of the control spool. The hydraulic rotary machine according to claim 1. The pressing mechanism further includes a seating member having a shaft portion that protrudes in the axial direction of the control spool toward the pressing member.
The hydraulic rotary machine according to claim 1 or 2, wherein the shaft portion is inserted into the pressing member to form a shaft portion insertion hole forming the signal pressure chamber together with the shaft portion. The pressing mechanism is
A shaft portion provided along the axial direction of the control spool and abutting on the end face of the pressing member on the side opposite to the end face abutting on the control spool.
The hydraulic rotator according to claim 1 or 2, further comprising an intermediate member into which the shaft portion is inserted and together with the shaft portion is formed with a shaft portion insertion hole forming the signal pressure chamber. ..

Images