WO2023085258A1 - Hydraulic rotary machine - Google Patents

Abstract

A piston pump 100 comprises a first biasing part 20 that biases a swashplate 8 in accordance with a supplied control pressure, a second biasing part 30 that biases the swashplate 8 against the first biasing part 20, and a regulator 50 that controls the control pressure directed to the first biasing part 20 in accordance with the pressure of the piston pump 100, the regulator 50 having: an external spring 51a and an internal spring 51b that extend and contract in conformity with the tilt of the swashplate 8; a control spool 52 that moves in accordance with the biasing force of the external spring 51a and the internal spring 51b and adjusts the control pressure; an auxiliary spring 61 that exerts, on the control spool 52, a biasing force against the biasing force of the external spring 51a and the internal spring 51b; and a housing chamber 65 that houses the auxiliary spring 61, a signal pressure that exerts thrust against the control spool 52 being directed to the housing chamber 65.

Description

hydraulic rotary machine

The present invention relates to a hydraulic rotary machine.

JP2008-240518A discloses a swash plate type piston pump provided with a horsepower control regulator that controls the discharge pressure and the discharge flow rate with constant horsepower characteristics such that the output is substantially constant. This swash plate type piston pump has a tilt actuator that changes the tilt angle of the swash plate. And prepare.

The horsepower control regulator includes a control spring that presses a feedback pin that follows the swash plate and pushes it against the swash plate, and a control spool that controls the hydraulic pressure guided to the pressure chamber of the large-diameter piston. Hydraulic pressure such as discharge pressure and signal pressure acts on the control spool, and the control spool moves so that the force received by the hydraulic pressure and the force received by the control spring are balanced.

In the horsepower control regulator disclosed in JP2008-240518A, the control spool moves so that the forces received by the spring, hydraulic pressure, etc. are balanced, thereby controlling the hydraulic pressure introduced to the pressure chamber of the large-diameter piston. Therefore, the control characteristics of the horsepower control regulator are determined according to the force acting on the control spool.

In order to achieve various control characteristics in such a regulator, it is conceivable to increase the degree of design freedom by providing multiple configurations that exert force on the control spool. However, providing a plurality of configurations for urging the control spool would result in an increase in the size of the hydraulic rotary machine.

An object of the present invention is to provide a hydraulic rotating machine that can improve the degree of freedom of the control characteristics of the regulator while suppressing an increase in size.

According to one aspect of the present invention, a hydraulic rotary machine includes 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 A piston that is slidably inserted to define a volume chamber inside the cylinder, a tiltable swash plate that reciprocates the piston so as to expand and contract the volume chamber, and a swash plate depending on the supplied control pressure are attached. a first biasing portion for biasing; a second biasing portion for biasing the swash plate against the first biasing portion; and a regulator for controlling the control pressure guided to the first biasing portion. , the regulator includes an urging member that expands and contracts following the tilting of the swash plate, a control spool that moves according to the urging force of the urging member to adjust the control pressure, and a control spool that resists the urging force of the urging member. an auxiliary biasing member exerting a biasing force on the control spool, and a storage chamber accommodating the auxiliary biasing member, and the storage chamber is provided so as to resist the biasing force of the biasing member It is characterized in that a signal pressure is directed to exert a thrust on the control spool.

FIG. 1 is a cross-sectional view of a hydraulic rotating machine according to a first embodiment of the present invention. FIG. 2 is a diagram showing the configuration of the regulator of the hydraulic rotating machine according to the first embodiment of the present invention, and is an enlarged cross-sectional view of a portion A in FIG. FIG. 3 is a diagram showing a state in which the control spool moves from the state shown in FIG. 2 and abuts against the case body. FIG. 4 is a cross-sectional view showing a modification of the hydraulic rotating machine according to the first embodiment of the present invention, corresponding to FIG. FIG. 5 is a cross-sectional view showing the configuration of the regulator of the hydraulic rotating machine according to the second embodiment of the present invention. FIG. 6 is a diagram showing the configuration of the regulator of the hydraulic rotary machine according to the second embodiment of the present invention, and is an enlarged cross-sectional view of the portion B in FIG. FIG. 7 is a diagram for explaining the action of the transmission pin in the second embodiment of the present invention, and is an enlarged view of the contact portion between the transmission pin and the second seating portion. FIG. 8 is an enlarged cross-sectional view showing the configuration of the regulator of the hydraulic rotating machine according to the third embodiment of the present invention. FIG. 9 is a cross-sectional view of a hydraulic rotary machine according to a fourth embodiment of the invention.

(First embodiment)
A hydraulic rotating machine 100 according to a first embodiment of the present invention will be described below with reference to the drawings.

The hydraulic rotary machine 100 functions as a piston pump capable of supplying working oil as a working fluid by rotating a shaft (drive shaft) 1 with power from an external drive source and reciprocating a piston 5 . Further, the hydraulic rotary machine 100 functions as a piston motor capable of outputting rotational driving force by causing the piston 5 to reciprocate and the shaft 1 to rotate due to the fluid pressure of hydraulic oil supplied from the outside. The hydraulic rotary machine 100 may function only as a piston pump, or may function only as a piston motor. A drive source that drives the hydraulic rotary machine 100 is, for example, an engine or an electric motor.

In the following description, the case where the hydraulic rotary machine 100 is used as a piston pump will be exemplified, and the hydraulic rotary machine 100 will be referred to as the "piston pump 100".

The piston pump 100 is used, for example, as a hydraulic supply source that supplies hydraulic oil to an actuator (not shown) such as a hydraulic cylinder that drives an object to be driven. The piston pump 100 includes, as shown in FIG. 1 , a shaft 1 rotated by a drive source, a cylinder block 2 connected to the shaft 1 and rotating together with the shaft 1 , and a case 3 housing the cylinder block 2 .

The case 3 includes a cylindrical case main body 3a with a bottom, a cover 3b that seals an open end of the case main body 3a and through which the shaft 1 is inserted, and an auxiliary case portion 3f that accommodates an auxiliary biasing portion 60 described later. Prepare. The inside of the case 3 communicates with a tank (not shown) through a drain passage (not shown). The inside of the case 3 may communicate with a later-described suction passage (not shown).

A power source (not shown) such as an engine is connected to one end 1a of the shaft 1 that protrudes to the outside through the insertion hole 3c of the cover 3b. An end portion 1a of the shaft 1 is rotatably supported in an insertion hole 3c of a cover 3b via a bearing 4a. The other end 1b of the shaft 1 is accommodated in a shaft accommodation hole 3d provided in the bottom of the case body 3a and rotatably supported via a bearing 4b. Although not shown, the other end 1b of the shaft 1 is provided with 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. Coaxially coupled for rotation.

The cylinder block 2 has a through hole 2a through which the shaft 1 passes, and is spline-coupled with the shaft 1 through the through hole 2a. As a result, the cylinder block 2 rotates as the shaft 1 rotates.

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

The piston pump 100 includes a shoe 7 that is rotatably connected to the spherical seat 5a of the piston 5 and is in sliding contact with the spherical seat 5a, a swash plate 8 that is in sliding contact with the shoe 7 as the cylinder block 2 rotates, the cylinder block 2 and a case. and a valve plate 9 provided between the bottom of the main body 3a.

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 slides on 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 comes into sliding contact with the outer surface of the received spherical seat 5a. Thereby, the shoe 7 can be angularly displaced in all directions with respect to the spherical seat 5a.

The swash plate 8 is tiltably supported by the cover 3b in order to make the discharge amount of the piston pump 100 variable. The flat plate portion 7b of the shoe 7 is in 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 main body 3a. Although not shown, the valve plate 9 has a suction port connecting the suction passage formed in the cylinder block 2 and the volume chamber 6, and a discharge passage formed in the cylinder block 2 and the volume chamber 6. A discharge port is formed.

The piston pump 100 has a first biasing portion 20 that tilts the swash plate 8 in a direction in which the tilting angle decreases according to the supplied fluid pressure, and resists the biasing force exerted by the first biasing portion 20. a second biasing portion 30 that biases the swash plate 8 in a direction that increases the tilt angle of the swash plate 8; And further comprising.

As shown in FIG. 1, the first urging portion 20 includes a control piston 22 that is slidably inserted into a piston receiving hole 21 formed in the cover 3b and abuts against the swash plate 8, and the control piston 22 pushes the piston receiving hole. and a control pressure chamber 23 defined within 21 .

A fluid pressure (hereinafter referred to as "control pressure") adjusted by a regulator 50 is introduced into the control pressure chamber 23 . The control piston 22 urges the swash plate 8 in the direction of decreasing the tilt angle by the control pressure introduced to the control pressure chamber 23 .

The second biasing portion 30 is a support spring as a support biasing member. Below, the second biasing portion 30 is also referred to as a “support spring 30”. The support spring 30 is a coil spring, and exerts a biasing force against the biasing force of the first biasing portion 20 to support the swash plate 8 .

As shown in FIG. 2, one end of the support spring 30 is seated on the first spring seat 31, and the other end is seated on the bottom of the case body 3a. The support spring 30 is provided in a compressed state between the first spring seat 31 and the case body 3a. The other end of the support spring 30 is seated on the bottom of the case main body 3a, and an annular support groove 3e for supporting the other end is formed. Therefore, the support spring 30 is configured so as not to exert an urging force on the control spool 52, which will be described later.

The first spring seat 31 is a substantially cylindrical member, and includes a cylindrical sliding portion 32 and a first boss portion 33 having an outer diameter smaller than that of the sliding portion 32 and protruding axially from the sliding portion 32 . a second boss portion 34 having an outer diameter smaller than that of the first boss portion 33 and protruding axially from the first boss portion 33; and a third boss portion 35 that protrudes into.

One end of the support spring 30 is seated on the first spring seat 31 using a stepped surface 32a formed by the difference in outer diameter between the sliding portion 32 and the first boss portion 33 as a seating surface. The first spring seat 31 moves as the swash plate 8 tilts due to the biasing forces of the support spring 30 and an outer spring 51a and an inner spring 51b, which will be described later.

The first spring seat 31 is provided with a contact portion 31a which is formed in a substantially spherical shape and which contacts the swash plate 8 . The sliding portion 32 of the first spring seat 31 is slidably inserted into a guide hole 41 formed in a guide wall portion 40 provided on the inner periphery of the case body 3a. The guide hole 41 is formed in the guide wall portion 40 such that its central axis is parallel to the central axis of the shaft 1 and is parallel or coaxial (coaxial in this embodiment) with the central axis of the control spool 52 described later. be.

The first spring seat 31 is guided along the central axis direction of the guide hole 41 by sliding the sliding portion 32 of the first spring seat 31 with respect to the guide hole 41 . As a result, the biasing force of the support spring 30 (and an outer spring 51 a and an inner spring 51 b to be described later) is applied to the swash plate 8 along the axial direction of the guide hole 41 via the first spring seat 31 . In other words, the first spring seats 31 move so as to follow the tilting of the swash plate 8, and the support springs 30 (and the outer springs 51a and inner springs 51b, which will be described later) expand and contract. Thus, the first spring seat 31 also functions as a feedback pin that transmits the tilting of the swash plate 8 to the regulator 50 .

The first spring seat 31 is formed separately into a portion on which the support spring 30, the outer spring 51a, and the inner spring 51b are seated, and a portion that is guided by the guide hole 41 and comes into contact with the swash plate 8. may be

As shown in FIG. 1, the control piston 22 of the first biasing portion 20 is provided on the opposite side of the first spring seat 31 across the swash plate 8 . That is, the control piston 22 and the first spring seat 31 are arranged such that their circumferential positions with respect to the central axis of the shaft 1 substantially coincide with each other.

The regulator 50 controls the horsepower (output) of the piston pump 100 by adjusting the control pressure guided to the control pressure chamber 23 of the first biasing section 20 according to the load of the drive source that drives the piston pump 100 . More specifically, when the load of the drive source fluctuates, the discharge pressure of piston pump 100 also fluctuates. Therefore, in the present embodiment, the regulator 50 adjusts the control pressure according to the self-pressure of the piston pump 100, thereby executing horsepower control according to the load of the drive source.

The regulator 50 moves according to the biasing force of the outer spring 51a and the inner spring 51b as biasing members that bias the swash plate 8 via the first spring seat 31, and the outer spring 51a and the inner spring 51b. A control spool 52 that adjusts the control pressure, and an auxiliary biasing portion 60 that exerts a biasing force against the control spool 52 so as to resist the biasing force exerted on the control spool 52 by the outer spring 51a and the inner spring 51b. , has

The outer spring 51a and the inner spring 51b are coil springs and expand and contract to follow the tilting of the swash plate 8. The inner spring 51b has a winding diameter smaller than that of the outer spring 51a and is provided inside the outer spring 51a. The outer spring 51 a has a winding diameter smaller than that of the support spring 30 and is provided inside the support spring 30 . That is, both the outer spring 51 a and the inner spring 51 b are provided inside the support spring 30 .

One end of the outer spring 51 a and the inner spring 51 b is seated on the first spring seat 31 . Specifically, as shown in FIG. 2, the outer spring 51a has a stepped surface 33a formed by a difference in outer diameter between the first boss portion 33 and the second boss portion 34 of the first spring seat 31 as a seating surface. The first spring seat 31 is seated. The inner spring 51b can be seated on the first spring seat 31 using a stepped surface 34a formed by a difference in outer diameter between the second boss portion 34 and the third boss portion 35 of the first spring seat 31 as a seating surface. The third boss portion 35 is inserted inside the inner spring 51b and supports the inner circumference of the inner spring 51b.

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 second spring seat 36. The second spring seat 36 moves with the control spool 52 .

The second spring seat 36 has an outer diameter smaller than the inner diameter of the support spring 30 and is provided inside the support spring 30 . As described above, the other end of the support spring 30 is not seated on the second spring seat 36, but is seated on the support groove 3e on the bottom of the case body 3a. Therefore, in the support spring 30 , one end seated on the first spring seat 31 moves to follow the tilting of the swash plate 8 , and the other end seated on the second spring seat 36 moves to follow the tilting of the swash plate 8 . Do not move to follow That is, the other end of the support spring 30 is configured so as not to move due to tilting of the swash plate 8 .

When the tilting angle of the swash plate 8 is maximized (the state shown in FIG. 1), the second spring seat 36 does not come into contact with the bottom of the case body 3a, but floats away from the bottom of the case body 3a. becomes.

The natural length (free length) of the outer spring 51a is longer than the natural length of the inner spring 51b. When the tilt angle of the swash plate 8 is maximized (the state shown in FIG. 1), the outer spring 51a is compressed by the first spring seat 31 and the second spring seat 36, while the inner spring 51b That end portion is separated from the spring seat (the first spring seat 31 in FIG. 1) and is in a floating state (a state of a natural length). That is, when the tilting angle of the swash plate 8 decreases from the maximum state, only the outer spring 51a is initially compressed, and if 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 forces from the outer springs 51a and the inner springs 51b applied to the swash plate 8 via the first spring seat 31 are increased stepwise.

As described above, the support springs 30, the outer springs 51a and the inner springs 51b are provided adjacent to each other in parallel with the swash plate 8. More specifically, the outer spring 51 a and the inner spring 51 b are provided radially inside the support spring 30 . Furthermore, the biasing force of the support spring 30 and the biasing forces of the outer springs 51a and the inner springs 51b are configured to act on the swash plate 8 in parallel.

A spool housing hole 50a into which the control spool 52 is slidably inserted is formed in the case body 3a. The spool accommodation hole 50a opens in the end face 3g of the case main body 3a. The opening of the spool accommodation hole 50a with respect to the end face 3g of the case body 3a is closed by a bottomed cylindrical auxiliary case portion 3f attached to the end face 3g of the case body 3a.

Further, a discharge pressure passage 10 through which the discharge pressure of the piston pump 100 is guided, and a control pressure passage 11 through which the control pressure is guided to the control pressure chamber 23 of the control piston 22 are formed in the case body 3a. The discharge pressure of the piston pump 100 is always led to the discharge pressure passage 10 . The control pressure passage 11 communicates with the control pressure chamber 23 through a cover-side passage (not shown) formed in the cover 3b. In FIG. 1, dashed lines schematically show lines that lead the discharge pressure of the piston pump 100 to the discharge pressure passage 10 and a signal pressure passage 12, which will be described later.

As shown in FIG. 2, the control spool 52 includes a main body portion 53 that slides on the inner peripheral surface of the spool housing hole 50a, and a flange that is provided at one end of the main body portion 53 and has a larger outer diameter than the main body portion 53. and a protruding portion 55 provided at the other end of the body portion 53 opposite to the flange portion 54 and inserted into the second spring seat 36 .

The flange portion 54 protrudes from the spool accommodation hole 50a to the outside of the case main body 3a and is accommodated in the auxiliary case portion 3f. The projecting portion 55 is formed to have an outer diameter smaller than that of the main body portion 53 , and a step surface 55 a caused by the difference in outer diameter between the main body portion 53 and the projecting portion 55 contacts the second spring seat 36 .

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. A control passage 57 communicating with the first control port 56a is formed in the control spool 52 so as to penetrate the control spool 52 in the radial direction. Further, the control spool 52 is formed with an axial passage 58 extending axially from one end (projection 55). The axial passage 58 communicates the control passage 57 with the connection passage 36a formed in the second spring seat 36 and opening into the case body 3a.

Thus, the control passage 57 communicates with the interior of the case 3 through the axial passage 58 and the connection passage 36 a of the second spring seat 36 . Therefore, the pressure in the control passage 57 becomes the tank pressure.

The auxiliary biasing portion 60 includes an auxiliary spring 61 as an auxiliary biasing member, a first seat portion 70 on which the end portion of the auxiliary spring 61 is seated, and an accommodation chamber 65 formed in the auxiliary case portion 3f and accommodating the auxiliary spring 61. and an adjustment mechanism 80 that adjusts the biasing force exerted by the auxiliary spring 61 .

The housing chamber 65 is formed by a housing recess 66 formed in the auxiliary case portion 3f. The housing recess 66 is formed as a bottomed cylindrical recess that opens to the end surface (mounting surface) 3h of the auxiliary case portion 3f attached to the end surface 3g of the case main body 3a. That is, the opening of the housing recess 66 is sealed by the end surface 3g of the case body 3a.

The accommodation recessed portion 66 includes a first recessed portion 66a that opens to the mounting surface 3h of the auxiliary case portion 3f, a second recessed portion 66b that communicates with the first recessed portion 66a and has an inner diameter smaller than that of the first recessed portion 66a, and a and a step surface 66c formed by a difference in inner diameter from the second recess 66b. The first recess 66a and the second recess 66b each have a circular cross-section formed coaxially with the spool receiving hole 50a.

The flange portion 54 of the control spool 52 is accommodated in the first recess 66a. The control spool 52 is movable in the direction toward the swash plate 8 (rightward in FIG. 2) against the biasing force of the outer spring 51a and the inner spring 51b until the flange portion 54 contacts the end face 3g of the case body 3a. is. That is, the end surface 3g of the case body 3a functions as a stopper portion, and the flange portion 54 comes into contact with the end surface 3g of the case body 3a as the control spool 52 moves, so that the control spool moves further toward the swash plate 8. 52 movement is restricted (see FIG. 3).

Further, the control spool 52 is biased by the outer spring 51a and the inner spring 51b until the flange portion 54 abuts on the stepped surface 66c of the housing recess 66 of the auxiliary case portion 3f in the direction away from the swash plate 8 (see FIG. 2). left direction). When the tilting angle of the swash plate 8 is maximum as shown in FIGS. 1 and 2, the flange portion 54 of the control spool 52 contacts the step surface 66c of the auxiliary case portion 3f. That is, the inner diameter of the first recess 66 a of the housing recess 66 is larger than the inner diameter of the flange portion 54 , and the inner diameter of the second recess 66 b is smaller than the inner diameter of the flange portion 54 .

The auxiliary spring 61 is a coil spring and is provided in a compressed state between the first seating portion 70 and the end surface of the flange portion 54 of the control spool 52 . That is, the auxiliary spring 61 directly contacts the control spool 52 and applies a biasing force. Auxiliary spring 61 is provided to exert a biasing force in a direction along the movement direction of control spool 52 .

A communication passage 54a is formed on the end surface of the flange portion 54 on which the auxiliary spring 61 is seated, the both ends of which are open to the outer peripheral surface of the flange portion 54 . The communication path 54 a is a slit formed extending in the radial direction of the flange portion 54 . As a result, even when the flange portion 54 is in contact with the step surface 66c, the inner side of the first recessed portion 66a and the inner side of the second recessed portion 66b communicate with each other through the communication path 54a. Therefore, the accommodation chamber 65 (accommodation concave portion 66) is prevented from being separated into two chambers due to the contact of the flange portion 54 with the step surface 66c.

It should be noted that the communication path is not limited to the slit provided on the end surface of the flange portion 54 . For example, a slit may be formed in the step surface 66c of the housing recess 66. FIG. Further, a through hole axially penetrating the flange portion 54 may be used as the communicating passage, or a passage formed over the body portion 53 and the flange portion 54 of the control spool 52 may be used as the communicating passage. Thus, the communication path is provided in at least one of the auxiliary case portion 3f and the control spool 52 so as to communicate the first recessed portion 66a and the second recessed portion 66b with the flange portion 54 in contact with the stepped surface 66c. Anything that can be done is acceptable.

The first seating portion 70 is housed in the second recess 66b of the housing recess 66. The first seat portion 70 includes a disk portion 71 provided with a seating surface 71a on which one end of the auxiliary spring 61 is seated, and a projection portion 72 that protrudes from the seating surface 71a of the disk portion 71 and supports the auxiliary spring 61 from the inside. , has A seal member (not shown) is provided on the outer circumference of the disk portion 71 to seal the gap between the disc portion 71 and the inner circumference of the second concave portion 66b.

As shown in FIG. 2, the adjustment mechanism 80 is configured to be screwed into a female threaded hole 81 formed in the bottom of the auxiliary case portion 3f and to move the first seating portion 70 along the biasing direction of the auxiliary spring 61. It has a threaded member 82 that advances and retreats, and a nut 83 that fixes the threaded position of the threaded member 82 with respect to the female threaded hole 81 .

The female screw hole 81 penetrates through the bottom of the auxiliary case portion 3f and opens into the second recess 66b. The screw member 82 abuts on the first seat portion 70 from the side axially opposite to the side on which the auxiliary spring 61 is seated. The threaded member 82 advances and retreats with respect to the first seat portion 70 along its axial direction (the direction of the biasing force of the auxiliary spring 61) by adjusting the threaded position with the female threaded hole 81. As shown in FIG. That is, by advancing and retreating the screw member 82, the first seat portion 70 advances and retreats so that the auxiliary spring 61 expands and contracts, and the set load (initial load) of the auxiliary spring 61 can be adjusted. Thereby, the biasing force exerted by the auxiliary spring 61 is configured to be adjustable. By screwing the nut 83 onto the threaded member 82 and tightening the auxiliary case portion 3f, the threaded position of the threaded member 82 with respect to the female threaded hole 81 is fixed.

The biasing force (set load) of the auxiliary spring 61 is desirably adjusted within a range that does not exceed the resultant force of the biasing forces of the outer springs 51a and the inner springs 51b. This prevents unintended movement of the control spool 52 caused by the compression of the outer spring 51a and the inner spring 51b when the biasing force of the auxiliary spring 61 is adjusted.

Further, a signal pressure passage 12 for guiding signal pressure to the housing chamber 65 is formed in the case body 3a. The signal pressure passage 12 is formed to open in the end face 3g of the case main body 3a so as to face the first recess 66a of the housing recess 66. As shown in FIG. In this embodiment, the discharge pressure (self-pressure) of the piston pump 100 is guided to the housing chamber 65 as the signal pressure corresponding to the load of the drive source. By guiding the signal pressure to the housing chamber 65 , a thrust due to the signal pressure acts on the control spool 52 through the first seating portion 70 and the transmission pin 63 . The direction of the thrust due to the signal pressure acting on the control spool 52 is the same direction as the auxiliary spring 61, that is, the direction to move the control spool 52 so as to compress the outer spring 51a and the inner spring 51b. In this manner, the accommodation chamber 65 accommodates the auxiliary spring 61 and also functions as a signal pressure chamber that exerts a thrust force on the control spool 52 by receiving the signal pressure.

The signal pressure passage 12 is desirably constructed so as not to be blocked by the flange portion 54 that contacts the end face 3g of the case body 3a. Specifically, for example, the signal pressure passage 12 may be configured to open to the end face 3g of the case main body 3a at a position radially outside the flange portion 54 . In addition, a slit extending in the radial direction is formed in the flange surface of the flange portion 54 that abuts on the end surface 3g of the case body 3a, or a passage that penetrates the flange portion 54 in the axial direction is formed. The signal pressure passage 12 and the first recess 66a may be configured to communicate with each other.

Further, even when the flange portion 54 is in contact with the stepped surface 66c of the housing recess 66, the first recess 66a and the second recess 66b are not blocked, so that the signal pressure passage 12 can be either the first recess 66a or the second recess 66b. It may be formed in the auxiliary case portion 3f so as to open to the two recesses 66b. Thus, in this embodiment, the degree of freedom in designing the position where the signal pressure passage 12 is formed is improved. As in the present embodiment, the signal pressure passage 12 is formed so as to open at the end face of the case main body 3a, and the signal pressure passage 12 is not formed in the auxiliary case portion 3f. There is no need to secure a space for forming 12 in the auxiliary case portion 3f. Therefore, the size of the auxiliary case portion 3f can be reduced.

As described above, the control spool 52 is biased away from the swash plate 8 (to the left in the drawing) by the biasing force of the outer spring 51a and the inner spring 51b. The control spool 52 is urged toward the swash plate 8 by the urging force of the auxiliary spring 61 and the thrust of the discharge pressure (signal pressure) of the piston pump 100 guided to the housing chamber 65 . That is, the control spool 52 moves so that the urging forces due to the outer spring 51a, the inner spring 51b, the auxiliary spring 61, and the discharge pressure of the piston pump 100 are balanced.

Specifically, the control spool 52 moves between two positions, a first position and a second position. 1 and 2 show the control spool 52 in the second position. The control spool 52 switches from the second position shown in FIGS. 1 and 2 to the first position shown in FIG. 3 as it moves rightward in the drawings.

The first position is a position in which the tilting angle of the swash plate 8 is reduced to reduce the displacement of the piston pump 100 . In the first position, the discharge pressure passage 10 of the case body 3a and the control pressure passage 11 are communicated through the second control port 56b of the control spool 52, and the control passage 57 of the control spool 52 and the control pressure passage 11 are not communicated. blocked. Therefore, in the first position, the discharge pressure of the piston pump 100 is introduced to the control pressure chamber 23 of the first biasing portion 20 .

The second position is a position in which the displacement of the piston pump 100 is increased by increasing the tilt angle of the swash plate 8 . In the second position, the control pressure passage 11 and the control passage 57 of the control spool 52 are communicated through the first control port 56a, and communication between the discharge pressure passage 10 and the control pressure passage 11 is blocked. Therefore, in the second position, tank pressure is introduced to the control pressure chamber 23 .

Next, the action of the piston pump 100 will be explained.

In the piston pump 100, the regulator 50 performs horsepower control to control the discharge capacity of the piston pump 100 (tilting angle of the swash plate 8) so as to keep the discharge pressure of the piston pump 100 constant.

The control spool 52 of the regulator 50 is urged to the first position by the urging force of the auxiliary spring 61 and the urging force of the discharge pressure of the piston pump 100 led to the housing chamber 65 . Also, the control spool 52 is biased to the second position by the biasing forces of the outer spring 51a and the inner spring 51b.

When the discharge pressure of the piston pump 100 and the biasing force of the auxiliary spring 61 are kept below the biasing force of the outer spring 51a, the control spool 52 of the regulator 50 is positioned at the second position and the tilt angle of the swash plate 8 is kept at a maximum (see Figure 1).

The discharge pressure of the piston pump 100 increases as the load on the hydraulic cylinder driven by the discharge pressure of the piston pump 100 increases. When the discharge pressure of the piston pump 100 increases from the state in which the tilt angle of the swash plate 8 is maintained at the maximum, the resultant force of the discharge pressure and the biasing force of the auxiliary spring 61 exceeds the biasing force of the outer spring 51a. As a result, the control spool 52 moves in the direction of switching from the second position to the first position (rightward in the drawing).

As shown in FIG. 3, when the control spool 52 moves to the first position, the discharge pressure is led from the discharge pressure passage 10 to the control pressure passage 11, so 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, the control pressure introduced to the control pressure passage 11 increases as the amount of movement of the control spool 52 in the direction of switching to the first position (rightward direction in the drawing) increases. As the control pressure guided to the control pressure passage 11 rises, the control piston 22 (see FIG. 1) moves toward the swash plate 8, and the swash plate 8 tilts in the direction of decreasing the tilt angle. Therefore, the displacement of the piston pump 100 is reduced.

When the swash plate 8 tilts in the direction of decreasing the tilt angle, the first spring seat 31 follows the swash plate 8 and moves leftward in the drawing 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 of decreasing the tilt angle, the first spring seat 31 biases the control spool 52 through the outer spring 51a (and the inner spring 51b) in the direction of switching to the second position. to move. 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 23 through the control pressure passage 11 decreases. As the control pressure decreases, when the biasing force applied to the swash plate 8 by the control pressure balances the biasing force applied to the swash plate 8 from the outer spring 51a (and the inner spring 51b), the movement of the control piston 22 ( tilting of the swash plate 8) stops. Thus, when the discharge pressure of piston pump 100 increases, the discharge capacity decreases.

Conversely, the discharge pressure of the piston pump 100 decreases as the load on the hydraulic cylinder driven by the discharge pressure of the piston pump 100 decreases. When the discharge pressure of piston pump 100 decreases, the resultant force of the discharge pressure of piston pump 100 and the biasing force acting on control spool 52 by auxiliary spring 61 becomes less than the biasing force of outer spring 51a and inner spring 51b. This causes the control spool 52 to move 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 decreases because the control pressure passage 11 communicates with the control passage 57, which is the tank pressure. As the control pressure decreases, the swash plate 8 is tilted in the direction in which the tilt angle is increased by the first spring seat 31 which receives the biasing force of the outer spring 51a and the inner spring 51b.

When the swash plate 8 tilts in the direction in which the tilt angle increases, the first spring seats 31, which receive the biasing forces of the outer springs 51a and the inner springs 51b, move the swash plate so that the outer springs 51a and the inner springs 51b extend. 8 and moves rightward in the figure. As a result, the biasing force that the control spool 52 receives from the outer spring 51a and the inner spring 51b is reduced. Therefore, the control spool 52 receives the discharge pressure guided to the housing chamber 65 and the biasing force of the auxiliary spring 61, 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 first spring seat 31 . The control spool 52 is again positioned at the first position, the control pressure increases, and the biasing 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 the forces are balanced, movement of the control piston 22 (tilting of the swashplate 8) stops. Thus, when the discharge pressure of piston pump 100 decreases, the discharge capacity increases.

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

The control spool 52 moves so that the urging force due to the discharge pressure (self-pressure) of the piston pump 100, the urging force exerted by the outer spring 51a and the inner spring 51b, and the urging force exerted by the auxiliary spring 61 are balanced. Adjust pressure. Thereby, the horsepower of the piston pump 100 is controlled. In other words, the characteristics of horsepower control by the regulator 50 are affected by the biasing force exerted by the outer spring 51a and the inner spring 51b, the biasing force exerted by the auxiliary spring 61, and the biasing force due to self-pressure. By providing a plurality of configurations for urging the control spool 52 in this way, the degree of freedom in designing for realizing various control characteristics can be improved, and desired control characteristics can be achieved with higher accuracy.

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

In the piston pump 100, the biasing force of the auxiliary spring 61 and the biasing force (thrust force) of the signal pressure act on the control spool 52, so that the regulator 50 facilitates various control characteristics. Further, the accommodation chamber 65 accommodates the auxiliary spring 61 and also functions as a signal pressure chamber that exerts a thrust force on the control spool 52 by receiving the signal pressure. Therefore, compared with the case where the signal pressure chamber is provided separately from the accommodation chamber 65, the device configuration can be made smaller. Therefore, in the piston pump 100, various control characteristics can be realized by the regulator 50 while suppressing an increase in size of the device.

In addition, in the piston pump 100, the end surface 3h of the auxiliary case portion 3f where the accommodation recess 66 opens is attached to the end surface 3g of the case main body 3a. Therefore, since the signal pressure passage 12 need not be formed in the auxiliary case portion 3f but formed in the case body 3a, the size of the auxiliary case portion 3f can be reduced. Alternatively, the signal pressure passage 12 may be formed across the case main body 3a and the auxiliary case portion 3f and open to the first recess 66a or the second recess 66b that defines the housing chamber 65. As shown in FIG. As described above, according to the piston pump 100, it is possible to arbitrarily set how the signal pressure passage 12 is connected to the housing chamber 65, so that the degree of freedom in design is improved.

In addition, since the opening of the accommodation recess 66 in the auxiliary case portion 3f is closed by the end face 3g of the case main body 3a, there is no need to separately provide a cap, plug, or the like for sealing the opening of the accommodation recess 66. Points can be reduced.

Next, a modification of the first embodiment will be described with reference to FIG.

The control spool 52 slides with a predetermined sliding clearance with respect to the spool accommodation hole 50a. For this reason, in the first embodiment, there is a possibility that hydraulic fluid will flow through the sliding clearance between the housing chamber 65 and the discharge pressure passage 10 . When there is a pressure difference between the housing chamber 65 and the discharge pressure passage 10, hydraulic fluid is particularly likely to flow through the sliding clearance.

In the first embodiment, in order to suppress the flow of hydraulic fluid between the storage chamber 65 and the discharge pressure passage 10 through such a sliding clearance, a drain chamber for discharging hydraulic fluid is provided as shown in FIG. 13 may be formed. The drain chamber 13 is connected to, for example, a tank. The drain chamber 13 is annularly formed on the inner periphery of the spool accommodation hole 50a on the opening side (left side in FIG. 4) of the spool accommodation hole 50a relative to the discharge pressure passage 10 in the axial direction of the control spool 52. As shown in FIG. As a result, even if hydraulic fluid flows between the storage chamber 65 and the discharge pressure passage 10 through the sliding clearance, it can be discharged through the drain chamber 13 .

(Second embodiment)
Next, a piston pump 200 according to a second embodiment of the invention will be described with reference to FIGS. 5 and 6. FIG. In the following, the points different from the first embodiment will be mainly described, and the same reference numerals will be given to the same configurations as in the first embodiment, and the description will be omitted.

In the first embodiment, the auxiliary spring 61 directly contacts the flange portion 54 of the control spool 52 and exerts a biasing force on the control spool 52 .

On the other hand, in the second embodiment, the auxiliary biasing portion 160 includes a transmission pin 63 as a transmission portion for transmitting the biasing force of the auxiliary spring 61 to the control spool 52 and a second spring on which the end portion of the auxiliary spring 61 is seated. It further has a seating portion (seat portion) 75 . That is, in the second embodiment, the biasing force of the auxiliary spring 61 is exerted on the control spool 52 through the transmission pin 63 .

The configuration of the second embodiment will be specifically described below.

As shown in FIG. 5, in the second embodiment, the spool housing hole 50a opens to the end face 3g of the case body 3a through the end recess 50b. The end recessed portion 50b is a circular hole having an inner diameter larger than the inner diameter of the spool accommodation hole 50a. A stepped surface 50c is formed by the difference in inner diameter between the spool accommodation hole 50a and the end recessed portion 50b.

The flange portion 54 of the control spool 52 is housed in the end recess portion 50b. Further movement of the control spool 52 toward the swash plate 8 is restricted by the contact of the flange portion 54 with the step surface 50c. That is, in the second embodiment, the step surface 50c functions as a stopper portion.

The opening of the end concave portion 50b with respect to the case main body 3a is closed by the bottomed cylindrical auxiliary case portion 3f. In the second embodiment, the auxiliary case portion 3f is attached to the end face 3g of the case main body 3a at the bottom end face 3i opposite to the end face where the accommodation recess 66 opens. Further movement of the control spool 52 in the direction away from the swash plate 8 is restricted by coming into contact with the end face 3i on the bottom side of the auxiliary case portion 3f.

The accommodation recess 66 of the auxiliary case portion 3f opens on the side opposite to the end face 3i of the auxiliary case portion 3f attached to the case main body 3a. In the second embodiment, the housing recess 66 is formed as a circular hole with a uniform inner diameter along the axial direction. As in the first embodiment, the housing recess 66 is formed coaxially with the spool housing hole 50a. The opening of the accommodation recess 66 is sealed by a cap 90 having an O-ring (not shown) attached to the outer circumference thereof as a sealing member.

A signal pressure passage 12 that opens to the housing recess 66 is formed in the auxiliary case portion 3f. Accordingly, the signal pressure is introduced through the signal pressure passage 12 to the accommodation chamber 65 formed by the accommodation recess 66 .

The first seating portion 70 is accommodated in a cap hole 90a formed in the cap 90. Also, the cap 90 is provided with an adjustment mechanism 80 . A female threaded hole 81 of the adjusting mechanism 80 is formed in the cap 90 . By screwing the nut 83 onto the threaded member 82 and tightening the cap 90 , the threaded position of the threaded member 82 with respect to the female threaded hole 81 is fixed.

The second seat portion 75 is movably accommodated in the accommodation chamber 65 together with the auxiliary spring 61 . The second seat portion 75 moves within the housing chamber 65 as the auxiliary spring 61 expands and contracts in accordance with the movement of the control spool 52 .

The second seat portion 75 includes a disk portion 76 provided with a seating surface 76a on which the other end of the auxiliary spring 61 is seated, and a projecting portion 77 that protrudes from the seating surface 76a of the disk portion 76 and supports the auxiliary spring 61 from the inside. , has

The outer diameter of the disk portion 76 of the second seating portion 75 is formed smaller than the inner diameter of the housing recess 66 of the auxiliary case portion 3f. Therefore, between the outer circumference of the second seating portion 75 and the inner wall of the accommodation chamber 65 (the inner peripheral surface of the accommodation recess 66), there is a gap in the radial direction (in other words, the direction perpendicular to the moving direction of the control spool 52). is provided. As a result, the second seat portion 75 can move in the accommodation chamber 65 along the movement direction of the control spool 52 without interfering with the inner wall of the accommodation chamber 65 , and the force is transmitted from the auxiliary spring 61 to the control spool 52 . It is possible to suppress the loss of the biasing force.

The transmission pin 63 is provided between the second seat portion 75 and the control spool 52, and is slidably inserted into a pin hole 65b formed in the bottom portion of the housing recess 66 of the auxiliary case portion 3f. The pin hole 65 b is formed coaxially with the housing recess 66 and one end opens into the housing recess 66 . The other end of the pin hole 65b opens to the end surface of the auxiliary case portion 3f facing the end surface of the case main body 3a.

As shown in FIG. 6, the transmission pin 63 is a substantially cylindrical member, and has a pair of spherical contact portions 63a and 63b at both ends thereof. One contact portion 63a contacts the second seat portion 75 with a spherical outer surface. The other contact portion 63b contacts the end surface of the flange portion 54 of the control spool 52 with its spherical outer surface. Thus, the force transmitted from the auxiliary spring 61 by the second seat 75 and the transmission pin 63 acts on the flange portion 54 of the control spool 52 .

Next, the action of the spherical contact portions 63a and 63b will be described with reference to FIG. FIG. 7 is an enlarged schematic view of the contact portion of the contact portion 63a of the transmission pin 63 when the disc portion 76 of the second seat portion 75 is tilted. Also, in FIG. 7, the dashed line indicates a transmission pin 163 as a comparative example which does not have the contact portion 63a and the end portion is formed as a flat surface perpendicular to the central axis, and the transmission pin 163 contacts the transmission pin 163. and a second seating portion 75 . In FIG. 7, the transmission pin 63 of the embodiment and the transmission pin 163 of the comparative example are illustrated so that their axial positions (end positions) are the same.

In the transmission pin 163 of the comparative example in which the end portion (end surface) is formed as a flat surface, the flat surface of the transmission pin 163 and the disk portion 76 of the second seating portion 75 are not tilted when the second seating portion 75 is not inclined. Surface contact with the end face. On the other hand, as shown in FIG. 7, in the comparative example, even if the second seating portion 75 is slightly inclined, the transmission pin 163 does not reach the outer peripheral edge of the end (the boundary between the flat surface and the outer cylindrical surface). portion) contacts the disc portion 76 .

On the other hand, in this embodiment, even if the second seating portion 75 is tilted, it is tilted along the spherical surface of the contact portion 63a. Therefore, in the transmission pin 63 of the present embodiment, the contact portion with the disk portion 76 is not the outer peripheral portion as in the comparative example, but the spherical surface portion radially inward thereof. For this reason, for example, assuming that one point on the edge of the opening of the pin hole 65b is a reference point P0 as shown in FIG. is smaller than the distance L2 between the contact point P2 between the transmission pin 163 and the disc portion 76 and the reference point P0 in the comparative example (L1<L2). Therefore, the force acting around the reference point P0 is smaller in the transmission pin 63 of this embodiment than in the comparative example. Therefore, even if the second seat portion 75 tilts in the housing chamber 65, the force that presses against the pin hole 65b is suppressed, and the increase in friction between the transmission pin 63 and the pin hole 65b is relatively small. . Therefore, the transmission pin 63 can be moved smoothly, and as a result, the force can be efficiently transmitted to the control spool 52 .

The number of transmission pins 63 is not limited to one, and a plurality may be provided. If multiple transmission pins 63 are provided, multiple transmission pins 63 may be provided equidistantly or equiangularly spaced from the central axis of the control spool 52 to balance the forces so that the control spool 52 does not tilt. Locating the pin 63 is desirable.

In the second embodiment as described above, similarly to the first embodiment, the accommodation chamber 65 accommodates the auxiliary spring 61 and functions as a signal pressure chamber to which the signal pressure is guided to exert a thrust force on the control spool 52. also works. Therefore, various control characteristics of the regulator 50 can be realized while suppressing an increase in size of the device.

Further, in the second embodiment, the biasing force due to the signal pressure in the accommodation chamber 65 is exerted on the control spool 52 according to the cross-sectional area (pressure receiving area) of the transmission pin 63 . That is, since the biasing force due to the signal pressure in the housing chamber 65 can be adjusted by the cross-sectional area of the transmission pin 63, the degree of freedom in design is improved, and the regulator 50 can easily exhibit various control characteristics. Further, for example, by setting the signal pressure guided into the housing chamber 65 to a relatively high pressure and by making the cross-sectional area of the transmission pin 63 relatively small, the piston pump 200 can be prevented from increasing in size while the pressure inside the housing chamber 65 is reduced. A sufficient biasing force can be exerted by the pressure of .

Also, in the piston pump 200 , a gap is provided between the outer circumference of the second seat portion 75 of the regulator 50 and the inner wall of the housing chamber 65 in the direction perpendicular to the moving direction of the control spool 52 . As a result, the inner wall of the housing chamber 65 does not interfere with the movement of the second seat portion 75, so that the loss of the biasing force transmitted from the auxiliary spring 61 to the control spool 52 can be suppressed.

In addition, there is a risk that the control spool will be tilted with respect to the moving direction due to the presence of a gap between the outer circumference of the second seating portion and the inner wall of the housing chamber. By tilting the second seat portion, the transmission pin is tilted in the pin hole to increase the frictional force between the transmission pin and the auxiliary case portion, and the direction of the force transmitted from the transmission pin to the control spool can be controlled. There is a risk that it will be tilted with respect to the movement direction of the spool.

On the other hand, in the present embodiment, the transmission pin 63 contacts the second seating portion 75 and the control spool 52 through spherical contact portions 63a and 63b. Therefore, even if the second seat portion 75 is tilted in the housing chamber 65, it is tilted with respect to the transmission pin 63 along the spherical surface of the contact portion 63a. It is possible to relatively suppress the pressing force. Therefore, the loss of the biasing force of the auxiliary spring 61 between the transmission pin 63 and the auxiliary case portion 3f is suppressed, and the biasing force of the auxiliary spring 61 is transmitted through the second seating portion 75 and the transmission pin 63 in the moving direction of the control spool 52. can be efficiently transmitted along

Also, in the piston pump 200 , the force transmitted from the transmission pin 63 acts on the flange portion 54 . Since the flange portion 54 functions as a stopper against the movement of the control spool 52 and has a larger outer diameter and a larger cross-sectional area than the body portion 53 of the control spool 52, it is easy to secure a pressure receiving area. Therefore, it becomes easy to increase the diameter of the transmission pin 63 or to provide a plurality of transmission pins 63, and it is easy to increase the pressure receiving area of the signal pressure and secure the thrust due to the signal pressure. Therefore, the degree of freedom of the control characteristics of the horsepower control of the regulator 50 can be further improved.

In addition, in the piston pump 200, the portion that slides due to the signal pressure in the accommodation chamber 65 is only one portion between the transmission pin 63 and the pin hole 65b. can be suppressed.

(Third embodiment)
Next, a piston pump 300 according to a third embodiment of the invention will be described with reference to FIG. In the following, the points different from the above-described second embodiment will be mainly described, and the same reference numerals will be given to the same configurations as in the above-described second embodiment, and the description thereof will be omitted. Specifically, in the third embodiment, only the configuration of the auxiliary biasing portion 260 differs from the configuration of the auxiliary biasing portion 160 of the second embodiment, and other configurations are the same.

In the third embodiment, the auxiliary biasing portion 260 includes a pair of transmission pins 63, as shown in FIG. Further, in the third embodiment, the auxiliary urging portion 260 includes the signal pressure chamber 67 to which the second signal pressure different from the signal pressure to be guided to the accommodation chamber 65 is guided, and the signal pressure chamber 67 to which the second signal pressure is applied. and a second transmission pin 68 as a thrust force transmission portion that transmits the thrust exerted by being guided to the control spool 52 .

The pair of transmission pins 63 are provided at symmetrical positions with respect to the central axis of the control spool 52 . Pin holes 65b are formed in the auxiliary case portion 3f so as to correspond to the positions of the pair of transmission pins 63. As shown in FIG.

An insertion hole 65c for forming a signal pressure chamber 67 is formed in the end face of the auxiliary case portion 3f facing the case main body 3a. A second transmission pin 68 is slidably inserted into the insertion hole 65c. The insertion hole 65 c is a bottomed circular hole, and a signal pressure chamber 67 is formed between the bottom of the insertion hole 65 c and the end of the transmission pin 63 . The insertion hole 65c is formed coaxially with the spool accommodation hole 50a and faces the end recess 50b of the spool accommodation hole 50a.

The length along the axial direction of the second transmission pin 68 is formed shorter than the depth (dimension along the axial direction) of the insertion hole 65c. As a result, the control spool 52 can move until it abuts against the end face of the auxiliary case portion 3f. A signal pressure chamber 67 is formed between .

Further, a signal pressure passage 12 that guides signal pressure to the signal pressure chamber 67 is formed in the auxiliary case portion 3f. In the third embodiment, the signal pressure led to the housing chamber 65 is the external pump pressure discharged from another hydraulic pump driven by the power source together with the piston pump 300, and the second pressure led to the signal pressure chamber 67. The signal pressure is the discharge pressure (self-pressure) of piston pump 300 . By introducing the second signal pressure to the signal pressure chamber 67 , thrust based on the second signal pressure acts on the control spool 52 through the second transmission pin 68 .

In the third embodiment, similarly to the second embodiment, the control spool 52 is urged away from the swash plate 8 (leftward in the figure) by the urging forces of the outer spring 51a and the inner spring 51b. Further, the control spool 52 is controlled by the biasing force of the auxiliary spring 61, the thrust force of the external pump pressure (signal pressure) guided to the housing chamber 65, and the discharge pressure of the piston pump 100 guided to the second signal pressure chamber (second 2 signal pressure), and is urged in the direction toward the swash plate 8 . That is, the control spool 52 moves so that the urging forces due to the outer spring 51a and the inner spring 51b, the auxiliary spring 61, the discharge pressure of the piston pump 300, and the external pump pressure are balanced.

Compared with the second embodiment, in the third embodiment, the discharge pressure of the piston pump 300 and the external pump pressure as the signal pressure exert a thrust to energize the control spool 52, respectively, so more complex horsepower control characteristics are realized. can do. In the third embodiment, in addition to the second embodiment in which the discharge pressure of the piston pump 300 is derived, the control spool 52 is also urged towards the swashplate 8 by external pump pressure. In this way, since the thrust due to the self-pressure is compensated for by the external pump pressure, in the third embodiment, the self-pressure at which horsepower control is executed is smaller than in the second embodiment by the magnitude of the external pump pressure. . Thus, in the third embodiment, more mechanisms for urging the control spool 52 are provided than in the second embodiment, so that the degree of freedom in designing horsepower control characteristics is improved.

It should be noted that in the third embodiment, the number of transmission pins 63 is not limited to one pair, and may be singular or three or more. Also, the number of the second transmission pins 68 is not limited to one, and may be plural.

Further, in the third embodiment, the self-pressure may be guided to the accommodation chamber 65 and the external pump pressure may be guided to the signal pressure chamber 67 . Further, the signal pressure led to the accommodation chamber 65 and the second signal pressure led to the signal pressure chamber 67 are not limited to those in the above embodiment, and may be other pressures. For example, the second signal pressure led to the signal pressure chamber 67 may be a self-pressure or an external pump pressure adjusted by a solenoid valve. Also, the second signal pressure may be configured to switch between supply and cutoff to the signal pressure chamber 67 by an ON-OFF valve.

(Fourth embodiment)
Next, a piston pump 400 according to a fourth embodiment of the invention will be described with reference to FIG. In the following, the points different from the first embodiment will be mainly described, and the same reference numerals will be given to the same configurations as in the first embodiment, and the description will be omitted.

In the first embodiment described above, the regulator 50 performs horsepower control that adjusts the control pressure according to the load of the drive source that drives the piston pump 100 . Specifically, the self-pressure of the piston pump 100 is directly guided to the housing chamber 65 of the regulator 50 as the signal pressure.

On the other hand, in the piston pump 400 according to the fourth embodiment, as shown in FIG. The pressure is derived as the signal pressure.

The opening degree of the electromagnetic proportional pressure reducing valve 101 is adjusted, for example, by an electric signal output from the controller 102 according to the operator's operation. By adopting such a configuration, it is possible to control the tilting angle of the swash plate 8 by an electric signal, so that arbitrary control characteristics can be realized according to the operator's operation. In other words, the piston pump 400 according to the fourth embodiment does not perform horsepower control, and the piston pump according to the present invention is not limited to one in which horsepower control is performed.

In the piston pump 400 according to the fourth embodiment, as shown in FIG. 9, the biasing member is preferably composed of a single spring 51c. According to this, by proportionally controlling the electromagnetic proportional pressure reducing valve 101 corresponding to the linear characteristic of the spring 51c, the control can be easily performed.

Further, in the fourth embodiment, a high pressure selection valve 104 is provided to select the higher pressure from the pressure supplied from the hydraulic source 103 and the self pressure of the piston pump 400 and guide it to the discharge pressure passage 10 . As a result, even when the self-pressure of the piston pump 400 is relatively low, for example, when the piston pump 400 is started, a predetermined pressure is guided to the discharge pressure passage 10 by the hydraulic source 103 . tilt angle can be controlled.

As in the first embodiment, the self-pressure of the piston pump 400 or the pressure of the hydraulic source 103 such as a gear pump may be guided to the discharge pressure passage 10 alone without providing the high pressure selection valve 104 . Also, the hydraulic pressure source 103 and the high pressure selection valve 104 may be applied to the first to third embodiments.

Also, the fourth embodiment in which the signal pressure is generated by the electromagnetic proportional pressure reducing valve 101 may perform horsepower control in the same manner as in the first, second, and third embodiments. Specifically, the opening degree of the electromagnetic proportional pressure reducing valve 101 is adjusted according to the load of the drive source of the piston pump 400, the pressure of the hydraulic pressure source 103 or the self pressure is reduced to generate the signal pressure, and the signal pressure is reduced. Horsepower control can be performed by introducing the pressure to the accommodation chamber 65 . For example, when the drive source is an engine, the controller 102 calculates the load of the drive source from the engine torque, engine speed, etc., adjusts the opening of the electromagnetic proportional pressure reducing valve 101 based on the load, and generates the signal pressure. and may be led to the containment chamber 65 . Further, for example, when the drive source is an electric motor, the controller 102 calculates the load of the drive source from the torque or rotation speed of the electric motor, adjusts the opening degree of the electromagnetic proportional pressure reducing valve 101 based on the load, and signals A pressure may be generated and directed to the containment chamber 65 . The horsepower control can be electrically controlled by adjusting the opening degree of the electromagnetic proportional pressure reducing valve 101 according to the load of the drive source to generate the signal pressure.

Thus, by adopting a configuration in which the signal pressure is generated by the electromagnetic proportional pressure reducing valve 101, it is possible to perform horsepower control by electrical control. Thus, tilt angle control of the swash plate 8 other than horsepower control can be performed. For example, in the second and third embodiments, the tilting angle of the swash plate 8 may be controlled by the electromagnetic proportional pressure reducing valve 101 instead of the horsepower control. Further, in the third embodiment, the second signal pressure may be the signal pressure generated by the electromagnetic proportional pressure reducing valve 101 based on the load of the drive source.

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

A piston pump 100, 200, 300, 400 includes a cylinder block 2 that rotates together with a shaft 1, a plurality of cylinders 2b that are formed in the cylinder block 2 and arranged at predetermined intervals in the circumferential direction of the shaft 1, and A piston 5 which is slidably inserted into the cylinder 2b and defines a volume chamber 6; a tiltable swash plate 8 which reciprocates the piston 5 so as to expand and contract the volume chamber 6; A first biasing portion 20 that biases the swash plate 8 accordingly, a second biasing portion 30 that biases the swash plate 8 against the first biasing portion 20, and the first biasing portion 20 and a regulator 50 for controlling the control pressure to be guided. a control spool 52 that moves in response to and adjusts the control pressure; an auxiliary biasing member (auxiliary spring 61) that exerts a biasing force against the control spool 52 so as to resist the biasing force of the biasing member; an accommodation chamber 65 for accommodating an auxiliary biasing member, into which a signal pressure is led to exert a thrust force on the control spool 52 against the biasing force of the biasing member.

In this configuration, the signal pressure is guided to the accommodation chamber 65 in which the auxiliary urging member that urges the control spool 52 is accommodated, so that the control spool 52 exerts a thrust force due to the signal pressure. In addition to accommodating the auxiliary biasing member, the accommodation chamber 65 also functions as a pressure chamber for exerting a thrust force according to the signal pressure. Can be made smaller. Therefore, even if a plurality of configurations for urging the control spool 52 are provided, it is possible to suppress an increase in the size of the device. Therefore, it is possible to improve the degree of freedom of the control characteristics of the regulator 50 while suppressing the enlargement of the piston pumps 100, 200, 300.

Further, in the piston pumps 100, 400 according to the first embodiment, the auxiliary biasing member directly contacts the control spool 52 and exerts biasing force.

With this configuration, the configuration can be simplified and the number of parts can be reduced.

Further, in the piston pumps 200 and 300 according to the second and third embodiments, the regulator 50 is provided in the housing chamber 65 so that one end of the auxiliary biasing member is seated and is movable along the movement direction of the control spool 52. It further has a seat portion (second seat portion 75 ) and a transmission portion (transmission pin 63 ) provided between the seat portion and the control spool 52 for transmitting the biasing force of the auxiliary biasing member to the control spool 52 .

With this configuration, the biasing force due to the signal pressure in the housing chamber 65 is exerted on the control spool 52 according to the cross-sectional area (pressure receiving area) of the transmission portion. That is, since the biasing force due to the signal pressure in the housing chamber 65 can be adjusted by the cross-sectional area of the transmission portion, the degree of freedom in design is improved, and various control characteristics can be easily exhibited by the regulator 50 .

Also, in the piston pumps 200 and 300 according to the second and third embodiments, the seating portion is provided with a gap from the inner wall of the housing chamber 65 in the direction perpendicular to the moving direction of the control spool 52 .

In this configuration, the seat portion moves within the storage chamber 65 without contacting the inner wall of the storage chamber 65, so that it is possible to suppress the influence of the control characteristics due to the frictional force generated between the seat portion and the storage chamber 65. .

In addition, in the piston pumps 200 and 300 according to the second and third embodiments, the transmission portion has the contact portion 63a which is formed in a spherical shape and contacts the seating portion.

In this configuration, even if the seat tilts in the storage chamber 65 due to the gap provided between the seat and the storage chamber 65, the contact portion 63a of the transmission portion with respect to the seat is spherical. Movement of the transmission pin 63 in the movement direction of the spool 52 is less likely to be hindered.

Further, in the piston pump 300 according to the third embodiment, the auxiliary biasing portion 260 includes the signal pressure chamber 67 to which the second signal pressure different from the signal pressure guided to the accommodation chamber 65 is guided, and the second signal pressure chamber 67 to which the second signal pressure is guided. is guided to the signal pressure chamber 67 to transmit the thrust exerted to the control spool 52 (the second transmission pin 68 ).

In this configuration, in addition to the biasing force of the auxiliary biasing member and the thrust due to the signal pressure, the thrust due to the second signal pressure acts on the control spool 52 . Therefore, more diverse control characteristics can be realized.

Further, the piston pumps 100, 200, 300, 400 have a case 3 provided with a spool housing hole 50a into which the control spool 52 is inserted. and a flange portion 54 provided at the end portion of the main body portion 53 and having an outer diameter larger than that of the main body portion 53, and a stopper portion formed in the case 3 (the end surface 3g of the case main body 3a, the step surface 50c). Further movement of the control spool 52 along the urging force exerted by the auxiliary urging member is restricted by the flange portion 54 coming into contact with the control spool 52 according to the movement of the auxiliary urging member. The thrust due to force and signal pressure is configured to act on the flange portion 54 .

According to this configuration, in the control spool 52 , the flange portion 54 having a relatively large cross-sectional area is provided at the end portion of the body portion 53 . By configuring the control spool 52 so that the force acting on the control spool 52 acts on the flange portion 54, it is possible to secure an area for the control spool 52 to receive the force. Therefore, it becomes easier to apply force to the control spool 52 by a plurality of configurations, and it is possible to realize more diverse control characteristics of horsepower control.

In addition, the signal pressure of the piston pump 400 is generated by the electromagnetic proportional pressure reducing valve 101 .

With this configuration, the tilt angle of the swash plate can be controlled by an electrical signal.

Although the embodiments of the present invention have been described above, the above embodiments merely show a part of application examples of the present invention, and the technical scope of the present invention is not limited to the specific configurations of the above embodiments. do not have.

In the first embodiment, the flange portion 54 of the control spool 52 is accommodated in the first concave portion 66a of the accommodating concave portion 66 of the auxiliary case portion 3f, and the end surface 3g of the case body 3a is a stopper portion that restricts the movement of the control spool 52. function as In the second and third embodiments, the flange portion 54 is accommodated in the end recess portion 50b of the case body 3a, and the step surface 50c between the end recess portion 50b and the spool accommodation hole 50a functions as a stopper portion. On the other hand, in the first embodiment, as in the second and third embodiments, the case main body 3a may be provided with the end recess 50b and the step surface 50c. Further, in the second and third embodiments, like the first recess 66a of the first embodiment, a recess may be provided in the end face facing the case body 3a to accommodate the flange portion 54. FIG. As described above, the concave portion for accommodating the flange portion 54 and the stopper portion with which the flange portion 54 abuts may be provided on the case 3, and may be provided on the case main body 3a, or may be provided on the auxiliary case portion 3f. may be In addition, recesses for accommodating the flange portion 54 may be provided in both the case main body 3a and the auxiliary case portion 3f.

Further, in the second and third embodiments, the transmission pin 63 and the second transmission pin 68 have spherical contact portions 63a, 63b, 68a. The configuration with spherical contact portions 63a, 63b, 68a is not essential, and the transmission pin 63 and the second transmission pin 68 are flat against the second seat 75 and the flange portion 54 of the control spool 52. Face-to-face contact may be used.

Further, in the second and third embodiments, a gap is provided in the radial direction of the control spool 52 between the outer circumference of the second seating portion 75 and the inner wall of the housing chamber 65 (the inner circumference of the housing recess 66). On the other hand, the second seating portion 75 may be in sliding contact with the inner periphery of the housing recess 66 . In this case, the accommodation chamber 65 is partitioned into two rooms by the second seating portion 75 . The two chambers may communicate with each other through a communication hole formed in the second seat portion 75 or may receive the same hydraulic pressure from each other by guiding the signal pressure from the signal pressure passage 12 . In addition, different signal pressures may be led to the two chambers partitioned in the accommodation chamber 65 by the second seat portion 75 . In this case, the pressure in the room (the room in which the transmission pin 63 is housed) partitioned between the second seating part 75 and the bottom part of the housing recess 66 out of the two rooms is set relative to the other room. A lower pressure should be used. With this configuration, even when the second seat portion 75 is in sliding contact with the housing recess 66, the biasing force of the auxiliary spring 61 is transmitted to the control spool 52 through the second seat portion 75 and the transmission pin 63. can do.

Claims (7)

1. A hydraulic rotary machine,
   a cylinder block rotating 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;
   a piston that is slidably inserted into the cylinder and defines a volume chamber inside the cylinder;
   a tiltable swash plate for reciprocating the piston so as to expand and contract the volume chamber;
   a first biasing portion that biases the swash plate according to the supplied control pressure;
   a second biasing portion biasing the swash plate against the first biasing portion;
   a regulator that controls the control pressure guided to the first biasing unit;
   The regulator
   a biasing member that expands and contracts following the tilting of the swash plate;
   a control spool that moves according to the biasing force of the biasing member to adjust the control pressure;
   an auxiliary biasing member exerting a biasing force against the control spool to resist the biasing force of the biasing member;
   a storage chamber that stores the auxiliary biasing member;
   A hydraulic rotating machine according to claim 1, wherein a signal pressure is led to the housing chamber to exert a thrust force on the control spool against the biasing force of the biasing member.
2. The hydraulic rotating machine according to claim 1,
   A hydraulic rotating machine, wherein the auxiliary biasing member exerts a biasing force by directly contacting the control spool.
3. The hydraulic rotating machine according to claim 1,
   The regulator
   a seating portion provided in the housing chamber on which one end of the auxiliary biasing member is seated and which is movably movable along the movement direction of the control spool;
   A hydraulic rotating machine, further comprising: a transmission section provided between the seating section and the control spool for transmitting the biasing force of the auxiliary biasing member to the control spool.
4. The hydraulic rotating machine according to claim 3,
   A hydraulic rotating machine, wherein the seat portion is provided with a gap from an inner wall of the housing chamber in a direction perpendicular to the moving direction of the control spool.
5. The hydraulic rotating machine according to claim 3 or 4,
   The hydraulic rotating machine, wherein the transmitting portion has a contact portion that is formed in a spherical shape and contacts the seating portion.
6. The hydraulic rotating machine according to any one of claims 1 to 4,
   Having a case provided with a spool accommodation hole into which the control spool is inserted,
   The control spool is
   a main body that is in sliding contact with the spool accommodation hole;
   a flange portion provided at an end portion of the main body portion and having an outer diameter larger than that of the main body portion;
   Further movement of the control spool along the urging force exerted by the auxiliary urging member is restricted by abutment of the flange portion against a stopper portion provided on the case in accordance with the movement of the control spool. is,
   A hydraulic rotating machine, wherein the urging force of the auxiliary urging member and the thrust due to the signal pressure act on the flange portion.
7. The hydraulic rotating machine according to any one of claims 1 to 4,
   A hydraulic rotating machine, wherein the signal pressure is generated by an electromagnetic proportional pressure reducing valve.

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