JP2021156200A - Pump control pressure regulator - Google Patents

Abstract

To prevent that horsepower control pressure having an unintended-magnitude is supplied to a pump from a pump control pressure regulator.SOLUTION: A regulator 50 comprises: a case main body 3a having a control pressure passage 11, a discharge pressure passage 10 and a signal pressure passage 13; a sleeve 60 attached to an installation hole 67 of the case main body 3a, and having a first port 60a, a second port 60b and a third port 60c; and a control spool 52 slidably accommodated in the sleeve 60, and displaced in an axial direction according to discharge pressure supplied through the second port 60b and signal pressure supplied through the third port 60c, and lower than the discharge pressure. A drain passage 63 is formed at the sleeve 60, and the drain passage 63 is opened between a second connection part 82 at which the discharge pressure passage 10 and the second port 60b are connected to each other, and a third connection part 83 at which the signal pressure passage 13 and the third port 60c are connected to each other.SELECTED DRAWING: Figure 2

Description

The present invention relates to a pump control pressure regulator.

Patent Document 1 discloses a pump control pressure regulator that supplies horsepower control pressure to a swash plate type piston pump whose drive horsepower is controlled according to horsepower control pressure. The horsepower control pressure supplied from the pump control pressure regulator to the swash plate type piston pump is changed according to the signal pressure supplied from the outside.

Japanese Unexamined Patent Publication No. 2008-240518

In the pump control pressure regulator described in Patent Document 1, a discharge pressure port into which the discharge pressure of the swash plate type piston pump is guided and a signal pressure port in which a signal pressure from the outside is guided are arranged adjacent to each other. When the discharge pressure port into which a relatively high pressure is guided and the signal pressure port in which a relatively low pressure is guided are arranged adjacent to each other, the discharge pressure port and the passage formed in the pump housing are arranged. Hydraulic oil may leak from the connection and flow into the signal pressure port. When hydraulic oil with a relatively high pressure flows into the signal pressure port, it will be in the same state as when the signal pressure is supplied even if the signal pressure is not supplied from the outside. The horsepower control pressure will be supplied from the pump control pressure regulator to the swash plate type piston pump.

When the magnitude of the horsepower control pressure supplied from the pump control pressure regulator to the swash plate type piston pump becomes an unintended magnitude, for example, the discharge amount of the swash plate type piston pump decreases and sufficient hydraulic oil is supplied to the hydraulic equipment. You may not be able to do it. Further, when the drive source for driving the swash plate type piston pump is an engine, the drive horsepower of the swash plate type piston pump increases, the engine becomes overloaded, and the engine may stop.

The present invention has been made in view of the above problems, and an object of the present invention is to prevent an unintended amount of horsepower control pressure from being supplied from the pump control pressure regulator to the pump.

In the present invention, a pump control pressure regulator that supplies a horsepower control pressure to a pump whose drive horsepower is controlled according to a horsepower control pressure guides a first passage that guides the horsepower control pressure to the pump, and a first passage that guides the discharge pressure of the pump. In a housing having two passages, a third passage through which a signal pressure lower than a discharge pressure that changes the horsepower of the pump is guided, and a mounting hole through which the first passage, the second passage, and the third passage are opened, and a mounting hole. A sleeve that is attached and has a first port that communicates with the first passage, a second port that communicates with the second passage, and a third port that communicates with the third passage, and is slidably housed in the sleeve. A control spool that is axially displaced according to the discharge pressure supplied through the second port and the signal pressure supplied through the third port to allow or cut off communication between the first port and the second port is provided. , The housing and the sleeve are provided with a drain passage communicating with the tank in which the working fluid is stored, and the drain passage includes a second connection portion connecting the second passage and the second port, and a third drain passage. It is characterized by opening between a third connection portion to which the passage and the third port are connected.

In the present invention, a drain passage communicating with the tank is opened between the second connection portion between the second passage and the second port and the third connection portion between the third passage and the third port. Therefore, even if the working fluid having a relatively high pressure leaks from the second connecting portion, the leaked working fluid flows into the drain passage without reaching the third connecting portion. As a result, when the signal pressure is not supplied to the pump control pressure regulator from the outside, it is possible to prevent the pump control pressure regulator from operating as if the signal pressure is being supplied. As a result, it is possible to prevent an unintended horsepower control pressure from being supplied from the pump control pressure regulator to the pump.

Further, the present invention is characterized in that one end of the drain passage is opened on the outer peripheral surface of the sleeve, and the other end is opened on the sliding surface between the sleeve and the control spool.

In the present invention, the drain passage is opened on the outer peripheral surface of the sleeve and on the sliding surface between the sleeve and the control spool. As a result, it is possible to prevent a relatively high pressure working fluid from flowing into the third port through the gap between the sleeve and the control spool as well as the gap between the sleeve and the housing. As a result, it is possible to prevent an unintended horsepower control pressure from being supplied from the pump control pressure regulator to the pump.

Further, in the present invention, a recovery chamber for collecting the working fluid leaked through the gap between the control spool and the sleeve and a recovery passage for collecting the working fluid collected in the recovery chamber to the tank are sleeves. The drain passage is connected to the collection passage.

In the present invention, the drain passage is connected to a recovery passage that collects the working fluid leaked through the gap between the control spool and the sleeve. By using the passage formed in the sleeve and communicating the drain passage with the tank in this way, it is not necessary to separately provide a communication passage connecting the drain passage and the tank. Therefore, it is possible to suppress an increase in manufacturing cost due to the provision of the drain passage.

According to the present invention, it is possible to prevent an unintended amount of horsepower control pressure from being supplied from the pump control pressure regulator to the pump.

It is sectional drawing of the swash plate type pump provided with the pump control pressure regulator which concerns on embodiment of this invention. It is sectional drawing along the line II-II in FIG. FIG. 5 is an enlarged cross-sectional view showing an enlarged cross section taken along the line III-III in FIG. 2. It is a figure which shows the modification of the swash plate type pump provided with the pump control pressure regulator which concerns on embodiment of this invention, and is the sectional view which shows the cross section corresponding to FIG.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

With reference to FIG. 1, a swash plate type pump 100 (hereinafter, referred to as “pump 100”) including a pump control pressure regulator 50 (hereinafter, referred to as “regulator 50”) according to an embodiment of the present invention will be described. The pump 100 is used as a hydraulic supply source for supplying hydraulic oil as a hydraulic fluid to a hydraulic device such as a hydraulic cylinder, and is rotationally driven by a drive source such as an engine.

As shown in FIG. 1, the pump 100 is a swash plate type piston pump, and has a shaft 1 as a drive shaft rotated by a power source, a cylinder block 2 connected to the shaft 1 and rotated together with the shaft 1, and a cylinder block 2. A case 3 for accommodating the above is provided.

The case 3 has a case main body 3a as a bottomed cylindrical housing and a cover 3b that seals an open end of the case main body 3a. The inside of the case 3 communicates with a tank (not shown) in which hydraulic oil is stored through a drain pipe (not shown). Therefore, the pressure inside the case 3 is almost equal to the tank pressure.

The cover 3b is formed with an insertion hole 3c through which the shaft 1 is inserted, and the shaft 1 is rotatably supported by the insertion hole 3c via the bearing 4a. A power source (not shown) such as an engine is connected to one end 1a of the shaft 1 protruding outward from the cover 3b. The other end 1b of the shaft 1 inserted into the case 3 is accommodated in a shaft accommodating hole 3d provided at the bottom of the case body 3a, and is rotatably supported by the shaft accommodating hole 3d via a bearing 4b. .. The other end 1b of the shaft 1 may be connected to the rotating shaft of another hydraulic pump such as a gear pump driven by a power source together with the pump 100.

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 columnar 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 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 the shoe 7 is in sliding contact with the rotation of the cylinder block 2, a cylinder block 2 and a case body. A valve plate 9 provided between the bottom of the 3a and the bottom of the 3a is further provided.

The shoe 7 has 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 pump 100 variable.

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. The valve plate 9 has a suction port (not shown) for connecting a suction passage (not shown) formed in the cylinder block 2 and a volume chamber 6, and a discharge passage and a volume chamber 6 (not shown) formed in the cylinder block 2. A discharge port (not shown) to be connected is formed.

Further, as shown in FIGS. 1 and 2, the pump 100 has a first urging mechanism 20 as an urging mechanism for urging the swash plate 8 in a direction in which the tilt angle becomes smaller, and the tilt angle becomes larger. A second urging mechanism 30 that urges the swash plate 8 in the direction, and a regulator 50 that supplies horsepower control pressure (hereinafter, referred to as “control pressure”) to the first urging mechanism 20 are further provided. Note that FIG. 2 is an enlarged cross-sectional view showing a part of the cross section taken along the line II-II of FIG. 1 in an enlarged manner.

As shown in FIG. 1, the first urging mechanism 20 includes a large-diameter piston 22 that is slidably inserted into the first piston accommodating hole 21 formed in the case body 3a and abuts on the swash plate 8, and a large-diameter piston. It has a control pressure chamber 23 partitioned by 22 in the first piston accommodating hole 21.

The control pressure adjusted by the regulator 50 is guided to the control pressure chamber 23. That is, the large-diameter piston 22 of the first urging mechanism 20 is displaced so as to change the tilt angle of the swash plate 8 according to the control pressure supplied from the regulator 50, and the tilt angle increases as the control pressure increases. The swash plate 8 is urged in the direction in which

As shown in FIG. 2, the second urging mechanism 30 is formed by a small-diameter piston 32 that is slidably inserted into the second piston accommodating hole 31 formed in the case body 3a and abuts on the swash plate 8 and a small-diameter piston 32. It has a pressure chamber 33 partitioned in the second piston accommodating hole 31. Although omitted in FIG. 2, the end of the small-diameter piston 32 opposite to the end facing the pressure chamber 33 is in contact with the swash plate 8.

The discharge pressure of the pump 100 is constantly guided to the pressure chamber 33 through the discharge pressure passage 10 formed in the case body 3a. The small-diameter piston 32 of the second urging mechanism 30 receives the discharge pressure guided to the pressure chamber 33 and is displaced so as to change the tilt angle of the swash plate 8. The higher the discharge pressure, the larger the tilt angle. The swash plate 8 is urged in the direction of

The large-diameter piston 22 has a larger outer diameter than the small-diameter piston 32, and receives the control pressure guided to the control pressure chamber 23. The pressure-receiving area of the large-diameter piston 22 receives the discharge pressure guided to the pressure chamber 33. It is larger than the pressure receiving area of the small diameter piston 32.

The regulator 50 mainly adjusts the control pressure guided to the control pressure chamber 23 according to the discharge pressure of the pump 100, and controls the output of the pump 100, that is, the horsepower required to drive the pump 100. Provided for.

The regulator 50 includes a feedback pin 40 that is displaced in the axial direction following the inclination of the swash plate 8, an urging member 51 that urges the feedback pin 40 toward the swash plate 8, and a discharge pressure and urging of the pump 100. A sleeve 60 provided with a control spool 52 for adjusting the control pressure by moving according to the urging force of the member 51 and a spool accommodating hole 65 for accommodating the control spool 52, and which is attached to the attachment hole 67 formed in the case body 3a. A plug 70 that seals one end of the spool accommodating hole 65 formed in the sleeve 60, and a columnar shaft member that is provided so that one end surface is in contact with the plug 70 and the other end is inserted into the control spool 52. 71 and.

The feedback pin 40 is a rod-shaped member, and is slidably inserted into a through hole 41 formed so as to penetrate the case body 3a in the axial direction. The feedback pin 40 is urged by the urging member 51 so that one end abuts on the swash plate 8.

The urging member 51 has an outer spring 51a and an inner spring 51b having a winding diameter smaller than that of the outer spring 51a and provided inside the outer spring 51a. The outer spring 51a and the inner spring 51b are coil springs, respectively, and are a first spring seat 72 that engages with the spherically formed end of the feedback pin 40 and a second spring seat 72 that engages with the end of the control spool 52. It is interposed between the spring seat 73 and.

The natural length (free length) of the outer spring 51a is set longer than the natural length of the inner spring 51b, and 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 set. , The inner spring 51b is in a compressed state between the first spring seat 72 and the second spring seat 73, while one end of the inner spring 51b is separated from the spring seat (first spring seat 72 in FIG. 1). It becomes a floating state, that is, a natural length state.

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 outer spring 51a is compressed to a state shorter than 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 of the outer spring 51a and the inner spring 51b acting on the swash plate 8 via the feedback pin 40 gradually increase as the tilt angle of the swash plate 8 decreases.

The mounting hole 67 to which the sleeve 60 is mounted is a through hole formed through the case body 3a in the axial direction so that one end opens with respect to the inside of the case 3, and is formed on the inner peripheral surface of the mounting hole 67. As shown in FIG. 2, a control pressure passage 11 as a first passage for guiding the control pressure to the control pressure chamber 23, a discharge pressure passage 10 as a second passage for guiding the discharge pressure of the pump 100, and a discharge pressure passage 10 supplied from the outside. A signal pressure passage 13 as a third passage through which the signal pressure to be performed is guided is open.

The sleeve 60 is a cylindrical member formed by axially penetrating a spool accommodating hole 65 into which the control spool 52 is inserted. As shown in FIG. 2, the spool accommodating hole 65 has a first hole portion 65a that slidably supports the control spool 52, and a second hole portion 65b having an inner diameter larger than that of the first hole portion 65a. The spool accommodating hole 65 is sealed by screwing the plug 70 into the second hole portion 65b.

Inside the second hole 65b whose open end is sealed by the plug 70, hydraulic oil leaked from the gap between the sleeve 60 and the control spool 52 and the gap between the control spool 52 and the shaft member 71. A collection room 66 is provided to collect the oil. Further, in order to return the hydraulic oil recovered in the recovery chamber 66 to the tank, a recovery passage 62 is formed in the sleeve 60. The recovery passage 62 is a plurality of through holes formed by penetrating along the axial direction of the sleeve 60 so that one end opens in the recovery chamber 66, and the other end opens with respect to the inside of the case 3. There is.

On the outer circumference of the sleeve 60, a first port 60a, a second port 60b, and a third port 60c are formed as annular grooves in this order from one end side facing the inside of the case 3. Further, in the sleeve 60, the first communication hole 61a, the second communication hole 61b, and the third communication hole 61c communicating with the first port 60a, the second port 60b, and the third port 60c, respectively, penetrate in the radial direction. Each is formed as a through hole. The first communication hole 61a, the second communication hole 61b, and the third communication hole 61c are opened on the inner peripheral surface of the first hole portion 65a, respectively.

With the sleeve 60 attached to the mounting hole 67, the first port 60a communicates with the control pressure passage 11 that guides the control pressure to the control pressure chamber 23, and the second port 60b always guides the discharge pressure of the pump 100. The third port 60c communicates with the signal pressure passage 13 so as to communicate with the discharge pressure passage 10 to be taken. The signal pressure guided to the signal pressure passage 13 is, for example, the flood pressure discharged from another pump driven by a power source together with the pump 100, and when this signal pressure is changed, a swash plate is used as described later. It is possible to change the drive horse power characteristic of the pump 100 by changing the tilt angle of 8 and changing the discharge amount of the pump 100.

As shown in FIG. 2, the control spool 52 has a main body portion 53 that is slidably supported by the first hole portion 65a of the spool accommodating hole 65, and is provided at one end of the main body portion 53 and has an outer diameter larger than that of the main body portion 53. It has a large flange portion 54 and a protruding portion 55 provided at an end portion opposite to the flange portion 54 and inserted into the second spring seat 73. The protruding portion 55 is formed to have an outer diameter smaller than that of the main body portion 53, and the second spring seat 73 abuts on the stepped surface 55a caused by the difference in outer diameter between the main body portion 53 and the protruding portion 55.

On the outer periphery of the main body 53, a first control port 56a, a second control port 56b, and a third control port 56c are formed as annular grooves in this order from the protruding portion 55 side. Further, the control spool 52 has a first control passage 57a, a second control passage 57b, and a third control passage 57c communicating with the first control port 56a, the second control port 56b, and the third control port 56c, respectively. Each is formed as a through hole penetrating in the radial direction.

Further, the control spool 52 is formed with an axial passage 58a having one end opened on the tip surface of the protrusion 55 and the other end connected to the first control passage 57a along the axial direction. The axial passage 58a is provided to communicate the first control passage 57a with the inside of the case 3 together with the connection passage 73a formed in the second spring seat 73. In other words, the first control passage 57a communicates with the inside of the case 3 through the axial passage 58a and the connecting passage 73a, and the pressure in the first control passage 57a is the same as the tank pressure.

Further, in the control spool 52, a first insertion hole 58b that opens at the end on the plug 70 side and a second insertion hole 58c that is continuously provided in the first insertion hole 58b are coaxially provided along the axial direction. Is formed in. The first insertion hole 58b has a length reaching the third control passage 57c in the axial direction, and the second insertion hole 58c has a length reaching the second control passage 57b in the axial direction. The inner diameter of the first insertion hole 58b is formed larger than the inner diameter of the second insertion hole 58c, and the first insertion hole 58b has a large diameter formed on the proximal end side of the shaft member 71 that abuts on the plug 70. The portion 71a is slidably inserted, and the small diameter portion 71b formed on the tip end side of the shaft member 71, which is smaller in diameter than the large diameter portion 71a, is slidably inserted into the second insertion hole 58c. The shaft member 71 to be inserted into the control spool 52 is formed of a member separate from the plug 70, but may be integrally formed with the plug 70.

As shown in FIG. 2, when the flange portion 54 of the control spool 52 is in contact with the plug 70, it is defined by the second insertion hole 58c and the end surface of the small diameter portion 71b inserted into the second insertion hole 58c. A second control passage 57b opens in the discharge pressure oil chamber 59a.

Since the second control passage 57b is constantly communicating with the discharge pressure passage 10 through the second control port 56b, the second communication hole 61b, and the second port 60b, the discharge pressure oil chamber 59a is always discharged from the pump 100. Pressure is guided. The discharge pressure introduced into the discharge pressure oil chamber 59a through the second control passage 57b acts to expand the discharge pressure oil chamber 59a, that is, to push out the small diameter portion 71b from the inside of the second insertion hole 58c. In other words, the control spool 52 is pressed by the pressure of the hydraulic oil guided to the discharge pressure oil chamber 59a in the axial direction away from the plug 70, that is, in the direction of compressing the outer spring 51a and the inner spring 51b.

Further, as shown in FIG. 2, in a state where the flange portion 54 of the control spool 52 is in contact with the plug 70, the stepped surface 71c formed by the outer diameter difference between the large diameter portion 71a and the small diameter portion 71b, and the first step surface 71c. A third control passage 57c is opened in the signal pressure oil chamber 59b defined by the insertion hole 58b and the outer peripheral surface of the small diameter portion 71b.

Since the third control passage 57c is constantly communicating with the signal pressure passage 13 through the third control port 56c, the third communication hole 61c, and the third port 60c, the signal pressure oil chamber 59b is always supplied from the outside. Signal pressure is derived. The signal pressure introduced into the signal pressure oil chamber 59b through the third control passage 57c acts to expand the signal pressure oil chamber 59b, that is, to push out the large diameter portion 71a from the inside of the first insertion hole 58b. .. In other words, the control spool 52 is pressed by the pressure of the hydraulic oil guided to the signal pressure oil chamber 59b in the axial direction away from the plug 70, that is, in the direction of compressing the outer spring 51a and the inner spring 51b.

In this way, the control spool 52 is urged away from the swash plate 8 by the urging force of the outer spring 51a and the inner spring 51b (to the left in FIG. 2), while the swash plate 8 is urged by the discharge pressure and the signal pressure. It is urged in the direction approaching (to the right in FIG. 2). That is, the control spool 52 has the urging force of the urging member 51 composed of the outer spring 51a and the inner spring 51b and the urging force of the pump 100 guided to the discharge pressure oil chamber 59a with respect to the sleeve 60. , The urging force due to the signal pressure guided to the signal pressure oil chamber 59b will move to a position where it is balanced.

Specifically, in the control spool 52, the flange portion 54 is in the first position where the flange portion 54 is in contact with the step portion 65c formed between the first hole portion 65a and the second hole portion 65b, and the flange portion 54 is the plug 70. It moves between the second position, which is in contact with the flange, and the two positions. note that. 1 and 2 show a state in which the control spool 52 is in the second position. The position of the control spool 52 is switched from the second position shown in FIGS. 1 and 2 to the first position by moving the control spool 52 to the right in the drawing.

In the first position, the first communication hole 61a and the second communication hole 61b of the sleeve 60 communicate with each other through the second control port 56b of the control spool 52, and communicate with the first control passage 57a and the first communication hole 61a of the control spool 52. Communication is cut off. Therefore, in the first position, the discharge pressure of the pump 100 is guided to the control pressure chamber 23 of the first urging mechanism 20 through the control pressure passage 11 communicating with the first communication hole 61a, and as a result, the swash plate The tilt angle of 8 becomes smaller and the discharge capacity of the pump 100 decreases.

On the other hand, in the second position, the first communication hole 61a and the first control passage 57a communicate with each other through the first control port 56a, and the communication between the first communication hole 61a and the second communication hole 61b is cut off. As described above, the first control passage 57a communicates with the inside of the case 3 through the axial passage 58a and the connecting passage 73a. Therefore, in the second position, the tank pressure is passed through the control pressure passage 11 to the control pressure chamber 23. As a result, the tilt angle of the swash plate 8 becomes large and the discharge capacity of the pump 100 increases.

When the position of the control spool 52 is switched between the first position and the second position, the first communication hole 61a of the sleeve 60 becomes the second communication hole 61b of the sleeve 60 and the first of the control spool 52. It is in a state of communicating with both the control passage 57a. In other words, in the regulator 50, when the position of the control spool 52 is switched between the first position and the second position, the first communication hole 61a is in a state of not communicating with any passage, and the first communication hole 61a is in a state of not communicating with any passage. It is configured so that the pressure is not confined in the 61a and the control pressure chamber 23.

Next, the operation of the pump 100 including the regulator 50 having the above configuration will be described.

The pump 100 is controlled by the regulator 50 so as to generate a constant horsepower characteristic in which the relationship between the discharge pressure and the discharge flow rate of the pump 100 is substantially inversely proportional, that is, a characteristic in which the product of the discharge pressure and the discharge flow rate is substantially constant. ..

The discharge pressure of the pump 100 increases, for example, as the load of the hydraulic cylinder driven by the discharge pressure of the pump 100 increases. When the discharge pressure of the pump 100 rises from the state where the tilt angle of the swash plate 8 is maintained at the maximum, the urging force of the pump 100 acting on the control spool 52 exceeds the urging force of the outer spring 51a and is controlled. The spool 52 moves from the second position to the first position.

When the control spool 52 moves to the first position, the discharge pressure is guided to the control pressure chamber 23 through the control pressure passage 11 as described above, so that the pressure in the control pressure chamber 23 rises. As the pressure in the control pressure chamber 23 rises, the large-diameter piston 22 is pushed out from the first piston accommodating hole 21 and tilts the swash plate 8 in a direction in which the tilt angle becomes smaller.

When the swash plate 8 is tilted in a direction in which the tilt angle becomes smaller, the feedback pin 40 moves to the left in FIG. 1 following the swash plate 8 so as to compress the outer spring 51a and the inner spring 51b. In other words, when the swash plate 8 tilts in a direction in which the tilt angle becomes smaller, the feedback pin 40 increases the urging force of the outer spring 51a and the inner spring 51b that urge the control spool 52 toward the second position. Move to.

The compression increases the urging force of the outer spring 51a and the inner spring 51b, and when the control spool 52 is pushed back by the urging force of the outer spring 51a and the inner spring 51b and moves to the second position, the control pressure chamber 23 controls. It communicates with the inside of the case 3 through the pressure passage 11. Therefore, the pressure in the control pressure chamber 23 gradually decreases.

When the pressure in the control pressure chamber 23 decreases, the large-diameter piston 22 is pushed back into the first piston accommodating hole 21 by the urging force of the outer spring 51a and the inner spring 51b acting via the swash plate 8. That is, when the pressure in the control pressure chamber 23 decreases, the swash plate 8 tilts in a direction in which the tilt angle increases, and the urging forces of the outer spring 51a and the inner spring 51b that urge the control spool 52 become smaller. As the urging force of the outer spring 51a and the inner spring 51b becomes smaller, the control spool 52 moves to the first position again due to the discharge pressure of the pump 100, and the swash plate 8 tends to have a smaller tilt angle again. It will be tilted.

The control spool 52 repeats such movements and stays at a position where the urging force due to the discharge pressure of the pump 100 acting on the control spool 52 and the urging force of the outer spring 51a and the inner spring 51b are balanced. Further, the swash plate 8 stays at a tilt angle in which the urging force of the large-diameter piston 22 and the urging force of the outer spring 51a and the inner spring 51b are balanced.

Since the pressure in the control pressure chamber 23 increases as the discharge pressure of the pump 100 increases, the tilt angle of the swash plate 8 also decreases as the discharge pressure of the pump 100 increases. As a result, the discharge capacity of the pump 100 decreases as the discharge pressure of the pump 100 increases.

On the other hand, when the load of the hydraulic cylinder driven by the discharge pressure of the pump 100 decreases, the discharge pressure of the pump 100 also decreases accordingly. When the discharge pressure of the pump 100 decreases, the urging force of the pump 100 acting on the control spool 52 falls below the urging force of the outer spring 51a and the inner spring 51b, and the control spool 52 moves from the first position to the second position. Move towards.

When the control spool 52 moves to the second position, the tank pressure is guided to the control pressure chamber 23 through the control pressure passage 11 as described above, so that the pressure in the control pressure chamber 23 decreases. When the pressure in the control pressure chamber 23 decreases, the large-diameter piston 22 is pushed back into the first piston accommodating hole 21 by the urging force of the outer spring 51a and the inner spring 51b acting via the swash plate 8. As a result, the swash plate 8 tilts in a direction in which the tilt angle increases.

When the swash plate 8 tilts in a direction in which the tilt angle increases, the feedback pin 40 is urged by the outer spring 51a and the inner spring 51b, particularly the outer spring 51a, and follows the swash plate 8 in the right direction in FIG. Move to. In other words, when the swash plate 8 tilts in the direction in which the tilt angle increases, the feedback pin 40 reduces the urging force of the outer spring 51a and the inner spring 51b that urge the control spool 52 toward the second position. To move.

When the urging force of the outer spring 51a and the inner spring 51b is reduced by the extension and the urging force of the outer spring 51a and the inner spring 51b acting on the control spool 52 is lower than the urging force of the discharge pressure of the pump 100, the control spool 52 Moves from the second position to the first position. When the control spool 52 compresses the outer spring 51a and the inner spring 51b and moves to the first position, the discharge pressure of the pump 100 is guided to the control pressure chamber 23 through the control pressure passage 11, so that the pressure in the control pressure chamber 23 is increased. Gradually rises. However, since the discharge pressure of the pump 100 is lowered, the degree of increase in the pressure in the control pressure chamber 23 is smaller than that in the case where the discharge pressure of the pump 100 is high.

When the pressure in the control pressure chamber 23 rises, the large-diameter piston 22 is pushed out from the first piston accommodating hole 21 and tilts the swash plate 8 in a direction in which the tilt angle becomes smaller. When the swash plate 8 tilts in the direction in which the tilt angle decreases in this way, the urging forces of the outer spring 51a and the inner spring 51b that urge the control spool 52 increase. As the urging force of the outer spring 51a and the inner spring 51b increases, the control spool 52 moves to the second position again, and the swash plate 8 tilts again in the direction in which the tilt angle increases.

The control spool 52 repeats such movements and stays at a position where the urging force due to the discharge pressure of the pump 100 acting on the control spool 52 and the urging force of the outer spring 51a and the inner spring 51b are balanced. Further, the swash plate 8 stays at a tilt angle in which the urging force of the large-diameter piston 22 and the urging force of the outer spring 51a and the inner spring 51b are balanced.

Since the pressure in the control pressure chamber 23 decreases as the discharge pressure of the pump 100 decreases, the tilt angle of the swash plate 8 increases as the discharge pressure of the pump 100 decreases. As a result, the discharge capacity of the pump 100 increases as the discharge pressure of the pump 100 decreases.

As described above, the discharge capacity of the pump 100 decreases as the discharge pressure of the pump 100 increases, and the discharge capacity of the pump 100 increases as the discharge pressure of the pump 100 decreases, that is, the pump 100. The pump 100 is controlled by the regulator 50 so that the relationship between the discharge pressure and the discharge capacity is substantially inversely proportional.

In addition to such constant horsepower control, when an auxiliary machine such as an air conditioner or a generator is driven by an engine (drive source) that drives the pump 100, the pump 100 is used to avoid stopping due to an overload. Horsepower reduction control is performed to reduce the driving horsepower of the engine.

Next, the horsepower control performed by the regulator 50 will be described.

When the auxiliary machine is driven by the engine, signal pressure is supplied to the signal pressure passage 13 from the outside. Specifically, the discharge pressure of a signal pressure generation pump (not shown), which is a signal pressure supply source, is guided as a signal pressure to the signal pressure passage 13 through a signal pressure control valve (not shown). The pressure in the signal pressure passage 13 is controlled by the signal pressure control valve according to the driving state of the auxiliary machine, and the auxiliary machine has a predetermined magnitude of the signal pressure while the auxiliary machine is being driven by the engine. Is controlled to be equivalent to the tank pressure while the is stopped.

When the auxiliary machine is driven and a signal pressure of a predetermined pressure is supplied to the signal pressure passage 13 through the signal pressure control valve, the supplied signal pressure becomes the third communication hole 61c and the third control port 56c as described above. And is guided to the signal pressure oil chamber 59b through the third control passage 57c. Then, the pressure guided to the signal pressure oil chamber 59b causes the control spool 52 to move away from the plug 70 in the axial direction, that is, the outer spring 51a, similarly to the discharge pressure of the pump 100 guided to the discharge pressure oil chamber 59a. And it becomes an urging force that presses the inner spring 51b in the direction of compression.

That is, while the auxiliary machine is being driven, the control spool 52 has an urging force due to the signal pressure guided to the signal pressure oil chamber 59b in addition to the urging force due to the discharge pressure of the pump 100 guided to the discharge pressure oil chamber 59a. Acts in the direction of moving the control spool 52 to the first position. Therefore, the control spool 52 operates in the same manner as when the discharge pressure of the pump 100 increases by a predetermined amount.

Therefore, while the auxiliary machine is being driven, the discharge capacity of the pump 100 is lower than when the auxiliary machine is stopped, that is, when the pressure in the signal pressure oil chamber 59b is equal to the tank pressure. do. By reducing the discharge capacity of the pump 100 when the auxiliary machine is being driven in this way, the driving horsepower of the pump 100 is reduced. As a result, the horsepower for driving the auxiliary machine is secured in the engine. It is possible to make it.

Here, it is assumed that the third port 60c to which the signal pressure is guided is provided adjacent to the second port 60b to which the discharge pressure of the pump 100 is constantly guided and the first port 60a to which the discharge pressure of the pump 100 is guided in a timely manner. , The relatively high pressure leaked from the first connection portion 81, which is the connection portion between the first port 60a and the control pressure passage 11, and the second connection portion 82, which is the connection portion between the second port 60b and the discharge pressure passage 10. The hydraulic oil may reach the third connection portion 83, which is the connection portion between the third port 60c and the signal pressure passage 13, and flow into the third port 60c.

When the hydraulic oil having a relatively high pressure flows into the third port 60c in this way, the pressure in the signal pressure oil chamber 59b becomes relatively high. Therefore, when the signal pressure is not supplied to the third port 60c, That is, even when the auxiliary machine is not driven, the signal pressure is supplied to the third port 60c, that is, the same state as when the auxiliary machine is driven. Therefore, the pump 100 is continuously or intermittently supplied with an unintended control pressure that reduces the discharge capacity from the regulator 50 through the control pressure passage 11. As a result, the discharge capacity of the pump 100 may unintentionally decrease or fluctuate, and the operation of the hydraulic equipment to which the hydraulic oil is supplied may become unstable.

In order to avoid such a situation, in the present embodiment, the first connection portion 81 between the first port 60a and the control pressure passage 11 and the second connection portion 82 between the second port 60b and the discharge pressure passage 10 are used. Comparison of leaks from the first connection portion 81 and the second connection portion 82 by opening the drain passage 63 communicating with the tank between the third port 60c and the third connection portion 83 of the signal pressure passage 13. It suppresses the high pressure hydraulic oil from reaching the third connection portion 83.

Hereinafter, the drain passage 63 will be described with reference to FIGS. 2 and 3. Note that FIG. 3 is an enlarged cross-sectional view taken along the line III-III of FIG.

The drain passage 63 has a fourth port 60d formed as an annular groove on the outer circumference of the sleeve 60 and a fourth communication hole 61d as a through hole formed through the sleeve 60 in the radial direction and communicating with the fourth port 60d. A fourth control port 56d formed as an annular groove on the outer periphery of the main body 53 of the control spool 52 and always communicating with the communication hole 61d.

As shown in FIG. 2, the fourth port 60d is arranged between the second port 60b and the third port 60c, and the fourth control port 56d is between the second control port 56b and the third control port 56c. Placed in. As described above, one end of the drain passage 63 is open on the outer peripheral surface of the sleeve 60, and the other end is open on the sliding surface between the sleeve 60 and the control spool 52.

The fourth communication hole 61d that communicates the fourth port 60d and the fourth control port 56d is connected to a recovery passage 62 formed through the sleeve 60 in the axial direction, as shown in FIG. .. As shown in FIG. 3, the recovery passage 62 is for avoiding communication with the first communication hole 61a, the second communication hole 61b, and the third communication hole 61c formed by penetrating the sleeve 60 in the radial direction. The communication holes 61a, 61b, 61c are provided at a certain interval in the circumferential direction.

The direction of forming the fourth communication hole 61d is not limited to the radial direction of the sleeve 60, and what if the fourth port 60d and the fourth control port 56d communicate with each other and are connected to the recovery passage 62? It may be formed in. The fourth communication hole 61d and the recovery passage 62 are not formed on the same cross section of the communication holes 61a, 61b, 61c and the sleeve 60, but in FIG. 2, the fourth communication hole 61d and the recovery passage 62 are formed. The fourth communication hole 61d and the recovery passage 62 are shown by broken lines so that the positional relationship between the communication holes 61a, 61b, and 61c can be easily understood.

Since the collection passage 62 is open to the inside of the case 3 as described above, the drain passage 63 communicates with the inside of the case 3 communicating with the tank through the collection passage 62, and is a drain passage. The pressure of 63 is the same as the tank pressure.

Therefore, the first connection portion 81 between the first port 60a and the control pressure passage 11, the second connection portion 82 between the second port 60b and the discharge pressure passage 10, and the third of the third port 60c and the signal pressure passage 13. By opening the drain passage 63 that connects to the recovery passage 62 between the connection portion 83 and the connection portion 83, the relatively high-pressure hydraulic oil leaked from the first connection portion 81 and the second connection portion 82 is brought into the third connection. It will be guided to the tank through the drain passage 63 and the recovery passage 62 without reaching the portion 83.

By preventing the relatively high-pressure hydraulic oil leaking from the first connection portion 81 and the second connection portion 82 from flowing into the third port 60c in this way, the signal pressure is supplied to the regulator 50 from the outside. When not, it is avoided that the regulator 50 operates as if signal pressure is being supplied, and as a result, unintended control pressure is continuously or intermittently supplied from the regulator 50 to the pump 100. Can be prevented. Further, by stabilizing the control pressure supplied from the regulator 50 to the pump 100, the discharge capacity and the driving horsepower of the pump 100 are stabilized, and the hydraulic equipment to which the hydraulic oil is supplied from the pump 100 is operated and the pump 100 is driven. The operation of the drive source such as the engine is also stable.

Further, the drain passage 63 is formed so as to penetrate the sleeve 60 in the radial direction, and is also open on the sliding surface between the sleeve 60 and the control spool 52. Therefore, through the sliding surface between the sleeve 60 and the control spool 52, such as the connection portion between the second control port 56b and the first communication hole 61a and the connection portion between the second control port 56b and the second communication hole 61b. Even if a relatively high-pressure hydraulic oil leaks from the connecting portion, the leaked hydraulic oil does not reach the connecting portion between the third control port 56c and the third communication hole 61c, and the drain passage 63 (the first). 4 It is guided to the tank through the control port 56d, the fourth communication hole 61d) and the recovery passage 62.

By opening the drain passage 63 also on the inner peripheral surface of the first hole portion 65a of the sleeve 60 in this way, not only the gap between the sleeve 60 and the case body 3a but also the sleeve 60 and the control spool 52 It is possible to prevent a relatively high pressure hydraulic oil from flowing into the signal pressure oil chamber 59b, the third communication hole 61c, and the third control port 56c through the gap between the two. As a result, it is possible to more reliably prevent unintended control pressure from being supplied from the regulator 50 to the pump 100 continuously or intermittently.

Further, the drain passage 63 communicates with the tank through a collection passage 62 provided in the sleeve 60 for communicating the collection chamber 66 with the inside of the case 3. In this way, by using the passage formed in advance in the sleeve 60 like the collection passage 62 and communicating the drain passage 63 with the tank, it is not necessary to separately provide a communication passage for communicating the drain passage 63 and the tank. .. Therefore, it is possible to suppress an increase in manufacturing cost due to the addition of the drain passage 63.

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

In the regulator 50 having the above configuration, the first connection portion 81 between the first port 60a and the control pressure passage 11, the second connection portion 82 between the second port 60b and the discharge pressure passage 10, the third port 60c and the signal pressure passage A drain passage 63 communicating with the tank is opened between the third connecting portion 83 and the third connecting portion 83. Therefore, even if the hydraulic oil having a relatively high pressure leaks from the first connection portion 81 or the second connection portion 82, the leaked hydraulic oil flows into the drain passage 63 without reaching the third connection portion 83. It will be.

As a result, when the signal pressure is not supplied to the regulator 50 from the outside, the regulator 50 is prevented from operating as if the signal pressure is being supplied. As a result, it is possible to prevent an unintended control pressure from being continuously or intermittently supplied from the regulator 50 to the pump 100. Further, by stabilizing the control pressure supplied from the regulator 50 to the pump 100, the discharge capacity and the driving horsepower of the pump 100 are stabilized, and as a result, the operation of the hydraulic equipment to which the hydraulic oil is supplied and the pump 100 are driven. It is possible to stabilize the operation of a drive source such as an engine.

The following modifications are also within the scope of the present invention, and the configurations shown in the modifications and the configurations described in the above-described embodiments may be combined, or the configurations described in the following different modifications may be combined. Is also possible.

In the above embodiment, the pump 100 to which the control pressure is supplied from the regulator 50 is a swash plate type piston pump. The type of the pump 100 is not limited to this, and any type of pump may be used as long as the capacity is changed by supplying the control pressure from the regulator 50 to the mechanism for changing the capacity. For example, it may be a variable displacement vane pump.

Further, in the above embodiment, the drain passage 63 is provided in the sleeve 60. Instead of this, the drain passage may be provided in the case body 3a. In this case, the drain passage is formed so as to open on the inner peripheral surface of the mounting hole 67 between the discharge pressure passage 10 and the signal pressure passage 13. In this case as well, even if the hydraulic oil having a relatively high pressure leaks from the first connection portion 81 or the second connection portion 82 as in the above embodiment, the leaked hydraulic oil reaches the third connection portion 83. Instead, it will flow into the drain passage provided in the case body 3a. In order to guide the leaked hydraulic oil to the drain passage, it is preferable to provide an annular groove communicating with the drain passage on the outer peripheral surface of the sleeve 60 or the inner peripheral surface of the mounting hole 67.

Further, in the above embodiment, the drain passage 63 is connected to the recovery passage 62 formed in the sleeve 60. Instead of this, a communication passage that communicates the drain passage 63 with the inside of the tank or the case 3 may be separately provided in, for example, the case main body 3a. In this case, the communication passage is formed so as to open on the inner peripheral surface of the mounting hole 67 formed in the case body 3a and communicate with the fourth port 60d.

Further, in the above embodiment, the signal pressure supplied to the signal pressure passage 13 is either a predetermined pressure signal pressure or a tank pressure. Alternatively, the signal pressure may be a pressure whose magnitude changes stepwise or steplessly between the signal pressure of a predetermined pressure and the tank pressure. In this case, the discharge capacity of the pump 100 can be changed to an arbitrary size, and the driving horsepower of the pump 100 can be changed to an arbitrary size. By making it possible to appropriately change the drive load of the pump 100 in this way, for example, the engine that drives the pump 100 can be operated with efficient rotation and load.

Further, in the above embodiment, the regulator 50 controls the horsepower reduction, and the signal pressure is supplied only when the auxiliary machine is driven by the engine. Instead of this, for example, in normal times, a signal pressure of a predetermined pressure is supplied to the signal pressure passage 13 to reduce the driving power of the pump 100, and the hydraulic oil required when there is a margin in the output of the engine or in the flood control equipment. By communicating the signal pressure passage 13 to the tank when the flow rate of the pump 100 is increased, the discharge capacity of the pump 100 is increased and the driving power of the pump 100 is increased when a predetermined condition is satisfied. May be good. As described above, the regulator 50 may be used for controlling horsepower instead of controlling horsepower.

Further, in the above embodiment, the signal pressure supplied to the regulator 50 causes the control spool 52 to move away from the plug 70 in the axial direction, that is, the outer spring 51a and the inner spring 51b, similarly to the discharge pressure of the pump 100. It is an urging force that presses in the direction of compression. Instead, as in the modified example shown in FIG. 4, the signal pressure supplied to the regulator 150 may be an urging force that presses the control spool 52 in the direction opposite to the discharge pressure of the pump 100. ..

In the modified example shown in FIG. 4, the sleeve 60 is provided between the first hole portion 65a and the second hole portion 65b, and has a larger inner diameter than the first hole portion 65a and a smaller inner diameter than the second hole portion 65b. The control spool 52 has a third hole portion 65d, and the control spool 52 has a second main body portion 53a provided between the main body portion 53 and the flange portion 54 and slidably supported by the third hole portion 65d.

Then, in this modification, the signal pressure oil chamber 59c from which the signal pressure is guided is a connecting surface that connects the first hole portion 65a, the third hole portion 65d, the first hole portion 65a, and the third hole portion 65d. The third control port 56c, the first stepped surface 53b formed by the outer diameter difference between the third control port 56c and the second main body 53a, and the outer diameter difference between the third control port 56c and the main body 53. It is defined by a second stepped surface 53c formed by the above.

The signal pressure guided through the signal pressure passage 13 and the third communication hole 61c in the signal pressure oil chamber 59c defined in this way acts on the first step surface 53b and the second step surface 53c facing each other in the axial direction. Will be done. Here, since the outer diameter of the second main body 53a is larger than the outer diameter of the main body 53, the first stepped surface 53b formed by the difference in outer diameter between the third control port 56c and the second main body 53a. The area is naturally larger than the area of the second stepped surface 53c formed by the difference in outer diameter between the third control port 56c and the main body 53.

Since there is a difference between the area of the first step surface 53b and the area of the second step surface 53c in this way, the signal pressure guided into the signal pressure oil chamber 59c presses the first step surface 53b having a large area. That is, it acts to push out the second main body portion 53a from the inside of the third hole portion 65d. In other words, the control spool 52 is pressed by the pressure of the hydraulic oil guided to the signal pressure oil chamber 59c in the axial direction toward the plug 70, that is, in the direction in which the outer spring 51a and the inner spring 51b are extended. ..

As described above, in the modified example shown in FIG. 4, the signal pressure guided to the signal pressure oil chamber 59c is an urging force that presses the control spool 52 in the direction opposite to the discharge pressure of the pump 100, unlike the above embodiment. ing. Therefore, when a signal pressure of a predetermined pressure is guided to the signal pressure oil chamber 59c, the control spool 52 operates in the same manner as when the discharge pressure of the pump 100 drops by a predetermined magnitude. That is, when a signal pressure of a predetermined pressure is guided to the signal pressure oil chamber 59c, the discharge capacity of the pump 100 increases, and the driving horsepower of the pump 100 increases.

Therefore, in this modification, as in the above embodiment, when the horsepower reduction control is performed by the regulator 150, the pressure in the signal pressure passage 13 is equal to the tank pressure while the auxiliary machine is driven by the engine. While the auxiliary machine is stopped, the signal pressure is controlled by the signal pressure control valve so that the signal pressure has a predetermined magnitude.

As a result, while the auxiliary machine is being driven, the discharge capacity of the pump 100 is lower than when the auxiliary machine is stopped. By reducing the discharge capacity of the pump 100 when the auxiliary machine is being driven in this way, the driving horsepower of the pump 100 is reduced. As a result, the horsepower for driving the auxiliary machine is secured in the engine. It is possible to make it.

Further, also in this modification, the drain passage 63 is open between the first connection portion 81 and the second connection portion 82 and the third connection portion 83, and the first connection portion 81 and the second connection portion 81 and the second connection portion are also opened. Since the relatively high pressure hydraulic oil leaked from 82 is suppressed from flowing into the third port 60c, an unintended control pressure that increases the discharge capacity from the regulator 150 to the pump 100 is continuously or intermittently applied. It can be prevented from being supplied to. As a result, as in the above embodiment, the discharge capacity of the pump 100 is stable, and the operation of the hydraulic equipment to which the hydraulic oil is supplied is also stable.

In this modified example, even if a signal pressure of a predetermined magnitude is not supplied to the signal pressure passage 13 due to a failure of the signal pressure control valve or the like and the pressure in the signal pressure passage 13 becomes equal to the tank pressure, the pump Since the driving horsepower of 100 is reduced, it is possible to prevent the engine load from becoming overloaded even when the signal pressure is not supplied due to a failure or the like.

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

The regulators 50 and 150 that supply the control pressure to the pump 100 include a control pressure passage 11 that guides the control pressure to the pump 100, a discharge pressure passage 10 that guides the discharge pressure of the pump 100, and a discharge pressure that changes the horsepower of the pump 100. A case body 3a having a signal pressure passage 13 to which a lower signal pressure is guided, a control pressure passage 11, a discharge pressure passage 10, and a mounting hole 67 through which the signal pressure passage 13 opens, and a mounting hole 67 are mounted and controlled. A sleeve 60 having a first port 60a communicating with the pressure passage 11, a second port 60b communicating with the discharge pressure passage 10, and a third port 60c communicating with the signal pressure passage 13 and slidable on the sleeve 60. The discharge pressure supplied through the second port 60b and the signal pressure supplied through the third port 60c are displaced in the axial direction to allow communication between the first port 60a and the second port 60b. A control spool 52 for shutting off is provided, and one of the case body 3a and the sleeve 60 is provided with a drain passage 63 communicating with a tank in which hydraulic oil is stored, and the drain passage 63 includes a discharge pressure passage 10 and a first. An opening is made between the second connecting portion 82 to which the two ports 60b are connected and the third connecting portion 83 to which the signal pressure passage 13 and the third port 60c are connected.

In this configuration, a drain passage communicating with the tank is provided between the second connection portion 82 between the second port 60b and the discharge pressure passage 10 and the third connection portion 83 between the third port 60c and the signal pressure passage 13. 63 is open. Therefore, even if the hydraulic oil having a relatively high pressure leaks from the second connecting portion 82, the leaked hydraulic oil will flow into the drain passage 63 without reaching the third connecting portion 83. As a result, when the signal pressure is not supplied to the regulators 50 and 150 from the outside, the regulators 50 and 150 are prevented from operating as if the signal pressure is being supplied. As a result, it is possible to prevent an unintended control pressure from being continuously or intermittently supplied from the regulators 50 and 150 to the pump 100. Further, by stabilizing the control pressure supplied from the regulators 50 and 150 to the pump 100, the discharge capacity and the driving horsepower of the pump 100 are stabilized, and as a result, the operation of the hydraulic equipment to which the hydraulic oil is supplied and the pump 100 are operated. It is possible to stabilize the operation of a drive source such as an engine that drives the engine.

Further, one end of the drain passage 63 is opened on the outer peripheral surface of the sleeve 60, and the other end is opened on the sliding surface between the sleeve 60 and the control spool 52.

In this configuration, the drain passage 63 is open not only on the outer peripheral surface of the sleeve 60 but also on the sliding surface between the sleeve 60 and the control spool 52. As a result, it is possible to prevent a relatively high pressure hydraulic oil from flowing into the third port 60c not only through the gap between the sleeve 60 and the case body 3a but also through the gap between the sleeve 60 and the control spool 52. Will be done. As a result, it is possible to more reliably prevent the unintended control pressure from being continuously or intermittently supplied from the regulators 50 and 150 to the pump 100.

Further, the sleeve 60 has a recovery chamber 66 for collecting the hydraulic oil leaked through the gap between the control spool 52 and the sleeve 60, and a recovery chamber 66 for collecting the hydraulic oil collected in the recovery chamber 66 into a tank. A passage 62 and a passage 62 are provided, and the drain passage 63 is connected to the collection passage 62.

In this configuration, the drain passage 63 is connected to a recovery passage 62 that collects the hydraulic oil leaked through the gap between the control spool 52 and the sleeve 60. In this way, by using the passage formed in advance in the sleeve 60 like the collection passage 62 and communicating the drain passage 63 with the tank, it is not necessary to separately provide a communication passage for communicating the drain passage 63 and the tank. .. Therefore, it is possible to suppress an increase in manufacturing cost due to the provision of the drain passage 63.

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 configurations of the above embodiments. No.

100 ... Swash plate type pump (pump), 50, 150 ... Pump control pressure regulator (regulator), 1 ... Shaft (drive shaft), 2 ... Cylinder block, 2b ... Cylinder, 3 ...・ ・ Case, 3a ・ ・ ・ Case body (housing), 5 ・ ・ ・ Piston, 6 ・ ・ ・ Volume chamber, 8 ・ ・ ・ Swash plate, 10 ・ ・ ・ Discharge pressure passage (2nd passage), 11 ・ ・・ Control pressure passage (1st passage), 13 ... Signal pressure passage (3rd passage), 20 ... 1st urging mechanism (biasing mechanism), 52 ... Control spool, 60 ... Sleeve , 60a ... 1st port, 60b ... 2nd port, 60c ... 3rd port, 60d ... 4th port, 62 ... Recovery passage, 63 ... Drain passage, 65 ... -Spool storage hole, 66 ... Recovery chamber, 67 ... Mounting hole, 81 ... 1st connection, 82 ... 2nd connection, 83 ... 3rd connection

Claims (3)

A pump control pressure regulator that supplies the horsepower control pressure to a pump whose drive horsepower is controlled according to the horsepower control pressure.
A first passage for guiding the horsepower control pressure to the pump, a second passage for guiding the discharge pressure of the pump, a third passage for guiding a signal pressure lower than the discharge pressure for changing the horsepower of the pump, and the above. A housing having a first passage, a mounting hole through which the second passage and the third passage open, and a housing.
A sleeve that is attached to the mounting hole and has a first port that communicates with the first passage, a second port that communicates with the second passage, and a third port that communicates with the third passage.
It is slidably housed in the sleeve and is displaced in the axial direction according to the discharge pressure supplied through the second port and the signal pressure supplied through the third port, and the first port and the first port are displaced. It is equipped with a control spool that allows or cuts off communication with two ports.
Either the housing or the sleeve is provided with a drain passage that communicates with the tank in which the working fluid is stored.
The drain passage opens between a second connection portion where the second passage and the second port are connected and a third connection portion where the third passage and the third port are connected. A pump control pressure regulator characterized by that. The pump control pressure regulator according to claim 1, wherein one end of the drain passage is opened on the outer peripheral surface of the sleeve, and the other end is opened on the sliding surface between the sleeve and the control spool. The sleeve has a recovery chamber for collecting the working fluid leaked through the gap between the control spool and the sleeve, and a recovery passage for collecting the working fluid collected in the recovery chamber to the tank. , Is provided,
The pump control pressure regulator according to claim 1 or 2, wherein the drain passage is connected to the recovery passage.

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