JP7112280B2 - Pumping unit - Google Patents

Description

The present invention relates to a pump unit.

Patent Document 1 discloses a pump that is housed in a tank and discharges the working fluid in the tank, a relief valve that opens according to the pressure of the working fluid discharged from the pump, and a flow of the working fluid discharged from the pump. A pump unit is disclosed that includes a valve block that defines a passageway and closes the open end of the tank. A motor for driving the pump is assembled to this pump unit via a valve block.

JP-A-10-82377

In the pump unit described in Patent Document 1, the thickness of the valve block in the axial direction of the rotating shaft of the pump is set according to the arrangement of the flow path formed in the valve block and the relief valve connected to the flow path. and the thickness of the valve block between the mounting surface of the motor and the mounting surface of the pump is the same thickness as the thickness of the valve block between the mounting surface of the motor and the mounting surface of the relief valve.

Therefore, as the thickness of the valve block increases, the length of the shaft connecting the pump and the motor also increases. If the length of the shaft connecting the pump and the motor increases, the shaft tends to become eccentric during high-speed rotation and high load, and eccentricity of the shaft may damage oil seals and bearings. Such a situation can be avoided by restricting the permissible operating range of the pump unit, but limiting the permissible operating range of the pump unit will degrade the discharge performance of the pump unit.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is an object of the present invention to expand the allowable operating range of the pump unit and improve the discharge performance of the pump unit.

The present invention comprises a pump unit comprising: a tank for storing a working fluid; a pump disposed in the tank and capable of discharging the working fluid in the tank by rotating a rotating shaft thereof by a driving source; and a driving source and the pump. A valve block to which the tank is assembled, an actuator passage formed in the valve block that connects the pump and the fluid pressure actuator and through which the working fluid discharged from the pump flows, and a fluid pressure actuator that is formed in the valve block and communicates the tank. a discharge passage that guides the working fluid discharged from the hydraulic actuator to a tank; a relief passage that is formed in the valve block and branches from the actuator passage and communicates with the tank; A relief valve that opens when the pressure of the working fluid reaches a predetermined pressure, a check valve that is provided in the actuator flow path and prevents the working fluid in the actuator flow path from flowing back to the pump side, and a discharge a discharge valve capable of discharging the working fluid in the flow path to the tank , the valve block having a first end face facing the inside of the tank, the first end face having a positioning position of the pump in the axial direction of the rotating shaft. A first assembly surface for carrying out the operation and a second assembly surface on which the relief valve is assembled are formed. The portion of the valve block on which the second assembly surface is formed is thinner than the thickness in the axial direction of the rotating shaft, and the check valve and the discharge valve are positioned so as not to overlap the pump when viewed in the axial direction of the rotating shaft. It is characterized by being arranged .

In the present invention, the thickness of the valve block on the first mounting surface for positioning the pump is formed thinner than the thickness of the valve block on the second mounting surface on which the relief valve is mounted. Therefore, the length of the shaft connecting the pump and the drive source can be shortened regardless of the presence or absence of the flow path formed in the valve block and the valve device connected to the flow path. In this way, by shortening the length of the shaft that connects the pump and the drive source, eccentricity of the shaft is suppressed during high-speed rotation and high load, and damage to bearings and oil seals is prevented. be able to. Also, in the present invention, the check valve and the discharge valve are arranged at positions that do not overlap with the pump when viewed in the axial direction of the rotating shaft. In this way, by not arranging the check valve or the discharge valve at a position overlapping the pump when viewed in the axial direction of the rotating shaft, it is possible to further reduce the thickness of the valve block on the first mounting surface.

The present invention is characterized in that the relief valve is arranged at a position at least partially overlapping with either one of the check valve and the discharge valve when viewed from the axial direction of the rotating shaft.

In this aspect of the invention, the relief valve is arranged so that at least a portion thereof overlaps with either one of the check valve and the discharge valve when viewed from the axial direction of the rotating shaft. By arranging the relief valve so as to overlap with the check valve and the discharge valve in this way, the pump unit can be made more compact than when they are arranged so that they do not overlap when viewed from the axial direction of the rotating shaft. be able to.

In the present invention, the pump unit further includes a filter provided in the discharge passage through which the working fluid discharged through the discharge valve flows, and the first end surface is formed with a third mounting surface to which the filter is mounted. The thickness in the axial direction of the rotating shaft of the valve block in the portion where the mounting surface is formed is the same as the thickness in the axial direction of the rotating shaft of the valve block in the portion where the second mounting surface is formed. characterized by

In the present invention, the thickness in the axial direction of the rotary shaft of the valve block at the portion where the third mounting surface is formed is the same as the thickness in the axial direction of the rotary shaft of the valve block at the portion where the second mounting surface is formed. formed to the same thickness. By arranging the second mounting surface on which the relief valve is mounted and the third mounting surface on which the filter is mounted on the same plane in this way, the shape of the valve block is simplified. manufacturing costs can be reduced.

The present invention is a swash plate type piston pump having a piston and a swash plate for reciprocating the piston, the rotary shaft having a connection portion connected to a drive source, and the connection portion connecting the piston to the drive source. The swash plate is provided on the opposite side of the swash plate.

In this invention, the connecting portion of the rotating shaft of the swash plate type piston pump connected to the drive source is provided on the opposite side of the swash plate with the piston interposed therebetween. That is, the piston is arranged between the valve block and the swash plate. Therefore, it is possible to easily form a passage for guiding the working fluid discharged from the pump toward the valve block. It becomes possible to easily connect the formed passages. As a result, the manufacturing cost of the pump unit can be reduced.

ADVANTAGE OF THE INVENTION According to this invention, the operation allowable range of a pump unit can be expanded and the discharge performance of a pump unit can be improved.

FIG. 1 is a hydraulic circuit of a cylinder control device to which a pump unit according to an embodiment of the invention is applied. FIG. 2 is a cross-sectional view of a pump unit according to an embodiment of the invention. FIG. 3 is a cross-sectional view taken along line III--III in FIG. FIG. 4 is a cross-sectional view along line VI-VI of FIG. FIG. 5 is a cross-sectional view along line VV in FIG. FIG. 6 is a cross-sectional view of a modification of the pump unit according to the embodiment of the invention.

A pump unit 100 according to an embodiment of the present invention will be described below with reference to the drawings.

A pump unit 100 is applied to a cylinder control device 1 that controls driving of a hydraulic cylinder 10 as a fluid pressure actuator. First, referring to FIG. 1, the hydraulic circuit of the cylinder control device 1 will be described. The pump unit 100 is the range surrounded by the dotted line in FIG.

The cylinder control device 1 includes a hydraulic cylinder 10 that expands and contracts depending on the supplied hydraulic oil (working fluid), a pump unit 100 that can supply hydraulic oil to the hydraulic cylinder 10, and a pump 30 of the pump unit 100 as a drive source. and an electric motor 20 of

The hydraulic cylinder 10 includes a cylinder tube 11, a piston 12 slidably inserted into the cylinder tube 11 and partitioning the inside of the cylinder tube 11 into a piston-side chamber 11a and a rod-side chamber 11b, and one end connected to the piston 12 and the other end. is a single-rod cylinder having a piston rod 13 projecting to the outside of the cylinder tube 11 . Note that the hydraulic cylinder 10 is not limited to a single-rod cylinder, and may be a double-rod cylinder. Further, the actuator to which hydraulic oil is supplied is not limited to the hydraulic cylinder 10, and may be any type of actuator as long as it is driven by hydraulic oil. For example, a hydraulic motor may be used. .

The pump unit 100 includes a pump 30 that is coupled to an electric motor 20 and rotates as the electric motor 20 rotates, and a tank 50 that stores hydraulic oil.

When the pump 30 is driven in the forward direction R1 by the electric motor 20, the pump 30 sucks hydraulic fluid from the second pump port 30b, discharges hydraulic fluid from the first pump port 30a, and is driven in the reverse direction R2 by the electric motor 20. When driven, hydraulic fluid is sucked from the first pump port 30a and hydraulic fluid is discharged from the second pump port 30b. Thus, the discharge direction of the pump 30 is switched according to the rotation direction of the electric motor 20 . A specific configuration of the pump 30 will be described later.

Further, the pump unit 100 includes a first passage 61 as an actuator passage connecting the piston side chamber 11 a of the hydraulic cylinder 10 and the first pump port 30 a of the pump 30 , a rod side chamber 11 b of the hydraulic cylinder 10 and the first passage 61 of the pump 30 . A second passage 62 as an actuator flow path connecting the two pump ports 30b, and first and second check valves 71 and 72 provided in the first and second passages 61 and 62, respectively.

The first check valve 71 only allows the hydraulic fluid to flow from the first pump port 30a to the piston-side chamber 11a of the hydraulic cylinder 10 through the first passage 61, and operates from the piston-side chamber 11a to the first pump port 30a. It is a check valve that blocks the flow of oil.

The second check valve 72 allows only the hydraulic fluid to flow from the second pump port 30b to the rod-side chamber 11b of the hydraulic cylinder 10 through the second passage 62, and operates from the rod-side chamber 11b to the second pump port 30b. It is a check valve that blocks the flow of oil.

The pump unit 100 also includes a first intake passage 63 connecting the second passage 62 and the tank 50 upstream of the second check valve 72 and a first passage 61 upstream of the first check valve 71 . It has a second intake passage 64 connecting to the tank 50, and first and second intake check valves 73, 74 provided in the first and second intake passages 63, 64, respectively.

The first intake check valve 73 allows hydraulic fluid to flow only from the tank 50 to the second pump port 30b, and the second intake check valve 74 permits hydraulic fluid to flow only from the tank 50 to the first pump port 30a. allow.

When hydraulic fluid is sucked from the second pump port 30b and hydraulic fluid is discharged from the first pump port 30a, the first intake check valve 73 is opened while the second intake check valve 74 is closed. When hydraulic fluid is sucked from the pump port 30a and hydraulic fluid is discharged from the second pump port 30b, the second intake check valve 74 opens and the first intake check valve 73 closes. When the electric motor 20 is stopped and hydraulic oil is not sucked from any of the pump ports 30a and 30b, the first intake check valve 73 and the second intake check valve 74 are closed, and the first passage 61 and The pressure in each of the second passages 62 is maintained.

In addition, the pump unit 100 includes a first discharge passage 65 as a discharge passage branching from the first passage 61 downstream of the first check valve 71 and connecting the first passage 61 and the tank 50, and a second check valve 71. A second discharge passage 66 as a discharge passage branching from the second passage 62 on the downstream side of the stop valve 72 and connecting the second passage 62 and the tank 50, and the first and second discharge passages 65, 66 are provided respectively. It has first and second pilot check valves 75 and 76 as discharge valves.

The first pilot check valve 75 is opened by the pressure of the hydraulic fluid discharged from the second pump port 30b, and by connecting the first passage 61 on the downstream side of the first check valve 71 and the tank 50, It is a so-called discharge valve that discharges the hydraulic oil in the piston-side chamber 11 a to the tank 50 . Further, the first pilot check valve 75 blocks the communication between the first passage 61 and the tank 50 when hydraulic oil is not discharged from the second pump port 30b, and the first pilot check valve 75 on the downstream side of the first check valve 71 blocks communication. It also functions as a pressure holding valve that holds the pressure in the first passage 61, that is, the pressure of the hydraulic oil in the piston-side chamber 11a.

The second pilot check valve 76 is opened by the pressure of the hydraulic fluid discharged from the first pump port 30a, and by connecting the second passage 62 on the downstream side of the second check valve 72 and the tank 50, It is a so-called discharge valve that discharges the hydraulic oil in the rod-side chamber 11 b to the tank 50 . Further, the second pilot check valve 76 blocks the communication between the second passage 62 and the tank 50 when hydraulic oil is not discharged from the first pump port 30a, and the second pilot check valve 76 on the downstream side of the second check valve 72 blocks communication. It also functions as a pressure holding valve that holds the pressure in the second passage 62, that is, the pressure of the working oil in the rod side chamber 11b.

The first pilot check valve 75 is electrically operated so that it opens when hydraulic fluid is discharged from the second pump port 30b and closes when hydraulic fluid is not discharged from the second pump port 30b. It may be a controlled solenoid valve, and the second pilot check valve 76 is opened when hydraulic fluid is being discharged from the first pump port 30a, and hydraulic fluid is not being discharged from the first pump port 30a. It may be a solenoid valve that is electrically controlled to occasionally close. Also, the first and second pilot check valves 75 and 76 allow or block communication between the first passage 61 on the downstream side of the first check valve 71 and the tank 50 according to the discharge state of the pump 30. and can allow or block communication between the second passage 62 on the downstream side of the second check valve 72 and the tank 50 .

Further, the pump unit 100 includes a third discharge passage 67 as a discharge passage where the first and second discharge passages 65 and 66 join on the downstream side of the first and second pilot check valves 75 and 76, and a third discharge passage 67 as a discharge passage. A filter 77 provided in the passage 67 and a discharge check valve 78 provided in parallel with the filter 77 are provided.

The filter 77 removes contaminants such as metal powder contained in the hydraulic oil. The discharge check valve 78 bypasses the filter 77 by opening when the pressure in the third discharge passage 67 on the upstream side of the filter 77 reaches a predetermined pressure when the filter 77 is clogged. It is a so-called safety valve that discharges to the tank 50 .

Further, the pump unit 100 includes a first relief passage 68 as a relief passage branching from the first passage 61 downstream of the first check valve 71 and connecting the first passage 61 and the tank 50, and a second reverse check valve 71. A second relief passage 69 as a relief passage branching from the second passage 62 on the downstream side of the stop valve 72 and connecting the second passage 62 and the tank 50, and the first and second relief passages 68, 69 are provided respectively. and the first and second relief valves 79 and 80 as relief valves.

The first relief valve 79 opens when the pressure of the hydraulic fluid in the first passage 61 on the downstream side of the first check valve 71, that is, the pressure of the hydraulic fluid in the piston-side chamber 11a reaches a predetermined pressure. and discharges hydraulic oil in the first passage 61 on the downstream side of the first check valve 71 to the tank 50, which is a so-called safety valve.

The second relief valve 80 opens when the pressure of the hydraulic fluid in the second passage 62 on the downstream side of the second check valve 72, that is, the pressure of the hydraulic fluid in the rod side chamber 11b reaches a predetermined pressure. It is a so-called safety valve that discharges hydraulic oil in the second passage 62 on the downstream side of the second check valve 72 to the tank 50 .

Next, control of the hydraulic cylinder 10 by the cylinder control device 1 having the hydraulic circuit described above will be described.

The cylinder control device 1 drives the electric motor 20 in the positive direction R1 when receiving an instruction to extend the hydraulic cylinder 10 from an operator or an external control device. When the electric motor 20 is driven in the positive direction R1, the pump 30 sucks hydraulic oil through the first intake check valve 73 and discharges the hydraulic oil from the first pump port 30a. Hydraulic oil discharged from the first pump port 30a is supplied through the first check valve 71 to the piston side chamber 11a.

Further, at this time, the hydraulic oil discharged from the first pump port 30a opens the second pilot check valve 76 . Therefore, the hydraulic oil in the rod side chamber 11b is discharged to the tank 50 through the second pilot check valve 76 and the filter 77. As shown in FIG. At this time, the second passage 62, the second discharge passage 66, the third discharge passage 66, the second discharge passage 66, and the second passage 62 connecting the rod side chamber 11b and the second discharge passage 66, which lead the hydraulic oil in the rod side chamber 11b to the tank 50 The discharge passage 67 corresponds to the discharge passage.

By supplying hydraulic fluid to the piston side chamber 11a and discharging hydraulic fluid in the rod side chamber 11b in this manner, the hydraulic cylinder 10 extends.

On the other hand, the cylinder control device 1 drives the electric motor 20 in the reverse direction R2 when receiving an instruction to contract the hydraulic cylinder 10 from an operator or an external control device. When the electric motor 20 is driven in the reverse direction R2, the pump 30 sucks working oil through the second intake check valve 74 and discharges the working oil from the second pump port 30b. The hydraulic oil discharged from the second pump port 30b is supplied through the second check valve 72 to the rod side chamber 11b.

At this time, the first pilot check valve 75 is opened by the hydraulic oil discharged from the second pump port 30b. Therefore, the hydraulic fluid in the piston side chamber 11 a is discharged to the tank 50 through the first pilot check valve 75 and the filter 77 . At this time, the first passage 61, the first discharge passage 65, and the third The discharge passage 67 corresponds to the discharge passage.

By supplying hydraulic fluid to the rod-side chamber 11b and discharging hydraulic fluid in the piston-side chamber 11a in this way, the hydraulic cylinder 10 contracts.

Further, the cylinder control device 1 stops driving the electric motor 20 when receiving an instruction to stop the hydraulic cylinder 10 from an operator or an external control device. When the electric motor 20 stops, the pump 30 also stops discharging hydraulic oil. At this time, the first check valve 71 and the first pilot check valve 75 prevent the hydraulic oil in the piston-side chamber 11 a from flowing toward the pump 30 and the tank 50 . Further, the second check valve 72 and the second pilot check valve 76 prevent the hydraulic oil in the rod side chamber 11b from flowing toward the pump 30 and the tank 50 .

In this way, the hydraulic cylinder 10 stops and its position is held by preventing the hydraulic fluid from flowing out from the piston-side chamber 11a and the rod-side chamber 11b.

In addition, when the load on the hydraulic cylinder 10 increases and the pressure of the hydraulic oil in the piston side chamber 11a or the rod side chamber 11b exceeds the allowable value of the hydraulic cylinder 10, the first relief valve 79 or the second relief valve 80 By opening the valve, the pressure increase in the hydraulic cylinder 10 is suppressed, and the hydraulic cylinder 10 is prevented from being damaged.

Next, a specific structure of the pump unit 100 will be described with reference to FIGS. 2 to 5. FIG. FIG. 2 is a cross-sectional view of the pump unit 100. As shown in FIG. 3 is a cross-sectional view along line III-III in FIG. 2, FIG. 4 is a cross-sectional view along line IV-IV in FIG. 2, and FIG. 5 is a cross-sectional view along line VV in FIG. It is a diagram.

As shown in FIG. 2, the pump 30 of the pump unit 100 is a swash plate type piston pump. The pump 30 accommodates a shaft 31 as a rotating shaft that is connected to the electric motor 20, a cylinder block 32 that is connected to the shaft 31 and rotates as the shaft 31 rotates, and a bearing 34 that houses the cylinder block 32. It has a case 33 that rotatably supports the shaft 31, and a base block 35 that seals an opening of the case 33 and has an insertion hole 35a through which the shaft 31 is inserted.

The shaft 31 is provided so as to pass through the base block 35, and the electric motor 20 is connected to an end portion 31a as a connecting portion projecting from the base block 35 to the outside. The end portion 31a side of the shaft 31 is rotatably supported via a bearing 36a provided in the insertion hole 35a. Further, leakage of hydraulic oil to the outside through the gap between the shaft 31 and the base block 35 is prevented by an oil seal 36b provided in the insertion hole 35a.

A plurality of cylinders 37 having openings on one end surface are formed in the cylinder block 32 in parallel with the shaft 31 . A plurality of cylinders 37 are formed at predetermined intervals in the circumferential direction of the cylinder block 32 . A columnar piston 38 defining a volume chamber 37a is inserted into the cylinder 37 so as to reciprocate. The tip side of the piston 38 protrudes from the opening of the cylinder 37, and a spherical seat 38a is formed at the tip.

The pump 30 further includes a shoe 39 rotatably connected to the spherical seat 38a of the piston 38, a swash plate 40 with which the shoe 39 slides as the shaft 31 rotates, and an annular ring holding all the shoes 39. It has a retainer plate 41 , a retainer holder 42 that axially presses the retainer plate 41 , and a spring 43 that biases the retainer holder 42 toward the retainer plate 41 .

The swash plate 40 is fixed to the inner wall of the case 33 and has a sliding contact surface 40 a that is inclined from the direction perpendicular to the axis of the shaft 31 . The flat plate portion of the shoe 39 is in surface contact with the sliding contact surface 40a.

A valve plate 45 with which the base end surface of the cylinder block 32 is in sliding contact is fixed to the base block 35 . The valve plate 45 is formed with first and second pump ports 30 a and 30 b (not shown) that communicate with the first and second passages 61 and 62 formed in the base block 35 . In addition, as shown in FIG. 4, the base block 35 includes a first intake check valve 73 that allows hydraulic oil to flow only from the tank 50 to the second pump port 30b, and a check valve from the tank 50 to the first pump port 30a. and a second intake check valve 74 that allows only the flow of hydraulic oil from

One ends of the first and second intake check valves 73, 74 are open on the outer peripheral surface of the base block 35, and the hydraulic oil in the tank 50 is directed through the first and second intake passages 63, 64 and the first and second intake passages 63, 64. Two passages 61, 62 lead to the first and second pump ports 30a, 30b. Also, as shown in FIG. 4, when the first and second suction passages 63 and 64 are opened on the same surface of the base block 35, the surface of the base block 35 on which the first and second suction passages 63 and 64 are opened. By arranging the pump unit 100 so that the 100 is vertically downward, it is possible to smoothly suck the hydraulic oil from the first and second suction passages 63 and 64 . Although the first and second suction passages 63 and 64 are individually opened to the tank 50, the opening ends of the first and second suction passages 63 and 64 opening to the tank 50 are single. may be integrated into the aisles of the

When the shaft 31 is driven to rotate by the power of the electric motor 20 and the cylinder block 32 rotates, the flat plate portion of each shoe 39 comes into sliding contact with the swash plate 40 and each piston 38 makes a stroke according to the inclination angle of the swash plate 40 . It reciprocates in the cylinder 37 by an amount. The reciprocating motion of each piston 38 increases or decreases the volume of each volume chamber 37a.

When the cylinder block 32 rotates in one direction as the electric motor 20 rotates, the hydraulic oil is sucked into the volume chamber 37a whose volume is expanded through the second pump port 30b, and the volume chamber 37a whose volume is reduced is drawn into the volume chamber 37a. Hydraulic oil is discharged through the 1 pump port 30a. On the other hand, when the cylinder block 32 rotates in the other direction, hydraulic fluid is sucked into the volume chamber 37a whose volume increases through the first pump port 30a, and hydraulic fluid is drawn from the volume chamber 37a whose volume decreases through the second pump port 30b. Dispensed. In this way, in the pump 30, the hydraulic oil is continuously sucked and discharged as the cylinder block 32 rotates. In addition, suction and discharge of the first and second pump ports 30a and 30b are switched according to the rotation direction of the cylinder block 32. As shown in FIG.

As shown in FIG. 2 , the pump unit 100 further includes a valve block 90 to which the pump 30 configured as described above is assembled, and a bottomed cylindrical tank case 51 whose open end is closed by the valve block 90 . The tank case 51 and the valve block 90 form a tank 50 in which hydraulic fluid is stored, and the pump 30 is arranged in this tank 50 . That is, the valve block 90 is assembled with the pump 30 and the tank 50 .

The valve block 90 is a rectangular parallelepiped block in which the passages 61 to 69 are formed and the valve devices 71 to 80 such as check valves are assembled. 2 and 3, the valve block 90 has a first end face 91 facing the tank 50, a second end face 92 located on the opposite side of the first end face 91, and an open end of the first passage 61. A third end surface 94 in which the first supply/discharge port 61a opens; a fourth end surface 95 located on the opposite side of the third end surface 94 and in which the second supply/discharge port 62a that is the opening end of the second passage 62 opens; It has six end faces, a fifth end face 96 to which the first and second pilot check valves 75 and 76 are assembled, and a sixth end face 97 located on the opposite side of the fifth end face 96 .

Further, the valve block 90 is provided with an insertion hole 93 penetrating in a direction orthogonal to the first end surface 91 and the second end surface 92 . The end portion 31 a of the shaft 31 of the pump 30 is inserted through the insertion hole 93 . Further, by assembling the electric motor 20 (not shown) to the second end surface 92 , the drive shaft (not shown) of the electric motor 20 is inserted through the insertion hole 93 . That is, within the insertion hole 93, the shaft 31 of the pump 30 and the drive shaft of the electric motor 20 are connected via a shaft coupling (not shown). In order to accommodate the shaft coupling in the insertion hole 93, the inner diameter of the insertion hole 93 is set larger than the outer diameter of the shaft coupling.

The first end surface 91 of the valve block 90 includes, as shown in FIGS. , 80 and a third mounting surface 91c to which the filter 77 is mounted.

The first assembly surface 91a is a connection surface where the first and second pump ports 30a and 30b (not shown) of the pump 30 and the first and second passages 61 and 62 formed in the valve block 90 are connected. and is the surface where the base block 35 of the pump 30 abuts against the valve block 90 . The position of the pump 30 in the axial direction of the shaft 31 is determined by mounting the pump 30 on the first mounting surface 91a in this way.

A holding hole 91d for holding the first and second relief valves 79, 80 to the valve block 90 is opened in the second assembly surface 91b, and a female screw or the like is processed in the holding hole 91d. there is The first and second relief valves 79, 80 are assembled to the valve block 90 by being screwed into the holding holes 91d. The first and second relief valves 79 and 80 may be assembled to the valve block 90 by press fitting. Also, the positioning of the first and second relief valves 79 and 80 in the axial direction may be performed by the second assembly surface 91 b or by a surface formed within the valve block 90 .

A holding hole 91e for holding the filter 77 to the valve block 90 is opened in the third mounting surface 91c, and a female screw or the like is processed in the holding hole 91e. The filter 77 is attached to the valve block 90 by being screwed into the holding hole 91e. Note that the filter 77 may be assembled to the valve block 90 by press fitting. Further, the positioning of the filter 77 in the axial direction may be performed by the third assembly surface 91 c or by a surface formed inside the valve block 90 .

Here, the first thickness T1, which is the thickness of the valve block 90 in the axial direction of the shaft 31 on the first assembly surface 91a, is the thickness of the valve block 90 in the axial direction of the shaft 31 on the second assembly surface 91b. and a third thickness T3, which is the thickness of the valve block 90 in the axial direction of the shaft 31 at the third assembly surface 91c. In other words, the distance between the second end surface 92 to which the electric motor 20 is assembled and the first mounting surface 91a is the distance between the second end surface 92 and the second mounting surface 91b and the distance between the second end surface 92 and the first mounting surface 91b. It is set shorter than the distance to the 3rd assembly surface 91c.

Making the first thickness T1 equal to the second thickness T2 and the third thickness T3 simplifies the shape of the valve block 90, which is advantageous in terms of manufacturing cost. However, the thicknesses of the second thickness T2 and the third thickness T3 depend on the size of the diameter of the flow path formed in the valve block 90 and the first and second relief valves 79 and 80 connected to the flow path. and the length of the filter 77 assembly thread, it tends to be relatively thick.

If the first thickness T1 is set to the same thickness as the relatively thick second thickness T2 and third thickness T3, the length of the shaft connecting the pump 30 and the electric motor 20 will be increased. If the length of the shaft connecting the pump 30 and the electric motor 20 increases, the shaft tends to become eccentric during high-speed rotation and high load, and the eccentricity of the shaft may damage the bearing 36a and the oil seal 36b. . In order to avoid such a situation, the permissible operating range of the pump unit 100 should be restricted. Become.

In contrast, in the pump unit 100 according to the present embodiment, the first thickness T1 is thinner than the second thickness T2 and the third thickness T3, as described above. Therefore, the length of the shaft connecting the pump 30 and the electric motor 20 can be shortened regardless of the presence or absence of the flow path formed in the valve block 90 and the valve device connected to the flow path. becomes.

By shortening the length of the shaft connecting the pump 30 and the electric motor 20 in this way, the eccentricity of the shaft is suppressed during high-speed rotation and high load, which damages the bearing 36a and the oil seal 36b. can be prevented. In addition, by suppressing the eccentricity of the shaft portion, it becomes possible to expand the allowable operation range of the pump unit 100, and by increasing the maximum rotation speed and maximum load of the pump unit 100, the discharge performance of the pump unit 100 can be improved. can be done.

Further, by making the first thickness T1 thinner than the second thickness T2 and the third thickness T3, a part of the pump 30 is accommodated in the valve block 90. As shown in FIG. By accommodating part of the pump 30 in the valve block 90 in this way, the capacity of the tank 50 formed by the tank case 51 and the valve block 90 can be increased.

Further, since the second thickness T2 and the third thickness T3 can be made thicker than the first thickness T1, the valve block for assembling the first and second relief valves 79 and 80 and the filter 77 can be In addition to securing the thickness of the valve block 90, the thickness of the valve block 90 can be secured in order to form a flow path to which the first and second relief valves 79 and 80 and the filter 77 are connected.

Further, in the pump unit 100, as described above, the second thickness T2 of the valve block 90 at the second mounting surface 91b on which the first and second relief valves 79 and 80 are mounted is set to be greater than the first thickness T1. Since the thickness can be increased, as shown in FIG. placed in overlapping positions.

In this manner, by arranging the first and second relief valves 79 and 80 so as to overlap the first and second pilot check valves 75 and 76 when viewed from the axial direction of the shaft 31, The pump unit 100 can be easily miniaturized compared to the case where they are arranged so that they do not overlap at all when viewed from above. Note that the first and second relief valves 79 and 80 may be arranged at positions overlapping the first and second check valves 71 and 72 when viewed from the axial direction of the shaft 31 . Also in this case, the size of the pump unit 100 can be easily reduced.

Also, in the pump unit 100, the first and second pilot check valves 75, 76 and the first and second check valves 71, 72 are arranged at positions not overlapping the pump 30 when viewed from the axial direction of the shaft 31. It is Therefore, it is possible to make the first thickness T1 thinner. As a result, the length of the shaft connecting the pump 30 and the electric motor 20 can be further shortened.

Note that the first and second pilot check valves 75 and 76 and the first and second check valves 71 and 72 are arranged so that a part thereof overlaps the pump 30 when viewed from the axial direction of the shaft 31. good too. By disposing the first and second pilot check valves 75 and 76 and the first and second check valves 71 and 72 closer to the pump 30 in this way, the pump unit 100 can be made smaller.

Further, in the pump unit 100, the second thickness T2 of the valve block 90 on the second mounting surface 91b and the third thickness T3 on the third mounting surface 91c are the same. By providing the second mounting surface 91b on which the first and second relief valves 79 and 80 are mounted and the third mounting surface 91c on which the filter 77 is mounted on the same plane, the valve block 90 is simplified, and as a result, the manufacturing cost of the valve block 90 can be reduced.

Further, when the swash plate 40 of the pump 30 is arranged on the base block 35 side, and the piston 38 and the cylinder block 32 are arranged on the opposite side of the shaft 31 from the end portion 31a with the swash plate 40 interposed therebetween, the cylinder In order to guide the hydraulic fluid discharged from the volume chamber 37a in the block 32 to the valve block 90, it is necessary to route piping outside the cylinder block 32, for example. Therefore, if the pump 30 is configured such that the swash plate 40 is arranged on the base block 35 side, the pump unit 100 will be enlarged in the radial direction.

On the other hand, the swash plate 40 of the pump 30 of the pump unit 100 is arranged on the opposite side of the base block 35 with the piston 38 and the cylinder block 32 interposed therebetween. That is, the base block 35 , the piston 38 and the cylinder block 32 are arranged between the valve block 90 and the swash plate 40 . Therefore, it is possible to form a passage for guiding hydraulic fluid to the volume chamber 37a and a passage for guiding hydraulic fluid discharged from the volume chamber 37a within the base block 35, and it is necessary to provide these passages while avoiding the swash plate 40. There is no Also, the passage formed in the base block 35 and the passage formed in the valve block 90 can be easily connected simply by assembling the pump 30 to the valve block 90 .

Thus, the pump 30 is configured such that the end 31a of the shaft 31 inserted through the insertion hole 93 of the valve block 90 is provided on the opposite side of the swash plate 40 with the piston 38 and the cylinder block 32 interposed therebetween. By doing so, it is possible to prevent the pump unit 100 from increasing in size in the radial direction, and it is possible to facilitate the processing of the passage connecting the pump 30 and the valve block 90 and the work of connecting the passage. As a result, the manufacturing cost of the pump unit 100 can be reduced.

In addition, by accommodating the shaft coupling that connects the pump 30 and the electric motor 20 in the insertion hole 93 of the valve block 90, the pump 30 and the electric It becomes possible to shorten the length of the shaft portion connecting to the motor 20 . By shortening the length of the shaft connecting the pump 30 and the electric motor 20 in this way, the eccentricity of the shaft is suppressed during high-speed rotation and high load, which damages the bearing 36a and the oil seal 36b. can be prevented.

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

In the pump unit 100 according to this embodiment, the first thickness T1 of the valve block 90 on the first mounting surface 91a for positioning the pump 30 is the thickness of the first thickness T1 on which the first and second relief valves 79 and 80 are mounted. It is formed thinner than the second thickness T2 of the valve block 90 at the second mounting surface 91b and the third thickness T3 of the valve block 90 at the third mounting surface 91c where the filter 77 is mounted.

Therefore, the length of the shaft connecting the pump 30 and the electric motor 20 can be shortened regardless of the presence or absence of the flow path formed in the valve block 90 and the valve device connected to the flow path. becomes. By shortening the length of the shaft connecting the pump 30 and the electric motor 20 in this way, the eccentricity of the shaft is suppressed during high-speed rotation and high load, which damages the bearing 36a and the oil seal 36b. can be prevented. In addition, by suppressing the eccentricity of the shaft portion, it becomes possible to expand the allowable operation range of the pump unit 100, and by increasing the maximum rotation speed and maximum load of the pump unit 100, the discharge performance of the pump unit 100 can be improved. can be done.

Next, a modification of the pump unit 100 according to the above embodiment will be described.

In the modification shown in FIG. 6, a first mounting surface 91a for positioning the pump 30 and a second mounting surface 91b for mounting the first and second relief valves 79 and 80 are provided on the same plane. On the other hand, an assembly surface 92a to which the electric motor 20 is assembled is formed in a portion of the second end surface 92 facing the first assembly surface 91a.

Also in this modification, the first thickness T1 in the axial direction of the shaft 31 of the valve block 90 at the first assembly surface 91a is the second thickness T1 in the axial direction of the shaft 31 of the valve block 90 at the second assembly surface 91b. It is formed thinner than T2. In other words, the distance between the mounting surface 92a on which the electric motor 20 is mounted and the first mounting surface 91a is set shorter than the distance between the second end surface 92 and the second mounting surface 91b. .

Therefore, as in the above embodiment, it is possible to shorten the length of the shaft connecting the pump 30 and the electric motor 20 . By shortening the length of the shaft connecting the pump 30 and the electric motor 20 in this way, the eccentricity of the shaft during high-speed rotation and high load is suppressed, and the bearing 36a and the oil seal 36b are damaged. can be prevented.

Further, in the above embodiment, the case where the pump 30 is a swash plate type piston pump has been described. However, the pump 30 is not limited to a swash plate type piston pump, and may be of any type as long as it is a positive displacement pump capable of discharging hydraulic oil by being rotationally driven. A gear pump or a vane pump may be used.

Configurations, functions, and effects of embodiments of the present invention will be collectively described below.

The pump unit 100 includes a tank 50 that stores hydraulic oil, a pump 30 that is arranged in the tank 50 and can discharge the hydraulic oil in the tank 50 by driving a shaft 31 to rotate by an electric motor 20 , and the electric motor 20 . a valve block 90 to which the pump 30 and the tank 50 are assembled; first and second passages 61 and 62 formed in the valve block 90 that connect the pump 30 and the hydraulic cylinder 10 and through which hydraulic oil discharged from the pump 30 flows; , first, second and third discharge passages 65, 66, 67 formed in the valve block 90 to connect the hydraulic cylinder 10 and the tank 50 and guide the hydraulic oil discharged from the hydraulic cylinder 10 to the tank 50; First and second relief passages 68, 69 formed in the block 90 and branching from the first and second passages 61, 62 and communicating with the tank 50; First and second relief valves 79 and 80 that open when the pressure of the hydraulic fluid in the second passages 61 and 62 reaches a predetermined pressure. The first end face 91 has a first mounting face 91a for positioning the pump 30 in the axial direction of the shaft 31, and a first mounting face 91a for mounting the first and second relief valves 79, 80 on the first end face 91. A second assembly surface 91b is formed, and the first thickness T1 in the axial direction of the shaft 31 of the valve block 90 at the portion where the first assembly surface 91a is formed is It is formed thinner than the second thickness T2 in the axial direction of the shaft 31 of the partial valve block 90 .

In this configuration, the first thickness T1 of the valve block 90 on the first mounting surface 91a for positioning the pump 30 is the same as the thickness on the second mounting surface 91b on which the first and second relief valves 79 and 80 are mounted. It is formed thinner than the second thickness T2 of the valve block 90 . Therefore, the length of the shaft connecting the pump 30 and the electric motor 20 can be shortened regardless of the presence or absence of the flow path formed in the valve block 90 and the valve device connected to the flow path. becomes. By shortening the length of the shaft connecting the pump 30 and the electric motor 20 in this way, the eccentricity of the shaft is suppressed during high-speed rotation and high load, which damages the bearing 36a and the oil seal 36b. can be prevented. In addition, by suppressing the eccentricity of the shaft portion, it becomes possible to expand the allowable operation range of the pump unit 100, and by increasing the maximum rotation speed and maximum load of the pump unit 100, the discharge performance of the pump unit 100 can be improved. can be done.

The pump unit 100 also includes first and second check valves provided in the first and second passages 61 and 62 to prevent hydraulic oil in the first and second passages 61 and 62 from flowing back to the pump 30 side. Valves 71, 72, and first and second pilot check valves 75, 76 capable of discharging hydraulic oil in the first and second discharge passages 65, 66 to the tank 50, The valves 79 and 80 are arranged at positions at least partially overlapping with either one of the first and second check valves 71 and 72 and the first and second pilot check valves 75 and 76 when viewed from the axial direction of the shaft 31. be done.

In this configuration, the first and second relief valves 79 and 80 are any of the first and second check valves 71 and 72 and the first and second pilot check valves 75 and 76 when viewed from the axial direction of the shaft 31 . It is arranged so that at least a part of it overlaps with one of them. In this manner, by arranging the first and second relief valves 79 and 80 so as to overlap the first and second check valves 71 and 72 and the first and second pilot check valves 75 and 76, The pump unit 100 can be easily miniaturized compared to the case where they are arranged so that they do not overlap at all when viewed from the axial direction.

The pump unit 100 also includes first and second check valves provided in the first and second passages 61 and 62 to prevent hydraulic oil in the first and second passages 61 and 62 from flowing back to the pump 30 side. valves 71, 72, and first and second pilot check valves 75, 76 capable of discharging hydraulic oil in the first and second discharge passages 65, 66 to the tank 50; The stop valves 71 , 72 and the first and second pilot check valves 75 , 76 are arranged at positions not overlapping the pump 30 when viewed from the axial direction of the shaft 31 .

In this configuration, the first and second check valves 71 , 72 and the first and second pilot check valves 75 , 76 are arranged at positions not overlapping the pump 30 when viewed in the axial direction of the shaft 31 . Thus, by not arranging the first and second check valves 71 and 72 and the first and second pilot check valves 75 and 76 at positions overlapping the pump 30 when viewed from the axial direction of the shaft 31, the first thickness It is possible to make the thickness T1 even thinner. As a result, the length of the shaft connecting the pump 30 and the electric motor 20 can be further shortened.

The pump unit 100 also includes first and second pilot check valves 75 and 76 capable of discharging hydraulic oil in the first and second discharge passages 65 and 66 to the tank 50, and a third discharge passage 67 provided in the third discharge passage 67. and a filter 77 through which hydraulic oil discharged through the first and second pilot check valves 75 and 76 flows. The third thickness T3 in the axial direction of the shaft 31 of the valve block 90 at the portion where the mounting surface 91c is formed is the third thickness T3 in the axial direction of the shaft 31 of the valve block 90 at the portion where the second mounting surface 91b is formed. 2 is formed to have the same thickness as the thickness T2.

In this configuration, the third thickness T3 in the axial direction of the shaft 31 of the valve block 90 where the third mounting surface 91c is formed is the same as the thickness of the shaft 31 of the valve block 90 where the second mounting surface 91b is formed. It is formed to have the same thickness as the second thickness T2 in the axial direction of 31 . By providing the second mounting surface 91b on which the first and second relief valves 79 and 80 are mounted and the third mounting surface 91c on which the filter 77 is mounted on the same plane, the valve block 90 is simplified, and as a result, the manufacturing cost of the valve block 90 can be reduced.

The pump 30 is a swash plate type piston pump having a piston 38 and a swash plate 40 for reciprocating the piston. is provided on the side opposite to the swash plate 40 with the piston 38 interposed therebetween.

In this configuration, the end 31 a of the shaft 31 of the pump 30 connected to the electric motor 20 is provided on the opposite side of the swash plate 40 with the piston 38 interposed therebetween. That is, the piston 38 and the cylinder block 32 are arranged between the valve block 90 and the swash plate 40 . Therefore, it is possible to easily form a passage for guiding the hydraulic oil discharged from the pump 30 toward the valve block 90, and the passage formed on the pump 30 side can be easily formed by simply assembling the pump 30 to the valve block 90. and the passage formed on the valve block 90 side can be easily connected. As a result, the manufacturing cost of the pump unit 100 can be reduced.

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.

DESCRIPTION OF SYMBOLS 100... Pump unit, 10... Hydraulic cylinder (fluid pressure actuator), 20... Electric motor (driving source), 30... Pump, 31... Shaft (rotating shaft), 31a... End portion (connecting portion) 38 Piston 40 Swash plate 50 Tank 61 First passage (actuator flow path) 62 Second passage (actuator flow path) ), 65... first discharge passage (discharge passage), 66... second discharge passage (discharge passage), 67... third discharge passage (discharge passage), 68... first Relief passage (relief flow path), 69 ... second relief passage (relief flow path), 71 ... first check valve (check valve), 72 ... second check valve (check valve ), 75... First pilot check valve (discharge valve), 76... Second pilot check valve (discharge valve), 77... Filter, 79... First relief valve (relief valve), 80 ... second relief valve (relief valve), 90 ... valve block, 91 ... first end face, 91a ... first assembly surface, 91b ... second assembly surface, 91c ...・Third assembly surface, T1: first thickness, T2: second thickness, T3: third thickness

Claims (4)

A pump unit that supplies a working fluid to a hydraulic actuator,
a tank that stores the working fluid;
a pump arranged in the tank and capable of discharging the working fluid in the tank by rotationally driving a rotating shaft by a driving source;
a valve block to which the driving source, the pump, and the tank are assembled;
an actuator flow path formed in the valve block, connecting the pump and the fluid pressure actuator, and through which a working fluid discharged from the pump flows;
a discharge passage formed in the valve block and communicating between the fluid pressure actuator and the tank and guiding working fluid discharged from the fluid pressure actuator to the tank;
a relief channel formed in the valve block and branching from the actuator channel and communicating with the tank;
a relief valve that is provided in the relief channel and opens when the pressure of the working fluid in the actuator channel reaches a predetermined pressure;
a check valve provided in the actuator flow path to prevent a working fluid in the actuator flow path from flowing back to the pump;
a discharge valve capable of discharging the working fluid in the discharge passage to the tank;
with
the valve block has a first end face facing the inside of the tank,
On the first end face,
a first mounting surface for positioning the pump in the axial direction of the rotating shaft;
a second mounting surface to which the relief valve is mounted;
The thickness of the portion of the valve block on which the first mounting surface is formed in the axial direction of the rotating shaft of the valve block is formed thinner than the thickness ,
A pump unit according to claim 1, wherein the check valve and the discharge valve are arranged at positions not overlapping with the pump when viewed from the axial direction of the rotating shaft . 2. The pump unit according to claim 1 , wherein the relief valve is arranged at a position where at least a portion of the relief valve overlaps with one of the check valve and the discharge valve when viewed from the axial direction of the rotating shaft. . further comprising a filter provided in the discharge channel and through which the working fluid discharged through the discharge valve flows;
A third mounting surface to which the filter is mounted is formed on the first end surface,
The thickness of the portion of the valve block on which the third mounting surface is formed in the axial direction of the rotating shaft of the valve block is 3. The pump unit according to claim 1, wherein the thickness is the same as the thickness. The pump is a swash plate type piston pump having a piston and a swash plate for reciprocating the piston,
The rotating shaft has a connecting portion connected to the drive source,
The pump unit according to any one of claims 1 to 3 , wherein the connecting portion is provided on a side opposite to the swash plate with the piston interposed therebetween.

Images