JPH11218073A - Pump / motor device - Google Patents

Abstract

(57) [Summary] To provide a compact pump / motor device. SOLUTION: A case 1 and first and second end covers 2 are provided.
3, a housing 4 is provided, in which a first valve plate 9, a first cylinder block 5, a swash plate 8, a second cylinder block 6, and a second valve plate 10 are sequentially provided in the left-right direction. 11 is supported so as to rotate together with the first and second cylinder blocks 5 and 6, and the first sliding guide surface 20 and the second sliding guide surface 24 of the swash plate 8 are substantially V-shaped. The first pump / motor A and the second pump / motor B share a shaft 7 and a swash plate 8 to form a compact pump / motor device.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pump / motor device used for reuse of return pressure oil from a hydraulic actuator.

[0002]

2. Description of the Related Art As shown in Japanese Patent Publication No. 33392/1991, a pump having a first pump motor and a second pump motor mechanically connected to rotate at the same rotational speed.
A motor device has been proposed. With this pump / motor device, the first pump / motor is driven by the return pressure oil of the hydraulic actuator, thereby driving the second pump / motor to store high-pressure oil in the pressure accumulator. Since the second pump / motor can be driven by the oil and the first pump / motor can be driven to supply the high-pressure oil to the hydraulic actuator side, the return pressure oil from the hydraulic actuator can be reused.

[0003]

Problems to be Solved by the Invention
No. 922 discloses a pump / motor device in which a first axial plunger pump motor and a second axial plunger pump / motor are axially connected via a connection block, and a first / second axial plunger pump is provided.・ The shaft of the motor is common, and when one works as a pump, the other works as a motor.Therefore, the number of parts is large and the cost is high, and the length in the axial direction is long and large. The volume increases.

Therefore, an object of the present invention is to provide a pump / motor device which can solve the above-mentioned problems.

[0005]

According to a first aspect of the present invention, a first cylinder block 5 and a second cylinder block 6 are rotatably supported together with a shaft 7 in a housing 4. A swash plate 8 having a first sliding guide surface 20 and a second sliding guide surface 24 that are not parallel to each other is provided between the swash plate 8 and the second cylinder block 6. The first sliding guide surface 2 is movably inserted into the piston 16.
The first pump / motor A is slidable along 0,
A second pump / motor B in which a piston 16 slidably fitted in a cylinder hole 15 of the second cylinder block 6 is slidable along the second sliding guide surface 24. -It is a motor device.

According to the first invention, the first cylinder block 5 of the first pump / motor A and the second cylinder block 6 of the second pump / motor B are connected by the shaft 7 and rotate at the same rotational speed. Therefore, the first pump / motor A and the second pump / motor B are mechanically connected to each other to provide a pump / motor device that rotates at the same rotation speed.

Since the swash plate 8 of the first pump-motor A and the second pump-motor B is common, the number of parts is small and the cost is low, and the axial length is short and compact.
Can be installed in small volume installation locations.

A second aspect of the present invention is the pump / motor apparatus according to the first aspect, wherein the swash plate 8 is provided so as to be swingable, and a swash plate swinging device 80 for swinging the swash plate 8 is attached to the housing 4. .

According to the second aspect of the present invention, one angle of the first and second sliding guide surfaces 20, 24 is increased and the other angle is decreased by swinging the swash plate 8, so that the first pump is provided. -Increase the capacity of one of the motor A and the second pump / motor B,
The other can be controlled smaller.

According to a third invention, two main ports for a first pump / motor, two main ports for a second pump / motor, and one first pump / motor are provided in the housing 4 in the first invention. Pump having a communication hole 79 for communicating a main port for communication with a main port for one second pump / motor.
It is a motor device.

According to the third aspect, one main port for the first pump / motor and one main port for the second pump / motor communicate with each other through the communication hole 79 of the housing 4. There is no need for piping that connects the ports,
In the case of a pump / motor device of a hydraulic system for recovering return pressure oil or a hydraulic system for diverting and supplying discharge pressure oil of a hydraulic pump, piping is simplified.

According to a fourth aspect of the present invention, in the first aspect, a first valve plate 9 and a second valve plate 10 are mounted on both left and right sides in the housing 4, and the first cylinder block 5 is moved along the first valve plate 9. The second cylinder block 6 is rotatably supported along the second valve plate 10, and a swash plate 8 is provided between the first cylinder block 5 and the second cylinder block 6. .Holes 12 in the second cylinder blocks 5 and 6
And a swash plate 8 in which a shaft 7 is inserted, and both ends of the shaft 7 are rotatably supported on first and second valve plates 8 and 10 by bearings 14.

According to the fourth aspect, the housing 4 has the shaft 7
No space is required to support both ends of the housing 4, and the axial length of the housing 4 is shortened accordingly.

According to a fifth aspect of the present invention, in the first aspect, a first end cover 2 and a second end cover 3 are detachably attached to both end surfaces of the case 1 to form a housing 4, and the first end cover 2 is attached to the first end cover 2. A first and second main ports (40, 41) for one pump / motor are formed, and third and fourth main ports (60, 61) for a second pump / motor are formed in the second end cover (3). It is a pump motor apparatus of description.

According to the fifth aspect, the first and second main ports 40 and 41 and the first and second main ports are exchanged by replacing the first end cover 2 and the second end cover 3 with the case 1 being common. The ports 60 and 61 can be set to an arbitrary communication state, and the first and second end covers are pump / motor devices used for a return pressure oil recovery hydraulic system, a hydraulic pump discharge pressure oil split flow supply hydraulic system, and the like. It can be produced by replacing 2 and 3.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, a cylindrical case 1 having both ends opened, a first end cover 2 detachably attached to one end surface 1a of the case 1 with bolts and the like, A housing 4 is formed by a second end cover 3 which is detachably attached to the other end surface 1b of the first member 1 with bolts or the like.

A first cylinder block 5 and a second cylinder block 6 are provided in the housing 4 so as to be rotatable together with a shaft 7. A swash plate 8 is provided between the first cylinder block 5 and the second cylinder block 6. Is provided. The first cylinder block 5 is rotatable along a first valve plate 9 supported by the first end cover 2 so as not to rotate, and the second cylinder block 6 is supported by the second end cover 3 so as not to rotate. It is rotatable along the second valve plate 10.

The shaft 7 has a large diameter at an intermediate portion in the axial direction and small diameters at both ends, and a spline 7a is formed at the large diameter intermediate portion. The holes 12 of the first and second cylinder blocks 5 and 6 are stepped holes having a small-diameter portion 12a and a large-diameter portion 12b. A spline is formed in the small-diameter portion 12a, and the shaft 12 is spline-fitted. The hole 11 of the valve plate 8 has a larger diameter than the shaft 7.

As described above, the first and second cylinder blocks 5, 6 and the shaft 7 rotate integrally, and the swash plate 8 can swing in the axial direction of the shaft 7.

The shaft 7 is inserted through the hole 11 of the swash plate 8 and the hole 12 of the axis of the first and second cylinder blocks 5 and 6, and one end is rotated by a bearing 14 into the hole 13 of the first valve plate 9. The other end is rotatably supported by a bearing 14 in a hole 13 of the second valve plate 10.

A plurality of cylinder holes 15 are formed in the first cylinder block 5, and a piston 16 is inserted into each cylinder hole 15 to form a piston chamber 17. A piston shoe 18 is swingably attached to each piston 16, and the piston shoe 18 is slidably pressed against a first sliding guide surface 20 of the swash plate 8 by a shoe retainer 19. The piston chambers 17 pass through the ports 21 to rotate the first cylinder block 5 to rotate the first and second kidney ports 22 and 2 of the first valve plate 9.
3 alternately communicates. This constitutes the first pump / motor A.

The second cylinder block 6 is the same as the first cylinder block 5, and its piston shoe 1
8 is slidably pressed against the second sliding guide surface 24 of the swash plate 8, and the piston chamber 17 alternately communicates with the first kidney port 22 and the second kidney port 23 of the second valve plate 10. This constitutes the second pump / motor B.

The first sliding guide surface 20 of the swash plate 8 and the second sliding guide surface 20
The sliding guide surface 24 is inclined at a predetermined angle with respect to the axis perpendicular to the axis of the shaft 7, and the angles are different from each other. In other words, the first sliding guide surface 20 and the second sliding guide surface 24 are not parallel to each other but have a substantially C shape.

As shown in FIGS. 2 and 3, a pair of circular openings 30 are formed in the middle of the case 1 in the axial direction. It is fixed at 32. The swash plate 8 is provided with a pair of support shafts 33, each of which is provided with a concave portion 34 of the cap 30.
The swash plate 8 is rotatably supported by a bearing 35 on the shaft 7.
Is supported by the case 1 so as to be swingable in the axial direction.

A swash plate sensor 36 for detecting the tilt angle of the swash plate 8 is attached to the one cap 31. The shaft 7
Has one end protruding into the first end cover 2, and a rotation sensor 37 for detecting rotation of the shaft 7 such as an electromagnetic pickup is attached to the first end cover 2.

As shown in FIG. 2, the first end cover 2 has a first main port 40 communicating with the first kidney port 22 of the first valve plate 9 and a second main port 40 communicating with the second kidney port 23.
A main port 41 is formed. The first main port 40 is shown in FIG.
As shown in the figure, the oil hole 42 opens to the case joining surface 2a of the first end cover 2.

The second main port 41 is a charge valve 43 provided on the first end cover 2 and an inlet port 44 shown in FIG.
And one of the outlet ports 45. The charge valve 43 has a spool 47 inserted into a spool hole 46 of the first end cover 2, and the spool 47 is moved downward by a spring 48 to move the inlet port 44 and the second main port 4.
When the pilot pressure oil is supplied to the pressure receiving chamber 49, the spool 47 moves upward to communicate the second main port 41 and the outlet port 45.

The pilot pressure oil is supplied to the pressure receiving chamber 49 by an electromagnetic switching valve 50. This electromagnetic switching valve 50 is shown in FIG.
As shown in FIG.
The main body 51 is moved by the first end cover 2 to move the inflow port 54 to communicate with the outflow port 55.
On the mounting surface 2b. The inflow port 54 communicates with the inflow oil hole 56, and the outflow port 55 communicates with the pressure receiving chamber 49 through the outflow oil hole 57.

As shown in FIG. 2, the second end cover 3 has a third main port 60 communicating with the first kidney port 22 of the second valve plate 10 and a fourth main port 61 communicating with the second kidney port 23. It is formed. As shown in FIG. 1, the third main port 60 opens to the case joining surface 3 a of the second end cover 3 through an oil hole 62.

The fourth main port 61 is a charge valve 63 provided on the second end cover 3 and an outlet port 64 shown in FIG.
And is cut off. The charge valve 63 has a spool 66 inserted into a spool hole 65 of the second end cover 3, and the spool 66 is moved downward by a spring 67 to shut off the outlet port 64 and the fourth main port 61. When the pilot pressure oil is supplied, the spool 66 moves upward to connect the fourth main port 61 to the outlet port 64.

The pilot pressure oil is supplied to the pressure receiving chamber 68 by an electromagnetic switching valve 69. This electromagnetic switching valve 69 is shown in FIG.
As shown in FIG.
And the main body 70 is moved by the second end cover 3 to move the inflow port 73 to communicate the inflow port 73 with the outflow port 74.
On the mounting surface 3b. The inflow port 73 communicates with the inflow oil hole 75, and the outflow port 74 communicates with the pressure receiving chamber 68 through the outflow oil hole 76.

The second end cover 3 has an outlet port 6
A first relief valve 77 for relieving the pressure oil of No. 4 and a second relief valve 78 for relieving the pressure oil of the fourth main port 61 are attached.

The case 1 is formed with a communication oil hole 79 penetrating through one end surface 1a and the other end surface 1b. The oil hole 42 and the oil hole 62 communicate with each other through the communication oil hole 79. The first main port 40 and the third main port 60 are in communication.

As shown in FIG. 1, a swash plate swinging device 80 for swinging the swash plate 8 is attached to the case 1. As shown in FIGS. 1 and 8, the swash plate swinging device 80 has a servo piston 83 slidably fitted in a cylinder hole 82 of an apparatus body 81 provided integrally with the case 1, and The provided mover 84 is swingably fitted and connected to the recess 8 a of the swash plate 8.

The servo piston 83 includes a spring 85
And the right and left chambers 87 and 88 have a first pump motor A and a second pump motor B, respectively.
Is supplied from the port 89.

A spool hole 90 is formed in the axis of the servo piston 83, and a spool 91 is inserted into the spool hole 90. An annular inlet 92 formed in the spool hole 90 communicates with the right chamber 88 via a slit 93 formed on the outer peripheral surface of the servo piston 83, an annular groove 94 of the cylinder hole 82, and an oil hole 95. The spool 9
1 has an outlet 96 formed therein, and the outlet 96 is formed in the shaft hole 9.
7, and communicates with the drain port 98.

The spool 91 is pushed by a spring 99 in a direction in which the inflow port 92 and the outflow port 96 are shut off.
The pilot pressure oil of 00 pushes the inflow port 92 and the outflow port 96 in a direction communicating with each other. A pilot pressure is supplied to the pressure receiving section 100 by an electromagnetic proportional pressure control valve 101, and constitutes a variable pressure reducing valve 102 for reducing the pressure in the right chamber 88.

The pressure receiving portion 100 is formed by an annular groove formed between a large diameter portion 91a near the one end of the spool 91 and a small diameter portion 91b.

The electromagnetic proportional pressure control valve 101 has a valve body 10
3 is pushed by a spring 105 to a position where the inlet port 106 and the outlet port 107 are shut off,
The spool 104 is connected to the inlet port 1 by the solenoid 108.
06 and the outlet port 107 are pushed in the direction of communication. The inlet port 106 has an inflow oil hole 109
And pressure oil is supplied from a hydraulic source (not shown). The outlet port 107 has an oil spill hole 110, an annular groove 111,
It communicates with the pressure receiving unit 100 via the slit 112.

As described above, the pilot pressure having a pressure proportional to the amount of current supplied to the solenoid 108 is applied to the outlet port 107.
From the pressure receiving unit 100. The spool 91 communicates the inflow port 92 with the outflow port 96 by the pilot pressure supplied to the pressure receiving section 100 to reduce the pressure in the right chamber 88.

As a result, the servo piston 83 moves to the right and cuts off the inflow port 92 and the outflow port 96, so that the servo piston 83 moves to the right by a stroke proportional to the pilot pressure supplied to the pressure receiving section 100. I do. FIG. 8 shows a state in which the servo piston 83 has moved most to the right.

When the servo piston 83 moves to the right, the swash plate 8 swings, and the angle of the first and second sliding guide surfaces 20, 24 is changed so that one is large and the other is small.
The capacity of the pump motor A and the capacity of the second pump motor B are large on one side and small on the other side.

Therefore, by controlling the amount of current supplied to the solenoid 108 of the electromagnetic proportional pressure control valve 101, the capacities of the first pump motor A and the second pump motor 1B can be continuously controlled to increase one and decrease the other. .

FIG. 9 is a schematic diagram of the above-described pump / motor device. The inlet port 44 is connected to the return circuit 110 of the actuator, and the outlet port 4 is connected.
5 is connected to the discharge path 112 of the main hydraulic pump 111, and the outlet port 64 is connected to the accumulator 113, so that the return pressure oil of the actuator is recovered and the main hydraulic pump 11 is connected.
A pressure oil recovery and reuse system for supplying to one discharge path 112 can be provided.

Specifically, the collection check valve 114 is opened, and the inlet port 44 and the outlet port 45 of the charge valve 43 are opened.
And the outlet port 64 of the charge valve 63 communicates with the fourth main port 61 of the second pump port B.
The return pressure oil of the actuator flows into the second main port 41 of the first pump / motor A, and the first pump / motor A operates as a motor to drive the second pump / motor B. At this time,
By reducing the capacity of the second pump / motor B, high-pressure oil is discharged when driven by the same drive torque.

Thus, the second pump / motor B operates as a pump, discharges high-pressure oil to the fourth main port 61, and stores high-pressure oil in the accumulator 113. At this time, when the accumulator 113 becomes full of high-pressure oil, the fourth main port 6
1 becomes higher than the set pressure of the relief valve 78,
Relieve the tank.

Next, the collection check valve 114 is closed, and the inlet port 44 of the charge valve 43 is connected to the outlet port 45.

As a result, the high-pressure oil stored in the accumulator 113 flows into the fourth main port 61 of the second pump / motor B, and the second pump / motor B operates as a motor. Drive.

The second pump / motor A functions as a pump to discharge high-pressure oil to the second main port 41, and the high-pressure oil is supplied from the charge valve 43 to the discharge path 112 of the main hydraulic pump 111. At this time, the pressure of the discharge path 112 and the second main port 4
The displacement of the second pump / motor B is controlled so that the pressures of the first and second pumps are equal (or the pressure of the second main port 41 is slightly higher).

Next, a second embodiment of the swash plate swinging device 80 will be described with reference to FIG. Pressure receiving part 1 of spool 91
00 through the slit 112 and the annular groove 111
30 and supply or not supply pilot pressure oil to the circulation oil hole 130.

In this way, if the pilot pressure oil is supplied to the inflow oil hole 130, the servo piston 83 moves to the position shown in the figure. If the pilot pressure oil is not supplied, the servo piston 83 moves to the left. The swash plate 8 can be swung in two stages.

Next, a second embodiment of the present invention will be described. As shown in FIGS. 11 to 15, the internal structure of the case 1 is the same as that of the first embodiment, and the first main port 40 of the first end cover 2 has an oil hole 140 and a side surface of the first end cover 2. And the second main port 41 communicates with the communication hole 79 of the case 1 through the oil hole 141.

The third main port 60 of the second end cover 3,
The fourth main port 61 is opened on the side surface of the second end cover 3 by oil holes 142 and 143, and the fourth main port 61 is formed by oil holes 144.
Communicates with the communication hole 79 of the case 1. The rotation sensor 37 and the swash plate sensor 36 are not attached.

As shown in FIGS. 12 and 16, the swash plate swinging device 80 has a servo piston 83 inserted into a cylinder hole 82 of an apparatus main body 81, and a movable element 84 provided in the servo piston 83 is attached to the swash plate 8 as shown in FIG. It is swingably fitted in the recess 8a.

The servo piston 83 includes the left and right springs 8.
5, the high pressure oil of the first pump motor A and the higher pressure oil of the second pump motor B are supplied to the left chamber 87 and the right chamber 88. Variable pressure reducing valves 102 similar to those of the first embodiment are provided near the left and right sides of the servo piston 83, respectively, so as to reduce the pressure in the left chamber 87 and the right chamber 88.

More specifically, a pair of left and right spools 91 are fitted into spool holes 90 of the servo piston 83, respectively.
Pilot pressure oil is formed in each pressure receiving portion 100 from the first and second oil holes 145 and 146, respectively, and the left variable pressure reducing valve 102 for reducing the pressure in the left chamber 89 and the right variable pressure reducing valve 102 for reducing the pressure in the right chamber 88. Each of the pressure reducing valves 102 is formed.

As described above, when the pilot pressure oil is supplied from the first oil hole 145, the variable pressure reducing valve 102 on the left side reduces the pressure in the left side chamber 87.
3 slides to the left, and when the pilot pressure oil is supplied from the second oil hole 146, the right variable pressure reducing valve 102 reduces the pressure in the right chamber 88, so that the servo piston 83 slides to the right.

Therefore, the swash plate 8 is swung so that its first
By changing one of the angles of the second sliding guide surfaces 20, 24 to be large and the other to be small, the capacities of the first and second pump motors A, B can be continuously controlled to be large for one and small for the other.

FIG. 17 is a diagrammatic view of the above-described pump / motor device. The discharge passage 151 of the main hydraulic pump 150 is connected to the communication passage 79, and the first and third main ports 40, 60 is connected to the first and second actuators 154 and 156 via the first and second operation valves 152 and 153, so that the discharge pressure oil of one main hydraulic pump 150 can be connected to the first and second actuators having different loads. 154,1
55 at the same time.

Thus, by replacing the first and second end covers 2 and 3, a pump / motor device of the pressure oil recovery / reuse system and a pump / motor device of the pressure oil distribution system can be obtained. .

Next, a second embodiment of the swash plate swinging device 80 will be described with reference to FIG. Plugs 147 are screwed into left and right ends of the cylinder hole 82 of the apparatus main body 81, respectively, and the servo piston 83 is held so as not to move.

In this manner, the angle of the swash plate 8 becomes constant, and the lock nut 148 is loosened to allow the one plug 14
By screwing the plug 7 and loosening the other plug 147, the servo piston 83 can be moved to change the angle of the swash plate 8.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view of a pump / motor device showing a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line CC of FIG.

FIG. 3 is a sectional view taken along line DD of FIG. 1;

FIG. 4 is a left side view of FIG. 1;

FIG. 5 is a right side view of FIG. 1;

FIG. 6 is a sectional view taken along the line EE of FIG. 1;

FIG. 7 is a sectional view taken along line FF of FIG. 1;

FIG. 8 is a sectional view taken along the line GG of FIG. 1;

FIG. 9 is an explanatory diagram schematically showing a pump / motor device.

FIG. 10 is a sectional view showing a second embodiment of the swash plate rocking device.

FIG. 11 is a longitudinal sectional view of a pump / motor device according to a second embodiment of the present invention.

FIG. 12 is a sectional view taken along the line HH in FIG. 11;

FIG. 13 is a sectional view taken along line II of FIG. 11;

FIG. 14 is a left side view of FIG. 11;

FIG. 15 is a right side view of FIG.

FIG. 16 is a sectional view taken along the line JJ of FIG. 11;

FIG. 17 is an explanatory diagram schematically showing a pump / motor device.

FIG. 18 is a cross-sectional view showing a second embodiment of the swash plate rocking device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Case 2 ... 1st end cover 3 ... 2nd end cover 4 ... Housing 5 ... 1st cylinder block 6 ... 2nd cylinder block 7 ... Shaft 8 ... Swash plate 9 ... 1st valve plate 10 ... 2nd valve plate 11 ... Hole 12 ... Hole 14 ... Bearing 15 ... Cylinder hole 16 ... Piston 18 ... Piston shoe 20 ... First sliding guide surface 24 ... Second sliding guide surface 30 ... Opening 31 ... Cap 33 ... Support shaft 40 ... First Main port 41 Second main port 43 Charge valve 60 Third main port 61 Fourth main port 63 Charge valve 79 Communication hole 80 Swash plate rocking device 83 Servo piston 84 Moving element 87 Left side Chamber 88 Right side chamber 90 Spool hole 91 Spool 100 Pressure receiving unit 101 Electromagnetic proportional pressure control valve 102 Variable pressure reducing valve 110 Return circuit 111 Main hydraulic pump 113 Aki Enumerator 130 Inflow oil hole 145 First oil hole 146 Second oil hole 147 Plug 150 Main hydraulic pump 152 First operation valve 153 Second operation valve 154 First actuator 155 Second actuator

Claims (5)

[Claims] 1. A first cylinder block (5) and a second cylinder block (6) are rotatably supported together with a shaft (7) in a housing (4), and the first cylinder block (5) and a second cylinder block are supported. A first sliding guide surface (20) and a second
A swash plate (8) having a sliding guide surface (24) is provided, and a cylinder hole (1) of the first cylinder block (5) is provided.
5) The piston (16) slidably fitted in the first
The first pump / motor (A) is slidable along the sliding guide surface (20), and the cylinder hole (1) of the second cylinder block (6) is provided.
5) The piston (16) slidably fitted in the second
A pump / motor device comprising a second pump / motor (B) slidable along a sliding guide surface (24). 2. A swash plate swinging device (8) for swinging the swash plate (8) in the housing (4).
The pump / motor device according to claim 1, further comprising (0). 3. A housing (4) having two main ports for the first pump motor, two main ports for the second pump motor, one main port for the first pump motor and one main port. The pump / motor device according to claim 1, wherein a communication hole (79) communicating with the main port for the second pump / motor is formed. 4. A first valve plate (9) and a second valve plate (10) are mounted on both left and right sides in the housing (4), and the first cylinder block (5) is moved along the first valve plate (9). The second cylinder block (6) is rotatably supported and the second valve plate (1) is
0), the swash plate (8) is provided between the first cylinder block (5) and the second cylinder block (6), and the first and second cylinder blocks (5), The shaft (7) is inserted through the hole (12) of (6) and the hole (11) of the swash plate (8), and both ends of the shaft (7) are connected to the first and second valve plates (8),
The pump / motor device according to claim 1, wherein the bearing is rotatably supported by a bearing (9). 5. A housing (4) having a first end cover (2) and a second end cover (3) removably attached to both end surfaces of a case (1), and a first end cover (2) attached to the first end cover (2). First and second main ports (40) and (41) for one pump / motor are formed, and the second end cover (3) is provided with a third port for second pump / motor.
-The fourth main port (60), (61) is formed.
The pump / motor device according to any one of the preceding claims.