JP5265609B2 - Fluid pressure generator - Google Patents

Description

  The present invention relates to a fluid pressure generator including an electric motor and a fluid pressure pump.

  2. Description of the Related Art Conventionally, a hydrotransformer composed of an electric motor, an axial piston motor, and an axial piston pump, and a hydrotransformer in which respective rotation shafts of the electric motor, the axial piston motor, and the axial piston pump are connected in series is known ( For example, see Patent Document 1.)

  In addition, it is a fluid pressure servo pump composed of an electric motor and an axial piston pump, and instead of spline coupling the rotating shaft of the electric motor and the rotating shaft of the axial piston pump, the axial pressure pump extends on the extension line of the rotating shaft of the motor. A fluid pressure servo pump in which a cylinder block of a piston pump is integrally formed is known (for example, see Patent Document 2).

  Since these devices have a configuration in which the electric motor and the axial piston pump are arranged in the direction of the rotation axis, the length of the entire device in the direction of the rotation axis is set to the length in the direction of the rotation axis of the electric motor and the axial piston. It cannot be shorter than the total length of the pumps in the rotational axis direction.

  On the other hand, it is a pump motor composed of an electric motor and an axial piston pump, and the rotor of the electric motor is press-fitted into the outer peripheral surface of the cylinder block of the axial piston pump (the outer surface in the radial direction of the rotating shaft) There is known a pump motor that rotates integrally with the motor (for example, see Patent Document 3).

JP 2001-317447 A JP 63-0775369 A JP-A-10-103112

  However, in the pump motor described in Patent Document 3, the swash plate of the axial piston pump and the stator of the motor communicate with each other in the housing in order to use the hydraulic oil handled by the axial piston pump for cooling the motor. Since the stator is immersed in the hydraulic oil while being arranged in the space, there is a possibility of causing a short circuit of the stator coil in the electric motor, which is problematic in terms of reliability.

  In view of the above-described points, an object of the present invention is to provide a more reliable fluid pressure generator that can shorten the length of the entire device in the direction of the rotation axis.

  In order to achieve the above object, a fluid pressure generating device according to an embodiment of the present invention is a fluid pressure generating device including an electric motor, an axial piston pump, and a rotating shaft, and the electric motor has a cylindrical shape having a cavity. And a stator surrounding the rotor, the axial piston pump including a swash plate and a cylinder barrel, at least partially disposed in the cavity, the rotating shaft including the electric motor and the axial The piston pump extends along a common rotation axis of the piston pump and rotates together with the cylinder barrel and the rotor, and the swash plate is non-rotatably disposed in the cavity. With this configuration, the fluid pressure generating device according to the embodiment of the present invention can reduce the length of the entire device in the rotation axis direction while preventing the hydraulic oil of the axial piston pump from reaching the stator of the electric motor. .

  The stator is preferably liquid-tightly isolated from the axial piston pump by an oil seal disposed in contact with the rotor. With this configuration, the fluid pressure generating apparatus according to the embodiment of the present invention can further reliably prevent the hydraulic oil of the axial piston pump from reaching the stator of the electric motor.

  The cylinder barrel preferably exposes a surface on the opposite side of the surface facing the swash plate from the cavity. With this configuration, the fluid pressure generating device according to the embodiment of the present invention reduces the length of the pipe between the axial piston pump and the fluid pressure circuit or the fluid tank while realizing the above-described effect. Further simplification can be realized.

  By the above-mentioned means, the present invention can provide a more reliable fluid pressure generating device capable of shortening the length in the rotation axis direction of the entire device.

It is a perspective view which shows the structural example of the fluid pressure generator which concerns on the Example of this invention. It is a cross-sectional perspective view of the fluid pressure generator of FIG. It is a schematic sectional drawing (the 1) of the fluid pressure generator of FIG. FIG. 3 is a schematic cross-sectional view (part 2) of the fluid pressure generating device of FIG. 1. FIG. 3 is a schematic cross-sectional view (part 3) of the fluid pressure generating device of FIG. 1. FIG. 4 is a schematic cross-sectional view (part 4) of the fluid pressure generating device of FIG. 1.

  Hereinafter, the best mode for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 is a perspective view showing a configuration example 100 of a fluid pressure generating device according to an embodiment of the present invention, FIG. 2 is a sectional perspective view thereof, and FIGS. 3 to 6 are schematic sectional views thereof. 3 to 6, members whose cross-sections are indicated by hatching with fine meshes represent rotatable members, and members whose cross-sections are indicated by hatching with rough eyes represent non-rotatable members. Shall.

  The fluid pressure generating device 100 is, for example, a pipe by discharging a working fluid (for example, hydraulic oil) sucked from a fluid tank 60 (for example, an oil tank) to the pipes 70 and 71 at a desired flow rate. A device for generating a desired fluid pressure in a fluid pressure circuit (not shown) to which 70 and 71 are connected. Mainly, the housing 10, the electric motor 20, the axial piston pump 30, the rotary shaft 40, and the rotation The detection unit 50 is configured.

  The housing 10 is a member for supporting the electric motor 20, the axial piston pump 30, and the rotary shaft 40 while maintaining a predetermined relative positional relationship among the electric motor 20, the axial piston pump 30, and the rotary shaft 40. For example, the axial member 11 extending along the axial direction of the rotating shaft 40, the first lid member 12 disposed on the end surface of the axial member 11 on the side where the rotation detecting unit 50 is installed, and the axial piston pump 30 Includes a second lid member 13 disposed on the end surface of the axial member 11 on the side of sucking and discharging the hydraulic oil.

  The axial member 11 is a cylindrical member having a cavity for accommodating the electric motor 20 and the axial piston pump 30 therein, a first lid member 12 is coupled to one end thereof, and a second lid member is coupled to the other end thereof. 13 are combined. Further, the axial member 11 has a conductor opening 110 for guiding a conductor (not shown) connected to the electric motor 20 accommodated therein to the interior thereof.

  The first lid member 12 is a member including a plate-like substrate portion 120 and an extension portion 121 extending from the substrate portion 120 along the rotary shaft 40.

  In the present embodiment, the first lid member 12 is formed with a through hole for allowing the rotary shaft 40 to pass through the substrate part 120 and the extension part 121. The first lid member 12 includes the substrate portion 120 and the extension portion 121 that are individually formed, but may include the substrate portion 120 and the extension portion 121 that are integrally formed.

  In addition, the rotation detector 50 attached to the outer surface of the first lid member 12 (the surface on the side opposite to the side to which the axial member 11 is coupled) rotates the rotating shaft 40. Although it has a through hole for allowing the rotation shaft 40 to pass therethrough so that the rotation detection unit 50 can be connected to the rotation shaft 40, the rotation detection unit 50 is attached to the inner surface of the first lid member 12. When embedded in the first lid member 12, a through hole for allowing the rotary shaft 40 to pass therethrough can be omitted.

  The second lid member 13 is a member having a plate-like substrate portion 130, and in this embodiment, the substrate portion 130 is a rotor 22 (details will be described later) of the electric motor 20 and a cylinder barrel 32 of the axial piston pump 30. (Details will be described later) and a through hole for allowing the rotary shaft 40 to pass therethrough is exposed.

  The outer surface of the second lid member 13 (the surface on the side opposite to the side to which the axial member 11 is coupled) is coupled to the port plate 132 via the O-ring 131.

  The port plate 132 is a plate-like member that is installed between the fluid pressure generating device 100 and the oil tank 60, and is a first port 133 that communicates between the oil tank 60 and the axial piston pump 30 (the cross section in FIG. 3). The second port 134 communicates the axial piston pump 30 and the pipe 70, and the third port communicates the pipe 71 and the axial piston pump 30 (not shown). ) In the interior thereof.

  In the present embodiment, the second lid member 13 is provided as a separate member independent of the port plate 132, and when the port plate 132 is removed from the second lid member 13, the rotor 22 of the electric motor 20 and the axial piston pump 30 Although the maintainability is improved by adopting a configuration in which the cylinder barrel 32 is exposed, it may be provided as a member formed integrally with the port plate 132. In addition, the rotating shaft 40 penetrating the second lid member 13 is supported at the port plate 132 via the bearing 41.

  The electric motor 20 is a device that rotates by receiving electric power supplied from an external power source (not shown). Preferably, a closed-loop control servomotor is used, but a three-phase induction motor is also used. Good. In addition, the magnitude and direction of power supplied from an external power source are controlled by an external controller (not shown).

  In this embodiment, the electric motor 20 includes a cylindrical stator 21 fixedly attached to an inner wall of a cavity formed inside the axial member 11, and a bearing 125 at the first lid member 12 and the second lid member 13. And a cylindrical rotor 22 that is rotatably supported via each of the bearings 135. The rotor 22 is rotatably supported by another bearing at the axial member 11 instead of at least one of the bearings 125 and 135 at the first lid member 12 and the second lid member 13. May be.

  Further, the fluid pressure generator 100 includes oil seals 126, 136 between the extension 121 of the first lid member 12 and the rotor 22 and between the seal support portion 137 of the second lid member 13 and the rotor 22, respectively. The hydraulic oil of the axial piston pump 30 is prevented from reaching the stator 21 of the electric motor 20.

  In addition, the electric motor 20 has a magnetic field generated by flowing a current supplied from an external power source through the coil 210 of the stator 21 and an outer wall of the rotor 22 facing the stator 21 in the radial direction of the rotating shaft (outside of the rotating shaft in the radial direction). The rotor 22 is rotated using a magnetic field generated by a permanent magnet (not shown) installed on the surface of the substrate.

  The rotor 22 has a cavity for accommodating at least a part of the axial piston pump 30 in the inside thereof, so that the length of the fluid pressure generating device 100 in the rotation axis direction can be shortened. Preferably, the rotor 22 houses the entirety of the axial piston pump 30 therein (specifically, as shown in FIG. 3, the right end surface of the rotor 22 and the right end surface of the axial piston pump 30) So that the length of the axial piston pump 30 in the direction of the rotation axis does not become a decisive factor in determining the length of the fluid pressure generator 100 in the direction of the rotation axis (ie, fluid (The length of the pressure generator 100 in the direction of the rotation axis is mainly determined by the length of the rotor 22 in the direction of the rotation axis.)

  The axial piston pump 30 mainly includes a swash plate 31 and a cylinder barrel 32. The swash plate 31 is supported so as not to rotate, and the cylinder barrel 32 is supported so as to be rotatable.

  With this configuration, the axial piston pump 30 moves the piston shoe group 34 connected to the piston group slidable in the cylinder barrel 32 so as to draw a circle on the inclined surface of the swash plate 31, and each of the piston groups. By reciprocating the inside of the corresponding cylinder formed in the cylinder barrel 32, for example, as shown in FIG. 3, the piston 33A that is currently in the expansion stroke (the invisible part because it does not constitute a cross section in FIG. 3). The same applies to the opening 35A and the first port 133.) The hydraulic oil is drawn into the cylinder from the oil tank 60 through the first port 133 and the opening 35A of the port plate 132. (Note that the piston group is connected to the third port of the port plate 132 and the respective The hydraulic oil is sucked into the cylinder from the pipe 71 through the opening.) The piston 33 currently in the compression stroke supplies the hydraulic oil in the cylinder through the opening 35 and the second port 134 of the port plate 132 to the pipe 70. Discharge toward

  In this embodiment, the axial piston pump 30 has an odd number (for example, nine) of cylinder groups in the cylinder barrel 32, and a corresponding number of piston groups are disposed inside the odd number of cylinder groups. Although it reciprocates, it may have an even number of cylinder groups.

  Further, in this embodiment, the axial piston pump 30 is completely accommodated in a cylindrical cavity formed in the rotor 22 of the electric motor 20, but the cylinder barrel 32 is accommodated while the swash plate 31 is accommodated in the cavity. A part may be protruded outside the cavity.

  The swash plate 31 is fixedly coupled to the end surface of the extension portion 121 of the first lid member 12 extending from the substrate portion 120 of the first lid member 12 into the cavity formed in the rotor 22 of the electric motor 20 along the rotary shaft 40. In addition, a through hole for allowing the rotary shaft 40 to pass therethrough is provided at the center thereof.

  In this embodiment, the swash plate 31 has a cylindrical shape, and is fixed to the end surface of the extension portion 121 via a flat surface on the opposite side of the inclined surface in a state where the inclined angle of the inclined surface in the axial direction is fixed. Although fixedly coupled, it may be installed such that its tilt angle is variable by a known tilt angle variable mechanism.

  On the other hand, the cylinder barrel 32 is coupled with the outer wall (the surface on the radially outer side of the rotating shaft) and the inner wall of the rotor 22 (the surface on the radially inner side of the rotating shaft) by key coupling or spline coupling, and rotates together with the rotor 22. Configured to be possible.

  Further, the cylinder barrel 32 has a through hole for passing through the rotary shaft 40 at the center, and the inner wall of the through hole and the outer wall of the rotary shaft 40 are coupled by key coupling, spline coupling, or the like. 40 is configured to be rotatable together.

  In this embodiment, the cylinder barrel 32 is a port plate in which the surface opposite to the surface facing the swash plate 31 in the axial direction (surface on the side where the opening 35 is disposed) is exposed from the cavity formed in the rotor 22. 132 and face each other.

  Compared with the case where the arrangement of the swash plate 31 and the cylinder barrel 32 is reversed as shown in FIG. 4 (that is, the surface of the cylinder barrel 32 opposite to the surface facing the swash plate 31 in the axial direction (the opening 35 is The surface of the swash plate 31 facing the end surface of the extension 121 of the first lid member 12, and the flat surface on the opposite side of the inclined surface of the swash plate 31 is exposed from the cavity formed in the rotor 22. This is because the structure of the fluid pressure generating device 100 can be simplified as compared with the case where it is coupled to the plate 132 (the structure shown in FIG. 4 is for guiding the hydraulic oil sucked or discharged by the axial piston pump 30). It is necessary to form the piping inside the first lid member 12 so as to bypass the rotation detection unit 50). However, the fluid pressure generator 100 does not exclude the structure shown in FIG.

  The rotation shaft 40 is a shaft extending along a common rotation axis of the electric motor 20 and the axial piston pump 30 and is a shaft for smoothly rotating the rotor 22 of the electric motor 20 and the cylinder barrel 32 of the axial piston pump 30. .

  In the present embodiment, the rotary shaft 40 has one end penetrating the first lid member 12 and rotatably supported through the bearing 42 at the first lid member 12, and the other end penetrating the axial piston pump 30. It is supported at the port plate 132 through a bearing 41 so as to be rotatable.

  Further, an oil seal 43 is installed between the seal support portion 44 of the first lid member 12 and the rotary shaft 40 to prevent the hydraulic oil of the axial piston pump 30 from reaching the rotation detection portion 50.

  In addition, the rotation shaft 40 is connected to the rotation detection unit 50 at one end thereof, so that the rotation detection unit 50 can detect the rotation speed of the rotation shaft 40 and consequently the rotation speed of the axial piston pump 30 and the rotation speed of the electric motor 20. To do.

  The rotation detection unit 50 is a device for detecting the rotation of the rotation shaft 40. For example, the rotation detection unit 50 is an encoder, a potentiometer, or a resolver arranged around the axis of the rotation shaft 40. It is a controller for controlling the power supplied to 20). This is because the rotational speed of the rotor 22 in the electric motor 20 can be feedback controlled.

  In the present embodiment, the rotation detection unit 50 is attached to the outer surface of the first lid member 12 (the surface on the side opposite to the side to which the axial member 11 is coupled). It may be attached to the inner surface of the first lid member 12 or may be embedded in the first lid member 12.

  Note that the rotation detection unit 50 may be omitted when the open-loop control electric motor 20 is used because it is not necessary to know the rotation speed of the electric motor 20.

  With the above configuration, when the current is supplied to the coil 210 of the stator 21 in the electric motor 20 and the rotor 22 is rotated, the fluid pressure generator 100 of the axial piston pump 30 coupled to the inner wall of the cavity in the rotor 22 is provided. The cylinder barrel 32 and the rotary shaft 40 coupled to the inner wall of the through hole in the cylinder barrel 32 are rotated together, and the oblique piston pump 30 is fixedly attached to the end surface of the extension 121 of the first lid member 12. By rotating the cylinder barrel 32 with respect to the plate 31, the hydraulic oil sucked into the cylinder from the oil tank 60 through the opening corresponding to each of the piston groups reciprocatingly moved in each of the cylinder groups formed inside the cylinder barrel 32. The pipe 70 (the rotation direction of the cylinder barrel 32 is In this case, the hydraulic oil is discharged into the pipe 71.), and the hydraulic oil sucked into the cylinder from the pipe 71 (the pipe 70 when the rotation direction of the cylinder barrel 32 is reversed) through these openings is The oil tank 60 can be discharged through these openings.

  Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the above-described embodiments, and various modifications and substitutions can be made to the above-described embodiments without departing from the scope of the present invention. Can be added.

  For example, in the above-described embodiment, the fluid pressure generating device 100 fixedly attaches the swash plate 31 of the axial piston pump 30 to the end surface of the extension portion 121 of the first lid member 12, as shown in FIG. The flat surface on the opposite side of the inclined surface of the swash plate 31 may be exposed from the cavity formed in the rotor 22 and fixedly attached to the substrate portion 120 of the first lid member 12.

  In this case, the cylinder barrel 32 of the axial piston pump 30 extends in a cavity formed in the rotor 22 on the surface opposite to the surface facing the swash plate 31 in the axial direction (the surface on which the opening is disposed). The port plate 132 is disposed so as to face the end surface of the extension 137. Further, the port plate 132 extends the first port 133, the second port 134, and the third port (not shown) inside the port plate 132 over the entire length of the extension portion 137.

  Further, as shown in FIG. 6, the fluid pressure generating device 100 is configured to fix the swash plate 31 to the end surface of the extension portion 121 of the first lid member 12 extending into the cavity formed in the rotor 22. However, the cylinder barrel 32 may face the end surface of the extension 137 of the port plate 132 extending into the cavity formed in the rotor 22.

  DESCRIPTION OF SYMBOLS 10 ... Housing 11 ... Axial member 12 ... 1st cover member 13 ... 2nd cover member 20 ... Electric motor 21 ... Stator 22 ... Rotor 30 ... Axial piston pump 31 ... Swash plate 32 ... Cylinder barrel 33, 33A ... Piston 34 ... Piston shoe 35, 35A ... Opening 40 ... Rotating shaft 41 ... Bearing 42 ... Bearing 43 .... Oil seal 44 ... Seal support part 50 ... Rotation detection part 60 ... Oil tank 70, 71 ... Piping 100 ... Fluid pressure generator 110 ... Lead wire port 120 ... Substrate Part 121: Extension part 125 ... Bearing 126 ... Oil seal 130 ... Substrate part 131 ... O-ring 132 ... Port plate 133 ... First port 134 ... second port 135 ... bearing 136 ... oil seal 137 ... seal support 210 ... coil

Claims (3)

A fluid pressure generator including an electric motor, an axial piston pump, and a rotating shaft,
The electric motor includes a cylindrical rotor having a cavity, and a stator surrounding the rotor,
The axial piston pump includes a swash plate and a cylinder barrel, and is at least partially disposed within the cavity;
The rotating shaft extends along a common rotating shaft of the electric motor and the axial piston pump, and rotates together with the cylinder barrel and the rotor,
The swash plate is non-rotatably disposed in the cavity;
A fluid pressure generator characterized by that. The stator is liquid-tightly isolated from the axial piston pump by an oil seal disposed in contact with the rotor;
The fluid pressure generator according to claim 1. The cylinder barrel exposes a surface opposite the surface facing the swash plate from the cavity;
The fluid pressure generator according to claim 1, wherein the fluid pressure generator is provided.

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