JP4665334B2 - Electric hydraulic pump - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The invention of this application relates to an electric hydraulic pump that drives a rotating shaft of a hydraulic pump by an electric motor.
[0002]
[Prior art]
In a conventional electric hydraulic pump, for example, as described in Japanese Patent Application Laid-Open No. 11-173278, a brushed DC motor and a rotary shaft of the hydraulic pump are connected by a shaft coupling. In this DC motor, the rotor shaft is rotatably supported by a bearing so that it can operate independently. A rotary shaft seal is installed on the outer periphery of the rotary shaft of the hydraulic pump to prevent hydraulic fluid from leaking to the DC motor side. The cooling of the DC motor is based on air cooling.
[0003]
[Problems to be solved by the invention]
However, the presence of brushes, shaft couplings, rotor bearings, and rotary shaft seals increases the weight and size, and the cost is high. In addition, the life of the rotary shaft seal is relatively short, and a predetermined cooling performance is ensured. Therefore, there is a problem that the physique does not grow.
[0004]
An object of the invention of this application is to provide a small, lightweight, low-cost, long-life electric hydraulic pump by making improvements such as using a sensorless brushless DC motor as an electric motor for driving the hydraulic pump. .
[0005]
In the invention of this application, as described in claim 1, a magnet of a sensorless brushless DC motor is coupled to an outer end portion of a rotating shaft rotatably supported by a pump housing of a hydraulic pump, and the sensorless brushless DC A chamber in which the opening end of a bottomed cylindrical resin motor housing molded integrally with the motor core and coil is coupled to the pump housing via a seal member to house the magnet is provided in the motor housing. The hydraulic oil discharged to a discharge chamber formed in the pump housing passes through a gap between the outer periphery of the rotary shaft and the pump housing via an annular groove of the rotary shaft. Formed in the pump housing through a passage formed in the pump housing from the chamber. An electric hydraulic pump, wherein the sensorless brushless DC motor is cooled by refluxing the suction chamber.
[0006]
This electric hydraulic pump has no brush, no sensor for detecting the position of the magnetic pole, no seal for the rotary shaft of the hydraulic pump, no bearing for the rotary shaft of the motor, and further a sensorless brushless DC motor by hydraulic oil. Since it is cooled, it can be made small, light, low cost, and long life as a whole.
[0007]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a cross-sectional view of an electric hydraulic pump 10 according to an embodiment of the invention of this application. In FIG. 1, the hydraulic pump 11 is formed by a trochoid pump, and the electric motor 12 is formed by a sensorless brushless DC motor.
[0008]
The hydraulic pump 11, that is, the trochoid pump 11, includes a pump housing 11d formed by connecting a body 11a and a cover 11b with an annular seal member 11c interposed therebetween, and a rotating shaft 11e rotatably supported by the pump housing 11d. The inner rotor 11f with external teeth that is rotationally connected to the inner end of the rotating shaft 11e and the outer rotor 11g that has internal teeth that mesh with the external teeth of the inner rotor 11f are the main constituent members. A suction port 11h and a discharge port 11i are formed in the cover 11b. Further, in the body 11a, a suction chamber 11j and a discharge chamber 11k adjacent to one side in the axial direction of the rotors 11f and 11g are formed by the body 11a and the rotors 11f and 11g.
[0009]
The electric motor 12, that is, the sensorless brushless DC motor 12, includes a magnet (permanent magnet) 12a, a core 12b, a coil 12c, a terminal 12d, a core 12b, a coil 12c, and a terminal coupled to the outer end of the rotating shaft 11e. A bottomed cylindrical resin motor housing 12e molded integrally with 12d is a main constituent member. The opening end of the motor housing 12e is coupled to the pump housing 11d by a screw 14 with an annular seal member 13 interposed therebetween, and a chamber 15 for accommodating the magnet 12a is formed inside the motor housing 12e. When the coil 12c is energized by a sensorless driver (not shown) connected to the terminal 12d and a rotating magnetic field is applied to the magnet 12a, a torque is applied to the rotating shaft 11e to which the magnet 12a is coupled to drive the rotating shaft 11e. The trochoid pump 11 is pumped.
[0010]
The chamber 15 communicates with the suction chamber 11j through a passage 16 formed in the body 11a. The body 11a is formed with a passage 17 that communicates the annular groove 11m formed on the outer periphery of the rotating shaft 11e and the discharge chamber 11k. When the trochoid pump 11 is pumping, the body 11a is discharged into the discharge chamber 11k. Part of the hydraulic oil thus passed sequentially passes through the gap between the passage 17-the annular groove 11m-the outer periphery of the rotating shaft 11e and the body 11a and flows into the chamber 15, and absorbs heat by contact with the core 12b to pass through the passage 16. It passes through and returns to the suction chamber 11j. That is, the motor 12 is cooled by the hydraulic oil. The hydraulic fluid supplied from the discharge chamber 11k to the annular groove 11m through the passage 17 also lubricates the outer peripheral sliding portion of the rotating shaft 11e.
[0011]
The pump that forms the hydraulic pump 11 is not limited to the trochoid pump, and may be formed by a gear pump, for example.
[0012]
【The invention's effect】
As described above, the electric hydraulic pump according to the invention of this application has no brush, no sensor for detecting the magnetic pole position, no seal for the rotary shaft of the hydraulic pump, and a bearing for the rotary shaft of the motor. Furthermore, since the sensorless brushless DC motor is cooled by the hydraulic oil, the overall size can be reduced in size, weight, cost, and life.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of an electric hydraulic pump according to an embodiment of the invention of this application.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Electric hydraulic pump 11 ... Trochoid pump 11d which is a hydraulic pump ... Pump housing 11e ... Rotary shaft 11j ... Suction chamber 11k ... Discharge chamber 12 ... Electric motor Sensorless brushless DC motor 12a ... magnet 12b ... core 12c ... coil 12e ... motor housing 13 ... seal member 15 ... chamber 16 ... passage 17 ... passage

Claims (1)

A bottomed cylinder in which a magnet of a sensorless brushless DC motor is coupled to an outer end of a rotating shaft rotatably supported by a pump housing of a hydraulic pump, and is molded integrally with a core and a coil of the sensorless brushless DC motor A chamber for housing the magnet is formed by connecting an opening end of a resin-shaped motor housing with the pump housing via a seal member, and the chamber is formed in the pump housing. The hydraulic oil discharged to the discharge chamber flows into the chamber through the annular groove of the rotating shaft and through the gap between the outer periphery of the rotating shaft and the pump housing, and is formed from the chamber to the pump housing. The sensorless by returning to a suction chamber formed in the pump housing through a closed passage. Electric hydraulic pump, characterized in that Rashiresu DC motor is cooled.

Images