JPS59145377A - Servo pump - Google Patents

Abstract

PURPOSE:To make a pump in whole construction light in weight and in a small size by accommodating both the motor and pump body in the same casing and by allowing a single shaft to serve as both motor and pump shafts. CONSTITUTION:Shafts of a high-frequency motor 3 and a pump body 4 both accommodated in a casing 1 are solidified to form a single shaft 2. The ends of this shaft 2 are borne by bearings 9a, 9b, while the middle part by an intermediate bearing 9C installed between the motor 3 and pump body 4. Another bearing 10b is installed at the opening 1a formed in casing 1, and an end plate 11 is mounted there. Thus the pump in whole construction is made in small size and light in weight.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Application of the Invention] The present invention relates to a servo pump used in an industrial robot.

[Prior art]

In recent years, in order to save energy, actuators such as hydraulic cylinders or hydraulic motors are often driven by variable displacement pumps, so-called servo pumps.

In this case, if the servo pump is placed as close to the actuator as possible, the effect of the pipe system can be reduced.

However, in the past, the main reason why it was difficult to bring the servo pump close to the actuator was that the servo pump itself was too large.

Therefore, as a means of making the servo pump more compact, it has been proposed to rotate the motor using high frequency to make the motor frame smaller, and also to make the pump itself smaller. For example, set the power frequency to 200H2 or 400
Rotating a servo pump in H2 has already been implemented in aircraft where the main goal is to reduce weight.

However, in the past, the motor and pump were manufactured separately and combined using compression rings, which not only made it impossible to reduce the size below a certain limit, but also caused problems with sealing mechanisms such as oil seals. It had the disadvantage of requiring

[Purpose of the invention]

The present invention solves the above problems, shortens the shaft length, and
[Summary of the Invention] In order to achieve the above object, the present invention uses a variable displacement pump driven via a high-speed motor to control the amount of oil and to reduce the size of the actuator. In the servo pump configured to control the motor and the pump body, the motor and the pump body are housed in the same casing, the motor shaft and the pump shaft are made into a single shaft, and this shaft is provided at both ends of the end bearing and the aforementioned The motor is supported by three intermediate bearings installed between the motor and the pump body, and the motor is cooled by drain oil from the pump.

[Embodiments of the invention]

2 is a shaft that integrates the shafts of the high-frequency dark 3 housed in the casing IQ and the pump body 4, and the motor 3 has a rotor 3a attached to the shaft 2 and a casing with an opening. The stator 3b is attached to the inner wall of the stator 1.

The pump body 4 also includes a plurality of cylindrical rotors that rotate by meshing with splines 5 provided on the shaft 2.
482 and the rotors 4a+ + 4ax are respectively slidably housed, and the spherical parts 4C1,
The pistons 4b1 and 4b each have a diameter of 4C2. Reference numeral 6 denotes a 7-plate which is swung by the control valve 9 using a guide 8 attached to the shaft 2 as a guide.A piston shoe 7 having an annular groove 7atl is fixed to this shoe tray. The ball portion 4c1°4cl is slidably fitted into #17a.

The shaft 2 has both ends supported by end bearings 9a and 9b, and an intermediate portion between the motor 3 and the pump body 4.
It is supported by an intermediate bearing 9c provided between. Further, the end bearing 10 is provided in the opening 1a of the casing 1.
b, and the arc-shaped oil passage 1 as shown in Fig. 3.
An end plate 11 having oil passages 11a and 11 having oil passages 11a and 11b is opened on one side facing the cylindrical rotor 4ats4ai, and communicated with the actuator 12 on the other side. It is connected to the oil tank 13 via.

Next, the operation of this embodiment having the above configuration will be explained.

First, the 7 U plate 6 and the piston shoe 7 are held in an inclined state in the upper right hand side as shown in FIG. Through rotor 4 a i * 4
As at rotates, the pistons 4b, , in its rotor rotate.
4b is also rotated in the same way, and at the same time the ball portion 4Cxs4c2 at its tip moves along the annular groove 7a of the screw P shoe 7, so that the left row of the piston 4b and the right row of the piston 4b repeat every half rotation. Do it. Therefore, the hydraulic oil that has flowed into the rotor 4aly4al via the shuttle valve 14 passes through the oil passage 11a to the piston 12a of the actuator 12.
Since the hydraulic oil in the left chamber of the piston 12a flows into the right chamber of the piston 12a and moves it to the right, the hydraulic oil flows into the shoe plate 11.
oil tank 1 via oil passage 11b and shuttle valve 14.
Returned to 3. Move the piston shoe 7 in the opposite direction (
If you tilt it in the upper left direction), it will perform the opposite operation to the above.

On the other hand, the drain leaking from the pump body 4 is transferred to the intermediate bearing 1
0c and into the chamber housing the motor 3, and after cooling the motor 3, the intermediate bearing 10c of the casing example is abolished, and the rotor 4ah4a of the pump body 4 is replaced.
The structure is the same as in FIG. 1 except that a bearing portion 15 is provided on the inner wall of the casing facing toward the outer periphery of FIG. 2, so a description thereof will be omitted.

〔Effect of the invention〕

As explained above, according to the present invention, the axial length of the motor and the pump is shortened by uniaxializing the motor and the pump, and the pump is supported by a minimum number of bearings. It can be made lighter.

Furthermore, by cooling the motor with the drain oil of the pump, the air load of the motor can be increased, the motor itself can be made smaller, and since a sealing mechanism is not required, rotation loss can be reduced.

[Brief explanation of the drawing]

1 and 3 are cross-sectional views showing one embodiment of the servo pump of the present invention, and FIG. 3 is a view taken along the line X--X in FIG. 1...Casing, 2...Shaft, 3...Motor, 4
... Pump body, 10a ~ IOC ... Bearing, 15.
・・Bearing part.

Claims (1)

[Scope of Claims] 1. In a servo pump configured to control an actuator by controlling the amount of oil by a variable displacement pump driven via a high-speed motor, the motor and the pump body are housed in the same casing. At the same time, the motor shaft and pump shaft are integrated into a single shaft, and this shaft is supported by three bearings: an end bearing installed at each end of the shaft, and an intermediate bearing installed between the motor and the pump body. 1. A servo pump, characterized in that the motor is supported by a servo motor, and the motor is cooled by dray oil of the pump. 2. The servo pump according to claim 1, wherein the intermediate bearing is a bearing provided on the inner wall of the casing facing the outer circumference of the rotor of the pump body.