JPS61294201A - Hydraulic unit - Google Patents

Abstract

PURPOSE:To contrive to reduce a noise together with to contrive to miniaturize a hydraulic unit by arranging a hydraulic pump and its driving motor inside the inner cylinder of an accumulator. CONSTITUTION:A hydraulic pump 11 and its driving motor 12 is arranged lengthwise inside the inner cylinder 2 of a hydraulic unit and an oil passage 10 connecting the discharging port of the oil pump 11 to an accumulator oil chamber 6 is formed in the end plate of a cylinder base part. Between an outer cylinder 1 and an inner cylinder 2 is arranged a ring-shaped piston 4 to form an accumulator using an reaction force in a gas chamber 5. The hydraulic pump 11 and its driving motor 12 are arranged inside the inner cylinder 2 of the hydraulic unit. Hereby the hydraulic unit can be made in a small-sized and compact from the furthermore the oil chamber 6 and the gas chamber 5 are serving as a shock absorbing chamber, therefore a noise from a hydraulic pump and a driving motor is not directly transmitted to the air.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a hydraulic unit that supplies high-pressure hydraulic oil to hydraulic equipment such as a hydraulic actuator.

Conventional technology A conventional hydraulic unit is, for example, disclosed in U.S. Pat.
As shown in the publication, the structure was as shown in FIGS. 2 and 3. That is, the hydraulic oil flowing from the suction port 16 is pressurized into a block 18 that has a suction port 16, a discharge port 16, and a passage 17 that communicates these ports, and then flows into the discharge port 16 through the passage 17. A hydraulic pump 19 to be supplied is housed, and a motor 20 for driving the hydraulic pump 19 is disposed in the block 18 to form a hydraulic circuit, and a safety valve 21 is activated when the hydraulic pressure of the hydraulic circuit exceeds a predetermined pressure. , stores the pressure oil in the hydraulic circuit, compensates for instantaneous flow shortages and pressure drops due to insufficient capacity of the hydraulic pump, prevents deterioration of responsiveness, absorbs pulsation of the hydraulic pump, and smoothes pressure fluctuations. and an accumulator 22 in the passage 17.
It has a structure in which it is connected to a predetermined location of the block 18 and fixed to the block 18.

Problems to be solved by the invention - However, in a hydraulic unit with such a structure, the motor 2
0 and the accumulator 22 are arranged side by side, there is a limit to weight reduction, and the maximum width of the hydraulic unit (W in Fig. 2) is the width of the motor 2 degrees and the accumulator 22.
It cannot be made shorter than the sum of the widths of . Therefore, for example, when storing a hydraulic unit as a drive source of a hydraulically driven industrial robot inside the arm of the industrial robot, there is a problem that the weight of the arm increases and the diameter of the storage space increases. was there. Furthermore, since the hydraulic pump 19 and motor 20 are exposed, there is a problem in that the noise is large.

In view of the above problems, the present invention shortens the maximum width of the hydraulic unit, and reduces the arm weight when storing the hydraulic unit as a drive source for an industrial robot driven by hydraulic pressure, for example, inside the arm of the industrial robot. This makes it possible to reduce the weight of the machine, reduce the diameter of the storage space, and reduce noise.

Means for Solving the Problems In order to solve the problems of the conventional hydraulic unit, the present invention arranges an outer cylinder and an inner cylinder that constitute an accumulator substantially coaxially, and is surrounded by the outer cylinder and the inner cylinder. The space is provided with a ring-shaped piston slidably arranged to separate the space into an oil chamber and a gas chamber, and a hydraulic pump and a motor for driving the hydraulic pump are installed inside the inner cylinder. It is arranged approximately coaxially with the inner cylinder.

By placing the hydraulic pump and motor on the side,
The maximum width of the hydraulic unit can be shortened, the number of component parts such as motor covers can be reduced, and the weight can be reduced due to the miniaturization of component parts. At the same time, the noise from the hydraulic pump and motor is not emitted directly into the atmosphere, so for example When storing a hydraulic unit as a drive source for an industrial robot driven by
The storage space can be made smaller in diameter and noise can be reduced.

EXAMPLE An example of the present invention will be described below with reference to FIG. FIG. 1 is a sectional view showing a specific configuration of a hydraulic unit in an embodiment of the present invention.

In FIG. 1, 1 is an outer cylinder, 2 is an inner cylinder located substantially coaxially inside the outer cylinder 1, 3a and 3b are cylinder ends, and the outer cylinder 1, the inner cylinder 2, and the two cylinders are connected to each other. A ring-shaped piston 4 is slidably disposed in a hollow cylindrical space surrounded by the ends 3a and 3b, and divides the hollow cylindrical space into a gas chamber 5 and an oil chamber 6. The pressure inside the gas chamber 5 is controlled by a valve 7.
A predetermined pressure is set by supplying gas through.

Reference numeral 8 denotes a port for supplying and discharging oil to the oil chamber 6, and a hydraulic pump 1 disposed approximately coaxially inside the inner cylinder 2 via an oil passage 1o formed inside the cylinder end 3b.
It is connected to 1. The hydraulic pump 11 is driven by a motor 12 disposed substantially coaxially inside the inner cylinder 2 via a joint 14 .

In FIG. 1, when the motor 12 is operated and the hydraulic pump 11 is rotated, the hydraulic pump 11 sucks hydraulic oil from the suction port 9, compresses it, and discharges high-pressure hydraulic oil into the oil passage 10. .

The high-pressure hydraulic oil discharged into the oil passage 10 flows into the oil chamber 6 through the port 8, pushes up the ring-shaped piston 4, and compresses the gas filled in the gas chamber 6. The ring-shaped piston 4 then moves to a position where the pressure in the gas chamber 5 and the pressure in the oil chamber 6 are balanced. Reference numeral 13 denotes a safety valve, which is activated when the pressure in the oil passage 10 exceeds a predetermined pressure, and communicates the oil passage 1o with the passage leading to the low-pressure suction port 9.
This prevents the pressure inside the oil passage 10 from exceeding a predetermined pressure and prevents the device from being destroyed by high pressure. Here, when the pressure inside the oil passage 10 decreases due to load fluctuations in the hydraulic equipment connected to the port 8, the oil chamber 6
Since the internal pressure is lower than the pressure inside the gas chamber 5, Zuto-elimination fL 訃II-residue pressure 1 nip Fig. 2 Fig. 3 (f; f2+ '/

Claims (1)

[Claims] An outer cylinder, an inner cylinder located substantially coaxially inside the outer cylinder, two cylinder end plates, and slidably arranged in a space surrounded by the outer cylinder, the inner cylinder, and the two cylinder ends. An accumulator is constituted by a ring-shaped piston that separates the space into an oil chamber and a gas chamber, a valve that intervenes to supply gas to the gas chamber, and a port that supplies and discharges oil to and from the oil chamber, and A hydraulic pump that pressurizes hydraulic oil and supplies it to the oil chamber is provided inside the inner cylinder substantially coaxially with the accumulator, and a motor that drives the hydraulic pump substantially coaxially with the accumulator is provided inside the inner cylinder. Hydraulic unit equipped with.