JPH01244363A - Centrifugal soil testing apparatus - Google Patents

Abstract

PURPOSE:To make a hydraulic actuator compact and light, by arranging a hydraulic unit around a driving shaft so that the unit is rotated together with said shaft, and using the oil pressure supplied to the hydraulic actuator at a high pressure. CONSTITUTION:A hydraulic unit 16 is arranged around a driving shaft so that the unit is balanced in weight and rotated freely together with said shaft. Low pressure oil which is supplied through an external pipe 15a and a hydraulic rotary coupling 11 is supplied into a tank 16a in the hydraulic unit 16 through a pipe 15b. The low pressure oil is said tank 16a is sent into a hydraulic pump 16b in testing. The pressure of the oil is increased to high pressure. The oil is appropriately supplied into a hydraulic actuator 17 through a pipe 15c. The actuator 17 performs the work for a bucket 3 or a body under test 14. The oil after the working is returned into the tank 16a through a pipe 15d.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a centrifugal force type soil testing device 1 that can perform soil testing while applying centrifugal force to soil.

[Conventional technology]

When designing and constructing the foundations of structures, dams, roads, etc. that are made of soil, it is very important to know the properties of soil, and therefore chemical tests, physical tests, strength tests, etc. Various tests are conducted depending on the purpose. The centrifugal force type soil testing device that is the subject of this article applies centrifugal force to the soil, which increases the apparent weight of the soil, reproduces the actual condition in the laboratory, and performs various tests. It is what was done.

For example, the foundation (soil) of the above structure is under pressure commensurate with the weight of the structure and the own weight of the soil, so
When you want to investigate the properties of a foundation that is exposed to soil, you can arbitrarily adjust the centrifugal force applied to the test piece to reproduce the pressure state in actual soil, and conduct the investigation in the laboratory.

A conventional centrifugal force type soil testing device is shown in FIGS. 3 and 4.

In the figure, reference numeral 1 denotes a drive shaft, which is rotatably fitted and supported by a main bearing 5 supported by a foundation 9. An arm 2 is fixedly attached to the main bearing 5 at its center, and a packet 3 (3') is rotatably attached to the front end of the arm 2 via a hinge 18. Packet 3 is a sample box 4 (4') that stores the soil or structural model to be tested.
). A power transmission device 6 is installed at the bottom of the drive shaft 1 and transmits the rotation of the motor 7 to the drive shaft 1 via the transmission shaft 8 to provide the required rotation.

A rotary hydraulic joint 11 is attached to the upper end of the drive shaft, and serves to transmit the hydraulic pressure sent from the external hydraulic piping 15 (or 15') to the piping inside the rotating shaft 1.
In the illustrated example, a desired test load is applied to the test specimen 14 by supplying hydraulic pressure to the hydraulic jack 13.

Further, an electrical slip ring 12 is installed at the lower end of the drive shaft, so that input/output signals obtained by electrically converting the test load or stress/displacement received by the test object can be taken out to the outside.

The entire device is shielded from the outside by a protective wall 10 to ensure safety against accidental damage.

In addition, one set of packets 3 and 3' can be set at the top of the image of arm (■), so two sets of specimens can be tested at the same time, but if you want to test only one set, you can place the counter in the other set of sample boxes. Attach weights to maintain balance during rotation.

Before the drive shaft 1 rotates (before the test), the packet 3 hangs down as shown by the dotted line in the figure (the same applies to the sample box). The motor is driven and the drive shaft 1 is connected via the power transmission device.
When the packet 3 begins to rotate, the packet 3 receives a centrifugal force and begins to rotate again while maintaining a horizontal state, and a predetermined centrifugal force acts on the test specimen 14 in the sample box 4, so that the test specimen 14 in that state Various tests are carried out on 14.

(Problem to be Solved by the Invention) In FIG. 3, a desired test load is applied to the test specimen 14. Pressure oil is supplied to the hydraulic jack 13 via the rotary hydraulic joint 11. In this case Figure 118 of hydraulic joint 11
Since the part 11b is structurally destined to be fixed to the foundation 9 and rotate together with the drive shaft 1, only low-pressure oil can be supplied to the hydraulic jack. When low pressure is used, the equipment (jacket) is larger than when high pressure is used to obtain the same test load (output).

However, in the case of this test device, reducing the rotating weight improves performance.
It is also advantageous to save power, so the equipment installed on the arm 2 needs to be as light and compact as possible, and there is a strong demand for the hydraulic equipment to use high-pressure oil.

The present invention aims to solve the above problems.

[Means to solve the problem]

A hydraulic unit type is arranged in a balanced manner around the drive shaft and configured to rotate together with the drive shaft. The low pressure oil supplied from the external piping via the rotary joint (or directly to the hydraulic unit) is increased in pressure by the hydraulic unit and then supplied to the hydraulic actuator as high pressure oil.

[For production]

The above configuration enables high pressure oil to be supplied to the hydraulic actuator.

【Example〕

An embodiment of the present invention is shown in FIGS. 1 and 2.

In the figure, reference numeral 11 denotes a rotary hydraulic joint which has the function of transferring hydraulic pressure from a stationary part to a rotating part (or vice versa). 11a is the part of the same joint that is fixed to the foundation 9, 11b is the same (the part that rotates with the drive shaft, 16 is a hydraulic unit arranged so that it is weight balanced around the drive shaft, and rotatable together with the same shaft) 16 a is the tank part,
16b shows the hydraulic pump part. Further, a hydraulic actuator 17 is attached to the inner wall of the packet 3, and is configured to apply desired manual force to the sample box 4 (or test specimen). In addition, 15 a is external hydraulic piping, 15 b
~15d shows the hydraulic piping inside the device.

Note that the hydraulic rotary joint may not be provided, and low-pressure oil may be directly supplied to and drained from the hydraulic unit by a separate means from the outside.

In this device, low pressure oil is supplied from the external pipe 15a via the hydraulic rotary joint 11 (or directly by a separate means without using the joint 11) and is supplied to the tank in the hydraulic unit 16 via the pipe 15b (or directly). 16a. During the test, the low-pressure oil in the tank is sent to the hydraulic pump 16b, raised to high pressure, and then sent to the hydraulic actuator 1 from the piping 15C.
7, and the actuator 17 receives the packet 3.
Alternatively, the test specimen 14 will be subjected to treatment. After finishing the treatment, the drained oil returns to the tank 16a via the pipe 15d.

The hydraulic pressure used in this case is P+ ”” 210Ky/cmz
or more are commonly used. In the case of the conventional method of directly supplying the rotary joint to the hydraulic actuator, the limit is P2 = 70 to 140 Kf/cmz, so when comparing the two, for example, the output is 30 TON.
The actuator diameter d required to obtain P is ds; 13.5mφP when L=210KV/Cm.
When 2=140 # d * # l 5
When country φpz = 70 #, d ≠ 23 φ, and if a genuine material that can be used at high pressure is used, the actuator can be made smaller and lighter, which in turn leads to improved performance of the test equipment.

〔Effect of the invention〕

By arranging the hydraulic unit around the drive shaft so that it rotates along with the same shaft, the hydraulic pressure supplied to the hydraulic actuator can be used at high pressure.1) The hydraulic actuator can be made smaller and lighter.2-) The piping and pulp can be made smaller. 3) Reducing the size and weight of the device configuration leads to improved performance of the test device.

[Brief explanation of the drawing]

FIG. 1 is a side view showing one embodiment of the present invention, and FIG. 2 is a side view showing one embodiment of the present invention.
Fig. 3 is a side view showing the concept of a conventional centrifugal soil testing device, and Fig. 4 is a plan view thereof. 1... Drive shaft, 2... Arm, 3.3'... Packet, 4.4'... Sample box, 5... Main bearing, 6...
・Power transmission device, 7...Motor, 8...Transmission shaft, 9
．． 9'... Foundation, 10... Protective wall, 11... Rotating hydraulic joint, 12... Electrical slip ring, 13...
・For loading, oil, pressure jack, 14...Test specimen, 15.
15'... Hydraulic piping, 18... Hinge, 17...
Hydraulic actuator, 16...hydraulic unit.

Claims (1)

[Claims] A drive shaft that is supported by a set of bearings and rotates in an upright state, a pair of left and right arms that are fitted and fixed to the drive shaft, and a pair of packets that are rotatably connected to the tips of the arms.
A sample box placed on the same packet and containing soil or other test object as a test object therein, an actuator that applies a test load to the sample box or the test object, and an actuator arranged around the drive shaft. A centrifugal force soil testing device comprising: a fluid pressure unit that is installed to rotate together with the drive shaft and supplies pressure fluid to the actuator.