JPH0543394Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a braking torque generating device used for load testing of rotating machines such as engines, and more specifically, proposes a large-capacity device.

[Conventional technology]

This type of braking torque generating device is disclosed in, for example, Japanese Utility Model Application No. 62-46342 filed by the present applicant;
62-123073, and as shown in Fig. 6, a rotating shaft 1 is interlocked and connected to the rotating shaft A of the rotating machine to be tested, and a rotating shaft 1 is arranged coaxially with this in order to apply a braking force to this rotating shaft 1. It is equipped with a hydraulically operated wet type multi-disc brake 2. A housing 3 of this brake 2 is arranged so as to be swingable around the rotating shaft 1.

The housing 3 swings and displaces according to the applied braking torque, but the arm 4 protruding from the housing 3
Connected to the piston 5 of the fixed hydraulic cylinder 6,
The swinging force of the housing 3 or the arm 4 is supported by the pressure oil applied to the hydraulic cylinder 6. Further, a load cell 18 detects the force applied from the arm 4 to the hydraulic cylinder 6, that is, the load equivalent to the braking torque. The hydraulic cylinder 6 further has a valve body actuated by movement of the piston 5, and is configured to control the hydraulic pressure applied to the brake 2 by this valve body. The pressure oil that has passed through the valve (variable orifice) that is opened and closed by this valve body is transferred to the directional control valve 16.
is applied to brake 2 via
An electromagnetic switching valve 16 is provided to return pressure oil from the side to the valve body side (also to prevent brake lock in both forward and reverse rotation directions). The braking torque to be applied is determined by the setting of the hydraulic pressure for the brake 2, and the load equivalent to the braking torque detected by the load cell 18 is used for feedback control.

[The problem that the idea attempts to solve]

By the way, a device that can handle a large rotating machine to be tested requires a pressure oil supply system with a large capacity, but it is difficult to obtain a large capacity for the electromagnetic switching valve 16.

Furthermore, the braking torque is changed as needed to simulate various loads, but in order to improve the response characteristics of the rotating machine accordingly, the braking torque needs to be changed as set. However, even if the set torque is changed, the actual change follows with a delay, or the vibration convergence due to the change is slow, so it is necessary to control the transient characteristics with high precision when changing the braking torque of the rotating machine under test. That was impossible.

The present invention has been made in view of the above problems, and an object thereof is to provide a large-capacity braking torque generator for load testing with excellent transient characteristics.

[Means to solve the problem]

The braking torque generator for load testing according to the present invention includes a hydraulically operated brake that is interlocked with the rotating shaft of a rotating machine to be tested and whose housing is swingable, and a hydraulic cylinder that controls the hydraulic pressure for the brake. A braking torque generating device for load testing includes a double-acting hydraulic cylinder that moves its piston in the direction of braking and releasing the brake, and selectively applying pressure to two oil chambers of the double-acting hydraulic cylinder. It is characterized by comprising a flow rate control type servo valve that supplies oil.

[Effect]

There are large capacity flow control type servo valves.
In addition to being able to handle larger capacity, pressure oil with a flow rate corresponding to the set torque is selectively supplied to the two oil chambers of the double-acting hydraulic cylinder, so the set torque can be quickly obtained, resulting in excellent transient characteristics. can.

〔Example〕

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described in detail below based on drawings showing embodiments thereof.

FIG. 1 is a hydraulic circuit diagram of a braking torque generating device according to the present invention, and FIGS. 2 and 3 are longitudinal sectional views of the brake. The hydraulic pump 50 is rotationally driven by the motor 47, and the pressure oil generated by the hydraulic pump 50 is applied to the brake 2 via a flow rate braking type servo valve 60. The servo valve 60 is a 4-port, 3-position switching type, and in the illustrated position, all ports are closed, the pressure oil generated by the pump 50 is returned to the tank, and the brake 2 is connected to a piston 100 (described later).
is biased by the return spring 102, and the pressure oil inside it is drained through the throttle, so it is released. The spool that excites the solenoids 601 and 602 moves to the side, and an oil flow rate corresponding to the excitation current flows to the oil chamber 10a of the hydraulic cylinder 10 in the brake 2.
Pressure oil is supplied to 10b under increased pressure by the throttle.

Next, the brake 2 and hydraulic cylinder 10 will be explained in detail based on FIGS. 2 and 3. Figure 2 is a cross-sectional view showing the upper half in the brake 2 braking state and the lower half in the brake 2 released state, and the rotating shaft 1 is connected to the rotating shaft of the test target machine (not shown) on the left side of the figure. It rotates together with this. The rotating shaft 1 is supported by bearings 27A and 27B fitted externally on the rotating shaft side of the test target machine, that is, on the left side, and on the opposite side (right side), a swinging shaft 91 is supported with a bearing 27C interposed in a hole formed in the end surface of the rotating shaft 1. , inserted and supported. The bearings 27A, 27B are fitted into the end of the housing 3 of the brake 2, and the housing 3 is swingably supported by the stand 31 and cover (fixed) 30 of the device of the present invention via the bearing 28A. . The swing shaft 91 is connected to the housing 3, and is swingably supported by the cover 30 by a bearing 28B fitted onto the housing 3. The rotary joint 9 is connected to the opening provided on the right shaft end surface of the swing shaft 91 via the bearing 28C.
2 is rotatably fitted. An arm 4 is provided protruding from the housing 3.

The brake 2 is a combination of a rotary plate provided on the rotating shaft 1 side and a brake plate provided on the housing 3 side via an oil film, and includes an oil chamber 10 of a hydraulic cylinder 10.
Braking is achieved by applying pressure oil to the a side to push the piston 100 closer to these plates, and the oil chamber 1
The brake is released by applying pressure oil to the 0b side and moving the piston 100 away from the plate.

Additionally, springs 103 are provided between each brake plate at four locations in the circumferential direction for each brake plate in order to speed up separation from the rotary plate. The hydraulic cylinder 10 has a stepped annular piston 100 that corresponds to a stepped annular hole (large diameter on the brake 2 side and small diameter on the far side (right side)) provided around the right side of the plate storage part of the brake 2. The oil chamber 10a that is fitted and formed on the right side of the large diameter part of the stepped ring hole is connected to the pressure oil discharge port on the servo valve 60 side via the oil passage 93a in the swing shaft 91, and is connected to the pressure oil discharge port on the side of the servo valve 60. The oil chamber 10b formed on the left side is also connected to a pressure oil discharge port on the servo valve 60 side via an oil passage 93b.

Note that on the side of the servo valve 60, a tank return side port is connected to the oil chamber 10b side, and on the side, a tank return side port is connected to the oil chamber 10a side.

Note that the stepped ring hole that constitutes the hydraulic cylinder 10 is formed by fitting a ring 95 on the base end side of the small diameter portion of the tip that should penetrate the bearing 27C of the swing shaft 91 and fixing it with a bolt 96 to increase its large diameter. A small gap is provided between the ring 95 and the shaft end of the rotating shaft 1.

An oil passage 94 penetrating through the center of the swing shaft 91 is connected to the oil passage of the rotary joint 92 on the right side, and to the oil passage 1a formed at the friction plate laminated portion and the center of the rotating shaft 1 on the left side. is bearing 27A,
It is connected to the installation position of 27B. This allows the bearings 27A, 27B to be removed from the oil passage of the rotary joint 92.
It becomes possible to supply lubricating oil to

In the device of the present invention as described above, a required torque is set in a torque setting device (not shown), and this is applied to the servo amplifier 80 (see FIG. 4) to output a corresponding signal, which is then applied to the servo valve 60. . Then, the corresponding pressure oil is supplied to the oil chamber 10a, and the piston 100 of the hydraulic cylinder 10 advances toward the brake 2 side to operate the brake 2. As a result, when the brake 2 is applied, the housing 3 of the brake 2 tends to rotate in the rotational direction. This braking torque equivalent force is detected by a load cell 18 provided between the arm 4 and an immovable part such as a base.

On the other hand, if you change the torque setting value using the torque setting device, the corresponding excitation current will change to the solenoid 60.
1 or 602, and as a result, an oil flow corresponding to the excitation current flows from the servo valve 60 to the oil chamber 1 of the cylinder 10.
0a or 10b, the braking force of the brake 2 is changed, and the amount of braking torque changes accordingly.

FIG. 4 is a block diagram of the control system of the device of the present invention, which includes all of the electrical system, hydraulic system, and mechanical system.

The rotational torque equivalent voltage e _s set by a torque setting device (not shown) is input to the servo amplifier 80 , and is subtracted by the feedback signal e ₂ from the load cell 18 in the adder 81 , and then the phase compensation circuit 82
The multiplier 84 multiplies the signal by PID, the multiplier 84 multiplies it by K ₁ , and the power amplifier 85 outputs it as K ₂ times.

Servo amplifier 80 outputs, that is, power amplifier 8
5 output is given to solenoids 601 and 602 as a solenoid excitation current of servo valve 60. This provides a flow rate, and this flow rate and the piston working pressure P _n have a pressure gradient constant K _p of 803. The difference between the pressure P _r corresponding to the spring force of the return springs 102 and 103 of the piston 100 and the piston working pressure P _n (P _n −P _r ) becomes the piston effective working pressure, which is the brake torque multiplied by the brake constant K _c of 804. _Tb
is obtained. Note that the load value obtained by dividing this by the length l of the arm 4 is detected by the load cell 18. The output of the load cell 18 is amplified by the feedback amplifier 18a, and its output _e1 is inputted to the absolute value circuit 86 of the servo amplifier 80 as a feedback signal. This e ₁ corresponds to its absolute value
Output e ₂ . On the other hand, Figure 5 shows the conversion characteristics.
Outputs _e2 which changes from 0 _to 10V in response to a change of e1 from 0 to ±5V. Conventionally, torque setting device output and load cell output use positive and negative voltages of 0 to ±5V.
In this embodiment, 0 to 10V is used as e _s , and by using the absolute value circuit 86, e ₂ is 0 to 10V.
can be used. This simplifies the calculation voltage circuit and facilitates signal processing.

[Effect of idea]

According to the device of the present invention as described above, since a flow rate control type servo valve is used, it can be put to practical use even with a large capacity braking torque of 2 tons-m or more without any problem in terms of capacity. Since the functions of the control type pressure control valve PV (see Fig. 6), the hydraulic cylinder, and the electromagnetic switching valve can be performed by one flow rate control type servo valve, the hydraulic system can be made inexpensive and compact. A double-acting cylinder is used as the hydraulic cylinder to control the hydraulic pressure of the brake, and flow control servo valves are used for the two oil chambers.
Even when changing the set braking torque, the corresponding oil flow is supplied to each oil chamber, so compared to the conventional single-acting hydraulic cylinder (see Fig. 6), it is possible to use a double-acting hydraulic cylinder and brake. works quickly,
Highly accurate transient characteristics can be achieved.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram showing the hydraulic system of the proposed device, Figure 2
Figure 3 is a cross-sectional view of the brake, Figure 3 is an enlarged view of the main parts of Figure 2, Figure 4 is a block diagram of the control system, Figure 5 is a graph showing the relationship between input and output of the absolute value circuit, and Figure 6 is FIG. 1 is a schematic configuration diagram of a conventional device. 1... Rotating shaft, 2... Brake, 3... Housing, 60... Flow rate control type servo valve, 100...
piston.

Claims (1)

[Scope of utility model registration request] A braking torque generating device for a load test, comprising a hydraulically actuated brake that is interlocked with the rotating shaft of a rotating machine to be tested and whose housing is swingable, and a hydraulic cylinder that controls the hydraulic pressure for the brake. and a flow rate control type servo valve that selectively supplies pressure oil to two oil chambers of the double-acting hydraulic cylinder. Braking torque generator for load testing featuring features.