JPH0457210B2 - - Google Patents

Description

[Detailed Description of the Invention] A. Purpose of the Invention (Field of Industrial Application) The present invention quickly evaluates the yudder (described later) of vehicle brakes using a stationary test instead of using an actual vehicle, and takes countermeasures against yudder. It can be used as a device that can be used effectively.

(Prior Art) When an automobile is braked, particularly at low speeds, vibrations and noise in the rotational direction of the wheels, such as rattling, may be generated in the brake section. This phenomenon is called jadar (or chatter).

Conventionally, in order to investigate this yudder, it has been necessary to use an actual vehicle to measure the vibration conditions when yudder occurs, measure the resonance point of the axle, and examine changes in the yudder occurrence situation due to changes in the brake structure. was.

The use of dynamometers for brake testing has been done in the past, but these were built with a rigid body design with the main purpose of firmly mounting the brakes in order to examine brake performance. No consideration has been given to examining the yander in relation to torsional elasticity, and therefore it has not been possible to perform simulation tests on the yardder using a dynamometer.

As a result of investigating the yander phenomenon through actual vehicle tests, the present inventors have learned the following.

(1) In drum brakes, vibration in the circumferential direction is the largest, and the phase of vibration is the same everywhere on the brake.

(2) As shown in Figure 4, the magnitude of vibration in the circumferential direction increases as the outer circumference of the brake increases, and its magnitude is proportional to the distance from the center of the axle.

(3) The torsional resonant frequency of the axle is equal to the yada frequency.

From this result, it was found that the jadder was caused by torsional resonance of the axle.

(Problem to be solved by the invention) However, in the test of a brake shoe, conventionally it was necessary to use an actual vehicle to measure the direction, magnitude, frequency, etc. of vibration. It takes a lot of man-hours and time for preparatory work such as replacing the wheels and drums, and since measurements are taken while the machine is running, it is difficult to move around and it is not possible to get close to the area where the jitter occurs.

B. Structure of the Invention (Means for Solving Problems) In order to eliminate the inconvenience of a wheeler test using an actual vehicle, the present invention provides a wheeler testing device using a dynamometer that can test and evaluate wheeler in the same way as an actual vehicle test. A vibration system (referred to as a brake flange in this specification) that has torsional vibration characteristics equivalent to those of an actual vehicle is incorporated into a part of the dynamometer, and the brake is connected to the dynamometer through this brake flange. It was designed to be installed on a vehicle to perform a jadder test.

The structure of wheels and axles in an actual vehicle is roughly as shown in FIG. 1A. 1 is the wheel, 2 is the tire,
3 is the brake drum, 4 is the bucking plate,
5 is a brake shoe held by the bucking plate 4, 6 is a knuckle, and 7 is an axle.

If this wheel portion is replaced with an equivalent vibration model, the result will be as shown in FIG. 1B. I is the moment of inertia of the bucking plate 4, brake shoe 5, knuckle 6, etc., kx is the torsional spring force of the axle 7,
k is the torsion spring constant and x is the torsion angle.
μw is the vibration suppressing force based on the friction between the brake shoe and the brake drum.

Therefore, as a flange to be incorporated into a dynamometer, we use a brake whose torsion spring constant k is equal to the torsional spring constant of the axle of the actual vehicle, and whose moment of inertia I, including the additional weight of the brake shoe and knuckle, is equal to the moment of inertia of the wheel of the actual vehicle. By making a flange, attaching it to the dynamometer, assembling the brake, rotating the brake drum with the motor, and pressing the brake shoe against the drum, it can be operated in the same way as the brake system on an actual vehicle. This is the translation.

The present invention provides a test device capable of conducting a yawder test by incorporating the brake flange manufactured as described above into a dynamometer.

(Function) Since the brake flange has torsional vibration characteristics equivalent to those of the axle, the occurrence of jitter is similar to that of an actual vehicle, and tests and measurements can be performed in a fixed position, and brake replacement can be performed quickly. Therefore, by using this testing device, it is possible to test the state of occurrence of jitter and to efficiently take measures to prevent jitter.

(Example) FIG. 2 is a partially cutaway side view showing a brake judder testing device according to the present invention.

8 is a motor that drives a rotating shaft 11 supported by bearings 9 and 10. A rotating body 12 having a moment of inertia equivalent to that of an automobile is attached to the rotating shaft 11. A brake drum 14 is fixed to the end of the rotating shaft 11 via a drum flange 13.
Reference numeral 15 denotes a measuring shaft rotatably supported by a bearing 16, and a torque arm 17 is fixed to the end of the measuring shaft.
By rotating, the lower end pushes the load cell 18. A brake flange 19 having a torsion spring constant k and a moment of inertia I determined according to the present invention is attached to the end of the measuring shaft 15 on the rotating shaft 11 side, and a brake shoe and a wheel cylinder are attached to this in the same way as a normal brake. Attach the backing plate 20. The brake shoe is opposed to the inner circumferential surface of a brake drum 14 attached to a drum flange 13 in the same state as a normal brake. 2
1 is an additional weight that can be attached to and removed from the brake flange 19 in order to change the moment of inertia of the brake flange 19 or to make it easier to cause torsional vibration.

The brake flange 19 is constructed as shown in FIG. That is, a coupling flange 22 for flange coupling to the measuring shaft 15, and a bucking plate 20.
The mounting flange 23 for attaching the shaft part 2
The four additional weights 21 are attached to the inner side of the mounting flange 23 with bolts 25, and the mounting flange 23 is equipped with a brake shoe 5 and a wheel cylinder (not shown). Installed and connected with oil pipe 26. 27 is a vibration acceleration pickup attached to the mounting flange 23.

The diameter of the shaft portion 24 of the brake flange 19 is determined so that the shear stress due to the maximum brake torque during the test does not exceed an allowable value.

In addition, the moment of inertia I of the brake flange 19
can be determined as follows.

f: Torsional resonance frequency k: Torsional spring constant G: Transverse elastic modulus J: Torsional coefficient L: Length of the shaft portion 24 D: Diameter of the shaft portion 24, k=GJ/L (2) J=πD ⁴ /32 (3) Substituting equation (2)(3) into equation (1), I=GD ⁴ /128πf ²・L (4) According to equation (4), It is possible to determine the moment of inertia of the brake flange that acts in the same way as on an actual vehicle.

The brake flange 19 made in this way is attached to the dynamometer shown in FIG. 8 and sends pressure oil from the oil pipe 26 to the foil cylinder.
When the brake drum 14, which rotates together with the drum flange 13, is braked, if the brake is in a state where it causes yudder on an actual vehicle, it will cause yudder, and the vibration at that time will be collected as a vibration acceleration pickup 2.
Measure with 7 mag. Further, torque fluctuations, rotational speed, etc. can also be measured using the load cell 18 or other measuring instruments.

As a result of testing using the test device configured as described above, the following was found.

(1) Although the situation in which yadding occurs varies depending on the nature of the lining, the ranking of linings that are more likely to cause yadding in actual vehicles was the same in dynamometer tests.

(2) As mentioned above, sagging is caused by torsional vibration of the axle, but the same result was obtained in a test using a dynamometer. Just as the frequency of the yudder in the actual vehicle was the same as the resonant frequency of the axle, the frequency of the yudder that occurred was the same as the resonant frequency of the brake flange.

(3) In actual vehicle tests, when sagging occurred, torque build-up was always accompanied, and the same was true in dynamometer tests.

(4) Yadder occurs when the vehicle is about to stop, both in the case of an actual vehicle and in the case of a dynamometer.

C. Effects of the Invention (1) Since the shaft portion 24 of the brake flange 19 has torsional elasticity equivalent to that of the axle of an actual vehicle, by incorporating this into a dynamometer, a simulation test using the dynamometer can be conducted.

(2) Testing work is extremely easy because it is possible to perform a stationary test using a dynamometer without using an actual vehicle.

(3) For example, various types of brakes (brake drums,
In the case of an actual vehicle, it took a lot of time to replace and test the brake shoe (brake shoe), and it was extremely inefficient as it took a week to prepare and test, but the preparation work was significantly reduced. It can be done efficiently in a short time.

(4) By changing the additional weight 21, it is possible to obtain data on the limits and preventive measures for the occurrence of judder, and it is also possible to test brakes of different sizes.

[Brief explanation of the drawing]

FIG. 1A is a longitudinal sectional view showing the wheel portion of an automobile;
Fig. 1B is a diagram showing an equivalent vibration model of this, Fig. 2 is a side view with a part cut away of the brake judder test device according to the present invention, Fig. 3 is a perspective view of the brake flange, and Fig. 4 is a diagram showing an equivalent vibration model. FIG. 2 is a schematic perspective view showing a vibration state of a brake drum when a yander occurs. 1: Wheels, 2: Tires, 3: Brake drums,
4: Bucking plate, 5: Brake shoe,
6: Nutacle, 7: Axle, 8: Motor, 9,1
0: Bearing, 11: Rotating shaft, 12: Rotating body, 13:
Drum flange, 14: Brake drum, 15:
Measuring axis, 16: Bearing, 17: Torque arm, 1
8: Load cell, 19: Brake flange, 2
0: Bucking plate, 21: Additional weight, 2
2: Connection flange, 23: Mounting flange, 2
4: Shaft, 25: Bolt, 26: Oil pipe, 27:
Vibration acceleration pick up.

Claims (1)

[Claims] 1. A rotating body 12 having a moment of inertia equivalent to that of a vehicle is attached to a rotating shaft 11 supported by bearings 9 and 10 and driven by a motor 8, and a brake drum 14 can be freely attached to the end of the rotating shaft 11. 1
6, and a torque arm 1 at one end.
7 is attached to the other end of the measuring shaft 15 facing the load cell 18, in which a bucking plate 20 with a brake shoe and its driving part attached thereto can be freely attached. A brake judder testing device characterized in that a bucking plate 20 is attached to a measuring shaft 15 via a brake flange 19 that has a coupling flange 22 and a mounting flange 23 at both ends of a shaft portion 24 having torsional elasticity. .