JPH0599797A - Chassis dynamometer and its testing method - Google Patents

Abstract

PURPOSE:To enable a test which simulates a low or high friction road state to be executed with a small error and obtain a chassis dynamometer which is simple in structure and inexpensive and its testing method. CONSTITUTION:A chassis dynamometer is constituted so that a pad base 7 of a road roller 2 is installed through a road cell 19, at the same time a pad base 8 of a free roller 3 is installed side by side, and a wheel 6 is rolled above an area between the road roller 2 and the free roller 3 for testing. The movable frame 17 is moved and adjusted while reading the value of the road cell 19 and an apparent friction force for a wheel is adjusted for testing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved configuration of a chassis dynamometer for performing a low friction road traveling simulation and a test method thereof.

[0002]

2. Description of the Related Art Generally, a chassis dynamometer is used as a device for conducting a test in a running state of a vehicle. In this, various running states such as high speed and low speed, and various states such as climbing and descending plate running can be simulated on the roller to perform a test. In recent years, chassis dynamometers have been used to test low friction road surface conditions on ice and snow, as well as vehicles equipped with ABS (anti-lock brake system) and vehicles equipped with trunk control. Has been requested.
Therefore, conventionally, instead of changing the friction coefficient between the tire of the vehicle under test and the roller of the chassis dynamometer, by adjusting the wheel load applied to the roller, it is possible to simulate a road surface with an arbitrary friction coefficient. 5 to FIG.
A chassis dynamometer such as that shown in FIG. As shown in FIG. 5, the front and rear wheels of the automobile 1 are placed on two rollers 2 and 3, respectively, and the flywheel 4 and the dynamometer 5 are connected to the rollers 2 so that the characteristics of the automobile 1 can be maintained on the chassis. It is configured to measure.
Further, the rollers 2 and 3 supporting the tire 6 of the automobile 1 are configured as shown in FIG. 6, and the front roller 2 is rotatable on the pedestal 7 and the rear roller 3 is rotatable on the pedestal 8. Is supported by. The front pedestal 7 is fixedly supported by a fixed base 9. The pedestal 8 at the rear is installed on the vertical moving table 10. The vertical moving table 10 can be moved and adjusted in the vertical direction along the guide 12 by the screw feeding mechanism 11 arranged on the horizontal moving table 13. The horizontal moving base 13 is configured to be movable and adjustable in the horizontal direction along the guide 15 by the screw feeding mechanism 14 arranged on the fixed base 9.

Next, the principle when the apparent friction coefficient between the tire 6 and the roller 2 is changed by the conventional chassis dynamometer configured as described above to cause slippage is shown in FIG. Explained by. First, if the force applied by the tire 6 part to the rollers 2 and 3 is θ ₂ > θ ₃ , F
The ₂ <F _3. Here, when θ ₃ is brought close to 0, F ₂ becomes 0
Approach. When the vehicle 1 is braked after steady operation, the tire 6 portion tries to reduce the rotational speed, but the roller 2 tries to continue to rotate due to the rotational inertia of the flywheel and the dynamometer. Therefore, if F ₂ is large, no slippage occurs between the tire 6 and the roller 2, but if F ₂ is small, the frictional force between the tire 6 and the roller 2 becomes small, and slippage occurs between them.

By adjusting the relative distances and height positions of the rollers 2 and 3 as described above, even a tire 6 having an arbitrary diameter causes a slip between the roller 6 and the roller 2 and a low friction road surface condition is obtained. It enables testing of anti-lock brake systems and the like.

[0005]

The conventional chassis dynamometer rollers 2 and 3 and the tire 6 configured as described above.
The relational principle of the statically determinate model with is sufficiently satisfied when the tire 6 is a single body. However, in an actual vehicle, there are front wheels, rear wheels, and a vehicle body, which interfere with each other and have a statically indeterminate structure in which the force cannot be obtained only by a force balance condition. In such a statically indeterminate structure, the force acting on each part of the structure cannot be simply calculated, but according to the result calculated by the computer, even if the angle of the contact point between the tire 6 and the rollers 2, 3 is changed, the roller 2 The contact force of 1 does not change so much, and the frictional force between the tire 6 and the roller 2 may not be sufficiently adjusted.

Further, in the prior art, in order to simulate a low friction road, the angle θ ₂ formed between the point at which the roller 2 and the tire 6 contact and the vertical line is increased, and the contact point between the roller 3 and the tire 6 is increased. The angle θ ₃ formed by the vertical line and the vertical line is set to be small, and even if the tire 6 slightly moves horizontally, the contact force between the roller 2 and the tire 6 fluctuates significantly, and the apparent friction force is changed. Will change greatly. Therefore, when the antilock brake system is tested by the conventional device, the braking of the brake is generated in pulses, so that the tire 6 vibrates in the front-rear direction. This tire 6
The contact force between the roller 2 and the tire 6 changes greatly in accordance with the movement in the front-back direction, and the frictional force between these changes greatly, resulting in a large error in the test results. There was a problem.

Further, in the conventional device, the device for moving the roller 3 in the vertical or horizontal direction is complicated and expensive. Further, in the case where not only the roller 3 but also the roller 2 is moved, the roller 2
Dynamometer 5 and flywheel 4 connected to
However, there is a problem that the entire device becomes very expensive.

In view of the above points, the present invention newly provides a chassis dynamometer which is capable of stably adjusting and setting the frictional force, performing a test simulating a low friction road with a small error, and having a simple structure and low cost. The purpose is to

[0009]

A chassis dynamometer according to the present invention comprises a pedestal for rotatably supporting a load roller and a load cell mounted on a movable frame whose position can be adjusted in the front-back direction of a vehicle under test. And a pedestal that supports the free roller to rotate freely on the movable frame in parallel with it, and rolls the drive wheel of the vehicle under test on the upper part between the load roller and the free roller. Set the vehicle to
It is characterized in that the test is performed using a dynamometer or the like connected to the load roller.

Further, in the test method of the present invention, the movable frame of the chassis dynamometer described above is moved and adjusted, and the contact force between the load roller and the wheel of the vehicle under test is changed and adjusted while measuring the load cell. It is characterized by adjusting the frictional force of the vehicle to a required value and setting various road conditions from the normal friction coefficient road condition to the low friction road condition or the high friction road condition. ..

[0011]

According to the present invention as described above, one chassis dynamometer can continuously perform tests corresponding to friction coefficients of various roads.

[0012]

Embodiments of the chassis dynamometer and the test method therefor according to the present invention will be described below with reference to FIGS.
1 to 4, parts corresponding to those of the conventional example shown in FIGS. 5 to 7 are designated by the same reference numerals, and detailed description thereof will be omitted.

FIG. 1 is a schematic explanatory diagram showing a state in which a vehicle is being tested with a chassis dynamometer. In the figure, 1 is an automobile, 2 is a road roller, 3 is a free roller, 6 is a tire, and 7 and 8. Is a cradle. The front and rear parts of the automobile 1 are fixed to predetermined positions on the chassis dynamometer by using chain blocks 16, respectively.

Each tire 6 of the automobile 1 is placed so as to straddle between the road roller 2 and the free roller 3. Each road roller 2 is connected to a flywheel and a dynamometer via a coupling (not shown).

Each load roller 2 is rotatably supported by a receiving table 7, and each free roller is rotatably supported by a receiving table 8.

Further, in the apparatus of this embodiment, a pair of the load roller 2 and the free roller 3 to be brought into rolling contact with the front wheels of the automobile 1 is installed on the movable frame 17, and the load roller 2 to be brought into rolling contact with the rear wheels is free. The pair with the roller 3 is installed on the fixed frame 18. At this time, each pedestal 7 of the load roller 2 is arranged on each movable frame 17 or fixed frame 18 via the load cell 19. This load cell 19 is for measuring a vertical load applied to the load roller 2, and it is desirable that a plurality of load cells 19 are arranged immediately below the axis of each of the pedestals 7 and 8 and at a target position based on this. Further, each cradle 8 of the free roller 3 is directly installed on the movable frame 17 or the fixed frame 18, respectively. When a plurality of load cells 19 are arranged as described above, each load cell 19
The horizontal component force and the vertical component force acting on the pedestal 7 can be easily calculated from the relationship between the distance between them and the vertical distance from the position where the load cell is installed to the center of the bearing.

The movable frame 17 provided with the rollers 2 and 3 as described above is a moving device for adjusting the difference in the wheel base length of the vehicle under test 1. Attach so that it can be moved and adjusted. In this example,
A pair of clamp rail portions (not shown) are laid on the floor 21, and the rail portions are reciprocally mounted by rolling with wheels (not shown) installed on the movable frame 17.

Further, as a device for reciprocating the movable frame 17, a pair of driving members 20 are laid in parallel between the pair of rail portions. The driving member 20 is formed by laying a chain via a bracket on the upper long groove portion of a fixed strip member, which is a long member with grooves, provided in parallel with the rail portion. Further, a sprocket (not shown) which is rotated by a drive motor is mounted on the movable frame 17 side. The sprocket is meshed with the chain of the driving member 20 described above, and the drive motor is normally or reversely rotated, so that the movable frame 17 can be moved to a desired position. In this example, the movable frame 17 is moved by using the chain, but not limited to this, the movable frame 17 may be moved by using other means such as a feed screw mechanism.

The fixed frame 18 is fixedly installed on the floor 21 using foundation bolts.

Next, the test method by the chassis dynamometer of the present embodiment configured as described above and its operation will be described. First, the vehicle 1 to be tested is installed on the chassis dynamometer as shown in FIG. At this time, in order to obtain a road surface condition having a predetermined friction coefficient for simulating running, the set position of the vehicle 1 is set to be a chain block so that the reading value of the load cell 19 at which the contact force between the road roller 2 and the tire 6 becomes a predetermined value. 1
Set with 6. Next, the movable frame 17 is slightly moved to
The load roller 2 and the tire 6 are adjusted to have a set friction value, as shown in, so that the reading value of the load cell 19 is obtained. Then, the test is usually performed in this state.

Next, in order to make the apparent friction coefficient variable by changing the contact force between the road roller 2 and the tire 6, the fact that the spring constant of the tire 6 is relatively small is used. This is done by changing and adjusting the relative position in the horizontal direction between the load roller 2 and the load roller 2. This will be described with reference to FIGS. 2 to 4 using the state on the movable frame 17 side as a model.

First, from the state of the normal friction path shown in FIG.
When shifting to the state of the low friction road shown in FIG. 3, the movable frame 17 is moved in the front direction of the vehicle 1 from the neutral position of FIG. 2 to obtain the state shown in FIG. This allows the tire 6
Moves horizontally from the central position between the load roller 2 and the free roller 3 toward the free roller 3 side. As a result, the tire 6 comes into contact with the road roller 2 with a relatively light contact force, the amount of deformation of the pressure contact portion becomes small, the apparent frictional force between them becomes small, and a low friction road state is realized. Further, when the load roller 2 is horizontally moved to the side opposite to the load roller 2, the load roller 2 and the tire 6 finally come into a non-contact state, and the apparent friction coefficient becomes zero.

Next, in order to bring the high friction road into a state, the movable frame 17 is moved from the position shown in FIG. 2 or 3 to the position shown in FIG. That is, the movable frame 17 is moved to the rear of the vehicle 1, and the tire 6 is relatively horizontally moved to the road roller 2 side. As a result, the tire 6 is pressed against the road roller 2 with a strong contact force and is largely deformed. As a result, the apparent friction coefficient is increased, and a high friction road state is realized.

As described above, in the chassis dynamometer of this embodiment, a wide range of test conditions from a normal friction road condition to an arbitrary low friction road condition or a high friction road condition can be continuously variably adjusted, and various running simulations can be performed. It makes the test feasible.

Further, in the device of this embodiment, the angle formed by the contact point between the road roller 2 and the tire 6 and the vertical line passing through the center position of the tire 6 can be set small, so that the load movement during the brake test can be prevented. It can be made relatively close to reality.

The present invention is not limited to the above-mentioned embodiments, and it goes without saying that various other configurations can be adopted without departing from the gist of the present invention.

[0027]

As described in detail above, according to the chassis dynamometer and the testing method thereof of the present invention, the load roller can be freely rotated on the movable frame whose position can be adjusted in the front-back direction of the vehicle under test. A pedestal that supports is installed via a load cell, and in parallel with this, a pedestal that supports the free roller to freely rotate is installed on a movable frame, and the pedestal is placed above the load roller and the free roller. The vehicle is set to roll the drive wheels of the test vehicle, and the test is performed using a dynamometer or the like connected to the load roller.The movable frame of the chassis dynamometer is moved and adjusted, The contact force between the load roller and the wheel of the vehicle under test is changed and adjusted while measuring the load cell, and the apparent friction force during that time is adjusted to the required value, and the normal friction coefficient road condition is changed. Low friction road conditions, or to a high friction road condition is intended to allow the testing by setting various road conditions. Therefore, there is an effect that it is possible to continuously execute tests corresponding to the friction coefficients of various roads with one chassis dynamometer.

Since the structure of the movable frame for changing the friction coefficient between the road roller and the wheels can be shared with the structure for adjusting the difference in the wheel base length of the vehicle under test, This has the effect of simplifying the configuration and providing an inexpensive product.

[Brief description of drawings]

FIG. 1 is a schematic configuration explanatory diagram showing an embodiment of a chassis dynamometer of the present invention.

FIG. 2 is a schematic explanatory diagram of main parts illustrating a test state of a normal friction coefficient road according to the above-described embodiment.

FIG. 3 is a schematic explanatory diagram of a main part illustrating a test state of a low friction road according to the above-described embodiment.

FIG. 4 is a schematic explanatory diagram of main parts illustrating a test state of a high friction road according to the above-described embodiment.

FIG. 5 is a schematic explanatory diagram showing a test state of a conventional chassis dynamometer.

FIG. 6 is a schematic configuration diagram of a tire and a roller portion of the conventional example.

FIG. 7 is an explanatory diagram illustrating a load relationship during rolling of the tire and roller of the conventional example.

[Explanation of symbols]

1 ... Car, 2 ... Roller, 3 ... Roller, 6 ... Tire, 7
... pedestal, 8 ... pedestal, 17 ... movable frame, 18 ... fixed frame, 19 ... load cell, 20 ... driving member.

Claims (2)

[Claims] 1. A chassis for performing a test by rolling a drive wheel of a vehicle under test on an upper portion between a load roller for connecting a dynamometer and the like and a free roller arranged side by side with the load roller. In the dynamometer, a movable frame that is movable in the front-rear direction of the vehicle under test is mounted, a cradle that supports the load roller is installed on the movable frame via a load cell, and the free roller is received. Chassis dynamometer characterized by having a stand installed. 2. When performing a test using the chassis dynamometer according to claim 1, the movable frame is horizontally moved and adjusted toward the front and rear of the vehicle under test while reading the value of the load cell, and the load roller and the vehicle under test are adjusted. The test method of the chassis dynamometer, characterized in that the contact force with the wheels of the vehicle is adjusted to adjust the frictional resistance between them.