JPH04258737A - Low-friction road running simulated tester - Google Patents

Abstract

PURPOSE:To fit a tester to a vehicle to be tested without requiring a special skill for a worker and prevent the disturbance caused by the fitting error when it is fitted. CONSTITUTION:A low-friction road running simulated tester is constituted of a control section comparing the preset friction coefficient and the friction coefficient calculated from the measured value for feedback control, a compressed air device section feeding the compressed air with the pressure controlled by the command signal sent from the control section to air springs 13, and an actuator section lifting a vehicle with a pressurized beam 12 supported by the air springs 13.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a simulation test device for evaluating the running of a vehicle on a low-friction road.

0002

2. Description of the Related Art Generally, there are two methods for carrying out a simulation test for driving a vehicle on a low-friction road. Firstly,
There is a method of laying a low-friction material such as Teflon on the outer peripheral surface of a roller of a chassis dynamometer on which vehicle tires are mounted. Second, there is a means for controlling the friction force acting between the rollers of the chassis dynamometer and the tires rolling thereon by adjusting the ground contact force between them.

[0003] Conventionally, as an example of implementing the above-mentioned second means, there is a method disclosed in Japanese Patent Application No. 1-59100 (Japanese Patent Application Laid-Open No.
-238341) has been proposed. In the example shown in FIG. 3, a connecting jig 5 provided at the free end of an arm 4 of a hub nut fixing device 3 is attached to a tire mounting bolt of a tire 2 of a vehicle 9 placed on a roller 1 of a chassis dynamometer. to pay. This connection jig 5 is equipped with a ball bearing, and the tire 2
It supports the body freely in rotation. The arm 4 is constructed by attaching the free end of a piston 8 of a hydraulic cylinder 7 provided on a support 6.

When simulating running on a low-friction road with a device configured as described above, the hydraulic pressure supplied to the hydraulic cylinder 7 is controlled in accordance with commands from the ground load controller, and the piston is operated to move the arm 4 up and down. This is done by applying a required upward force to the tire 2, lowering the ground contact load with the roller 1, and lowering the apparent frictional force.

[0005]

According to the first conventional means, if a low friction material such as Teflon or nylon is provided on the outer peripheral surface of the roller, the value of friction cannot be arbitrarily controlled. Furthermore, this configuration has a problem in that durability is low and the low-friction material is easily worn out, making maintenance work to repair it complicated.

Furthermore, according to the second conventional means, there is a problem in that it is difficult to attach the hub nut fixing device 3 to the tire 2. In other words, it is necessary to perform a set operation that involves the inside of the device, such as removing the hub nut fixing the tire 2, attaching an attachment to this part, and inserting and attaching the attachment to the bearing of the connection jig 5. Therefore, highly skilled workers are required. moreover,
Since the attachment is attached with a hub bolt, it is necessary to prepare an attachment that corresponds one-to-one with the hub for each vehicle model. Next, the connection jig 5 is attached to the tire 2.
When attaching the attachment, since the bolt is fitted into the mounting bolt hole and fastened, the eccentricity of the fastening portion will be about 1 mm. By the way, in the low friction road driving simulation test condition, the static wheel weight is 1/8 to 1/10
Since it is necessary to make precise adjustments so that

[0007] In view of the above-mentioned points, the present invention facilitates the work of installing a test device on a vehicle without requiring any skill, and
The object of the present invention is to provide a new low-friction road running simulation test device that eliminates disturbances caused by installation errors.

[0008]

[Means for Solving the Problems] The low-friction road running simulation test device of the present invention uses a friction coefficient between a tire and a roller specified in advance and a friction calculated from information from a detector actually installed in the test device. A control section that performs feedback control by comparing coefficients, a compressed air device section that sends compressed air at a predetermined pressure to an air spring based on a command signal sent from this control section, and a pressurized beam supported by the air spring. It is characterized by comprising an actuator part that is applied to the wheel support part of the vehicle under test and supported at a required height position.

[0009]

[Operation] With the above-mentioned configuration, under the control of the control unit, compressed air at a controlled pneumatic pressure is supplied from the compressed air device unit to the air spring, lifting the vehicle via the pressurizing beam and adjusting the height position. This has the effect of lowering the ground contact load between the tire and roller, and performing follow-up control to automatically set the apparent coefficient of friction to a predetermined value.

0010

[Embodiment] An embodiment of the low-friction road running simulation test device of the present invention will be described below with reference to FIGS. 1 and 2. In FIGS. 1 and 2, parts corresponding to the conventional example shown in FIG. 3 described above are given the same reference numerals, and detailed explanation thereof will be omitted. The basic idea of this example device is to simulate running on a low-friction road by controlling and adjusting the ground contact force between the tires of the test vehicle and the rollers of the chassis dynamometer. Further, the device of this example mainly includes an actuator section illustrated in FIG. 1, and a compressed air control device section and a control section illustrated in FIG. 2.

FIG. 1 is a schematic configuration diagram illustrating an actuator section, in which 1 is a roller of a chassis dynamometer, 2 is a tire, 9 is a vehicle, and 10 is a pit cover. pit cover 10
An actuator section is installed between the wheel support section 11 (vehicle's unsprung suspension, etc.) and a portion of the wheel support section 11 (such as a vehicle's unsprung suspension) that corresponds to the back side of the tire 2 of the vehicle 9. The actuator section consists of a pressure beam 12 and rubber bellow air springs 13 arranged at both ends of the pressure beam. The pressurizing beam 12 has an edge-shaped central portion, and this edge fulcrum portion 12a hits and supports a position as close as possible to the tire 2 in the wheel support portion 11. Further, both ends of the pressure beam 12 are bent in the direction of the tire 2 so as to largely sandwich the tire 2, and the center of the air spring 13 installed at each end of the pressure beam 12 is aligned with the edge fulcrum part 12a. The structure should be stable so that the Each air spring 13
The height position of the pressurizing beam 12 can be adjusted by injecting and adjusting compressed air from a compressed air device into the inside thereof.

The control section and the compressed air device section are shown in FIG.
The configuration is as shown in the example below. That is, the control section independently sets friction coefficients for the four wheels and performs follow-up control using feedback control. For this purpose, a four-wheel friction coefficient schedule reader 14 reads friction coefficient data corresponding to a predetermined test, and sends this data information to a four-wheel friction coefficient schedule command unit 15. The schedule command unit 15 sends a command signal for the friction coefficient value to be set for each tire 2 at each point in the test schedule.
It is sent to the friction coefficient comparator 16.

[0013] Also, wheel load detecting means 1 installed in the testing device
7 detects the wheel motion value and sends the output signal to the friction coefficient calculator 18. At the same time, the output signal detected by the brake force or driving force detection means 19 is transmitted to the friction coefficient calculator 18.
send to The friction coefficient calculator 18 processes each output signal to calculate a measured value of the friction coefficient, and sends a signal of the measured value to the friction coefficient comparator 16. The friction coefficient comparator 16 compares and corrects the command value of the friction coefficient with the actual measured value, generates a required control signal, and sends this control signal to the compressed air control command unit 20. At the same time, by sending the output signal of the friction coefficient comparator 16 to the four-wheel friction coefficient schedule command unit 15, follow-up control is performed by feedback control.

The compressed air control command unit 20 generates a command signal based on the control signal received here, and sends it to the compressed air device 21. The compressed air device 21 opens and closes an internal electromagnetic valve in response to a command signal, thereby supplying compressed air at a pressure corresponding to the command to the air springs 13, respectively.

The air spring 13 supplied with compressed air expands or contracts in response to the pressure, lifts the vehicle 9 with a required force via the pressurizing beam 12, and adjusts the height position. This lowers the ground contact load of the tire 2 with the roller 1, automatically sets the apparent friction coefficient to a predetermined value, and performs a running simulation test.

Furthermore, in this example device, during actual driving, the braking force or the driving force acts on the center of gravity of the vehicle as an inertial force,
It is also possible to simulate a situation where the front and rear wheel loads change due to the occurrence of an overturning moment. In this case, in the simulated driving test of the device of this example, the vehicle is not driven in the longitudinal direction, so no inertia force is generated during actual driving. However, as an alternative overturning force, a moment is generated due to the product of the height at which the vehicle is fixed and the fixing force (braking force or driving force). The wheel movement change caused by this moment can be generated naturally by bringing the spring constant of the air spring close to zero without active control, and the test can be carried out under conditions where no control delay occurs. Make it executable.

It should be noted that the present invention is not limited to the above-described embodiments, and it goes without saying that various other configurations may be adopted without departing from the gist of the present invention.

[0018]

Effects of the Invention As detailed above, according to the low-friction road running simulation test device of the present invention, information on the friction coefficient between the tire and roller specified in advance and the detector actually installed in the test device can be obtained. a control unit that performs feedback control by comparing the friction coefficient calculated from It consists of an actuator section that applies a pressurizing beam to the wheel support section of the vehicle under test and supports it at a required height. It feeds the spring, lifts the vehicle via the pressure beam, adjusts the height position, lowers the ground load between the tires and rollers, and automatically follows the apparent friction coefficient to set it to a predetermined value. This has the effect of making it possible to control and perform a good driving simulation test.

Further, when installing the device of the present invention on a vehicle under test, there is an advantage that the operator does not require special skill and can easily install the device. Furthermore, it is possible to eliminate disturbances caused by installation errors when the device of the present invention is installed in a vehicle.

[Brief explanation of the drawing]

FIG. 1 is a schematic configuration diagram of an actuator section showing an embodiment of a low-friction road driving simulation test device of the present invention.

FIG. 2 is a block diagram of a control section and a compressed air device section of the above embodiment.

FIG. 3 is a schematic perspective view illustrating a conventional device.

[Explanation of symbols]

1...roller 2...Tires 9...Vehicle 11...Wheel support part 12...Pressure beam 13...Air spring 14...Schedule reader 15...Schedule commander 16...Friction coefficient comparator 17...Wheel load detection means 18...Friction coefficient calculator 19...Driving force detection means 20...Compressed air control command unit 21...Compressed air device

Claims (1)

[Claims] [Claim 1] A control section that performs feedback control by comparing the friction coefficient between the tire and the roller specified in accordance with the test schedule with the friction coefficient actually measured and calculated from the tester; and a control section that performs feedback control; Based on the command signal, a compressed air device unit supplies compressed air at a controlled pressure to the air spring, and a pressurizing beam supported by the air spring lifts the wheel support part of the test vehicle and adjusts the height position. A low-friction road simulating test device comprising an actuator section configured to