JPH0452544A - Measuring apparatus of resistance in rotation of tyre - Google Patents

Abstract

PURPOSE:To highly accurately detect the traction due to the resistance when a tyre is rotated by pressing a load sensor by a swaying arm to which the traction is added, thereby to obtain a correct input to the load sensor with a small traction. CONSTITUTION:When the rotating resistance of a tyre 13 is to be measured, as a traction vehicle 30 runs in a manner to make constant the speed of a measuring cart 10, the traction load of the cart 10 is added to a ball joint 23. An arm 22 is ready to sway around a shaft 51 toward the rear side of the vehicle. At this time, a load corresponding to the traction of the cart 10 is added through a projecting part 26 colliding against the arm 22 to press a load sensor 24. Therefore, if the ratio between the swaying radius around the joint 23 coupling the arm 22 with the cart 10 and the swaying radius of the pressing point is suitably set, a desired level of the load which is changed corresponding to the traction can be obtained. Accordingly, the load, that is, rotating resistance of the tyre can be detected with high accuracy even with a small traction.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a tire rolling resistance measuring device, and more particularly to a tire rolling resistance measuring device that measures the rolling resistance of a tire by a traction method using a load sensor. .

(Prior art) Conventionally, when measuring the rolling resistance of a tire, for example, an indoor tire test@(drum type, flat belt type, etc.)
A method has been adopted in which the resistance component is measured by using the same as a measuring device. In addition, when measuring tire rolling resistance on an actual vehicle, the coasting method is used to measure μ, W (rolling resistance bone) 10 μ, ■! (air resistance bone) and rolling resistance coefficient μ
, or by attaching a road wheel type six-component force meter or road wheel torque meter to the axle to measure the driving resistance during constant wandering.

On the other hand, there is a method for measuring traction force using a load sensor, for example, as described in Japanese Patent Application Laid-Open No. 110576/1983, as shown in FIG. This device detects the load by directly deflecting the shaft when attaching the traction part of an agricultural tractor.When the shaft end 2 in the figure receives a load P in the direction perpendicular to the axis from the traction link 1, The shaft end portion 2 is deflected in the same direction as the load, and the shaft center portion 5 is deflected in the opposite direction to the load, and this deflection is used to detect the traction load. Furthermore, as shown in FIG. 7, Japanese Utility Model Application Publication No. 56-62009 discloses that the shaft 7 is deflected by the load from the traction link 6, and this deflection is detected by a switch 9 attached to the transmission case 8. What was done is listed. In any case, these are for measuring large traction forces.

(Problems to be Solved by the Invention) However, in the conventional tire rolling resistance measuring method described above, tire rolling resistance can only be measured indirectly, and therefore it is difficult to measure tire rolling resistance with high accuracy. It was difficult.

On the other hand, for example, it is possible to adopt a traction method and measure the tire rolling resistance from the measured value of the traction force, but in this case, the tire rolling resistance is very small (rolling resistance coefficient μr''# 0.015), it is not possible to directly apply the method of a device with a large measured load value, such as a conventional traction force measuring device.

That is, it is difficult to deflect the load sensing shaft with a very small traction force, and even if a shaft that can be easily deflected is used, highly accurate tire rolling resistance measurement cannot be expected.

The present invention was made in view of such conventional problems, and aims to improve measurement accuracy of tire rolling resistance by providing a mechanism that can accurately input small traction forces to a load sensor. shall be.

(Means for Solving the Problems) In order to achieve the above-mentioned object, the present invention provides a measuring trolley on which a tire to be measured whose rolling resistance is to be measured is mounted, and a measuring trolley provided at the front of the measuring trolley so as to be easily accessible from a towing vehicle. a traction member that transmits traction force to the measurement cart; a sensor housing fixed to the towing vehicle; an arm attached to the sensor housing so as to be swingable back and forth; and a swinging portion of the arm and the traction member that swing together. It is characterized by comprising a ball joint that can be freely connected, and a load sensor that is housed in a sensor housing and that inputs the load from the arm. Preferably, the arm directly connects the load sensor. or one that indirectly presses the load sensor through a link member provided between the arm and the load sensor, and furthermore, a buffer member is provided between the sensor housing and the arm. It may be something.

(Function) In the present invention, the arm attached to the sensor housing so as to be swingable back and forth presses the load sensor depending on the magnitude of the tractive force that pulls the measurement cart.

Therefore, it is possible to obtain a desired level of load that changes depending on the traction force by appropriately setting the ratio of the swing radius of the center point of the ball joint that connects the arm and the measuring cart to the swing radius of the load sensor press point. This enables highly accurate load detection, that is, tire rolling resistance measurement, even with a small traction force.

(Example) Hereinafter, the present invention will be explained based on the drawings.

FIG. 1.2 is a diagram showing a first embodiment of the present invention.

First, the configuration will be explained.

In FIG. 1.2, 10 is a measuring cart, 2o is a load detection unit that detects the traction force that pulls the measuring cart 10, and 30 is a towing vehicle.

The measurement trolley 10 includes a frame-shaped trolley body 11, a pair of left and right leaf springs 12 mounted below the trolley body 11, and tires to be measured 13 mounted on the left and right sides of the trolley body 11 whose rolling resistance is to be measured. , a beam axle (not shown) that is supported by a leaf spring 12 and pivotally supports the tire to be measured 13, front and rear weights 14 and 15 that are removably attached to the truck body 11 in order to change the wheel load, and the front end of the truck body 11. The vehicle is equipped with a traction member 16 that is attached to the tow vehicle 30 and transmits the traction force from the towing vehicle 30 to the main body of the truck.

The load detection unit 20 includes a sensor housing 21 fixed to the rear end of the towing vehicle 30, an arm 22 swingably attached to the sensor housing 21 so that a swinging portion 22a on the upper end side swings back and forth, and Arm 22
The arm 22 includes a ball joint 23 that swingably connects the upper end of the arm 22 to the traction member 16, and a load sensor 24 housed in the sensor housing 21 so as to abut against the middle part of the arm 22. The load sensor 24 has a sensor main body 25
The projection 26 is pressed by the arm 22 with a load corresponding to the traction force that pulls the measuring cart 10, and the strain gauge built-in absorbs the strain of the sensor main body 25 under this load. It is input by a strain gauge (not shown) in section 27. The ball joint 23 also has a pole stud portion 28 fastened to the arm 22.
and a socket portion 29 fixed to the traction member 16 and rotatably engaged with the stud portion 28, allowing relative movement between the measurement cart 10 and the traction vehicle 30. Further, the sensor housing 21 includes an arm 22.
A stopper bolt 31 and an elastic stopper 32 are attached to limit the back and forth swing stroke.

The stopper bolt 31 is threadedly connected to a bracket 33 formed on the sensor housing 21, and is connected to a nut 34.
Fixed by The elastic stopper 32 is made of rubber, for example, and absorbs the impact when the towing vehicle 30 is braked so that the measurement cart 10 is not subjected to an impact due to inertia.

In addition, in FIG. 1, 41 is the rear wheel of the towing vehicle 30;
42 is a rear end member of the towing vehicle 30 to which the sensor housing 21 is fixed; 43 is a shackle that movably connects the rear end of the truck main body 11 and the rear end of the leaf spring 12. Further, in FIG. 2, 51 is a shaft that swingably supports the arm 22, 52 is a nut that fixes the stud portion 28 to the arm 22, and 53 is a bolt 54.
The sensor body 25 is fixed to the sensor housing 21 with a bracket, and the sensor body 25 is attached with a bracket 53.
The bolt 56 is a stay that supports the elastic stopper 32, and X in the figure is a gap with a slight allowance added to the actual deflection of the sensor body 25 based on the measurement range of the traction load. .

Next, the effect will be explained.

First, in order to measure the rolling resistance of the tire to be measured 13,
When the towing vehicle 30 travels to keep the vehicle speed of the measuring truck 10 constant, the traction load of the measuring truck 10 is applied to the ball joint 23, and the arm 22 tends to swing toward the rear of the vehicle around the shaft 51.

At this time, the protrusion 2 that abuts the middle part of this arm 22
6, a load corresponding to the traction force of the measurement cart 10 is applied to the sensor main body 25. In that case, the sensor main body 2
The load applied to the shaft 51 acting on the arm 22
From the relationship of the balance of the surrounding moments, the radius from the swinging center of the arm 22 to the joint center of the ball joint 23, and the radius from the swinging center of the arm 22 to the abutting point of the arm 22 and the protrusion 26. It is detected as a value that amplifies the traction load by the amount of . Therefore, the measuring cart 10
Even if the traction force pulling the sensor is small, a desired detection load level can be set by appropriately setting the radius ratio, and highly accurate measurement can be performed.

On the other hand, if the measurement cart 10 becomes difficult to pull due to some abnormality and an excessive load outside the predetermined range is applied to the arm 22, the stopper bolt 31 prevents the arm 22 from bending abnormally. Therefore, an excessive load is not applied to the load sensor 24, and the reliability of the load sensor 24 is increased. In addition, when braking the towing vehicle 3 degrees, the measuring trolley 1
0 tries to collide with the towing vehicle 30 due to inertia, but the collision energy is absorbed by the elastic stopper 32.
Damage to the measuring cart 10 and the towing vehicle 30 is prevented.

As described above, in this embodiment, the ratio of the swing radius of the center point of the ball joint 23 connecting the arm 22 and the measuring cart 10 to the swing radius of the pressing point of the load sensor 24 (protrusion 26) is determined. By appropriately setting , it is possible to obtain a desired level of load that changes depending on the traction force. Therefore, even a small traction force due to tire rolling resistance can be detected with high precision, and tire rolling resistance can be measured with high precision.

FIG. 3 is a diagram showing a second embodiment of the present invention.

In the following embodiments, the same components as those in the other embodiments described above will be denoted by the same reference numerals, and the explanation thereof will be omitted.

As shown in the figure, in the second embodiment, the arm 22
A link member 61 and a bottle 6 interposed between the arm 22 and the sensor main body 25 transmit the load from the load sensor 24 to the load sensor 24.
2.63.

Even in this case, the same effects as in the first embodiment can be obtained. Further, in the first embodiment, a loss occurs due to the abutment between the arm 22 and the protrusion 26, whereas in the second embodiment, there is no such loss and the load can be efficiently transmitted. Therefore, measurement accuracy is further improved.

FIG. 4 is a diagram showing a third embodiment of the present invention.

As shown in the figure, in this embodiment, in addition to the device of the second embodiment, a damper 71 (buffer member) is swingably interposed between the sensor housing 21 and the arm 220 by means of bins 72 and 73. There is.

Even in this case, the same effect as in the 1.2 embodiment can be obtained, and furthermore, the movement of the arm 22 can be made smoother.

FIG. 5 is a diagram showing a fourth embodiment of the present invention.

As shown in the figure, in this embodiment, a load sensor 24 is attached to the sensor housing 21 in front of the arm 22, and a tensile load is applied to the link member 81 interposed between the load sensor 24 and the arm 22. I have to.

Even in this case, the same effects as in the first to third embodiments can be obtained.

(Effects) According to the present invention, the load sensor is pressed by the swinging arm that applies the traction force, and even a small traction force can be accurately input to the load sensor, so the traction force due to tire rolling resistance can be detected with high precision. It is possible to improve the measurement accuracy of tire rolling resistance.

[Brief explanation of drawings]

Fig. 1.2 is a diagram showing a first embodiment of the tire rolling resistance measuring device according to the present invention, Fig. 1 is an overall configuration diagram thereof, and Fig. 2 is a main part configuration diagram showing its load detection section. , FIG. 3 is a configuration diagram of main parts showing a second embodiment of the tire rolling resistance measuring device according to the present invention, and FIG. 4 is a diagram showing a third embodiment of the tire rolling resistance measuring device according to the present invention. Fig. 5 is a block diagram of main parts showing a fourth embodiment of the tire rolling resistance measuring device according to the present invention. FIG. 6.7 is a configuration diagram of a conventional traction load detection device for measuring the traction force of an agricultural tractor or the like. 10... Measuring trolley, 13... Tire to be measured, 16... Traction member, 21... Sensor housing, 22... Arm, 23...Ball joint, 24...Load sensor, 30...Tow vehicle, 32...Elastic stopper (buffer member), 71...
...damper member (buffer member), 61.81...
...Link components. Figure 2

Claims (1)

[Scope of Claims] A measuring trolley on which a tire to be measured whose rolling resistance is to be measured is mounted; a traction member provided on the measuring trolley and transmitting traction force from a towing vehicle to the measuring trolley; and a traction member fixed to the towing vehicle. an arm attached to the sensor housing so as to be swingable back and forth; a ball joint that swingably connects a swinging portion of the arm to a traction member; A tire rolling resistance measuring device comprising: a load sensor that inputs a load; and a tire rolling resistance measuring device.