JPS585374B2 - Tire Shikenkinioker Kajiyuufukasouchi - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an apparatus for applying a load to a tire in a tire testing machine such as a tire uniformity testing machine.

For example, a load applying device in a tire uniformity testing device must apply a load to a tire within a required accuracy for a certain set value.

Taking passenger car tires as an example, a drum applies a load of 200 to 1,000 kp to an inflated tire, but in this case, a high accuracy of about ±5 to ±20 kg is required.

Therefore, conventionally, the tire load is detected by a load detection load cell, and the drive source for the load is controlled based on this detection signal, thereby achieving the above-mentioned accuracy.

Specifically, the methods are roughly divided into the methods shown in FIG. 3A20.

In FIG. 3A, a threaded rod C is directly connected to a drum holder b that supports a drum a, and this threaded rod C is screwed into a nut d that rotates at a fixed position.

Connect this nut d to motor M1 chain e1 sprocket f
The threaded rod C is advanced by rotating through the drum A, and the drum a is pressed against the tire T.

This load is detected by a load cell (not shown) or the like, and the motor M is decelerated in proportion to the difference between the detected value and the set value, and when both become constant, the drive motor M is stopped.

In such a device, the control system, that is, the load cell, has a slow response speed from when it detects the load to when it decelerates the motor M. Therefore, if the pressing speed of the drum a is increased, it will cause disturbances and an excessive load will be applied to the drum. There is a risk of destroying the load cell.

Furthermore, in the above device, all of the drum's load is applied directly to the threaded part of the threaded rod C and the nut d, so the threads of both are subject to severe wear, resulting in poor accuracy, poor durability, and the need for a very large motor M. There was also the problem of requiring output.

The device shown in Figure 3 is disclosed in U.S. Pat. No. 3,534,598, and connects the piston rod h of cylinder g and drum holder b, and also allows cylinder g to be moved to guide rod i. A screw rod C is fixed to the rear of the cylinder g, and a nut d is attached to this screw rod C.
are screwed together, and this nut d is rotated via motor M1 chain e.

To press drum a against tire T, use piston rod h
The drum A is pushed against the tire T by protruding, and the load is detected by a load cell (not shown). If the detected load differs from the set value, the motor M is rotated and the threaded rod C is slightly moved to set the load. Match value.

This device can be faster than the device shown in Fig. 3A in that the initial load is applied by the cylinder g and the fine adjustment is made by the motor M, but the entire tire load is still applied to the threaded rod C and the nut d. It is similar to the above device in that the threaded rod C and the screw rod d are subject to large wear and tear, and furthermore, since the cylinder g and the fine adjustment mechanism are connected in series, the load applying mechanism becomes longer as a whole, which causes damage to the cylinder and the screw. The rod is easily misaligned (especially since the cylinder is not fixed, so this tendency is remarkable), which is a major drawback in that accuracy deteriorates early. Also, when the initial load is set with cylinder g, there is no impact load on the load cell. In addition, this impact load exceeds the breaking load of the load cell and has the disadvantage of destroying the load cell, so it is hardly used at present.

The present invention eliminates the above-mentioned drawbacks, and aims to provide a load applying device that takes a very short time to apply a load, has high precision, and has excellent durability.

Next, one embodiment of the present invention will be described in detail based on the drawings.

Figure 1 shows an overview of the tire uniformity testing device, which includes a rotatable lower rim 3 that is moved up and down by a hydraulic cylinder 2 installed on the base 1a of the frame 1, and a lower rim 3 that is held on the upper frame 1b of the frame. An inflated tire 6 is held between an upper rim 5 provided opposite the lower rim 3 via a rotating shaft 4.

The tire 6 is attached to the rotating shaft 4 via a chain or belt 7.
The upper rim 5 is rotated by driving the upper rim 5 with a motor 8 connected to the upper rim 5.

The load applying device has a drum 9 that applies a load to the tire 6.

This drum 9 is held by a drum holder 12 via a shaft 10 that rotatably supports it and load cells 11, 11'.

The drum holder 12 is slidably supported by a guide rod 14 attached to the upper frame 1b of the frame 1 via a bracket 13, 13' via bearings is, is'.

A piston rod 19.19' of a fluid cylinder 18.18' is connected to the drum holder 12 through a connector 17.17' on its rear side, as shown in FIG.

This fluid cylinder 18,18' is connected to the vertical frame 1 of the frame.
c, and is connected to the fluid piping 21, a solenoid valve 22, a pressure gauge 23, a pressure reducing valve 24, and a safety valve 25 provided on the fluid piping, and is connected to a predetermined pressure that is regulated by operating the pressure reducing valve 24. Driven by fluid.

The fluid cylinder 19. is mounted on the back side of the drum holder 12.
A positioning mechanism P located between 19' is connected in parallel with the fluid cylinder.

The positioning mechanism P includes a bearing box 28 fixed to the vertical frame 1c of the frame.

Inside this bearing box 28, radial bearings 30a, 30 are fixed in the axial direction by pressers 29a, 29b.
b and 30c, and a sleeve nut 33 is supported by these radial bearings.

A sprocket 32 is fixed to the rear part of this sleeve nut 33 via a key 31.

A hollow screw 35 for positioning is screwed into the inner periphery of the sleeve nut 33.

This hollow screw 35 has a flange 35a at its rear end.

A stopper rod 27 is inserted into the inner periphery of the hollow screw 35.

This stopper rod 27 is slidable in the axial direction of the hollow screw 35, and the key 34 fixed to the stopper rod 27 is fitted into a groove (not shown) on the inner periphery of the hollow screw 35 to prevent the hollow screw 35 from being screwed. 35 rotation is regulated.

The front end of the stopper rod 27 is fixed to the drum holder 12 via a connector 26, and the rear end is provided with a flange-shaped locking portion 27a.

The protrusion 33a on the outer circumference of the sleeve nut 33 is fitted between the bearings 30b and 30c and is fixed in the axial direction, while the hollow screw 35 is moved in the axial direction by the rotation of the sleeve nut 33. be done.

The flange 35a of the hollow screw 35 is connected to the sleeve nut 3.
The locking portion 27a of the stopper rod touches the end of the flange 3 of the hollow screw 35 to define the limit of axial movement.
5a to determine the stroke of the stopper rod 27.

The positioning mechanism P also includes a motor 36 that is controlled based on signals from the load cells 11, 11'.

This motor 36 is connected to the sprocket 32 of the sleeve nut 33 by a chain 37, etc., and rotates the sleeve nut 33 forward or backward depending on the fluctuation value of the load applied to the tire detected by the load cells 11, 11'. ,
or cause it to stop.

Next, the operation will be explained based on the above-mentioned configuration.

Prior to supplying fluid to the fluid cylinders 18, 18', the pressure is adjusted by the pressure reducing valve 24 so that the cylinder force is set to be greater than the tire load setting value.

For example, if the set value is 400 to 9, the pressure reducing valve 24 is adjusted so that the cylinder force is about 450 to 600 to 9.

Fluid is then supplied to the fluid cylinders 18, 18' to advance the drum holder 12.

The locking portion 27a of the stopper rod 27 connected to the drum holder hits the flange 35a of the positioning hollow screw 35 whose position has been set in advance, and at the same time, the forward movement of the drum holder is stopped. The outer peripheral surface of the drum is pressed against the outer peripheral surface of the tire 6.

Here, the tire testing machine continuously tests tires of the same size produced on one line.
The position of the hollow screw 35 is set in advance based on standard values for tires of the same size.

In other words, if the load setting value is 400 hours, a load of 400 kg will be applied to a standard size tire.
In other words, if the cylinder weighs 450 to 600 kg, 50 to 2
00kg is received by the flange 35a of the hollow screw 35 and the locking part 27a of the stopper rod 27.
Set position 5.

However, even with tires of the same size, there is some variation in the outer diameter (±
If the tire is changed, the load will vary (about ±30 kg) based on the above error, and the actual load applied to the tire will be, for example, 400 ±30 kg.

If this variable value exists, it is detected by the load cell 11.11', and the detected value is compared with a standard value stored in a storage device (not shown), that is, a set value, and the difference between the detected load and the set value is compared. The motor 36 is rotated based on the difference, and the motor 36 is rotated via the sprocket 32 to the sleeve nut 33.
, and move the hollow screw 35 a little in the axial direction to define the stroke end of the drum holder 12.
As a result of adjusting the position, the fluctuation value (±30 kg) is corrected, and a predetermined set load is applied to the tire 6.

When the load setting is completed, the load cells 11, 11' and the motor 36
Turn off the electrical connection between the tires, rotate the tire, and perform a uniformity test using a well-known method.

According to the device configured as described above, the fluid cylinder 1
8. In parallel with 18', there is provided a stopper rod 27 and a positioning mechanism P having a hollow screw 35 that locks the stopper rod at a predetermined position, so the position of the hollow screw 35 can be set in advance according to the tire size. Hollow screw 3 based on the actual load detected by the load cell.
The load can be set by finely adjusting the position of 5, and therefore the amount of adjustment by the hollow screw is only a small amount of variation in the load, so the pressing speed is much faster than in the past.

Furthermore, the load applied from the stopper rod 27 to the hollow screw 35 is the difference between the cylinder force W1 and the tire load W2 (wt - W
2), the load on the positioning mechanism can be significantly reduced compared to the conventional method in which the entire tire load W2 is applied, and therefore there is less damage to the threads of the hollow screw 35 and sleeve nut 33, and high accuracy is maintained over a long period of time. As well as being able to
There is an advantage that the positioning mechanism P can also be downsized and the output of the motor 36 can also be small.

Furthermore, when the cylinder 18.18' moves the drum 9 forward, the locking part 27a of the stopper rod 27 comes into contact with the flange 35a of the hollow screw 35, thereby restricting the drum 9 from moving forward. There is no risk that an impact load due to advancing the drum 9 will be applied to the load cell, and breakage of the load cell can be effectively prevented.

As described above, according to the present invention, drum pressing can shorten the operation time and improve tire production efficiency, and since the load applied to the positioning mechanism is small, there is less damage to threads and other parts, and it can be used for a long time. In addition to maintaining high accuracy, there are various effects such as effectively preventing the load detection load cell from being destroyed.

[Brief explanation of drawings]

Fig. 1 is a side view of a tire testing machine equipped with a load applying device according to the present invention, Fig. 2 is a longitudinal cross-sectional side view of the main parts of the same, and Fig. 3 A90 is a schematic explanatory diagram showing two sides of the conventional device. It is. 6... Tire, 9... Drum, 11,
11'...Load cell, 12...Drum holder, 14...Guide rod, 18.18
'...Fluid cylinder, 19°19...
Piston rod, P...Positioning mechanism, 27.
... Stopper rod, 27a ... Locking part, 28 ... Bearing is box, 32 ... Sprocket, 33 ... Sleeve nut, 35 ...
...Hollow screw, 36...Motor.

Claims (1)

[Claims] 1. A drum holder that supports a drum via a load cell and is supported by a frame so as to be able to move forward and backward toward the tires; a fluid cylinder that is fixed to the frame and has a piston rod connected to the drum holder; and a fluid cylinder that is connected in parallel with the fluid cylinder. a positioning mechanism attached to the frame,
The positioning mechanism includes a sleeve nut that is rotatably supported by the single flange, a hollow screw that is screwed into the inner periphery of the sleeve nut, and a hollow screw that slides only in the axial direction on the flesh layer of the hollow screw. a stopper rod that is fitted and connected to the drum holder at one end and has a locking portion at the other end that locks to the curved hollow screw, and the sleeve nut is controlled based on a detection signal from the Ronido cell A load applying device for a tire testing machine, characterized in that it consists of a motor that drives a motor.