JP4265779B2 - Tire testing machine - Google Patents

Description

  The present invention relates to a tire testing machine used for measuring tire uniformity.

A tire testing machine used for measuring tire uniformity (static or dynamic characteristics of a tire) includes a spindle device that holds a test tire in a state of being inflated at a predetermined internal pressure, and a spindle device. A drum device that transmits a rotational force by bringing the drum into contact with the outer peripheral surface of the test tire to be held (for example, see Patent Document 1)
The spindle device includes a pair of rims that are in contact with the bead portions on both sides of the test tire, and a pair of spindles that support the rims at their respective rotation centers. In many cases, these spindles are arranged in an up-and-down manner. Of these, for example, the lower spindle is rotatably held by a cylindrical bearing housing, and this bearing housing has a cylindrical portion having a larger diameter. The spindle base is held in an outer fitting shape.

The bearing housing is provided with a flange so as to protrude from the upper surface of the spindle base, and a preload bolt is tightened from the flange toward the upper surface of the spindle base so as to be parallel to the rotation axis of the test tire. And the spindle base are fixed. The top surface of the spindle base is provided with a donut-shaped detector (a load detector such as a piezoelectric element) that is penetrated in a skewered manner by a preload bolt. By this detector, the radial direction from the test tire is measured. Loads generated in three directions, axial and tangential, are each measured via a bearing housing.
Japanese Utility Model Publication No. 6-45239

When the spindle rotates at a high speed, the bearing housing that supports the rotation of the spindle generates frictional heat from the bearings and stirring heat from the lubricating oil, and this thermal effect is derived to both the detector and the preload bolt. .
However, because these detectors and preload bolts have different coefficients of thermal expansion and longitudinal elasticity, there is a difference in expansion and contraction length due to thermal effects, which causes measurement errors as temperature drift in the measured values of the detectors. become. Such temperature drift can be dealt with by measuring the amount of change thereafter by correcting the error on the charge amplifier side of the detector (that is, setting the state where the temperature drift has occurred to an initial value “0”). When the true value from the absolute value is required, as in the case of calculating the deviation value of the spring force on the test tire side with respect to the pressing force, there is a problem that the measurement accuracy is poor as it is. there were.

In the conventional tire testing machine (Patent Document 1) described above, a refrigerant passage is provided in a position inside the bearing housing and in the vicinity of the bearing portion, and water serving as a refrigerant is supplied into the refrigerant passage. However, since the specific heat and mass of the bearing housing are much larger than that of this refrigerant, the bearing housing tends to increase in temperature with the lapse of time. There was a case.
For this reason, although a partial cooling action is expected around the refrigerant passage and around the lubricating oil supply path, flowing heat to the outside of the bearing housing occurs at a part away from the refrigerant passage and the lubricating oil supply path. As a result, the temperature distribution was not uniform, and it was difficult to control the temperature of the detector.

In addition, because the driving conditions on the tire testing machine are not uniform, such as high-speed driving and low-speed driving, long-time driving and short-time driving, etc., the temperature rise is not constant and it is difficult to predict. Therefore, temperature control for the detector was extremely difficult.
The present invention has been made in view of the above circumstances, and in measuring various tire uniformity of the test tire, the temperature effect caused by the temperature rise of the bearing housing and the like caused by driving (rotation of the test tire). It is an object of the present invention to provide a tire testing machine that is difficult to receive and that can obtain highly accurate measurement results.

In order to achieve the above object, the present invention has taken the following measures.
That is, the tire testing machine according to the present invention includes a spindle device that rotatably holds a test tire in a state inflated with a predetermined internal pressure, and a drum that abuts the outer peripheral surface of the test tire held by the spindle device. And a drum device for transmitting the rotational force. Further, a detector capable of measuring the load generated from the test tire with respect to the spindle device is provided.
The detector is fixed to the spindle device in a state in which a preload is applied by tightening a preload bolt inserted through an attachment hole provided through the central portion. Also, the preload bolts that attach the detectors to the spindle device is provided with a refrigerant passage which has a hollow portion passing through the mounting hole of at least the detector, the refrigerant is capable supplied to the refrigerant passage.

  Thus, the preload bolt for attaching the detector to the spindle device is made hollow, and this hollow portion is used as a refrigerant passage (that is, the refrigerant is supplied to the hollow portion), so that the preload bolt itself is directly attached. Can be cooled. Since the preload bolt itself has a smaller mass than a bearing housing or the like, and therefore has a small heat capacity, temperature control can be performed relatively easily. The detector can be temperature-controlled (temperature correction) via the preload bolt without being affected by the temperature of the bearing housing or the like.

It is preferable to provide a temperature sensor in the refrigerant passage of the preload bolt. This temperature sensor is electrically connected to a temperature control unit capable of controlling the temperature of the refrigerant supplied to the refrigerant passage of the preload bolt. As a result, the refrigerant itself can be feedback controlled with the refrigerant temperature detected by the temperature sensor. As a result, the temperature control becomes direct and the accuracy can be further improved.
In addition, it has been proposed that the spindle device is provided with a refrigerant passage on the device side so as to pass through the vicinity of the bearing portion (see, for example, Patent Document 1). Therefore, when this apparatus-side refrigerant passage is provided, an apparatus-side temperature sensor is provided in the vicinity of the detector, and this apparatus-side temperature sensor is also electrically connected to the above-described temperature control unit. It is preferable.

In this way, in this temperature control unit, based on the difference between the temperature data obtained by the temperature sensor in the preload bolt and the temperature data obtained by the device side temperature sensor, the refrigerant to the refrigerant passage in the preload bolt Alternatively, the temperature of at least one of the refrigerants to the apparatus-side refrigerant passage can be controlled. By doing in this way, the precision of temperature control can be raised further.
The refrigerant supplied to the refrigerant passage in the preload bolt can be a gas. In this case, the refrigerant passage may be provided with an air release portion on the downstream side thereof. On the other hand, the refrigerant can be a liquid, and in this case, the refrigerant passage communicates the downstream side with the refrigerant recovery passage as appropriate, and the refrigerant recovery passage communicates with the upstream side of the refrigerant passage. A circulation path may be formed as follows.

  In the tire testing machine according to the present invention, it becomes difficult to be affected by temperature due to the temperature rise of the bearing housing or the like caused by operation (rotation of the test tire), and as a result, a highly accurate measurement result can be obtained. become.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
1 to 4 show an embodiment of a tire testing machine 1 according to the present invention. This tire testing machine 1 has a spindle device 2 that rotatably holds a test tire T in a state where it is inflated with a predetermined internal pressure. The test tire T held by the spindle device 2 is brought into contact with the outer peripheral surface (tread surface) of a drum that is driven to rotate by a drum device (not shown) to transmit the rotational force. Yes.
The spindle device 2 shown in the figure has a pair of upper and lower rims 4, 5, and both the rims 4, 5 are brought into contact with the bead portions on both sides of the test tire T, and in that state in the test tire T When the pressurized gas (air) is filled, the inflated test tire T is sandwiched between the rims 4 and 5. Each of the rims 4 and 5 is supported at the center of rotation by the upper and lower spindles 6 and 7. These rims 4 and 5 have a plurality of sizes according to the tire size of the test tire T. Are prepared, and are exchanged for one of the applicable sizes for each measurement.

The upper spindle 6 can be moved up and down by an elevating cylinder (not shown) or the like, and the lower spindle 7 stands by at a lower position. When the upper rim 4 is separated from the lower rim 5 by the upper spindle 6 rising. The test tire T can be put on and taken out from the lower rim 5, and when the upper rim 4 comes close to the lower rim 5 when the upper spindle 6 is lowered, the test tire T placed on the lower rim 5 is As described above, it is held between the upper and lower rims 4 and 5.
The upper spindle 6 is provided with a male fitting portion 10 that protrudes downward, and the lower spindle 7 is provided with a female fitting portion 11 that externally fits the male fitting portion 10. The vertical sliding of the spindles 6 and 7 is smoothly guided by rattling by mutual male-female fitting. Since the male / female fitting portion is provided with an engaging means 12 for preventing relative vertical movement as required, the male / female fitting portion moves up and down when the test tire T is inflated with pressurized gas and during the subsequent measurement. The relative separation between the rims 4 and 5 is limited.

The lower spindle 7 is fitted into a cylindrical bearing housing 15 and is rotatably held by a bearing 16 built in the bearing housing 15. The bearing housing 15 is held in an outer fitting manner by a spindle base 17 having a cylindrical portion having a larger diameter.
The bearing housing 15 is provided with a flange 20 projecting radially outward at an upper peripheral portion thereof, and the flange 20 covers the upper surface of the spindle base 17. The flange 20 is provided with bolt through holes 21 at a plurality of locations (four locations in the illustrated example) in the circumferential direction, and preload bolts 23 can be inserted into the bolt through holes 21. As is clear from FIG. 4, the preload bolt 23 has a head 24 formed in a disk shape, and a tool engagement recess 25 for engaging the rotary tool on the upper surface thereof. Therefore, the bolt through hole 21 provided in the flange 20 of the bearing housing 15 is formed with a counterbore 26 (see FIG. 3) for embedding the head portion 24 of the preload bolt 23 to a predetermined depth.

A detector 29 is provided on the upper surface of the spindle base 17 via a sensor base 28. The detector 29 is formed in a donut shape, and a mounting hole 30 through which the preload bolt 23 can be inserted is provided in the center. The sensor base 28 is provided with a female screw hole 32 for receiving the preload bolt 23. The detector 29 is, for example, a crystal type piezoelectric element, and can detect a load (three component forces) generated in three directions of a radial direction, an axial direction, and a tangential direction.
Accordingly, the sensor base 28 and the detector 29 are provided on the upper surface of the spindle base 17, and the flange 20 of the bearing housing 15 is covered on the sensor base 28 and the detector 29. The preload bolt 23 is inserted into a skewered shape, and the preload bolt 23 is further tightened into the female screw hole 32 of the sensor base 28 in the screwing direction, so that the bearing housing 15 and the spindle base 17 are fixed. Thus, a predetermined preload (longitudinal compressive force) can be applied to the detector 29.

The preload bolt 23 has a hollow axial center. On the other hand, the spindle base 17 is provided with a downstream passage 35 extending downward at a position matching the female screw hole 32 of the bearing housing 15, and the downstream passage 35 is directed radially outward near the lower portion of the spindle base 17. It is formed so as to change and escape to the outer surface.
Further, the bearing housing 15 is provided with an upstream passage 36 communicating with the counterbore 26 of the bolt through hole 21 from the side. The upstream passage 36 extends downward in the peripheral wall of the bearing housing 15 and then the downstream passage. The spindle base 17 is formed in such a manner that the direction of the spindle base 17 is changed to a radially outward position at a position different from the outer surface removal position 35 and passes through the peripheral wall of the spindle base 17 so as to exit to the outer surface. The upper part of the counterbore 26 of the bolt through hole 21 is closed by a lid 37. The lid 37 is formed so thin that it does not interfere with the communication between the counterbore 26 and the upstream passage 36.

For these reasons, when a coolant such as water or coolant oil is supplied to the upstream passage 36, the coolant passes along the upstream passage 36 through the counterbore 26 of the bolt hole 21 to the hollow portion of the preload bolt 23. Then, it flows into the outer surface of the spindle base 17 through the downstream passage 35. Therefore, at this time, the refrigerant passage 40 is formed in the hollow portion of the preload bolt 23.
Note that the refrigerant may be liquid or gas, but in the case of using gas, the position where the outer surface of the downstream passage 35 is removed may be the atmosphere opening portion. When the refrigerant is liquid, the position where the downstream passage 35 is removed from the outer surface is communicated with an appropriate refrigerant collection passage, and the refrigerant collection passage is communicated with the upstream passage 36 to form a circulation path.

A temperature sensor 41 is provided in the refrigerant passage 40 of the preload bolt 23, and the temperature sensor 41 is electrically connected to the temperature control unit 42. Therefore, the temperature of the refrigerant passing through the refrigerant passage 40 of the preload bolt 23 is monitored by the temperature control unit 42 and processed as necessary.
It is preferable to electrically connect a temperature sensor 43 provided to the spindle device 2 to the temperature controller 42. That is, the temperature near the detector 29 is detected by the device side temperature sensor 43. In this way, the difference between the temperature data obtained by the temperature sensor 41 in the preload bolt 23 and the temperature data obtained by the device-side temperature sensor 43 can be obtained, and temperature control based on this difference value. Is possible. The target of temperature control is not limited to the refrigerant supplied to the refrigerant passage 40 of the preload bolt 23, but may be the refrigerant supplied to the apparatus-side refrigerant passage if a refrigerant passage is provided on the apparatus side. .

  As is apparent from the above description, in the tire testing machine 1 according to the present invention, the preload bolt 23 for attaching the detector 29 to the spindle device 2 is made hollow, and this hollow portion is used as the refrigerant passage 40. The refrigerant supplied to the refrigerant passage 40 is appropriately adjusted in supply pressure and flow rate by a pump, and the temperature control unit 42 performs temperature management. The temperature control by the temperature control unit 42 may be control that keeps the predetermined temperature constant. However, the refrigerant itself is fed back based on the refrigerant temperature detected by the temperature sensor 41 provided in the refrigerant passage 40. It is preferable to control.

  For example, the difference between the average value of the output signal of the detector 29 and the initial reference value is obtained, and the temperature control unit 42 outputs a command signal that should eliminate this temperature drift based on the presence / absence of the temperature drift and the generated amount, A temperature control valve for adjusting the temperature of the refrigerant is controlled. When the temperature-controlled refrigerant is supplied into the refrigerant passage 40 of the preload bolt 23, the preload bolt 23 itself has a smaller mass than the bearing housing 15 or the like, and therefore has a smaller heat capacity. Since it is easy, the temperature of the detector 29 is directly and quickly controlled via the preload bolt 23, and the subsequent measurement accuracy is improved.

In the spindle device 2, for example, a coolant passage may be provided on the device side so as to pass around the mounting position of the detector 29 with respect to the spindle base 17. In this case, for example, cooled dry air is blown into the refrigerant passage on the apparatus side as a refrigerant. Therefore, the detector 29 is also cooled from the periphery via the bearing housing 15 from the spindle base 17.
The refrigerant supplied to the refrigerant passage on the apparatus side not only has an effect of cooling the detector 29 to some extent, but also into the upstream passage 36 and the downstream passage 35 communicating with the refrigerant passage 40 of the preload bolt 32 to the inside thereof. There is also an effect of cooling the supplied refrigerant. For these reasons, the temperature rise of the detector 29 is prevented as much as possible.

  Since the spindle base 17 and the bearing housing 15 are cooled by the refrigerant supplied to the refrigerant passage on the apparatus side as described above, the temperature data obtained by the temperature sensor 41 in the preload bolt 23 and the apparatus side temperature sensor 43 ( The difference from the temperature data obtained by that provided near the detector 29 tends to be narrowed. The temperature control unit 42 adopts such a difference as a temperature control element, and controls the heat exchanger (heater or cooler) provided in the refrigerant supply pump, for example. The difference between the thermal strain of the 29 itself and the thermal strain of the preload bolt 23 itself can be made minute, and the drift correction by the refrigerant can be performed accurately and quickly.

In order to correct the temperature characteristics of the charge amplifier of the detector 29, calibration is performed using a test weight or a calibration load cell before the test tire T is mounted, and the lateral load at this time is corrected. It is advisable to perform an initial setting to set the voltage to “0”, assuming that the linear characteristic is used.
By the way, this invention is not limited to the said embodiment, It can change suitably according to embodiment.
For example, the detector 29 is not limited to a quartz piezoelectric element. Further, the detailed configuration with respect to the number of the detectors 29 to be attached and the attachment position is not limited.

  In the above embodiment, the forward path for supplying the refrigerant to the refrigerant passage 40 of the preload bolt 32 is described as being directed from the upstream passage 36 to the downstream passage 35, but this may be a reverse flow. In particular, when a gas (such as air) is used as the refrigerant, it is preferable to cause an upward flow from the downstream passage 35 toward the refrigerant passage 40. When gas is used as the refrigerant in this way, the downstream passage 35 is not formed, and the cover 37 blocking the counterbore 26 of the bolt through hole 21 of the bearing housing 15 is also removed, and the open end is provided here. May be formed.

  The rims 4 and 5 may be arranged to face each other in the left-right direction. In addition, the detailed configuration of the tire testing machine itself can be changed as appropriate.

1 is a front sectional view showing an embodiment of a tire testing machine according to the present invention. It is an AA arrow directional view (plan view of a bearing housing and a spindle base) of FIG. FIG. 2 is an enlarged view of a part (around the detector) in FIG. 1. It is the perspective view which showed the preload bolt.

Explanation of symbols

T Test tire 1 Tire testing machine 2 Spindle device 23 Preload bolt 29 Detector 30 Mounting hole 40 Refrigerant passage 41 Temperature sensor 42 Temperature control unit 43 Device side temperature sensor

Claims (5)

A spindle device (2) that rotatably holds the test tire (T) in a state inflated with a predetermined internal pressure, and a drum that contacts the outer peripheral surface of the test tire (T) held by the spindle device (2) A tire testing machine provided with a detector (29) capable of measuring a load generated from the test tire (T) with respect to the spindle device (2). The detector (29) is fixed to the spindle device (2) in a state in which a preload is applied by tightening a preload bolt (23) inserted through a mounting hole (30) provided through the center of the detector (29). are, the said detector (29) has the mounting to the spindle unit (2) preload bolts (23) causes the hollow portion through the mounting hole (30) in at least the detector (29) Coolant path (40) is provided a tire testing machine, wherein a coolant is capable of supplying the refrigerant passage (40).   A temperature sensor (41) is provided in the refrigerant passage (40) of the preload bolt (23), and this temperature sensor (41) can control the temperature of the refrigerant supplied to the refrigerant passage (40) of the preload bolt (23). The tire testing machine according to claim 1, wherein the tire testing machine is electrically connected to a temperature control section (42).   The spindle device (2) is provided with a device-side temperature sensor (43) in the vicinity of the detector (29), and this device-side temperature sensor (43) is electrically connected to the temperature controller (42). The temperature control unit (42) is based on the difference in temperature data between the temperature sensor (41) provided in the refrigerant passage (40) of the preload bolt (23) and the device side temperature sensor (43). The tire according to claim 2, wherein the temperature of the refrigerant supplied to at least one of the refrigerant passage (40) in the preload bolt (23) or an appropriate refrigerant passage on the apparatus side can be controlled. testing machine.   The refrigerant supplied to the refrigerant passage (40) of the preload bolt (23) is a gas, and an atmosphere opening portion is provided on the downstream side of the refrigerant passage (40). 4. The tire testing machine according to any one of 3.   The refrigerant supplied to the refrigerant passage (40) of the preload bolt (23) is liquid, and the downstream side of the refrigerant passage (40) communicates with the upstream side of the refrigerant passage (40) via the refrigerant recovery passage. The tire testing machine according to any one of claims 1 to 3, wherein a circulation path is formed.

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