JP5780994B2 - Multi-force measuring spindle unit for tire testing machine - Google Patents

Description

  The present invention relates to a multi-component force measuring spindle unit capable of measuring a rolling resistance of a tire.

  In general, a tire testing machine is known as a device that creates a simulated contact state between a tire and a road surface and dynamically measures the force and moment that the tire receives from the road surface. In this tire testing machine, a tire supported on a spindle shaft of a spindle unit is grounded to a rotating drum or the like serving as a road surface with a predetermined load, and a force (load) in each direction acting on the rotating tire from the rotating drum or the like. And moment are measured by a multi-component force meter built into the spindle unit.

  For example, when the tire pressing direction on the rotating drum is the z direction, the tire traveling direction (tangential direction) is the x direction, and the direction along the tire rotation axis is the y direction, the force Fz (ground contact) Load), x-direction force Fx (rolling resistance), y-direction force Fy (cornering force), z-direction moment Mz (self-aligning torque), x-direction moment A general tire testing machine can measure Mx (overturning moment), a moment My (rolling resistance moment) about an axis in the y direction, and the like.

  By the way, a strain gauge type is often used as the above-described multi-force meter. In this strain gauge type multi-force meter, for example, as shown in Patent Literature 1, an inner peripheral force applying body and an outer peripheral fixed body are interposed through a plurality of rod-shaped strain generating bodies extending in the radial direction. The force and moment acting on the tire can be measured by measuring the deformation of the strain generating body with a strain gauge.

As a tire testing machine provided with only one such multi-force meter, for example, the one shown in Patent Document 2 is known.
That is, the tire testing machine of Patent Document 2 includes a spindle that presses and contacts a test tire on the outer periphery of a traveling drum and is attached to the center of the rotation shaft of the tire and supports the tire via a bearing. Then, the tire rolling resistance measurement method is carried out by measuring the relationship between the tire axial load Fz and the rolling resistance Fx by a multi-component force detector provided at a position away from the tire by a predetermined distance of the spindle. It is. In this tire testing machine, a tire is rotatably attached via a bearing to one end of a spindle shaft that is fixed to a support frame via a force meter.

JP-A-57-169643 Japanese Patent Laid-Open No. 2003-4598

  By the way, in the tire testing machine of Patent Document 2, the spindle shaft extends from the one end portion where the tire is attached to the other end portion fixed to the support frame via a multi-force meter to some extent in the axial direction. It has a length. Naturally, when a load is applied to one end of the spindle shaft in the pressing direction, a large moment is also generated in the multi-force meter provided at the other end of the spindle shaft, so that it can withstand the large moment. Such a dynamometer will be adopted. With respect to such a multi-force meter, a thick strain body or the like is employed to withstand a large acting moment, so that even a minute force change cannot be detected, and high precision detection is sacrificed.

On the other hand, in the rolling resistance test device, it is necessary to detect a minute force change acting on the spindle shaft with high accuracy. Is desirable.
Therefore, the present inventor tried to reduce the moment applied to the multi-force meter by bringing the position of the multi-force meter closer to the tire. However, it has been found that, when the position of the multi-force meter is brought close to the tire, the influence of heat generated in the bearing portion becomes very large and the accuracy of the multi-force meter is lowered. Therefore, the present inventor provided a bearing portion in the housing on the side opposite to the tire than the multi-force meter to support the spindle shaft rotatably, and actively circulates lubricating oil in the bearing portion to actively cool the bearing portion. An attempt was made to provide a cooling mechanism. However, since the heat generated in the bearing portion is very large, the influence of the heat generated in the bearing may not be sufficiently removed even if a cooling mechanism is provided. Furthermore, it has been found that when a large amount of lubricating oil is supplied with the intention of removing heat, the lubricating oil is heated by stirring heat, and instead heat is generated at the bearing portion.

  The present inventors have further studied, and in particular, when the pressing force acts on the spindle shaft in a direction perpendicular to the shaft, heat is likely to be generated only in a part of the bearing portion supporting the spindle shaft in the circumferential direction. It has been found that a part of the circumferential direction of the housing provided with the portion is thermally deformed to a large extent in the radial direction, thereby reducing the accuracy of the multi-force meter. And knowing that the accuracy of the multimeter can be improved by cooling both the bearing and the housing over the entire circumference without actively cooling the bearing that has generated heat with lubricating oil. The present invention is achieved.

  It is an object of the present invention to provide a multi-component force measuring spindle unit for a tire testing machine that can accurately measure a force and a moment applied to a tire while suppressing thermal deformation of the housing.

In order to solve the above problems, the multi-component force measuring spindle unit of the tire testing machine of the present invention employs the following technical means.
That is, the multi-component force measuring spindle unit of the tire testing machine according to the present invention includes a spindle shaft on which a tire can be mounted, a housing that rotatably supports the spindle shaft via a bearing portion, and a tire in the axial direction of the spindle shaft. A multi-component force measuring sensor fixed to the end of the housing facing the side and capable of measuring a load acting on the spindle shaft, the multi-component force measuring sensor provided on the inner peripheral side Body, a fixed body arranged on the outer peripheral side of the force applying body, a plurality of strain generating bodies that connect the force applying body and the fixed body in the radial direction, and a strain gauge provided on the strain generating body. The bearing member is connected to the housing and the fixed body is connected to a support member, and is configured to be able to measure a rolling resistance force of a tire using the strain gauge, Cooling means for cooling the housing in the circumferential direction is provided in order to prevent the housing end on the side to which the force measuring sensor is fixed from being deformed in the radial direction due to the generated heat. It is characterized by this.

Preferably, the cooling means includes a refrigerant flow path formed along the outer circumferential surface of the housing along the circumferential direction and the axial direction of the housing, and is used for cooling along the refrigerant flow path. It is preferable that the housing is cooled by circulating the refrigerant.
Preferably, the coolant channel is formed in a spiral shape along the outer peripheral surface of the housing.

In addition, Preferably, the said refrigerant | coolant flow path is good to be arrange | positioned so that it may circulate in multiple times in a spiral shape.
Preferably, the refrigerant flow path is divided into two in the front-rear direction in the axial direction of the housing, and is formed independently in the front half of the housing and the rear half of the housing. It is preferable that the front half of the housing and the rear half of the housing can be individually cooled by the flow path.
Further, the most preferable form of the multi-component force measuring spindle unit according to the present invention includes a spindle shaft on which a tire can be mounted, a housing that rotatably supports the spindle shaft via a bearing portion, and an axial direction of the spindle shaft. One multi-component force measurement sensor fixed to the end of the housing facing the tire side and capable of measuring a load acting on the spindle shaft, and the multi-component force measurement sensor is provided on the inner peripheral side An applied body, a fixed body provided on the outer peripheral side of the applied body, a plurality of strain generating bodies that connect the applied body and the fixed body in a radial direction, and a strain gauge provided on the strained body. The force body is connected to the housing and the fixed body is connected to a support member, and is configured to measure the rolling resistance of the tire using the strain gauge. Cooling means for cooling the housing in the circumferential direction is provided in order to prevent the housing end on the side on which the multi-component force measurement sensor is fixed from being deformed in the radial direction due to heat generated in the bearing portion. The cooling means includes a refrigerant flow path formed along the outer circumferential surface of the housing along the circumferential direction and the axial direction of the housing, and a cooling refrigerant along the refrigerant flow path. The refrigerant flow path is divided into two front and rear in the axial direction of the housing, and the front half of the housing and the rear half of the housing, Each of the first and second housings is formed independently and can be individually cooled by the respective refrigerant flow paths.

  According to the multiple force measuring spindle unit of the tire testing machine of the present invention, it is possible to accurately measure the force and moment applied to the tire while suppressing thermal deformation of the housing.

(A) is a front view of a tire testing machine provided with the multiple force measuring spindle unit of the present invention, and (b) is a side view of the tire testing machine. It is front sectional drawing of the multi-component force measurement spindle unit of this invention. (A) is a perspective view of a multi-force meter, (b) is a side view of a multi-force meter. It is front sectional drawing which expanded and showed the edge part by the side of the tire of the multiple force measurement spindle unit of this invention.

An embodiment of the present invention will be described with reference to the drawings. In the following description, the same parts are denoted by the same reference numerals. Their names and functions are also the same. Therefore, detailed description thereof will not be repeated.
1A and 1B schematically show a tire testing machine 2 provided with a multi-component force measuring spindle unit 1 according to the present embodiment.

  The tire testing machine 2 includes a cylindrical rotating drum 3 that is rotated by a motor or the like. The tire testing machine 2 also includes a spindle shaft 4 to which the tire T is attached, and a multi-component force measuring spindle unit 1 that rotatably supports the spindle shaft 4 and measures a load and a moment. In the tire testing machine 2 described above, the tire T attached to the spindle shaft 4 is brought into contact with the rotating drum 3 so that the dynamic characteristics of the tire T in the running state, such as the rolling resistance of the tire T, can be obtained. Measured.

  As schematically shown in FIG. 2, the multiple force measuring spindle unit 1 includes a cylindrical housing 6 that rotatably supports the spindle shaft 4 described above via a bearing portion 5. A cylindrical hole coaxial with the housing 6 is formed outside the housing 6 and a support frame 7 (support member) for supporting the multi-component force measuring spindle unit 1 is provided. Further, in the multi-component force measuring spindle unit 1, a multi-component force measuring sensor 9 is fixed to the end of the housing 6 facing the tire side in the axial direction of the spindle shaft 4. The multi-component force measuring sensor 9 is provided so as to be able to measure various loads acting on the spindle shaft via the tire T, that is, the loads acting on the support frame 7 via the housing 6.

  In the tire testing machine 2 arranged as shown in FIG. 1B, the left-right direction of the paper (the tire traveling direction x) is referred to as the left-right direction when describing the force measuring spindle unit 1. Similarly, in the tire testing machine 2 in FIG. 1B, the paper surface penetration direction (direction y along the tire axis) is referred to as the front-rear direction when the multi-component force measuring spindle unit 1 is described. Further, in the tire testing machine 2 of FIG. 1B, the vertical direction of the paper surface (the pressing direction z of the tire T against the rotating drum 3) is referred to as the vertical direction when the force measuring spindle unit 1 is described.

Next, the spindle shaft 4, the housing 6, the support frame 7, the bearing portion 5, and the multiple force measuring sensor 9 that constitute the multiple force measuring spindle unit 1 of the present invention will be described.
FIG. 2 schematically shows the multi-component force measuring spindle unit 1 of the present invention.
As shown in FIG. 2, the multi-component force measuring spindle unit 1 of the present embodiment includes a long rod-shaped spindle shaft 4 whose axis is oriented in the horizontal direction. A tire T is attached to one end side (left side in FIG. 2) of the spindle shaft 4 via a rim (not shown). The spindle shaft 4 is rotatable with respect to the housing 6.

  The housing 6 is formed in a cylindrical shape whose axis is oriented in the horizontal direction, and the above-described spindle shaft 4 is inserted into the housing 6 with the axis oriented in the horizontal direction. Between the housing 6 and the spindle shaft 4 inserted into the housing 6, a plurality of bearings (bearing portions 5) that rotatably support the spindle shaft 4 with respect to the housing 6 are provided. In other words, the multiple force measuring spindle unit 1 is provided with a plurality of bearing portions 5 arranged in the axial direction in the middle of the spindle shaft 4 in the longitudinal direction. The spindle shaft 4 is rotatably supported by the housing 6 through the plurality of bearings (bearing portions 5).

  A support frame 7 is provided on the outer peripheral side of the housing 6 as a support member that supports the housing 6 via a multi-component force measurement sensor 9 described later. The support frame 7 of the present embodiment has a housing 8 that can house the housing 6 and a cylindrical member to which the multiple force measuring sensor 9 is fixed, and a substantially plate that extends vertically and horizontally from the cylindrical member. It is comprised with the shape-shaped member. The support member may be a combination of a plurality of members as described above, or may be a single member. In the present embodiment, the accommodating portion 8 is formed as a cylindrical hole with its axis oriented in the horizontal direction so as to be coaxial with the housing 6, and the housing with the axis of the hole oriented in the horizontal direction. 6 can be accommodated.

  As shown in FIG. 2, the plurality of bearing portions 5 can receive a load in the radial direction and / or the thrust direction, and the multi-component force measuring spindle unit 1 of the present embodiment is provided with four bearing portions 5. It has been. The four bearing portions 5 are arranged side by side with a predetermined interval along the axial direction (y direction) of the spindle shaft 4, and are arranged separately on the front and rear sides of the housing 6. Between each bearing part 5, the spacer 10 which positions each bearing part 5 in the predetermined position along an axial center direction is arrange | positioned.

  As shown in an enlarged view in FIG. 4, an air pipe 11 is provided on the front end side of the housing 6 and the support frame 7 described above so as to penetrate the support frame 7 and the housing 6 in the radial direction from the outside of the support frame 7. ing. Further, a non-contact seal 12 (labyrinth seal) that seals the lubricating oil without contacting the surface of the spindle shaft 4 is provided on the rear end side in the axial direction from the air pipe 11. By providing the non-contact seal 12, it is possible to eliminate a measurement error caused by a change in seal resistance accompanying a change in temperature of the seal portion as in the case of using a contact seal. Further, a non-contact seal 12 (labyrinth seal) having the same function and effect is also provided on the rear end side of the housing 6. The air pipe 11 guides high-pressure air from the outside of the support frame 7 between the spindle shaft 4 and the housing 6, and causes the high-pressure air to act on the non-contact seal 12. The action of the high pressure air and the non-contact seal 12 prevents the lubricating oil supplied to the bearing portion 5 from leaking outside.

  Although not shown, the multi-component force measuring spindle unit 1 is connected to an oil recovery path for recovering the lubricating oil supplied to the bearing portion 5 and an unillustrated suction means that operates as necessary. An oil recovery path 26 as shown in FIGS. 2 and 4 for recovering the lubricating oil that has leaked unintentionally from the non-contact seal 12 may be provided. In addition, an air pipe, a suction means, and an oil recovery path 26 having the same effects as described above are provided on the rear end side of the housing further than the non-contact seal (labyrinth seal) provided on the rear end side of the housing 6. Needless to say.

FIG. 4 is an enlarged view of the cross-sectional structure of the front portion (tire side) of the multi-component force measuring spindle unit 1.
Between the front end surface of the housing 6 and the front end surface of the support frame 7 described above, one multi-component force measurement sensor 9 (load cell) is provided so as to straddle both surfaces. Specifically, a force measuring sensor 9 is provided between the front end surface of the housing 6 and the front end surface of the support frame 7 so as to connect both members.

As shown in FIG. 3A, the multi-component force measuring sensor 9 of the present embodiment has a substantially disk-like appearance, and is provided one by one for one multi-component force measuring spindle unit 1. It is comprised from the attachment body 13, the fixed body 14, and the strain body 15 which connects both these.
The multi-component force sensor 9 has a ring-shaped force body 13 at the center thereof. The spindle shaft 4 passes through the center of the opening of the force applying member 13 formed in the ring shape in a loosely fitted state.

  A ring-shaped fixed body 14 having an inner diameter larger than the outer diameter of the force applying body 13 is arranged on the outer side of the force applying body 13. The force applying body 13 and the fixed body 14 are arranged so as to be coaxial with each other, and the inner peripheral force applying body 13 and the outer peripheral fixed body 14 are radially connected by a plurality of strain generating bodies 15. ing. In the multi-component force measuring sensor 9 of the present embodiment, these strain generating bodies 15 are formed in the shape of square bars that extend radially from the force applying body 13 in the four directions of upper, left, lower, and right. And four are provided around the axis of the spindle shaft 4.

  The force applying member 13 of the force measuring sensor 9 and the front end surface of the housing 6 described above are firmly fixed by a fastener (not shown) such as a bolt, and transmitted in the order of the spindle shaft 4 → the bearing portion 5 → the housing 6. The transmitted force can be transmitted to the force applying body 13. Further, a fastener (not shown) such as a bolt is also provided between the fixed body 14 of the force measuring sensor 9 and the front end surface of the support frame 7, both of which are firmly coupled to each other, and the spindle shaft 4. The force transmitted to the support frame 7 (various loads acting on the tire) can be measured by the strain generated in the strain body 15 provided in the middle of the transmission path.

  As shown in FIG. 3A, each strain body 15 is provided with a thin portion having a small thickness, and when a force acts between the force applying body 13 and the fixed body 14, the thin wall portion is provided. The strain body 15 is deformed starting from the portion. In addition, a strain gauge 16 capable of detecting a force and a moment is attached to each strain generating body 15. The strain gauge 16 includes a strain gauge 16 that is attached to the side close to the force applying body 13 and measures a translational load, and a strain gauge 16 that is attached to the side close to the fixed body 14 and measures a moment.

That is, in the multi-component force measuring spindle unit 1 of the present invention, the multi-component force measuring sensor 9 disposed at the end of the housing 6 (support frame 7) on the tire side is used to translate the load in the x, y, and x directions ( fx, fy, fz) and six component forces of the moments (mx, my, mz) around the x-axis, y-axis, and z-axis can be measured.
As shown in FIG. 3A and FIG. 3B, in the load cell 9 of this embodiment, the thickness of the strain generating body 15 is formed to be equal, but in particular, the rolling resistance is within the above-described six component forces. Since fx is important in evaluating the characteristics of the tire T, in the multi-component force measuring spindle unit 1 according to the present invention, the thin portion of the strain body 15 extending in the left-right direction extends from the thin portion of the strain body 15 extending in the vertical direction. You may form thinner (thinner) than a part. In this way, the strain body 15 extending in the vertical direction is more easily deformed even when a small load is applied in the x direction, compared to the case where all the strain body 15 is formed to be the same and thick as in the prior art. The rolling resistance fx can be measured with high sensitivity. That is, in the multi-component force measuring spindle unit 1 of the present invention, it is possible to adopt a high-sensitivity thin strain-generating body to provide a test apparatus suitable for measuring tire rolling resistance with high sensitivity.

The analog signal measured by the strain gauge 16 of the strain generating body 15 in this way is input to an amplifier (not shown) disposed near the load cell 16 so as not to be subjected to noise, and is amplified and A / D converted. The processing unit (personal computer) built in the amplifier is calibrated using a calibration expression such as a calibration matrix, and the rolling resistance fx and the like are calculated.
By the way, in the tire testing machine of Patent Document 2 described above, the spindle shaft (5: the reference numerals in parentheses are shown with reference to the reference numerals in Patent Document 2) has a certain length in the axial direction. Therefore, when a load is applied to one end of the spindle shaft (5) in the pressing direction (axis perpendicular direction) and an attempt is made to measure force, moment, etc. at the other end of the spindle shaft (5), A large moment acts on the multi-force measuring sensor (4). Therefore, for the multi-component force measurement sensor (4) used in such a tire testing machine, a thick strain body is employed to withstand a large acting moment, and even a minute force change cannot be detected and detection accuracy is high. Was sacrificed.

  In order to avoid such a difficulty, the position of the force measuring sensor (4) can be brought closer to the tire T and the moment applied to the force meter can be reduced. When approaching the tire provided with the bearing portion (10), the heat generated in the bearing portion (10) and the thermal deformation associated therewith lowers the accuracy of the force sensor. As shown in the drawing of the present embodiment, in order to reduce the moment applied to the multi-force meter 9, a plurality of bearings are provided in the housing 6 on the side opposite to the tire than the multi-force meter 9, so that the spindle shaft 4 can rotate freely. A cooling mechanism that actively supports and cools the bearing portion 5 by circulating the lubricating oil of the bearing portion 5 can be provided separately. However, since the heat generated in the bearing portion is very large, the cooling mechanism is It has been found through experiments that even if it is provided, heat generated by the bearing (particularly heat generated by the bearing close to the tire) may not be sufficiently removed. Further, it has been found through experiments that when a large amount of lubricating oil is supplied with the intention of removing heat, the lubricating oil is heated by stirring heat and heat may be generated in the bearing portion 5 instead.

  Furthermore, when a pressing force is applied to the spindle shaft 4 in a direction perpendicular to the shaft, heat is likely to be generated only in a part of the bearing portion 5 supporting the spindle shaft 4 in the circumferential direction. The heat generated in only a part of the heat is caused to cause a large amount of heat deformation (particularly radial deformation) in the circumferential direction of both the bearing portion 5 and the housing 6 that covers the bearing portion 5, so that the force meter Will reduce the accuracy.

Therefore, in the multi-component force measuring spindle unit 1 of the present invention, the housing 6 is arranged in the circumferential direction in order to prevent a part of the circumferential direction of the housing 6 from being deformed in the radial direction due to heat generated in the bearing portion 5. Cooling means 17 is provided for cooling over.
Specifically, as shown in FIG. 2, the cooling means 17 is configured to send the refrigerant from the outside to the housing 6 and directly cool the housing 6 from the inside. The refrigerant spirally extends around the refrigerant flow path 18 formed along the outer circumferential surface of the housing 6 along the circumferential direction and the axial direction of the housing 6, more specifically, around the axis of the housing 6. The refrigerant flows through the refrigerant flow path 18 formed so as to circulate, and cools the housing 6 so that the temperature is as uniform as possible in the circumferential direction and the axial direction.

Hereinafter, the cooling means 17 of this embodiment and the refrigerant flow path 18 which comprises this cooling means 17 are demonstrated.
As shown in FIG. 2, in the multi-component force measuring spindle unit 1 of the present embodiment, the housing 6 has a structure including a refrigerant flow path 18 of another system before and after the installation length becomes substantially the same in the axial direction.

That is, the refrigerant flow path 18 described above is formed independently on both the front side (housing front half) 6F of the housing and the rear side (housing rear half) 6R of the housing.
For example, in the front half of the housing (hereinafter simply referred to as the front half) 6F, a spiral groove 18F is formed around the outer peripheral surface along the axial direction (from the front end side to the rear end side of the front half 6F). Yes. The spiral groove 18F is continuously formed as a single line without intersecting from the front end side to the rear end side of the front half portion 6F. ing. In addition, the spiral groove 18F that forms the coolant channel 18 is not limited to one, but may be two or more. In addition, the refrigerant flow path 18 can be any one that cools the housing 6 in the circumferential direction so as to prevent the housing end on the side where the force measurement sensor is fixed from being deformed in the radial direction by heat. Although it may be provided at any position along the outer peripheral surface, it is preferably formed at a position covering at least the bearing portion 5 provided in the front half 6F, and the front half 6F and the housing rear half 6R ( Hereinafter, it is more preferably formed in a separate system at a position covering the bearing portion 5 provided in the second half portion. Furthermore, it is more preferable that the refrigerant flow paths 18 formed in separate systems in the first half 6F and the second half 6R are formed over substantially the entire axial direction of the corresponding first half 6F and second half 6R, respectively. Thus, the refrigerant flow path 18 is formed over substantially the entire area of the housing 6 in the axial direction.

  One end (front end) of the refrigerant flow path 18 formed on the outer peripheral surface of the front half 6F is connected to a communication flow path (first communication flow path 19) that communicates with the inside of the front half 6F. The communication channel 19 is formed along the axial direction inside the peripheral wall of the front half 6 </ b> F, and is connected to the outside of the housing 6. Similarly, the other end (rear end) of the refrigerant flow path 18 of the front half 6F is connected to a communication flow path (second communication flow path 20) that communicates with the inside of the front half 6F. The second communication channel 20 is a channel different from the first communication channel 19, is formed along the axial direction inside the peripheral wall of the front half 6 </ b> F, and is connected to the outside of the housing 6. It has become.

  After the refrigerant introduced through the first communication channel 19 reaches the front end of the refrigerant channel 18 (18F), the refrigerant circulates in the vicinity of the surface of the front half 6F while flowing through the refrigerant channel 18 (18F). The front half 6F is cooled in the circumferential direction from the outer peripheral surface side. The refrigerant that has reached the rear end of the refrigerant flow path 18 (18F) is discharged to the outside of the housing 6 through the second communication flow path 20. The direction in which the refrigerant is introduced may be the reverse flow, that is, the second communication channel 20 → the refrigerant channel 18 → the first communication channel 19.

On the other hand, the configuration of the refrigerant flow path 18 formed on the outer peripheral surface of the rear half 6R and the refrigerant distribution mode are substantially the same as in the case of the front half 6F.
That is, in the rear half portion 6R, a spiral groove 18R is formed along the outer peripheral surface from the rear end side to the front end side of the rear half portion 6R. The single spiral groove 18R serves as the refrigerant flow path 18 described above. The front end and the rear end of the refrigerant channel 18 (18R) formed on the outer peripheral surface side of the rear half 6R are communication channels (third communication channel 21 and fourth communication channel) that communicate with the inside of the peripheral wall of the rear half 6R. 22), it is connected to the outside of the housing 6.

  The refrigerant introduced through the third communication flow path 21 reaches the rear end of the refrigerant flow path 18 (18R) and then circulates in the vicinity of the surface of the rear half 6R while flowing through the refrigerant flow path 18 to the outer peripheral surface side. Then, the latter half 6R is cooled in the circumferential direction. The refrigerant that has reached the front end of the refrigerant flow path 18 (18R) is discharged to the outside of the housing 6 through the fourth communication flow path 22. The direction of introduction of the refrigerant may be the reverse of the above.

In order to form the spiral refrigerant flow path 18 (18F, 18R) as described above on the outer peripheral surface of the housing 6, for example, the following processing may be performed.
That is, as shown in FIG. 4, the above-described housing 6 may be constituted by a cylindrical housing body 24 and a cylindrical and thin outer shell body 25 that covers the housing body 24. Then, a spirally-circular groove is machined along the axial direction on the outer peripheral surface of the housing body 24. The width, depth, pitch, and the like of the groove to be processed at this time can be appropriately changed according to the size of the housing 6 and the cooling capacity. Thereafter, the outer shell 25 is fitted into the housing body 24, and the opening of the groove is covered with the outer shell 25. At that time, if necessary, a seal member for sealing both ends of the housing main body 24 and the outer shell body 25 may be provided, and the outer shell body 25 is welded to the housing main body 24 and both end portions thereof are welded. May be sealed. By doing in this way, the refrigerant flow path 18 can be formed along the outer peripheral surface of the housing 6 (more precisely, the inside immediately under the surface).

Further, as the refrigerant flowing through the refrigerant flow path 18, an organic compound coolant such as alternative chlorofluorocarbon can be used. Instead of the organic compound coolant, water or oil may be used. This refrigerant is cooled by a cooling device (not shown) provided outside the tire testing machine 2 and supplied to the refrigerant flow path 18.
As described above, the housing 6 is provided with means for cooling the housing 6 in the circumferential direction so as to prevent the end portion on the side to which the force measuring sensor 9 is fixed from being deformed in the radial direction. . More specifically, the housing 6 is formed so that the refrigerant flow path 18 is formed in the housing 6 at least in the circumferential direction and the axial direction of the front half of the housing on the side where the force sensor 9 is fixed. It is arranged so as to circulate a plurality of times spirally along the outer peripheral surface. By circulating the refrigerant through such a refrigerant flow path, it is possible to suppress temperature unevenness in the circumferential direction at the end of the housing 6 on the side where the force sensor 9 is fixed at least. As a result, at the end of the housing 6 on the side where the force measuring sensor 9 is fixed, only a part in the circumferential direction is not hotter than other parts (a large temperature difference in the circumferential direction), and maybe Only a part in the circumferential direction of the housing 6 on the side where the force measuring sensor 9 is fixed does not extend in the radial direction. In other words, the error component due to the difference in elongation does not act on the multiple force measuring sensor 9 connected to the housing 6. Therefore, the accuracy of the force measuring sensor 9 is not lowered due to the distortion of the housing end due to the heat generated in the bearing portion 5.

Furthermore, if the refrigerant flow path 18 that circulates a plurality of times in a spiral shape is provided over substantially the entire axial direction of the housing 6, and the refrigerant flows through the refrigerant flow path 18, the housing 6 is moved in the circumferential direction. And it becomes possible to cool uniformly in the whole area over the axial direction. As a result, the distortion of the housing 6 due to the heat generated in the bearing portion 5 can be more reliably suppressed.
In addition, if the refrigerant flow path 18 is divided into the housing front half 6F and the housing rear half 6R in the axial direction and the refrigerant is individually supplied to the independent refrigerant flow paths 18, the housing 6 The housing front half 6F and the housing rear half 6R can be cooled independently according to the heat generation situation. For example, depending on the distribution of the force applied to the spindle shaft 4 and the arrangement of the bearing portion 5, there may be a case where the front portion of the housing generates heat more than the rear portion of the housing. In such a case, the front part of the housing 6 that generates a large amount of heat is effectively obtained by making the flow rate of the refrigerant flowing through the front part (front half part 6F) of the housing larger than that of the rear part (second half part 6R) of the housing. Therefore, it is possible to more surely prevent a decrease in accuracy of the force meter.

  The embodiment disclosed this time should be considered as illustrative in all points and not restrictive. For example, in the embodiment disclosed this time, a tire testing machine using a rotating drum is illustrated, but the present invention is not limited thereto. In particular, in the embodiment disclosed this time, matters that are not explicitly disclosed, for example, operating conditions and operating conditions, various parameters, dimensions, weights, volumes, and the like of a component deviate from a range that a person skilled in the art normally performs. Instead, values that can be easily assumed by those skilled in the art are employed.

In addition, when providing the bearing part 5 mentioned above, it is desirable to apply an appropriate preload to the two front and rear bearing parts 5 in the axial direction using a bearing nut or the like. By applying an appropriate preload in this way, it is possible to prevent a gap from being formed between the rolling elements of the bearing portion 5 and the rolling surface, and it is difficult for deformation of the rolling elements to occur, thereby reducing the heat generation of the bearing portion 5. Because it can be fastened.
The multi-component force measuring sensor 9 described above may be other than the six-component force meter, that is, a three-component force meter or a five-component force meter. In the embodiment disclosed this time, the seal of the shaft portion on the rear side of the housing is not particularly described, but a non-contact seal (labyrinth seal) similar to the shaft seal on the rear side of the housing can be provided. In this way, it is possible to eliminate measurement errors caused by a change in seal resistance accompanying a change in temperature of the seal portion on the rear side of the housing.

  Further, the supply of the refrigerant to the refrigerant flow path 18 may be performed by a pipe line connected to the outer peripheral side of the housing 6. In that case, it is desirable to provide a refrigerant supply conduit so as to penetrate the support frame 7 in a non-contact state in the radial direction. Similarly, the discharge of the refrigerant from the refrigerant flow path 18 may be performed by a pipe line connected to the outer peripheral side of the housing 6. In that case, it is desirable to provide a refrigerant discharge conduit so that the outer sleeve 7 is in a non-contact state. By providing the pipe line in this way, it becomes easier to cool the temperature in the circumferential direction of the housing 6 more uniformly than forming the flow path inside the housing.

DESCRIPTION OF SYMBOLS 1 Multicomponent force measuring spindle unit 2 Tire testing machine 3 Rotating drum 4 Spindle shaft 5 Bearing part 6 Housing 6F housing front half part 6R housing latter half part 7 Support frame (support member)
DESCRIPTION OF SYMBOLS 8 Accommodating part 9 Multi-component force measurement sensor 10 Spacer 11 Air piping 12 Non-contact seal 13 Forced body 14 Fixed body 15 Strain body 16 Strain gauge 17 Cooling means 18 Refrigerant channel 19 First communication channel 20 Second communication channel 21 Third communication channel 22 Fourth communication channel 24 Housing body 25 Outer shell T Tire

Claims (3)

A spindle shaft on which a tire can be mounted, a housing that rotatably supports the spindle shaft via a bearing portion, and a spindle shaft that is fixed to the end of the housing facing the tire side in the axial direction of the spindle shaft and the spindle shaft One multi-component force measurement sensor capable of measuring the load acting on
The multi-component force measuring sensor includes an applied force body provided on an inner peripheral side, a fixed body provided on the outer peripheral side of the applied body, and a plurality of strain generating bodies that connect the applied body and the fixed body in a radial direction. And a strain gauge provided in the strain body,
The force applying body is connected to the housing and the fixed body is connected to a support member, and is configured to be able to measure the rolling resistance force of the tire using the strain gauge.
Cooling means for cooling the housing in the circumferential direction in order to prevent the housing end on the side to which the multiple force measurement sensor is fixed from being deformed in the radial direction due to the heat generated in the bearing portion. Provided ,
The cooling means includes a refrigerant flow path formed along the outer circumferential surface of the housing along the circumferential direction and the axial direction of the housing, and causes the cooling refrigerant to flow along the refrigerant flow path. And is configured to cool the housing,
The refrigerant flow path is divided into two in the front-rear direction in the axial direction of the housing, and is formed independently in the front half of the housing and the rear half of the housing. A multi-component force measuring spindle unit for a tire testing machine, wherein the front half and the rear half of the housing can be individually cooled . The multi-component force measuring spindle unit of the tire testing machine according to claim 1 , wherein the refrigerant flow path is formed in a spiral shape along the outer peripheral surface of the housing. The multi-component force measuring spindle unit of the tire testing machine according to claim 2 , wherein the refrigerant flow path is arranged so as to circulate a plurality of times spirally.