Chassis dynamometer and method of opening and closing a roller opening of chassis dynamometer

In a conventional chassis dynamometer, when a roller opening formed in a pit cover is closed by an open/close plate, the open/close plate is projected from an upper surface of the pit cover so that irregularities are generated on the upper surface of the pit cover. A chassis dynamometer 1 includes rollers 2, 3 on which wheels of a test vehicle are rested through roller openings 6, 7 formed in a pit cover 5, and an opening open/close mechanism 15 that opens and closes the roller openings 6, 7. The rollers 2, 3 are ascendably and descendably operated by a roller ascent/descent operation mechanism 8. The rollers 2, 3 are operated to descend, and the roller openings 6, 7 are closed by open/close plates 16.

TECHNICAL FIELD

The present invention relates to a chassis dynamometer having rollers on which driving wheels of a test vehicle are rested and rotated to simulate running of the test vehicle on a road in a room, and a method of opening and closing a roller opening of the chassis dynamometer.

BACKGROUND ART

As shown inFIG. 8, there has been proposed a chassis dynamometer including a pit cover104provided with a roller opening103for resting a wheel101of a test vehicle (not shown) on a roller102of a test vehicle (not shown), and an opening open/close plate105that is operated to open and close the roller opening103. Further, reference signs106,107denote a rack and a pinion which cooperate to move the opening open/close plate105. (For instance, see Patent Literatures 1, 2).

Patent Literature 1: Japanese Patent Application Unexamined Publication No. 2010-25654

Patent Literature 2: Japanese Patent Application Unexamined Publication No. 2002-181667

SUMMARY OF THE INVENTION

Technical Problem

In the above-described chassis dynamometer, a height position H1 of an upper end portion102aon an outer peripheral surface of the roller102is set so as to be substantially flush with a height position H2 of an upper surface of the pit cover104. Therefore, there are the following problems.

(1) Upon closing the roller opening103by the opening open/close plate105, a height position H3 of the opening open/close plate105must be higher than the height position of the roller102and the height position of the pit cover104in order to avoid contact between the opening open/close plate105and the upper end portion102aon the outer peripheral surface of the roller102.

(2) When the height position H3 of the opening open/close plate105is higher than the height position of the upper surface of the pit cover104, the opening open/close plate105is projected from the upper surface of the pit cover104. As a result, in a case where a person is worked on the pit cover104in a closed state of the opening open/close plate105, the person may stumble on a portion projecting from the upper surface of the pit cover104. Further, in a case where the test vehicle is moved onto the dynamometer, particularly, when the test vehicle is transported onto the dynamometer by a human power upon a cold start test, etc., the projecting portion will cause large obstruction.

(3) In a case where an RF anechoic chamber is provided on the pit cover104and the test vehicle is subjected to a radio wave irradiation test and measurement of radiation noise within the RF anechoic chamber in a state in which the roller opening103is closed by the opening open/close plate105, if the opening open/close plate105is projected from the upper surface of the pit cover104, there will occur disturbance of the radio wave reflection on the upper surface of the pit cover104and adverse influence will be exerted on accuracy of the measurement or the like.

The present invention has been made in order to provide a chassis dynamometer capable of preventing an opening open/close plate from projecting on a pit cover even when the roller opening is closed by the opening open/close plate, and a method of opening and closing a roller opening of the chassis dynamometer.

Solution to Problem

According to a first aspect of the present invention, there is provided a chassis dynamometer including:

a roller on which a wheel of a test vehicle is rested through a roller opening formed in a pit cover;

a roller opening open/close mechanism that opens and closes the roller opening; and

a roller ascent/descent operation mechanism that operates the roller to ascend and descend,

wherein the roller opening open/close mechanism comprises a roller opening open/close plate that is overlaid on a side of a lower surface of the pit cover and operated to open and close the roller opening, an open/close plate driving section that moves the roller opening open/close date to a roller opening closed position or a roller opening opened position, an open/close plate supporting guide that guides the roller opening open/close plate and supports the roller opening open/close plate in a height position of the pit cover in the roller opening closed position.

According to a second aspect of the present invention, there is provided the chassis dynamometer as described in the first aspect, further including: an engine cooling device including an engine cooling fan disposed in a pit below the pit cover, a ventilation duct that introduces an air flow generated by the engine cooling fan into the test vehicle on the pit cover through a duct opening formed in the pit cover, and a duct ascent/descent mechanism that allows the ventilation duct to expand and retract, and ascend and descend; and a duct opening open/close plate that closes the duct opening in a state in which the ventilation duct is accommodated in the pit using the duct ascent/descent mechanism.

According to a third aspect of the present invention, there is provided the chassis dynamometer as described in the first aspect, wherein the roller ascent/descent operation mechanism comprises a bed on which the roller is mounted, an inclined rail that supports the bed such that the bed is ascendable and descendable, and a bed driving section that allows the bed to run along the inclined rail.

According to a fourth aspect of the present invention, there is provided the chassis dynamometer as described in the third aspect, wherein the bed driving section includes a motor, a feed screw that is rotationally driven by the motor, and a feed nut that converts rotation of the feed screw into slide motion of the bed.

According to a fifth aspect of the present invention, there is provided the chassis dynamometer as described in the fourth aspect, wherein the roller ascent/descent operation mechanism includes a clamp mechanism that fixes the bed on a side of the inclined rail.

According to a sixth aspect of the present invention, there is provided the chassis dynamometer as described in the fifth aspect, wherein the clamp mechanism includes a brake pad disposed on one of the bed and the inclined rail, and a brake plate disposed on the other of the bed and the inclined rail, the brake pad being pressed against the brake plate.

According to a seventh aspect of the present invention, there is provided the chassis dynamometer as described in any one of the first to sixth aspects, wherein the pit cover is provided with an RF anechoic chamber in a test vehicle introducing position in which the roller opening is located.

According to an eighth aspect of the present invention, there is provided a method of opening and closing a roller opening of a chassis dynamometer using a roller on which a wheel of a test vehicle is rested through a roller opening formed in a pit cover, a roller opening open/close mechanism that opens and closes the roller opening by a roller opening open/close plate, and a roller ascent/descent operation mechanism that operates the roller to ascend and descend, the method including:

overlaying the roller opening open/close plate on a side of a lower surface of the pit cover, and sliding the roller opening open/close plate to close the roller opening in a height position of the pit cover by the roller opening open/close plate; and

upon using the roller, sliding the roller opening open/close plate to open the roller opening, and ascending the roller to the height position of the pit cover by the roller ascent/descent operation mechanism.

Advantageous Effects of Invention

In the chassis dynamometer as described in the first aspect, when the roller opening is in the closed state, the roller opening open/close plate is supported to be flush with the upper surface of the pit cover by the open/close plate supporting guide. Therefore, the roller opening open/close plate is prevented from projecting from the upper surface of the pit cover. Accordingly, a person, for instance, a worker can be prevented from stumbling on a portion projecting from the upper surface of the pit cover and falling down. Further, in a case where the test vehicle is moved onto the dynamometer, particularly, when the test vehicle is transported onto the dynamometer by a human power upon a cold start test, etc., it is possible to suppress occurrence of large obstruction which is formed by the projecting portion. Further, in a case where an RF anechoic chamber is provided on the pit cover and the test vehicle is subjected to a radio wave irradiation test and measurement of radiation noise within the RF anechoic chamber in a state in which the roller opening is closed by the opening open/close plate, it is possible to suppress occurrence of disturbance of the radio wave reflection on the upper surface of the pit cover and adverse influence on accuracy of the measurement or the like which are caused when the opening open/close plate is projected from the upper surface of the pit cover.

Further, when the roller opening open/close plate is moved in a direction in which the roller opening is opened, the roller opening open/close plate is released from support by the open/close plate supporting guide and suspended in the pit to thereby open the roller opening. Then, the roller can be operated to ascend to a same height as that of the pit cover by the roller ascent/descent operation mechanism.

In the chassis dynamometer as described in the second aspect, when the wheel of the test vehicle is rested on the roller and the test is carried out, the ventilation duct is allowed to expand and ascend in an upward-downward direction and project onto the pit cover such that an air flow generated by the engine cooling fan is hit on the engine of the test vehicle and the test is carried out while cooling the engine. After completion of cooling, the ventilation duct is allowed to retract and descend in the upward-downward direction. After the ventilation duct is accommodated in the pit, the duct opening can be closed by the duct opening open/close plate.

In the chassis dynamometer as described in the third aspect, the bed on which the roller is mounted is allowed to run along the inclined rail. With this construction, it is possible to appropriately set an inclination angle of the rail. For instance, by setting the inclination angle to a small degree, the heavy bed on which the roller is mounted can be allowed to smoothly ascend and descend by a relatively small force.

In the chassis dynamometer as described in the fourth aspect, the feed screw that constitutes a bed slide driving mechanism is arranged in parallel with the inclined rail, and the feed screw is rotated by the motor. With this construction, it is possible to smoothly slidably move the bed along the rail.

In the chassis dynamometer as described in the fifth aspect, there is provided the clamp mechanism that fixes the bed on the side of the inclined rail. With this construction, it is possible to suppress occurrence of misalignment of the roller which is caused by movement of the bed due to vibration, etc. generated during rotation of the roller.

In the chassis dynamometer as described in the sixth aspect, the clamp mechanism includes the brake pad disposed on one of the bed and the inclined rail, and the brake plate disposed on the other of the bed and the inclined rail, the brake pad being pressed against the brake plate. With this construction, after moving the bed to a predetermined position, the bed can be fixed to the predetermined position by pressing the brake pad onto the brake plate to thereby generate a frictional force therebetween.

In the chassis dynamometer as described in the seventh aspect, in a case where the test vehicle is subjected to a radio wave irradiation test and measurement of radiation noise within the RF anechoic chamber on the pit cover, the roller opening and the duct opening for the engine cooling fan are closed by the roller opening open/close plate, so that the roller can be prevented from giving adverse influence on the radio wave irradiation test and the measurement of radiation noise.

Particularly, by descending the roller by the roller ascent/descent operation device, the roller opening open/close plate can be flush with the upper surface of the pit cover. Therefore, it is possible to suppress disturbance of radio wave reflection which has been conventionally caused due to the open/close plate projecting from the upper surface of the pit cover. As a result, it is possible to subject the test vehicle to the radio wave irradiation test and the measurement of radiation noise within the RF anechoic chamber with high accuracy.

In the method of opening and closing a roller opening of a chassis dynamometer as described in the eighth aspect, in a state in which the roller opening is opened, a position of the roller is ascended to a same height position as that of the pit cover so that the test vehicle can be readily loaded on the roller. Further, after completion of the test, the height position of the roller is descended by the roller ascent/descent operation device, so that the roller opening can be closed in such a manner that the roller is prevented from disturbing the roller opening open/close plate upon closing the roller opening.

DESCRIPTION OF EMBODIMENTS

FIG. 1toFIG. 5show a first embodiment of the present invention.FIG. 1is a side view of a chassis dynamometer1. Disposed within a pit P are a front-wheel roller2on which front wheels of a test vehicle are rested, and a rear-wheel roller3on which rear wheels of the test vehicle are rested. A rotation shaft4of the front-wheel roller2and a rotation shaft4of the rear-wheel roller3are connected to a dynamometer main body (not shown).

An upper end of the front-wheel roller2and an upper end of the rear-wheel roller3are exposed to roller openings (hereinafter referred to simply as openings)6,7formed in a pit cover5. Further, the front wheels and the rear wheels of the test vehicle are respectively rested on the front-wheel roller2and the rear-wheel roller3through the openings6,7.

The front-wheel roller2and the rear-wheel roller3are operated to ascend and descend by a roller ascent/descent operation mechanism8, respectively.

The roller ascent/descent operation mechanism8includes a bed9on which the front-wheel roller2or the rear-wheel roller3is mounted, an inclined rail10on which the bed9is slidably supported, and a bed driving section11that allows the bed9to run along the inclined rail10. The inclined rail10is formed to have a slope with a desired inclination angle θ, for instance 5 degrees. As shown inFIG. 5, the rail10includes a rail main body portion10aand a rail platform10bto which the rail main body portion10ais attached.

The bed driving section11includes a motor (not shown), a feed screw13that is rotationally driven by a gearbox12, and a feed nut14that converts rotational motion of the feed screw13into linear motion of the bed9. The feed screw13is arranged along the inclined rail10.

Next, an opening open/close mechanism15that opens and closes the opening6or7is explained.

As shown inFIG. 2toFIG. 4in enlarged views, the opening open/close mechanism15includes a roller opening open/close plate (hereinafter referred to simply as an open/close plate)16that is operated to open and close the opening6or7, an open/close plate driving section17that moves the roller opening open/close plate16between a roller opening closed position and a roller opening opened position (hereinafter referred to simply as a closed position and an opened position), and an open/close plate supporting guide18that guides the open/close plate16to the closed position and the opened position. In the opened position, the open/close plate supporting guide18is allowed to suspend the open/close plate16in the pit P. In the closed position, the open/close plate supporting guide18supports the open/close plate16in a state in which the open/close plate16is flush with an upper surface of the pit cover5.

The open/close plate16is formed into a foldable belt conveyer shape by connecting both sides of multiple plate members16adisposed parallel to each other through a pair of chain-shaped connecting members. Further, the open/close plate driving section17includes a geared motor, and feeds the open/close plate16having the belt conveyer shape. Although the opening open/close mechanism15on a front-wheel side is explained with reference toFIG. 1toFIG. 4, the opening open/close mechanism on a rear-wheel side has a construction similar to that of the opening open/close mechanism15on the front-wheel side.

As shown inFIG. 1, an RF anechoic chamber19including the openings6,7is formed on the pit cover5. In the RF anechoic chamber19, a radio wave irradiation test and measurement of radiation noise relative to the test vehicle are carried out.

Further, a tire cooling fan20is mounted on the bed9. A ventilating duct20aof the tire cooling fan20has a tip end directed to the opening6,7. When the opening6,7is closed by the open/close plate16, the tip end of the ventilating duct20ais covered together with the roller with the open/close plate16.

The rear-wheel roller3, the roller ascent/descent operation mechanism8, the tire cooling fan20, etc. are mounted on a slide table21that is moveable in a forward-rearward direction of the test vehicle. The slide table21is driven by a slide table driving mechanism22.

The slide table driving mechanism22is includes a motor (not shown), a feed screw24that is rotationally driven by a gearbox23, and a feed nut25that covers rotational motion of the feed screw24into linear motion of the slide table21.

When the motor is rotated in one of clockwise and counterclockwise directions, the rear-wheel roller3is moved in a direction in which a distance from the front-wheel roller2is increased. When the motor is rotated in an inverse direction, the rear-wheel roller3is moved in a direction in which a distance from the front-wheel roller2is decreased. Reference signs26,27denote moveable pit covers that move to follow the movement of the rear-wheel roller3.

FIG. 5shows a clamp mechanism for fixing the bed9to a side of the rail10. In the case where the feed screw13is used in the bed driving section11as described above, there inevitably occurs a slight clearance, i.e., a so-called backlash between the feed screw13and the feed nut14. Therefore, there is a fear that the bed9is moved due to vibration generated during rotation of the rollers2,3, whereby misalignment of the respective rollers2,3is caused.

The clamp mechanism31acts to suppress the misalignment of the roller by fixing the bed9to the side of the rail10. The clamp mechanism31includes a brake pad32and a brake plate33against which the brake pad32is pressed.

The brake pad32is attached to one side portion of the bed9to which the roller3is mounted, through a holder34. The brake plate33is mounted to a side portion of the inclined rail10along the slope of the rail10through a holder35.

Further, after each roller2,3is moved to a predetermined position by means of the feed screw13, the brake pad32is pressed against the brake plate33so that the bed9is fixed to a given position on the side of the rail10. As a result, the rollers2,3can be prevented from being misaligned, respectively.

The brake plate33extends along the rail10and has substantially the same length as that of the rail10. A plurality of brake pads32are disposed along the length direction of the brake plate33and ensure positioning of the beds9and the rollers2,3and fix the beds9and the rollers2,3at desired positions. In the above embodiment, the brake pads32are disposed on the side of the bed9, and the brake plate33is disposed on the side of the rail10. However, contrary to this arrangement, the brake pads32may be disposed on the side of the rail10, and the brake plate33may be disposed on the side of the bed9. Further, in the above embodiment, the brake pads32and the brake plate33are used in the clamp mechanism31. However, the clamp mechanism31is not limited to the above embodiment as long as the bed9is surely fixed to the side of the rail10.

Next, an operation of the chassis dynamometer1according to the first embodiment is explained. In a case where various kinds of running tests of a test vehicle are carried out, the slide table21is slid corresponding to a distance between the front wheels and the rear wheels of the test vehicle such that the rear-wheel roller3is moved to a predetermined position. After that, the front wheels and the rear wheels of the test vehicle are set on the front-wheel roller2and the rear-wheel roller3, respectively.

Then, the bed9is fixed to the side of the rail10by the clamp mechanism31so as to suppress displacement of the bed9, and the roller3is rotated to thereby carry out the various kinds of running tests of the test vehicle.

Upon closing the openings6,7after completion of the running tests, firstly the front-wheel roller2and the rear-wheel roller3are descended by the roller ascent/descent operation mechanism8.

The front-wheel roller2and the rear-wheel roller3are descended to a position in which the front-wheel roller2and rear-wheel roller3are free from interference with the open/close plates16. After that, the open/close plates16are each moved toward the side of the openings6,7by the open/close plate driving section17of the opening open/close mechanism15.

The open/close plates16thus moved are guided by the open/close plate supporting guide18, and at the openings6,7, the open/close plates16become flush with the upper surface of the pit cover5to close the roller openings6,7.

Accordingly, the open/close plates16fed are prevented from projecting from the upper surface of the pit cover5as described in the problem of the conventional art, so that the test vehicle can be smoothly transported onto the pit cover5. In addition, the open/close plates are brought into a state in which the open/close plates are flush with the upper surface of the pit cover. Therefore, in a case where the test vehicle is subjected to a radio wave irradiation test and measurement of radiation noise within the RF anechoic chamber19, it is possible to suppress disturbance of the radio wave reflection which is caused due to projection of the open/close plates16from the upper surface of the pit cover5. As a result, it is possible to perform the radio wave irradiation test and the measurement of radiation noise within the RF anechoic chamber with high accuracy.

FIG. 6andFIG. 7show a second embodiment of the present invention. The second embodiment has the same basic construction as that of the above first embodiment. A main difference between a chassis dynamometer1A according to the second embodiment and the chassis dynamometer1according to the first embodiment resides in that the chassis dynamometer1A according to the second embodiment includes an engine cooling device41for cooling an engine of the test vehicle. Since other parts are same as those of the first embodiment, like reference signs denote like parts, and therefore, detailed explanations therefor are omitted.

The engine cooling device41includes an engine cooling fan42disposed within the pit P, a ventilation duct43introducing an air flow generated by the engine cooling fan42into the test vehicle on the pit cover5through a duct opening5aformed in the pit cover5, and a duct ascent/descent mechanism44that allows the ventilation duct43to ascend or descend.

The duct ascent/descent mechanism44allows the ventilation duct43to ascend and project from the pit cover5through the duct opening5a. The duct ascent/descent mechanism44also allows the ventilation duct43to descend and accommodate the ventilation duct43in the pit P. The duct ascent/descent mechanism44includes an electric jack or the like.

The duct opening5ais opened and closed by a duct opening open/close plate45. Similarly to the open/close plate16for the roller opening, the duct opening open/close plate45is formed into a foldable belt conveyer shape by connecting both sides of multiple plate members disposed parallel to each other through a pair of chain-shaped connecting members.

The duct opening open/close plate45is operated to move between a duct opening closed position and a duct opening opened position by an open/close plate driving section that employs the geared motor46and has the same construction as that of the open/close plate driving section17, and an open/close plate supporting guide having the same construction as that of the open/close plate supporting guide18. In the duct opening opened position as shown inFIG. 6, the duct opening open/close plate45is vertically suspended in the pit P. In the duct opening closed position as shown inFIG. 7, the duct opening open/close plate45is flush with the upper surface of the pit cover5and covers the duct opening5a.

In the chassis dynamometer1A according to the second embodiment, the engine cooling fan42for cooling the engine of the test vehicle is disposed within the pit P and the air flow generated by the engine cooling fan42is hit on the engine of the test vehicle on the pit cover5through the duct43. With this construction, it is not necessary to ensure a space on the pit cover5in which the engine cooling fan42is installed. Further, it is possible to prevent the engine cooling fan42from disturbing the test vehicle upon loading and unloading the test vehicle.

Further, in a case where it becomes unnecessary to cool the test vehicle, the duct43is retracted and accommodated within the pit P, and the duct opening5ais closed by the duct opening open/close plate45so that the duct opening open/close plate45is brought into a state in which the duct opening open/close plate45is flush with the upper surface of the pit cover5. Therefore, it is possible to prevent the duct opening open/close plate45from projecting from the upper surface of the pit cover5and disturbing loading and unloading of the test vehicle.

In addition, also in a case where the test vehicle is subjected to a radio wave irradiation test and measurement of radiation noise within the RF anechoic chamber19formed on the pit cover5, it is possible to suppress disturbance of the radio wave reflection which is caused due to projection of the duct opening open/close plates45from the upper surface of the pit cover5. As a result, it is possible to perform the radio wave irradiation test and the measurement of radiation noise within the RF anechoic chamber19with high accuracy. Furthermore, since the upper surface of the pit cover5can be fully flattened, it is possible to readily carry the test vehicle into the RF anechoic chamber19by a human power upon carrying out a cold start test.

Further, although in the above embodiments, the front-wheel roller2and the rear-wheel roller3are operated to gradually ascend and descend while slantingly running along the inclined rail10, the front-wheel roller2and the rear-wheel roller3may be operated to ascend and descend in a vertical direction. Furthermore, although in the above embodiments, the bed driving section11of the roller ascent/descent operation mechanism8includes the feed screw13and the feed nut14, the bed driving section11may include a hydraulic cylinder, a rack and pinion assembly, a hydraulic jack, etc.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1is a side view showing the whole of a chassis dynamometer according to a first embodiment of the present invention.

FIG. 2is an enlarged side view showing a roller portion in a roller ascended state.

FIG. 3is an enlarged side view showing a roller portion in a roller descended state.

FIG. 4is a side view showing a state in which an open/close plate is closed.

FIG. 5is a schematically explanatory diagram showing a clamp mechanism of a roller.

FIG. 6is a side view showing a chassis dynamometer according to a second embodiment of the present invention.

FIG. 7is a side view of an essential part in a state in which a duct opening open/close plate is closed.

FIG. 8is a sectional view of a conventional art.

REFERENCE SIGNS LIST