CN114166519A

CN114166519A - Chassis dynamometer

Info

Publication number: CN114166519A
Application number: CN202110029919.3A
Authority: CN
Inventors: 一濑明大
Original assignee: Toshiba Mitsubishi Electric Industrial Systems Corp
Current assignee: Toshiba Mitsubishi Electric Industrial Systems Corp
Priority date: 2020-09-10
Filing date: 2021-01-11
Publication date: 2022-03-11
Anticipated expiration: 2041-01-11
Also published as: JP2022046020A; CN114166519B; JP7292810B2

Abstract

The invention provides a chassis dynamometer, which has a pit cover supporting mechanism for a movable pit cover, which realizes the reduction of the weight of the movable pit cover and is compactly configured. The pit cover beam (10) is formed to cover the upper surface and the side surface of the center fixed pit cover (1C). The pit cover beam (10) has pit cover support regions (12A, 12B) on the bottom surface. The pit cover support region (12A) supports a center side end portion roller (5A1) of the movable pit cover (2A), and the pit cover support region (12B) supports a center side end portion roller (5B1) of the movable pit cover (2B). The pit cover support mechanism (90A) is in contact with the pit cover support region (12A) to support the pit cover beam (10). The pit cover support mechanism (90B) is in contact with the pit cover support region (12B) to support the pit cover beam (10).

Description

Chassis dynamometer

Technical Field

The present disclosure relates to a Chassis dynamometer (Chassis dynamo meter) with pit cover (pit cover) support mechanism.

Background

As a test apparatus for a finished vehicle, there is a chassis dynamometer (hereinafter, sometimes referred to as "CHDY") device, and the CHDY (device) is configured to include a roller device movable under a pit in accordance with a wheel base (a distance between a front wheel axle and a rear wheel axle) of a test vehicle. In addition, in the case where a roller device that moves under the pit is provided, a movable pit cover that moves in conjunction with the movement of the roller device is necessary. The movable pit cover constitutes a part of the floor surface.

As conventional techniques related to CHDY having a movable pit cover, there are, for example, a pit cover device disclosed in patent document 1 and a chassis dynamometer disclosed in patent document 2.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2011-

Patent document 2: japanese patent laid-open No. 2001-183259

Disclosure of Invention

Problems to be solved by the invention

The pit cover needs to reduce the deflection of the pit cover generated when the vehicle is carried in and out. Therefore, conventionally, measures such as increasing the strength of the pit cover itself and providing a movable support member dedicated to the pit cover have been required.

The pit cover device disclosed in patent document 1 does not have a dedicated movable support member. Therefore, in the technique disclosed in patent document 1, it is necessary to improve the strength of the pit cover itself.

However, if the strength of the pit cover itself is increased, the weight of the pit cover inevitably increases. Therefore, it is also necessary to increase the output of the driving device for moving the movable pit cover.

As described above, the pit cover device disclosed in patent document 1 has a problem that the weight of the pit cover is increased and the output of the driving device of the movable pit cover is increased.

The chassis dynamometer disclosed in patent document 2 includes a pit cover support mechanism serving as a dedicated movable support member. The pit cover supporting mechanism has the following features (1) and (2).

(1) The pit cover support mechanism is provided in a space below the pit different from the moving roller device.

(2) The rolling member serving as a support member in direct contact with the pit cover is in the shape of a right circular column, and a generatrix of the side surface is a straight line. That is, the upper outer peripheral surface of the surface that becomes the side surface of the rolling member is horizontal.

Since the chassis dynamometer disclosed in patent document 2 has the above feature (1), there is a problem that an increase in the equipment space of the chassis dynamometer is caused.

Since the chassis dynamometer disclosed in patent document 2 has the above feature (2), it is difficult to say that the chassis dynamometer sufficiently follows the contact surface of the pit cover when receiving a load or strain from above.

This is because the upper outer peripheral surface of the rolling member is horizontal and partially contacts the contact surface, and therefore a load biased to one side is applied to the rolling member. As a result, abnormal wear may occur between the rolling member and the pit cover which are in contact with each other.

The above-described problems will be described in detail below. The pit cover on the supported side and the steel frame that becomes the frame for the pit cover are generally made of welded cans. For example, if it is assumed that a steel frame is supported by rolling members, the steel frame itself is strained, bent, or deformed. Further, since strain due to the sheet metal welding is also applied, it is hard to say that the flat surface is stable unlike the machined surface.

When such a surface of the steel frame is supported by a rolling member having an upper outer peripheral surface of a horizontal level, the rolling member locally contacts the steel frame. Thus, a load is locally applied to the rolling member. Therefore, there is a problem that a local portion of the rolling member receiving the load may be damaged, and abnormal wear may be increased.

As described above, the chassis dynamometer disclosed in patent document 2 has the above-described feature (2), and therefore there is a problem that the rolling members and the pit cover having a contact relationship with each other are highly likely to be damaged.

The chassis dynamometer of the present disclosure is made to solve the above-described problems, and an object thereof is to obtain a chassis dynamometer having a pit cover supporting mechanism that exhibits the following effects (1) to (4).

(1) The weight of the movable pit cover is reduced.

(2) The output of a driving device for a movable pit cover is reduced.

(3) A pit cover supporting mechanism for a movable pit cover is compactly formed. A

(4) The supporting member of the pit cover supporting mechanism is not damaged when supporting the movable pit cover.

Means for solving the problems

The disclosed chassis dynamometer is characterized by being provided with: a first roller device having a first roller that can be rotationally driven and that can move in a first direction; a second roller device having a second roller that can be rotationally driven and that can move in the first direction; a pit cover fixed to a central portion of a rectangular shape in plan view, the pit cover being located between the first and second roller devices, the rectangular shape in plan view having the first direction as a long side direction and a second direction orthogonal to the first direction as a short side direction; a pit cover beam provided so as to cover an upper surface and a side surface of the center fixed pit cover; first and second movable pit covers provided along the second direction with the center fixed pit cover interposed therebetween; and first and second pit cover support mechanisms for supporting the pit cover beam from below, wherein the first pit cover support mechanism and the first movable pit cover are movable in the first direction in conjunction with movement of the first roller device, the first pit cover support mechanism is located below the pit cover beam during and before and after movement, the second pit cover support mechanism and the second movable pit cover are movable in the first direction in conjunction with movement of the second roller device, the second pit cover support mechanism is located below the pit cover beam during and before and after movement, and forms a floor surface including the central fixed pit cover and a part of the first and second movable pit covers, and an end of the first movable pit cover on the side of the central fixed pit cover is defined as a first central side end, in the second movable pit cover, an end portion of the center fixed pit cover side is defined as a second center side end portion, the beam for the pit cover has a first central side end supporting region and a second central side end supporting region, the first center-side end supporting region supports the first center-side end, the second center-side end supporting region supports the second center-side end, the first and second pit cover supporting mechanisms each have a supporting member, in the support member, a side structure along the second direction has a barrel shape with a central portion bulging, the support member of the first pit cover support mechanism is in contact with the first center-side end support region to support the pit cover beam, the support member of the second pit cover support mechanism supports the pit cover beam in contact with the second center-side end support region.

Effects of the invention

The chassis dynamometer of the present disclosure includes a dedicated first pit cover supporting mechanism for supporting a first movable pit cover via a pit cover beam, and a dedicated second pit cover supporting mechanism for supporting a second movable pit cover via a pit cover beam.

Therefore, the chassis dynamometer of the present disclosure can reduce the weight of the first and second movable pit covers without increasing the strength of the first and second movable pit covers.

Further, the chassis dynamometer of the present disclosure can reduce the weight of the first and second movable pit covers, and accordingly, can reduce the output of the driving device for moving the first and second movable pit covers together.

The first and second pit cover support mechanisms are located below the pit cover beam during and before and after movement. By setting the installation area of the first and second pit cover supporting mechanisms to the space below the pit cover beam, the space below the floor surface can be effectively utilized.

Further, in the support member, the side structure along the second direction has a barrel shape with a central portion bulging. That is, the outer periphery of the cross section of the upper portion of the side structure is arched.

Therefore, by increasing the degree of freedom of the contact surfaces between the first and second center-side end support regions and the support member, local deformation and strain of the first and second center-side end support regions can be absorbed by the contact surfaces of the support member.

As a result, the first and second pit cover supporting mechanisms in the chassis dynamometer of the present disclosure can support the first and second movable pit covers via the pit cover beam without damaging the contact area between the supporting member and the pit cover beam.

Drawings

Fig. 1 is a perspective view showing a configuration of a chassis dynamometer according to an embodiment.

Fig. 2 is an explanatory diagram schematically showing a side cross-sectional structure of the chassis dynamometer according to the embodiment.

Fig. 3 is an explanatory view schematically showing a cross-sectional structure a-a of fig. 2.

Fig. 4 is a sectional view schematically showing a cross-sectional structure of the pit cover according to the embodiment.

Fig. 5 is a perspective view showing the entire configuration of the pit cover supporting mechanism.

Fig. 6 is an explanatory diagram (1) showing a cross-sectional structure of the pit cover supporting mechanism.

Fig. 7 is an explanatory diagram (2) showing a cross-sectional structure of the pit cover supporting mechanism.

Fig. 8 is an explanatory diagram schematically showing a side cross-sectional structure of a chassis dynamometer which is a basic technique.

Fig. 9 is a cross-sectional view schematically showing the structure of the C-C section of fig. 8.

Fig. 10 is a cross-sectional view schematically showing a cross-sectional structure of a pit cover according to the basic technique.

Description of the reference numerals

1 fixed pit cover

1C central fixed pit cover

2. 2A, 2B movable pit cover

5A, 5B movable pit cover roller

7 CHDY (Chassis dynamometer)

8 floor surface

10 pit cover beam

12A, 12B pit cover support area

21. Equipment under 22 pits

Equipment frame under 26 pits

Vehicle for 50 tests

51 front wheel

52 rear wheel

41. 41A, 41B, 42A, 42B roller

61. 61A, 61B, 62A, 62B roller device

90. 90A, 90B pit cover supporting mechanism

91 receiving roller

92 roller support bracket

93 reaction force adjusting spring

94 connecting pin

98 stop bolt

Detailed Description

< basic technique >

Fig. 8 is an explanatory diagram schematically showing a side sectional structure of a general chassis dynamometer (CHDY70) which becomes a basic technique of the present disclosure. Fig. 9 is an explanatory diagram schematically showing a cross-sectional structure of C-C of fig. 8. Fig. 10 is a cross-sectional view schematically showing a cross-sectional structure of a pit cover according to the basic technique, and corresponds to a D-D cross-section of fig. 8. Fig. 8 to 10 each show an XYZ rectangular coordinate system.

The basic technology of CHDY70 is provided in facility space SP30, facility space SP30 is provided in facility base section 30 under floor surface 8, and CHDY70 enables test by placing test vehicle 50 on floor surface 8. CHDY70 includes as main components an under pit device 121 corresponding to front wheel 51 and an under pit device 122 corresponding to rear wheel 52 of test vehicle 50.

The pit lower equipment 121 has a roller device 161 fixed to a support table 123. The roller device 161 includes a rotation driving unit 131, and is capable of rotationally driving the roller 141 in the roller rotation direction D4 by the rotation driving unit 131. Two roller devices 161 are provided corresponding to the pair of front wheels 51. The pair of front wheels 51 of the test vehicle 50 are disposed on the pair of rollers 141 during the test.

The pit equipment 122 is provided with a moving guide 125 on a support table 124. A roller device mounting member 134 is mounted on the moving guide 125 via a linear guide 129. The linear guide 129 functions as a linear motion bearing that can move along the movement guide 125. Thus, the roller device mounting member 134 can move in the apparatus moving direction D1.

The roller device 162 is mounted to the roller device mounting member 134. Thus, CHDY70 is configured such that roller device 162 moves in the device moving direction D1. The roller device 162 includes a rotation driving unit 132, and the roller 142 can be rotationally driven in the roller rotation direction D4 by the rotation driving unit 132.

As shown in fig. 9, two roller devices 162(162A and 162B) are provided corresponding to the pair of rear wheels 52, and the pair of rear wheels 52 of the test vehicle 50 are disposed on the pair of rollers 142(142A and 142B) at the time of the test.

The CHDY70 is configured such that the

roller devices

162A and 162B mounted together to the roller device mounting member 134 integrally move in the machine moving direction D1.

The movable pit cover 102 is provided so as to be connected to the roller device 162 at the front side (-Y direction) and at the rear side (+ Y direction). The movable pit cover 102 is coupled to the roller device 162 and moves in conjunction with the movement of the roller device 162 in the device moving direction D1.

Therefore, the CHDY70 moves the pair of rollers 142 according to the length of the wheelbase of the test vehicle 50, and the movable pit cover 102 located forward and rearward of the pair of rollers 142 after the movement forms the floor surface 8.

In addition, a fixed pit cover 101 is provided at a region that becomes the floor surface 8. Therefore, the floor surface 8 is configured by an upper portion of the equipment base 30, an exposed portion of the pair of rollers 141, an exposed portion of the pair of rollers 142, the fixed pit cover 101, and a part (surface exposed portion) of the movable pit cover 102.

The movable pit cover 102 is configured such that a plurality of crawler belt units 135 are coupled to each other by a link chain 136, and as shown in fig. 10, movable pit cover rollers 105 are provided at both ends in the X direction. In fig. 10, the movable pit cover 102 has a double-layer structure.

A pair of fixed pit covers 101 are provided on the outer sides in the X direction (the (-X direction side, + X direction side) with respect to the movable pit cover 102, and the pair of fixed pit covers 101 are connected to a steel frame 108 on the movable pit cover 102 side, respectively.

The movable pit cover rollers 105 at both ends are disposed on the bottom surfaces of the corresponding steel frames 108. Therefore, the movable pit cover 102 can be moved in the Y direction by rotating the movable pit cover rollers 105 at both ends on the bottom surface of the steel frame 108.

Like the pit cover supporting mechanism disclosed in patent document 1, the basic technology CHDY70 does not include a dedicated pit cover supporting mechanism for supporting the movable pit cover 102.

Therefore, in the CHDY70, as in the pit cover device disclosed in patent document 1, the problem of the movable pit cover 102 becoming heavier and the problem of the increase in output of the drive device (drive device of the roller device 162) of the movable pit cover 102 are not solved.

Further, when the movable pit cover 102 is enlarged, the rectangular portion of the YZ plane, which is the basic configuration of the crawler belt unit, is also enlarged in shape. When the rectangular portion has a large shape, the corner of the rectangular portion protrudes above the floor surface 8 in the process of moving the crawler belt unit downward to the floor surface 8 or in the process of moving the crawler belt unit upward to the floor surface 8. Here, the protruding region is referred to as a "step when moving" of the movable pit cover 102.

Further, if the movable pit cover 102 is increased, the gap between the connected crawler belt units is also of an unnoticeable size. Here, the gap is referred to as an "inter-track gap" of the movable pit cover 102.

When the movable pit cover 102 is enlarged in this manner, a step or a gap between the crawler belts occurs during movement, and therefore, foreign matter falls under the floor surface 8 or comes into contact with a finger of an operator during a test. As a result, the preparation of the test vehicle 50 by the operator is adversely affected.

Further, since the movable pit cover 102 is configured to correspond to the pair of rollers 142, the shape of the movable pit cover 102 alone becomes large and the weight thereof also becomes heavy.

Therefore, the capacity of the moving motor (in the basic technique, the moving motor of the roller device 162) for moving the movable pit cover 102 also needs to be increased, and there is a problem that the space for installing the moving motor also needs to be enlarged.

The CHDY7 of the embodiments described below achieves elimination of the above-described problems.

< embodiment >

(integral constitution)

Fig. 1 is a perspective view showing a configuration of a chassis dynamometer (CHDY7) according to an embodiment of the present disclosure. Fig. 2 is an explanatory diagram schematically showing a side cross-sectional structure of CHDY7 according to the present embodiment. Fig. 3 is an explanatory view schematically showing a cross-sectional structure a-a of fig. 2. Fig. 4 is a sectional view schematically showing a cross-sectional structure of the pit cover, and corresponds to a section B-B in fig. 2. Fig. 1 to 4 each show an XYZ rectangular coordinate system.

As shown in fig. 1 and 2, CHDY7 is provided in facility space SP30, facility space SP30 is provided in facility foundation section 30 under floor surface 8, and facility space SP30 enables test by placing test vehicle 50 on floor surface 8. CHDY7 includes as main components an under pit device 21 corresponding to front wheels 51 of test vehicle 50 and an under pit device 22 corresponding to rear wheels 52.

As shown in fig. 1, in the floor surface 8, a fixed pit cover 1 or a movable pit cover 2 is provided outside the surface exposed areas of a pair of rollers 41 (

rollers

41A and 41B) and a pair of rollers 42 (

rollers

42A and 42B).

As shown in fig. 2, the under pit equipment 21 has a roller device 61 fixed to the support table 23. The roller device 61 includes the rotation driving unit 31, and the roller 41 can be rotationally driven in the roller rotation direction D4 by the rotation driving unit 31. The roller device 61 is constituted by two

roller devices

61A and 61B corresponding to the pair of front wheels 51. That is, the roller device 61A is for the roller 41A, and the roller device 61B is for the roller 41B. The pair of front wheels 51 of the test vehicle 50 are disposed on the pair of rollers 41 during the test.

The pit equipment 22 is provided with a moving guide rail 25 on a fixed support 24. A roller device mounting member 34 is mounted on the moving guide 25 via a linear guide 29. The linear guide 29 functions as a linear motion bearing that can move along the movement guide 25. Thus, the roller device mounting member 34 is movable in the apparatus moving direction D1.

As shown in fig. 3, the

roller devices

62A and 62B are mounted together to the roller device mounting member 34. Thus, the CHDY7 of the present embodiment is configured such that the

roller devices

62A and 62B move integrally along the machine moving direction D1.

The

roller devices

62A and 62B each have a rotation driving portion 32. The roller device 62A as the first roller device can rotationally drive the roller 42A as the first roller in the roller rotation direction D4 by the rotational drive section 32. The roller device 62B as the second roller device can rotationally drive the roller 42B as the second roller in the roller rotation direction D4 by the rotational drive unit 32. Thus, the under pit apparatus 122 has two

roller devices

62A and 62B corresponding to the pair of rear wheels 52.

That is, the roller device 62A as the first roller device is for the roller 42A, and the roller device 62B as the second roller device is for the roller 42B. The pair of rear wheels 52 of the test vehicle 50 are disposed on the pair of

rollers

42A and 42B during the test.

The movable pit cover 2 is a combination of movable pit covers 2A and 2B. The movable pit cover 2A as the first movable pit cover has a front (-Y direction) portion and a rear (+ Y direction) portion with respect to the roller 42A on the left side (-X direction side).

The front and rear portions of the movable pit cover 2A are connected to each other via a roller peripheral pit cover 28 (28A). The roller periphery pit cover 28A is integrally configured with the roller device 62A, and is provided with an opening portion for exposing a part of the roller 42A.

The movable pit cover 2B as the second movable pit cover has a front portion and a rear portion with respect to the roller 42B on the right side (+ X direction side).

The front and rear portions of the movable pit cover 2B are connected via a roller peripheral pit cover 28 (28B). The roller periphery pit cover 28B is configured integrally with the roller device 62B, and is provided with an opening portion for exposing a part of the roller 42B.

Therefore, the movable pit cover 2A moves in conjunction with the movement of the roller device 62A in the device moving direction D1, and the movable pit cover 2B moves in conjunction with the movement of the roller device 62B in the device moving direction D1.

In the CHDY7 of the embodiment, the movable pit covers 102 of 1 unit are dispersed into the movable pit covers 2A and 2B of 2 units, compared to the basic technology of CHDY70, and thus the movable pit covers of 1 unit can be reduced. Therefore, the load generated by the movable pit cover can be dispersed to the movable pit cover 2A and the movable pit cover 2B.

As described above, by moving the

roller devices

62A and 62B, the CHDY7 can change the arrangement of the pair of

rollers

42A and 42B according to the length of the wheelbase of the test vehicle 50. Movable pit covers 2A and 2B are provided in the front and rear areas of the pair of

roller devices

62A and 62B after the movement. Therefore, even after the arrangement of the

rollers

42A and 42B is changed, the floor surface 8 can be configured by a part of the movable pit covers 2A and 2B.

As shown in fig. 1, the fixed pit cover 1 is provided in both end regions in the X direction, in front of the pair of rollers 41 (in the (-Y direction), in a part between the pair of rollers 41 and the pair of rollers 42, between the

rollers

41A and 41B, between the

rollers

42A and 42B, and between the movable pit covers 2A and 2B exposed on the surface. The fixed pit cover 1 described above always constitutes the floor surface 8 of the pit.

Hereinafter, among the above-described various fixed pit covers 1, the fixed pit cover 1 provided between the

rollers

42A and 42B and between the movable pit covers 2A and 2B exposed on the surface may be referred to as a "central fixed pit cover 1C". As shown in fig. 1, the center-fixed pit cover 1C is covered with a pit cover beam 10 described later.

The center-fixed pit cover 1C is positioned between the

rollers

42A and 42B in the X direction, and has a rectangular shape in plan view with the Y direction as the long side direction and the X direction orthogonal to the Y direction as the short side direction.

Further, the Y-direction forming region of the center-fixed pit cover 1C (pit cover beam 10) includes the Y-direction moving range of the

roller devices

62A and 62B. The center-fixed pit cover 1C is supported by a dedicated support column not shown.

As shown in fig. 1 and 2, the floor surface 8 is composed of an upper portion of the facility base 30, exposed portions of the pair of rollers 41, exposed portions of the pair of rollers 42, the fixed pit cover 1, and a part (surface exposed portion) of the movable pit cover 2.

As a constituent material of the fixed pit cover 1 and the movable pit cover 2(2A and 2B), a general steel material can be considered.

The movable pit covers 2A and 2B are each configured such that a plurality of crawler belt units 35 are coupled to each other by a link chain 36. In fig. 4, the movable pit covers 2A and 2B have a two-layer structure.

As shown in fig. 4, movable pit cover rollers 5A are provided at both ends of the movable pit cover 2A in the X direction. The movable pit cover roller 5A on the right side (+ X direction side) is a center side end portion roller 5A1 (first center side end portion), and the movable pit cover roller 5A on the left side (-X direction side) is an outer side end portion roller 5A2 (first outer side end portion).

Similarly, movable pit cover rollers 5B are provided at both ends of the movable pit cover 2B in the X direction. The left movable pit cover roller 5B serves as a center side end portion roller 5B1 (second center side end portion), and the right movable pit cover roller 5B serves as an outer side end portion roller 5B2 (first outer side end portion).

As shown in fig. 3 and 4, the pit cover beam 10 is formed to cover the upper surface and the side surface of the center fixed pit cover 1C.

As shown in fig. 4, the pit cover beam 10 has a pit cover support region 12A on the bottom surface on the-X direction side, which supports the center side end portion roller 5a1 as the first center side end portion. The pit cover support region 12A serves as a first center side end support region.

Similarly, the pit cover beam 10 has a pit cover support region 12B on the bottom surface on the + X direction side for supporting the center side end portion roller 5B1 as the second center side end portion. The pit cover support region 12B serves as a second center side end support region.

As shown in fig. 4, a fixed pit cover 1 is present on the outer side (the (-X direction side) of a movable pit cover 2A, a steel frame 6A is connected to an end of the fixed pit cover 1, and an outer side end roller 5a2 is supported by a pit cover support region 16A constituting the bottom surface of the steel frame 6A.

Similarly, a fixed pit cover 1 is present on the outer side (+ X direction side) of the movable pit cover 2B, a steel frame 6B is connected to an end of the fixed pit cover 1, and the outer side end roller 5B2 is supported by a pit cover support region 16B constituting the bottom surface of the steel frame 6B.

Therefore, the movable pit cover 2A can be moved in the Y direction by rotating the center side end roller 5a1 and the outer side end roller 5a2 at both ends in the pit

cover support regions

12A and 16A.

Similarly, the movable pit cover 2B can be moved in the Y direction by rotating the center side end roller 5B1 and the outer side end roller 5B2 at both ends in the pit

cover support regions

12B and 16B.

As described above, the pit cover supporting area 12A of the pit cover beam 10 is an area for supporting the center side end portion roller 5a1 of the movable pit cover 2A, and the pit cover supporting area 12B of the pit cover beam 10 is an area for supporting the center side end portion roller 5B1 of the movable pit cover 2B.

Further, the under pit facility 22 of CHDY7 of the present embodiment is configured such that the floor surface 8 is constituted by the movable pit covers 2(2A and 2B) and the center fixed pit cover 1C, except for a part (surface exposed region) of the pair of rollers 42(42A and 42B).

The CHDY7 of the present embodiment includes two pit cover supporting mechanisms 90A as first pit cover supporting mechanisms on the upper portion of the roller device 62A as the first roller device, and includes two pit cover supporting mechanisms 90B as second pit cover supporting mechanisms on the upper portion of the roller device 62B as the second roller device. That is, the CHDY7 of the embodiment has a total of four pit cover supporting mechanisms 90(90A and 90B).

One of the two pit cover supporting mechanisms 90A is disposed in front of the roller 42A (-Y direction), and the other is disposed behind the roller 42A (+ Y direction). Similarly, one of the two pit cover supporting mechanisms 90B is disposed in front of the roller 42B, and the other is disposed behind (in the + Y direction) the roller 42B.

The two pit cover support mechanisms 90A are located at the same position in the left-right direction (X direction), and the two pit cover support mechanisms 90B are located at the same position in the left-right direction. Further, there is no difference between the two pit cover supporting mechanisms 90A other than the arrangement position, and there is no difference between the two pit cover supporting mechanisms 90B other than the arrangement position.

For convenience of explanation, one pit cover supporting mechanism 90A of the two pit cover supporting mechanisms 90A will be described below as a representative, and one pit cover supporting mechanism 90B of the two pit cover supporting mechanisms 90B will be described below as a representative.

The pit cover supporting mechanism 90A as the first pit cover supporting mechanism is provided above the roller device 62A as the first roller device, and supports the pit cover beam 10 from below. The pit cover supporting mechanism 90B as a second pit cover supporting mechanism is provided above the roller device 62B as a second roller device, and supports the pit cover beam 10 from below.

Pit

cover support mechanisms

90A and 90B are provided on the pit equipment frame 26 common to the

roller devices

62A and 62B.

Therefore, the pit

cover support mechanisms

90A and 90B can move in the Y direction (first direction) in accordance with the movement of the

roller devices

62A and 62B.

The pit cover support mechanism 90A is located below (on the (-X direction side) the pit cover beam 10 during movement and before and after movement, and the pit cover support mechanism 90B is located below (on the (+ X direction side) the pit cover beam 10 during movement and before and after movement.

The pit

cover support mechanisms

90A and 90B each have a receiving roller 91 serving as a support member at the uppermost portion. As a material constituting the receiving roller 91, for example, a steel material subjected to heat treatment is considered. The structure of the receiving roller 91 will be described in detail later.

As shown in fig. 3 and 4, (the receiving roller 91 of) the pit cover supporting mechanism 90A supports the pit cover beam 10 in contact with the pit cover supporting region 12A as the first center side end portion supporting region.

The pit cover support mechanism 90B (the receiving roller 91 thereof) supports the pit cover beam 10 in contact with the pit cover support region 12B as the second center side end portion support region.

Therefore, the pit cover supporting mechanism 90A can support the movable pit cover 2A via the pit cover beam 10, and the pit cover supporting mechanism 90B can support the movable pit cover 2B via the pit cover beam 10.

(pit cover supporting mechanism)

Fig. 5 is a perspective view showing the entire configuration of the pit cover supporting mechanism. Fig. 6 and 7 are explanatory views each showing a cross-sectional structure of the pit cover supporting mechanism. Fig. 5 to 7 each show an XYZ rectangular coordinate system. In addition, fig. 6 shows a sectional structure on the XZ plane of fig. 5, and fig. 7 shows a sectional structure on the YZ plane of fig. 5.

Since the pit

cover supporting mechanisms

90A and 90B have the same configuration, the "pit cover supporting mechanism 90" will be described below as a general term for the "pit

cover supporting mechanisms

90A and 90B".

As shown in these figures, the pit cover supporting mechanism 90 includes the under-pit equipment frame 26, four reaction force adjusting springs 93, a roller supporting bracket 92, four reaction force setting bolts 96, four fixing nuts 97, the receiving roller 91, a pair of receiving roller members 81, and a coupling pin 94 as main components.

The pit equipment frame 26 serves as a base of the pit cover support mechanism 90. As shown in fig. 3, the under pit equipment frame 26 is provided between the

rollers

42A and 42B above the roller device 62.

A roller support bracket 92 serving as a support bracket for the receiving roller 91 is provided above the under pit equipment frame 26. The under pit equipment frame 26 and the roller support bracket 92 are coupled via four reaction force adjusting springs 93. Four reaction force setting bolts 96 are provided corresponding to the four reaction force adjusting springs 93.

The four reaction force adjustment springs 93 are attached along the outer peripheries of the shaft portions of the corresponding reaction force setting bolts 96 between (the upper surface of) the under pit apparatus frame 26 and (the lower surface of) the roller support bracket 92.

The four reaction force setting bolts 96 are provided so that the heads thereof are embedded in the under-pit equipment frame 26, and the tip end portions of the shaft portions are fixed to the upper surface of the roller support bracket 92 by fixing nuts 97.

Inside the roller support bracket 92, shaft portions of the four reaction force setting bolts 96 are provided so as to have gaps 85 along the outer periphery. Inside the under-pit equipment frame 26, shaft portions of the four reaction force setting bolts 96 are provided with gaps 86 along the outer periphery. In the under-pit equipment frame 26, a relief space 87 is provided below the heads of the four reaction force setting bolts 96.

Therefore, the pit cover supporting mechanism 90 can adjust the reaction force against the load applied to the receiving roller 91 by the elastic force of the four reaction force adjusting springs 93. Each of the reaction force adjusting springs 93 has an elastic force in the spring expansion and contraction direction D8, which is the height direction.

Further, a stopper bolt 98 is attached to a central portion of the upper surface of the under pit equipment frame 26. The stopper bolt 98 is fixed to the under-pit equipment frame 26 by a fixing nut 99 so that the apex of the head portion is at a predetermined height from the upper surface of the under-pit equipment frame 26. That is, the lower limit when the roller support bracket 92 is lowered is limited to the interval Δ H by the head of the stopper bolt 98.

Thus, the stopper bolt 98 functions as a height regulating member that regulates the height of the lower surface of the roller support bracket 92 from the upper surface of the under-pit equipment frame 26 as the base to be not lower than a predetermined height.

A specific example of the spring force of the four reaction force adjusting springs 93 in consideration of the presence of the stopper bolt 98 is shown below.

Here, the pit cover deflection amount sp (kgf) which is the deflection load amount corresponding to the total weight of the movable pit covers 2A and 2B, and the vehicle deflection amount sm (kgf) which is the deflection load amount corresponding to the weight of the test vehicle 50 are considered. In this case, the total deflection (load) amount ST is the sum of the pit cover deflection amount SP and the vehicle deflection amount SM (ST ═ SP + SM).

Further, considering the deformation, deflection, and the like of the movable pit covers 2A and 2B, it is estimated that the pit cover deflection amount SP is about 1/10 load amount of the total weight of the movable pit covers 2A and 2B.

In addition, the vehicle deflection amount SM is estimated to be about 1/2 load amount of the weight of the test vehicle 50 in consideration of deformation, deflection, and the like of the test vehicle 50.

As described above, the distance between the lower surface of the roller support bracket 92 and the head upper surface of the stopper bolt 98 is set to the distance Δ H by the stopper bolt 98. In this case, it is preferable to use a spring having a spring constant SR satisfying the following expression (1) as the reaction force adjusting spring 93.

SR＝ST/ΔH…(1)

Further, since the pit cover deflection SP is considered to be substantially constant, the vehicle deflection SM can be roughly classified into 3 types based on the test equipment specifications as follows.

700 to 1000 (kgf): vehicle deflection SM for light-duty vehicle

1000 to 2500 (kgf): vehicle deflection SM of common vehicle and truck class

2500(kgf) or more: small truck to large truck grade vehicle deflection SM

Therefore, it is preferable that the pit cover supporting mechanism 90 be configured by dividing the spring constant SR of the reaction force adjusting spring 93 into 3 types according to the 3 types of vehicle deflection amount SM.

Further, since the pit cover supporting mechanism 90 of the present embodiment uses the four reaction force adjusting springs 93 connected in parallel between the roller supporting bracket 92 and the under-pit apparatus frame 26, the spring constant SR0 required for each of the four reaction force adjusting springs 93 is expressed by the following equation (2).

SR0＝1/4{ST/ΔH}…(2)

In this way, the pit cover supporting mechanism 90 of CHDY7 adjusts the reaction force against the load applied to the adjustment receiving roller 91 by setting the spring constant SR0 of each of the four reaction force adjustment springs 93.

A pair of receiving roller members 81 are provided on the upper surface of the roller support bracket 92, and a receiving roller 91 is provided between the pair of receiving roller members 81. Further, a connecting pin 94 having a shaft portion penetrating the center of the receiving roller 91 is provided between the receiving

roller members

81, 81. Since a cylindrical roller bearing, not shown, is provided at the center of the receiving roller 91, the receiving roller 91 can rotate in the receiving roller rotating direction D9 with the connecting pin 94 as a rotation axis. Further, in the connecting pin 94 serving as a predetermined rotation shaft, a shaft stopper 95 is provided at a distal end portion exposed through the receiving roller 91.

Fig. 6 (b) shows an enlarged view of the shape of the upper outer peripheral surface S91 of the receiving roller 91 on the XZ plane, shown in fig. 6 (a). In the receiving roller 91, the side structure on the XZ plane has an upper outer peripheral surface S91. As shown in fig. 6 (b), the upper outer peripheral surface S91 has an arch shape with a central portion bulging.

The three-dimensional shape that rotates about the rotation axis J94 (the center axis of the coupling pin 94) with the upper outer peripheral surface S91 as a generatrix L91 is the outer peripheral shape of the receiving roller 91. That is, in the receiving roller 91 of the pit cover supporting mechanism 90, the side surface structure along the X direction is a special cylindrical structure having a barrel shape with a raised central portion.

In this way, each of the pit

cover support mechanisms

90A and 90B has a receiving roller 91 as a support member, and the receiving roller 91 has a barrel shape in which a side surface structure along the X direction as the second direction is bulged at a central portion.

The receiving roller 91 of the pit cover supporting mechanism 90A contacts the pit cover supporting region 12A to support the pit cover beam 10, and the receiving roller 91 of the pit cover supporting mechanism 90B contacts the pit cover supporting region 12B to support the pit cover beam 10.

(effects, etc.)

The above-described CHDY7 according to the present embodiment can move the roller device 62 in the Y direction by a drive motor, not shown, in accordance with the wheelbase of the test vehicle 50.

At this time, the movable pit covers 2A and 2B, and the two pit

cover supporting mechanisms

90A and 90B also move in conjunction with the movement of the roller device 62 in the Y direction.

The arrangement coordinates of the two pit cover supporting mechanisms 90A in the X direction do not change before and after the movement of the roller device 62A.

Further, as described above, since the Y-direction forming region of the pit cover beam 10 includes the Y-direction movement range of the roller device 62A, the arrangement coordinates in the Y-direction of the two pit cover support mechanisms 90A become the arrangement coordinates of the pit cover beam 10 during and before and after the movement of the roller device 62.

The two pit cover supporting mechanisms 90B do not change the arrangement coordinates in the X direction and the arrangement coordinates in the Y direction become the arrangement coordinates of the pit cover beam 10 during and before and after the movement of the roller device 62B, as in the pit cover supporting mechanism 90A.

In this way, the two pit cover supporting mechanisms 90A as the first pit cover supporting mechanisms are located below (on the (-X direction side) of the pit cover beam 10 during movement and before and after movement, and the two pit cover supporting mechanisms 90B as the second pit cover supporting mechanisms are located below (on the (+ X direction side) of the pit cover beam 10 during movement and before and after movement.

Therefore, the receiving rollers 91 of the pit

cover supporting mechanisms

90A and 90B maintain the contact relationship with the pit

cover supporting areas

12A and 12B of the pit cover beam 10 during and before and after the movement of the

roller devices

62A and 62B.

That is, even if the arrangement of the roller device 62A (the roller 42A) is changed, the two pit cover supporting mechanisms 90A can support the pit cover beam 10 by the receiving rollers 91 coming into contact with the pit cover supporting area 12A, respectively.

Similarly, even if the arrangement of the roller device 62B is changed, the two pit cover supporting mechanisms 90B can support the pit cover beam 10 by the receiving rollers 91 coming into contact with the pit cover supporting area 12B.

As described above, the pit cover beam 10 supports the center side end portion roller 5a1 of the movable pit cover 2A through the pit cover support region 12A, and supports the center side end portion roller 5B1 of the movable pit cover 2B through the pit cover support region 12B.

Therefore, the two pit cover support mechanisms 90A can support the movable pit cover 2A from below via the pit cover beam 10. Similarly, the two movable pit covers 2B can support the movable pit covers 2B from below via the pit cover beam 10.

The CHDY7 of the present embodiment includes two pit

cover support mechanisms

90A and 90B dedicated to support the movable pit covers 2A and 2B via the pit cover beam 10.

The movable pit covers 2A and 2B correspond to the first and second movable pit covers, and the pit

cover support mechanisms

90A and 90B correspond to the first and second pit cover support mechanisms.

Therefore, since the CHDY7 of the present embodiment includes the dedicated pit cover supporting mechanism 90, it is not necessary to increase the strength of the movable pit covers 2A and 2B, and the movable pit covers 2A and 2B can be reduced in weight.

Further, the CHDY7 of the present embodiment can reduce the weight of the movable pit covers 2A and 2B, and accordingly, can reduce the output of the moving motors for moving the movable pit covers 2A and 2B together.

Furthermore, since the CHDY7 distributes the movable pit covers 2 into the movable pit covers 2A and 2B of 2 units, the load generated by the movable pit covers 2 can be distributed to the movable pit covers 2A and 2B, and accordingly, the deflection generated in the movable pit covers 2A and 2B can be reduced.

This point will be described in detail below. A general flexural type of the beam is represented by the following formula (3). The beam in the formula (3) corresponds to the movable pit covers 2A and 2B, respectively.

δ＝W·L³/(K·E·I)…(3)

In formula (3), δ: deflection amount of beam, W: load from above, L: distance between fulcrums of the beam, K: coefficient based on support system, E: young's modulus of beam, I: the beam moment of inertia and the deflection δ are deformation amounts when a load is applied.

In the CHDY7 of the present embodiment, the movable pit cover 2 is divided into the movable pit covers 2A and 2B, and the inter-fulcrum distance L (proportional to the width of the movable pit cover in the X direction) can be reduced to about 1/2 by that much as compared with the configuration of the basic technology, CHDY 70.

Therefore, when the parameters other than the inter-fulcrum distance L in equation (3) are the same, the amount δ of deflection of each of the movable pit covers 2A and 2B can be set to about 1/8 as compared with the movable pit cover 102 of CHDY 70.

In the CHDY7 of the present embodiment, the movable pit cover 2 is divided into the movable pit covers 2A and 2B, and the area moment of inertia I (which is proportional to the load (mainly the load generated by the test vehicle 50) applied to 1 unit of the movable pit cover) can be reduced to about 1/2 as compared with the case of CHDY 70.

Therefore, when parameters other than the second moment of area I in equation (3) are the same, the amount δ of deflection of each of the movable pit covers 2A and 2B can be set to about 1/2 as compared with the movable pit cover 102 of CHDY 70.

The pit

cover support mechanisms

90A and 90B are located below the pit cover beam 10 during and before and after movement. By setting the installation region of the pit

cover support mechanisms

90A and 90B to the space below the pit cover beam 10, the space below the floor surface 8 can be effectively utilized.

That is, a combination structure of two pit cover supporting mechanisms 90A and two pit cover supporting mechanisms 90B can be provided relatively compactly under the floor surface 8.

In the receiving roller 91 of the support member, the side structure along the X direction (second direction) is formed in a barrel shape with a central portion bulging. That is, the upper outer peripheral surface S91 of the upper portion of the receiving roller 91 is arcuate when viewed in the side direction.

Therefore, the contact surface between the pit

cover support regions

12A and 12B, which are the first and second center side end portion support regions, and the receiving roller 91 has a high degree of freedom, and therefore local strain, damage, or deformation of the pit

cover support regions

12A and 12B can be absorbed by the contact surface of the receiving roller 91.

Therefore, in the CHDY7 of the present embodiment, even if a load from the upper direction such as a local eccentric load or one contact (Japanese: Takara たり) is applied, abnormal wear does not occur between the receiving roller 91 and the pit cover beam 10.

As a result, the pit cover supporting mechanism 90 in the CHDY7 of the present embodiment can support the movable pit covers 2A and 2B via the pit cover beam 10 without damaging the contact area between the pit cover supporting mechanism 90 and the pit cover beam 10.

The pit cover supporting mechanism 90 includes four reaction force adjusting springs 93, and the four reaction force adjusting springs 93 are provided between the under-pit equipment frame 26 serving as a base and the roller supporting bracket 92, and each have an elastic force in a spring extending and contracting direction D8 which is a height direction (Z direction).

Further, the roller support bracket 92 as a support bracket for the receiving roller 91 is vertically movable in the receiving roller rotating direction D9 by the elastic force of the four reaction force adjusting springs 93. That is, the receiving roller 91 can move up and down following the roller support bracket 92.

Therefore, by the vertical movement of the receiving roller 91, the displacement of the outer peripheral surface of the receiving roller 91 (the contact surface with the pit cover beam 10) and the displacement due to the instantaneous load can be effectively absorbed.

As described above, the pit cover supporting mechanism 90 in the CHDY7 according to the present disclosure can appropriately set the spring constants SR0 of the four reaction force adjusting springs 93 and adjust the reaction force against the load applied to the roller 91. Therefore, the CHDY7 can stably support the flexural load amount generated by the test vehicle 50 and the movable pit covers 2A and 2B when the test vehicle 50 is carried in and out by the pit cover support mechanism 90.

The pit cover support mechanism 90 has a stopper bolt 98 provided on the surface of the under-pit equipment frame 26 as a base.

The stopper bolt 98 functions as a height regulating member that regulates the height of the lower surface of the roller support bracket 92 from the upper surface of the under-pit equipment frame 26 to be not lower than a predetermined height. That is, the maximum lowering distance in the case where the receiving roller 91 is lowered is limited to the interval Δ H by the stopper function of the stopper bolt 98.

Thus, the pit cover supporting mechanism 90 of CHDY7 further includes a stopper bolt 98 as a height regulating member. Therefore, the amount of deflection (amount of contraction) in the spring expansion and contraction direction D8 of the four reaction force adjusting springs 93 is mechanically limited by the stopper bolt 98.

Therefore, the stopper bolt 98 can reliably prevent the four reaction force adjustment springs 93 from fatigue failure due to the load exceeding the limit of the spring constant SR0, and the four reaction force adjustment springs 93 can be protected.

In addition, when the stopper bolt 98 is not provided, since the amount of deflection (amount of deformation) of the four reaction force adjusting springs 93 is increased more than necessary, there is a possibility that the pit cover beam 10 supported by the pit cover supporting mechanism 90 interferes with a part of the under pit equipment 22. This is because the interval between the pit cover support mechanism 90 and the under-pit equipment 22 is likely to be about 10 mm.

Therefore, the pit cover supporting mechanism 90 can reliably avoid interference with the under pit equipment 22 due to the deflection of the four reaction force adjusting springs 93 by the stopper bolt 98, and protect the under pit equipment 22.

In this way, the pit cover supporting mechanism 90 of CHDY7 can protect the four reaction force adjusting springs 93 and the pit equipment 22 by providing the stopper bolts 98.

The receiving roller 91 of the pit cover supporting mechanism 90 is rotatably attached to the roller supporting bracket 92 with the connecting pin 94 (predetermined center axis) as a rotation axis.

Since the receiving roller 91 can rotate about the connecting pin 94 as a rotation axis, damage due to contact between the receiving roller 91 and the pit cover beam 10 can be further reduced.

Further, since the receiving roller 91 can rotate, even when the movable pit covers 2A and 2B move in the Y direction (first direction), the movable pit covers 2A and 2B can be stably supported by the pit cover beam 10.

The CHDY7 of the present embodiment includes two pit cover supporting mechanisms 90A and two pit cover supporting mechanisms 90B.

That is, the combination of the pit

cover supporting mechanisms

90A and 90B is configured to be 2 units, so that the movable pit covers 2A and 2B can be supported more stably by the CHDY 7.

< Others >

In the CHDY7 of the present embodiment, the under-pit device 22 is provided in which the roller device 62 moves in accordance with the positions of the pair of rear wheels 52, and the pit cover support mechanism 90 is mounted on the under-pit device 22.

For example, the following first modification can be considered: a front wheel pit equipment (a modified equipment of pit equipment 21) in which a front wheel roller device moves in accordance with the positions of a pair of front wheels 51 is provided, and a front wheel pit cover pair of movable pit covers and a front wheel pit cover support mechanism are provided on the front wheel roller device side, in the same manner as the pit equipment 22. In the case of the first modification, the front wheel pit cover beam is provided between the pair of movable pit covers for the front wheel.

The front wheel pit cover pair is a component corresponding to the movable pit cover 2, the front wheel pit cover support mechanism is a component corresponding to the pit cover support mechanism 90, and the front wheel pit cover beam is a component corresponding to the pit cover beam 10 (the center fixed pit cover 1C). In the case of the first modification, the rear wheel under pit equipment for the pair of rear wheels 52 has a fixed structure in the same manner as the under pit equipment 21.

In addition, in the CHDY7 of the present embodiment, the

roller devices

62A and 62B are mounted to the roller device mounting member 34 in common so as to be simultaneously movable along the device moving direction D1 as the first direction.

As a second modification of CHDY7, the following configuration is conceivable: the

roller devices

62A and 62B are separately mounted on separate dedicated support tables, so that the

roller devices

62A and 62B can move independently of each other in the device moving direction D1, which is the first direction.

In this case, the pit cover supporting mechanism 90A and the movable pit cover 2A are provided so as to be movable in the machine moving direction D1 in association with only the roller device 62A, and the pit cover supporting mechanism 90B and the movable pit cover 2B are provided so as to be movable in the machine moving direction D1 in association with only the roller device 62B.

Therefore, in the second modification, the weight of the moving object can be distributed to the roller device 62A side (including the movable pit cover 2A and the pit cover support mechanism 90A) and the roller device 62B side (including the movable pit cover 2B and the pit cover support mechanism 90B).

Therefore, by dividing the motor into two motors in the first drive motor of the roller device 62A and the second drive motor of the roller device 62B, the drive capability required for each of the first and second drive motors can be reduced.

In addition to the above, the present disclosure can be modified and omitted as appropriate within the scope of the disclosure.

For example, in CHDY7, the combination of pit

cover supporting mechanisms

90A and 90B is 2 units, but a plurality of them may be 3 or more.

Claims

1. A chassis dynamometer is characterized by comprising:

a first roller device having a first roller that can be rotationally driven and that can move in a first direction;

a second roller device having a second roller that can be rotationally driven and that can move in the first direction;

a pit cover fixed to a central portion of a rectangular shape in plan view, the pit cover being located between the first and second roller devices, the rectangular shape in plan view having the first direction as a long side direction and a second direction orthogonal to the first direction as a short side direction;

a pit cover beam provided so as to cover an upper surface and a side surface of the center fixed pit cover;

first and second movable pit covers provided along the second direction with the center fixed pit cover interposed therebetween; and

first and second pit cover support mechanisms for supporting the pit cover beam from below,

the first pit cover supporting mechanism and the first movable pit cover are movable in the first direction in conjunction with movement of the first roller device, the first pit cover supporting mechanism is located below the pit cover beam during and before and after movement,

the second pit cover support mechanism and the second movable pit cover are movable in the first direction in conjunction with the movement of the second roller device, the second pit cover support mechanism is located below the pit cover beam during and before and after the movement,

a floor surface including the central fixed pit cover and a part of the first and second movable pit covers,

in the first movable pit cover, an end portion on the side of the center fixed pit cover is defined as a first center-side end portion, and in the second movable pit cover, an end portion on the side of the center fixed pit cover is defined as a second center-side end portion,

the beam for the pit cover has a first central side end supporting region that supports the first central side end and a second central side end supporting region that supports the second central side end,

the first and second pit cover support mechanisms each have a support member in which a side structure along the second direction has a barrel shape with a central portion bulging,

the support member of the first pit cover support mechanism is in contact with the first center-side end support region to support the pit cover beam, and the support member of the second pit cover support mechanism is in contact with the second center-side end support region to support the pit cover beam.

2. The chassis dynamometer machine of claim 1,

the first and second pit cover support mechanisms each include:

a support bracket;

the support member is mounted on the support bracket;

a base provided below the support bracket; and

a plurality of reaction force adjusting springs provided between the base and the support bracket, each having an elastic force in a height direction,

the support bracket is supported to be movable up and down in the height direction by the elastic force of the plurality of reaction force adjusting springs.

3. The chassis dynamometer machine of claim 2,

the first and second pit cover supporting mechanisms further respectively comprise

And a height regulating member provided on a surface of the base and regulating a height of a lower surface of the support bracket from an upper surface of the base to be not less than a predetermined height.

4. The chassis dynamometer machine of claim 2,

the support member is rotatably attached to the support bracket with a predetermined center axis as a rotation axis.

5. Chassis dynamometer according to any of the claims 1 to 4,

the first pit cover supporting mechanism includes a plurality of first pit cover supporting mechanisms,

the second pit cover supporting mechanism includes a plurality of second pit cover supporting mechanisms.