Acceleration reduction device

Abstract

Provided is an acceleration reduction device that enables two racks to rotate at substantially the same rotational speed. The acceleration reduction device is provided with: a first rack having a plurality of first teeth arranged around a first central axis; a first pinion that meshes with the first teeth; a first drive device that rotates the first pinion; a second rack having a plurality of second teeth arranged around the first central axis; a second pinion that meshes with the second teeth; a second drive device that rotates the second pinion; and a first driver that inputs a common electric signal to the first drive device and the second drive device, the pitch circle diameter of the plurality of first teeth is different from the pitch circle diameter of the plurality of second teeth, the reduction ratio of the first rack and the first pinion and the reduction ratio of the second rack and the second pinion are set so that the first rack and the second rack rotate in unison around the first central axis.

Description

Technical Field

[0001] This invention relates to an acceleration reduction device. Background Technology

[0002] When a vehicle or a transport robot is in motion, accelerations act on passengers above the seat surface of the vehicle or on objects above the top surface of the transport robot's workbench, in directions along these surfaces. Previously, research and development have been conducted on acceleration reduction devices capable of reducing these accelerations.

[0003] Acceleration reduction devices, for example, cause a component such as a seat or workbench with a surface for a person or object to sit on to swing in a pendulum motion during acceleration, deceleration, or travel on an inclined surface. Thus, the acceleration reduction device can reduce the acceleration acting on a person or object along the direction of the surface.

[0004] For example, a rack and pinion mechanism causes a component such as a seat or workbench to perform a pendulum motion. That is, a rack and pinion mechanism has an arc-shaped rack connected to the component and a pinion that rotates the rack. For example, the pinion is rotated by a drive device including a motor and a reducer, thereby rotating the arc-shaped rack.

[0005] Patent Document 1: Japanese Patent Application Publication No. 2023-104439

[0006] Alternatively, multiple rack and pinion mechanisms can be mounted together on a component such as a seat or workbench, and made to work together to produce a pendulum motion. In this case, if the distance between the central axis of the pendulum motion and the multiple racks is the same, multiple drive devices driven by a single driver can make the multiple racks rotate at approximately the same speed.

[0007] However, multiple racks are not limited to being configured such that the distances between the racks and the central axis of the pendulum's motion are approximately the same. If the distances between the central axis of the pendulum's motion and the multiple racks are different, the pitch circle diameters of the multiple racks will be different, resulting in different reduction ratios for the multiple racks and pinion mechanisms. In this case, it is not easy for a single actuator to make the multiple racks rotate at approximately the same speed. That is, the existing structure limits the configuration of the racks. Summary of the Invention

[0008] The present invention was made in view of the above, and provides an acceleration reduction device that can make the two racks rotate at approximately the same speed even when a common electrical signal is input from one driver to two drive devices, even if the distance between the central axis and the two racks is different.

[0009] The acceleration reduction device according to the present invention comprises: a first rack having a plurality of first teeth arranged about an imaginary first central axis; a first pinion meshing with the plurality of first teeth; a first drive device configured to rotate the first pinion; a second rack having a plurality of second teeth arranged about the first central axis; a second pinion meshing with the plurality of second teeth; a second drive device configured to rotate the second pinion; and a first driver that inputs a common electrical signal to the first drive device and the second drive device, thereby reducing acceleration. In the lowering device, the first rack and the second rack are separated from each other along the first axial direction along the first central axis. The pitch circle diameters of the plurality of first teeth are different from the pitch circle diameters of the plurality of second teeth. The reduction ratio of the first rack and the first pinion and the reduction ratio of the second rack and the second pinion are set such that when the first driver inputs the electrical signal to the first drive device and the second drive device, the first rack and the second rack rotate in unison with respect to the first pinion and the second pinion around the first central axis.

[0010] According to the acceleration reduction device of the present invention, even if the distance between the first central axis and the first rack and the distance between the first central axis and the second rack are different, the first rack and the second rack can rotate in unison when a common electrical signal is input from a first driver to the first driving device and the second driving device. Attached Figure Description

[0011] Figure 1 It is a schematic side view of a portion of a vehicle according to one embodiment.

[0012] Figure 2 This is a perspective view showing the acceleration reduction device according to the above embodiment.

[0013] Figure 3 This is a side view showing the acceleration reduction device according to the above embodiment.

[0014] Figure 4 This is a perspective view showing the device for reducing the acceleration of rotation by the second rotating mechanism in the above embodiment.

[0015] Figure 5 This is a schematic front view of the first rotating mechanism in the above embodiment.

[0016] Explanation of reference numerals in the attached figures

[0017] 10...Acceleration reduction device; 21...First rotating mechanism; 22...Second rotating mechanism; 41...Front support plate (first support part); 43...Front guide roller (first roller); 44...Rear support plate (second support part); 46...Rear guide roller (second roller); 51...First drive device; 55...First rack; 55c...First tooth; 56...First pinion; 61...Second drive device; 65...Second rack; 65c...Second tooth; 66... 2nd pinion; 91...3rd drive unit; 95...3rd rack; 95b...3rd tooth; 96...3rd pinion; 101...4th drive unit; 105...4th rack; 105b...4th tooth; 106...4th pinion; 111...1st driver; 112...2nd driver; Ax1...1st central axis; Ax2...2nd central axis; Axr...central axis (3rd central axis, 4th central axis); Pc1, Pc2...pitch circle. Detailed Implementation

[0018] The following is for reference Figures 1-5 An acceleration reduction device 10 according to one embodiment will be described. Furthermore, in this specification, there may be instances where multiple terms are used to describe the structural elements involved in the embodiment and their descriptions. The structural elements and their descriptions are merely examples and are not limited to the descriptions in this specification. Structural elements may be identified using names different from those used in this specification. Moreover, structural elements may also be described using terms different from those used in this specification.

[0019] Figure 1 This is a schematic side view of a portion of the vehicle 1 according to this embodiment. For example... Figure 1 As shown, the acceleration reduction device 10 of this embodiment is mounted on a vehicle 1, such as an automobile. The acceleration reduction device 10 can, for example, reduce the acceleration of occupants of the vehicle 1 in the longitudinal and lateral directions. However, the acceleration reduction device 10 is not limited to this example.

[0020] As shown in the accompanying drawings, for convenience, X-axis, Y-axis, and Z-axis are defined in this specification. The X-axis, Y-axis, and Z-axis are orthogonal to each other. The X-axis extends along the left-right direction of vehicle 1. The Y-axis extends along the front-back direction of vehicle 1. The Z-axis extends along the vertical direction of vehicle 1.

[0021] Furthermore, in this specification, the X, Y, and Z directions are defined. The X direction is along the X-axis and includes the +X direction (right) indicated by the X-axis arrow and the opposite direction of the X-axis arrow, i.e., the -X direction (left). The Y direction is along the Y-axis and includes the +Y direction (front) indicated by the Y-axis arrow and the opposite direction of the Y-axis arrow, i.e., the -Y direction (back). The Z direction is along the Z-axis and includes the +Z direction (up) indicated by the Z-axis arrow and the opposite direction of the Z-axis arrow, i.e., the -Z direction (down).

[0022] The acceleration reduction device 10 is not limited to the vehicle 1, and can also be mounted on other devices such as autonomous robots (autonomous mobile bodies). In this case, the acceleration reduction device 10 reduces the acceleration in the forward and backward and left and right directions acting on the object being carried by the autonomous robot.

[0023] like Figure 1 As shown, the vehicle 1 of this embodiment includes an acceleration reduction device 10, a floor 11, and a seat 12. The acceleration reduction device 10 is disposed between the floor 11 and the seat 12. Alternatively, the acceleration reduction device 10 may be disposed in other locations.

[0024] Floor 11 has multiple floor surfaces 11a, 11b, and 11c. Floor surface 11a is located below floor surfaces 11b and 11c. For example, a passenger in vehicle 1 places their feet on floor surface 11a. In the Y direction, floor surface 11b is located between floor surfaces 11a and 11c. Floor surface 11c is separated from floor surface 11a in the -Y direction and is located above floor surfaces 11a and 11b. For example, goods are placed on floor surface 11c.

[0025] Vehicle 1 has, for example, a battery below the floor surface 11b. The floor 11 forms a space for the battery to be installed, therefore, the floor surface 11b is formed to be higher than the floor surface 11a. Alternatively, other components such as a drive shaft or transmission shaft may be installed below the floor surface 11b.

[0026] Figure 1 The example of seat 12 is, for example, a rear seat. However, seat 12 is not limited to this example. Seat 12 has a seat surface 12a. For example, the occupant of vehicle 1 sits on seat surface 12a. Generally, seat surface 12a faces approximately in the +Z direction.

[0027] The acceleration reduction device 10 includes a first rotating mechanism 21, a second rotating mechanism 22, and an electronic control unit (ECU) 23. Alternatively, the second rotating mechanism 22 may be omitted from the acceleration reduction device 10.

[0028] The first rotating mechanism 21 is mounted on the floor 11 and sandwiched between the floor 11 and the second rotating mechanism 22. The second rotating mechanism 22 is mounted on the seat 12 and sandwiched between the seat 12 and the first rotating mechanism 21. However, the positions of the first rotating mechanism 21 and the second rotating mechanism 22 are not limited to this example. For example, the second rotating mechanism 22 could be sandwiched between the floor 11 and the first rotating mechanism 21, and the first rotating mechanism 21 could be sandwiched between the seat 12 and the second rotating mechanism 22.

[0029] Figure 2 This is a perspective view showing the acceleration reduction device 10 of this embodiment. Figure 3 This is a side view showing the acceleration reduction device 10 of this embodiment. Figure 4 This is a perspective view showing the device 10 for reducing the rotational acceleration caused by the second rotating mechanism 22 in this embodiment. Figure 5 This is a schematic front view of the first rotating mechanism 21 of this embodiment.

[0030] In this embodiment, the first rotating mechanism 21 enables the seat 12 to perform a pendulum motion approximately along the X direction (left-right direction). Specifically, the first rotating mechanism 21 enables the second rotating mechanism 22 and the seat 12 to rotate relative to the floor 11. Figure 5 The first central axis Ax1 shown rotates. The first central axis Ax1 is an imaginary central axis of rotation of seat 12.

[0031] In this embodiment, the first central axis Ax1 is located above the first rotating mechanism 21 and the second rotating mechanism 22, and extends approximately along the Y direction (the longitudinal direction of the vehicle 1). Alternatively, the first central axis Ax1 may be located below the first rotating mechanism 21 and the second rotating mechanism 22, or it may extend in other directions. For example, the first central axis Ax1 may also extend approximately along the X direction (the lateral direction of the vehicle 1). In this case, the first rotating mechanism 21 enables the seat 12 to perform a pendulum motion approximately along the Y direction (the longitudinal direction).

[0032] On the other hand, the second rotating mechanism 22 enables the seat 12 to perform a pendulum motion approximately along the Y direction (front-to-back direction). Specifically, the second rotating mechanism 22 enables the seat 12 to rotate relative to the first rotating mechanism 21. Figure 1 The second central axis Ax2 shown rotates. The second central axis Ax2 is the imaginary central axis of rotation of seat 12.

[0033] In this embodiment, the second central axis Ax2 is located above the second rotating mechanism 22 and extends approximately along the X direction. That is, the direction in which the second central axis Ax2 extends (the second axial direction) intersects (orthogonally in this embodiment) the direction along the first central axis Ax1 (the first axial direction).

[0034] The second central axis Ax2 can also be located below the second rotating mechanism 22, or it can extend in other directions. For example, if the direction in which the second central axis Ax2 extends intersects the direction along the first central axis Ax1, then the second central axis Ax2 can also extend approximately along the Y direction (the longitudinal direction of the vehicle 1). In this case, the second rotating mechanism 22 can cause the seat 12 to perform a pendulum motion approximately along the X direction (left-right direction). If the first rotating mechanism 21 causes the second rotating mechanism 22 to rotate, then the second central axis Ax2 also rotates around the first central axis Ax1.

[0035] like Figure 2 As shown, the first rotating mechanism 21 has a base 31, a front actuator 32, and a rear actuator 33. In addition, the first rotating mechanism 21 is not limited to having two actuators (front actuator 32 and rear actuator 33), and may have three or more actuators.

[0036] Base 31 has Figure 4 The front support plate (first support portion) 41, multiple front support rollers 42, multiple front guide rollers (first rollers) 43, and rear support plate (second support portion) 44 shown are included. Figure 5 The multiple rear support rollers 45 and multiple rear guide rollers (second rollers) 46 shown are shown. Figure 4 The connecting component 47 is shown.

[0037] like Figure 1 As shown, the front support plate 41 is mounted on the floor surface 11a in a manner that extends substantially in the +Z direction from the floor surface 11a of the floor 11. The front support plate 41 is, for example, arranged along the XZ plane and formed in a plate shape. Figure 3 As shown, the front support plate 41 has a rear surface 41a. The rear surface 41a is formed generally flat and generally faces the -Y direction.

[0038] like Figure 2 As shown, a plurality of front support rollers 42 are mounted on a front support plate 41. The plurality of front support rollers 42 are respectively mounted on a shaft that protrudes generally in the -Y direction from the rear surface 41a of the front support plate 41.

[0039] Each front support roller 42 is rotatable relative to the front support plate 41 about its central axis. The central axis of the front support roller 42 extends approximately along the Y direction. Each of the multiple front support rollers 42 has a bearing, enabling smooth rotation. Figure 5 As shown, multiple front support rollers 42 are arranged at intervals around the first central axis Ax1.

[0040] like Figure 2As shown, a plurality of front guide rollers 43 are mounted on a front support plate 41. The plurality of front guide rollers 43 are respectively embedded, for example, in slots that extend through the front support plate 41 generally along the Y direction. Figure 3 As shown, a portion of the front guide roller 43 protrudes approximately in the -Y direction from the rear surface 41a of the front support plate 41.

[0041] Each front guide roller 43 can rotate relative to the front support plate 41 Figure 5 The central axis (third central axis) Axr of the front guide roller 43 shown rotates. The central axis Axr extends radially orthogonal to the first central axis Ax1. Multiple front guide rollers 43 are arranged at intervals around the first central axis Ax1.

[0042] like Figure 1 As shown, the rear support plate 44 is mounted on the floor surface 11b in a manner that extends substantially in the +Z direction from the floor surface 11b of the floor 11. That is, the rear support plate 44 is separated from the front support plate 41 in a substantially -Y direction. In other words, the front support plate 41 and the rear support plate 44 are separated from each other in the direction (first axial direction) along the first central axis Ax1.

[0043] The rear support plate 44 is, for example, configured along the XZ plane and formed in a plate shape. Figure 2 As shown, the rear support plate 44 has a front surface 44a. The front surface 44a is formed generally flat and generally faces the +Y direction.

[0044] Multiple rear support rollers 45 are mounted on a rear support plate 44. The multiple rear support rollers 45 are respectively mounted on a shaft that protrudes approximately in the +Y direction from the front surface 44a of the rear support plate 44.

[0045] Each rear support roller 45 is rotatable relative to the rear support plate 44 about its central axis. The central axis of the rear support roller 45 extends approximately along the Y direction. Each of the rear support rollers 45 has a bearing, enabling smooth rotation. Figure 5 As shown, multiple rear support rollers 45 are arranged at intervals around the first central axis Ax1.

[0046] like Figure 4 As shown, a plurality of rear guide rollers 46 are mounted on a rear support plate 44. The plurality of rear guide rollers 46 are respectively embedded in grooves that extend through the rear support plate 44 in a generally Y direction. Parts of the rear guide rollers 46 protrude generally in the +Y direction from the front surface 44a of the rear support plate 44.

[0047] Each rear guide roller 46 is rotatable relative to the rear support plate 44 about its central axis (the fourth central axis) Axr. Figure 5 As shown, multiple rear guide rollers 46 are arranged around the first central axis Ax1.

[0048] like Figure 2 As shown, the connecting member 47 extends approximately in the Y direction along the floor surface 11b of the floor 11. The connecting member 47 is mounted on the front support plate 41 and the rear support plate 44. The connecting member 47 can also be mounted on the floor surface 11b.

[0049] The front actuator 32 has a first drive unit 51, a first rack and pinion mechanism 52. The first drive unit 51 may also be referred to as a motor gearbox, for example.

[0050] The first drive unit 51 is mounted on the front support plate 41. That is, the front support plate 41 supports the first drive unit 51. The first drive unit 51, for example, has... Figure 2 The motor 51a and reducer 51b shown are... Figure 5 The output shaft 51c is shown.

[0051] Motor 51a is, for example, a DC motor. Alternatively, motor 51a could be other types of motors. Reducer 51b reduces the rotational speed of the shaft of motor 51a and transmits the speed to output shaft 51c. Output shaft 51c protrudes approximately in the -Y direction from reducer 51b. Output shaft 51c passes, for example, through a hole provided in front support plate 41 and protrudes from the rear surface 41a of front support plate 41.

[0052] The first drive unit 51 causes the output shaft 51c to rotate relative to the front support plate 41 about the central axis Axm1 of the output shaft 51c. The central axis Axm1 extends in the Y direction. That is, the central axis Axm1 extends in the direction (first axial direction) of the first central axis Ax1.

[0053] The first drive unit 51 drives the first rack and pinion mechanism 52 by rotating the output shaft 51c. The first rack and pinion mechanism 52 has a first rack 55 and a first pinion 56.

[0054] like Figure 2 As shown, the first rack 55 is located between the front support plate 41 and the rear support plate 44. Alternatively, the first rack 55 may be positioned in other locations. The first rack 55 is, for example, arranged along the XZ plane and formed in a plate shape. The first rack 55 has a front surface 55a, a lower edge 55b, and a plurality of first teeth 55c.

[0055] The front surface 55a is formed in a generally flat manner and is generally oriented in the +Y direction. For example... Figure 3 As shown, the front surface 55a of the first rack 55 is spaced apart from the rear surface 41a of the front support plate 41 and faces each other. In this embodiment, the front surface 55a is separated from the front guide roller 43. Alternatively, the plurality of front guide rollers 43 may always be in contact with the front surface 55a.

[0056] like Figure 5 As shown, the lower edge 55b is located at the radially outer end of the first rack 55. The lower edge 55b extends in an arc shape around the first central axis Ax1. In this embodiment, the lower edge 55b generally faces the -Z direction.

[0057] Multiple first teeth 55c protrude radially outward from the lower edge 55b. That is, multiple first teeth 55c protrude approximately in the -Z direction (downward) from the lower edge 55b. Multiple first teeth 55c are arranged around the first central axis Ax1. The lower edge 55b forms the tooth root of multiple first teeth 55c.

[0058] A groove 58 is provided on the first rack 55. The groove 58 is recessed approximately in the -Y direction from the front surface 55a of the first rack 55 and extends in an arc shape around the first central axis Ax1. The groove 58 may also extend approximately through the first rack 55 in the Y direction.

[0059] A plurality of front support rollers 42 are housed in the slot 58. The front support rollers 42 support the first rack 55 by abutting against the inner surface of the slot 58. The plurality of front support rollers 42 are arranged about a first central axis Ax1, and the slot 58 extends about the first central axis Ax1, so the first rack 55 can rotate about the first central axis Ax1 relative to the base 31.

[0060] The first pinion 56 is mounted on the output shaft 51c of the first drive unit 51. Therefore, the central axis Axm1 of the output shaft 51c is also the central axis of the first pinion 56. The first drive unit 51 rotates the output shaft 51c, causing the first pinion 56 to rotate about the central axis Axm1 of the output shaft 51c.

[0061] The first pinion 56 has an outer peripheral surface 56a and a plurality of pinion teeth 56b. The outer peripheral surface 56a is a generally cylindrical curved surface extending along the central axis Axm1 of the output shaft 51c. The plurality of pinion teeth 56b protrude from the outer peripheral surface 56a in a manner arranged around the central axis Axm1. The outer peripheral surface 56a forms the tooth root of the plurality of pinion teeth 56b.

[0062] In this embodiment, the first pinion 56 is located below the first rack 55. The plurality of pinion teeth 56b of the first pinion 56 mesh with the plurality of first teeth 55c of the first rack 55. Therefore, if the first drive device 51 rotates the output shaft 51c, the first pinion 56 rotates, and the first rack 55 rotates (oscillates) relative to the first pinion 56 about the first central axis Ax1. Alternatively, the first pinion 56 may be positioned above the first rack 55 or in other positions depending on the direction in which the first teeth 55c are facing.

[0063] like Figure 3As shown, the rear actuator 33 has a second drive unit 61, a second rack and pinion mechanism 62. The second drive unit 61 may also be referred to as a motor gearbox, for example.

[0064] The second drive unit 61 is mounted on the rear support plate 44. That is, the rear support plate 44 supports the second drive unit 61. The second drive unit 61, for example, has... Figure 3 The motor 61a and reducer 61b shown are... Figure 5 The output shaft 61c is shown.

[0065] Motor 61a is, for example, the same DC motor as motor 51a of the first drive unit 51. Reducer 61b is, for example, the same reducer 51b of the first drive unit 51. However, motor 61a and reducer 61b are not limited to this example.

[0066] The reducer 61b reduces the rotational speed of the shaft of the motor 61a and transmits the speed to the output shaft 61c. The output shaft 61c protrudes approximately in the +Y direction from the reducer 61b. The output shaft 61c protrudes from the front surface 44a of the rear support plate 44, for example, through a hole provided in the rear support plate 44.

[0067] The second drive unit 61 causes the output shaft 61c to rotate relative to the rear support plate 44 about the central axis Axm2 of the output shaft 61c. For example... Figure 5 As shown, the central axis Axm2 extends along the Y direction. That is, the central axis Axm2 extends along the direction in which the first central axis Ax1 extends (the first axial direction).

[0068] The second drive unit 61 drives the second rack and pinion mechanism 62 by rotating the output shaft 61c. The second rack and pinion mechanism 62 has a second rack 65 and a second pinion 66.

[0069] like Figure 2 As shown, the second rack 65 is located between the front support plate 41 and the rear support plate 44. Alternatively, the second rack 65 can be positioned in other locations. The second rack 65 is separated from the first rack 55 in the -Y direction. That is, the first rack 55 and the second rack 65 are separated from each other in the direction along the first central axis Ax1 (the first axial direction). Furthermore, the first central axis Ax1 extends in the Y direction (front-rear direction), therefore, the first rack 55 and the second rack 65 are separated from each other in the horizontal direction.

[0070] The second rack 65 is, for example, arranged along the XZ plane and formed in a plate shape. The second rack 65 has Figure 3 The rear surface 65a shown Figure 5 The upper edge 65b and multiple second teeth 65c are shown.

[0071] like Figure 3 As shown, the rear surface 65a is formed generally flat and generally faces the -Y direction. The rear surface 65a of the second rack 65 is spaced apart from the front surface 44a of the rear support plate 44 and faces each other. In this embodiment, the rear surface 65a is separated from the rear guide roller 46. Alternatively, the plurality of rear guide rollers 46 may always be in contact with the rear surface 65a.

[0072] like Figure 5 As shown, the upper edge 65b is located at the radially inner end of the second rack 65. The upper edge 65b extends in an arc shape around the first central axis Ax1. In this embodiment, the upper edge 65b generally faces the +Z direction.

[0073] Multiple second teeth 65c protrude radially inward from the upper edge 65b. That is, multiple second teeth 65c protrude approximately in the +Z direction (upward) from the upper edge 65b. Multiple second teeth 65c are arranged around the first central axis Ax1. The upper edge 65b forms the tooth root of multiple second teeth 65c.

[0074] A groove 68 is provided on the second rack 65. The groove 68 is recessed approximately in the +Y direction from the rear surface 65a of the second rack 65 and extends in an arc shape around the first central axis Ax1. The groove 68 may also extend approximately through the second rack 65 in the Y direction.

[0075] A plurality of rear support rollers 45 are housed in the groove 68. The rear support rollers 45 support the second rack 65 by abutting against the inner surface of the groove 68 that defines the second rack 65. The plurality of rear support rollers 45 are arranged about a first central axis Ax1, and the groove 68 extends about the first central axis Ax1, so the second rack 65 can rotate relative to the base 31 about the first central axis Ax1.

[0076] The second pinion 66 is mounted on the output shaft 61c of the second drive unit 61. Therefore, the central axis Axm2 of the output shaft 61c is also the central axis of the second pinion 66. The second drive unit 61 rotates the output shaft 61c, causing the second pinion 66 to rotate about the central axis Axm2 of the output shaft 61c.

[0077] The second pinion 66 has an outer peripheral surface 66a and a plurality of pinion teeth 66b. The outer peripheral surface 66a is a generally cylindrical curved surface extending along the central axis Axm2 of the output shaft 61c. The plurality of pinion teeth 66b protrude from the outer peripheral surface 66a in a manner arranged around the central axis Axm2. The outer peripheral surface 66a forms the tooth root of the plurality of pinion teeth 66b.

[0078] In this embodiment, the second pinion 66 is located above the second rack 65. The plurality of pinion teeth 66b of the second pinion 66 mesh with the plurality of second teeth 65c of the second rack 65. Therefore, if the second drive device 61 rotates the output shaft 61c, the second pinion 66 rotates, and the second rack 65 rotates (oscillates) relative to the second pinion 66 about the first central axis Ax1. Alternatively, the second pinion 66 may also be positioned below the second rack 65 or in other positions depending on the direction in which the second teeth 65c are facing.

[0079] Furthermore, in this embodiment, the central axis Axm1 of the output shaft 51c of the first drive device 51 and the central axis Axm2 of the output shaft 61c of the second drive device 61 are located below the first central axis Ax1. The central axis Axm2 is located on the straight line connecting the first central axis Ax1 and the central axis Axm1. That is, the first central axis Ax1, the central axis Axm1, and the central axis Axm2 are arranged in a straight line radially. Alternatively, the central axes Axm1 and Axm2 may be arranged in other positions.

[0080] The plurality of first teeth 55c of the first rack 55 and the plurality of second teeth 65c of the second rack 65 are arranged around the first central axis Ax1. However, the diameter of the pitch circle Pc1 of the plurality of first teeth 55c is different from the diameter of the pitch circle Pc2 of the plurality of second teeth 65c.

[0081] In this embodiment, the first rack 55 is located below the second rack 65. Therefore, the plurality of first teeth 55c of the first rack 55 are farther away from the first central axis Ax1 than the plurality of second teeth 65c of the second rack 65. That is, the diameter of the pitch circle Pc1 is larger than the diameter of the pitch circle Pc2.

[0082] The reduction ratio i1 of the first rack and pinion mechanism 52 is set to be approximately equal to the reduction ratio i2 of the second rack and pinion mechanism 62. Specifically, it is preferable that the difference between the reduction ratio i1 of the first rack 55 and the first pinion 56 and the reduction ratio i2 of the second rack 65 and the second pinion 66 is set to be less than 1% of the reduction ratio i1. Alternatively, the difference between the reduction ratio i1 and the reduction ratio i2 may be more than 1%.

[0083] For example, in the calculation of reduction ratio i1, the number of teeth of the plurality of first teeth 55c of the first rack 55 is 689. Furthermore, the number of teeth used in the calculation of reduction ratio i1 for the plurality of first teeth 55c is not the actual number of teeth of the first teeth 55c, but rather the number of teeth of the first teeth 55c when the plurality of first teeth 55c are arranged in a 360° configuration around the first central axis Ax1. The number of teeth of the first teeth 55c can be calculated, for example, based on the diameter of the pitch circle Pc1 and the pitch of the plurality of first teeth 55c.

[0084] The number of teeth 56b of the first pinion 56 is 20. Therefore, the reduction ratio i1 of the first rack 55 and the first pinion 56 is 34.45 (34.45:1).

[0085] In the calculation of reduction ratio i2, the number of teeth of the plurality of second teeth 65c of the second rack 65 is 585. Furthermore, the number of teeth used in the calculation of reduction ratio i2 for the plurality of second teeth 65c is not the actual number of teeth of the second teeth 65c, but rather the number of teeth of the second teeth 65c when the plurality of second teeth 65c are arranged in a 360° configuration around the first central axis Ax1. The number of teeth of the second teeth 65c can be calculated, for example, based on the diameter of the pitch circle Pc2 and the pitch of the plurality of second teeth 65c.

[0086] The number of teeth 66b of the second pinion 66 is 17. Therefore, the reduction ratio i2 of the second rack 65 and the second pinion 66 is approximately 34.41 (34.41:1).

[0087] On one hand, the difference between reduction ratio i1 and reduction ratio i2 is approximately 0.04. On the other hand, 1% of reduction ratio i1 is approximately 0.34. As mentioned above, the difference between reduction ratio i1 and reduction ratio i2 is less than 1% of reduction ratio i1. Furthermore, the number of teeth of the plurality of first teeth 55c, the plurality of pinion teeth 56b, the plurality of second teeth 65c, the plurality of pinion teeth 66b, reduction ratio i1, and reduction ratio i2 described above are merely examples and are not intended to limit the quantity or reduction ratio.

[0088] like Figure 4 As shown, the second rotating mechanism 22 has a seat base 71, a right actuator 72, and a left actuator 73. In addition, the second rotating mechanism 22 is not limited to having two actuators (right actuator 72 and left actuator 73), and may have three or more actuators.

[0089] The seat base 71 has a base frame 81, multiple support rollers 82, and a seat frame 83.

[0090] The base frame 81 is disposed between the first rack 55 and the second rack 65, and is connected to the first rack 55 and the second rack 65. That is, the base frame 81 is mounted on the first rotating mechanism 21.

[0091] Each support roller 82 is mounted on the base frame 81 in a manner that allows it to rotate about its central axis. The central axis of the support roller 82 extends in the direction (second axial direction) along the second central axis Ax2. The multiple support rollers 82 have bearings and are capable of smooth rotation. The multiple support rollers 82 are arranged about the second central axis Ax2.

[0092] The seat frame 83 has a right guide rail 85, a left guide rail 86, multiple beams 87, and a wire frame 88. The right guide rail 85 and the left guide rail 86 are each arranged in a manner substantially orthogonal to the direction (second axial direction) along the second central axis Ax2 and are formed in a plate-like shape. The right guide rail 85 separates from the left guide rail 86 substantially in the +X direction. That is, the right guide rail 85 and the left guide rail 86 are separated from each other in the direction (second axial direction) along the second central axis Ax2.

[0093] Multiple beams 87 connect the right guide rail 85 to the left guide rail 86 respectively. A wire frame 88 is mounted on the right guide rail 85 and the left guide rail 86 and is integrated with the seat 12. The wire frame 88, for example, holds the seat cushion of the seat 12.

[0094] Grooves 89 are provided on the right guide rail 85 and the left guide rail 86 respectively. Grooves 89 extend around the second central axis Ax2. Multiple support rollers 82 are respectively housed in the two grooves 89.

[0095] Multiple support rollers 82 support the right guide rail 85 and the left guide rail 86 by abutting against the inner surface that defines the groove 89. The multiple support rollers 82 are arranged about a second central axis Ax2 and the groove 89 extends about the second central axis Ax2, so the right guide rail 85 and the left guide rail 86 can rotate about the second central axis Ax2 relative to the base frame 81.

[0096] The right actuator 72 has a third drive unit 91 and a third rack and pinion mechanism 92. The third drive unit 91 may also be referred to as a motor gearbox, for example.

[0097] The third drive unit 91 is mounted on the right guide rail 85. The third drive unit 91 includes, for example, a motor, a reducer, and an output shaft. The reducer transmits the rotation of the motor shaft to the output shaft.

[0098] The third drive unit 91 drives the third rack and pinion mechanism 92 by rotating the output shaft of the third drive unit 91. The third rack and pinion mechanism 92 has a third rack 95 and a third pinion 96.

[0099] The third rack 95 is mounted on the base frame 81. The third rack 95 is located between the right guide rail 85 and the left guide rail 86. Alternatively, the third rack 95 can be positioned in other locations. The third rack 95 is, for example, configured orthogonal to the direction along the second central axis Ax2 (the second axial direction) and formed in a plate shape. The third rack 95 has an upper edge 95a and a plurality of third teeth 95b.

[0100] The upper edge 95a extends in an arc around the second central axis Ax2 and faces the second central axis Ax2. In this embodiment, the upper edge 95a generally faces the +Z direction. A plurality of third teeth 95b protrude from the upper edge 95a toward the second central axis Ax2. That is, the plurality of third teeth 95b protrude generally in the +Z direction (upward direction) from the upper edge 95a. The plurality of third teeth 95b are arranged around the second central axis Ax2. The upper edge 95a forms the tooth root of the plurality of third teeth 95b.

[0101] The third pinion 96 is mounted on the output shaft of the third drive unit 91. The third drive unit 91 causes the third pinion 96 to rotate about its central axis. The central axis of the third pinion 96 extends in the direction (second axial direction) along the second central axis Ax2.

[0102] In this embodiment, the third pinion 96 is located above the third rack 95. Multiple teeth of the third pinion 96 mesh with multiple third teeth 95b of the third rack 95. Therefore, if the third drive device 91 rotates the third pinion 96, the third rack 95 rotates (oscillates) relative to the third pinion 96 about the second central axis Ax2. Alternatively, the third pinion 96 may be positioned below the third rack 95 or in other locations depending on the direction in which the third teeth 95b are facing.

[0103] The left actuator 73 has a fourth drive unit 101 and a fourth rack and pinion mechanism 102. The fourth drive unit 101 may also be referred to as a motor gearbox, for example.

[0104] The fourth drive unit 101 is mounted on the left guide rail 86. The fourth drive unit 101 includes, for example, a motor, a reducer, and an output shaft. The motor and reducer of the fourth drive unit 101 are the same as those of the third drive unit 91. However, the fourth drive unit 101 is not limited to this example.

[0105] The fourth drive unit 101 drives the fourth rack and pinion mechanism 102 by rotating the output shaft of the fourth drive unit 101. The fourth rack and pinion mechanism 102 has a fourth rack 105 and a fourth pinion 106.

[0106] The fourth rack 105 is mounted on the base frame 81. Furthermore, as described above, the third rack 95 is also mounted on the base frame 81. That is, the first rotating mechanism 21 is mounted on the second rotating mechanism 22. If the first rack 55 and the second rack 65 rotate relative to the base 31 about the first central axis Ax1, then the second rotating mechanism 22 also rotates relative to the base 31 about the first central axis Ax1.

[0107] The fourth rack 105 is located between the right guide rail 85 and the left guide rail 86. Alternatively, the fourth rack 105 can be positioned in other locations. The fourth rack 105 is separated from the third rack 95 in the -X direction. That is, the third rack 95 and the fourth rack 105 are separated from each other in the direction along the second central axis Ax2 (the second axial direction). Furthermore, the second central axis Ax2 extends approximately along the X direction (left-right direction), therefore, the third rack 95 and the fourth rack 105 are separated from each other in the horizontal direction.

[0108] The fourth rack 105 is configured, for example, orthogonal to the direction (second axial direction) along the second central axis Ax2 and formed in a plate shape. The fourth rack 105 has an upper edge 105a and a plurality of fourth teeth 105b.

[0109] The upper edge 105a extends in an arc around the second central axis Ax2 and faces the second central axis Ax2. In this embodiment, the upper edge 105a generally faces the +Z direction. A plurality of fourth teeth 105b protrude from the upper edge 105a toward the second central axis Ax2. That is, the plurality of fourth teeth 105b protrude generally in the +Z direction (upward) from the upper edge 105a. The plurality of fourth teeth 105b are arranged around the second central axis Ax2. The upper edge 105a forms the tooth root of the plurality of fourth teeth 105b.

[0110] The fourth pinion 106 is mounted on the output shaft of the fourth drive unit 101. The fourth drive unit 101 causes the fourth pinion 106 to rotate about its central axis. The central axis of the fourth pinion 106 extends in the direction (second axial direction) along the second central axis Ax2.

[0111] In this embodiment, the fourth pinion 106 is located above the fourth rack 105. Multiple teeth of the fourth pinion 106 mesh with multiple fourth teeth 105b of the fourth rack 105. Therefore, if the fourth drive device 101 rotates the fourth pinion 106, the fourth rack 105 rotates (oscillates) relative to the fourth pinion 106 about the second central axis Ax2. Alternatively, the fourth pinion 106 may be positioned below the fourth rack 105 or in other locations depending on the direction in which the fourth teeth 105b are facing.

[0112] In this embodiment, the pitch circle diameters of the plurality of third teeth 95b are equal to the pitch circle diameters of the plurality of fourth teeth 105b. Furthermore, the reduction ratios of the third rack 95 and the third pinion 96 are approximately equal to the reduction ratios of the fourth rack 105 and the fourth pinion 106.

[0113] As a variation, the pitch circle diameters of the plurality of third teeth 95b may be different from those of the plurality of fourth teeth 105b. In this case, it is preferable that the difference between the reduction ratio of the third rack 95 and the third pinion 96 and the reduction ratio of the fourth rack 105 and the fourth pinion 106 is set to be less than 1% of the reduction ratio of the third rack 95 and the third pinion 96. Alternatively, the difference between the reduction ratio of the third rack 95 and the third pinion 96 and the reduction ratio of the fourth rack 105 and the fourth pinion 106 may be more than 1%.

[0114] like Figure 1 As shown, ECU 23 has a first driver 111 and a second driver 112. ECU 23 also includes, for example, a processing unit such as a CPU, a memory such as ROM and RAM, and an acceleration sensor. The processing unit controls the first driver 111 and the second driver 112 based on a program read from the memory.

[0115] Motor 51a of the first drive unit 51 and motor 61a of the second drive unit 61 are connected in parallel with the first driver 111. Therefore, the first driver 111 inputs a common electrical signal to motor 51a of the first drive unit 51 and motor 61a of the second drive unit 61. For example, the first driver 111 inputs a common voltage (voltage signal) to motor 51a of the first drive unit 51 and motor 61a of the second drive unit 61.

[0116] The motors of the third drive unit 91 and the fourth drive unit 101 are connected in parallel with the second driver 112. Therefore, the second driver 112 inputs a common electrical signal to the motors of the third drive unit 91 and the fourth drive unit 101. For example, the second driver 112 inputs a common voltage (voltage signal) to the motors of the third drive unit 91 and the fourth drive unit 101.

[0117] ECU23 obtains the acceleration acting on vehicle 1, for example, from an acceleration sensor. Based on the acceleration acting on vehicle 1 in the X direction, ECU23 inputs a common voltage from the first driver 111 to motor 51a of the first drive unit 51 and motor 61a of the second drive unit 61.

[0118] The first drive unit 51 is driven by the input voltage, causing the first pinion 56 to rotate. As a result, the first rack 55 rotates about the first central axis Ax1. Similarly, the second drive unit 61 is driven by the input voltage, causing the second pinion 66 to rotate. As a result, the second rack 65 rotates about the first central axis Ax1.

[0119] The motor 51a of the first drive unit 51 is the same motor as the motor 61a of the second drive unit 61. Furthermore, the reducer 51b of the first drive unit 51 is the same reducer as the reducer 61b of the second drive unit 61. Also, the first drive unit 51 and the second drive unit 61 receive a common voltage. Therefore, the rotational speed of the first pinion 56 driven by the first drive unit 51 is approximately the same as the rotational speed of the second pinion 66 driven by the second drive unit 61.

[0120] The reduction ratio i1 of the first rack 55 and the first pinion 56 is approximately equal to the reduction ratio i2 of the second rack 65 and the second pinion 66. Therefore, the rotational speed of the first rack 55 is approximately the same as the rotational speed of the second rack 65. Thus, the first rack 55 and the second rack 65 can rotate in unison around the first central axis Ax1. In other words, the first rack 55 and the second rack 65 can rotate parallel to each other around the first central axis Ax1, preventing twisting.

[0121] For example, when the first drive unit 51 and the second drive unit 61 are started, there may be a situation where the load acting on the first drive unit 51 is different from the load acting on the second drive unit 61. In this case, the rotational speed of the first pinion 56 is different from that of the second pinion 66. Therefore, the rotational speed of the first rack 55 is different from that of the second rack 65, and the first rack 55 and the second rack 65 are inclined obliquely relative to the first central axis Ax1.

[0122] If the first rack 55 is tilted, a portion of the first rack 55 will approach the front support plate 41. In this case, the front guide roller 43 contacts the front surface 55a of the first rack 55, supporting the first rack 55.

[0123] The front guide roller 43 restricts the first rack 55 from approaching the front support plate 41 by contacting the first rack 55, which rotates about the first central axis Ax1, and the front guide roller 43 rolls on the front surface 55a of the first rack 55. The front guide roller 43 keeps the first rack 55 separated from the front support plate 41, allowing the first rack 55 to rotate smoothly about the first central axis Ax1.

[0124] Furthermore, if the second rack 65 is tilted, a portion of the second rack 65 will approach the rear support plate 44. In this case, the rear guide roller 46 contacts the rear surface 65a of the second rack 65, providing support for the second rack 65.

[0125] The rear guide roller 46 restricts the second rack 65 from approaching the rear support plate 44 by contacting the second rack 65, which rotates about the first central axis Ax1, and rolls on the rear surface 65a of the second rack 65. The rear guide roller 46 keeps the second rack 65 separated from the rear support plate 44, allowing the second rack 65 to rotate smoothly about the first central axis Ax1.

[0126] By continuously rotating the first rack 55 and the second rack 65 around the first central axis Ax1, the loads acting on the first drive unit 51 and the second drive unit 61 become approximately equal over time. Therefore, the rotational speed of the first rack 55 is approximately the same as that of the second rack 65, and the tilting of the first rack 55 and the second rack 65 is eliminated. Alternatively, the first rack 55 and the second rack 65 may remain tilted relative to the first central axis Ax1.

[0127] ECU23 drives the first drive unit 51 and the second drive unit 61 according to the acceleration acting on vehicle 1 in the X direction, thereby rotating the first rack 55 and the second rack 65 to a desired angle about the first central axis Ax1. As a result, the second rotating mechanism 22 and the seat 12 also rotate about the first central axis Ax1.

[0128] By rotating the seat 12, the seat surface 12a tilts. As a result, the acceleration in the X direction acting on the occupant on the seat surface 12a is dispersed into acceleration along the seat surface 12a and acceleration in a direction orthogonal to the seat surface 12a. Therefore, the acceleration acting on the occupant on the seat surface 12a in the direction along the seat surface 12a decreases, and the acceleration felt by the occupant in the X direction decreases.

[0129] Furthermore, based on the acceleration acting on the vehicle 1 in the Y direction, the ECU23 inputs a common voltage from the second driver 112 to the motors of the third drive unit 91 and the fourth drive unit 101.

[0130] The third drive unit 91 is driven by the input voltage, causing the third pinion 96 to rotate. This causes the third rack 95 to rotate about the second central axis Ax2. Furthermore, the fourth drive unit 101 is driven by the input voltage, causing the fourth pinion 106 to rotate. This causes the fourth rack 105 to rotate about the second central axis Ax2.

[0131] The motor in the third drive unit 91 is the same as the motor in the fourth drive unit 101. Furthermore, the reducer in the third drive unit 91 is the same as the reducer in the fourth drive unit 101. Also, the third drive unit 91 and the fourth drive unit 101 receive a common voltage. Therefore, the rotational speed of the third pinion 96 driven by the third drive unit 91 is approximately the same as the rotational speed of the fourth pinion 106 driven by the fourth drive unit 101.

[0132] The reduction ratio of the third rack 95 and the third pinion 96 is approximately equal to that of the fourth rack 105 and the fourth pinion 106. Therefore, the rotational speed of the third rack 95 is approximately the same as that of the fourth rack 105. Consequently, the third rack 95 and the fourth rack 105 can rotate in unison around the second central axis Ax2. In other words, the third rack 95 and the fourth rack 105 can rotate parallel to each other around the second central axis Ax2, preventing twisting.

[0133] ECU23 drives the third drive unit 91 and the fourth drive unit 101 according to the acceleration acting on the vehicle 1 in the Y direction, causing the third rack 95 and the fourth rack 105 to rotate to a desired angle about the second central axis Ax2. As a result, the seat 12 also rotates about the second central axis Ax2.

[0134] As the seat 12 rotates, the seat surface 12a tilts. Consequently, the acceleration in the Y direction acting on the occupant on the seat surface 12a is dispersed into acceleration along the seat surface 12a and acceleration in a direction orthogonal to the seat surface 12a. Therefore, the acceleration acting on the occupant on the seat surface 12a decreases, and the acceleration felt by the occupant in the Y direction decreases.

[0135] In the vehicle 1 described above, the acceleration reduction device 10 includes a first rack 55, a first pinion 56, a first drive unit 51, a second rack 65, a second pinion 66, a second drive unit 61, and a first driver 111. The first rack 55 has a plurality of first teeth 55c arranged around an imaginary first central axis Ax1. The first pinion 56 meshes with the plurality of first teeth 55c. The first drive unit 51 is configured to rotate the first pinion 56. The second rack 65 has a plurality of second teeth 65c arranged around the first central axis Ax1. The second pinion 66 meshes with the plurality of second teeth 65c. The second drive unit 61 is configured to rotate the second pinion 66. The first driver 111 inputs a common electrical signal to the first drive unit 51 and the second drive unit 61. The first rack 55 and the second rack 65 are separated from each other along a first axial direction along the first central axis Ax1. The diameter of the pitch circle Pc1 of the plurality of first teeth 55c is different from the diameter of the pitch circle Pc2 of the plurality of second teeth 65c. The reduction ratio i1 of the first rack 55 and the first pinion 56 and the reduction ratio i2 of the second rack 65 and the second pinion 66 are set such that when the first driver 111 inputs an electrical signal to the first drive device 51 and the second drive device 61, the first rack 55 and the second rack 65 rotate in unison with respect to the first pinion 56 and the second pinion 66 about the first central axis Ax1.

[0136] According to the above structure, a common electrical signal is input to the first drive unit 51 and the second drive unit 61 via a first driver 111, so that the first rack 55 and the second rack 65 can rotate around the first central axis Ax1 at approximately the same speed. Therefore, when a component such as a seat 12 or a worktable is mounted on the first rack 55 and the second rack 65, the component can rotate around the first central axis Ax1 without twisting. Furthermore, the acceleration reduction device 10 enables two rack and pinion mechanisms with different pitch circle diameters to be driven at approximately the same speed as described above, thus increasing the freedom (flexibility) of the layout of various components. Moreover, compared to the case where the first rack 55 and the second rack 65 are driven by different drivers, the acceleration reduction device 10 can drive the first drive unit 51 and the second drive unit 61 with a single first driver 111, thereby reducing costs and enabling miniaturization.

[0137] The first rack 55 and the second rack 65 are separated from each other in the horizontal direction. The first pinion 56 is located above or below the first rack 55. The second pinion 66 is located above or below the second rack 65.

[0138] According to the above structure, the first rack 55 and the first pinion 56 are not arranged in a horizontal direction, and neither are the second rack 65 and the second pinion 66. Therefore, the acceleration reduction device 10 can be miniaturized in the horizontal direction compared to the case where the rack and pinion are arranged in a horizontal direction.

[0139] The first rack 55 is located below the second rack 65. The first pinion 56 is located below the first rack 55.

[0140] According to the above structure, the first rack 55 is located below the second rack 65. Therefore, compared to the second rack 65, the first rack 55 is more likely to come into contact with liquids, such as those spilled or splashed by occupants of vehicle 1. However, the first pinion 56 is located below the first rack 55, so the plurality of first teeth 55c protrude generally downwards. Therefore, when the first rack 55 comes into contact with liquid, gravity can discharge the liquid through the gaps between the plurality of first teeth 55c.

[0141] The acceleration reduction device 10 includes a first rotating mechanism 21, a second rotating mechanism 22, and a second driver 112. The first rotating mechanism 21 has a first rack 55, a first pinion 56, a first drive device 51, a second rack 65, a second pinion 66, and a second drive device 61. The second rotating mechanism 22 has a third rack 95, a third pinion 96, a third drive device 91, a fourth rack 105, a fourth pinion 106, and a fourth drive device 101. The third rack 95 has a plurality of third teeth 95b arranged around an imaginary second central axis Ax2 and meshing with the third pinion 96. The third drive device 91 is configured to rotate the third pinion 96. The fourth rack 105 has a plurality of fourth teeth 105b arranged around the second central axis Ax2 and meshing with the fourth pinion 106. The fourth drive device 101 is configured to rotate the fourth pinion 106. The second driver 112 inputs a common electrical signal to the third driver 91 and the fourth driver 101. The second central axis Ax2 extends along a second axis that intersects the first axis. The third rack 95 and the fourth rack 105 are separated from each other along the second axis. The first rotating mechanism 21 is mounted on the second rotating mechanism.

[0142] According to the above structure, by combining the two rotating mechanisms (first rotating mechanism 21 and second rotating mechanism 22), the acceleration reduction device 10 can rotate a component such as the seat 12 about two axes, thereby more effectively reducing the acceleration acting on a person (passenger) or object on the component. Furthermore, at least one of the two rotating mechanisms (first rotating mechanism 21) can drive two rack and pinion mechanisms with different pitch circle diameters at approximately the same rotational speed as described above, thus increasing the freedom (flexibility) of the layout of various components.

[0143] The acceleration reduction device 10 also includes a front support plate 41, a front guide roller 43, a rear support plate 44, and a rear guide roller 46. The front support plate 41 supports the first drive device 51. The front guide roller 43 is configured to be mounted on the front support plate 41 in a manner that allows it to rotate about a central axis Axr extending radially orthogonal to the first central axis Ax1. The front guide roller 43 restricts the approach of the first rack 55 to the front support plate 41 by contacting the first rack 55 that rotates about the first central axis Ax1, and the front guide roller 43 rolls on the front surface 55a of the first rack 55. The rear support plate 44 supports the second drive device 61. The rear guide roller 46 is configured to be mounted on the rear support plate 44 in such a way that it can rotate about a central axis Axr that extends radially orthogonal to the first central axis Ax1. The rear guide roller 46 restricts the second rack 65 from approaching the rear support plate 44 by contacting the second rack 65 that rotates about the first central axis Ax1, and the rear guide roller 46 rolls on the rear surface 65a of the second rack 65.

[0144] According to the above structure, for example, when the load acting on the first drive unit 51 is different from the load acting on the second drive unit 61, there may be a situation where the rotational speed of the first rack 55 is different from the rotational speed of the second rack 65. In this case, the first rack 55 and the second rack 65 twist relative to the first central axis Ax1, with the first rack 55 approaching the front support plate 41 and the second rack 65 approaching the rear support plate 44. The front guide roller 43, by abutting against the first rack 55 which is approaching the front support plate 41, can prevent the first rack 55 from abutting against the front support plate 41 and can guide the first rack 55 to rotate smoothly about the first central axis Ax1. That is, the front guide roller 43 can prevent the first rack 55 from abutting against the front support plate 41 and being unable to rotate. Furthermore, the rear guide roller 46, by abutting against the second rack 65 near the rear support plate 44, prevents the second rack 65 from abutting against the rear support plate 44 and guides the second rack 65 to rotate smoothly about the first central axis Ax1. That is, the rear guide roller 46 can prevent the second rack 65 from abutting against the rear support plate 44 and being unable to rotate. Even if the first rack 55 and the second rack 65 are twisted relative to the first central axis Ax1, the uneven load acting on the first rack 55 and the second rack 65 can be eliminated over time by the continuous rotation of the first rack 55 and the second rack 65. Therefore, the acceleration reduction device 10 can eventually make the rotational speed of the first rack 55 approximately the same as the rotational speed of the second rack 65. In addition, the acceleration reduction device 10 may also have any combination of the front support plate 41 and the front guide roller 43 and the rear support plate 44 and the rear guide roller 46. Alternatively, for example, a guide roller that rolls on the surface of the third rack 95 may be provided on the right guide rail 85, and a guide roller that rolls on the surface of the fourth rack 105 may be provided on the left guide rail 86.

[0145] The first central axis Ax1, the central axis Axm1 of the first pinion 56, and the central axis Axm2 of the second pinion 66 are arranged in a straight line in a radial direction orthogonal to the first central axis Ax1.

[0146] The first rack 55 is configured such that, under normal circumstances, the first pinion 56 is located at the center of the first rack 55. Furthermore, the second rack 65 is configured such that, under normal circumstances, the second pinion 66 is located at the center of the second rack 65. Therefore, according to the above structure, the acceleration reduction device 10 can prevent the first rack 55 and the second rack 65 from being misaligned around the first central axis Ax1, for example, by reducing the width of the acceleration reduction device 10 in the X direction.

[0147] The above embodiments of the present invention are illustrated, but these embodiments and modifications are merely examples and are not intended to limit the scope of the invention. The above embodiments and modifications can be implemented in various other ways, and various omissions, substitutions, combinations, and changes can be made without departing from the spirit of the invention. Furthermore, the structure and shape of each embodiment and modification can be partially changed.

Claims

1. An acceleration reduction device, characterized in that, have: The first rack has a plurality of first teeth arranged around an imaginary first central axis; The first pinion meshes with the plurality of first teeth; The first drive device is configured to rotate the first pinion; The second rack has a plurality of second teeth arranged around the first central axis; The second pinion meshes with the plurality of second teeth; The second drive mechanism is configured to rotate the second pinion; as well as The first driver inputs a common electrical signal to both the first driving device and the second driving device. The first rack and the second rack are separated from each other along a first axial direction along the first central axis. The pitch circle diameters of the plurality of first teeth are different from the pitch circle diameters of the plurality of second teeth. The reduction ratio of the first rack and the first pinion and the reduction ratio of the second rack and the second pinion are set such that when the first driver inputs the electrical signal to the first driving device and the second driving device, the first rack and the second rack rotate in unison with respect to the first pinion and the second pinion around the first central axis.

2. The acceleration reduction device according to claim 1, characterized in that, The first rack and the second rack are separated from each other in the horizontal direction. The first pinion is located above or below the first rack. The second pinion is located above or below the second rack.

3. The acceleration reduction device according to claim 2, characterized in that, The first rack is located below the second rack. The first pinion is located below the first rack.

4. The acceleration reduction device according to claim 1, characterized in that, It also has: The first rotating mechanism includes the first driving device, the first pinion, the first driving device, the second rack, the second pinion, and the second driving device; The second rotating mechanism has a third rack, a third pinion, a third drive device configured to rotate the third pinion, a fourth rack, a fourth pinion, and a fourth drive device configured to rotate the fourth pinion. as well as The second driver inputs a common electrical signal to the third and fourth driver devices. The third rack has a plurality of third teeth arranged around an imaginary second central axis and meshing with the third pinion. The fourth rack has a plurality of fourth teeth arranged around the second central axis and meshing with the fourth pinion. The second central axis extends along a second axis that intersects the first axis. The third rack and the fourth rack are separated from each other along the second axis. The first rotating mechanism is mounted on the second rotating mechanism.

5. The acceleration reduction device according to claim 1, characterized in that, It also has: The first support portion supports the first drive device; The first roller is configured to be mounted on the first support in such a way that it can rotate about a third central axis extending radially orthogonal to the first central axis. The first roller restricts the first rack from approaching the first support by contacting the first rack that rotates about the first central axis, and the first roller rolls on the surface of the first rack. The second support portion supports the second drive unit; and The second roller is configured to be mounted on the second support in such a way that it can rotate about a fourth central axis extending radially orthogonal to the first central axis. The second roller restricts the second rack from approaching the second support by contacting the second rack that rotates about the first central axis, and the second roller rolls on the surface of the second rack.

Images