Distance measuring device

Abstract

A mirror (18) of a distance measuring device (1) scans light to the outside by being swung and driven by an actuator (20). The base (11) is internally provided with a reflecting mirror (18). The mirror (18) is fixed to the oscillating shafts (13, 130), and the oscillating shafts (13, 130) are rotatably supported by the base (11) with at least one end thereof protruding from the base (11). The position holding section (16) has an urging member (165) for urging the oscillating shafts (13, 130) toward one side in the axial direction, and position restricting sections (161, 132) for restricting the movement of the oscillating shafts (13) in the urging direction, and holds the axial position of the oscillating shafts (13). The contact member (31) is fixed to the swing shaft (13) on the outside of the base (11). The distance between the housing part (50) and the end of the contact member (31) on the opposite side of the biasing direction of the oscillating shaft (13) is smaller than the distance between the base (11) and the end of the mirror (18) on the opposite side of the biasing direction of the oscillating shaft (13).

Description

Cross-reference of related applications

[0001] This application is based on Japanese Patent Application No. 2023-122214, filed on July 27, 2023, the contents of which are incorporated herein by reference. Technical Field

[0002] This disclosure relates to a ranging device. Background Technology

[0003] Previously, rotary reciprocating actuators for LiDAR (Light Detection and Ranging) were known. For example, in Patent Document 1, a rotating shaft with a reflector mounted on it was rotatably mounted on the left and right walls of a base via bearings.

[0004] Existing technical documents Patent documents Patent Document 1: Japanese Patent Application Publication No. 2022-127381 Summary of the Invention

[0005] As in Patent Document 1, in a structure where a reflector is positioned between opposing walls, for example, when axial position is limited by a preload spring, the reflector may come into contact with and break from the wall under impact exceeding the load generated by the preload spring. The object of this disclosure is to provide a ranging device capable of preventing damage to the reflector.

[0006] The distance measuring device disclosed herein measures the distance to an object by scanning light outward and detecting the light reflected by the object. It includes a reflector, a base, a swing shaft, a position holding part, and a contacting part.

[0007] A reflector scans light outward by being driven to oscillate by an actuator. The reflector is housed within a base. A oscillating shaft is fixed to the reflector and supported in a oscillating manner with at least one end protruding from the base. A position holding part includes a force-applying member that applies force to one side of the oscillating shaft in the axial direction and a position limiting part that restricts movement in the direction of the applied force, thus maintaining the axial position of the oscillating shaft. An abutment member is fixed to the oscillating shaft on the outside of the base.

[0008] The portion including the base and not driven by the actuator is designated as the housing portion. The distance between the end of the abutting member on the side opposite to the direction of force application on the swing axis and the housing portion is less than the distance between the end of the reflector on the side opposite to the direction of force application on the swing axis and the base. This prevents damage to the reflector. Attached Figure Description

[0009] The foregoing and other objects, features, and advantages of this disclosure will become more apparent from the accompanying drawings and from the detailed description that follows.

[0010] Figure 1 This is a schematic diagram showing the ranging device of the first embodiment.

[0011] Figure 2 This is a cross-sectional view showing the oscillating actuator of the first embodiment.

[0012] Figure 3 This is a cross-sectional view showing the oscillating actuator of the second embodiment. Detailed Implementation

[0013] The ranging device of this disclosure will now be described with reference to the accompanying drawings. In various embodiments, substantially identical structures will be labeled with the same reference numerals and descriptions will be omitted.

[0014] (First Implementation) Figure 1 and Figure 2 This indicates the first implementation method. For example... Figure 1 As shown, the ranging device 1 is a LiDAR (Light Detection and Range) device that determines the distance to an object by illuminating it with light and detecting the reflected light from the illuminated object. The ranging device 1 is mounted, for example, on a vehicle, to detect objects present in front of the vehicle.

[0015] The ranging device 1 includes a light-emitting unit 91, a light-receiving unit 92, and a oscillating actuator 5, and is housed in a housing 93. The light-emitting unit 91 intermittently outputs a light beam B. The output light beam B is reflected by a oscillating reflector 18 and emitted outward through an optical window 94. The light-receiving unit 92 receives the reflected light from an object irradiated by the light beam B. The light detected by the light-receiving unit 92 is converted into an electrical signal for calculating the distance to the object.

[0016] like Figure 2 As shown, the oscillating actuator 5 includes a reflector section 10, an oscillating motor 20, and an encoder 30. The reflector section 10 includes a base 11, a main shaft 13, a position holding section 16, a holding member 17, and a reflector 18. The base 11 has a mounting section 111 and holding walls 112 and 113, and is integrally formed, for example, from metal. The mounting section 111 is mounted to a base housing (not shown) by bolts or the like. The holding walls 112 and 113 are erected substantially vertically at both ends of the mounting section 111.

[0017] The main shaft 13 is arranged substantially parallel to the mounting portion 111 and is rotatably supported on the base 11 by bearings 14 and 15 provided in the retaining walls 112 and 113. In this embodiment, the bearings 14 and 15 are ball bearings, but bearings other than ball bearings may also be used. The main shaft 13 extends from the bearing 15 side toward the swing motor 20 and encoder 30 side to the outer side of the base 11. Hereinafter, the swing axis direction of the main shaft 13 will be simply referred to as the "axial direction".

[0018] The position holding part 16 has an E-ring 161 and a preload spring 165, which positions the spindle 13 axially when pressed to one side in the axial direction. The E-ring 161 is located on the outer side of the bearing 14 in the axial direction and functions as an anti-disengagement component for the spindle 13.

[0019] A preload spring 165 is disposed between the rotor magnet 22 and the bearing 15, with one end abutting against the inner ring of the bearing 15 and the other end abutting against the rotor magnet 22. Other components may also be disposed between the rotor magnet 22 and the preload spring 165. The preload spring 165 acts as a pressure point on the main shaft 13 in the direction towards the encoder 30. Figure 2 Force is applied to the left side of the paper. That is, in this embodiment, the component for holding the axial position of the spindle 13 is not provided in the base 11, so there is no need to consider the optical aspects of the position holding part 16.

[0020] The retainer 17 is pressed and fixed to the main shaft 13. The reflector 18 is formed in the shape of a flat plate and is mounted on the retainer 17 in a manner symmetrical with respect to the swing axis. The retainer 17 and the reflector 18 are formed symmetrically with respect to the swing axis, thereby making the moment of inertia during swing equal in both directions.

[0021] The retainer 17 and the reflector 18 are arranged inside the base 11 with the reflector surface 181 facing the opposite side of the mounting portion 111, and are driven to swing by the swing motor 20. The reflector 18 reflects the light beam B output from the light-emitting portion 91 through the reflector surface 181, and emits the light beam B outward in a direction corresponding to the swing position of the reflector 18, thereby scanning the light beam B within a predetermined scanning range.

[0022] The oscillating motor 20 is disposed on one side of the reflector section 10 along its axial direction. The oscillating motor 20 includes a stator 21 and a rotor magnet 22. The stator 21 is fixed to the retaining wall 113 by bolts or the like. An electromagnetic coil (not shown) and a fixing magnet are disposed on the stator 21. The rotor magnet 22 is a cylindrical two-pole magnet, and the main shaft 13 is inserted through the shaft hole 221 and fixed to the main shaft 13 by means of the magnet fixing member 23.

[0023] The rotor magnet 22 is a so-called inner rotor disposed inside the stator 21, which oscillates around a stationary position by energizing the electromagnetic coil. Here, oscillation refers to the periodic reciprocating motion of forward and reverse rotation within a specified angular range of less than 360°. When the energizing of the electromagnetic coil is disconnected, the rotor magnet 22 returns to its stationary position and comes to rest by the magnetic force of the fixing magnet. The dimensions of the rotor magnet 22 can be arbitrarily designed according to the constraints of the mounting, the required magnetic force, etc.

[0024] The encoder 30 is, for example, a reflective optical encoder, having a hub 31, a disk 32, and a sensing element 33, housed within a housing 35. The hub 31 is pressed and fixed to the main shaft 13. The disk 32 is mounted on the hub 31 and rotates integrally with the main shaft 13. Reflective and non-reflective patterns are formed on the disk 32 along the circumferential direction.

[0025] The detection element 33 is mounted on the substrate 34. The detection element 33 is an optical sensor that emits LED light and receives light reflected from the disk 32 corresponding to its rotation. The rotational position of the disk 32 is detected based on changes in the amount of received light. Thus, the encoder 30 can detect the oscillation position of the oscillating motor 20 and the reflector 18. The substrate 34 is fixed to the housing 35 by bolts (not shown). A through hole 341 is formed in the substrate 34 for the spindle 13 to pass through.

[0026] The outer casing 35 is formed as a bottomed cylindrical shape with an opening on the opposite side of the reflector section 10, and is fixed to the stator 21, for example, by a through bolt (not shown). A through hole 352 is formed at the bottom 351 for the main shaft 13 to pass through. The bottom 351 is located between the rotor magnet 22 and the hub 31. In this embodiment, the base 11, stator 21, and outer casing 35, which do not move even when the oscillating motor 20 is driven, are defined as the housing section 50.

[0027] In this embodiment, the spindle 13 is axially restricted by the E-ring 161 and the preload spring 165, and the preload spring 165 applies force in the opposite direction to the E-ring 161 (i.e., to the left of the paper). Here, if vibration or impact is applied to the oscillating actuator 5, the spindle 13 will move axially, and the reflector 18 will come into contact with the base 11, and the reflector 18 may be damaged.

[0028] When an impact is applied to the oscillating actuator 5, the movement of the main shaft 13 to the left of the paper plane is restricted by the E-ring 161. On the other hand, when subjected to an impact exceeding the load of the preload spring 165, the main shaft 13 may move to the right of the paper plane. To withstand a larger impact, although increasing the spring force of the preload spring 165 is also considered, the volume becomes larger in this case. Hereinafter, the direction of movement of the main shaft 13 under an impact exceeding the spring force of the preload spring 165 (i.e., to the right of the paper plane) will be defined as the "axis movement direction".

[0029] In this embodiment, a portion is provided where the gap between the component fixed to the main shaft 13 and the housing portion 50 is smaller than the gap C1 between the reflector 18 and the retaining wall 112 of the base 11 in the axial movement direction. Specifically, the gap C2 between the hub 31 and the bottom 351 of the housing 35 is smaller than the gap C1 between the reflector 18 and the retaining wall 112.

[0030] Therefore, when the main shaft 13 moves along the axial direction due to an impact that applies a load greater than the preload spring 165 to the oscillating actuator 5, the hub 31 abuts against the housing 35 before the reflector 18 abuts against the base 11, so the reflector 18 will not collide with the base 11, thus preventing damage to the reflector 18.

[0031] Furthermore, if the hub 31 comes into contact with the housing 35 due to movement of the spindle 13 caused by vibration, impact, etc., and the hub 31 is deformed or damaged, the positional relationship between the disk 32 and the detection element 33 will no longer be normal, resulting in a sensing abnormality. As a result, it is possible to detect that the oscillating actuator 5 has malfunctioned.

[0032] As described above, the ranging device 1 of this embodiment measures the distance to an object by scanning light to the outside and detecting the light reflected by the object, and includes a reflector 18, a base 11, a main shaft 13, a position holding part 16, and a hub 31.

[0033] The reflector 18 is driven to oscillate by the oscillating motor 20, thereby scanning light outward. The base 11 houses the reflector 18 internally. The main shaft 13 is fixed to the reflector 18 and is rotatably supported on the base 11 with at least one end protruding from it. The position holding part 16 has a preload spring 165 that applies force to the main shaft 13 axially to one side and an E-ring 161 that restricts the movement of the main shaft 13 in the direction of the applied force, maintaining the axial position of the main shaft 13. The hub 31 is fixed to the main shaft 13 on the outside of the base 11.

[0034] The fixed portion, including the base 11 and not driven by the swing motor 20, is designated as the housing portion 50. The distance between the end of the hub 31 on the side opposite to the direction of force application of the main shaft 13 and the housing portion 50 is less than the distance between the end of the reflector 18 on the side opposite to the direction of force application of the main shaft 13 and the base 11. Specifically, the gap C2 between the hub 31 and the bottom 351 of the housing 35 is less than the gap C1 between the reflector 18 and the retaining wall 112.

[0035] Therefore, when an impact exceeding the load of the preload spring 165 is applied to the oscillating actuator 5, the hub 31 abuts against the housing 35, thereby preventing the reflector 18 from colliding with the base 11. Thus, damage to the reflector 18 can be prevented. Furthermore, if a structure is provided inside the base 11 such that the reflector 18 abuts against the base 11 before the base 11, optical considerations such as high reflectivity need to be avoided. In this embodiment, the hub 31, as the abutting member, is provided on the outside of the base 11, thus suppressing optical considerations and constraints related to the abutting structure.

[0036] In the ranging device 1, a swing motor 20 and an encoder 30 capable of detecting the swing position of the reflector 18 are provided on the outside of the base 11. The encoder 30 has a disk 32 that is driven integrally with the main shaft 13, a disk hub 31 fixed to the main shaft 13 and on which the disk 32 is mounted, and a detection element 33 that detects the driving state of the disk 32. In detail, the detection part is the encoder, and the detection element 33 is an optical sensor that detects the light reflected by the disk 32.

[0037] In this embodiment, the abutting component is the hub 31. By employing a structure in which the hub 31 abuts against the housing 35 when an impact is applied to the oscillating actuator 5, abnormalities in the oscillating actuator 5 can be detected.

[0038] The position holding part 16 is provided on the outside of the base 11. In other words, the components related to the axial position holding of the spindle 13 are not provided inside the base 11. The position limiting part is an E-ring 161 provided on the opposite side of the preload spring 165, separated from the base 11. As a result, the axial positioning of the spindle 13 can be performed without affecting the scanning of light achieved by the reflector 18.

[0039] (Second Implementation) Figure 3 This describes the second embodiment. In this embodiment, the shape of the spindle 130 differs from that in the embodiment described above, and this will be the focus of the description. In this embodiment, the shaft portion 131 and the position limiting portion 132 of the spindle 130 are formed as a single unit. The position limiting portion 132 is provided protruding radially outward from the shaft portion 131 on the axially outer side of the bearing 14, and functions as an anti-disengagement component for the spindle 130. That is, in this embodiment, the preload spring 165 and the position limiting portion 132 constitute the position holding portion 16. Even with this configuration, it achieves the same effect as in the embodiment described above.

[0040] In the embodiment, spindles 13 and 130 correspond to "swing shafts", E-ring 161 and position limiting part 132 correspond to "position limiting part", preload spring 165 corresponds to "force application part", encoder 30 corresponds to "detection part", disc hub 31 corresponds to "abutment part" and "holding part", and disc 32 corresponds to "detected part".

[0041] (Other implementation methods) In the above embodiment, the gap C2 between the hub 31 and the bottom 351 of the housing 35 is smaller than the gap C1 between the reflector 18 and the retaining wall 112. In other embodiments, the abutment member may also be a component other than the hub. That is, a portion may be provided where the gap between the end of the component other than the hub on the axial movement direction side and the housing is smaller than the gap C1. Furthermore, when the abutment member is provided inside the base, optical considerations such as not hindering the reflection of the reflector are required; therefore, the abutment member is preferably provided outside the base.

[0042] In the above embodiments, the detection element is an optical sensor. In other embodiments, components other than optical sensors (such as magnetic sensors) may be used to detect the driving state of the swing shaft, and components other than encoders may be used as the detection unit. Furthermore, in other embodiments, the actuator and reflector can be used as long as they can cause the reflector to swing, and their structure and configuration may differ from the above embodiments. This disclosure is not limited to the above embodiments, and various implementations are possible without departing from its spirit.

[0043] This disclosure is described based on embodiments. However, this disclosure is not limited to these embodiments and structures. This disclosure also includes various modifications and modifications within the same range. In addition, various combinations and forms, as well as other combinations and forms containing only one element, more than one element, or less than one element, are also included within the scope and spirit of this disclosure.

Claims

1. A ranging device that measures the distance to an object by scanning light outward and detecting light reflected by the object, characterized in that, have: The reflector (18) is driven by the oscillation of the actuator (20) to scan light to the outside; The base (11) has the reflector disposed inside it; The swing shaft (13, 130) is fixed with the reflector and is supported on the base in a swingable manner with at least one end protruding from the base; The position holding part has a force applying member (165) and a position limiting part (161, 132) to maintain the axial position of the swing shaft. The force applying member applies force to one side of the swing shaft in the axial direction, and the position limiting part restricts the movement of the swing shaft in the direction of the applied force. as well as The abutment member (31) is fixed to the swing shaft on the outside of the base. The fixed portion, which includes the base and is not driven by the actuator, is designated as the housing portion (50). The distance between the end of the abutting member on the side opposite to the direction of force application of the swing axis and the housing part is less than the distance between the end of the reflector on the side opposite to the direction of force application of the swing axis and the base.

2. The ranging device according to claim 1, characterized in that, On the outer side of the base, the actuator and a detection unit (30) capable of detecting the swing position of the reflector are provided. The detection unit includes a detection part (32) that is driven integrally with the swing shaft, a holding member (31) that is fixed to the swing shaft and on which the detection part is mounted, and a detection element (33) that detects the driving state of the detection part. The abutting component is the retaining component.

3. The ranging device according to claim 2, characterized in that, The detection unit is an encoder. The detection element is an optical sensor that detects light reflected by the detected part.

4. The ranging device according to any one of claims 1 to 3, characterized in that, The position holding part is disposed on the outside of the base. The position limiting part is an E-shaped ring disposed on the opposite side of the force-applying component, separated from the base.

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