Encoder and method of manufacturing the same

Abstract

Provided is an encoder that can be manufactured at low cost with fewer steps, and a manufacturing method therefor. The rotary encoder includes a rotary slit plate that can rotate about an axis, a printed board for measuring a rotational displacement of the rotary slit plate, a flange for fixing the printed board after the printed board is positioned, a first connector fixed to the flange, and a second connector mounted to the printed board and connected to the first connector, at least one of the first connector and the second connector being a floating connector having a configuration that can absorb displacement in a direction perpendicular to the axis.

Description

[0001] Technology Area

[0002] This invention relates to an encoder and its manufacturing method. Background Technology

[0003] Conventionally, as components used to measure the rotational angular position, rotational speed, or displacement and displacement speed of a linear motion shaft driven by a motor, rotary encoders connected to the rotating shaft of the motor and linear encoders connected to the linear motion shaft are known (see, for example, Japanese Patent Application Publication No. 2018-113771). Furthermore, to improve the assemblability of the encoder and adjust the relative positions between assembled components, it is also known to use elastic components such as springs as one of the constituent elements (see, for example, Japanese Patent Application Publication Nos. 09-269242 and 10-227661).

[0004] On the other hand, it is known to use floating connectors in electronic device modules that absorb positional offsets when the connectors are mated together (see, for example, Japanese Patent Application Publication No. 2018-125095).

[0005] Conventional encoders have movable parts such as a rotating slit plate and a sensor unit for measuring the displacement of these movable parts. However, in order to obtain accurate signals related to the rotational position of the motor, optical position adjustment between the movable part and the sensor unit is required. Conventionally, after this position adjustment, the sensor unit was fixed by soldering, but this increases the number of manufacturing steps (lengthening the manufacturing line).

[0006] On the other hand, a connector could be used to fix the sensor unit, eliminating the need for soldering. However, in this case, the connector would need to be flexible, such as by making it from a soft material, to allow for optical position adjustment. This, however, would result in a decrease in the strength of the connector. Summary of the Invention

[0007] The problem the invention aims to solve

[0008] Therefore, the goal is to find a technology that guarantees the strength of the encoder and manufactures it at a low cost with fewer steps.

[0009] Solution for solving the problem

[0010] One technical solution disclosed herein is a rotary encoder having: a movable part; a sensor part for measuring the position of the movable part; a flange; a first connector fixed to the flange; and a second connector mounted on the sensor part and connected to the first connector, wherein at least one of the first connector and the second connector is a floating connector.

[0011] Alternatively, the encoder described above may have a position adjustment area, which serves as a holding part that can be mechanically held during assembly, and this position adjustment area includes a planar portion.

[0012] For the encoder described above, the position adjustment area may also have a concave or convex portion.

[0013] Alternatively, the encoder described above may have multiple floating connectors configured such that each floating connector can absorb a different primary displacement direction from the others.

[0014] Alternatively, one of the first connector and the second connector may be a floating connector, and the other of the first connector and the second connector may be a rigid connector.

[0015] Another technical solution disclosed herein is a method for manufacturing a rotary encoder, the rotary encoder having a movable part, a sensor part for measuring the position of the movable part, and a flange, the method for manufacturing the rotary encoder comprising: fixing a first connector to the flange; mounting a second connector to the sensor part; connecting the second connector to the first connector; and fixing the sensor part to the flange, wherein at least one of the first connector and the second connector is a floating connector.

[0016] The effects of the invention

[0017] This invention enables the manufacture of encoders with fewer steps and lower cost. Attached Figure Description

[0018] The objects, features, and advantages of the present invention can be more clearly understood through the following description of embodiments in association with the accompanying drawings. In these drawings,

[0019] Figure 1 This is a perspective view showing a structural example of a rotary encoder according to a preferred embodiment.

[0020] Figure 2 This is a top view showing an example of the shape of a printing plate.

[0021] Figure 3 This is a top view showing another example of the shape of a printing plate. Detailed Implementation

[0022] Figure 1This is a perspective view showing a structural example of a rotary encoder as a preferred embodiment. The rotary encoder 10 includes: a movable part (here, a rotating slit plate (plate) capable of rotating about axis 12) 14; a sensor part (here, a printed circuit board (substrate) provided with a light-emitting element and a light-receiving element, etc.) 16 for measuring the rotational displacement (position) of the rotating slit plate 14; a flange 18 for fixing the printed circuit board 16 after it is positioned (described later); a first connector 20 fixed to the flange 18; and a second connector 22 mounted on the printed circuit board 16 and connected to the first connector 20. At least one of the first connector 20 and the second connector 22 (here, the second connector 22) is a floating connector that includes a structure capable of absorbing displacement in at least a direction perpendicular to axis 12.

[0023] The flange 18 is mounted on the housing of a servo motor or other electric motor (rotary motor) 24, which is schematically shown. The rotating slit plate 14 is connected to the rotating shaft 26 of the motor 24. Furthermore, a slit (not shown) is formed in the rotating slit plate 14 that can be detected by a detection unit (not shown) disposed on the printed circuit board 16. Therefore, if the rotating slit plate 14 rotates with the rotation of the rotating shaft 26, the detection unit detects the slit of the rotating slit plate 14 and outputs a detection signal. Based on this detection signal, the rotational angle position and rotational speed of the rotating shaft 26 can be detected. The basic function of such a rotary encoder 10 is the same as that of the prior art, so detailed description is omitted. A cover (not shown) for protecting the printed circuit board 16 from external influences can be installed on the side of the flange 18 opposite to the side mounted on the motor 24 (the lower side in the example).

[0024] The floating connector (here, the second connector) 22 is connected to the first connector 20 in a manner that allows it to be displaced relative to the first connector 20. The floating connector 22 can be configured to be displaced in any direction, and the printed circuit board 16 can be displaced relative to the flange 18 in a predetermined direction set according to the floating connector 22. However, in order to smoothly perform the optical micro-adjustments described later, with the direction of the axis 12 as the Z direction, the floating connector 22 is preferably able to absorb displacement at least in any direction along the XY plane.

[0025] In addition, the floating connector 22 electrically connects the electronic components (not shown) such as the detection unit mounted on the printed circuit board 16 to the calculation and processing device (not shown) that calculates the rotation angle position and rotation speed of the rotating shaft 26 based on the detection signals mentioned above.

[0026] In this embodiment, the floating connector 22 can be a known floating connector. By using the floating connector 22 for the connection between the flange 18 of the rotary encoder 10 and the printed circuit board 16, the previously required soldering process can be omitted in the manufacturing process of the rotary encoder. Therefore, the overall length of the rotary encoder manufacturing line can be shortened compared to the past, and manufacturing time and costs can be reduced.

[0027] Furthermore, since the floating connector itself has the function of absorbing displacement, it is not necessary to make the connector flexible by making the connector that engages with the floating connector (the first connector 20 in this embodiment) made of a soft material. Therefore, the first connector 20 can be a rigid connector (e.g., made of only rigid materials). Rigid connectors are generally low-cost and high-strength, so by using rigid connectors, a rotary encoder with high reliability can be constructed.

[0028] Here, the positioning and fixing of the printed circuit board 16 in the manufacturing process (manufacturing method) of the rotary encoder 10 will be described. First, a robot (described later) is used... Figure 2 and Figure 3 The illustration only schematically depicts industrial machinery such as a robotic arm 32 holding the printed circuit board 16 and moving a robot to engage the first connector 20 with the second connector 22. In this embodiment, the second connector 22 is a floating connector, therefore high positioning accuracy is not required for the robot at this stage.

[0029] Next, optical position adjustment (fine-tuning) is performed between the printing plate 16 and the rotating slit plate 14. After the fine-tuning is complete, the printing plate 16 is secured to the flange 18 using other means such as robots or threaded fastening devices. For example, a bolt (not shown) is inserted into the hole 28 formed in the printing plate 16, and the bolt is threaded into the threaded hole formed in the flange 18 (the raised portion 30 on the flange 18 in the example), thereby securing the finely adjusted printing plate 16 to the flange 18. Preferably, the inner diameter of the hole 28 in the printing plate 16 is larger than the bolt diameter by a certain amount to absorb the fine-tuning amount. In this way, the positioning and fixing of the printing plate 16 can be performed automatically using robots, bolted fastening devices, etc., but at least a portion of the above manufacturing process can also be performed manually by an operator.

[0030] In this embodiment, during the positioning and fixing process of the printed circuit board 16 as described above, the difficulty of fine-tuning (optical position adjustment) of the printed circuit board 16 increases due to the displacement function of the floating connector 22. Therefore, as will be described later, by making the printed circuit board 16 not a simple disc shape, its position can be easily adjusted.

[0031] Figure 2 This diagram shows a top view of the printed circuit board 16 and a robotic arm 32 (only a portion is shown schematically) capable of holding the printed circuit board 16. The printed circuit board 16 has a position adjustment region 34, which is formed by cutting off a portion that is approximately circular in top view along a straight line as a holding part that can be held by assembly machinery such as the robotic arm 32. That is, the position adjustment region 34 corresponds to the radially outer end face of the printed circuit board 16 in the direction based on the axis 12, and includes a flat portion 36. In addition, it is preferable to provide multiple position adjustment regions 34 (flat portions 36), and in particular, it is preferable to form them in a rotationally symmetrical position with respect to the axis 12. As a result, the printed circuit board 16 can be accurately held by a gripping robotic arm 32, for example, including a flat portion 38. Furthermore, by providing the flat portion 36, it is not limited to the use of a robotic arm, making positioning and gripping using various gripping devices easier, and making a significant contribution to the automation of the manufacturing process of rotary encoders.

[0032] Alternatively, the printing plate 16 may have a recess 40, such as a notch, in a portion of the position adjustment area 34 to prevent the printing plate 16 from shifting relative to the robot 32 in the planar direction of the flat portion 36 when held by the robot 32, etc. (resulting in so-called holding misalignment). In this case, the robot 32 is provided with a protrusion 42 that can engage with the recess 40 (more specifically, has a shape that matches the recess 40), thereby also preventing the aforementioned planar direction ( Figure 1 Y direction in, Figure 2 The position offset in the vertical direction.

[0033] Figure 3 This is another example of the construction of the printing plate 16. Figure 3 Examples and Figure 2 Compared to the previous example, the difference lies in the following aspects: the position adjustment area 34 of the printed circuit board 16 has a protrusion 44, while the robotic arm 32 has a groove (notch) 46 that can engage with the protrusion 44 (more specifically, has a shape that matches the protrusion 44); the other parts are the same. Therefore, in Figure 3 In this example, the robotic arm 32 is also able to hold the printing plate 16 without any positional shift. In this way, a portion of the radial end face of the printing plate 16 is made flat, and a recess or protrusion is provided on that end face. On the other hand, a portion of the robotic arm side is made flat, and a protrusion or groove with a shape matching the aforementioned recess or protrusion is formed. This allows for precise holding of the printing plate 16 without any positional shift, and also enables precise fine adjustments as described above.

[0034] In this disclosure, the floating connector can be a single unit, but as follows: Figure 1As shown, multiple floating connectors (two in the example) can also be provided. In this case, the multiple floating connectors are preferably configured such that the main displacement directions that each floating connector can absorb are different from each other. For example, when using floating connectors whose main displacement direction is only the X direction, if two floating connectors are arranged in the same orientation at a position 180 degrees apart from each other relative to axis 12, the printed circuit board 16 can be easily displaced in the X direction, but it is difficult to displace in the Y direction. Therefore, if as shown... Figure 1 As shown, by configuring two floating connectors with different orientations, the desired displacement can be obtained for either the X or Y direction.

[0035] As described above, in this disclosure, a floating connector is applied to the encoder, thereby achieving unique effects that are not present when applied to other electronic devices. Furthermore, by forming a position adjustment region 34 in the holding portion of the sensor section (printed board 16), high-precision gripping and positioning using automated assembly machinery such as robots is possible, thus facilitating the automation of the encoder manufacturing process, including subsequent thread tightening (fixing of the printed board 16). The encoder of this disclosure can be applied to either incremental encoders or absolute encoders.

[0036] Furthermore, the encoder disclosed herein can be applied to a wide variety of rotating bodies, such as rotary motors, and in particular, it can be appropriately applied to servo motors that drive the axes of robots, or motors that drive the spindles and feed axes of machine tools.

[0037] In the above embodiments, an optical rotary encoder was described, but the present invention is not limited thereto. The characteristic structure described above can also be applied to various encoders such as magnetic rotary encoders, optical linear encoders, and magnetic linear encoders. Furthermore, for example, in the case of an optical linear encoder, the movable part can be equivalent to a linear scale; in the case of a magnetic rotary encoder or a magnetic linear encoder, the movable part can be equivalent to a magnetic ring or a magnetic scale, respectively, and the sensor part can be equivalent to a magnetic sensor or a printed circuit board on which the magnetic sensor is mounted.

[0038] By employing this disclosure, the use of a floating connector eliminates the need for soldering the sensor section, thereby improving encoder productivity. Furthermore, the use of a rigid connector allows for increased encoder strength.

Claims

1. An encoder characterized by comprising: a movable portion; a sensor portion for measuring a position of the movable portion; a flange; a first connector fixed to the flange; and a second connector mounted to the sensor portion and connected to the first connector, at least one of the first connector and the second connector is a floating connector that electrically connects an electronic component mounted to the sensor portion and an arithmetic processing device, the encoder has a plurality of the floating connectors, and the plurality of the floating connectors are arranged such that a main displacement direction that each of the floating connectors can absorb is different from each other.

2. The encoder according to claim 1, characterized by comprising: the sensor portion has a position adjustment region that is a held portion capable of being held by an assembly machine, and the position adjustment region includes a flat portion.

3. The encoder according to claim 2, characterized by comprising: the position adjustment region has a recessed portion or a protruding portion.

4. The encoder according to any one of claims 1 to 3, characterized by comprising: one of the first connector and the second connector is the floating connector, and the other of the first connector and the second connector is a rigid connector.

5. A manufacturing method of an encoder that has a movable portion, a sensor portion for measuring a position of the movable portion, and a flange, characterized by comprising: fixing a first connector to the flange; mounting a second connector to the sensor portion; connecting the second connector to the first connector; and fixing the sensor portion to the flange, at least one of the first connector and the second connector is a floating connector that electrically connects an electronic component mounted to the sensor portion and an arithmetic processing device, the encoder has a plurality of the floating connectors, and the plurality of the floating connectors are arranged such that a main displacement direction that each of the floating connectors can absorb is different from each other. ​ ​

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