CN104613997B - Encoder - Google Patents

Abstract

The utility model discloses an encoder, and the encoder comprises a disc; a rail with a plurality of reflection parts which are arranged on the disc along the measurement direction; a light source which is used for emitting light to the reflection parts; a light-receiving array for receiving the light which is emitted by the light source and reflected on the rail; and a hub which is disposed at a side, opposite to the light source, of the disc. Moreover, the hub is provided with a tapered part which is disposed at at least the position on the light axis of the light source and inclined relative to the light axis of the light source.

Description

Encoder

Cross-Reference to Related Applications

The present invention is included in Japanese Priority Patent Application JP2013- submitted to Japan Office on November 5th, 2013 The theme of the content correlation disclosed in 229835, the full content of the Japanese Priority Patent Application is merged in by reference To herein.

Technical field

Embodiments disclosed herein is related to a kind of encoder.

Background technology

JP2013-130394A (page 7, Fig. 2) is disclosed and is arranged oil seal part between disk and framework to suppress axle The encoder that the grease of the atomization held is revealed to encoder.The oil seal part by black the light absorbing material such as rubber or resin Matter is made, and is coated in black or is coated with easy light absorbing color or pattern.

When the light projected from light source as scattered light or veiling glare not as anti-in being comprised in by optical signal When penetrating light and being received by photo detector, noise is produced.Such noise is the reason for declining the position detection accuracy of encoder.

In above-mentioned prior art, oil seal part is made up of light absorbing material, or is coated in easily absorption The design and color of light, thus suppresses the scattering or reflection of light.However, some parts may not be by light absorbing material structure Into, or the coating of the light for not being amenable to absorb irradiated.When this part is configured between disk and framework, encoder Accuracy of detection be possible to decline.

The content of the invention

One aspect of the present invention is summarized as a kind of encoder, including：Disk；The circle is configured in along measurement direction Multiple reflecting parts on disk；It is configured to project the light source of light to the reflecting part；It is configured to receive and is projected by the light source And the photo detector of the light in reflecting part reflection；And the light source being configured on the disk opposition side and With on the position on the optical axis of at least described light source relative to the light source inclined light shaft part part.

Another aspect of the present invention is summarized as a kind of encoder, including：Disk；The circle is configured in along measurement direction Multiple reflecting parts on disk；It is configured to project the light source of light to the reflecting part；It is configured to receive and is projected by the light source And the photo detector of the light reflected on the reflecting part；And the side of the light by projecting from the light source and through the disk To the device in the direction for changing into the inclined light shaft relative to the light source.

Description of the drawings

Fig. 1 is the explanatory diagram that the servo-drive system to being provided with the encoder according to embodiment is illustrated；

Fig. 2 is the explanatory diagram to being illustrated according to the encoder of embodiment；

Fig. 3 is the explanatory diagram that the hub to arranging in the encoder according to embodiment is illustrated；

Fig. 4 is the explanatory diagram to being illustrated according to the encoder of the first modified example；

Fig. 5 is the explanatory diagram that the hub to arranging in the encoder according to the first modified example is illustrated；

Fig. 6 is the explanatory diagram to being illustrated according to the encoder of the second modified example；And

Fig. 7 is the explanatory diagram that the hub to arranging in the encoder according to the second modified example is illustrated.

Specific embodiment

Hereinafter, referring to the drawings, embodiment is illustrated.

Servo-drive systems ＞ of ＜ 1.

First, the structure for being provided with the servo-drive system of the encoder according to present embodiment will be illustrated with reference to Fig. 1.

As shown in figure 1, servo-drive system S includes servomotor SM and control device CT.Servomotor SM includes encoder 100 With motor M.

Motor M is of power generating source not including encoder 100.Motor M is rotor (not shown) relative to fixed The rotary-type motor of sub- (not shown) rotation, it exports rotation by making the axle SH for being fixed to rotor rotate around axle center AX Power.

In addition, single motor M can be referred to as servomotor, but, in the present embodiment, will be including the He of encoder 100 The structure of motor M is referred to as servomotor SM.Motor M is not specially limited, for example, as long as its position data can be by coding Device 100 is detected.In addition, motor M is not limited to use electricity as the electrodynamic machine of power source, it can also be for example Hydraulic type motor, pneumatic type motor or steam-type motor etc. use the motor of other power sources.But, for convenience of description, The situation that motor M is electrodynamic machine is illustrated below.

Encoder 100 is connected to the opposition side of the revolving force outlet side of the axle SH of motor M, but, it is not necessarily limited to the phase Toss about.Encoder 100 can also be connected to the outlet side of the revolving force of axle SH.Encoder 100 is by detection axle SH (rotor) Position exports the position data of the position for representing motor M detecting the position (the also referred to as anglec of rotation) of motor M.

Encoder 100 can except detection motor M position in addition to or replace detection motor M position, also detect motor M Speed (also referred to as rotary speed, angular speed etc.) and motor M acceleration (also referred to as rotary acceleration, angular acceleration etc.) At least one of.In such a case, it is possible to for example, by obtaining first differential or second-order differential of the position relative to the time Or predetermined time period detection signal (for example, following increment signal) is counted speed to detect motor M and Acceleration.For convenience of description, below, the physical quantity detected by encoder 100 is described as into position.

Controller CT obtains the position data from the output of encoder 100, and according to acquired position data controlling electricity The rotation of machine M.Therefore, using electrodynamic machine, used as in the present embodiment of motor M, controller CT is according to position data control System puts on the curtage of motor M, so as to the rotation of controlled motor M.In addition, controller CT can also be by from upper control Device (not shown) processed obtains upper control signal, to realize the position represented by the upper control signal from axle SH outputs Deng revolving force, carry out controlled motor M.Additionally, being that hydraulic type, pneumatic type, steam-type etc. use other power sources in motor M In the case of, controller CT can be by controlling supplying come the rotation of controlled motor M from these power sources.

The encoder ＞ of ＜ 2.

Next, illustrating to the structure of the encoder 100 according to present embodiment with reference to Fig. 2.According to this embodiment party The encoder 100 of formula is configured to be provided with so-called " complete type " encoder of the special framework 10 of encoder or axle sh.At this In the case of kind, the axle sh of encoder connects via not shown hookup with the axle SH of motor in the way of with same axle center Connect.But, encoder 100 is not limited to " complete type ", and can be configured to disk 110 and be connected with the axle SH of motor and do not use So-called " embedded type " encoder of the axle sh of encoder.In this case, framework 10 is configured to the framework of motor M. Below, for convenience of description, the situation that the encoder of complete type is configured to encoder 100 is illustrated.

Here, the structure of encoder 100 for convenience of description, is defined as below and is suitably used above-below direction.In Fig. 2 In, by disk 110 towards optical module 130 direction, i.e. along Z axis positive direction be referred to as " on ", will be referred to as along the negative direction of Z axis D score.But, the direction changes according to the mounting means of encoder 100, and therefore does not limit each part of encoder 100 Position relationship.

As shown in Fig. 2 including framework 10, housing 150, substrate 16, optical module according to the encoder 100 of present embodiment 130th, hub 160, disk 110, position data generating unit 140 and encoder cover 101.

(2-1. disks)

Disk 110 is fixed to the disk fixed part 162 of following hubs 160.Disk 110 is formed as discoideus, bolt 14 Through the substantially central portion of disk, and the through hole 111 for coordinating with the bolt fastening part 163 of hub 160 is provided with central authorities.Circle The lower surface 110B of disk 110 is fixed to disk stationary plane in the state of bolt fastening part 163 is coupled in through hole 111 162A, disk stationary plane 162A are the upper surfaces of disk fixed part 162.Then, disk 110 with axle sh having same axle center Mode is connected via hub 160 with axle sh.Axle sh is rotatably supported by bearing 20 by framework 10.The rotation that disk 110 passes through motor M Turn, i.e. the rotation of axle sh is rotated.

Track SA is formed with the upper surface 110A of disk 110.Track SA is formed in the upper surface of disk 110 The circular track being configured on 110A centered on disc centre.Track SA has along measurement side on the complete cycle of track To the multiple reflecting part (not shown) for arranging.Here, " measurement direction " is measured optically by following optical modules 130 The measurement direction during track formed on disk 110.In the measured pair as in the present embodiment rotation for liking disk 110 In type encoder, measurement direction is consistent with the circumferencial direction of disk 110.Each reflecting part is configured to reflection from following optical modes The light that the light source 131 of block 130 is projected.That is, encoder 100 is that the light projected from light source 131 is reflected and by following by reflecting part So-called " reflection-type " encoder that photo detector is received.Multiple reflecting parts are in a circumferential direction for example having increment pattern Mode is configured in the complete cycle of disk 110.Reflecting part can be referred to as " slit (reflectance slit) ", this is because reflecting at reflecting part Light along predetermined direction advance and do not stop light path.Additionally, multiple reflecting parts can be on the whole grating.

Disk 110 is formed by the material through light.In the present embodiment, disk 110 is for example formed by glass.Glass with Metal (for example, stainless steel) is compared, and thermal conductivity is little.Therefore, when disk 110 is formed by glass, the axle in motor M can be suppressed The heat produced on sh is transmitted from hub 160 to disk 110.Also, the reflecting part of track SA can be in the upper table of the disk 110 of glass system On the 110A of face for example, by reflected light material (for example, aluminium) vapour deposition being formed.But, the forming method of reflecting part is not It is limited to the example.

(2-2. optical modules)

Optical module 130 is formed as in this embodiment substrate shape, and with a part of facing with the track SA of disk 110 Mode, be fixed on the lower surface of substrate 16 parallel to disk 110.Therefore, as disk 110 rotates, the energy of optical module 130 Enough relative to track SA relative movements in a circumferential direction.Optical module 130 and disk 110 in the face of side surface, i.e. under On surface, light source 131 is provided with and by optical arrays PA.

Light source 131 is configured to project light to by a part of the track SA of relative position.Light source 131 is not especially Limit, as long as it is can be to the light source of irradiation area illumination light.It is, for example possible to use light emitting diode (LED).Light source 131 are especially configured without being configured with the spot light of optical lens etc., and project diffusion light from illuminating part.Additionally, work as carrying And when " spot light ", light source needs not be strict point.Light can be sent from limited light face of penetrating, if light source be considered as from The light source of diffusion light can be sent in the angle and operation principle of design from the position of substantially point-like.In addition, " diffusion light " The light projected towards all directions from spot light is not limited to, and including injection while diffusion towards limited certain orientation Light.That is, " diffusion light " described herein includes thering is bigger diffusible light than directional light.Use as described above Spot light, light source 131 can be to the substantially uniformly irradiation lights of the track SA by relative position.In addition, by using as above Described spot light, because light need not be assembled and be spread by optical element, therefore, it is difficult to producing the mistake caused by optical element Difference etc. such that it is able to improve rectilinear propagation of the light towards track.

Configured along around light source 131 by optical arrays PA, and be configured to receive the reflection in relative track SA The light reflected in portion.Included multiple photo detector (not shown) by optical arrays PA.As each photo detector, it is, for example possible to use Photodiode (PD).But, photo detector is not limited to PD.That is, for photo detector, as long as it can be received from light source 131 The light for being received simultaneously is converted into electric signal by the light that sends, then be not specially limited.The electric signal quilt generated in photo detector Export to position data generating section 140.

(2-3. hubs)

Hub 160 will be illustrated with reference to Fig. 2 and Fig. 3.Hub 160 is the company for disk 110 and axle sh to be connected to each other Relay part, and it is configured in the opposition side of the light source 131 of disk 110.Hub 160 has disk fixed part 162, bolt fastening part 163rd, main part 164 and bearing cap 165.In the present embodiment, hub 160 is for example by brass or stainless steel and other metal materials Formed, but, if material has higher rigidity, it is not limited to metal.

Bolt fastening part 163 is formed in the substantially central portion of disk fixed part 162 with the shape for projecting upwards.Bolt is fastened Portion 163 in the way of making disk 110 and hub 160 that there is same axle center, in being coupled to the through hole 111 of disk 110.In bolt fastening The inner side in portion 163 is provided with through hole 161, and bolt 14 is extended through in through hole 161.Vertically disk 110 is run through in direction to bolt 14 The through hole 161 of through hole 111 and hub 160, and be screwed in the bolt hole 13 being arranged in axle sh.Thus, hub 160 is fixed to axle The upper end of sh, while the disk 110 for being fixed to the disk fixed part 162 of hub 160 is connected with axle sh.

Disk fixed part 162 can include disk stationary plane 162A and isometrical portion 162B, and disk 110 is fixed to disk and consolidates Determine face 162A.Isometrical portion 162B may be located between disk stationary plane 162A and following tapering 164A so that apart from disk The distance on axis direction (Z-direction) of stationary plane 162A is that radical length is equal in the range of preset distance.That is, disk Fixed part 162 is formed as being formed centrally within the cylindric of through hole 161, and its upper surface is disk stationary plane 162A, and main part is Isometrical portion 162B.The lower surface 110B of disk 110 is abutted with disk stationary plane 162A, and disk stationary plane 162A is glued by appropriate Knot agent is fixed to lower surface 110B.

Main part 164 be formed as with away from disk 110 centered on the axle center AX of axle sh radical length increase it is big Cause truncated cone shape.Tapering 164A is provided with the outer peripheral face of main body.Hub 160 is configured to tapering 164A and is located at least in light source On 131 optical axis h, tapering 164A is inclined relative to optical axis h and is caused reflected light towards radial outside.In addition, mentioned herein " incline Oblique cone degree " is neither the taper parallel with optical axis h is nor the taper vertical with optical axis h.That is, " inclination taper " refer to relative to Optical axis h has the taper in the state of constant angle of inclination (but, not including 90 degree) with tolerance.

Bearing cap 165 is located at the bottom of main part 164 (tapering 164A).Bearing cap 165 can have than rotatably supporting The bigger external diameter of the external diameter of the bearing 20 of axle sh.Therefore, the bearing cap can be configured to cover the side of disk 110 of bearing 20 Whole surface.By this structure, bearing cap 165 can reduce the bearing being atomized because the rotation of axle sh causes temperature to rise Leakage of 20 grease to the side of encoder 100.In addition, can form concave on the face towards bearing 20 of bearing cap 165 Oil groove 166.

Tapering 164A equivalent to one of the inclined parts of optical axis h relative to light source 131 being located at least on optical axis h, One equivalent to the part for being provided with the part of hub 160.In addition, hub 160 is equivalent to in the optical axis h relative to light source 131 One of device of the light that projects and through disk 110 is received from light source 131 on inclined face.

(2-4. substrates and housing)

Substrate 16 is, for example, discoideus printed wiring board, and in the lower surface of substrate optical module 130 and many is provided with Individual component.Substrate 16 is formed with the diameter roughly the same with housing 150, and the edge part of substrate 16 is positioned in shell On the face 151 of body 150.It is fixed along the circumferential direction with impartial multiple through hole 16A that are arranged at intervals with the edge part of substrate 16 Screw 15 is penetrated in multiple through hole 16A.Housing 150 for example formed as cylindrical shape, and be configured to supporting substrates 16 and Accommodate disk 110, optical module 130 and the hub 160 of encoder 100.Housing 150 has multiple through holes 152, fixing screws 15 penetrate in multiple through holes 152.The through hole of fixing screws 15 vertically the through hole 16A of direction through substrate 16 and housing 150 152, and be screwed in the screw hole being arranged in framework 10.Thus, substrate 16 and housing 150 are fixed to framework 10.

In addition, housing 150 includes the tapering 164A pleurapophysis to hub 160 on the part on the lower of ratio disk 110 of inner peripheral surface The protuberance 153 for going out.Protuberance 153 is arranged on the whole inner peripheral surface on the circumferencial direction of housing 150.

Housing 150 can be by the color (below, that more light are absorbed compared with the color of the part in addition to housing 150 One light absorbing colours) constitute, or the inner side of housing can be coated in the first light absorbing colours.Part in addition to housing 150 can Being surface, surface of substrate 16 of disk 110 etc..First light absorbing colours can be the part beyond luminance factor housing 150 Color the low color of reflectivity.For example, when light source 131 projects white light and disk 10 is made up of glass, glass surface Reflectivity be about 3%.As a result, the first light absorbing colours can be color (for example, black) of the reflectivity less than 3%.Separately Outward, because reflectivity changes according to the wavelength of the light projected by light source 131, therefore first can be selected according to light source 131 Light absorbing colours.It is preferred that taking the countermeasure that the surface at least exposed in disk 110 of framework 10 is applied as the first light absorbing colours.

The operation ＞ of the encoders of ＜ 3.

One of the action of encoder 100 is illustrated.By supplying external power source to motor M, when axle sh rotates simultaneously And disk 110 is when rotating, from light source 131 pairs by the track SA irradiation lights of relative position, by optical arrays PA receptions in track The light of SA reflections.Then, electric signal is generated and by the signal output for being generated to position data by the photo detector of optical arrays PA Generating unit 140, position data generating unit 140 generates the positional number of the position in 1 turn that represents disk 110 based on input signal According to, and position data is continuously exported to controller CT.

Effects ＞ of the ＜ 4. according to embodiment

As described above, the encoder 100 of present embodiment includes being configured in the hub of disk 110, light source 131 opposition side 160.Hub 160 includes tapering 164A inclined relative to optical axis h on the position on the optical axis h of at least light source 131.Accordingly, it is capable to It is enough receive from light source 131 on the tapering 164A of hub 160 project and through disk 110 light (especially, through each of track SA Light between reflecting part), and the reflected light on the direction that light is not received by optical arrays PA.As a result, can reduce in light Receive on array PA and cause the scattered light of noise or the situation of veiling glare, thus improve the accuracy of detection of encoder 100, scattered light Or veiling glare is beyond the reflected light (in the reflected light of reflecting part reflection) that will be included in by optical arrays PA by optical signal Light.

In the present embodiment, especially, the hub 160 disk 110 and axle sh being connected to each other has tapering 164A.As above Described, hub 160 is formed to have rigidity by having glossiness metal material (stainless steel, brass etc.).Therefore, if hub 160 With the face on the optical axis h with optical axis perpendicular, then project from light source 131 and through disk 110 light on hub 160 quilt Reflect and by being received on optical arrays PA, this is the reason for causing noise.In the present embodiment, hub 160 is in outer peripheral face At least optical axis h on position on have tapering 164A, therefore, it is possible to make light to radial outside reflect.Therefore, even if working as hub 160 Formed by the larger metal material of reflection light quantity, it is also possible to which reduction causes the scattered light or veiling glare of noise by optical arrays PA Situation about being received.

In addition, in the present embodiment, especially, hub 160 has disk stationary plane 162A and positioned at disk stationary plane Isometrical portion 162B between 162A and tapering 164A.Thereby, it is possible to obtain following effect.That is, in the system of reflective encoder In making operation, by the disk stationary plane for cutting hub 160 before disk 110 to be attached to the disk stationary plane 162A of hub 160 Thus 162A makes light source 131 and by between optical arrays PA and disk 110 adjusting the length of axis direction (Z-direction) Gap has precision.Now, in the present embodiment, because hub 160 has isometrical portion 162B, the link of disk stationary plane 162A Area can become stable, without being changed due to machining.Therefore, it is possible to suppress between hub 160 and disk 110 The fluctuation of binding strength, and the reliability of encoder 100 can be improved.Further, since hub 160 has isometrical portion 162B, therefore The distance between light source 131 and tapering 164A can be increased.Therefore, can be reduced by the decay of light and be reflected on the 164A of tapering Light quantity, and can further improve the reduction effect of scattered light or veiling glare.

In addition, in the present embodiment, especially, hub 160 has the table of the side of disk 110 for being configured to cover bearing 20 The bearing cap 165 in face.Thereby, it is possible to obtain following effect.I.e., generally, when the temperature of encoder 100 is due to the rotation of axle sh And when raising, the grease of bearing 20 is atomized and splashes.When the grease of atomization goes out to the side leakage of encoder 100, grease is attached to light Source 131 or by the opticses such as optical arrays PA or disk 110, from light source 131 to being possible to reduce by the light quantity of optical arrays PA, leads to The reliability for crossing the testing result of encoder 100 is possible to decline.In the present embodiment, hub 160 has and is configured to cover The bearing cap 165 on the surface of the side of disk 110 of bearing 20.Therefore, it is possible to suppress due to axle sh rotation produce heating and mist Leakage of the grease of the bearing 20 of change to the side of encoder 100.Therefore, it is possible to improve the reliability of encoder 100.

In addition, in the present embodiment, especially, hub 160 has concavity on the face towards bearing 20 of bearing cap 165 Oil groove 166.Thus, the grease of the substantial amounts of atomization of bearing 20 can be attached to oil groove 166, and can effectively suppress it Reveal to the side of encoder 100.

In addition, in the present embodiment, especially, the housing 150 of encoder 100 can be by with the first light absorbing colours Material is made, or the inner side of housing 150 can be applied as into the first light absorbing colours.Therefore, it is possible to further improve scattered light Or the reduction effect of veiling glare.

In addition, in the present embodiment, especially, housing 150 has the protuberance 153 prominent to tapering 164A sides.It is logical This protuberance 153 is crossed, the close tapering 164A of inwall of housing 150 can be made.As a result, protuberance 153 can absorb being bored The light of portion 164A reflections, and can further improve the reduction effect of scattered light or veiling glare.

Modified examples ＞ of ＜ 5.

The embodiment has been described in detail above with reference to accompanying drawing.However, the technology described in claims The scope of thought is not limited to herein described embodiment.For the those skilled in the art belonging to present embodiment Speech, it is obvious that this technology thought scope it is contemplated that and implementing various changes, variation and combinations thereof.Cause This, the model of the technological thought that should be considered to belong to of the invention certainly based on the technology of these changes, variation and combinations thereof Enclose.

(1) outer peripheral face of hub is the situation of the curved surface of arc-shaped

In the above-described embodiment, it is formed with inclining relative to optical axis h on the outer peripheral face of the main part 164 of hub 160 The constant tapering 164A of rake angle, but can continuously change relative to the angle of inclination of optical axis h.One of this modified example exists Illustrate in Fig. 4 and Fig. 5.In addition, in figures 4 and 5, pair with Fig. 2 and Fig. 3 identical structures, mark identical reference, and Its description is suitably omitted or simplified.

As shown in Figure 4 and Figure 5, the main part 167 of hub 160 is provided with curved face part 167A of arc-shaped on its outer peripheral face.It is bent Facial 167A is arranged in the isometrical portion 162B on top and between the bearing cap 165 of bottom, its upper end in light Axle h direction that be substantially parallel (that is, angle of inclination be 0 degree), its lower end in (that is, the inclination of optical axis h generally perpendicular directions Angle is 90 degree).In the present embodiment, as shown in figure 4, it is the arc-shaped apart from r that curved face part 167A is formed as radius of curvature, But the degree of crook not limited to this of curved face part.In addition, shown in Fig. 4 apart from d be isometrical portion 162B thickness (axis direction Distance).

According to this modified example, following effect is obtained in that.I.e., generally, when the part with constant angle of inclination connects During the diffusion light that receipts are projected from the light source 131 as spot light, in the light that reflection on the part of inner circumferential side is located at relative to optical axis h Easily towards receiving optical arrays PA sides, the light of approximate reflection on the part of outer circumferential side is being located at relative to optical axis h easily towards from receiving The direction that optical arrays PA leaves.In this modified example, to make the angle change relative to optical axis h in the way of constituted the portion Point.Specifically, the part can be configured to curved face part 167A that angle of inclination continuously changes.Therefore, because relative to Optical axis h is located at the angle of inclination of curved face part 167A of inner circumferential side becomes less, therefore, it is possible to make reflected light away from by optical arrays PA. On the other hand, because the angle of inclination that curved face part 167A of outer circumferential side is located at relative to optical axis h becomes larger, therefore, it is possible to by instead The direction for penetrating light is maintained from the direction left by optical arrays PA.As a result, scattered light or veiling glare can be improved further Reduce effect, and can further improve the accuracy of detection of encoder 100.

(2) situation of the angle of inclination step ground change of the outer peripheral face of hub

In the above-described embodiment, the inclination relative to optical axis h is formed on the outer peripheral face of the main part 164 of hub 160 The constant tapering 164A of angle, but can be changed with step relative to the angle of inclination of optical axis h.One illustration of this modified example In Fig. 6 and Fig. 7.In figure 6 and figure 7, pair mark identical reference is constituted with Fig. 2 and Fig. 3 identicals, and is suitably omitted Or simplified explanation.

As shown in Figure 6 and Figure 7, the main part 168 of hub 160 is configured to make its outer peripheral face relative to the inclination angle of optical axis h Degree is changed by the way that the neighbouring position of optical axis h is regarded as into border with two steps.Specifically, main part 168 is outside it Side face has superposed first tapering 168A and the second tapering 168B positioned at bottom.The angle of inclination of the first tapering 168A The angle of inclination being configured to than the second tapering 168B is little.In the example shown in Fig. 6, the first tapering 168A and the second tapering Border between 168B be located at the week side of boss more inner than optical axis h position, but not limited to this.For example, border can also be relative to Optical axis h is located at outer circumferential side, and the position on border can be with the position consistency of optical axis h.That is, border may be located at the attached of optical axis h Closely.

According to this modified example, the outer peripheral face of hub 160 relative to optical axis h angle of inclination relative to optical axis h it is vicinity, Easily direction is become less to reflected light by the inner circumferential side of optical arrays PA, relative to the vicinity of optical axis h, the easy direction of reflected light Become larger from the outer circumferential side in the direction left by optical arrays PA.Thus, even if in any of the inner circumferential side of optical axis h and outer circumferential side Position on, it is also possible to make the direction of reflected light from being left by optical arrays PA.As a result, scattered light or miscellaneous can be improved further The reduction effect of astigmatism, and can further improve the accuracy of detection of encoder 100.

Angle of inclination is illustrated using the situation that two steps change as one above, but can also inclination angle Degree is with three or more step changes.

(3) hub is by with the color (hereinafter, second that more light are absorbed compared with the color of the part in addition to hub Light absorbing colours) material constitute and be applied as the situation of the second light absorbing colours

In the above-described embodiment, hub 160 is not coated, but hub 160 can be coated in the second extinction Color (for example, black).Alternatively, hub 160 can be by the black such as carbon fiber material or the material structure with the second light absorbing colours Into.Thus, by tapering 164A can in light on by the direction not received on optical arrays PA reflected light, and can subtract The light quantity of few reflected light.Therefore, it is possible to the reduction effect for further improving scattered light or veiling glare.

(4) other

Above, to being used to for the hub 160 that disk 110 and axle sh are connected with each other to include rake inclined relative to optical axis h Situation be illustrated as one, but be not limited to hub 160 including the part of rake.For example, housing 150 or framework 10 Can be configured to include on the position at least on the optical axis h of light source 131 relative to the inclined inclinations of optical axis h of light source 131 Portion, so as to the reflected light on the direction that light is not received by optical arrays PA.

Above, the situation that hub 160 is fixed on the upper end of axle sh by bolt 14 is illustrated as one, but This is not limited to, hub 160 can be fixed on axle sh by binding agent.

In superincumbent explanation, " parallel ", " vertical " are not proper parallel and vertical.That is, it is " parallel " and " vertical Directly " representing respectively allows to design tolerance, " substantial parallel ", " substantial orthogonality " of error in upper, manufacture.Similarly, exist In explanation above, " equalization " is not proper equalization.That is, " equalization " is represented allows that design is upper, the tolerance in manufacture, " substantially impartial " of error.

An embodiment and modified example are illustrated above.But, in addition to the content for having described, can be by Above-mentioned embodiment or the method for each modified example is combined as utilizing.

It is not shown specifically, but can be without departing from the scope of the invention to above-mentioned embodiment Various changes are carried out with each modified example.

It should be appreciated by those skilled in the art, needed according to design and other factors, can carry out various changes, Combination, sub-portfolio and replacement, as long as they are in the range of claims or its equivalent.

Claims (12)

1. a kind of encoder, including：

The disk formed by the material through light；

The multiple reflecting parts being configured in along measurement direction on the disk；

It is configured to project the light source of light to the reflecting part；

Photo detector, the photo detector is configured to receive and is projected and in the light of reflecting part reflection by the light source；With And

Part, the part is configured in the opposition side of the light source on the disk, and with least described light source Optical axis on position on relative to the light source inclined light shaft part,

Wherein,

The Existential Space between the disk and the part,

The part is radiated into through the light of the disk via the space.

2. encoder according to claim 1, wherein,

The light source is the spot light for being configured to project diffusion light, and

The part is configured to change relative to the angle of inclination of the optical axis.

3. encoder according to claim 2, wherein,

The angle of inclination is configured to be regarded as border and changed with two steps by the neighbouring position of the optical axis.

4. encoder according to claim 1, wherein,

The part is the connection member for being configured to connect the disk and axle, and

The part be on the outer peripheral face of the connection member formed and with away from the disk with the axle center of the axle Centered on radical length increase tapering.

5. encoder according to claim 4, wherein,

The connection member includes：

Disk stationary plane, the disk can be fixed on the disk stationary plane；And

Isometrical portion, the isometrical portion is located between the disk stationary plane and the tapering, and is being fixed apart from the disk The distance on the axis direction in face is the equal length in the isometrical portion in the range of preset distance.

6. encoder according to claim 4, wherein,

The connection member have be configured to cover the surface of the disk side on the bearing for rotatably supporting the axle Bearing cap.

7. encoder according to claim 6, wherein,

The connection member has concave oil groove on the face towards the bearing of the bearing cap.

8. encoder according to claim 4, wherein,

The connection member is by with the color that more light are absorbed compared with the color of the part beyond the connection member Material is constituted, or

The connection member is coated in the color that more light are absorbed compared with the color of the part beyond the connection member.

9. encoder according to claim 4, also includes：

Housing, it is configured at least accommodate the disk, the light source, the photo detector and the part,

Wherein, the housing is by with the color that more light are absorbed compared with the color of the part beyond the connection member Material is constituted, or

The inside of the housing is coated in the face that more light are absorbed compared with the color of the part beyond the connection member Color.

10. encoder according to claim 9, wherein,

The housing has the protuberance prominent to the inclined part side.

11. encoders according to claim 5, wherein,

The connection member have be configured to cover the surface of the disk side on the bearing for rotatably supporting the axle Bearing cap.

12. encoders according to claim 11, wherein,

The connection member has concave oil groove on the face towards the bearing of the bearing cap.