JPH0228404Y2 - - Google Patents

Description

[Detailed Description of the Invention] <Technical Field of the Invention> The present invention relates to a rotary encoder used to detect the rotational speed, position, etc. of an object. This invention relates to a hydrostatic levitation type rotary encoder that levitates using.

<Background of the invention> As shown in FIG. 5, in a conventional rotary encoder, a rotating disk 62 is attached and fixed to a rotating shaft 61 supported in a case 6, and a light emitting/receiving element is attached to the inner surface of the case 6 in correspondence with the rotating disk. The light emitting/receiving element holder 7 has a light emitting element 72 on one side, a fixed slit 73 and a light receiving element 74 on the other side, facing both sides of a rotating disk running groove 71, and has a fixed slit 73 and a light receiving element 74 on the other side. A rotary disk 62 is located in the center of the space of the running groove 71. However, in the above structure, the rotating disk 62 generates vibrations due to high-speed rotation, and is easily damaged by coming into contact with the fixed slit 73, and there is a risk that light transmission may be hindered. This is one of the reasons why the speed is limited and the gap between the rotary disk 62 and the fixed slit 73 cannot be set small.

<Purpose of the invention> This invention creates a new hydrostatically floating rotary encoder with excellent reliability and durability by using air pressure to levitate the light emitting/receiving sensor unit to the rotating disk and maintain it in a non-contact state. The purpose is to provide.

<Description of Embodiment> FIG. 1 shows a hydrostatic levitation type rotary encoder according to an embodiment of the present invention.
A rotating disk 2 fixedly attached to a rotating shaft 21 and a light emitting/receiving sensor unit 3 that is a feature of the present invention.
It is equipped with The light emitting/receiving sensor unit 3 is
The upper and lower unit members 31 and 32 are arranged facing each other, and a storage chamber 33 for the rotary disk 2 is formed between them.
A flying clearance h, h of several microns is set between the two and 32. Further, the upper unit member 31 incorporates a light emitting element 34 such as a light emitting diode or a lamp, and the lower unit member 32 incorporates a fixed slit 35, a light receiving element 36, and an amplifier circuit section 37. communicate with each other to form an air passage 4, the base end of the air passage 4 is connected to a pressure air source via an air supply pipe 41, and the distal end is connected to a floating gap h formed above and below the rotary disk 2, h and air outlets 42 and 43 opened opposite the rotation shaft 21, so that the light emitting and receiving sensor unit 3 floats relative to the rotation shaft 21 and the rotation disk 2, and the unit 3 is supported by support means 5 between it and the case 1. The support means 5 has a V-groove 51 vertically arranged in the same direction as the rotating shaft 21 on the front, rear, right and left sides of the light emitting/receiving sensor unit 3, and a spring ball 53 having an adjustment screw 52 is provided on the inner surface of the case 1. The spring ball 53 is engaged with the V-groove 51, and the light emitting/receiving sensor unit 3 is supported movably in the axial direction of the rotating shaft 21 by the urging of the spring.

When pressurized air is supplied from the air supply pipe 41 to the air passage 4, as shown in FIG. However, the pressure in the pocket portion 44 increases. Due to this air pressure, the upper and lower unit members 31 and 32 float away from the surface of the rotary disk 2, and as shown in FIG. Localize at the position of value h.

Therefore, in this floating state, the light emitting/receiving sensor unit 3 is
If the rotary disk 2 is rotated while supplying pressurized air, the non-contact state can be maintained even during the detection operation, and the rotary disk 2 can be rotated at an extremely high speed.

<Effects of the invention> As described above, in the present invention, the light emitting/receiving sensor unit is levitated by pressurized air and maintained in a non-contact state with respect to the rotating shaft and the rotating disk. A floating gap of several microns can be set between the two, resulting in high resolution. Further, due to the non-contact, there is no risk of damage to the rotary disk, and deterioration of light transmission characteristics can be prevented, and reliability and durability can be significantly improved. Furthermore, since the dust on the surface of the rotating disk is blown away by the jet of pressurized air, there is no need for a dust-proof structure as in conventional devices, and the configuration and assembly work can be simplified, achieving the effects of the invention.

[Brief explanation of the drawing]

FIG. 1 is a vertical cross-sectional view of a rotary encoder according to an embodiment of the present invention, and FIG.
3 is an enlarged sectional view of the air jet nozzle, FIG. 4 is a diagram showing the air jet nozzle and its pressure distribution, and FIG. 5 is a sectional view of a conventional example. DESCRIPTION OF SYMBOLS 1... Case, 4... Air passage, 2... Rotating disk, 42, 43... Air outlet, 21... Rotating shaft, 5... Supporting means, 3... Light emitting/receiving sensor unit.

Claims (1)

[Scope of utility model registration request] A light emitting/receiving sensor unit is provided on both sides of the rotating disk, and the light emitting/receiving sensor unit is provided with air jet ports communicating with the air supply section at several locations facing the circumferential surface of the rotating shaft and on both surfaces of the rotating disk. The light emitting/receiving sensor unit is a hydrostatic floating rotary encoder supported on the case via a mounting means that is movable in the axial direction of the rotating shaft.