Multi-turn absolute value encoder

Abstract

The present application relates to a multi-turn absolute value encoder, comprising: an input shaft (10); the first single-circle absolute value encoding assembly (20) is used for detecting the absolute position of the input shaft in one circle; a rotating member (70) rotating synchronously with the input shaft and including an actuating portion (75); and a piezoelectric conversion mechanism (40) comprising a rolling-type media element, a pressing element (44) configured to be engageable with the actuating portion (75) via the media element so as to be actuated once by the actuating portion (75) in response to each full revolution of the rotating member (70), a piezoelectric element, and a reset element (46), a piezoelectric element engaged with the piezoelectric element and configured to cause the piezoelectric element to generate an electrical signal once when actuated by the actuation portion (75); and a reset element (46) engaged with the reset element (46) so as to be restored to an initial state in which the piezoelectric element is not actuated by the reset element after the pressing element (44) is actuated by the actuation portion (75).

Description

Technical Field

[0001] The present application relates to a multi-turn absolute encoder, and in particular to a battery-free multi-turn absolute encoder for detecting a rotation position. Background Art

[0002] The single-turn absolute encoder is the most basic encoder used to measure the rotational (or absolute) position within one turn, usually composed of a photoelectric sensor, a code disk, and a signal processor. The multi-turn absolute encoder not only measures the rotational (or absolute) position within one turn, but also measures the number of turns, and outputs both information. For both single-turn absolute encoders and multi-turn absolute encoders, after the encoder is powered off and then restored, the former can only record and restore position information within one turn, while the latter can record and restore position information within multiple turns, or can restore both absolute position and number of turns within one turn.

[0003] At present, there are two types of multi-turn absolute encoders: mechanical and electronic. Mechanical multi-turn absolute encoders use mechanical gears or gear sets. The center code disc is set on the center gear of the rotating shaft, and the corresponding photoelectric sensor reads the absolute position of the center gear, that is, the rotating shaft within one circle. The signal processor generates the absolute position of the center gear, that is, the rotating shaft within one circle. The driven code discs are set on one or a group of driven gears driven by the center gear, and the signal processor generates the number of circles of the center gear or the rotating shaft after reading the corresponding photoelectric sensor. This structure includes mechanical gear transmission components, so it is large in size and complex in structure.

[0004] Although electronic multi-turn absolute encoders do not use gear sets, they usually require memory to store the measured number of turns of the shaft, which makes it easy to lose the number of turns recorded in the memory in the event of an unexpected power outage of the encoder. Therefore, this type of encoder usually requires a backup power supply - a battery to power the memory in the event of an unexpected power outage to avoid loss of records in the memory. This brings about a series of related problems such as regular battery replacement and battery contamination. Utility Model Content

[0005] The purpose of this application is to provide a new multi-turn absolute encoder that overcomes the above-mentioned technical defects.

[0006] To this end, the present application provides a multi-turn absolute value encoder, comprising: an input shaft; a first single-turn absolute value encoding component, which is directly associated with the input shaft to detect the absolute position of the input shaft within one turn; a rotating member attached to the input shaft to rotate synchronously therewith and including an actuating portion; and a piezoelectric conversion mechanism, which comprises a dielectric element, an extrusion element, a piezoelectric element and a reset element, wherein the extrusion element is configured to: be able to engage with the actuating portion via the dielectric element so that it is actuated once by the actuating portion in response to each full rotation of the rotating member; engage with the piezoelectric element so that each time it is actuated by the actuating portion, the piezoelectric element generates an electrical signal; and engage with the reset element so that after each time the actuating portion actuates the extrusion element, the reset element restores the piezoelectric element to an initial state in which the piezoelectric element is not actuated, wherein the dielectric element is a rolling dielectric element that can roll relative to the extrusion element and / or the actuating portion.

[0007] In one embodiment, the dielectric element is one or more balls or rollers. In one embodiment, the extrusion element is configured to contact and squeeze the piezoelectric element only when it is actuated by the actuating portion of the rotating member; or the extrusion element is configured to always contact the piezoelectric element and the contact force between the two reaches a value that causes the piezoelectric element to generate an electrical pulse signal only when it is actuated by the actuating portion of the rotating member. In one embodiment, the extrusion element is supported only by the reset element or by the reset element and an additional element. In one embodiment, the reset element acts directly or indirectly on the extrusion element. In one embodiment, the reset element includes one or more springs and / or one or more blocks of elastic material. In one embodiment, the extrusion element translates and / or pivots when actuated by the actuating portion. In one embodiment, the rotating member includes a base fastened to the input shaft and an actuating portion protruding from the base.

[0008] In one embodiment, the piezoelectric element includes two different piezoelectric elements or includes two different piezoelectric element parts, and the extrusion element includes two different extrusion elements or two different extrusion parts that act on the two different piezoelectric elements or the two different piezoelectric element parts respectively when the rotating member rotates in different directions.

[0009] In one embodiment, the piezoelectric conversion mechanism further includes a cover member for preventing the dielectric element from being out of contact with the pressing element, and the cover member includes an opening through which the dielectric element is partially extended.

[0010] In one embodiment, the multi-turn absolute encoder further includes an electro-mechanical conversion mechanism associated with the piezoelectric element of the piezoelectric conversion mechanism and including a rotating shaft, so that the rotating shaft rotates a preset angle within one turn in response to the piezoelectric element generating a primary electrical signal.

[0011] In one embodiment, the multi-turn absolute encoder further comprises: a housing and the same or two separate fixing members fixed to the housing and used to support the piezoelectric conversion mechanism and the electro-mechanical conversion mechanism.

[0012] In one embodiment, the stationary member is a disc-shaped member surrounding the input shaft or a cantilevered element protruding inwardly from the housing.

[0013] In one embodiment, the piezoelectric conversion mechanism and the electro-mechanical conversion mechanism are arranged in one or two separate recesses formed on the fixing member.

[0014] In one embodiment, the electromechanical conversion mechanism further comprises a coil winding configured to receive an electrical signal from the piezoelectric conversion mechanism and generate a magnetic field causing the rotating shaft to rotate.

[0015] In one embodiment, the multi-turn absolute encoder also includes a second single-turn absolute encoding component, which is associated with the rotating shaft of the electro-mechanical conversion mechanism to detect the absolute position of the rotating shaft within one turn, and the absolute position of the rotating shaft within one turn corresponds to the number of turns rotated by the input shaft.

[0016] In one embodiment, each of the first single-turn absolute value encoder assembly and the second single-turn absolute value encoder assembly comprises: an encoder disk, a photoelectric sensor for reading the encoding on the encoder disk, and a processor circuit for converting the code read by the photoelectric sensor into an electrical signal output.

[0017] The multi-turn absolute value encoder of the present application adopts two (or dual) single-turn absolute value encoding components, which are respectively used to detect or obtain the rotation (rear) position of the rotating shaft within one turn and the number of turns of the rotating shaft. The advantage of using two single-turn absolute value encoding components is that when the entire multi-turn absolute value encoder is powered on again after an unexpected power failure, the codes on the encoding disk read by the photoelectric sensors of the two single-turn absolute value encoding components and the signals output by the processor circuit correspond to the rotation (rear) position and the number of turns of the input shaft of the encoder at this moment. In particular, for the single-turn absolute value encoding component used for the function of detecting the number of turns, no data storage function is required, and no backup power supply is required, eliminating the technical problems related to the backup power supply. More advantageously, since there is no need for a power-off storage function for the data related to the number of turns, there is no situation where the data is accidentally lost due to unstable power (external interference) which may occur in the configuration that uses electrical (signal) energy to provide a power-off storage function. Furthermore, the single-turn absolute value encoding assembly for detecting the number of turns does not use a gear structure by associating a piezoelectric (or electromechanical) conversion mechanism that converts rotational mechanical energy into electrical energy and an electromechanical conversion mechanism that converts electrical energy into rotational mechanical energy to the input shaft of the encoder. This eliminates the problems of large mass, large volume, and large noise associated with the gear structure. Specifically, the piezoelectric conversion mechanism adopts a structure in which a rotating member that rotates with the input shaft actuates an extrusion element via a rolling dielectric element, and an electrical signal is generated when the contact or extrusion force applied by the extrusion element to the piezoelectric element reaches a preset value. Due to the presence of the rolling dielectric element, the energy loss during the energy conversion process is minimized, the energy conversion efficiency is high, and the electrical signal is stable. The electromechanical conversion mechanism adopts a motor-like structure that combines a coil winding that generates a magnetic field when receiving an electrical signal generated by the piezoelectric conversion mechanism and a rotating shaft that can rotate in the magnetic field. It has the advantages of a compact structure and a small size of the entire encoder. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The accompanying drawings constitute part of the specification and are used to explain the principles of the present application and provide a further understanding of the above and other features and advantages of the present application, but do not limit the scope of protection. In the accompanying drawings:

[0019] Figure 1 It is an exemplary structural diagram of the multi-turn absolute encoder of the present application.

[0020] Figure 2 and 3 Shows Figure 1 The working principle of the piezoelectric conversion mechanism of the multi-turn absolute encoder. DETAILED DESCRIPTION

[0021] The exemplary embodiments of the present application are described clearly and completely below in conjunction with the accompanying drawings. It should be noted that the embodiments shown in the accompanying drawings and described herein are only exemplary embodiments that can implement the principles of the present application, rather than all embodiments. They are only used to illustrate the principles of the present application and are not intended to limit the scope of protection of the present application.

[0022] Figure 1 The schematic structural diagram of a multi-turn absolute encoder 100 constructed according to the principle of the present application is shown. The encoder 100 first includes a housing 12 and an input shaft 10. The input shaft 10 extends outward from the inside of the housing 12 and is used to connect with the rotating body to be detected, so that it rotates synchronously with the rotating body to be detected during the detection process. For example, but not necessarily, the input shaft 10 can be arranged in the center of the housing 12.

[0023] The multi-turn absolute encoder 100 of the present application is configured to detect the multi-turn rotation of the rotating body to be detected connected to the input shaft 10, and the "multi-turn rotation" includes two parts: the number of full turns of the rotating body, also called "the number of turns" or "the absolute value of the number of turns"; and the rotational position of the rotating body within one turn or the absolute position of the rotating body (after rotation), also called "the absolute position within one turn" or "the absolute position of a single turn". Therefore, the multi-turn absolute encoder 100 is used to output two aspects of information representing "the number of turns" and "the absolute position within one turn".

[0024] According to the principle of the present application, the multi-turn absolute value encoder 100 adopts two single-turn absolute value encoding components, which are used as a single-turn absolute position detection device and a number of turns (absolute value) detection device to detect or obtain the above-mentioned "single-turn absolute position" and "number of turns". In the present application, the term "single-turn absolute value encoding component" has the function of a "single-turn absolute value encoder" well known to those skilled in the art, and generally refers to an encoding component or device known in the art for detecting an absolute (or rotational) position within a circle. In general, the "single-turn absolute value encoding component" may include an encoding disk for installation on a rotating shaft so as to rotate with the rotating shaft, a photoelectric sensor for reading the real-time encoding on the encoding disk, and a processor circuit for converting the real-time encoding read by the photoelectric sensor into a signal in a specific form (e.g., an electrical signal in the form of a pulse) for output. Therefore, the signal output by the "single-turn absolute value encoding component" uniquely represents or corresponds to the code presented in real time on its encoding disk, and thus uniquely represents or corresponds to the rotation or absolute position of the rotating shaft on which the encoding disk is installed (and rotates synchronously with it).

[0025] like Figure 1As shown, the multi-turn absolute encoder 100 includes two single-turn absolute encoder components arranged in a housing 12: a first single-turn absolute encoder component 20 as a single-turn absolute position detection device and a second single-turn absolute encoder component 30 as a turn number detection device. Both single-turn absolute encoder components 20 and 30 are in the form of photoelectric encoding components, and respectively include: encoder disks 22 and 32 in the form of grating code disks, photoelectric sensors 24 and 34 for reading grating codes, and processor circuits (not shown in detail) for converting the codes read by the photoelectric sensors 24 and 34 into electrical signal outputs. Each of the photoelectric sensors 24 and 34 may include light emitters 24a and 34a and light receivers 24b and 34b.

[0026] The encoding disk 22 of the first single-turn absolute value encoding assembly 20 is directly attached to the input shaft 10 of the encoder 100 and rotates with the input shaft 10, so the real-time code read from the encoding disk 22 by the photoelectric sensor 24 and the electrical signal converted and output by the corresponding processor circuit uniquely represent or correspond to the single-turn (within one turn) absolute position of the input shaft 10 (or the rotating body to be detected).

[0027] The second single-turn absolute value encoder assembly 30 is associated with the input shaft 10 via a motion conversion device, and the motion conversion device includes a piezoelectric conversion mechanism 40 engaged with the input shaft 10 and an electromechanical conversion mechanism 50 engaged with the second single-turn absolute value encoder assembly 30. The piezoelectric conversion mechanism 40 and the electromechanical conversion mechanism 50 of the motion conversion device are engaged, so that when the input shaft 10 rotates through any different number of circles, the output member-the rotating shaft 55 of the electromechanical conversion mechanism 50 rotates to (or presents) different positions within a circle, whereby the different positions of the rotating shaft 55 of the electromechanical conversion mechanism 50 within one circle uniquely correspond to the number of circles of the input shaft 10 engaged with the piezoelectric conversion mechanism 40.

[0028] The encoding disk 32 of the second single-turn absolute value encoding assembly 30 is engaged or attached to the rotating shaft 55 of the electro-mechanical conversion mechanism 50, and is driven by the rotating shaft 55 to rotate synchronously. Therefore, the real-time code read from the encoding disk 32 by the photoelectric sensor 34 and the signal converted and output by the corresponding processor circuit uniquely represent or correspond to the single-turn (within one circle) absolute position of the rotating shaft 55, and thus uniquely represent or correspond to the number of turns made by the input shaft 10.

[0029] Based on the above principle, the encoder 100 composed of two single-turn absolute value encoder components 20 and 30 and a motion conversion device can detect and output both the number of turns and the absolute position within one turn.

[0030] For the two single-turn absolute value encoding components 20 and 30 used in the encoder 100, the configuration and principle of the single-turn absolute value encoding components including the encoding disk, photoelectric sensor and processor circuit are known in the art, are not the focus of this application, and are not described in detail here.

[0031] It should be noted that the two single-turn absolute value encoding components 20 and 30 of the encoder 100 can have any possible configuration under the premise of being able to achieve the above functions, and the configurations adopted by the two can be the same or different. Although the two single-turn absolute value encoding components are illustrated in this application as, but not limited to, single-turn absolute value encoding component configurations based on photoelectric principles, any single-turn absolute value encoding component can be replaced by a structure known in the art that can detect single-turn absolute position based on principles such as magnetoresistance or magnetoelectricity.

[0032] For example, the encoder disks 22 and 32 of the two single-turn absolute value encoder assemblies 20 and 30 can be any code disks of the same or different forms known in the art, such as Gray code, BCD code, hexadecimal code, etc. The encoder disk can be a grating code disk including a plurality of code tracks consisting of light-transmissive parts and light-impermeable parts, and the grating code disk can provide a predetermined number of codes. The number of codes that the encoder disks 22 and 32 can provide can be selected as needed, and common examples include, but not limited to, 2 10 , 2 12 , 2 13 , 2 14 , 10 16 For example, the encoder disk 22 of the first single-turn absolute value encoder assembly 20 for detecting the single-turn absolute position can be selected based on the desired accuracy or resolution of the single-turn absolute position of the input shaft 10, and the encoder disk 32 of the second single-turn absolute value encoder assembly 30 for detecting the absolute value of the number of turns can be selected based on the maximum number of turns that the input shaft 10 may have rotated and the desired resolution, so that any possible number of turns of the input shaft 10 can be reflected by the unique corresponding code within one turn on the encoder disk 32. The encoder disks 22 and 32 can provide the same or different numbers of codes.

[0033] In addition, the present application does not limit the fixing or attachment method of the code disk 22 or 32 of each single-turn absolute value encoder assembly 20 or 30 to the respective corresponding shaft (input shaft 10 or rotating shaft 55). As a non-limiting example only, the code disk 22 of the first single-turn absolute value encoder assembly 20 is shown as being fastened to the input shaft 10 through the cylindrical mounting portion 23 and, for example, by means of a fastener 27.

[0034] Furthermore, it is also understood that the photoelectric sensor 24 or 34 and the processor circuit of each single-turn absolute value encoder assembly 20 or 30 may be supported by the housing 12 or any stationary component mounted to the housing 12. As a non-limiting example, the photoelectric sensor 34 and its processor circuit of the second single-turn absolute value encoder assembly 30 are shown to be supported by a fixed member 60 to be described in detail later.

[0035] It should be pointed out here that since the device for detecting the single-turn absolute position and the device for detecting the absolute value of the number of turns both use single-turn absolute value encoding components, the multi-turn absolute value encoder of the present application can provide all the advantages that single-turn absolute value encoding components can provide. Even if the multi-turn absolute value encoder of the present application is accidentally powered off, when the encoder is restored to power, the outputs of the two single-turn absolute value encoding components 20 and 30 also correspond to the absolute position of the input shaft 10 within one turn and the number of turns at this moment, because: for the first single-turn absolute value encoding component 20 for detecting the single-turn absolute position, the code of its encoding disk corresponds to the absolute position of the input shaft 10 within one turn at any time, so when power is restored, its output corresponds to the absolute position of the input shaft 10 within one turn (regardless of whether the input shaft continues to rotate during the power outage); for the second single-turn absolute value encoding component 30 for detecting the absolute value of the number of turns, if the input shaft 10 rotates during this power outage, the encoder will The rotating member 70 of the encoder (even during power failure) rotates synchronously with the input shaft 10, and the piezoelectric conversion mechanism 40 (not dependent on or requiring the power supply of the encoder) continues to work to generate an electric pulse signal corresponding to the number of turns of the input shaft 10. The operation of the electro-mechanical conversion mechanism 50 rotating the shaft 55 in response to the electric pulse signal generated by the piezoelectric conversion mechanism 40 also does not depend on or require the power supply of the encoder. Similarly, the code of the encoder disk of the second single-turn absolute value encoder component 30 corresponds to the absolute position of the shaft 55 within one turn at any time, so at any time (regardless of whether the encoder is powered off), the output of the second single-turn absolute value encoder component 30 corresponds to the number of turns of the input shaft 10 at that time. Therefore, the single-turn absolute value encoder component 30 is used to detect the absolute value of the number of turns, and there is no need to provide a power failure memory function, and the encoder 100 does not need to be equipped with a backup power supply.

[0036] The following describes in detail the motion conversion device that links the second single-turn absolute value encoder assembly 30 to the input shaft 10. As described above, the motion conversion device includes both the piezoelectric conversion mechanism 40 and the electro-mechanical conversion mechanism 50.

[0037] The piezoelectric conversion mechanism 40 can adopt any possible piezoelectric converter known in the art for converting mechanical motion into an electrical signal and outputting the signal. It is associated with the input shaft 10 and is configured to output an electrical signal when the input shaft 10 rotates a full circle. For example, the electrical signal can be an electrical signal in the form of a pulse having a preset waveform (such as a square wave).

[0038] refer to Figure 1 , the encoder 100 may include a fixed member 60 fixed to the housing 12 so as to remain stationary during the rotation of the input shaft 10. The fixed member 60 may be, but not necessarily, in the form of a disc-shaped member extending around the input shaft 10 as shown, and may be in the form of a cantilever protruding inwardly from the housing 12 if functional requirements are met. Both the piezoelectric conversion mechanism 40 and the electro-mechanical conversion mechanism 50 are supported by the fixed member 60, for example, the piezoelectric conversion mechanism 40 and the electro-mechanical conversion mechanism 50 are at least partially accommodated in recesses 41 and 51 formed on the fixed member 60, respectively.

[0039] The encoder 100 may further include a rotating member 70 that is fastened to the input shaft 10 and rotates together with the input shaft 10 during rotation. The rotating member 70 may include a flat plate-shaped base 72 fastened to the input shaft 10 and an actuating portion 75 extending from the base 72. Figure 2 and 3 It can be seen from the enlarged view that the actuating portion 75 is in the form of a protrusion or projection protruding from the base 72 toward the piezoelectric conversion mechanism 40. However, the present application is not limited thereto, and the rotating member 70 can be designed in association with the piezoelectric conversion mechanism 40, as long as it can be achieved that the actuating portion 75 passes through and actuates the piezoelectric conversion mechanism 40 once (so that the piezoelectric conversion mechanism 40 generates an electrical signal in the form of a pulse) every time the rotating member 70 rotates one circle with the input shaft 10.

[0040] Specific reference Figure 2 and 3According to an exemplary structure, the piezoelectric conversion mechanism 40 may include: first and second piezoelectric elements 42a and 42b, a pressing element 44 including first and second pressing portions 44a and 44b for contacting (and pressing) the first and second piezoelectric elements 42a and 42b, respectively, one or more (for example, two are shown in the figure) elastic elements (for example, springs) 46 for elastically supporting the pressing element 44 in the recess 41, and one or more balls 48 as rolling medium elements. Only one ball 48 is shown as an example in the figure, but it is conceivable that one or more rows of balls are arranged in the circumferential direction and / or radial direction along the rotation direction of the input shaft 10. The first and second pressing portions 44a and 44b of the pressing element 44 respectively include first and second arc surface portions 45a and 45b that are spaced apart but belong to different parts of the same spherical surface. The piezoelectric conversion mechanism 40 may further include a cover 80 for holding the ball 48 in contact with the arcuate surface portions 45a and 45b of the pressing element 44 and preventing the ball 48 from being separated from these surface portions, and including an opening 82 for allowing the ball 48 to partially extend out of the recess 41 and enter the gap G. As is apparent from the figure, the gap G is defined between the base 72 of the rotating member 70 and the opposing surfaces 71 and 61 of the fixed member 60, and the actuating portion 75 of the rotating member 70 and the ball 48 of the piezoelectric conversion mechanism 40 at least partially protrude into the gap G, so that the actuating portion 75 can actuate the ball 48 during the rotation of the rotating member 70. The present application does not limit the structural form of the cover 80.

[0041] Figure 2 The rotating member 70 is shown in a state where the actuating portion 75 thereof is about to (but has not yet) actuate the piezoelectric conversion mechanism 40 (specifically the ball 48), that is, the piezoelectric conversion mechanism 40 is still in a default non-actuated state. In this state, with the help of the elastic element 46, the ball 48 is sandwiched between the cover 80 and the pressing element 44 and partially extends through the opening 82 of the cover 80, and the first and second pressing portions 44a and 44b of the pressing element 44 do not contact the corresponding first and second piezoelectric elements 42a and 42b. The piezoelectric conversion mechanism 40 does not generate any electrical signal.

[0042] As the rotating member 70 rotates in the direction indicated by the arrow, the actuating portion 75 pushes the ball 48, and the ball 48 applies pressure to the arc surface 45a of the first pressing portion 44a of the pressing element 44, and at least one (for example, one corresponding to the piezoelectric element 42a) elastic element 46 is compressed, and the pressing element 44 is tilted in a manner that the first pressing portion 44a approaches the first piezoelectric element 42a (correspondingly, the second pressing portion 44b moves away from the second piezoelectric element 42b), and then gradually contacts and presses the first piezoelectric element 42a. Figure 3As shown, when the actuating portion 75 of the rotating member 70 passes approximately directly above the ball 48, the magnitude of the squeezing force applied by the first squeezing portion 44a to the first piezoelectric element 42a reaches a preset maximum value sufficient to cause the first piezoelectric element 42a to generate the above-mentioned pulse-shaped electrical signal. The piezoelectric conversion mechanism 40 generates an electrical pulse signal having the above-mentioned preset waveform.

[0043] After the actuating portion 75 of the rotating member 70 moves over the ball 48, under the action of the restoring force of the elastic element 46, the pressure applied by the first pressing portion 44a to the first piezoelectric element 42a gradually decreases until the two are out of contact, and the piezoelectric conversion mechanism 40, specifically the first piezoelectric element 42a, no longer generates an electrical signal, and the elastic element 46, the pressing element 44 and the ball 48 return to the state as shown in FIG. Figure 2 location.

[0044] Similarly, when the rotating member 70 rotates in the direction opposite to the arrow shown in the figure, the actuating portion 75 tilts the pressing element 44 in the opposite direction via the ball 48 in a similar manner as described above, and the second pressing portion 44b contacts and presses the second piezoelectric element 42b to generate an electric pulse signal. Finally, as the actuating portion 75 moves away from the ball 48, the electric pulse signal disappears.

[0045] As described above, when the input shaft 10 rotates once in any rotation direction, the rotating member 70 rotates once, and its actuating portion 75 actuates the piezoelectric conversion mechanism 40 once, and the latter (the piezoelectric element 42a or 42b) generates an electric pulse signal. Therefore, the number of electric signals generated by the piezoelectric conversion mechanism 40 is the number of revolutions of the input shaft 10, or in other words, the piezoelectric conversion mechanism 40 converts the number of revolutions of the input shaft 10 into the same number of electric pulse signals.

[0046] As described above, the electric pulse signal generated by the piezoelectric conversion mechanism 40 is provided as input to the electromechanical conversion mechanism 50 (for example, via the conductive member 49-wire shown in the figure), and then the rotational motion is output by the output member of the electromechanical conversion mechanism 50-the rotating shaft 55.

[0047] return Figure 1 The electromechanical conversion mechanism 50 may be partially arranged in the recess 51 of the fixing member 60. As an exemplary structure of the electromechanical conversion mechanism 50, it may include (for example, via Figure 1The conductive member 49 of the piezoelectric conversion mechanism 40 is connected to the coil winding 52 electrically connected to the piezoelectric elements 42a and 42b of the piezoelectric conversion mechanism 40, and the rotating shaft 55 passes through the coil winding 52. Therefore, each time the coil winding 52 receives an electrical signal from the piezoelectric element 42a or 42b, a magnetic field is generated, and the magnetic field force causes the rotating shaft 55 to rotate by a preset angle. In other words, in response to an electrical pulse signal generated by the piezoelectric conversion mechanism 40 every time the input shaft 10 and the rotating member 70 rotate one circle, the rotating shaft 55 rotates by the above-mentioned preset angle under the action of the magnetic field generated by the coil winding 52. Therefore, the number of circles rotated by the input shaft 10 and the rotation position (rotated angle) of the rotating shaft 55 uniquely and accurately corresponds.

[0048] The code disk 32 of the second single-turn absolute value encoder assembly 30 of the encoder 100 is mounted on the rotating shaft 55. The preset angle that the rotating shaft 55 rotates in response to an electrical pulse signal is designed to enable the photoelectric sensor 34 of the second single-turn absolute value encoder assembly 30 to just read the next code on the code disk 32. As described in detail above, the output signal of the second single-turn absolute value encoder assembly 30 uniquely corresponds to the rotation position of the rotating shaft 55 within one circle, and therefore uniquely represents or corresponds to the number of circles that the input shaft 10 has rotated.

[0049] The exemplary embodiment of the multi-turn absolute value encoder 100 of the present application is described in detail above with reference to the accompanying drawings, and the principle of the present application is explained. Since the multi-turn absolute value encoder 100 of the present application adopts two single-turn absolute value encoding components 20 and 30, the device for detecting the absolute value of the number of turns (the second single-turn absolute value encoding component 30) no longer needs a power-off memory function, and does not need to provide a backup power supply, thereby eliminating all problems related thereto.

[0050] As described above, the second single-turn absolute value encoder assembly 30 for detecting the number of turns of the multi-turn absolute value encoder 100 is associated with the input shaft 10 through a motion conversion device composed of a piezoelectric conversion mechanism 40 and an electro-mechanical conversion mechanism 50. Specifically, the piezoelectric conversion mechanism 40 is supported by a fixed member 60 fixed to the housing 12, and is directly engaged with an actuating portion 75 of a rotating member 70 fastened to the input shaft 10, thereby realizing the function of the piezoelectric conversion mechanism 40 being actuated once by the rotating member 70 for each rotation of the input shaft 10. However, in the case of realizing the above-mentioned engagement and actuation relationship between the actuating portion 75 and the piezoelectric conversion mechanism 40, the structural details of the fixed member 60, the rotating member 70 and the piezoelectric conversion mechanism 40 are not limited to the illustrated embodiment. The piezoelectric conversion mechanism 40 does not have to be arranged in the recess 41 of the fixed member 60, and the structural details of the rotating member 70 can also be modified as needed, as long as its actuating portion 75 can realize the function of actuating the piezoelectric conversion mechanism 40.

[0051] Although in the illustrated embodiment, the piezoelectric conversion mechanism 40 and the electro-mechanical conversion mechanism 50 are both disposed on the same fixed member 60, separate fixed or stationary members may be provided for the piezoelectric conversion mechanism 40 and the electro-mechanical conversion mechanism 50. In some embodiments, the specific structure of the fixed member 60 and / or the relative positional relationship of the two recesses 41 and 51 on which the above-mentioned mechanisms 40 and 50 are mounted may be changed according to the needs of the actual structure or arrangement.

[0052] In order to realize the detection function when the input shaft 10 rotates in two rotation directions, the multi-turn absolute encoder 100 of the present application is provided with two piezoelectric elements 42a and 42b corresponding to the two rotation directions respectively in the piezoelectric conversion mechanism 40, but those skilled in the art should understand that this is not necessary. The number, arrangement and specific structural form of the piezoelectric elements can be changed according to actual needs, as long as it is ensured that the extrusion element 44 of the piezoelectric conversion mechanism 40 can contact and squeeze the piezoelectric element (or a part thereof) to generate an electrical signal when the input shaft 10 rotates in any rotation direction. For example, the two piezoelectric elements 42a and 42b shown in the figure can be the same piezoelectric element or different parts of the same piezoelectric element. Unlike the two extrusion parts 44a and 44b for the two piezoelectric elements 42a and 42b shown in the figure provided by the same extrusion element 44, the piezoelectric conversion mechanism 40 may include two separate extrusion elements for the two piezoelectric elements 42a and 42b.

[0053] The figure also illustrates that the arcuate surface portions 45a and 45b of the two extrusion portions 44a and 44b of the extrusion element 44 are separated by a notch 49a, and the extrusion element 44 also includes a notch 49b arranged roughly symmetrically with the notch 49a on the surface opposite to the arcuate surface portions 45a and 45b. This is conducive to the extrusion element 44 responding more quickly and moving toward the corresponding piezoelectric element when the actuating portion 75 passes through the ball 48, and is conducive to the subsequent faster resetting of the extrusion element 44.

[0054] Although the illustrated example includes a dielectric element in the form of a ball 48, the piezoelectric conversion mechanism 40 can be designed to not include a dielectric element, and a configuration is also possible in which the actuating portion 75 of the rotating member 70 directly actuates the pressing element and the pressing element contacts and presses the piezoelectric element when actuated.

[0055] In the illustrated example, a rolling dielectric element in the form of a ball 48 is used. In the process of the actuator 75 moving past the ball 48, the ball 48 not only applies pressure to the arcuate surface portions 45a and 45 of the extrusion element 44, but also rolls against the arcuate surface portions 45a and 45 of the extrusion element 44. The ball 48 and the actuator 75 also have a rolling motion relative to each other, which reduces the resistance of the actuator 75 when passing by, and reduces energy loss, compared with the friction motion in the form of translation relative to each other. At the same time, those skilled in the art can imagine that the ball 48 can be replaced by other rolling elements such as rollers. The number and arrangement of rolling elements can also be changed as needed. The applicant also imagines that non-rolling dielectric elements can be used.

[0056] In the illustrated number, the extrusion element 44 including two extrusion parts 44a and 44b is supported in the recess 41 only by the elastic element 46, and is tilted toward the corresponding piezoelectric element 42a or 42b when indirectly acted upon by the actuating portion 75. In some variant embodiments, the method for supporting the extrusion part 44 in the recess 41 can be changed. For example, a rigid support element can also be provided, supported at the notch 49b. For another example, the relative positional relationship between the elastic element 46 and the piezoelectric element can be changed. The extrusion element 44 does not have to be supported at the bottom of the side away from the actuating portion 75. The elastic element 46 used as a recovery element is not limited to a spring, for example, it can be replaced by a block of elastic material.

[0057] In some processes not shown, the piezoelectric conversion mechanism 40 can be simply constructed to include a piezoelectric element, a pressing element and a reset element, so that when the rotating member 70 rotates a full circle in any rotation direction, the actuating portion 75 directly presses the pressing element, and the pressing element contacts and presses the piezoelectric element to generate an electric pulse signal. After the actuating portion 75 passes, the reset element restores the pressing element to its original position. On this basis, according to the principles of this application, the applicant has envisioned the following possible variations:

[0058] The actuation portion 75 may actuate the extrusion element in any manner, directly or indirectly (e.g., via a rolling or non-rolling dielectric element);

[0059] The extrusion element may be supported in any suitable manner by a member that is fixed relative to the housing 12;

[0060] The pressing element can be moved in any movement mode until the piezoelectric element is actuated when actuated by the actuating portion 75, for example: a translational and / or pivotal movement mode;

[0061] The pressing element may be configured to move from non-contact with the piezoelectric element to contact with the piezoelectric element and then press the piezoelectric element when the actuating portion 75 of the rotating member 70 is actuated, as described above with reference to the drawings, or may be configured to always be in contact with the piezoelectric element, but only when the actuating portion 75 of the rotating member 70 is actuated, the contact force of the pressing element on the piezoelectric element reaches a value sufficient to cause the piezoelectric element to generate an electrical pulse signal;

[0062] The pressing element may be configured to be supported only by the resetting element, as described above with reference to the drawings, or may be configured to have an additional supporting element;

[0063] The reset element may also be designed to directly or indirectly act on or support the extrusion element in any possible manner so that the extrusion element returns to its original position after the actuating portion 75 passes by;

[0064] The restoring element acts on or supports any part of the pressing element.

[0065] In addition to the specific configuration of the electro-mechanical conversion mechanism 50 described above with reference to the drawings, any mechanism capable of converting an electrical pulse signal into a rotational motion may be adopted.

[0066] Some exemplary embodiments that can implement the present application are described in detail above with reference to the accompanying drawings. The above description and the accompanying drawings are only for explanation and illustration purposes, and the scope of protection of the present application is limited only by the claims. Modifications, equivalent replacements and improvements made to the structural details by those skilled in the art after reading the present application are all included in the scope of protection of the present application.

Claims

1. A multi-turn absolute encoder, comprising: an input shaft (10); a first single-turn absolute value encoder assembly (20) directly associated with the input shaft (10) to detect the absolute position of the input shaft (10) within one turn; a rotating member (70) attached to the input shaft (10) to rotate synchronously therewith and including an actuating portion (75); and a piezoelectric conversion mechanism (40), The piezoelectric conversion mechanism (40) comprises a dielectric element, a pressing element (44), a piezoelectric element and a reset element (46), wherein the pressing element (44) is configured to: be able to engage with the actuating portion (75) via the dielectric element so that the actuating portion (75) actuates the piezoelectric element once in response to each full rotation of the rotating member (70); engage with the piezoelectric element so that the piezoelectric element generates an electrical signal each time it is actuated by the actuating portion (75); and engage with the reset element (46) so that each time the actuating portion (75) actuates the pressing element (44), the reset element restores the piezoelectric element to an initial state in which the piezoelectric element is not actuated, wherein the dielectric element is a rolling dielectric element capable of rolling relative to the pressing element (44) and / or the actuating portion (75).

2. The multi-turn absolute encoder according to claim 1, characterized in that One or more of the following: The dielectric element is one or more balls or rollers; The pressing element (44) is configured to contact and press the piezoelectric element only when actuated by the actuating portion (75) of the rotating member (70); Or the pressing element (44) is configured to always contact the piezoelectric element and the contact force between the two reaches a value that causes the piezoelectric element to generate an electrical pulse signal only when it is actuated by the actuating portion (75) of the rotating member (70); The pressing element (44) is supported only by the restoring element (46) or by both the restoring element (46) and the additional element; The resetting element (46) acts directly or indirectly on the extrusion element; The reset element (46) comprises one or more springs and / or one or more elastic material blocks; The pressing element (44) translates and / or pivots when actuated by the actuating portion (75); The rotating member (70) includes a base portion (72) fastened to the input shaft (10) and an actuating portion (75) protruding from the base portion (72).

3. The multi-turn absolute encoder according to claim 2, characterized in that: The piezoelectric element includes two different piezoelectric elements (42a, 42b) or includes two different piezoelectric element parts, and the pressing element (44) includes two different pressing elements or two different pressing parts (44a, 44b) that act on the two different piezoelectric elements or the two different piezoelectric element parts respectively when the rotating member (70) rotates in different directions.

4. The multi-turn absolute encoder according to claim 3, characterized in that: The piezoelectric conversion mechanism (40) further includes a cover member (80) for preventing the dielectric element from being out of contact with the pressing element (44), the cover member including an opening (82) through which the dielectric element is partially extended.

5. The multi-turn absolute encoder according to any one of claims 1 to 4, characterized in that It also includes an electro-mechanical conversion mechanism (50), which is associated with the piezoelectric element of the piezoelectric conversion mechanism (40) and includes a rotating shaft (55), so that in response to the piezoelectric element generating a primary electrical signal, the rotating shaft (55) rotates within a circle at a preset angle.

6. The multi-turn absolute encoder according to claim 5, characterized in that Also includes: A housing (12) and the same or two separate fixing members (60) fixed to the housing (12) and used to support the piezoelectric conversion mechanism (40) and the electro-mechanical conversion mechanism (50).

7. The multi-turn absolute encoder according to claim 6, characterized in that: The fixed member (60) is a disc-shaped member surrounding the input shaft (10) or a cantilevered element protruding inwardly from the housing.

8. The multi-turn absolute encoder according to claim 7, characterized in that: The piezoelectric conversion mechanism (40) and the electro-mechanical conversion mechanism (50) are arranged in one or two separate recesses (41, 51) formed on the fixing member (60).

9. The multi-turn absolute encoder according to claim 5, characterized in that: The electro-mechanical conversion mechanism (50) further includes a coil winding (52) configured to receive an electrical signal from the piezoelectric conversion mechanism (40) and generate a magnetic field causing the rotating shaft (55) to rotate.

10. The multi-turn absolute encoder according to claim 5, characterized in that It also includes a second single-turn absolute value encoding component (30) which is associated with the rotating shaft (55) of the electro-mechanical conversion mechanism (50) to detect the absolute position of the rotating shaft (55) within one turn, and the absolute position of the rotating shaft (55) within one turn corresponds to the number of turns made by the input shaft (10).

11. The multi-turn absolute encoder according to claim 10, characterized in that: Each of the first single-turn absolute value encoding assembly (20) and the second single-turn absolute value encoding assembly (30) comprises: an encoding disk, a photoelectric sensor for reading the encoding on the encoding disk, and a processor circuit for converting the encoding read by the photoelectric sensor into an electrical signal output.

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