Single-bearing type encoder shaft system structure

Abstract

The utility model relates to the technical field of encoders, in particular to a single-bearing type encoder shaft system structure, which is characterized in that a bearing inner ring is sleeved on a main shaft, the lower end of the main shaft is provided with a radial boss, and the radial boss is used for propping against the lower end surface of the bearing inner ring; the main shaft is provided with a thread matched with a locking nut above the radial boss, and the locking nut abuts against and is locked on the upper end face of the bearing inner ring; the rolling body abuts against the main body and the bearing inner ring. The rolling body comprises balls and pin rollers which are arranged alternately. According to the utility model, the bearing and the main body are integrated, and a traditional bearing outer ring is omitted; the design that the balls and the pin rollers are arranged alternately is adopted, a single-row bearing structure is achieved, and axial and radial gaps are effectively eliminated.

Description

Technical Field

[0001] The utility model relates to the technical field of encoders, and specifically provides a single-bearing encoder shaft system structure. Background Art

[0002] Encoders can be divided into split type and integral type according to their structural type. The integral photoelectric encoder has its own rotating reference and is composed of at least three basic parts: a shaft system, a grating disk, and a reading head. The shaft system is composed of multiple parts such as a main shaft, a bearing, and a main body. In the prior art, a rolling body is provided between the inner ring of the bearing and the outer ring of the bearing, and the rolling body is fixed by the outer ring of the bearing and the inner ring of the bearing. The connection reliability between the outer ring of the bearing and the main body and the stability of the rolling body will affect the coaxiality and end face runout accuracy of the encoder shaft system, and thus affect the stability of the entire encoder.

[0003] However, single-row ball bearings have problems such as severe end face vibration and unstable operation. Therefore, in order to improve the stability of the encoder during operation, Figure 1 As shown, the existing encoders usually adopt a double-row bearing design. Although the double-row bearing beads can improve the stability of the encoder during operation, the installation process of the double-bearing encoder is very complicated, and the position and angle of the two bearings need to be precisely adjusted to ensure their normal operation. If installed improperly, the encoder may be damaged or the measurement accuracy may be reduced. In addition, due to the superposition of machining errors of parts such as the inner ring of the bearing, the outer ring of the bearing, the balls, and the main body, the movement of the two balls will be asynchronous, which will aggravate the vibration and end face runout problems of the encoder, and then lead to a decrease in the encoder reading accuracy. Therefore, it is urgent to optimize the design of the encoder shaft system structure to improve the stability of the shaft system. Utility Model Content

[0004] In order to solve the above problems, the utility model provides a single-bearing encoder shaft system structure, cancels the traditional bearing outer ring, optimizes the design of the main body to replace the bearing outer ring, saves radial space, reduces one transfer, and thus improves the overall accuracy of the shaft system; and the axial clearance of conventional single-row bearings is much larger than the radial clearance. Taking deep groove ball bearings as an example, the general axial clearance is 6 to 8 times the radial clearance. If the shaft system is to run smoothly, two deep groove ball bearings must be used in pairs, and the axial clearance is eliminated by squeezing the inner rings of the two deep groove ball bearings toward each other to ensure the accuracy of the shaft system. The scheme adopts a design form of a combination of rollers and balls, in which the rollers are in linear contact with the inner and outer rings of the bearing, which can effectively reduce the relative swing of the inner and outer rings of the bearing, and then the axial clearance of the bearing is controlled within a smaller range through precision machining, and the cross-distributed balls can effectively reduce the friction torque compared to the design of all filled rollers, so this design scheme can achieve the clearance control effect of double-row bearings by using single-row bearings, saving axial space. At the same time, the special support of rollers greatly improves the overall radial and axial load-bearing capacity of the shaft system.

[0005] The single-bearing encoder shaft system structure provided by the utility model comprises: a main shaft, a main body, a bearing inner ring, a locking nut and a rolling element;

[0006] The inner ring of the bearing is sleeved on the main shaft, and a radial boss is provided at the lower end of the main shaft, which is used to abut against the lower end surface of the inner ring of the bearing; a thread matching a locking nut is provided above the radial boss of the main shaft, and the locking nut abuts against and locks against the upper end surface of the inner ring of the bearing;

[0007] The rolling elements are in contact with the main body and the inner ring of the bearing respectively, and the rolling elements include balls and rollers arranged alternately.

[0008] Preferably, the height of the roller is twice the diameter of the ball.

[0009] Preferably, the arrangement angle of the rollers and balls is 8 to 10 degrees.

[0010] Preferably, the contact angles between the ball and the main body and the inner ring of the bearing are all 58 degrees to 60 degrees.

[0011] Preferably, a glue storage groove is provided on the contact surface between the inner ring of the bearing and the main shaft, and the inner ring of the bearing and the main shaft are glued and fixed by injecting glue into the glue storage groove.

[0012] Compared with the prior art, the utility model can achieve the following beneficial effects:

[0013] The utility model integrates the bearing and the main body into one, cancels the traditional outer ring of the bearing, and reduces the number of parts of the encoder shaft system. On the one hand, it avoids the superposition of processing errors and installation errors of multiple parts, and on the other hand, it also saves the radial space occupied by the bearing structure. In addition, the utility model adopts the design of alternating arrangement of balls and rollers to realize a single-row bearing structure, avoids the existing double-bearing design, and effectively eliminates axial and radial clearances; the single-row bearing not only saves axial space, but also utilizes the special supporting performance of the rollers to further enhance the radial and axial load-bearing capacity of the shaft system. The encoder shaft system of the utility model effectively saves space in both the radial and axial directions, which has positive significance for the miniaturization of the encoder. In addition, the utility model optimizes the fixing method of the main shaft and the inner ring of the bearing, and uses a locking nut to limit and fix the inner ring of the bearing, which reduces the amplitude of the beating of the inner ring of the bearing and improves the stability of the encoder shaft system. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 It is a schematic diagram of the existing encoder shaft system structure provided in the background technology;

[0015] Figure 2 It is a schematic diagram of the shaft system structure of a single-bearing encoder provided according to an embodiment of the utility model;

[0016] Figure 3 It is a schematic diagram of the alternating arrangement of balls and rollers provided in an embodiment of the utility model;

[0017] Figure 4 is a schematic diagram of the contact angle between the ball and the body according to an embodiment of the utility model;

[0018] Figure 5 is a schematic diagram of the contact angle between the ball and the inner ring of the bearing according to an embodiment of the utility model;

[0019] Figure 6 It is a schematic diagram of the position of the glue storage slot provided according to an embodiment of the utility model.

[0020] Reference numerals include:

[0021] Spindle 1, main body 2, bearing inner ring 3, locking nut 4, ball 5, roller 6, glue storage groove 7, radial boss 8. DETAILED DESCRIPTION

[0022] Hereinafter, embodiments of the present utility model will be described with reference to the accompanying drawings. In the following description, the same modules are represented by the same reference numerals. In the case of the same reference numerals, their names and functions are also the same. Therefore, the detailed description thereof will not be repeated.

[0023] In order to make the purpose, technical solution and advantages of the utility model more clear, the utility model is further described in detail below in conjunction with the accompanying drawings and specific embodiments. It should be understood that the specific embodiments described here are only used to explain the utility model and do not constitute a limitation of the utility model.

[0024] like Figure 2 As shown, the embodiment of the utility model provides a single-bearing encoder shaft structure, which can be adapted to the existing integral photoelectric angle encoder. The shaft structure mainly includes: a spindle 1, a main body 2, a bearing inner ring 3, a locking nut 4 and a rolling element, wherein the spindle 1 is a rotating part of the encoder. During the use of the encoder, the spindle 1 is usually connected to a rotating device such as a motor shaft to rotate synchronously with the motor shaft. The spindle 1 is a hollow cylindrical shape as a whole, and the bearing inner ring 3 is sleeved on the spindle 2. A radial boss 8 is provided at the lower end of the spindle 1, and the lower end of the bearing inner ring 3 abuts against the upper surface of the radial boss 8, and the radial boss 8 is used to limit the bearing inner ring 3. Since the bearing inner ring 3 needs to rotate synchronously with the spindle 1, it is necessary to fix the position of the bearing inner ring 3 on the spindle 1. Therefore, a section of fine pitch thread is also provided above the radial boss 8, and the thread is matched with the internal thread of the locking nut 4. The distance between the lower end of the thread section and the upper surface of the radial boss 8 should be less than the height of the bearing inner ring 3. The locking nut 4 is screwed downward through a thread to abut and lock the upper end surface of the bearing inner ring 3. Compared with the existing fixing method, this fixing method can suppress the vibration amplitude of the bearing inner ring 3 to the greatest extent, thereby improving the stability of the encoder shaft system.

[0025] The embodiment of the utility model has specially designed the main body 2, eliminated the bearing outer ring in the traditional encoder shaft system, integrated the bearing outer ring directly on the main body 2, processed the side of the main body 2 with the bearing surface, and used the side of the main body 2 as the bearing outer ring, which effectively avoided the problem of fixing the bearing outer ring and the main body in the existing encoder. The integrated main body 2 can reduce the number of parts of the encoder shaft system, avoid the superposition of processing errors and installation errors between the bearing outer ring and the main body, and can also save the radial space occupied by the bearing outer ring and the main body, which has positive significance for the miniaturization of the encoder.

[0026] like Figure 3As shown, the embodiment of the utility model also has a special design for the rolling element, canceling the arrangement of the traditional double-row bearings and only using a single-row rolling element, and the rolling element abuts between the main body 2 and the inner ring 3 of the bearing. Since the stability of the single-row balls is relatively low, the vibration frequency and amplitude are obvious during the rolling process. Therefore, the rolling element is composed of balls 5 and rollers 6 that are alternately arranged, wherein the friction of roller 6 is relatively large, but the stability of roller 6 and the load-bearing capacity in the radial and axial directions are better, so the balls 5 and rollers 6 are arranged alternately, while improving the stability of the single-row rolling element, it also avoids introducing excessive friction. Among them, the height of roller 6 is twice the diameter of the ball. This design can balance the effects of stability and friction and maximize the performance of the encoder bearing. The arrangement angle of adjacent balls 5 and rollers 6 is between 8 and 10 degrees, ensuring the minimum gap while not increasing the overall friction torque. Under normal circumstances, the number of balls 5 and rollers 6 is 20 to ensure the uniformity of the rotation of the encoder bearing. As shown Figure 4 As shown, the contact angle between the ball 5 and the body 2 is between 58° and 60°. Figure 5 As shown, the contact angle between the ball 5 and the bearing inner ring 3 is the same as the contact angle between the ball 5 and the body 2, which is also between 58° and 60°, and the error range of the contact angle is ±1′.

[0027] As a preferred embodiment, Figure 6 As shown, a glue storage groove 7 is provided between the contact surfaces of the bearing inner ring 3 and the spindle 1 to further improve the stability and rigidity of the bearing inner ring 3 and the spindle 1. The axial height of the glue storage groove 7 is one third of the height of the bearing inner ring 3. By injecting glue into the glue storage groove 7, the bearing inner ring 3 and the spindle 1 are glued and fixed, which, on the one hand, improves the fixing strength of the bearing inner ring 3 and the spindle 1; on the other hand, it can also prevent dust and droplets outside the encoder from penetrating into the encoder through the contact gap between the bearing inner ring 3 and the spindle 1, causing pollution to the optical precision components inside the encoder.

[0028] Although the embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and cannot be understood as limiting the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention.

[0029] The above specific implementation methods of the utility model do not constitute a limitation on the protection scope of the utility model. Any other corresponding changes and modifications made according to the technical concept of the utility model should be included in the protection scope of the claims of the utility model.

Claims

1. A single-bearing encoder shaft system structure, characterized in that: include: Spindle, body, bearing inner ring, lock nut and rolling element; The inner ring of the bearing is sleeved on the main shaft, and a radial boss is provided at the lower end of the main shaft, and the radial boss is used to abut against the lower end surface of the inner ring of the bearing; the main shaft is provided with a thread matched with the locking nut above the radial boss, and the locking nut abuts against and locks the upper end surface of the inner ring of the bearing; The rolling bodies are respectively in contact with the main body and the inner ring of the bearing, and the rolling bodies include balls and rollers that are alternately arranged.

2. The single-bearing encoder shaft system structure according to claim 1, characterized in that: The height of the roller is twice the diameter of the ball.

3. The single-bearing encoder shaft system structure according to claim 2, characterized in that: The arrangement angle between the rollers and the balls is 8 to 10 degrees.

4. The single-bearing encoder shaft system structure according to claim 3, characterized in that: The contact angles between the ball, the main body and the inner ring of the bearing are all 58 degrees to 60 degrees.

5. The single-bearing encoder shaft system structure according to claim 1, characterized in that: The contact surface between the inner ring of the bearing and the main shaft is provided with a glue storage groove.

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