Improved double-arc thread raceway structure

Abstract

The utility model discloses an improved double-arc thread raceway structure, which belongs to ball screw transmission and aims to prolong the service life of a ball screw pair, and adopts the technical scheme that the improved double-arc thread raceway structure mainly comprises a ball screw, a ball nut and a ball, the ball screw is provided with a concave first thread groove, the ball nut is provided with a concave second thread groove, and the ball nut is provided with a second thread groove. The first thread groove and the second thread groove are double-arc thread grooves, after the first thread groove and the second thread groove make contact with the balls, an object collecting groove is formed in the bottom, and the first thread groove and the second thread groove are oppositely arranged to form a double-arc thread raceway. The ball screw pair is mainly used for improving the oil stain and dirt resistance of the ball screw pair and improving the heat dissipation condition of the ball screw pair, so that the transmission efficiency of the ball screw pair can be kept stable for a longer time.

Description

Technical Field

[0001] The utility model relates to an improved double-arc thread raceway structure, belonging to the technical field of ball screw transmission. Background Art

[0002] A ball screw pair is a precision transmission component that can convert linear motion into rotational motion or vice versa. A ball screw pair is mainly composed of a ball screw, a ball nut and balls. Ball screw pairs have the characteristics of high transmission efficiency and accurate positioning, and are widely used in aviation, aerospace, precision machine tools and other fields.

[0003] The threaded raceway is a spiral groove on the ball screw or ball nut for the ball to move. The ball screw pair transfers the load between the ball screw and the ball nut through the balls in the grooved raceway. The normal cross-section of the threaded raceway has two structural forms: single arc and double arc. Since the contact angle of the balls in the threaded raceway is less affected by the initial clearance and axial load changes, it can remain basically unchanged during operation. Its transmission efficiency, load-bearing capacity and axial stiffness are relatively stable. In particular, the bottom of the spiral groove does not contact the balls, and can accommodate a certain amount of grease and dirt, which is very beneficial to the smooth rolling of the balls. Therefore, most ball screw pairs in the existing technology use threaded raceways.

[0004] In the prior art, the normal cross-section of the threaded raceway is two circular arcs, and its structural parameters are: the contact angle α of the ball of the threaded raceway is 45°, and the ratio of the threaded raceway arc radius r to the ball diameter Dw is between 0.52 and 0.56; after the ball is assembled, although there is a certain space between the ball and the bottom of the spiral groove, the space is generally small, the ball screw pair has weak ability to resist oil and dirt, and the heat dissipation conditions are relatively poor; as the working time increases, the oil and foreign matter generated by friction and wear between the ball and the threaded raceway gradually increase, the rolling smoothness of the ball gradually decreases, resulting in a gradual decrease in the transmission efficiency of the ball screw pair, which ultimately affects the service life of the ball screw pair. Summary of the Invention

[0005] In order to solve the above technical problems, the utility model provides an improved double-arc thread raceway structure to increase the service life of the ball screw pair.

[0006] The utility model provides an improved double-arc thread raceway structure, including a ball screw, a ball nut and a ball, the ball screw is provided with a first concave thread groove, the ball nut is provided with a second concave thread groove, the first thread groove and the second thread groove are double-arc thread grooves, and a collection groove is formed at the bottom after the first thread groove and the second thread groove come into contact with the ball, and the first thread groove and the second thread groove are arranged opposite to each other to form a double-arc thread raceway.

[0007] Furthermore, the contact angle α between the double-arc thread raceway and the ball satisfies 30.8°≤α≤36.2°; and the ratio of the arc radius r of the double-arc thread raceway to the diameter Dw of the ball satisfies 1.04≤r:Dw≤1.12.

[0008] Furthermore, the contact angle α of the ball of the double-arc thread raceway satisfies 32.2°≤α≤34.8°.

[0009] Furthermore, the contact angle α of the ball of the double-arc thread raceway satisfies 33.2°≤α≤33.8°.

[0010] Furthermore, the ratio of the arc radius r of the double-arc thread raceway to the ball diameter Dw satisfies 1.06≤r:Dw≤1.10.

[0011] Furthermore, the ratio of the arc radius r of the double-arc thread raceway to the ball diameter Dw satisfies 1.07≤r:Dw≤1.09.

[0012] By adopting the above technical solution, the advantages of the utility model are: by reducing the contact angle between the double arc thread raceway and the ball from 45° to 30.8°~36.2°, the transmission efficiency obtained by the ball screw pair is slightly increased, and after increasing the ratio of the arc radius r of the double arc thread raceway to the ball diameter Dw from 0.52~0.56 to 1.04~1.12, the friction loss will increase; and after reducing the contact angle between the ball and the double arc thread raceway from 45° to 30.8°~36.2°, the transmission efficiency obtained by the ball screw pair is increased. This can just offset the effect of the increase in friction loss after the ratio of the arc radius r of the double-arc thread raceway to the ball diameter Dw increases from 0.52~0.56 to 1.04~1.12; however, after this change, a larger space is formed between the ball and the bottom of the first thread groove and the second thread groove, which not only improves the ability of the ball screw pair to resist oil and dirt, but also significantly improves its heat dissipation conditions. During operation, the transmission efficiency of the ball screw pair can remain stable for a longer period of time. Therefore, the service life of the ball screw pair will be greatly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Figure 1 This is a schematic diagram of the structure of the utility model including a ball screw, balls and ball nuts;

[0014] Figure 2 This is a schematic diagram of the structure of the utility model without ball screw, balls and ball nuts;

[0015] Figure 3 Schematic diagram of a double arc thread raceway structure in the prior art. DETAILED DESCRIPTION

[0016] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments.

[0017] In the specification and claims of this utility model, the terms "first," "second," and so on (if any) are used to distinguish similar items, not to describe a specific order or precedence. Even if "second" is used before a technical feature to distinguish it, it does not necessarily imply the presence of "first." It should be understood that in this utility model, "including," "having," and any variations thereof are intended to cover non-exclusive inclusions. It should be understood that in this utility model, "plurality" refers to two or more items. "And / or" is merely a description of an association between related items, indicating that three possible relationships exist. For example, "X and / or Y" can mean: X exists alone, X and Y exist simultaneously, or Y exists alone. The character " / " generally indicates that the related items are in an "or" relationship. "Including X, Y, and Z" means that all three of X, Y, and Z are included. "Including X, Y, or Z" means that any one of X, Y, or Z is included. "Including X, Y, and / or Z" means that any one, any two, or any three of X, Y, and Z are included. Example

[0018] like Figures 1 to 3 As shown, the utility model provides an improved double-arc thread raceway structure, including a ball screw 1, a ball nut 2 and a ball 3. The ball screw 1 is provided with a concave first thread groove 101, and the ball nut 2 is provided with a concave second thread groove 201. The first thread groove 101 and the second thread groove are double-arc thread grooves. After the first thread groove 101 and the second thread groove 201 come into contact with the ball, a collecting groove 5 is formed at the bottom. The first thread groove 101 and the second thread groove 201 are arranged opposite to each other to form a double-arc thread raceway 4.

[0019] The utility model sets the first thread groove 101 and the second thread groove 201 as double arc thread grooves, so that when the ball 3 is installed in the double arc thread raceway 4, gaps are left at the upper and lower ends to form a collecting groove 5. The collecting groove 5 not only improves the ability of the ball screw pair to resist oil and dirt, but also significantly improves its heat dissipation conditions. During operation, the transmission efficiency of the ball screw pair can remain stable for a longer period of time, so that the service life of the ball screw pair will be greatly improved.

[0020] Among them, the double arc thread groove is composed of two arcs of the same specifications to form a non-complete arc thread groove, so that when the ball 3 is installed in the double arc thread raceway 4, not the entire first thread groove 101 and the second thread groove 201 are in contact with the ball 3, only part of the arc surface is in contact with the ball 3, which slightly increases its transmission efficiency.

[0021] Specifically, the contact angle α between the double-arc thread raceway 4 and the ball satisfies 30.8°≤α≤36.2°; the ratio of the arc radius r of the double-arc thread raceway 4 to the diameter Dw of the ball 3 satisfies 1.04≤r:Dw≤1.12. The contact angle between the double-arc thread raceway 4 and the ball 3 is reduced from 45° to 30.8°~36.2°, and the transmission efficiency obtained by the ball screw pair is slightly increased. After the ratio of the arc radius r of the double-arc thread raceway 4 to the diameter Dw of the ball 3 is increased from 0.52~0.56 to 1.04~1.12, the friction loss will increase; and after the contact angle between the ball 3 and the double-arc thread raceway 4 is reduced from 45° to 30.8°~36.2°, the increase in the transmission efficiency obtained by the ball screw pair can just offset the effect of the increase in friction loss after the ratio of the arc radius r of the double-arc thread raceway 4 to the diameter Dw of the ball 3 is increased from 0.52~0.56 to 1.04~1.12. Example

[0022] The rest of the structure of this embodiment is the same as that of the first embodiment, but the contact angle α between the double arc thread raceway 4 and the ball is different from that of the first embodiment, where α satisfies 32.2°≤α≤34.8°. Example

[0023] The rest of the structure of this embodiment is the same as that of the first embodiment, but the contact angle α between the double arc thread raceway 4 and the ball is different from that of the first embodiment, where α satisfies 33.2°≤α≤33.8°. Example

[0024] The rest of the structure of this embodiment is the same as that of the first embodiment, but the ratio of the arc radius r of the double arc thread raceway 4 to the diameter Dw of the ball 3 is different from that of the first embodiment, wherein the ratio of r to Dw satisfies 1.06≤r∶Dw≤1.10. Example

[0025] The rest of the structure of this embodiment is the same as that of the first embodiment, but the ratio of the arc radius r of the double arc thread raceway 4 to the diameter Dw of the ball 3 is different from that of the first embodiment, wherein the ratio of r to Dw satisfies 1.07≤r∶Dw≤1.09.

[0026] In addition to the above-mentioned preferred embodiments, the present invention has other implementation methods. Based on the embodiments in the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative work are within the scope of protection requested by the present invention.

Claims

1. An improved double arc thread raceway structure, comprising a ball screw (1), a ball nut (2) and a ball (3), wherein the ball screw (1) is provided with a first concave thread groove (101), and the ball nut (2) is provided with a second concave thread groove (201), characterized in that: The first thread groove (101) and the second thread groove are double arc thread grooves. After the first thread groove (101) and the second thread groove (201) come into contact with the ball, a collection groove (5) is formed at the bottom. The first thread groove (101) and the second thread groove (201) are arranged relative to each other to form a double arc thread raceway (4). The contact angle α between the double arc thread raceway (4) and the ball satisfies 30.8°≤α≤36.2°. The ratio of the arc radius r of the double arc thread raceway (4) to the diameter Dw of the ball (3) satisfies 1.04≤r:Dw≤1.

12.

2. The improved double arc thread raceway structure according to claim 1, characterized in that: The contact angle α of the balls of the double arc thread raceway (4) satisfies 32.2°≤α≤34.8°.

3. The improved double arc thread raceway structure according to claim 2, characterized in that: The contact angle α of the balls of the double arc thread raceway (4) satisfies 33.2°≤α≤33.8°.

4. The improved double arc thread raceway structure according to claim 1, characterized in that: The ratio of the arc radius r of the double arc thread raceway (4) to the ball diameter Dw satisfies 1.06≤r∶Dw≤1.

10.

5. The improved double arc thread raceway structure according to claim 1, characterized in that: The ratio of the arc radius r of the double arc thread raceway (4) to the ball diameter Dw satisfies 1.07≤r∶Dw≤1.09.

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