CN117948392A - Internal circulation type ball screw - Google Patents

Abstract

The invention provides an internal circulation type ball screw, which comprises a screw shaft, a screw cap, a reflux component, a ball discharging channel and a ball discharging hole, wherein the screw cap is arranged on the screw shaft and forms a load path with the screw shaft, the screw cap is further provided with an accessory groove and the ball discharging hole communicated with the accessory groove, the reflux component is arranged in the accessory groove of the screw cap and forms a non-load path connected with the load path with the screw shaft, the non-load path and the screw shaft form a circulation path for balls to run together, the reflux component is further provided with the ball discharging channel, one end of the ball discharging channel is connected with an invalid tooth area of the internal thread groove of the screw cap, and the other end of the ball discharging channel is communicated with the ball discharging hole of the screw cap. Therefore, in the assembly process of the internal circulation ball screw, the balls which run to the ineffective tooth areas are allowed to run to the ball discharging holes through the ball discharging channels and then discharged to the outside of the screw cap through the ball discharging holes, so that the problems of overlarge resistance caused by the fact that the ineffective balls are clamped in the ineffective tooth areas and abrasion to related accessories are avoided.

Description

Internal circulation type ball screw

Technical Field

The invention relates to the field of ball screws, in particular to an internal circulation type ball screw.

Background

For the internal circulation ball screw, when the ball screw is applied in the low lead condition, as shown in fig. 1, the return grooves 2 of the return assembly 1 are usually designed to be a tooth jump, so as to avoid damage and failure of the return assembly 1 caused by too thin wall thickness between two adjacent return grooves 2. However, when assembling the reflow assembly 1 with the jump tooth design in cooperation with the balls 3, the assembler needs to take great care to make the balls 3 not drop out of the reflow grooves 2 as much as possible, and even so, some balls 3 still run into the ineffective tooth areas 4 between the adjacent two reflow grooves 2 to form ineffective balls 3', once the ineffective balls 3' are blocked in the ineffective tooth areas 4, they cannot be taken out, which causes excessive resistance in the subsequent operation and even wear on related accessories (such as screw shafts or nuts). In other words, the conventional reflow assembly 1 is time consuming and inconvenient to assemble in cooperation with the balls 3.

The return assembly according to the japanese patent No. 6444760 has a recovery port for recovering the lubricating oil and a discharge port for discharging the lubricating oil, respectively, in both arm portions, which are not for the balls to pass through, and thus there is no solution to the above-mentioned problem about the occurrence of the stuck ball in the ineffective dental region.

Disclosure of Invention

The invention mainly aims to provide an internal circulation type ball screw which can improve the assembly efficiency.

To achieve the above-mentioned main object, the present invention provides an internal circulation ball screw comprising a screw shaft, a nut, a closure, a return assembly, and a plurality of balls. The screw shaft is provided with an external thread groove; the nut is sleeved on the screw shaft and can move along the axial direction of the screw shaft, the nut is provided with an internal thread groove, a load path is formed between the internal thread groove of the nut and the external thread groove of the screw shaft, and in addition, the nut is also provided with an accessory groove which is radially communicated with the internal thread groove and a bead discharging hole which is radially communicated with the accessory groove; the backflow component is arranged in the accessory groove of the screw cap, the inner side surface of the backflow component is provided with a backflow groove, the backflow groove of the backflow component is connected with the inner thread groove of the screw cap and forms a non-load path with the outer thread groove of the screw shaft, the non-load path is connected with the load path to form a circulation path for the balls to move with the load path, in addition, the backflow component is also provided with a bead discharge channel adjacent to the backflow groove, the bead discharge channel penetrates through the inner side surface and the outer side surface of the backflow component, one end of the bead discharge channel is connected with a non-effective tooth area of the inner thread groove of the screw cap, and the other end of the bead discharge channel is communicated with the bead discharge hole of the screw cap.

From the above, the internal circulation ball screw of the invention allows the ineffective balls outside the reflux groove to reach the ball row hole from the ball row channel in the assembling process, and then the ineffective balls are discharged outside the nut from the ball row hole, and the sealing piece is sealed in the ball row hole after all the balls are assembled, so that the problems of overlarge resistance and abrasion to related accessories caused by the ineffective balls clamped in the nut can be solved.

Preferably, the reflow assembly has two bead rows with opposite extending directions and offset from each other, so as to allow the inactive beads to enter one of the bead rows, thereby facilitating the inactive beads to be discharged out of the nut.

Preferably, the bead row channel has an inlet formed on the inner side of the reflow assembly and an outlet formed on the outer side of the reflow assembly and communicating with the bead row hole of the nut. Whereby the inactive beads enter the bead discharge passage from the inlet and reach the discharge hole from the outlet.

Preferably, the reflow assembly further has a guiding protrusion adjacent to the inlet, and the inactive beads are guided into the bead row channel by the guiding protrusion.

Preferably, the inner peripheral surface of the nut is provided with a first groove, the inner side surface of the backflow component is provided with a second groove, the first groove and the second groove are mutually connected to form an inlet of the bead row channel, the bead row channel is also provided with an outlet, and the outlet is formed on the outer side surface of the backflow component and communicated with the bead row hole of the nut. Whereby the inactive beads enter the bead discharge passage from the inlet and reach the discharge hole from the outlet.

Preferably, the internal circulation ball screw of the present invention further comprises a sealing member disposed in the bead row hole of the nut for sealing the bead row hole.

Drawings

FIG. 1 is a partial cross-sectional view of a conventional reflow assembly assembled to a nut;

FIG. 2 is a perspective view of an internal circulation ball screw according to embodiment 1 of the present invention;

FIG. 3 is an exploded perspective view of an internal circulation ball screw according to embodiment 1 of the present invention;

FIG. 4 is a cross-sectional view of an internal circulation ball screw according to embodiment 1 of the present invention;

FIG. 5 is a top perspective view of a return assembly provided by an internal circulation ball screw of embodiment 1 of the present invention;

FIG. 6 is a bottom perspective view of a return assembly provided by an internal circulation ball screw of embodiment 1 of the present invention;

FIG. 7 is an axial partial sectional view of the omitted screw shaft of the internal circulation type ball screw according to embodiment 1 of the present invention;

FIG. 8 is a radial cross-sectional view of the internal circulation ball screw of embodiment 1 of the present invention with the screw shaft and closure omitted;

FIG. 9 is similar to FIG. 8 and mainly shows that one end of the hollow tube is inserted into the bead discharge channel;

Fig. 10 is a partial cross-sectional view of the internal circulation type ball screw omitted screw shaft of embodiment 2 of the present invention.

[ Reference numerals description ]

1-A reflow assembly; 2-a reflux groove; 3-balls; 3' -null beads; 4-ineffective dental area; 10-internal circulation ball screw; a 20-screw shaft; 22-an external thread groove; 30-screw cap; 32-internal thread grooves; 34-fitting slots; 36-bead row holes; 38-a closure; 40-a reflow assembly; 41-inner side; 42-outer side; 43-a reflux tank; 44-bead row channel; 45-inlet; 46-outlet; 47-guide projections; 50-rolling balls; 50' -null beads; 52-load path; 54-non-load path; 56-a circulation path; 58-ineffective dental area; 59-effective dental area; 60-hollow tube; 70-screw cap; 72-a first groove; 80-a reflow assembly; 82-second groove.

Detailed Description

The present invention will be further described in detail below with reference to specific embodiments and with reference to the accompanying drawings, in order to make the objects, technical solutions and advantages of the present invention more apparent. Applicant hereby gives notice that throughout this specification, including the examples presented below, directional terms are used to refer to the orientation of the drawing figures. Next, in the embodiments to be described below and the drawings, the same component numerals denote the same or similar components or structural features thereof.

Referring to fig. 2 and 3, the internal circulation ball screw 10 of embodiment 1 of the present invention comprises a screw shaft 20, a nut 30, a closure 38, a return assembly 40, and a plurality of balls 50.

The screw shaft 20 has an outer circumferential surface with an external thread groove 22 extending in an axial direction thereof.

The nut 30 is fitted over the screw shaft 20 and is movable in the axial direction of the screw shaft 20. The inner peripheral surface of the nut 30 has an internal thread groove 32 and a fitting groove 34 radially communicating with the internal thread groove 32, and a load path 52 (shown in fig. 4) is formed between the internal thread groove 32 of the nut 30 and the external thread groove 22 of the screw shaft 20. In addition, the nut 30 has a bead hole 36 penetrating the inner and outer peripheral surfaces, and the bead hole 36 communicates radially with the fitting groove 34.

The closure 38 may be tightly fitted, adhered or otherwise mounted within the bead aperture 36 of the nut 30 to close the bead aperture 36.

The return assembly 40 is disposed within the fitting recess 34 of the nut 30. As shown in fig. 5 and 6, the inner side 41 of the return assembly 40 has three return grooves 43 spaced apart, and the return grooves 43 of the return assembly 40 engage the internal thread grooves 32 of the nut 30 and form a non-load path 54 (as shown in fig. 4) with the external thread grooves 22 of the screw shaft 20 that engages the load path 52, such that the non-load path 54 and the load path 52 form a circulation path 56 (as shown in fig. 4) for the balls 50 to travel. In addition, as shown in fig. 5 and 6, the reflow assembly 40 has two bead rows 44 (actually, only at least one bead row is needed) between two adjacent reflow grooves 43, one end of each bead row 44 is connected with the ineffective tooth area 58 (as shown in fig. 7) of the internal thread groove 32 of the nut 30, the other end is connected with the bead row hole 36 of the nut 30, the extending directions of the bead row 44 are opposite and are arranged in a manner of mutually staggered front and back positions, each bead row 44 penetrates through the inner side surface 41 and the outer side surface 42 of the reflow assembly 40, and each bead row 44 has an inlet 45 and an outlet 46, in this embodiment, the inlet 45 is formed on the inner side surface 41 of the reflow assembly 40, and the outlet 46 is formed on the outer side surface 42 of the reflow assembly 40. As further shown in fig. 5, the inner side of the reflow assembly 40 has four guide protrusions 47, and the guide protrusions 47 are adjacent to the inlets 45 in a one-to-one manner. Here, as shown in fig. 7, the ineffective land 58 refers to a region through which the ball 50 does not flow when the nut 30 and the screw shaft 20 are cyclically rolled, whereas the effective land 59 refers to a region through which the ball 50 flows when the nut 30 and the screw shaft 20 are cyclically rolled.

As can be seen from the above, when the balls 50 are assembled, once the balls 50 run to the ineffective teeth 58 between the adjacent two of the backflow grooves 43, the balls 50 are regarded as ineffective balls 50', as shown in fig. 7 and 8, the ineffective balls 50' are guided by the guiding protrusions 47 to enter the ball discharging channel 44 from the inlet 45, then reach the ball discharging hole 36 from the outlet 46, and finally are directly discharged from the ball discharging hole 36 to the outside of the nut 30, so that the problem that the ineffective balls 50' are blocked in the ineffective teeth 58 can be solved, and finally the sealing member 38 seals the ball discharging hole 36 after all the balls 50 are assembled, so as to avoid foreign matters from the outside of the nut 30.

On the other hand, in order to allow the ineffective beads 50 'to be discharged more smoothly, as shown in fig. 9, a hollow tube 60 may be further inserted into the bead discharge channel 44 through the outlet 46, and the bead discharge channel 44 is blown or sucked, so that the ineffective beads 50' are discharged more rapidly to the outside of the screw cap 30 by the pressure of the gas, thereby improving the assembly efficiency.

It should be noted that, in the above embodiment, the inlet 45 of the bead discharging channel 44 is formed on the inner side 41 of the reflow assembly 40, however, in practice, the inlet 45 of the bead discharging channel 44 may be formed between the nut 70 and the reflow assembly 80, as shown in fig. 10, the inner circumferential surface of the nut 70 has a first groove 72, the inner side of the reflow assembly 80 has a second groove 82, and the first groove 72 and the second groove 82 are mutually engaged to form the inlet 45 of the bead discharging channel 44, so that the ineffective bead 50' can enter the bead discharging channel 44 from the inlet 45 to achieve the bead discharging effect.

In summary, the inner circulation ball screw 10 of the present invention allows the inactive balls 50 'that run to the inactive teeth 58 to be discharged from the ball discharge channel 44 to the outside of the nut 30 through the ball discharge hole 36 during the assembling process, so as to solve the problems of excessive resistance and wear on the related parts caused by the inactive balls 50' being blocked in the inactive teeth 58, thereby achieving the effect of improving the assembling efficiency.

While the foregoing is directed to embodiments of the present invention, other and further details of the invention may be had by the present invention, it should be understood that the foregoing description is merely illustrative of the present invention and that no limitations are intended to the scope of the invention, except insofar as modifications, equivalents, improvements or modifications are within the spirit and principles of the invention.

Claims (6)

1. An internal circulation ball screw comprising:

A screw shaft having an external thread groove;

The nut is sleeved on the screw shaft and can move along the axial direction of the screw shaft, the nut is provided with an internal thread groove, a load path is formed between the internal thread groove of the nut and the external thread groove of the screw shaft, and the nut is also provided with an accessory groove which is radially communicated with the internal thread groove and a bead discharging hole which is radially communicated with the accessory groove;

The backflow component is arranged in the accessory groove of the nut, the inner side surface of the backflow component is provided with a backflow groove, the backflow groove of the backflow component is connected with the internal thread groove of the nut, a non-load path is formed between the backflow groove and the external thread groove of the screw shaft, the non-load path is connected with the load path to form a circulation path with the load path, the backflow component is also provided with at least one bead discharge channel adjacent to the backflow groove, the at least one bead discharge channel penetrates through the inner side surface and the outer side surface of the backflow component, one end of the at least one bead discharge channel is connected with an invalid tooth area of the internal thread groove of the nut, and the other end of the bead discharge channel is communicated with the bead discharge hole of the nut; and

And a plurality of balls provided in the circulation path.

2. The internal circulation ball screw of claim 1, wherein the return assembly has two rows of ball channels extending in opposite directions and offset from each other.

3. The internal circulation ball screw according to claim 1 or 2, wherein the bead row passage has an inlet formed on an inner side of the return assembly and an outlet formed on an outer side of the return assembly and communicating with the bead row hole of the nut.

4. The internal circulation ball screw of claim 3, wherein the return assembly further has a guide boss adjacent the inlet.

5. The internal circulation ball screw according to claim 1 or 2, wherein the inner peripheral surface of the nut has a first groove, the inner side of the return assembly has a second groove, the first groove and the second groove are engaged with each other to form an inlet of the bead row passage, and the bead row passage further has an outlet formed on the outer side of the return assembly and communicating with the bead row hole of the nut.

6. The internally circulating ball screw of claim 1, further comprising a closure member disposed within the row of ball holes of the nut, the closure member configured to close the row of ball holes.