WO2024101083A1

WO2024101083A1 - Linear motion guide device

Info

Publication number: WO2024101083A1
Application number: PCT/JP2023/037477
Authority: WO
Inventors: 貴光冨山; 彬趙; 和也志岐
Original assignee: Thk株式会社
Priority date: 2022-11-08
Filing date: 2023-10-17
Publication date: 2024-05-16
Also published as: JP2024068238A

Abstract

Provided is a linear motion guide device with which a satisfactory lubrication state can be maintained over an extended period of time. The linear motion guide device comprises: a first guide rail (1); a second guide rail (2) capable of moving relative to the first guide rail (1); rolling elements (3a, 3b) capable of rolling along raceway surfaces (1a, 1b) of the first guide rail (1) and raceway surfaces (2a, 2b) of the second guide rail (2); and a retainer (4) for retaining the rolling elements (3a, 3b). The retainer (4) comprises a first portion (11) and a second portion (12) that are combined. Lubricant pockets (9) that come into contact with rolling surfaces of the rolling elements (3a, 3b) are provided in the retainer (4) by forming notches (8) in a joining surface (5) of at least one of the first portion (11) and the second portion (12).

Description

Linear guide device

The present invention relates to a linear guide device that has a first guide rail and a second guide rail that are movable relative to each other.

A linear guide device is known that includes a first guide rail and a second guide rail that are capable of relative movement (see Patent Document 1). Rolling elements are disposed between the raceway surface of the first guide rail and the raceway surface of the second guide rail. When the second guide rail moves relative to the first guide rail, the rolling elements move linearly while rolling between the raceway surfaces. To keep the spacing between the rolling elements constant, the rolling elements are held in a cage. The cage moves linearly in conjunction with the linear movement of the rolling elements. This type of linear guide device is provided to enable relative movement of the components of the device.

Unlike a recirculating type linear guide device, in this type of linear guide device, the rolling elements move linearly without coming off the raceway surface of the first guide rail and the raceway surface of the second guide rail. For this reason, the stroke of the second guide rail relative to the first guide rail is finite. When the second guide rail repeatedly moves relative to the first guide rail, the cage becomes unstable due to external influences such as uneven tightening or internal influences such as shape errors in the raceway surface. To prevent this, the cage may be provided with a pinion portion that meshes with the rack portion, and the position of the cage may be controlled by the rack portion and pinion portion.

JP 2012-21572 A

When assembling the linear guiding device to a device, a lubricant such as grease is applied to each component of the linear guiding device (first guide rail, second guide rail, rolling elements). It is difficult to apply lubricant to each component of the linear guiding device when it is assembled into the device, so after the initial application, it is desirable to maintain a good lubricated state for a long period of time.

However, because the cages of conventional linear guide devices are formed in a plate shape, there is no sufficient space to store lubricant in the cage, making it difficult to maintain good lubrication over the long term.

The present invention was made in consideration of the above problems, and aims to provide a linear guide device that can maintain good lubrication conditions for a long period of time.

In order to solve the above problem, one aspect of the present invention is a linear guide device that includes a first guide rail, a second guide rail that is movable relative to the first guide rail, rolling elements that are capable of rolling on the raceway surface of the first guide rail and the raceway surface of the second guide rail, and a retainer that holds the rolling elements, in which the retainer includes a first part and a second part that are combined together, and a notch is formed in the joint surface of at least one of the first part or the second part to provide the retainer with a pocket for lubricant that contacts the rolling surface of the rolling elements.

According to the present invention, it is possible to store lubricant in the lubricant pockets that come into contact with the rolling surfaces of the rolling elements, so that good lubrication can be maintained for a long period of time.

1 is a perspective view of a linear guide device according to a first embodiment of the present invention; FIG. 2 is a perspective view of the linear guide device of the present embodiment (with the second guide rail shown in cross section to show the internal structure). FIG. 2 is a side view of the linear guide device of the present embodiment. FIG. 2 is a perspective view of a retainer of the linear guide device of the present embodiment. 5(a) is an enlarged view of part V in FIG. 4, FIG. 5(b) is a perspective view showing the first part with the second part removed, and FIG. 5(c) is a perspective view of the first part with the second part and rollers removed. FIG. 2 is an enlarged perspective view of a portion of the retainer of the linear guide device of the embodiment. FIG. 7(a) is a perspective view of a first portion of a cage of a linear guide device according to a second embodiment of the present invention, and FIG. 7(b) is an enlarged view of portion b of FIG. 7(a). FIG. 8(a) is a perspective view of a first portion (with rollers removed) of a cage of a linear guide device according to a second embodiment of the present invention, and FIG. 8(b) is an enlarged view of portion b of FIG. 8(a).

Hereinafter, a linear guide device according to an embodiment of the present invention will be described with reference to the accompanying drawings. However, the linear guide device of the present invention can be embodied in various forms and is not limited to the embodiments described in this specification. The present embodiment is provided with the intention of enabling a person skilled in the art to fully understand the invention by fully disclosing the specification.
First Embodiment

Figures 1 to 3 show a linear guide device according to a first embodiment of the present invention. 1 is a first guide rail, and 2 is a second guide rail. The second guide rail 2 is movable relative to the first guide rail 1 in the longitudinal direction. The first guide rail 1 is attached to a fixed part of the device. The second guide rail 2 is attached to a movable part of the device. The first guide rail 1 and the second guide rail 2 are formed with mounting holes 1c, 2c such as countersinks for mounting to the device.

The first guide rail 1 has

raceway surfaces

1a and 1b formed with a V-shaped cross section. The second guide rail 2 also has

raceway surfaces

2a and 2b formed with a V-shaped cross section. A number of rollers are arranged as rolling elements between the

opposing raceway surfaces

1a and 2a and between the

raceway surfaces

1b and 2b. As shown in FIG. 2, a number of

rollers

3a and 3b are arranged alternately (so that the axes of

adjacent rollers

3a and 3b are perpendicular) between the

raceway surfaces

1a and 2a and between the

raceway surfaces

1b and 2b. The side surface (rolling surface) of roller 3a contacts the

raceway surfaces

1a and 2a. The side surface (rolling surface) of roller 3b contacts the

raceway surfaces

1b and 2b. When the second guide rail 2 moves relative to the other, the rolling surface of roller 3a rolls on the

raceway surfaces

1a and 2a, and the rolling surface of roller 3b rolls on the

raceway surfaces

1b and 2b.

The

rollers

3a and 3b are held in the retainer 4 with their rolling surfaces and bottom surfaces exposed. The retainer 4 has, for example, a roughly rectangular cross section and extends in the length direction of the first guide rail 1 and the second guide rail 2.

As shown in FIG. 4, the cage 4 comprises a first part 11 and a second part 12 that are assembled together. The first part 11 and the second part 12 come into contact at a joint surface 5 and are joined by a snap fit. The joint surface 5 is disposed in a plane that includes the axes of every

other roller

3b, 3b. The material of the first part 11 and the second part 12 is not particularly limited, and may be resin, metal, etc.

As shown in Figures 5(a) and (b), the first part 11 is formed with an elastically deformable hook-shaped engaging part 6. A claw portion 6a is formed at the tip of the engaging part 6. The second part 12 is formed with a window portion 12a into which the claw portion 6a of the engaging part 6 of the first part 11 engages. Similarly, the second part 12 is formed with an elastically deformable engaging part 7. A claw portion is formed at the tip of the engaging part 7. The first part 11 is formed with a window portion 11a into which the claw portion of the engaging part 7 of the second part 12 engages. The first part 11 and the second part 12 are formed to be substantially the same shape. The second part 12 is the first part 11 turned upside down.

As shown in Figures 5(b) and (c), the first portion 11 is provided with

roller pockets

13, 14 by forming recesses in the joining surface 5. The roller pocket 13 is formed in a roughly short cylindrical shape so that it can accommodate the lower half of the roller 3a. The roller pocket 13 is formed with a rectangular opening 13a that exposes the rolling surface of the roller 3a, and a circular opening 13b that exposes the bottom surface of the roller 3a.

The roller pocket 14 is formed in a semi-cylindrical shape so that it can accommodate the lower half of roller 3b, which is tilted 90 degrees relative to roller 3a. The roller pocket 14 is formed with a rectangular opening 14a that exposes the rolling surface of roller 3b, and a semicircular opening 14b that exposes the bottom surface of roller 3b.

The first part 11 has a lubricant pocket 9 formed by forming a stepped or other notch 8 on the joint surface 5. The lubricant pocket 9 is a space that can be filled with lubricant. The lubricant pocket 9 contacts the rolling surfaces of the

rollers

3a, 3b so that lubricant can be applied to the rolling surfaces of the

rollers

3a, 3b. As shown in FIG. 5(a), when the first part 11 and the second part 12 are combined, the lubricant pocket 9 is provided on the outer surface of the cage 4. The lubricant pocket 9 is located between the

adjacent rollers

3a and 3b.

As shown in Figures 5(b) and (c), the lubricant pocket 9 is provided around the engagement portion 6. The engagement portion 6 rises from the bottom surface of the lubricant pocket 9 and extends beyond the joint surface 5 to the window portion 12a of the second part 12. A space is also formed between the engagement portion 6 and the spacer portion 16 by the notch 8. A rib 6b that reinforces the engagement portion 6 is formed at the bottom of the engagement portion 6 (see also Figure 6).

As shown in FIG. 5(c), a lubricant pocket 19 is provided in the first portion 11 by forming a stepped or other notch 18. A lubricant pocket 9 is provided at one end of the first portion 11 in the width direction, and a lubricant pocket 19 is provided at the other end. This lubricant pocket 19 is also a space that can be filled with lubricant. The lubricant pocket 19 contacts the rolling surfaces of the

rollers

3a, 3b so that lubricant can be applied to the rolling surfaces of the

rollers

3a, 3b.

As shown in FIG. 6, when the first part 11 and the second part 12 are combined, the lubricant pocket 9 of the first part 11 communicates with the lubricant pocket 19 of the second part 12. The lubricant pocket 19 is exposed to the outer surface of the cage 4 through the window portion 12a.

As shown in FIG. 4, a disk-shaped pinion portion 21 is rotatably provided in the center of the retainer 4. A plurality of projections (gears) 21a are formed on the outer periphery of the pinion portion 21, protruding radially at a constant circumferential pitch. A hole (not shown) is formed in each of the first and

second portions

11 and 12, into which the shaft of the pinion portion 21 is fitted.

As shown in Figures 1 and 2, the pinion portion 21 is disposed between the first guide rail 1 and the second guide rail 2. A rack portion with which the pinion portion 21 meshes is provided in the device to which the linear guide device is attached. The position of the retainer 4 is controlled by the rack portion and the pinion portion 21. The rack portion may be provided on at least one of the first guide rail 1 or the second guide rail 2.

The following describes the function and effects of the linear guide device of this embodiment.

When assembling the linear guide device to the device, a lubricant such as grease is applied to the raceway surfaces 1a and 1b of the first guide rail 1, the raceway surfaces 2a and 2b of the second guide rail 2, the

rollers

3a and 3b, and the pinion portion 21. At this time, the lubricant pockets 9 and 19 of the retainer 4 are also filled with lubricant.

The lubricant pockets 9, 19 are spaces that come into contact with the rolling surfaces of the

rollers

3a, 3b. Therefore, by storing lubricant in the lubricant pockets 9, 19, the lubricant can be applied from the lubricant pockets 9, 19 to the rolling surfaces of the

rollers

3a, 3b. As a result, good lubrication can be maintained for a long period of time.

Since the lubricant pockets 9, 19 are provided on the outer surface of the retainer 4 when the first part 11 and the second part 12 are combined, the lubricant pockets 9, 19 can be filled with lubricant when the retainer 4,

rollers

3a, 3b, and pinion part 21 are assembled.

Since the lubricant pocket 9 is provided around the engaging portion 6, the lubricant pocket 9 can be used as a space for deflecting the engaging portion 6.
Second Embodiment

Figures 7 and 8 show a retainer 30 of a linear guide device according to a second embodiment of the present invention. Only the first part 31 of the retainer 30 is shown in Figures 7 and 8. The second part of the retainer 30 has substantially the same shape as the first part 31, and the second part is the inverted version of the first part 31. However, while the first part 31 has a hole 31a formed therein, the second part has a pin that fits into the hole 31a formed therein.

In the second embodiment, the first part 31 and the second part of the retainer 30 are welded together. That is, the pin of the second part is inserted into the hole 31a of the first part 31, and the first part 31 and the second part are welded together in a state where the joint surface 35 of the first part 31 and the joint surface of the second part are aligned.

As shown in FIG. 8, the first part 31 has roller pockets 13, 14 formed therein, similar to the first part 11 of the first embodiment. The shapes of the roller pockets 13, 14 are substantially the same as those of the first part 11 of the first embodiment, so they are given the same reference numerals and their description is omitted.

In the first part 31, a lubricant pocket 37 is provided by forming a stepped or other notch 36 in the joint surface 35. A lubricant pocket 37 is also provided in the second part. The lubricant pocket 37 is a space that can come into contact with the rolling surfaces of the

rollers

3a and 3b. By filling the lubricant pocket 37 with lubricant, the lubricant can be applied from the lubricant pocket 37 to the rolling surfaces of the

rollers

3a and 3b.

The present invention is not limited to the above embodiment, but can be embodied in other embodiments without departing from the spirit of the present invention.

In the above embodiment, multiple rollers are arranged in a cross-staggered manner on the retainer, but multiple rollers may also be arranged in parallel.

In the above embodiment, rollers are used as the rolling elements, but balls may also be used as the rolling elements.

In the above embodiment, the retainer is provided with a pinion portion, but the pinion portion may be omitted.

This specification is based on Patent Application No. 2022-178533, filed November 8, 2022, the entire contents of which are incorporated herein by reference.

1...first guide rail, 1a, 1b...raceway surface of first guide rail, 2...second guide rail, 2a, 2b...raceway surface of second guide rail, 3a, 3b...rollers (rolling elements), 4...retainer, 5...joint surface, 6...engagement portion, 7...engagement portion, 8...notch, 9...lubricant pocket, 11...first part, 12...second part, 18...notch, 19...lubricant pocket, 30...retainer, 31...first part, 35...joint surface, 36...notch, 37...lubricant pocket

Claims

A first guide rail;
A second guide rail that is movable relative to the first guide rail;
a rolling element capable of rolling on a raceway surface of the first guide rail and a raceway surface of the second guide rail;
A linear guide device including a cage that holds the rolling elements,
The cage includes a first portion and a second portion that are mated together,
A linear guide device in which a notch is formed in a joint surface of at least one of the first part and the second part, thereby providing the cage with a lubricant pocket that contacts the rolling surfaces of the rolling elements.
The linear guide device according to claim 1, characterized in that the lubricant pocket is provided on the outer surface of the retainer when the first part and the second part are combined.
At least one of the first part and the second part has an elastically deformable engagement part that engages with the other of the first part and the second part,
3. The linear guide device according to claim 1, wherein the lubricant pocket is provided around the engaging portion.