Linear actuator

Patent metadata

Field	Value
Publication number	US-9297415-B2
Application number	US-201414245766-A
Country	US
Kind code	B2
Filing date	Apr 4, 2014
Priority date	Apr 4, 2014
Publication date	Mar 29, 2016
Grant date	Mar 29, 2016

Abstract

A linear actuator includes a slide, a first half return member, a second half return member and a slide block. The first and second half return members are hollow frames and sleeved onto the rail. A circulation path can be formed when the first and second half return members and the slide block are assembled together, the second half return member is directly disposed in the first radial gap of the first half return member, and the slide block is directly disposed in the second radial gap of the second half return member. Furthermore, there is no level difference in the first and second return grooves of the two half return members, which will prevent noise caused during movement of the rolling elements, reduce impact of the rolling elements against the circulation path, and therefore extending the life of the linear actuator.

First claim

What is claimed is:

1. A linear actuator comprising:
an elongated rail extending along an axial direction, and including two rolling grooves at both sides thereof extending in the axial direction;
a first half return member being a hollow frame integrally formed with two opposite outer end portions and two opposite first return portions, each of the outer end portions including a first engaging slot, each of the first return portions being formed with a first return groove, the first half return member being slidably mounted on the rail in a manner that the rail is engaged in the first engaging slots;
a second half return member being a hollow frame integrally formed with two opposite inner end portions and two opposite second return portions, each of the inner end portions including two guiding protrusions each of which extends from a restricting surface of each of the inner end portions, each of the guiding protrusions including a guiding surface which is a partially circular surface, the inner end portions of the second half return member being connected to the guiding surfaces of the guiding protrusions and each of the inner end portions of the second half return member being formed with a second engaging slot, each of the second return portions including a second return groove extending along the axial direction and the second return groove being connected to two corresponding ones of the guiding surfaces, the second half return member being inserted between the two outer end portions of the first half return member, in a manner that the rail is inserted through the second engaging slots, the guiding surfaces of the guiding protrusions of the second half return member are connected to the first return grooves, the second return grooves are in communication with the first return grooves, the guiding surfaces are located toward the first return grooves, the first return grooves cooperate with the second return grooves, and the restricting surfaces of the second half return member to define a return path; and
a slide block with a top surface, two lateral portions, and an engaging slot defined between the two lateral portions and extending along the axial direction, two opposite rolling grooves extending along the axial direction being formed on the two lateral portions, the slide block being received between the two inner end portions of the second half return member, in a manner that the rail is inserted through the engaging slot of the slide block, the opposite rolling grooves of the slide block cooperate with the rolling grooves of the rail to define a load path which is connected to the guiding surfaces of the second half return member and is in communication with the return path, and the load path and the return path are connected to form an endless circulation path in which a plurality of rolling elements are able to move endlessly;
a direction perpendicular to the axial direction is defined as a radial direction, the two first return portions are closer to the axial direction than the two outer end portions, so as to define a first radial gap between the two outer portions and the two first return portions, on the outer surface of each of the first return portions is formed an abutting portion which is a stepped groove concaved from the first radial gap, another surface of each of the lateral portions of the slide block is formed an outer groove extending along the axial direction, between each of the outer grooves and the top surface is formed a covering portion extending in the radial direction, and the covering portions of the slide block are engaged with the abutting portions of the first half return member.

2. The linear actuator as claimed in claim 1 , wherein each of the first engaging slots includes two opposite arc-shaped protrusions which are formed on an inner surface thereof and are slidably received in the rolling grooves of the rail.

3. The linear actuator as claimed in claim 1 , wherein a plurality of positioning portions are formed on an inner surface of each of the two outer end portions, the two inner end portions each have an inner surface, and an outer surface, the inner surfaces of the two inner end portions are located opposite each other and located toward the second return portions, on the outer surface of each of the inner end portions is formed a plurality of restricting portions which are partially circular protrusions and shaped to fit in the positioning portions of the outer end portions.

4. The linear actuator as claimed in claim 1 , wherein each of the first return portions is formed with a positioning cavity which is located beside the first return grooves, and in the positioning cavity is formed a positioning gap, the guiding protrusions of the second half return member are engaged in the positioning cavities of the first half return member, the two lateral portions are inserted in the positioning gaps between the inner end portions and the second return portions of the second half return member, and the first half return member, the second half return member and the slide block are fixed together by a plurality of fasteners.

5. The linear actuator as claimed in claim 1 , wherein a direction perpendicular to the axial direction is defined as a radial direction, the two second return portions are closer to the axial direction than the two inner end portions, so as to define a second radial gap which opens in a direction different from a direction in which the second engaging slots open, the outer grooves are located toward the second radial gap and engaged with second return portions of the second half return member.

6. The linear actuator as claimed in claim 1 , wherein each of the first return grooves consists of a straight section extending along the axial direction, and two arc-shaped sections connected to two ends of the straight section, each of the guiding surfaces consists of an arc-shaped inner surface, an arc-shaped end surface and an arc-shaped outer surface which are sequentially connected to one another to form a partially circular surface, each of the second return portions includes an arc-shaped piece which is formed in the shape of the arc-shaped outer surface of the guiding protrusions, and the arc-shaped piece extends along the axial direction and is connected between the two inner end portions, each of the second return portions has the second return groove extending along the axial direction and connected to the arc-shaped outer surface, the arc-shaped inner surface of the inner end portions of the second half return member is connected to the arc-shaped inner surfaces of the guiding protrusions and formed with the second engaging slot, the restricting surfaces of the second half return member are located toward the arc-shaped sections of the first return grooves.

7. The linear actuator as claimed in claim 1 , wherein each of the first return grooves consists of a straight section extending along the axial direction, and two arc-shaped sections connected to two ends of the straight section, each of the guiding surfaces consists of an arc-shaped inner surface, an arc-shaped end surface and an arc-shaped outer surface which are sequentially connected to one another to form a partially circular surface, each of the second return portions includes an arc-shaped piece which is formed in the shape of the arc-shaped outer surface of the guiding protrusions, and the arc-shaped piece extends along the axial direction and is connected between the two inner end portions, each of the second return portions has the second return groove, the second return grooves are connected to the arc-shaped outer surfaces and the straight sections of the first return grooves, the arc-shaped inner surface of the inner end portions of the second half return member is c

Assignees

• Hiwin Tech Corp

Inventors

• Chu Yung-Chin

Classifications

• F16C29/0611 Primary

  of the return passages, i.e. the passages where the rolling elements do not carry load · CPC title

• F16C29/0657

  with two rows of balls, one on each side of the rail · CPC title