JP5722365B2 - Linear actuator - Google Patents

Description

  The present invention relates to a linear actuator, and more particularly to a self-lubricating linear actuator.

  The linear drive system disclosed in Patent Document 1 is that the helical blade 61 is driven and rotated by the motor F, and at the same time, the lubricant is transported to the surface of the vertical axis 1 to produce a lubrication effect (reference numeral is Patent Document 1). The reference numerals in the description of the above are cited).

  However, in the invention described in Patent Document 1, the motor F continuously rotates the helical blade 61 and transports the lubricant to the surface of the vertical axis 1 regardless of whether or not the linear drive system operates. Therefore, there is a wasteful supply of lubricant and the cost is increased.

US Pat. No. 8,302,499

  The present invention has been made in view of the above problems, and the object thereof is to avoid wasteful supply of lubricant by injecting lubricant only during operation, and to effectively reduce costs. It is to provide a linear actuator.

  In order to solve the above-described problems, a linear actuator according to the present invention includes a shaft, a moving body, a plurality of balls, a lubrication mechanism, and a sensor. The moving body is mounted on the shaft so as to be linearly movable. The plurality of balls are movably mounted between the shaft and the moving body. The lubrication unit has a tank, a motor, a guide unit, and a controller. The tank has an oil storage space and an injection hole connected to the oil storage space. The oil storage space is used for storing lubricant and is connected to the surface of the shaft by an injection hole. The guide unit is mounted in the oil storage space of the tank and connected to the motor. The controller is electrically connected to the motor. The sensor is electrically connected to the controller of the lubrication unit, and intermittently transmits an operation signal to the controller as the moving body moves. As the moving body moves along the axial direction of the shaft, the sensor sends an activation signal to the controller. The controller controls the start of the motor based on the operation signal. At this time, the guide unit receives the driving force of the motor and guides the lubricant to the surface of the shaft through the injection hole. Thereby, lubrication can be performed automatically.

1 is a linear actuator according to a first embodiment of the present invention. It is a perspective view showing the state where the linear actuator by a 1st embodiment of the present invention was partially disassembled. It is sectional drawing which shows a part of linear actuator by 1st Embodiment of this invention. FIG. 4 is a cross-sectional view taken along line 4-4 in FIG. It is a control flowchart of the linear actuator by 1st Embodiment of this invention. It is a perspective view which shows the linear actuator by 2nd Embodiment of this invention. It is a perspective view which shows a part of linear actuator by 2nd Embodiment of this invention. It is a control flowchart of the linear actuator by 2nd Embodiment of this invention. It is sectional drawing which shows the linear actuator by 3rd Embodiment of this invention. It is a control flowchart of the linear actuator by 3rd Embodiment of this invention. It is a perspective view which shows the linear actuator by 4th Embodiment of this invention.

Hereinafter, a linear actuator according to an embodiment of the present invention will be described with reference to the drawings.
(First embodiment)
As shown in FIGS. 1, 2, and 4, the linear actuator 10 according to the first embodiment of the present invention includes a shaft 20, a moving body 30, a plurality of balls 40, a lubrication unit 50, and a sensor 60. In this embodiment, the linear actuator 10 is a ball screw, the shaft 20 is a screw, and the moving body 30 is a nut.

  The moving body 30 is attached to the shaft 20 so as to be rotatable, and can reciprocate along the axial direction of the shaft 20 and simultaneously form a circulation passage 42 between the moving body 30 and the shaft 20 as shown in FIG.

  The ball 40 is mounted in the circulation passage 42 and moves along the circulation passage 42 when the moving body 30 moves relative to the shaft 20.

  As shown in FIG. 4, the lubrication unit 50 includes a tank 51, a motor 52, a guide unit 53, and a controller 54.

  In the present embodiment, the tank 51 is attached to the shaft 20 and connected to the end face of the moving body 30. And an adjacent control room 57. The oil storage space 55 is used for storing lubricant and is divided into an oil chamber 552 and a sub oil chamber 554 by a first separator 58. The oil chamber 552 and the auxiliary oil chamber 554 are connected to each other. As shown in FIG. 2, the auxiliary oil chamber 554 is connected to the surface of the shaft 20 by the injection hole 556. The control chamber 57 is divided into a control groove 572 and a rolling groove 574 by the second separator plate 59, and has a rolling unit 62 in the rolling groove 574. The rolling unit 62 is a stainless ball. The motor 52 is fixed in the power chamber 56 of the tank 51 and has a drive shaft 522 that enters the auxiliary oil chamber 554.

  Since the guide unit 53 is connected to the drive shaft 522 of the motor 52 so as to be positioned in the auxiliary oil chamber 554 of the tank 51, the guide unit 53 can not only rotate by receiving the driving force of the motor 52 but also in the process of rotation. The lubricant can be guided from the oil chamber 554 to the surface of the shaft 20 through the injection hole 556. The controller 54 is fixed in the control groove 572 of the control chamber 57 of the tank 51 and is electrically connected to the motor 52 to control the start or stop of the motor 52.

  In this embodiment, the sensor 60 is like a switch, is fixed to the second separator 59 so as to be located in the control chamber 57 of the tank 51, and is electrically connected to the controller 54. The sensor 60 senses a change in the position of the rolling unit 62 and sends an operation signal to the controller 54 based on the sensed change in position.

  The following was found from the structure described above. As shown in FIG. 5, when the moving body 30 moves along the axial direction of the shaft 20, the lubrication unit 50 moves together with the moving body 30, and the rolling unit 62 rolls freely in the rolling groove 574. . At this time, the sensor 60 senses a change in the position of the rolling unit 62. When the sensor 60 senses the rolling unit 62, it sends an activation signal to the controller 54. Subsequently, the controller 54 activates the motor 52 based on the received operation signal. The guide unit 53 receives the driving force of the motor 52 and produces an effect of automatically performing lubrication by transporting the lubricant in the oil storage space 55 to the surface of the shaft 20 through the injection hole 556. On the other hand, if the sensor 60 does not detect the rolling unit 62, the transmission of the operation signal is interrupted. When the operation signal is interrupted, the controller 54 stops the operation of the motor 52, and the guide unit 53 stops the supply operation. Therefore, when the rolling unit 62 rolls continuously, that is, when the moving body 30 moves, the sensor 60 sends an intermittent operation signal to the controller 54, so that the controller 54 controls the lubrication unit 50. The refueling operation can be advanced.

(Second Embodiment)
A linear actuator according to a second embodiment of the present invention will be described with reference to FIGS. As shown in FIGS. 6 and 7, the safe position of the sensor 60 can be changed. In the second embodiment, the sensor 60 is embedded in the fixed hole 32 of the moving body 30. Since the fixing hole 32 is connected to the circulation passage 42 along the radial direction, the sensor 60 can detect a change in the position of the ball 40 in the circulation passage 42. The tank (not shown in the figure) is not a fixed system that is attached to the shaft 20 as in the above-described embodiment, but an external type is adopted according to the position of the sensor 60. More specifically, as shown in FIGS. 7 and 8, when one of the balls 40 passes the position facing the sensor 60 along the circulation path 42, the sensor 60 sends an operation signal to the controller 54. If the sensed ball 40 moves continuously along the circulation path 42 and passes the sensor, the sensor 60 can no longer sense the position of the ball 40 and interrupts the activation signal. When the next ball 40 passes the position facing the sensor 60, the sensor 60 transmits an operation signal again. Therefore, the present invention can intermittently send an operation signal to the controller 54.

(Third embodiment)
A linear actuator according to a third embodiment of the present invention will be described with reference to FIGS. The sensor 60 is not limited to a switch type. As shown in FIGS. 9 and 10, in the third embodiment, the sensor 60 is a vibration type sensor that senses the vibration of the tank 70 generated by moving with the moving body 30 and transmits an operation signal. Since the sensor 60 stops transmitting the operation signal when the tank 70 is stationary, the intermittent operation signal can be transmitted to the controller 54 as well. On the other hand, in this embodiment, the sensor 60 is fixed in the control chamber 72 of the tank 70 together with the controller 54. The control chamber 72 of the tank 70 does not need to divide different use spaces by the second separator 59 as in the first embodiment.

  As described above, in the linear actuator 10 according to the present invention, the controller 54 determines whether or not the moving body 30 moves based on the intermittent operation signal generated in the sensor 60. Since the lubrication unit 50 injects the lubricant only when the moving body 30 moves, compared to the prior art, the present invention reliably avoids waste and can effectively reduce the cost of the lubricant. .

(Fourth embodiment)
A linear actuator according to a fourth embodiment of the present invention will be described with reference to FIG. The linear actuator 10 according to the present embodiment is not limited to the ball screw used in the above-described embodiment, and a linear guide rail may be employed as shown in FIG. When a linear guide rail is employed, the shaft 20 is a guide rail, and the moving body 30 is a slide unit. If they are used in combination with the lubrication unit 50 and the sensor 60, the effect of automatically performing lubrication can be produced.

  As mentioned above, this invention is not limited to the said embodiment at all, In the range which does not deviate from the meaning of invention, it can implement with a various form.

10: Linear actuator
20: shaft,
30: Mobile object,
32: fixing hole,
40: Ball,
42: circulation passage,
50: Lubrication unit,
51, 70: Tank,
52: Motor,
522: drive shaft,
53: Guide unit,
54: Controller
55: Oil storage space,
552: oil chamber,
554: Secondary oil chamber,
556: injection hole,
56: Power room,
57, 72: control room,
572: control groove,
574: rolling groove,
58: first separator,
59: Second separator
60: sensor
62: Rolling unit.

Claims (1)

A shaft,
A moving body mounted on the shaft so as to be linearly movable;
A plurality of balls movably mounted between the shaft and the moving body;
A tank having an oil storage space used for storing a lubricant and an injection hole connected to the oil storage space, a motor, a guide unit mounted in the oil storage space of the tank, and electrically connected to the motor The oil storage space is connected to the surface of the shaft by the injection hole, and the guide unit is connected to the motor to receive the driving force of the motor through the injection hole. A lubrication unit for guiding the lubricant to the surface of the shaft;
A sensor that is electrically connected to the controller of the lubrication unit and intermittently transmits an operation signal to the controller as the movable body moves.
The tank has a power chamber and a control chamber adjacent to the oil storage space, is attached to the shaft, and is connected to an end surface of the moving body,
The power chamber is equipped with an internal motor.
The control room is equipped with the controller and rolling unit inside,
The sensor is fixed in the control chamber of the tank, detects a change in the position of the rolling unit when the moving body moves, and transmits an operation signal,
The linear actuator according to claim 1, wherein the controller activates the motor based on an operation signal of the sensor.

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