Actuator

Abstract

To install a state sensor while suppressing enlargement in size.SOLUTION: An electric hydraulic cylinder 100A includes: a hydraulic cylinder 40 serving as a cylinder part; a unit U disposed in parallel with the hydraulic cylinder 40 to drive the hydraulic cylinder 40 as a drive part; and a pressure sensor 31 and a stroke sensor 32 disposed between the hydraulic cylinder 40 and the unit U to detect a state of the electric hydraulic cylinder 100A as a state sensor.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to an actuator. [Background technology]

[0002] Patent Document 1 discloses an electric hydraulic cylinder in which a detector for detecting an operating state includes a detection rod attached to the piston rod and a limit switch that is attached to the cylindrical portion of the cylinder and operates in accordance with the movement of the detection rod. Patent Document 2 discloses an electric hydraulic actuator in which an encoder is attached to the housing to measure the position of an operating rod attached to the piston. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2016-56658 A [Patent Document 2] Japanese Patent Application Publication No. 3-304 Summary of the Invention [Problem to be solved by the invention]

[0004] In the invention described in the cited document 1, a detector for detecting the operating state is provided protruding from the electric hydraulic cylinder, while in the invention described in the cited document 2, an encoder for detecting the operating state is provided protruding from the electric hydraulic actuator. Therefore, when replacing the actuator with one that does not have a detector for detecting the operating state, there is a risk that the detector will interfere with surrounding components, making it difficult to ensure compatibility.

[0005] The present invention has been made in consideration of such problems, and has an object to install a status sensor while suppressing an increase in size. [Means for solving the problem]

[0006] The present invention is an actuator comprising a cylinder section and a drive section arranged in parallel with the cylinder section and driving the cylinder section, characterized in that the actuator has a status sensor arranged between the cylinder section and the drive section for detecting the status of the actuator.

[0007] According to this invention, since the status sensor is disposed between the cylinder portion and the drive portion, the status sensor can be prevented from protruding significantly from the actuator. Therefore, even if the status sensor is provided, an increase in the size of the actuator can be prevented.

[0008] The present invention is also characterized in that the cylinder portion is a fluid pressure cylinder, the drive portion is a working fluid supply source that supplies and discharges working fluid to the fluid pressure cylinder, the cylinder portion and the drive portion constitute a fluid pressure actuator, and the status sensor is a pressure sensor that detects the pressure of the working fluid supplied to and discharged from the fluid pressure cylinder.

[0009] According to this invention, by arranging the pressure sensor as the status sensor, the pressure sensor can be arranged at a position where it is easy to detect the pressure of the working fluid supplied to and discharged from the fluid pressure cylinder. In other words, if the status sensor is a pressure sensor, it is possible to suppress an increase in the size of the actuator while installing the sensor at a position suitable for detection.

[0010] The present invention is also characterized in that the cylinder portion is a fluid pressure cylinder, the drive portion is a working fluid supply source that supplies and discharges working fluid to the fluid pressure cylinder, the cylinder portion and the drive portion constitute a fluid pressure actuator, and the status sensor is a stroke sensor that detects the stroke amount of a piston rod of the fluid pressure cylinder.

[0011] According to this invention, by disposing a stroke sensor as the status sensor, the stroke sensor can be disposed adjacent to the fluid pressure cylinder at a position where the stroke amount of the piston rod can be easily detected. In other words, if the status sensor is a stroke sensor, the sensor can be disposed at a position suitable for detection while suppressing an increase in the size of the actuator.

[0012] The present invention is also characterized in that the cylinder portion is a fluid pressure cylinder, the drive portion is a working fluid supply source which supplies and discharges working fluid to the fluid pressure cylinder, the cylinder portion and the drive portion constitute a fluid pressure actuator, the status sensor includes a pressure sensor which detects the pressure of the working fluid supplied to and discharged from the fluid pressure cylinder, and a stroke sensor which detects the stroke amount of a piston rod of the fluid pressure cylinder, and the pressure sensor and the stroke sensor are disposed between the fluid pressure cylinder and the working fluid supply source and provided on a connecting member which connects the fluid pressure cylinder and the working fluid supply source.

[0013] According to this invention, when viewed along the extension / contraction direction of the fluid pressure cylinder, the pressure sensor and the stroke sensor can be disposed more centrally (at the center in the width direction, which is the direction perpendicular to the parallel direction in which the fluid pressure cylinder and the working fluid supply source are lined up) in the area sandwiched between the fluid pressure cylinder and the working fluid supply source. Therefore, the pressure sensor and the stroke sensor can be disposed in positions suitable for detection, while suitably suppressing protrusion in the width direction.

[0014] In addition, the present invention is characterized in that the pressure sensor and the stroke sensor are integrally formed with the connecting member.

[0015] According to this invention, the pressure sensor and the stroke sensor, whose positions suitable for detection are close to each other, are integrated with the connecting member to form a unit, which makes it easy to install the pressure sensor and the stroke sensor.

[0016] The present invention is also characterized in that the cylinder portion is an axially movable mechanism having a cylinder and a movable portion arranged to be movable along the axial direction within the cylinder, the drive portion is an electric motor that drives the axially movable mechanism, and the cylinder portion and the drive portion constitute an electric actuator.

[0017] According to this invention, even in an electric actuator in which an axially movable mechanism having a cylinder is driven by an electric motor, such as a rod extension mechanism using a ball screw, a status sensor can be installed while suppressing an increase in size. Effect of the Invention

[0018] According to these inventions, the status sensor can be installed while suppressing an increase in size. [Brief description of the drawings]

[0019] [Figure 1] FIG. 1 is a side view of an electric hydraulic cylinder according to an embodiment of the present invention. [Diagram 2] FIG. 1 is a front view of an electric hydraulic cylinder according to an embodiment of the present invention. [Diagram 3] FIG. [Figure 4] FIG. 4 is an explanatory diagram of an area in which a status sensor is arranged. [Diagram 5] 13A and 13B are diagrams illustrating modified examples of the stroke detection plate. [Figure 6] FIG. 13 is a diagram showing a modified example of the electric hydraulic cylinder. [Figure 7] FIG. 1 is a side view of an electric cylinder according to an embodiment of the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0020] First, the overall configuration of an actuator according to an embodiment of the present invention will be described with reference to Figures 1 and 2. In the following, an electric hydraulic cylinder 100A that uses hydraulic oil as a working fluid will be described as an example.

[0021] The electric hydraulic cylinder 100A is an electric fluid pressure actuator (fluid pressure actuator) that integrally comprises an electric motor 10 that rotates by electricity, a tank 60 that stores hydraulic oil, a gear pump 20 that is driven by the rotation of the electric motor 10 and discharges the hydraulic oil sucked in from the tank 60, a hydraulic cylinder 40 that expands and contracts due to the hydraulic pressure of the hydraulic oil discharged from the gear pump 20, and a hydraulic circuit 50 that controls the flow of hydraulic oil flowing between the hydraulic cylinder 40 and the gear pump 20.

[0022] The electric motor 10 is an electric motor that generates power by receiving a supply of electric power, and the rotation is controlled by, for example, PWM control by an inverter. The gear pump 20 is connected to a rotating shaft (not shown) of the electric motor 10 and is driven by the rotation of the rotating shaft. The gear pump 20 rotates in both directions according to the rotation direction of the electric motor 10, and the discharge direction is selectively switched according to the rotation.

[0023] The hydraulic cylinder 40 is a fluid pressure cylinder and corresponds to a cylinder section. The hydraulic cylinder 40 includes a cylindrical cylinder tube 41, a piston rod 42 inserted into the cylinder tube 41 from one end side of the cylinder tube 41, and a piston 43 provided at the end of the piston rod 42 and sliding along the inner peripheral surface of the cylinder tube 41.

[0024] A flange portion 41a, which is a fixed portion to a unit U described later, is provided on the outer periphery of the cylinder tube 41. The flange portion 41a is provided at the center of the cylinder tube 41 in the extension / contraction direction of the hydraulic cylinder 40. The piston rod 42 has a rod main body 42a and a rod head 42b fixed to the tip of the rod main body 42a. The rod head 42b is a tip fitting (tip connecting portion) of the piston rod 42, and has a main body portion 42ba and a fixing portion 42bb. A female thread (not shown) is formed at the tip of the rod main body 42a, and the fixing portion 42bb, which is formed with a male thread, is screwed into the tip of the rod main body 42a.

[0025] The piston 43 divides the inside of the cylinder tube 41 into a bottom side chamber 44 and a rod side chamber 45. The bottom side chamber 44 and the rod side chamber 45 are filled with hydraulic oil. In the hydraulic cylinder 40, the piston rod 42 moves in the extension direction (rightward in FIG. 1) as the hydraulic oil is supplied to the bottom side chamber 44 and discharged from the rod side chamber 45. Meanwhile, the piston rod 42 moves in the contraction direction (leftward in FIG. 1) as the hydraulic oil is supplied to the rod side chamber 45 and discharged from the bottom side chamber 44. In this way, the hydraulic cylinder 40 is a double-acting cylinder that moves the piston rod 42 back and forth by the hydraulic oil discharged from the gear pump 20.

[0026] The hydraulic circuit 50 includes a housing 50a and a hydraulic circuit body (not shown) having an operate check valve, a slow return valve, and the like provided in the housing 50a, and controls the flow of hydraulic oil between the hydraulic cylinder 40 and the gear pump 20. The hydraulic circuit 50 is connected to a tank 60 via a tank passage (not shown). The tank 60 is an accumulator that accumulates and stores hydraulic oil by compressed gas. However, the tank 60 may also store hydraulic oil without accumulating pressure.

[0027] The electric motor 10, the gear pump 20, the hydraulic circuit 50, and the tank 60 constitute a single unit U. The unit U is provided adjacent to the hydraulic cylinder 40, thereby forming a compact electric hydraulic cylinder 100A. The unit U extends along the extension / retraction direction of the hydraulic cylinder 40. The extension / retraction direction of the hydraulic cylinder 40 is the same as the extension / retraction direction of the electric hydraulic cylinder 100A. The unit U is disposed in parallel with the hydraulic cylinder 40 and constitutes a drive unit that drives the hydraulic cylinder 40, and also constitutes a working fluid supply source that supplies and discharges working oil to and from the hydraulic cylinder 40.

[0028] The electric hydraulic cylinder 100A further includes a pressure sensor 31 that detects the pressure of the hydraulic oil supplied to and discharged from the hydraulic cylinder 40, a stroke sensor 32 that detects the stroke amount of the piston rod 42 of the hydraulic cylinder 40, and a connecting member 33 that is disposed between the hydraulic cylinder 40 and the unit U and connects the hydraulic cylinder 40 to the unit U.

[0029] Both the pressure sensor 31 and the stroke sensor 32 are status sensors that detect the status of the electric hydraulic cylinder 100A, and are disposed between the hydraulic cylinder 40 and the unit U. This prevents the pressure sensor 31 and the stroke sensor 32 from significantly protruding from the electric hydraulic cylinder 100A in the width direction (left and right direction in FIG. 2) of the electric hydraulic cylinder 100A. Therefore, even if the pressure sensor 31 and the stroke sensor 32 are installed, an increase in the size of the electric hydraulic cylinder 100A is prevented. This prevents the pressure sensor 31 and the stroke sensor 32 from interfering with surrounding components when replacing an actuator that does not have status sensors such as the pressure sensor 31 and the stroke sensor 32, which helps ensure compatibility.

[0030] Furthermore, by disposing the pressure sensor 31 between the hydraulic cylinder 40 and the unit U, the pressure sensor 31 can be disposed at a position where it is easy to detect the pressure of the hydraulic oil supplied to and discharged from the hydraulic cylinder 40. Therefore, while the pressure sensor 31 is disposed at a position suitable for detection, it is possible to suppress an increase in the size of the electric hydraulic cylinder 100A.

[0031] Similarly, by disposing the stroke sensor 32 between the hydraulic cylinder 40 and the unit U, the stroke sensor 32 can be disposed adjacent to the hydraulic cylinder 40 at a position where it is easy to detect the stroke amount of the piston rod 42. Therefore, while the stroke sensor 32 is disposed at a position suitable for detection, it is possible to suppress an increase in the size of the electric hydraulic cylinder 100A.

[0032] The stroke sensor 32 is a sensor capable of measuring the displacement of the piston rod 42, and is configured as a non-contact sensor by being configured with a laser displacement meter. The stroke sensor 32 as a non-contact sensor may be a sensor that detects the displacement of the piston rod 42 by using waves other than laser light, such as millimeter waves or ultrasonic waves. By using a non-contact sensor for the stroke sensor 32, wires for stroke detection and the like are prevented from interfering with the installation of the electric hydraulic cylinder 100A.

[0033] The stroke sensor 32 irradiates a laser beam in the extension / contraction direction of the electric hydraulic cylinder 100A, which is the displacement direction of the piston rod 42. The light emitted from the stroke sensor 32 is reflected by a stroke detection plate 34A provided on the piston rod 42, and is received by the stroke sensor 32 as reflected light. The stroke sensor 32 calculates the distance to the stroke detection plate 34A based on the emitted light and the reflected light, and a change in the calculated distance is detected (measured) as the displacement of the piston rod 42. The stroke detection plate 34A is a detection target of the stroke sensor 32, and has a reflection surface 34a for the laser beam from the stroke sensor 32. The reflection surface 34a is disposed so as to be perpendicular to the laser beam from the stroke sensor 32 and to cover the irradiation range of the laser beam.

[0034] The stroke detection plate 34A is fixed to the rod main body 42a. The stroke detection plate 34A has an insertion hole (not shown) through which the tip of the rod main body 42a is inserted, and is fastened to the rod main body 42a by fastening the fixing part 42bb of the rod head 42b to the tip of the rod main body 42a with the tip inserted into the insertion hole.

[0035] The stroke detection plate 34A may be composed of two divided plates having fixing parts that are fixed to the rod main body 42a with the rod main body 42a sandwiched between them. The fixing parts are, for example, arc-shaped, and in this case, the stroke detection plate 34A can be fixed to the rod main body 42a by fixing the two divided plates together by adhesive or the like with the rod main body 42a sandwiched between the fixing parts.

[0036] The connection member 33 is installed by fixing the flange portion 41a and the housing 50a of the hydraulic circuit 50 in a state where it is sandwiched between the flange portion 41a and the hydraulic circuit 50. The housing 50a has wall portions 50aa protruding in a frame shape on both sides in the width direction of the electric hydraulic cylinder 100A, and is fixed to the flange portion 41a by a plurality of (four here) bolts 35. The plurality of bolts 35 are fastened to bolt holes formed in the wall portions 50aa through bolt insertion holes formed in the flange portion 41a and bolt insertion holes 33a (see FIG. 3) of the connection member 33 described later. As a result, the hydraulic cylinder 40 and the unit U are connected via the connection member 33. In other words, the connection member 33 installed in this way can be said to be a connection intermediary member that intervenes in the connection between the hydraulic cylinder 40 and the unit U. The connection position between the hydraulic cylinder 40 and the unit U may be on the bottom side of the cylinder tube 41, not the center of the cylinder tube 41, in the extension and contraction direction of the hydraulic cylinder 40. The connection member 33 is configured as follows.

[0037] Fig. 3 is an external view of the connection member 33. Fig. 3 shows the connection member 33 with the side connected to the hydraulic cylinder 40 facing upward. The connection member 33 has a generally flat plate shape and includes a connection part 331 that connects the hydraulic cylinder 40 and the unit U, and a sensor attachment part 332 to which the pressure sensor 31 is attached.

[0038] The connection portion 331 is formed thinner than the sensor attachment portion 332. The connection portion 331 is formed thinner on the side connected to the hydraulic cylinder 40. This prevents the size of the electric hydraulic cylinder 100A from increasing in the parallel direction (the vertical direction in FIGS. 1 and 2), which is the direction in which the unit U and the hydraulic cylinder 40 are aligned, even if the connection member 33 is provided.

[0039] The connecting portion 331 is formed with a bolt insertion hole 33a through which the bolt 35 is inserted, and a first oil passage 33b and a second oil passage 33c which are oil passages for the hydraulic oil supplied and discharged between the hydraulic cylinder 40 and the unit U. Therefore, the connecting member 33 also serves as an oil passage member in which the oil passages for the hydraulic oil supplied and discharged between the hydraulic cylinder 40 and the unit U are formed.

[0040] The bolt insertion holes 33a are provided at the four corners of the connection portion 331. The first oil passage 33b and the second oil passage 33c are formed side by side in the width direction of the electric hydraulic cylinder 100A in the center of the connection portion 331. The first oil passage 33b and the second oil passage 33c are enlarged in diameter on the side connected to the hydraulic cylinder 40. The first oil passage 33b is connected to a connection port (not shown) communicating with a bottom side chamber 44 of the hydraulic cylinder 40, and the second oil passage 33c is connected to a connection port (not shown) communicating with a rod side chamber 45 of the hydraulic cylinder 40.

[0041] The sensor mounting portion 332 is connected to the connection portion 331 from the base end side in the extension / retraction direction of the electric hydraulic cylinder 100A (the right side in the left-right direction in FIG. 1). The sensor mounting portion 332 is formed with a first installation portion 33d that communicates with the first oil passage 33b through the first communication passage 33f, and a second installation portion 33e that communicates with the second oil passage 33c through the second communication passage 33g.

[0042] The first mounting portion 33d and the second mounting portion 33e are both screw holes, and the pressure sensor 31 is screwed into each of the first mounting portion 33d and the second mounting portion 33e. Therefore, a total of two pressure sensors 31 are provided corresponding to the bottom side chamber 44 and the rod side chamber 45. The pressure sensor 31 provided in the first mounting portion 33d is used to detect the hydraulic pressure of the hydraulic oil in the bottom side chamber 44, and the pressure sensor 31 provided in the second mounting portion 33e is used to detect the hydraulic pressure of the hydraulic oil in the rod side chamber 45. By providing the pressure sensor 31 in the first mounting portion 33d and the second mounting portion 33e, the pressure sensor 31 is directly fixed to the connecting member 33, and thus the pressure sensor 31 is provided in the connecting member 33 without passing through the hydraulic cylinder 40 and the unit U.

[0043] The first installation portion 33d and the second installation portion 33e are formed on a side surface 33h on the base end side in the extension / retraction direction of the electric hydraulic cylinder 100A. The connection member 33 is not formed uniformly thin as a whole, but the connection portion 331 is formed thinner than the sensor attachment portion 332. Therefore, the thickness of the sensor attachment portion 332 required for attaching the pressure sensor 31 is ensured while suppressing the size expansion in the parallel direction of the electric hydraulic cylinder 100A.

[0044] The sensor mounting portion 332 further has a recess 332a formed in a concave shape along the extension / contraction direction of the electric hydraulic cylinder 100A in the center of the width direction of the electric hydraulic cylinder 100A. The recess 332a has a shape along the outer periphery of the cylinder tube 41, and is formed by cutting the sensor mounting portion 332 into a trapezoid shape. The recess 332a may be, for example, an arc shape. By providing the recess 332a, the sensor mounting portion 332 is less likely to interfere with the hydraulic cylinder 40 compared to when the recess 332a is not provided. Therefore, compared to when the recess 332a is not provided, the connection member 33 can be arranged closer to the hydraulic cylinder 40, which also suppresses the size expansion in the parallel direction of the electric hydraulic cylinder 100A.

[0045] The connecting member 33 is further provided with a stroke sensor 32. The stroke sensor 32 is provided on a side surface 33i on the tip side in the extension / retraction direction of the electric hydraulic cylinder 100A. The stroke sensor 32 is fixed to the side surface 33i by adhesive. As a result, the stroke sensor 32 is directly fixed to the connecting member 33, and is provided on the connecting member 33 without going through the hydraulic cylinder 40 and the unit U. By providing the pressure sensor 31 and the stroke sensor 32 on the connecting member 33, the pressure sensor 31 and the stroke sensor 32 are arranged as follows.

[0046] 4 is an explanatory diagram of region R in which the pressure sensor 31 and stroke sensor 32 serving as state sensors are disposed. Region R is a region sandwiched between the hydraulic cylinder 40 and unit U, and includes, as shown in FIG. 4, a region sandwiched between the hydraulic cylinder 40 and the tank 60 of unit U, as well as a region sandwiched between the hydraulic cylinder 40 and the electric motor 10, gear pump 20, and hydraulic circuit 50 (see FIG. 1) of unit U. The region in which the connection member 33 is disposed also constitutes a part of region R.

[0047] 4, the pressure sensor 31 and the stroke sensor 32 provided on the connection member 33 are disposed in the center (the widthwise center of the electric hydraulic cylinder 100A) of the region R sandwiched between the hydraulic cylinder 40 and the unit U when viewed along the extension and contraction direction of the electric hydraulic cylinder 100A. Therefore, the pressure sensor 31 and the stroke sensor 32 are disposed in positions suitable for detection, while the protrusion of the electric hydraulic cylinder 100A in the widthwise direction is suitably suppressed.

[0048] The pressure sensor 31 and the stroke sensor 32 are integrally configured with the connecting member 33 and form a single component. That is, the connecting member 33, the pressure sensor 31, and the stroke sensor 32 are assembled to the electric hydraulic cylinder 100A in a pre-unitized state. This makes it easy to install the pressure sensor 31 and the stroke sensor 32, since both are provided when the connecting member 33 is provided. The stroke sensor 32 may be fixed to the connecting member 33 via a support member such as a bracket, and thus be integrally configured with the connecting member 33 together with the support member.

[0049] The pressure sensor 31 and the stroke sensor 32, which are disposed between the unit U and the hydraulic cylinder 40, are both disposed within the region R. It is preferable that the pressure sensor 31 and the stroke sensor 32 are disposed entirely within the region R when disposed between the unit U and the hydraulic cylinder 40, but a portion of them may protrude outside the region R. Even in this case, the size increase is suppressed compared to when the entirety is disposed outside the region R.

[0050] The stroke detection plate 34A may be configured as follows.

[0051] FIG. 5 is a diagram showing a stroke detection plate 34B, which is a modified example of the stroke detection plate 34A. The stroke detection plate 34B is provided on the main body 42ba of the rod head 42b. The stroke detection plate 34B is made of a plate having a thickness approximately equal to that of the main body 42ba, and protrudes from the main body 42ba in a triangular shape. In the stroke detection plate 34B, the side surface facing the stroke sensor 32 is the reflection surface 34b. The reflection surface 34b is arranged so as to be perpendicular to the laser light from the stroke sensor 32 and cover the irradiation range of the laser light, similar to the reflection surface 34a. The stroke detection plate 34B is fixed to the rod head 42b by adhesion. The stroke detection plate 34B may be formed integrally with the rod head 42b. The stroke detection plate 34B provided on the rod head 42b can also be used for detecting the displacement of the piston rod 42 by the stroke sensor 32.

[0052] The stroke sensor 32 may be arranged as follows:

[0053] Fig. 6 is a diagram showing an electric hydraulic cylinder 100B which is a modified example of the electric hydraulic cylinder 100A. The electric hydraulic cylinder 100B differs from the electric hydraulic cylinder 100A in the arrangement of the stroke sensor 32. In this example, as shown in Fig. 6, when viewed along the extension and contraction direction of the electric hydraulic cylinder 100B, the stroke sensor 32 is arranged between the unit U and the hydraulic cylinder 40 at a position closer to one side (the right side in Fig. 6) than the center in the width direction of the electric hydraulic cylinder 100B. The stroke detection plate 34C is formed slightly larger than the stroke detection plate 34A so as to cover the irradiation range of the laser light from the stroke sensor 32 arranged in this manner.

[0054] In this example, the stroke sensor 32 is provided in the housing 50a of the hydraulic circuit 50 via a bracket (not shown), and is not directly fixed to the connection member 33. On the other hand, even when the stroke sensor 32 is provided in this manner, the stroke sensor 32 is disposed between the unit U and the hydraulic cylinder 40, thereby suppressing the protrusion in the width direction of the electric hydraulic cylinder 100B. Note that, although the stroke sensor 32 is disposed vertically in this example (up and down direction in FIG. 6), it may be disposed horizontally in (left and right direction in FIG. 6). The pressure sensor 31, when disposed between the unit U and the hydraulic cylinder 40, does not necessarily have to be directly fixed to the connection member 33.

[0055] The actuator according to the embodiment of the present invention may be an electric actuator.

[0056] 7 is a side view of an electric actuator, an electric cylinder 200. The electric cylinder 200 has an electric motor 70, a power transmission unit 80 that transmits power from the electric motor 70 to a cylinder unit 90, and the cylinder unit 90 that extends or retracts the length of a rod 94 that protrudes from a cylinder 92 by the power from the electric motor 70.

[0057] The electric motor 70 is an electric motor that is provided adjacent to the cylinder portion 90 and extends along the extension and retraction direction of the cylinder portion 90 (left and right direction in FIG. 7). The electric motor 70 is disposed in parallel with the cylinder portion 90 and constitutes a drive portion that drives the cylinder portion 90. The electric motor 70 and the cylinder portion 90 are connected to the power transmission portion 80 from the same side (the left side in FIG. 7) in the extension and retraction direction of the electric cylinder 200.

[0058] The power transmission unit 80 has a speed reduction mechanism (not shown) that reduces the speed of the input rotation from the electric motor 70 and outputs it to the cylinder unit 90, and performs power transmission by this speed reduction mechanism. The speed reduction mechanism transmits power between a rotating shaft of the electric motor 70 provided on one end side of the power transmission unit 80 and a ball screw 91 of the cylinder unit 90 provided on the other end side of the power transmission unit 80 in the parallel direction of the electric cylinder 200 (the vertical direction in FIG. 7).

[0059] The cylinder section 90 includes a ball screw 91 to which power is transmitted from the electric motor 70 via the power transmission section 80, a cylinder 92 into which the ball screw 91 is rotatably inserted from the base end side (right side in FIG. 7), a nut 93 movably provided on the ball screw 91 along the axial direction in the cylinder 92 and screwed with the ball screw 91, and a rod 94 movably inserted into the cylinder 92 along the axial direction from the tip side (left side in FIG. 7) and connected to the nut 93. The rod 94 includes a rod body 94a and a rod head 94b provided at the tip of the rod body 94a. The ball screw 91 is rotatably supported via a bearing (not shown), and the part of the ball screw 91 on the tip side (left side in FIG. 7) beyond the nut 93 is rotatably inserted into the cylindrical rod body 94a. A trapezoidal screw or the like may be used instead of the ball screw 91. The rod head 94b is inserted into the rod body 94a from the tip side to be integrated.

[0060] When the electric motor 70 rotates in one direction and the ball screw 91 rotates in one direction in response, the nut 93 moves together with the rod 94 toward the tip end along the axial direction. As a result, the length of the portion of the rod 94 protruding from the cylinder 92 becomes longer. Conversely, when the electric motor 70 rotates in the other direction and the ball screw 91 rotates in the other direction in response, the nut 93 moves together with the rod 94 toward the base end along the axial direction. As a result, the length of the portion of the rod 94 protruding from the cylinder 92 becomes shorter.

[0061] The cylinder portion 90 constitutes an axially movable mechanism having a cylinder 92 and a rod 94 that is a movable portion provided so as to be movable along the axial direction within the cylinder 92. In addition, the cylinder portion 90 as the axially movable mechanism constitutes a rod extension mechanism that extends and retracts the length of the portion of the rod 94 that protrudes from the cylinder 92. The axially movable mechanism may be, for example, a rack-and-pinion mechanism having a rack provided so as to be movable along the axial direction within the cylinder 92, and a pinion that meshes with the rack.

[0062] The electric cylinder 200 is provided with a temperature sensor 36 that detects the temperature of the electric cylinder 200. The temperature sensor 36 is a status sensor, and is disposed between the electric motor 70 and the cylinder portion 90. In other words, by disposing the temperature sensor 36 between the electric motor 70 and the cylinder portion 90 in the electric cylinder 200 as well, it is possible to prevent the temperature sensor 36 from protruding significantly from the electric cylinder 200. The electric cylinder 200 may be provided with another status sensor instead of the temperature sensor 36.

[0063] The configuration, operation, and effects of the embodiment of the present invention will be described below.

[0064] The electric hydraulic cylinders 100A, 100B include a hydraulic cylinder 40 as a cylinder portion, a unit U arranged in parallel with the hydraulic cylinder 40 as a drive portion that drives the hydraulic cylinder 40, and a pressure sensor 31 and a stroke sensor 32 arranged between the hydraulic cylinder 40 and the unit U and serving as status sensors that detect the status of the electric hydraulic cylinders 100A, 100B. The electric cylinder 200 includes a cylinder portion 90, an electric motor 70 arranged in parallel with the cylinder portion 90 as a drive portion that drives the cylinder portion 90, and a temperature sensor 36 arranged between the cylinder portion 90 and the electric motor 70 and serving as a status sensor that detects the status of the electric cylinder 200.

[0065] According to the electric hydraulic cylinders 100A, 100B having this configuration, the pressure sensor 31 and the stroke sensor 32 are disposed between the hydraulic cylinder 40 and the unit U, so that the pressure sensor 31 and the stroke sensor 32 can be prevented from protruding significantly from the electric hydraulic cylinders 100A, 100B. Therefore, even if the pressure sensor 31 and the stroke sensor 32 are disposed, the size of the electric hydraulic cylinders 100A, 100B can be prevented from increasing. Similarly, according to the electric cylinder 200 having this configuration, the temperature sensor 36 is disposed between the cylinder portion 90 and the electric motor 70, so that the temperature sensor 36 can be prevented from protruding significantly from the electric cylinder 200. Therefore, even if the temperature sensor 36 is disposed, the size of the electric cylinder 200 can be prevented from increasing.

[0066] The hydraulic cylinder 40 as the cylinder section is a fluid pressure cylinder, and the unit U as the drive section is a hydraulic fluid supply source that supplies and discharges hydraulic oil to the hydraulic cylinder 40, and the hydraulic cylinder 40 and the unit U constitute an electric hydraulic cylinder 100A that is a fluid pressure actuator. A pressure sensor 31 that detects the pressure of the hydraulic oil supplied to and discharged from the hydraulic cylinder 40 is disposed as a state sensor.

[0067] According to this configuration, by arranging the pressure sensor 31 as the status sensor, the pressure sensor 31 can be arranged at a position where it is easy to detect the pressure of the hydraulic oil supplied to and discharged from the hydraulic cylinder 40. In other words, if the status sensor is the pressure sensor 31, it is possible to suppress an increase in the size of the electric hydraulic cylinder 100A while installing the sensor at a position suitable for detection. The same applies to the electric hydraulic cylinder 100B.

[0068] The hydraulic cylinder 40 as the cylinder section is a fluid pressure cylinder, and the unit U as the drive section is a hydraulic fluid supply source that supplies and discharges hydraulic oil to the hydraulic cylinder 40, and the hydraulic cylinder 40 and the unit U constitute an electric hydraulic cylinder 100A that is a fluid pressure actuator. As a state sensor, a stroke sensor 32 that detects the stroke amount of the piston rod 42 of the hydraulic cylinder 40 is provided.

[0069] According to this configuration, by arranging the stroke sensor 32 as the status sensor, the stroke sensor 32 can be arranged adjacent to the hydraulic cylinder 40 at a position where it is easy to detect the stroke amount of the piston rod 42. In other words, if the status sensor is the stroke sensor 32, it is possible to suppress an increase in the size of the electric hydraulic cylinder 100A while installing the sensor at a position suitable for detection. The same applies to the electric hydraulic cylinder 100B.

[0070] The hydraulic cylinder 40 as the cylinder section is a fluid pressure cylinder, and the unit U as the drive section is a hydraulic fluid supply source that supplies and discharges hydraulic oil to the hydraulic cylinder 40, and the hydraulic cylinder 40 and the unit U constitute an electric hydraulic cylinder 100A that is a fluid pressure actuator. As state sensors, a pressure sensor 31 that detects the pressure of the hydraulic oil supplied and discharged to the hydraulic cylinder 40 and a stroke sensor 32 that detects the stroke amount of a piston rod 42 of the hydraulic cylinder 40 are arranged, and the pressure sensor 31 and the stroke sensor 32 are provided on a connection member 33 that is arranged between the hydraulic cylinder 40 and the unit U and connects the hydraulic cylinder 40 and the unit U.

[0071] According to this configuration, when viewed along the extension / contraction direction of the hydraulic cylinder 40, the pressure sensor 31 and the stroke sensor 32 can be disposed more centrally (at the center in the width direction, which is the direction perpendicular to the parallel direction of the electric hydraulic cylinder 100A) in the region R sandwiched between the hydraulic cylinder 40 and the unit U. Therefore, the pressure sensor 31 and the stroke sensor 32 can be disposed in positions suitable for detection, while suitably suppressing protrusion in the width direction.

[0072] The pressure sensor 31 and the stroke sensor 32 are integrally formed with the connecting member 33 .

[0073] According to this configuration, the pressure sensor 31 and the stroke sensor 32, which are located close to each other in positions suitable for detection, are integrated with the connecting member 33 to form a unit, so that the pressure sensor 31 and the stroke sensor 32 can be easily installed.

[0074] In the electric cylinder 200, the cylinder section 90 is an axially movable mechanism having a cylinder 92 and a rod 94 which is a movable section arranged to be movable along the axial direction within the cylinder 92, and the electric motor 70 as a driving section is an electric motor which drives the cylinder section 90, and the cylinder section 90 and the rod 94 constitute the electric cylinder 200 which is an electric actuator.

[0075] According to this configuration, even in the electric actuator 200 that uses an electric motor 70 to drive an axially movable mechanism having a cylinder 92, such as a rod extension / retraction mechanism using a ball screw 91, a temperature sensor 36, which is an example of a condition sensor, can be installed while suppressing size increase.

[0076] Although the embodiments of the present invention have been described above, the above-mentioned embodiments merely show some of the application examples of the present invention, and it is not intended that the technical scope of the present invention be limited to the specific configurations of the above-mentioned embodiments. [Explanation of symbols]

[0077] 10···motor, 20···gear pump, 31···pressure sensor (status sensor), 32···stroke sensor (status sensor), 33···connecting member, 34A, 34B, 34C···stroke detection plate, 36···temperature sensor (status sensor), 40···hydraulic cylinder (cylinder portion), 50···hydraulic circuit, 60···tank, 70···electric motor (drive portion, electric motor), 90···cylinder portion (axially movable mechanism), 91···ball screw, 92···cylinder, 93···nut, 94···rod, 100A, 100B···electric hydraulic cylinder (actuator, fluid pressure actuator), 200···electric cylinder (actuator, electric actuator), R···area, U···unit (drive portion, working fluid supply source)

Claims

1. An actuator including a cylinder portion and a drive portion arranged in parallel with the cylinder portion and driving the cylinder portion, a state sensor disposed between the cylinder portion and the drive portion and detecting a state of the actuator; An actuator characterized by:

2. 2. The actuator of claim 1, the cylinder portion is a fluid pressure cylinder, the drive unit is a hydraulic fluid supply source that supplies and discharges hydraulic fluid to and from the fluid pressure cylinder, the cylinder portion and the drive portion constitute a fluid pressure actuator, The state sensor is a pressure sensor that detects the pressure of the working fluid supplied to and discharged from the fluid pressure cylinder. An actuator characterized by:

3. 2. The actuator of claim 1, the cylinder portion is a fluid pressure cylinder, the drive unit is a hydraulic fluid supply source that supplies and discharges hydraulic fluid to and from the fluid pressure cylinder, the cylinder portion and the drive portion constitute a fluid pressure actuator, The state sensor is a stroke sensor that detects a stroke amount of a piston rod of the fluid pressure cylinder. An actuator characterized by:

4. 2. The actuator of claim 1, the cylinder portion is a fluid pressure cylinder, the drive unit is a hydraulic fluid supply source that supplies and discharges hydraulic fluid to and from the fluid pressure cylinder, the cylinder portion and the drive portion constitute a fluid pressure actuator, the state sensor includes a pressure sensor that detects a pressure of a working fluid supplied to or discharged from the fluid pressure cylinder, and a stroke sensor that detects a stroke amount of a piston rod of the fluid pressure cylinder, the pressure sensor and the stroke sensor are disposed between the fluid pressure cylinder and the working fluid supply source, and are provided on a connection member that connects the fluid pressure cylinder and the working fluid supply source. An actuator characterized by:

5. 5. The actuator according to claim 4, The pressure sensor and the stroke sensor are integrally formed with the connecting member. An actuator characterized by:

6. 2. The actuator of claim 1, The cylinder portion is an axially movable mechanism having a cylinder and a movable portion provided so as to be movable along the axial direction within the cylinder, the driving unit is an electric motor that drives the axially movable mechanism, The cylinder unit and the drive unit constitute an electric actuator. An actuator characterized by:

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