Actuator

Abstract

An electric hydraulic cylinder 100A comprises: a hydraulic cylinder 40 as a cylinder part; a unit U which is disposed in parallel with the hydraulic cylinder 40 and which serves as a drive part for driving the hydraulic cylinder 40; and a pressure sensor 31 and a stroke sensor 32 which are disposed between the hydraulic cylinder 40 and the unit U and which serve as state sensors for detecting the state of the electric hydraulic cylinder 100A.

Description

Actuator

[0001] The present invention relates to an actuator.

[0002] JP2016-56658A discloses an electric hydraulic cylinder in which a detector for detecting the operating state has a detection rod attached to the piston rod and a limit switch attached to the cylindrical part of the cylinder that operates in accordance with the movement of the detection rod.JP3-304A 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.

[0003] In the invention described in JP2016-56658A, a detector for detecting the operating state is provided protruding from the electric hydraulic cylinder, and in the invention described in JP3-304A, an encoder for detecting the operating state is provided protruding from the electric hydraulic actuator. Therefore, when attempting to replace an 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.

[0004] The present invention has been made in view of the above-mentioned problems, and has an object to install a status sensor while suppressing an increase in size.

[0005] According to one aspect of the present invention, there is provided an actuator comprising a cylinder section and a drive section arranged in parallel with the cylinder section to drive the cylinder section, the actuator having a status sensor arranged between the cylinder section and the drive section to detect the status of the actuator.

[0006] Fig. 1 is a side view of an electric hydraulic cylinder according to an embodiment of the present invention. Fig. 2 is a front view of an electric hydraulic cylinder according to an embodiment of the present invention. Fig. 3 is an external view of a connecting member. Fig. 4 is an explanatory diagram of an area in which a status sensor is disposed. Fig. 5 is a diagram showing a modified example of a stroke detection plate. Fig. 6 is a diagram showing a modified example of an electric hydraulic cylinder. Fig. 7 is a side view of an electric cylinder according to an embodiment of the present invention.

[0007] 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.

[0008] The electric hydraulic cylinder 100A is an electric fluid pressure actuator (fluid pressure actuator) that integrally comprises an electric motor 10 that rotates using 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 from the tank 60, a hydraulic cylinder 40 that expands and contracts using 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.

[0009] The electric motor 10 is an electric motor that generates power by receiving a supply of electric power, and its rotation is controlled by, for example, PWM control using 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 depending on the rotation direction of the electric motor 10, and the discharge direction can be selectively switched depending on the rotation.

[0010] 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 circumferential surface of the cylinder tube 41.

[0011] 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 / retraction 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 a male threaded fixing portion 42bb is fastened to the tip of the rod main body 42a.

[0012] The piston 43 divides the interior of the cylinder tube 41 into a bottom-side chamber 44 and a rod-side chamber 45. These bottom-side chamber 44 and rod-side chamber 45 are filled with hydraulic oil. In the hydraulic cylinder 40, hydraulic oil is supplied to the bottom-side chamber 44 and discharged from the rod-side chamber 45, causing the piston rod 42 to move in the extension direction (to the right in FIG. 1 ). Furthermore, hydraulic oil is supplied to the rod-side chamber 45 and discharged from the bottom-side chamber 44, causing the piston rod 42 to move in the contraction direction (to the left in FIG. 1 ). In this way, the hydraulic cylinder 40 is a double-acting cylinder that moves the piston rod 42 back and forth using hydraulic oil discharged from the gear pump 20.

[0013] The hydraulic circuit 50 includes a housing 50a and a hydraulic circuit main body (not shown) that has an operable check valve, a slow return valve, and the like provided within 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 stores hydraulic oil by accumulating pressure using compressed gas. However, the tank 60 may also store hydraulic oil without accumulating pressure.

[0014] The electric motor 10, gear pump 20, hydraulic circuit 50, and tank 60 constitute a single unit U. The unit U is provided adjacent to the hydraulic cylinder 40, thereby making the electric hydraulic cylinder 100A compact. 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 arranged in parallel with the hydraulic cylinder 40 and constitutes a drive unit that drives the hydraulic cylinder 40, as well as a working fluid supply source that supplies and discharges working oil to and from the hydraulic cylinder 40.

[0015] 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 arranged between the hydraulic cylinder 40 and the unit U and connects the hydraulic cylinder 40 to the unit U.

[0016] The pressure sensor 31 and the stroke sensor 32 are both 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 protruding significantly from the electric hydraulic cylinder 100A in the width direction (left-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, the size of the electric hydraulic cylinder 100A is prevented from increasing. This prevents the pressure sensor 31 and the stroke sensor 32 from interfering with surrounding components when replacing the electric hydraulic cylinder 100A with an actuator that does not have status sensors such as the pressure sensor 31 and the stroke sensor 32, helping to ensure compatibility.

[0017] Furthermore, by disposing the pressure sensor 31 between the hydraulic cylinder 40 and the unit U, the pressure sensor 31 can be disposed in a position where it is easy to detect the pressure of the hydraulic oil supplied to or discharged from the hydraulic cylinder 40. Therefore, while the pressure sensor 31 is disposed in a position suitable for detection, it is possible to suppress an increase in the size of the electric hydraulic cylinder 100A.

[0018] 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.

[0019] 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. Using a non-contact sensor for the stroke sensor 32 prevents wires for stroke detection and the like from interfering with the installation of the electric hydraulic cylinder 100A.

[0020] The stroke sensor 32 emits laser light 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 received as reflected light by the stroke sensor 32. The stroke sensor 32 calculates the distance to the stroke detection plate 34A based on the emitted light and the reflected light, and detects (measures) changes in the calculated distance as the displacement of the piston rod 42. The stroke detection plate 34A is the part to be detected by the stroke sensor 32 and has a reflecting surface 34a that reflects the laser light from the stroke sensor 32. The reflecting surface 34a is positioned so as to be perpendicular to the laser light from the stroke sensor 32 and to cover the irradiation range of the laser light.

[0021] 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 with the tip inserted into the insertion hole, the fixing portion 42bb of the rod head 42b is fastened to the tip of the rod main body 42a, thereby fastening the stroke detection plate 34A to the rod main body 42a.

[0022] The stroke detection plate 34A may be composed of two divided plates having fixing portions that are fixed to the rod main body 42a with the rod main body 42a sandwiched between them. The fixing portions may be, for example, arc-shaped. In this case, the stroke detection plate 34A can be fixed to the rod main body 42a by fixing the two divided plates together with adhesive or the like with the rod main body 42a sandwiched between the fixing portions.

[0023] The connecting member 33 is installed by fixing the flange portion 41a and the housing 50a of the hydraulic circuit 50 while being 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 of the width direction of the electric hydraulic cylinder 100A and is fixed to the flange portion 41a with multiple (four in this example) bolts 35. The multiple 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 connecting member 33 described below, into bolt holes formed in the wall portions 50aa. This connects the hydraulic cylinder 40 and the unit U via the connecting member 33. In other words, the connecting member 33 installed in this manner can be considered an intervening connecting 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 at the bottom side of the cylinder tube 41 rather than at the center of the cylinder tube 41 in the extension / retraction direction of the hydraulic cylinder 40. The connecting member 33 is configured as follows.

[0024] Fig. 3 is an external view of the connecting member 33. Fig. 3 shows the connecting member 33 with the side that connects to the hydraulic cylinder 40 facing upward. The connecting member 33 has a generally flat plate shape and includes a connecting portion 331 that connects the hydraulic cylinder 40 and the unit U, and a sensor mounting portion 332 to which the pressure sensor 31 is attached.

[0025] The connecting portion 331 is formed thinner than the sensor mounting portion 332. The connecting portion 331 is formed thinner on the side that connects to the hydraulic cylinder 40. As a result, even if the connecting member 33 is provided, an increase in size of the electric hydraulic cylinder 100A 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, is suppressed.

[0026] 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.

[0027] The bolt insertion holes 33a are provided at the four corners of the connecting 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 connecting portion 331. The first oil passage 33b and the second oil passage 33c have larger diameters on the side connected to the hydraulic cylinder 40. The first oil passage 33b is connected to a connection port (not shown) that communicates 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) that communicates with a rod side chamber 45 of the hydraulic cylinder 40.

[0028] The sensor mounting portion 332 is connected 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 ) to the connection portion 331. The sensor mounting portion 332 is formed with a first installation portion 33d that communicates with the first oil passage 33b through a first communication passage 33f, and a second installation portion 33e that communicates with the second oil passage 33c through a second communication passage 33g.

[0029] The first mounting portion 33d and the second mounting portion 33e are both threaded holes, and a 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 sensors 31 in the first mounting portion 33d and the second mounting portion 33e, the pressure sensors 31 are directly fixed to the connecting member 33, and thus are provided to the connecting member 33 without going through the hydraulic cylinder 40 and the unit U.

[0030] 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 connecting member 33 is not formed uniformly thin as a whole, but the connecting portion 331 is formed thinner than the sensor mounting portion 332. Therefore, the thickness of the sensor mounting portion 332 required for mounting the pressure sensor 31 is ensured while suppressing an increase in the size of the electric hydraulic cylinder 100A in the parallel direction.

[0031] The sensor mounting portion 332 further includes a recess 332a formed in a concave shape along the extension / retraction direction of the electric hydraulic cylinder 100A in the widthwise center portion of the electric hydraulic cylinder 100A. The recess 332a has a shape that follows the outer periphery of the cylinder tube 41 and is formed by cutting the sensor mounting portion 332 into a trapezoidal shape. The recess 332a may be, for example, arc-shaped. 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 connecting member 33 can be positioned closer to the hydraulic cylinder 40, which also suppresses the expansion of the size of the electric hydraulic cylinder 100A in the parallel direction.

[0032] 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 or 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.

[0033] 4 is an explanatory diagram of region R in which the pressure sensor 31 and stroke sensor 32 serving as status sensors are disposed. Region R is an area sandwiched between the hydraulic cylinder 40 and unit U, and includes the area sandwiched between the hydraulic cylinder 40 and the tank 60 of unit U as shown in FIG. 4, as well as the area 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 area in which the connecting member 33 is disposed also constitutes part of region R.

[0034] 4, the pressure sensor 31 and the stroke sensor 32 provided on the connecting member 33 are disposed closer to 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 / retraction 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.

[0035] 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 into a unit beforehand and then attached to the electric hydraulic cylinder 100A. This facilitates installation of the pressure sensor 31 and the stroke sensor 32, as both are provided when the connecting member 33 is installed. The stroke sensor 32 may be fixed to the connecting member 33 via a support member such as a bracket, and thereby be integrally configured with the connecting member 33 together with the support member.

[0036] 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 while being 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 entire sensor is disposed outside the region R.

[0037] The stroke detection plate 34A may be configured as follows.

[0038] FIG. 5 shows a stroke detection plate 34B, a variation of the stroke detection plate 34A. The stroke detection plate 34B is attached to the main body 42ba of the rod head 42b. The stroke detection plate 34B is composed of a plate having a thickness roughly equivalent to that of the main body 42ba and protruding in a triangular shape from the main body 42ba. The side of the stroke detection plate 34B facing the stroke sensor 32 is the reflective surface 34b. Like the reflective surface 34a, the reflective surface 34b is positioned perpendicular to the laser light from the stroke sensor 32 and to cover the irradiation range of the laser light. The stroke detection plate 34B is fixed to the rod head 42b by adhesive. The stroke detection plate 34B may be integrally formed with the rod head 42b. The stroke detection plate 34B attached to the rod head 42b can also be used to detect the displacement of the piston rod 42 using the stroke sensor 32.

[0039] The stroke sensor 32 may be arranged as follows:

[0040] Figure 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 Figure 6, when viewed along the extension / retraction 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 Figure 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 that it can cover the irradiation range of the laser light from the stroke sensor 32 arranged in this manner.

[0041] In this example, the stroke sensor 32 is mounted on the housing 50a of the hydraulic circuit 50 via a bracket (not shown) and is not directly fixed to the connecting member 33. However, even when the stroke sensor 32 is provided in this manner, by disposing the stroke sensor 32 between the unit U and the hydraulic cylinder 40, it is possible to suppress the electric hydraulic cylinder 100B from overhanging in the width direction. Note that, although the stroke sensor 32 is disposed vertically (vertically in FIG. 6 ), it may also be disposed horizontally (horizontally 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 connecting member 33.

[0042] The actuator according to the embodiment of the present invention may be an electric actuator.

[0043] 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 uses the power from the electric motor 70 to extend or retract the length of a portion of a rod 94 that protrudes from a cylinder 92.

[0044] The electric motor 70 is an electric motor that is provided adjacent to the cylinder portion 90 and extends in the extension / retraction direction of the cylinder portion 90 (the left-right direction in FIG. 7 ). The electric motor 70 is arranged 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 / retraction direction of the electric cylinder 200.

[0045] The power transmission unit 80 has a speed reduction mechanism (not shown) that reduces the speed of input rotation from the electric motor 70 and outputs the reduced speed to the cylinder unit 90, and transmits power via the speed reduction mechanism. The speed reduction mechanism transmits power between the rotating shaft of the electric motor 70 provided at one end of the power transmission unit 80 and the ball screw 91 of the cylinder unit 90 provided at the other end of the power transmission unit 80 in the parallel direction of the electric cylinder 200 (the up and down direction in FIG. 7 ).

[0046] The cylinder unit 90 includes a ball screw 91 to which power is transmitted from the electric motor 70 via the power transmission unit 80; a cylinder 92 into which the ball screw 91 is rotatably inserted from its base end (right side in FIG. 7 ); a nut 93 movably mounted on the ball screw 91 along the axial direction within the cylinder 92 and threadedly engaged with the ball screw 91; and a rod 94 movably inserted into the cylinder 92 from its tip end (left side in FIG. 7 ) along the axial direction 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 portion of the ball screw 91 further distally (left side in FIG. 7 ) than 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 end to form an integral part.

[0047] When the electric motor 70 rotates in one direction and the ball screw 91 rotates in one direction accordingly, 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 increases. Conversely, when the electric motor 70 rotates in the other direction and the ball screw 91 rotates in the other direction accordingly, 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 decreases.

[0048] 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 in the axial direction within the cylinder 92. The cylinder portion 90 as the axially movable mechanism also constitutes a rod extension / contraction mechanism that extends and contracts 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 that has a rack provided so as to be movable in the axial direction within the cylinder 92, and a pinion that meshes with the rack.

[0049] 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.

[0050] The configuration, operation, and effects of the embodiment of the present invention will be described below.

[0051] The electric hydraulic cylinders 100A, 100B include a hydraulic cylinder 40 as a cylinder unit, a unit U as a drive unit arranged in parallel to the hydraulic cylinder 40 and driving the hydraulic cylinder 40, and a pressure sensor 31 and a stroke sensor 32 as status sensors that detect the status of the electric hydraulic cylinders 100A, 100B and are arranged between the hydraulic cylinder 40 and the unit U. The electric cylinder 200 also includes a cylinder unit 90, an electric motor 70 as a drive unit arranged in parallel to the cylinder unit 90 and driving the cylinder unit 90, and a temperature sensor 36 as a status sensor that detects the status of the electric cylinder 200 and is arranged between the cylinder unit 90 and the electric motor 70.

[0052] 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, which prevents the pressure sensor 31 and the stroke sensor 32 from protruding significantly from the electric hydraulic cylinders 100A, 100B. Therefore, even if the pressure sensor 31 and the stroke sensor 32 are disposed, an increase in the size of the electric hydraulic cylinders 100A, 100B can be prevented. Similarly, according to the electric cylinder 200 having this configuration, the temperature sensor 36 is disposed between the cylinder section 90 and the electric motor 70, which prevents the temperature sensor 36 from protruding significantly from the electric cylinder 200. Therefore, even if the temperature sensor 36 is disposed, an increase in the size of the electric cylinder 200 can be prevented.

[0053] 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. 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 provided as a state sensor.

[0054] According to this configuration, by arranging the pressure sensor 31 as the status sensor, the pressure sensor 31 can be arranged in a position where it is easy to detect the pressure of the hydraulic oil supplied to or discharged from the hydraulic cylinder 40. In other words, if the status sensor is the pressure sensor 31, it is possible to prevent the size of the electric hydraulic cylinder 100A from increasing while still installing the sensor in a position suitable for detection. The same applies to the electric hydraulic cylinder 100B.

[0055] 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. The hydraulic cylinder 40 and the unit U constitute an electric hydraulic cylinder 100A that is a fluid pressure actuator. A stroke sensor 32 that detects the stroke amount of the piston rod 42 of the hydraulic cylinder 40 is provided as a state sensor.

[0056] 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 in 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 prevent the electric hydraulic cylinder 100A from increasing in size while still installing the sensor in a position suitable for detection. The same applies to the electric hydraulic cylinder 100B.

[0057] 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 status sensors, a pressure sensor 31 that detects the pressure of the hydraulic oil supplied to and discharged from 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 connecting member 33 that is arranged between the hydraulic cylinder 40 and the unit U and connects the hydraulic cylinder 40 and the unit U.

[0058] According to this configuration, when viewed along the extension / retraction direction of the hydraulic cylinder 40, the pressure sensor 31 and the stroke sensor 32 can be arranged 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 arranged in positions suitable for detection, while suitably suppressing their protrusion in the width direction.

[0059] The pressure sensor 31 and the stroke sensor 32 are integrally formed with the connecting member 33 .

[0060] According to this configuration, the pressure sensor 31 and the stroke sensor 32, which are located close to each other and suitable for detection, are integrated with the connecting member 33 to form a unit, which makes it easy to install the pressure sensor 31 and the stroke sensor 32.

[0061] 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 that is arranged to be movable along the axial direction within the cylinder 92, and the electric motor 70, which serves as a drive section, is an electric motor that drives the cylinder section 90, and the cylinder section 90 and the rod 94 constitute the electric cylinder 200, which is an electric actuator.

[0062] According to this configuration, even in an electric cylinder 200 as an electric actuator in which an axially movable mechanism having a cylinder 92, such as a rod extension / retraction mechanism using a ball screw 91, is driven by an electric motor 70, a temperature sensor 36, which is an example of a status sensor, can be installed while suppressing size expansion.

[0063] Although the embodiments of the present invention have been described above, the above embodiments merely illustrate 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 embodiments.

[0064] This application claims priority based on Japanese Patent Application No. 2023-138014, filed with the Japan Patent Office on August 28, 2023, the entire contents of which are incorporated herein by reference.

Claims

1. An actuator comprising a cylinder section and a drive section arranged in parallel with the cylinder section and driving the cylinder section, the actuator having a status sensor arranged between the cylinder section and the drive section for detecting a status of the actuator.

2. An actuator as claimed in claim 1, wherein the cylinder section is a fluid pressure cylinder, the drive section is a working fluid supply source which supplies and discharges working fluid to the fluid pressure cylinder, the cylinder section and the drive section constitute a fluid pressure actuator, and the status sensor is a pressure sensor which detects the pressure of the working fluid supplied to and discharged from the fluid pressure cylinder.

3. An actuator as claimed in claim 1, wherein the cylinder section is a fluid pressure cylinder, the drive section is a working fluid supply source which supplies and discharges working fluid to the fluid pressure cylinder, the cylinder section and the drive section constitute a fluid pressure actuator, and the state sensor is a stroke sensor which detects the stroke amount of a piston rod of the fluid pressure cylinder.

4. An actuator as claimed in claim 1, wherein the cylinder section is a fluid pressure cylinder, the drive section is a working fluid supply source which supplies and discharges working fluid to the fluid pressure cylinder, the cylinder section and the drive section constitute a fluid pressure actuator, and the state 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, the pressure sensor and the stroke sensor being 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.

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

6. An actuator as described in claim 1, wherein 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.

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