Steering device

Abstract

To provide a steering device capable of adjusting a sensor for steering angle detection before loading the steering device on a vessel.SOLUTION: A steering device 1A includes: a steering lever 2 fixed to a steering shaft 11; a ram 3 provided with a pin 31 engaging with the steering lever 2; and a pair of cylinders 4A, 4B into which both ends of the ram 3 are inserted. In addition, the steering device 1A includes: a bracket 7 for bridging the cylinders 4A, 4B to allow variation in distance between the cylinders 4A, 4B and a stroke sensor 8. The stroke sensor 8 includes a detection element 84 and a linear detector 81 extending in an axial direction of the ram 3 for detecting the position of the detection element 84. The detection element 84 is attached to one of the ram 3 and the bracket 7 and the linear detector 81 is attached to the other of the ram 3 and the bracket 7.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to a steering gear installed on a marine vessel. [Background technology]

[0002] Conventionally, a Rapson slide type steering gear including a ram and a pair of cylinders has been known. In such a steering gear, the steering angle is generally detected by a rotation angle sensor. For example, FIG. 2 of Patent Document 1 describes that the rotation angle sensor is disposed at a position away from the steering gear. Also, FIG. 2 of Patent Document 1 describes that the rudder and the rotation angle sensor are connected via a link mechanism so that the center of the rudder stock and the center of the rotation angle sensor are located at adjacent vertices of a parallelogram. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 3-99997 Summary of the Invention [Problem to be solved by the invention]

[0004] However, when detecting the rudder angle using a rotation angle sensor, the rotation angle sensor cannot be adjusted until the steering gear is installed on the ship. Moreover, the position of the rotation angle sensor needs to be geometrically adjusted on the ship, which is time-consuming.

[0005] Therefore, an object of the present disclosure is to provide a steering gear that allows adjustment of a sensor for detecting a rudder angle before the steering gear is installed on a vessel. [Means for solving the problem]

[0006] From a first aspect, the present disclosure provides a steering gear comprising: a rudder fixed to a rudder stock; a ram provided with a pin engaging with the rudder; a pair of cylinders into which both ends of the ram are inserted, respectively; a bracket bridging the pair of cylinders to allow for fluctuations in the distance between the pair of cylinders; and a stroke sensor including a detection element and a linear detector extending in the axial direction of the ram for detecting a position of the detection element, wherein the detection element is attached to one of the ram and the bracket, and the linear detector is attached to the other of the ram and the bracket.

[0007] From a second aspect, the present disclosure provides a steering gear comprising: a rudder fixed to a rudder stock; a ram provided with a pin engaging with the rudder; a pair of cylinders into which both ends of the ram are inserted; a guide bar parallel to the ram, the both ends of which are inserted into retaining holes provided in the pair of cylinders; a guide attached to the ram and engaging with the guide bar while sliding along the guide bar; and a stroke sensor including a detection element and a linear detector extending in the axial direction of the ram for detecting a position of the detection element, the detection element being attached to one of the guide and the guide bar, and the linear detector being attached to the other of the guide and the guide bar.

[0008] From a third aspect, the present disclosure provides a steering gear comprising: a rudder fixed to a rudder stock; a ram provided with a pin engaging with the rudder; a first cylinder and a second cylinder into which both ends of the ram are inserted, respectively; and a stroke sensor including a detection element and a linear detector extending in the axial direction of the ram for detecting the position of the detection element, wherein each of the first cylinder and the second cylinder includes a tubular portion and a bottom portion, the detection element is attached to one of the ram and the bottom portion of the first cylinder, and the linear detector is attached to the other of the ram and the bottom portion of the first cylinder. Effect of the Invention

[0009] According to the present disclosure, a steering gear is provided in which the sensor for detecting the rudder angle can be adjusted even before the steering gear is mounted on a vessel. [Brief description of the drawings]

[0010] [Figure 1] FIG. 2 is a plan view of the steering gear according to the first embodiment. [Diagram 2] FIG. 2 is a front view of the steering gear according to the first embodiment. [Diagram 3] FIG. 3 is a cross-sectional view taken along line III-III in FIG. [Figure 4] FIG. 4 is an enlarged cross-sectional view of the other end of the bracket. [Diagram 5] FIG. 11 is an enlarged cross-sectional view of the other end of the bracket in the modified example. [Figure 6] FIG. 11 is an enlarged cross-sectional view of the other end of the bracket in another modified example. [Figure 7] FIG. 11 is a plan view of a steering gear according to a second embodiment. [Figure 8] FIG. 11 is a front view of a steering gear according to a second embodiment. [Figure 9] FIG. 11 is a plan view of a steering gear according to a third embodiment. [Figure 10] FIG. 10 is a cross-sectional view taken along line XX in FIG. [Figure 11] FIG. 11 is a plan view of a steering gear according to a fourth embodiment. [Figure 12] FIG. 11 is a plan view of a steering gear according to another embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] First Embodiment 1 and 2 show a steering gear 1A according to the first embodiment. In this embodiment, the steering gear 1A includes a rudder 2 fixed to a rudder stock 11, and one hydraulic actuator 10 that swings the rudder 2. However, the steering gear 1A may include two hydraulic actuators 10 arranged parallel to each other with the rudder stock 11 in between.

[0012] The hydraulic actuator 10 includes a ram 3 and a pair of cylinders, a first cylinder 4A and a second cylinder 4B. Both ends of the ram 3 are inserted into the first cylinder 4A and the second cylinder 4B, respectively. For convenience of explanation, the first cylinder 4A side may be referred to as the left side and the second cylinder 4B side as the right side below, but there is no technical meaning to the left and right sides, and the first cylinder 4A side may be the right side and the second cylinder 4B side may be the left side.

[0013] 3, the rudder 2 includes a cylindrical part 21 into which the rudder stock 11 is inserted, and a pair of arms 22 protruding from the side of the cylindrical part 21. The arms 22 face each other in the vertical direction with the ram 3 in between, and these arms 22 are formed with engagement grooves 23 recessed from their tips.

[0014] A pin 31 is provided in the center of the ram 3 so as to vertically penetrate the ram 3. Rollers 32 are attached to the upper and lower parts of the pin 31, and the pin 31 engages with the engagement groove 23 of the tiller 2 via the rollers 32.

[0015] 1 and 2, each of the first cylinder 4A and the second cylinder 4B includes a tubular portion 41 that slides against the end of the ram 3, and a bottom portion 42 that faces the end face of the ram 3. Furthermore, a flange 43 is provided on the end of the tubular portion 41 opposite the bottom portion 42, i.e., the end on the pin 31 side.

[0016] In each of the first cylinder 4A and the second cylinder 4B, the space surrounded by the tubular portion 41, the bottom portion 42, and the end surface of the ram 3 constitutes an operating chamber. Hydraulic oil is supplied from a hydraulic pump to one of the operating chambers of the first cylinder 4A and the second cylinder 4B, and the hydraulic oil is discharged from the other.

[0017] Furthermore, the steering gear 1A includes a guide bar 5 parallel to the ram 3, and a guide 6 attached to the ram 3 and sliding along the guide bar 5 while engaging with the guide bar 5. The guide 6 serves to prevent the ram 3 from rotating. In this embodiment, the guide bar 5 is disposed on the opposite side of the ram 3 to the rudder stock 11.

[0018] The guide bar 5 has a circular cross section, with both ends having a smaller diameter. The flanges 43 of the first cylinder 4A and the second cylinder 4B described above are provided with retaining holes 44 penetrating the flanges 43 in the axial direction of the ram 3. Both ends of the guide bar 5 are inserted into these retaining holes 44.

[0019] The distance between the first cylinder 4A and the second cylinder 4B varies depending on the pressure in the working chambers of the first cylinder 4A and the second cylinder 4B. Since both ends of the guide bar 5 are simply fitted into the retaining holes 44, when the distance between the first cylinder 4A and the second cylinder 4B varies, at least one of the ends of the guide bar 5 slides against the retaining hole 44.

[0020] 3, the guide 6 has a guide groove that opens in a direction perpendicular to the axial direction of the ram 3 and the axial direction of the pin 31, and the guide bar 5 extends through this guide groove. Sliding plates 62 are attached above and below the guide bar 5 on the inner surface of the guide groove, and the guide 6 engages with the guide bar 5 via the sliding plates 62.

[0021] In this embodiment, the steering gear 1A includes a bracket 7 arranged on the opposite side of the guide bar 5 from the ram 3, and two stroke sensors 8 including a linear detector 81 attached to the bracket 7 and a detection element 84 attached to the guide 6. In other words, the detection element 84 is attached to the ram 3 via the guide 6. However, the number of stroke sensors 8 may be one.

[0022] The bracket 7 bridges the flange 43 of the first cylinder 4A and the flange 43 of the second cylinder 4B. More specifically, the bracket 7 includes a pair of horizontal bars 71 aligned vertically and parallel to the ram 3, and a pair of vertical bars 72 joined to both ends of the horizontal bars 71. In other words, the vertical bars 72 form one end and the other end of the bracket 7.

[0023] In this embodiment, each lateral bar 71 is an angle oriented in an inverted L-shape and includes a top plate and a front plate. A linear detector 81 is attached to the underside of the top plate of each lateral bar 71, so that the linear detector 81 is hidden from the front side of the steering gear 1A by the front plate of the lateral bar 71.

[0024] Furthermore, the bracket 7 is configured to allow for variation in the distance between the first cylinder 4A and the second cylinder 4B. In this embodiment, the left vertical bar 72, i.e., the left end of the bracket 7, is fixed to the flange 43 of the first cylinder 4A, and the right vertical bar 72, i.e., the right end of the bracket 7, is connected to the flange 43 of the second cylinder 4B so as to be slidable therewith. The vertical bar 72 is also an angle. The left vertical bar 72 may be fixed by bolts or welding.

[0025] The right-side vertical bar 72 includes a vertical plate to which the horizontal bar 71 is joined, and a horizontal plate that comes into surface contact with the end face of the flange 43. As shown in Fig. 4, the horizontal plate has a long slot 73 that is long in the axial direction of the ram 3, and the bolt 12 is fixed to the flange 43 through this slot 73. The bolt 12 is prevented from loosening from the flange 43. The bolt 12 is prevented from loosening by, for example, a locking agent or welding. Note that the bolt 12 is not shown in Figs. 1 and 2 to simplify the drawings.

[0026] A washer 13, through which the bolt 12 passes, abuts against the front surface of the horizontal plate of the right vertical bar 72. A compression coil spring 14 is disposed between the washer 13 and the head of the bolt 12, and the vertical bar 72 is pressed against the flange 43 by the biasing force of the spring 14. Therefore, when the distance between the first cylinder 4A and the second cylinder 4B changes, the vertical bar 72 slides against the flange 43. Note that instead of the bolt 12, a headed rod that is press-fitted into a fixing hole provided in the flange 43 may be used.

[0027] 1 and 2, the linear detector 81 of each stroke sensor 8 extends in the axial direction of the ram 3. The stroke sensor 8 is, for example, a magnetostrictive sensor, and the linear detector 81 detects the position of a detection element 84. The linear detector 81 includes a head 82 and a probe 83 extending from the head 82. In this embodiment, the probe 83 is rail-shaped, and the detection element 84 has a shape that engages with the rail. In the illustrated example, the head 82 is located to the left of the probe 83, but the head 82 may be located to the right of the probe 83.

[0028] The sensing element 84 of each stroke sensor 8 slides along the probe 83 of the linear detector 81. The sensing element 84 may or may not be in contact with the linear detector 81. The sensing element 84 is attached to the guide 6 via an L-shaped support 61.

[0029] As described above, in the steering gear 1A of this embodiment, the stroke sensor 8 can detect the relative position of the detection element 84 with respect to the linear detector 81 as the stroke of the ram 3, and the stroke of the ram 3 can be converted into a rudder angle. Moreover, since the detection element 84 and the linear detector 81 of the stroke sensor 8 are attached to the guide 6 and the bracket 7, the stroke sensor 8, which is a sensor for detecting the rudder angle, can be adjusted before the steering gear 1A is mounted on the ship.

[0030] Furthermore, the bracket 7 to which the linear detector 81 of the stroke sensor 8 is attached allows for variations in the distance between the first cylinder 4A and the second cylinder 4B, so that the stroke sensor 8 will not be damaged by variations in the distance between the first cylinder 4A and the second cylinder 4B.

[0031] <Modification> In the above embodiment, the linear detector 81 of the stroke sensor 8 is attached to the bracket 7, and the detection element 84 is attached to the ram 3 via the guide 6, but the opposite may also be true, where the linear detector 81 of the stroke sensor 8 is attached to the ram 3 via the guide 6, and the detection element 84 is attached to the bracket 7.

[0032] In addition, the structure for connecting the right end of the bracket 7 to the flange 43 of the second cylinder 4B so as to be slidable with respect to the flange 43 can be modified as appropriate. For example, as shown in FIG. 5, the spring 14 may be omitted and the vertical bar 72 may be pressed against the flange 43 by only the axial tension of the bolt 12.

[0033] Alternatively, the structure for connecting the right end of the bracket 7 to the flange 43 of the second cylinder 4B so as to be slidable with the flange 43 may be the structure shown in Fig. 6. In the structure shown in Fig. 6, a rod 76 protruding leftward is provided on the vertical plate of the right-side vertical bar 72, while a support plate 74 is provided on the right end of the horizontal bar 71, and a bush 75 that slides with the rod 76 is attached to the support plate 74.

[0034] The detection element 84 does not necessarily have to be attached to the ram 3 via the guide 6. For example, the detection element 84 may be attached to the ram 3 via a structure other than the guide 6, or may be attached directly to the ram 3. The same applies to the case where the linear detector 81 is attached to the ram 3.

[0035] <Second embodiment> 7 and 8 show a steering gear 1B according to a second embodiment. In this embodiment and in a third and fourth embodiment described later, the same components as those in the first embodiment are denoted by the same reference numerals, and duplicated explanations will be omitted.

[0036] In this embodiment, the bracket 7 is also configured to allow the distance between the first cylinder 4A and the second cylinder 4B to vary, but the specific structure is different from that of the first embodiment. In this embodiment, a mounting plate 77 is used instead of the right vertical bar 72, and the mounting plate 77 forms the right end of the bracket 7.

[0037] In this embodiment, the left vertical bar 72, i.e., the left end of the bracket 7, is fixed to the flange 43 of the first cylinder 4A, and the mounting plate 77, i.e., the right end of the bracket 7, is fixed to the flange 43 of the second cylinder 4B.

[0038] More specifically, the mounting plate 77 bends from the end face of the flange 43 of the second cylinder 4B and extends to the front of the lateral bar 71. The front plate of the lateral bar 71 is joined in surface contact with the portion of the mounting plate 77 located in front of the lateral bar 71. A part of the mounting plate 77 has a V-shaped cross section, and this portion constitutes an absorbing part that is elastically deformable in the axial direction of the ram 3.

[0039] Even with this configuration, the same effects as in the first embodiment can be obtained.

[0040] <Third embodiment> 9 and 10 show a steering gear 1C according to a third embodiment. In this embodiment, the number of stroke sensors 8 is one. In this embodiment, the length of the bracket 7 is set shorter than the distance between the first cylinder 4A and the second cylinder 4B, and the bracket 7 is attached to the guide bar 5. That is, the linear detector 81 of the stroke sensor 8 is attached to the guide bar 5 via the bracket 7. The detection element 84 of the stroke sensor 8 is attached to the guide 6 via the support 61, similar to the first embodiment.

[0041] In this embodiment, the bracket 7 includes one horizontal bar 71, and the attitude of the horizontal bar 71 is at an angle that differs by 90 degrees from that of the first embodiment. Specifically, the horizontal bar 71 has a top plate and a back plate, and a linear detector 81 is attached to the underside of the top plate, as in the first embodiment. Both ends of the back plate are fixed to the guide bar 5 via spacers 78.

[0042] In this embodiment, as in the first embodiment, the stroke sensor 8 can detect the relative position of the detection element 84 with respect to the linear detector 81 as the stroke of the ram 3, and the stroke of the ram 3 can be converted into a rudder angle. Moreover, since the detection element 84 and the linear detector 81 of the stroke sensor 8 are attached to the guide 6 and the guide bar 5, the stroke sensor 8, which is a sensor for detecting the rudder angle, can be adjusted before the steering gear 1C is mounted on the ship.

[0043] Furthermore, since the linear detector 81 of the stroke sensor 8 is attached to the guide bar 5 which is not affected by fluctuations in the distance between the first cylinder 4A and the second cylinder 4B, the stroke sensor 8 will not be damaged by fluctuations in the distance between the first cylinder 4A and the second cylinder 4B.

[0044] Contrary to this embodiment, the linear detector 81 of the stroke sensor 8 may be attached to the guide 6 and the detection element 84 may be attached to the guide bar 5.

[0045] <Fourth embodiment> 11 shows a steering gear 1D according to a fourth embodiment. In this embodiment, the linear detector 81 of the stroke sensor 8 is attached to the bottom 42 of the first cylinder 4A, and the detection element 84 is attached to the ram 3. For this reason, the bracket 7 is not used in this embodiment.

[0046] In this embodiment, the probe 83 of the linear detector 81 is rod-shaped, and the detection element 84 is ring-shaped and penetrates the rod. The ram 3 is provided with a hole 33 that opens into the left end face to avoid interference with the probe 83, and the detection element 84 is disposed in the hole 33 near the left end face of the ram 3.

[0047] In this embodiment, as in the first embodiment, the stroke sensor 8 can detect the relative position of the detection element 84 with respect to the linear detector 81 as the stroke of the ram 3, and the stroke of the ram 3 can be converted into a rudder angle. Moreover, since the detection element 84 and the linear detector 81 of the stroke sensor 8 are attached to the ram 3 and the bottom 42 of the first cylinder 4A, the stroke sensor 8, which is a sensor for detecting the rudder angle, can be adjusted before the steering gear 1C is mounted on the ship.

[0048] Furthermore, since the linear detector 81 of the stroke sensor 8 is attached to the bottom 42 of the first cylinder 4A, which is not affected by fluctuations in the distance between the first cylinder 4A and the second cylinder 4B, the stroke sensor 8 will not be damaged by fluctuations in the distance between the first cylinder 4A and the second cylinder 4B.

[0049] Contrary to this embodiment, the linear detector 81 of the stroke sensor 8 may be attached to the ram 3, and the detection element 84 may be attached to the bottom 42 of the first cylinder 4A.

[0050] <Other embodiments> The present disclosure is not limited to the above-described embodiments, and various modifications are possible without departing from the gist of the present disclosure.

[0051] 12, it is possible to provide a target 91 on the guide 6 and a displacement sensor 92 capable of measuring the displacement of the target 91 on the flange 43 of the first cylinder 4A or the second cylinder 4B. The displacement sensor 92 is, for example, a laser displacement meter or a wire potentiometer.

[0052] <Summary> In a first aspect, the present disclosure provides a steering gear comprising, from a first aspect, a rudder fixed to a rudder stock, a ram provided with a pin that engages with the rudder, a pair of cylinders into which both ends of the ram are inserted, a bracket bridging the pair of cylinders to allow for fluctuations in the distance between the pair of cylinders, and a stroke sensor including a detection element and a linear detector extending in the axial direction of the ram that detects the position of the detection element, wherein the detection element is attached to one of the ram and the bracket, and the linear detector is attached to the other of the ram and the bracket.

[0053] According to the above configuration, the stroke sensor can detect the relative position of the detection element with respect to the linear detector as the stroke of the ram, and the stroke of the ram can be converted into the rudder angle. Moreover, since the detection element and the linear detector of the stroke sensor are attached to the ram and the bracket, the stroke sensor, which is a sensor for detecting the rudder angle, can be adjusted before the steering gear is installed on the ship.

[0054] As a second aspect, in the first aspect, for example, the above steering gear further includes a guide bar parallel to the ram, the guide bar having both ends inserted into retaining holes provided in the pair of cylinders, and a guide attached to the ram and sliding along the guide bar while engaging with the guide bar, and the detection element or the linear detector may be attached to the ram via the guide.

[0055] As a third aspect, in the first or second aspect, for example, the pair of cylinders may be a first cylinder and a second cylinder, and one end of the bracket may be fixed to the first cylinder, and the other end of the bracket may be connected to the second cylinder so as to be slidable relative to the second cylinder.

[0056] As a fourth aspect, in the first or second aspect, for example, both ends of the bracket may be fixed to the pair of cylinders, and the bracket may have an absorbing portion that is elastically deformable in the axial direction of the ram.

[0057] As a fifth aspect, the present disclosure provides a steering gear from a second aspect, comprising: a rudder fixed to a rudder stock; a ram provided with a pin engaging with the rudder; a pair of cylinders into which both ends of the ram are inserted; a guide bar parallel to the ram, the both ends of which are inserted into retaining holes provided in the pair of cylinders; a guide attached to the ram and engaging with the guide bar while sliding along the guide bar; and a stroke sensor including a detection element and a linear detector extending in the axial direction of the ram to detect the position of the detection element, wherein the detection element is attached to one of the guide and the guide bar, and the linear detector is attached to the other of the guide and the guide bar.

[0058] According to the above configuration, the stroke sensor can detect the relative position of the detection element with respect to the linear detector as the ram stroke, and the ram stroke can be converted into the rudder angle. Moreover, since the detection element and the linear detector of the stroke sensor are attached to the guide and the guide bar, the stroke sensor, which is a sensor for detecting the rudder angle, can be adjusted before the steering gear is installed on the ship.

[0059] As a sixth aspect, from a third aspect, the present disclosure provides a steering gear comprising: a rudder fixed to a rudder stock; a ram provided with a pin engaging with the rudder; a first cylinder and a second cylinder into which both ends of the ram are inserted, respectively; a stroke sensor including a detection element and a linear detector extending in the axial direction of the ram for detecting the position of the detection element, wherein each of the first cylinder and the second cylinder includes a tubular portion and a bottom portion, the detection element is attached to one of the ram and the bottom portion of the first cylinder, and the linear detector is attached to the other of the ram and the bottom portion of the first cylinder.

[0060] According to the above configuration, the stroke sensor can detect the relative position of the detection element with respect to the linear detector as the ram stroke, and the ram stroke can be converted into the rudder angle. Moreover, since the detection element and linear detector of the stroke sensor are attached to the bottom of the ram and the first cylinder, the stroke sensor, which is a sensor for detecting the rudder angle, can be adjusted before the steering gear is installed on the ship. [Explanation of symbols]

[0061] 1A,1B,1C,1D,1E Steering gear 11 Rudder shaft 2 rudder handle 3. Ram 31 pin 4A First Cylinder 4B No. 2 cylinder 41 Tubular part 42 Bottom 44 Retaining hole 5 Guide bar 6 Guide 7 Bracket 8 Stroke Sensor 81 Linear Detector 84 Detector element

Claims

1. a rudder fixed to the rudder stock; a ram provided with a pin for engagement with the tiller; A pair of cylinders into which both ends of the ram are inserted, a bracket bridging the pair of cylinders to allow for variation in the distance between the pair of cylinders; a stroke sensor including a detection element and a linear detector extending in an axial direction of the ram for detecting a position of the detection element; The sensing element is attached to one of the ram and the bracket, and the linear detector is attached to the other of the ram and the bracket.

2. a guide bar parallel to the ram, the guide bar having both ends inserted into holding holes formed in the pair of cylinders; a guide attached to the ram and adapted to engage and slide along the guide bar, The steering gear according to claim 1 , wherein the detection element or the linear detector is attached to the ram via the guide.

3. the pair of cylinders being a first cylinder and a second cylinder, 3. The steering gear according to claim 1, wherein one end of the bracket is fixed to the first cylinder, and the other end of the bracket is connected to the second cylinder so as to be slidable with respect to the second cylinder.

4. 3. The steering gear according to claim 1, wherein both ends of the bracket are fixed to the pair of cylinders, and the bracket has an absorbing portion that is elastically deformable in the axial direction of the ram.

5. a rudder fixed to the rudder stock; a ram provided with a pin for engagement with the tiller; A pair of cylinders into which both ends of the ram are inserted, a guide bar parallel to the ram, the guide bar having both ends inserted into holding holes formed in the pair of cylinders; a guide attached to the ram and adapted to engage and slide along the guide bar; a stroke sensor including a detection element and a linear detector extending in an axial direction of the ram for detecting a position of the detection element; The steering gear, wherein the sensing element is attached to one of the guide and the guide bar, and the linear detector is attached to the other of the guide and the guide bar.

6. a rudder fixed to the rudder stock; a ram provided with a pin for engagement with the tiller; a first cylinder and a second cylinder into which both ends of the ram are inserted, respectively; a stroke sensor including a detection element and a linear detector extending in an axial direction of the ram for detecting a position of the detection element; each of the first cylinder and the second cylinder includes a tubular portion and a bottom portion; The sensing element is attached to one of the ram and the bottom of the first cylinder, and the linear detector is attached to the other of the ram and the bottom of the first cylinder.

Images