Fluid machine, rotation information calculation method, and construction machine

Abstract

The present application provides a fluid machine, a rotation information calculation method, and a construction machine. A hydraulic motor (1) of an embodiment includes a housing (2), a cylinder block (3), a valve plate (4), and pressure sensors (5a), (5b). The cylinder block (3) is housed in the housing (2) in a manner that is rotatable about a rotation axis (C), and has a cylinder chamber (9) into which working oil is supplied and discharged, and a cylinder port (10) that communicates with the cylinder chamber (9). The valve plate (4) is disposed between the housing (2) and the cylinder block (3) in the direction of the rotation axis (C), and is formed with a plurality of supply / discharge ports that communicate with the cylinder port (10) in a row around the rotation axis (C), and the valve plate (4) has a detection hole (20a) that is formed between adjacent supply / discharge ports around the rotation axis (C) and that communicates with the cylinder port (10). The pressure sensors (5a), (5b) detect the pressure of the working oil that flows into the detection hole (20a).

Description

Technical Field

[0001] This invention relates to fluid machinery, a method for calculating rotational information, and construction machinery. Background Technology

[0002] As fluid machinery, there exists a hydraulic motor used for driving construction mechanisms such as hydraulic excavators. A hydraulic motor comprises: a housing; a shaft rotatably supported within the housing; a cylinder body fitted and fixed to the outer circumference of the shaft, wherein multiple cylinder chambers are arranged in the direction of rotation to form the cylinder body; pistons housed in each cylinder chamber and capable of moving along the axis of rotation; and swashplates and valve plates housed within the housing and disposed on opposite sides of the cylinder body in the direction of rotation.

[0003] The piston end protrudes towards the swashplate and is connected to the swashplate by means of a sliding shoe that contacts the swashplate in a manner that allows it to slide relative to the swashplate. Each cylinder chamber is connected to the housing via a valve plate and a supply port and an exhaust port. The valve plate has a supply port and an exhaust port that connect the cylinder chamber to the supply port and the exhaust port.

[0004] Furthermore, by supplying working oil to the cylinder chamber through the supply port and valve plate, the piston is pressed against the ramp plate under the pressure of the working oil. At this time, the slipper slides relative to the ramp plate, converting the reaction force of the piston pressing against the ramp plate into a force in the rotational direction. As the cylinder and piston rotate as a unit, the piston repeatedly slides within the cylinder chamber (piston movement). During this time, the volume of the cylinder chamber changes, thereby discharging working oil from the outlet of the outer casing.

[0005] Existing technical documents

[0006] Patent documents

[0007] Patent Document 1: Japanese Utility Model Application Publication No. 63-120550 Summary of the Invention

[0008] The problem the invention aims to solve

[0009] However, fluid machinery such as hydraulic motors utilize fluids to generate rotational force, therefore, external rotation detection equipment is required to obtain rotational information of the shaft (cylinder). This increases the potential for complex construction of fluid machinery.

[0010] This invention provides a fluid machine capable of obtaining rotational information at low cost, a method for calculating rotational information, and construction machinery.

[0011] Solution for solving the problem

[0012] A fluid machine according to one embodiment of the present invention comprises: a housing; a cylinder body rotatably housed within the housing, having a cylinder chamber for supplying and discharging fluid and a cylinder port communicating with the cylinder chamber; a valve plate disposed between the housing and the cylinder body in the direction of the rotation axis, having a plurality of supply and discharge ports arranged around the rotation axis and communicating with the cylinder port, and the valve plate having a detection hole formed between adjacent supply and discharge ports around the rotation axis and communicating with the cylinder port; and a pressure extraction section for extracting the pressure of the fluid flowing into the detection hole.

[0013] With this configuration, fluid flows from the cylinder port into the detection port. The cylinder rotates relative to the valve plate with the detection port, repeatedly connecting or disconnecting the detection port from the cylinder port. This causes pressure pulsations in the fluid flowing into the detection port. By using a pressure extraction unit to capture the pressure waveform of the fluid resulting from these pulsations, and detecting the captured pressure waveform, rotational information such as the cylinder's rotational speed and angle can be obtained. Furthermore, since no external rotation detection equipment is required, the structure of the fluid machinery can be simplified.

[0014] In the above structure, the fluid machinery may also include a pressure detection unit installed on the pressure extraction unit for detecting the pressure of the fluid.

[0015] In the above structure, the fluid machinery may also include a piston disposed in the cylinder chamber in a manner that allows it to reciprocate freely along the axis of rotation, and the detection hole is formed in at least one of the valve plate, the piston at the top dead center position, and the piston at the bottom dead center position.

[0016] In the above structure, the outer casing may also have an extension hole communicating with the detection hole, and the pressure extraction part may extract the pressure of the detection hole through the extension hole.

[0017] In the above structure, the extended hole may also be formed on a straight line.

[0018] In the above structure, the housing may also be a rear flange having a supply and discharge port for supplying and discharging the fluid and communicating with the supply and discharge port.

[0019] In the above structure, the valve plate may also include: a piston receiving recess formed on a surface of the valve plate near the outer casing where the detection hole is formed; and a blocking piston housed in the piston receiving recess to block the opening of the piston receiving recess, forming a piston hole communicating with the detection hole.

[0020] In the above structure, the fluid machinery may also include a sealing portion that prevents the fluid from leaking between the inner side of the piston receiving recess and the outer side of the sealing piston.

[0021] In the above structure, the fluid machinery may also include a calculation unit that calculates the rotational speed of the cylinder based on the detection result of the pressure detection unit.

[0022] In the above structure, the detection hole may have at least a first detection hole and a second detection hole, and the pressure detection unit may have a first pressure detection unit and a second pressure detection unit. The first pressure detection unit outputs the detection result of the pressure of the fluid flowing into the first detection hole as a signal, and the second pressure detection unit outputs the detection result of the pressure of the fluid flowing into the second detection hole as a signal. The first detection hole and the second detection hole are formed in such a way that the output signal of the first pressure detection unit and the output signal of the second pressure detection unit have a phase difference.

[0023] In the above structure, the outer casing may also have a first extension hole communicating with the first detection hole and a second extension hole communicating with the second detection hole, the first pressure detection part being disposed on the side of the first extension hole opposite to the first detection hole, and the second pressure detection part being disposed on the side of the second extension hole opposite to the second detection hole.

[0024] In the above structure, the phase difference can also be any value between 10° and 170° or between 190° and 350°.

[0025] In the above structure, the phase difference can also be 90° or 270°.

[0026] In the above structure, the fluid machinery may also include a calculation unit that calculates the rotation direction of the cylinder based on the output signals of the first pressure detection unit and the second pressure detection unit.

[0027] In the above structure, the calculation unit may also include a counting calculation unit that counts the pulses of at least one of the output signals of the first pressure detection unit and the second pressure detection unit, and calculates the rotation angle of the cylinder based on the count value.

[0028] In the above structure, the calculation unit may also have a reset unit that resets the count value of the counting calculation unit when the rotation angle of the cylinder reaches a certain angle.

[0029] In the above structure, the calculation unit may also have a timer for measuring the time during which the pulses have been counted.

[0030] Another technical solution of the present invention provides a method for calculating rotational information of a fluid machine, the fluid machine comprising: a housing; a cylinder body rotatably housed within the housing, having a cylinder chamber for supplying and discharging fluid and a cylinder port communicating with the cylinder chamber; a valve plate disposed between the housing and the cylinder body in the direction of the rotational axis, having a plurality of supply and discharge ports arranged around the rotational axis and communicating with the cylinder port, and the valve plate having a first detection hole and a second detection hole formed between adjacent supply and discharge ports around the rotational axis and communicating with the cylinder port; a first pressure detection unit and a second pressure detection unit, the first... A pressure detection unit outputs a signal indicating the pressure of the fluid flowing into the first detection orifice, and a second pressure detection unit outputs a signal indicating the pressure of the fluid flowing into the second detection orifice; and a calculation unit calculates the rotation direction of the cylinder based on the output signals of the first and second pressure detection units, wherein the rotation information calculation method includes: a sequence detection step in which the calculation unit detects the rising sequence of the pulses of the output signals of the first and second pressure detection units; and a rotation direction determination step in which the rotation direction of the cylinder is determined based on the sequence detected in the sequence detection step.

[0031] By setting it in this way, the rotation direction, which serves as rotation information, can be easily determined using the output signals of the first pressure detection unit and the second pressure detection unit.

[0032] Another technical solution of the present invention provides a method for calculating rotational information of a fluid machine, the fluid machine comprising: a housing; a cylinder body rotatably housed within the housing, having a cylinder chamber for supplying and discharging fluid and a cylinder port communicating with the cylinder chamber; a valve plate disposed between the housing and the cylinder body in the direction of the rotational axis, having a plurality of supply and discharge ports arranged around the rotational axis and communicating with the cylinder port, and the valve plate having a first detection hole and a second detection hole formed between adjacent supply and discharge ports around the rotational axis and communicating with the cylinder port; a first pressure detection unit and a second pressure detection unit, the first... A pressure detection unit outputs a signal indicating the pressure of the fluid flowing into the first detection orifice, and a second pressure detection unit outputs a signal indicating the pressure of the fluid flowing into the second detection orifice; and a calculation unit calculates the rotation direction of the cylinder based on the output signals of the first and second pressure detection units, wherein the rotation information calculation method includes: a counting step in which the calculation unit counts pulses of at least one of the output signals of the first and second pressure detection units; and a rotation angle calculation step in which the rotation angle of the cylinder is calculated based on the count value of the counting step.

[0033] By setting it up in this way, the rotation angle, which is rotation information, can be easily calculated using the output signals of the first pressure detection unit and the second pressure detection unit.

[0034] Another technical solution of the present invention provides a method for calculating rotational information of a fluid machine, the fluid machine comprising: a housing; a cylinder body rotatably housed within the housing, having a cylinder chamber for supplying and discharging fluid and a cylinder port communicating with the cylinder chamber; a valve plate disposed between the housing and the cylinder body in the direction of the rotational axis, having a plurality of supply and discharge ports arranged around the rotational axis and communicating with the cylinder port, and the valve plate having a first detection hole and a second detection hole formed between adjacent supply and discharge ports around the rotational axis and communicating with the cylinder port; a first pressure detection unit and a second pressure detection unit, the first pressure detection unit outputting the detection result of the pressure of the fluid flowing into the first detection hole as a signal, and the second pressure detection unit outputting the pressure of the fluid flowing into the second detection hole as a signal. The method outputs the pressure detection result as a signal; and a calculation unit that calculates the rotation direction of the cylinder based on the output signals of the first pressure detection unit and the second pressure detection unit. The calculation unit includes: a counting calculation unit that counts the pulses of at least one of the output signals of the first pressure detection unit and the second pressure detection unit, and calculates the rotation angle of the cylinder based on the count value; and a timer that measures the time for counting the pulses. The rotation information calculation method includes: a frequency calculation step in which the calculation unit determines the frequency of at least one of the output signals of the first pressure detection unit and the second pressure detection unit; and a rotational speed calculation step in which the rotational speed of the cylinder is calculated based on the voltage value generated by performing an FV conversion on the frequency determined by the frequency calculation step.

[0035] By setting it up in this way, the rotational speed, which is the rotational information, can be easily calculated using the output signals of the first pressure detection unit and the second pressure detection unit.

[0036] Another technical solution of the present invention provides a method for calculating rotational information of a fluid machine, the fluid machine comprising: a housing; a cylinder body rotatably housed within the housing, having a cylinder chamber for supplying and discharging fluid and a cylinder port communicating with the cylinder chamber; a valve plate disposed between the housing and the cylinder body in the direction of the rotational axis, having a plurality of supply and discharge ports arranged around the rotational axis and communicating with the cylinder port, and the valve plate having a first detection hole and a second detection hole formed between adjacent supply and discharge ports around the rotational axis and communicating with the cylinder port; a first pressure detection unit and a second pressure detection unit, the first pressure detection unit outputting the detection result of the pressure of the fluid flowing into the first detection hole as a signal, and the second pressure detection unit outputting the pressure of the fluid flowing into the second detection hole as a signal. The pressure detection result of the inflowing fluid is output as a signal; and a calculation unit calculates the rotation direction of the cylinder based on the output signals of the first pressure detection unit and the second pressure detection unit, the calculation unit comprising: a counting calculation unit that counts the pulses of at least one of the output signals of the first pressure detection unit and the second pressure detection unit, and calculates the rotation angle of the cylinder based on the count value; and a timer for measuring the time during which the pulses are counted, wherein the rotation information calculation method comprises: a counting step in which the calculation unit counts the pulses of at least one of the output signals of the first pressure detection unit and the second pressure detection unit; and a rotational speed calculation step in which the rotational speed of the cylinder is calculated based on the count value of the counting step over a certain time period.

[0037] By setting it up in this way, the rotational speed, which is the rotational information, can be easily calculated using the output signals of the first pressure detection unit and the second pressure detection unit.

[0038] Another technical solution of the present invention provides a method for calculating rotational information of a fluid machine, the fluid machine comprising: a housing; a cylinder body rotatably housed within the housing, having a cylinder chamber for supplying and discharging fluid and a cylinder port communicating with the cylinder chamber; a valve plate disposed between the housing and the cylinder body in the direction of the rotational axis, having a plurality of supply and discharge ports arranged around the rotational axis and communicating with the cylinder port, and the valve plate having a first detection hole and a second detection hole formed between adjacent supply and discharge ports around the rotational axis and communicating with the cylinder port; a first pressure detection unit and a second pressure detection unit, the first pressure detection unit outputting the detection result of the pressure of the fluid flowing into the first detection hole as a signal, and the second pressure detection unit outputting the pressure of the fluid flowing into the second detection hole. The method outputs a signal based on the pressure detection result of the fluid; and a calculation unit that calculates the rotation direction of the cylinder based on the output signals of the first pressure detection unit and the second pressure detection unit. The calculation unit includes: a counting calculation unit that counts the pulses of at least one of the output signals of the first pressure detection unit and the second pressure detection unit, and calculates the rotation angle of the cylinder based on the count value; and a timer that measures the time for counting the pulses. The rotation information calculation method includes: a counting step in which the calculation unit counts the pulses of at least one of the output signals of the first pressure detection unit and the second pressure detection unit; and a rotational speed calculation step in which the rotational speed of the cylinder is calculated based on the time required to reach a certain count value in the counting step.

[0039] By setting it up in this way, the rotational speed, which is the rotational information, can be easily calculated using the output signals of the first pressure detection unit and the second pressure detection unit.

[0040] Another technical solution of the present invention provides a construction machine comprising: a fluid machine; and a vehicle body, which is equipped with and driven by the fluid machine, the fluid machine comprising: a housing; a cylinder body rotatably housed within the housing, having a cylinder chamber for fluid supply and discharge and a cylinder port communicating with the cylinder chamber; a valve plate disposed between the housing and the cylinder body in the direction of the rotation axis, having a plurality of supply and discharge ports arranged around the rotation axis and communicating with the cylinder port, and the valve plate having a detection hole formed between adjacent supply and discharge ports around the rotation axis and communicating with the cylinder port; and a pressure extraction section for extracting the pressure of the fluid flowing into the detection hole.

[0041] With this configuration, a construction machine can be provided that can obtain cylinder rotation information with a simple structure.

[0042] The effects of the invention

[0043] The aforementioned fluid machinery, rotation information calculation method, and construction machinery can obtain the rotation information of the cylinder with a simple structure. Attached Figure Description

[0044] Figure 1 This is a schematic diagram of the construction machinery according to an embodiment of the present invention.

[0045] Figure 2 This is a structural diagram showing a portion of the hydraulic motor according to the first embodiment of the present invention.

[0046] Figure 3 This is a top view of the valve plate in the first embodiment of the present invention.

[0047] Figure 4 This is a graph of the pressure waveforms of phase A and phase B in the first embodiment of the present invention.

[0048] Figure 5 This is a schematic diagram of the construction machinery in the first embodiment of the present invention, viewed from above.

[0049] Figure 6 This is an enlarged cross-sectional view of the portion of the valve plate corresponding to the lower stop detection hole in the second embodiment of the present invention.

[0050] Explanation of reference numerals in the attached figures

[0051] 1. 201. Hydraulic motor (fluid machinery); 2. Housing (outer shell); 3. Cylinder body; 4. 204. Valve plate; 5a. Bottom dead center pressure sensor (pressure detection unit, first pressure detection unit); 5b. Top dead center pressure sensor (pressure detection unit, second pressure detection unit); 7. Rear flange (outer shell); 8. Supply and exhaust ports; 9. Cylinder chamber; 10. Cylinder port; 11. Piston; 15. Supply and exhaust ports; 20a. Bottom dead center detection hole (detection hole, first detection hole); 20b. Top dead center... Detection hole (detection hole, second detection hole); 21a, bottom dead center extension hole (extension hole, first extension hole); 21b, top dead center extension hole (extension hole, second extension hole); 23, calculation unit; 23a, counting calculation unit; 23b, timer; 23c, reset unit; 25a, 25b, pressure extraction unit; 31, piston receiving recess; 32, sealing piston; 33, piston hole; 34, O-ring seal (sealing part); 204b, second surface (one surface); C, rotation axis. Detailed Implementation

[0052] Next, embodiments of the present invention will be described with reference to the accompanying drawings.

[0053] <Construction Machinery>

[0054] Figure 1 This is a rough structural diagram of construction machinery 100.

[0055] like Figure 1 As shown, the construction machinery 100 is, for example, a hydraulic excavator. The construction machinery 100 includes: a rotating body 101; a traveling body 102 disposed at the lower part of the rotating body 101; and a hydraulic motor (an example of the fluid machinery in the claims) 1, which drives the rotating body 101 and the traveling body 102.

[0056] The slewing body 101 rotates on top of the traveling body 102 using a hydraulic motor 1. The slewing body 101 includes: a cab 103 supporting an operator seated on the slewing body 101; a boom 104, one end of which is connected to the cab 103; a stick 105, one end of which is connected to the other end of the boom 104; and a bucket 106, connected to the other end of the stick 105. The boom 104 swings relative to the cab 103. The stick 105 swings relative to the boom 104. The bucket 106 swings relative to the stick 105.

[0057] [First Implementation]

[0058] <Hydraulic Motor>

[0059] Figure 2 This is a structural diagram showing a section of the hydraulic motor 1.

[0060] like Figure 2 As shown, the hydraulic motor 1 has the following main components: a housing (an example of the outer casing in the claims) 2; a cylinder 3, which is rotatably disposed within the housing 2 about a rotation axis C; a valve plate 4, which is disposed between the housing 2 and the cylinder 3 in the direction of the rotation axis C; and pressure sensors (an example of a pressure detection unit in the claims) 5a and 5b, which are disposed on the outer surface 2a of the housing 2. The hydraulic motor 1 uses working oil as a fluid to rotate the cylinder 3, and by outputting the rotation of the cylinder 3, it causes the cab 103 to rotate or the traveling vehicle 102 to travel.

[0061] The housing 2 includes: a front housing 6 having an opening 6a; and a rear flange 7 that seals the opening 6a of the front housing 6. A cylinder 3 is housed within the front housing 6. A supply / discharge port 8 for supplying and discharging working oil is formed on the rear flange 7. Working oil is supplied to or discharged from the cylinder 3 via this supply / discharge port 8.

[0062] The cylinder body 3 is engaged and fixed with a shaft (not shown) that is rotatably supported within the front housing 6. The axis of the shaft is aligned with the axis of rotation C, thereby allowing the cylinder body 3 to rotate about the axis of rotation C.

[0063] The cylinder block 3 is cylindrical. Multiple cylinder chambers 9 are formed in the cylinder block 3 in a manner that surrounds a shaft (not shown).

[0064] Multiple cylinder chambers 9 are arranged at equal intervals along a pitch circle concentric with the axis of rotation C. Each cylinder chamber 9 is a recess that opens on the bottom 6b side of the front housing 6 and closes on the rear flange 7 side. At the end 3a of the cylinder body 3 near the rear flange 7, a cylinder port 10 is formed at a position corresponding to each cylinder chamber 9, communicating between each cylinder chamber 9 and the outside of the cylinder body 3. The cylinder port 10 communicates with the supply and exhaust ports 8 of the rear flange 7 via a valve plate 4.

[0065] The piston 11 is housed in each cylinder chamber 9 in a manner that allows it to reciprocate freely along the rotation axis C. Thus, the piston 11 rotates about the rotation axis C as the cylinder body 3 rotates. A cavity is formed inside the piston 11 to collect the working oil from the cylinder chamber 9. The reciprocating motion of the piston 11 is associated with the intake and discharge of working oil from the cylinder chamber 9. Details will be discussed later.

[0066] The end of the piston 11 near the bottom 6b of the front housing 6 slidably contacts the sliding surface of a ramp (not shown) disposed on the inner surface of the bottom 6b. The sliding surface of this ramp is a flat surface inclined relative to the axis of rotation C. The ramp converts the force exerted by the pressure of the working oil on the piston 11 when the working oil is supplied into the cylinder chamber 9 into a force about the axis of rotation C. Details will be discussed later.

[0067] <Valve Plate>

[0068] The valve plate 4 is a circular plate-shaped component disposed between the rear flange 7 and the end 3a of the cylinder body 3. The valve plate 4 is fixed to the rear flange 7. Even when the cylinder body 3 rotates about the axis of rotation C, the valve plate 4 remains stationary relative to the rear flange 7. The cylinder body 3 is supported by the hydrostatic pressure of the oil film of working oil formed between the valve plate 4 and the end 3a of the cylinder body 3.

[0069] Figure 3 This is a top view of valve plate 4.

[0070] like Figure 2 , Figure 3 As shown, a through hole 12 (not shown) is formed in the radial center of the valve plate 4, extending through the thickness of the valve plate 4, for a shaft (not shown) to pass through. On the first surface 4a of the valve plate 4 near the cylinder body 3, an annular inner diameter recess 13 is formed, surrounding the through hole 12 and communicating with it, as viewed from the rotation axis C. Additionally, an annular outer diameter recess 14 is formed on the first surface 4a of the valve plate 4 along its outer periphery.

[0071] The valve plate 4 has two supply and exhaust ports 15 that communicate with each cylinder port 10 of the cylinder body 3. The two supply and exhaust ports 15 are symmetrically arranged about the rotation axis C. Each supply and exhaust port 15 is formed to pass through in the thickness direction of the valve plate 4. Each supply and exhaust port 15 includes: an elongated recess 16 formed from the first surface 4a of the valve plate 4 on the side near the cylinder body 3 to the center of the valve plate 4 in the thickness direction, and three supply and exhaust holes 17 formed from the center of the valve plate 4 in the thickness direction to the second surface 4b of the valve plate 4 on the side near the rear flange 7. The elongated recess 16 communicates with each supply and exhaust hole 17.

[0072] The elongated recess 16 is, for example, an arc within a predetermined angular range about the axis of rotation C, and is formed into an elongated oval shape. The pitch circle S of the elongated recess 16 lies on the rotation trajectory of the cylinder port 10 of the cylinder body 3. Three supply and exhaust ports 17 are arranged at equal intervals in the circumferential direction relative to the elongated recess 16. The supply and exhaust ports 8 of the rear flange 7 are connected to the cylinder port 10 of the cylinder body 3 via such supply and exhaust ports 15.

[0073] Based on such a structure, such as Figure 2 , Figure 3 As shown, when working oil is supplied to the cylinder chamber 9 via the supply / exhaust port 8 of the rear flange 7 and the cylinder port 10, the piston 11 is pushed out of the cylinder chamber 9 under the pressure of the working oil. At this time, the reaction force of the piston 11 pressing against the sliding surface of the inclined plate (not shown) is converted into a circumferential force about the rotation axis C, causing the cylinder body 3 and the piston 11 to rotate together.

[0074] From the top dead center point where the piston 11 is pushed out to its maximum extent relative to the cylinder chamber 9, the piston 11 rotates and enters the cylinder chamber 9 using a ramp (not shown). As the piston 11 enters the cylinder chamber 9, the volume of the cylinder chamber 9 decreases, and working oil is discharged from the supply and exhaust ports 8 of the rear flange 7 via the cylinder port 10. From the bottom dead center point where the piston 11 is pushed out of the cylinder chamber 9 again, the piston 11 is pushed out of the cylinder chamber 9. While repeating the above actions, the cylinder body 3 and the piston 11 rotate about the axis of rotation C.

[0075] The hydraulic motor 1 of this first embodiment has an odd number of cylinder chambers 9 (pistons 11).

[0076] Generally, the number of cylinders (pistons) in a hydraulic motor is odd. This is to minimize the flow variation of the working oil. That is, when there are 3 or more pistons and the number of pistons is odd, there are twice as many flow variations as there are pistons. Conversely, when the number of pistons is even, if the hydraulic motor is driven with the same phase difference, the flow variation becomes the same as the number of pistons, and the rate of variation is larger.

[0077] return Figure 3On the first surface 4a of the valve plate 4, a pair of switching shoulders 18a and 18b (bottom dead center switching shoulder 18a and top dead center switching shoulder 18b) are formed between the two ends of each elongated recess 16 along its length. In other words, two supply and exhaust ports 15 are formed on both sides separated by the pair of switching shoulders 18a and 18b. The pair of switching shoulders 18a and 18b are on the same plane as the first surface 4a. When the cylinder body 3 rotates, the cylinder port 10 of the cylinder body 3 switches between communicating with one of the two supply and exhaust ports 15 or with the other via the pair of switching shoulders 18a and 18b.

[0078] In the following description, the switching shoulder 18a of the pair of switching shoulders 18a and 18b that corresponds to the part of the piston 11 that changes from bottom dead center to top dead center is called the bottom dead center switching shoulder 18a. Similarly, the switching shoulder 18b of the pair of switching shoulders 18a and 18b that corresponds to the part of the piston 11 that changes from top dead center to bottom dead center is called the top dead center switching shoulder 18b.

[0079] A notch 19 is formed on the first surface 4a of the valve plate 4, extending from both ends of the elongated recess 16 toward each switching shoulder 18a, 18b along its length. The notch 19 is formed such that, viewed from the rotation axis C, it tapers from one end of the elongated recess 16 to the other. Furthermore, the depth of the notch 19 gradually decreases from one end of the elongated recess 16 to the other. The top of the notch 19 is located on the pitch circle S of the elongated recess 16 of each supply / discharge port 15.

[0080] Additionally, two detection holes 20a and 20b (bottom dead center detection hole 20a and top dead center detection hole 20b) are formed at the circumferential center of a pair of switching shoulders 18a and 18b, that is, at the top dead center and bottom dead center positions of the piston 11, and on the pitch circle S. Of the two detection holes 20a and 20b, the bottom dead center detection hole (an example of the detection hole in the claim, the first detection hole) 20a is formed on the bottom dead center switching shoulder 18a. Of the two detection holes 20a and 20b, the top dead center detection hole (an example of the detection hole in the claim, the second detection hole) 20b is formed on the top dead center switching shoulder 18b.

[0081] Each detection hole 20a and 20b is formed to extend through the thickness direction of the valve plate 4. When the cylinder port 10 of the cylinder body 3 passes over these detection holes 20a and 20b, the working oil in the cylinder chamber 9 flows into each detection hole 20a and 20b through the cylinder port 10.

[0082] On the other hand, such as Figure 2As shown, a bottom dead center extension hole (an example of the extension hole in the claim, or the first extension hole) 21a is formed on the rear flange 7, communicating with the bottom dead center detection hole 20a. Additionally, a top dead center extension hole (an example of the extension hole in the claim, or the second extension hole) 21b is formed on the rear flange 7, communicating with the top dead center detection hole 20b. Each extension hole 21a, 21b is formed in a straight line along the rotation axis C, penetrating in the thickness direction of the rear flange 7. Working oil flowing into the bottom dead center detection hole 20a flows into the bottom dead center extension hole 21a. Working oil flowing into the top dead center detection hole 20b flows into the top dead center extension hole 21b.

[0083] The openings on the second surface 4b side of the two detection holes 20a and 20b formed in the valve plate 4 function as pressure extraction parts 25a and 25b that extract the pressure of the working oil flowing into these detection holes 20a and 20b from the extended holes 21a and 21b side of the rear flange 7.

[0084] A bottom dead center pressure sensor (an example of the pressure detection unit, the first pressure detection unit, as claimed) 5a is provided on the outer surface 7a (outer surface 2a of the housing 2) of the rear flange 7, communicating with the bottom dead center extension hole 21a. Similarly, a top dead center pressure sensor (an example of the pressure detection unit, the second pressure detection unit, as claimed) 5b is provided on the outer surface 7a (outer surface 2a of the housing 2), communicating with the top dead center extension hole 21b. In other words, each pressure sensor 5a and 5b is provided on the side of the housing 2 opposite to each detection hole 20a and 20b.

[0085] Pressure sensors 5a and 5b are used to detect the pressure of the working oil that has flowed into the corresponding extension holes 21a and 21b. In other words, pressure sensors 5a and 5b are mounted on pressure extraction sections 25a and 25b via extension holes 21a and 21b. Pressure sensors 5a and 5b detect the pressure of the working oil flowing into detection holes 20a and 20b via extension holes 21a and 21b and pressure extraction sections 25a and 25b. A control unit 22 is connected to pressure sensors 5a and 5b. The pressure detected by pressure sensors 5a and 5b is output as a signal to the control unit 22.

[0086] The control unit 22 is connected to each of the pressure sensors 5a and 5b, and also to the hydraulic pump 110. The control unit 22 obtains the rotation information of the cylinder 3 based on the signals output from the pressure sensors 5a and 5b. The cylinder 3 rotates integrally with a shaft (not shown), therefore, the rotation information of the cylinder 3 is also the rotation information of the shaft (not shown).

[0087] The control unit 22 performs drive control of the hydraulic pump 110 based on the acquired rotation information of the cylinder 3. The details of the method by which the control unit 22 acquires the rotation information of the cylinder 3 will then be discussed.

[0088] Hydraulic pump 110 is a so-called swashplate-type variable capacity hydraulic pump used to spray working oil. The deflection angle of the swashplate 111 provided in hydraulic pump 110 is controlled by control unit 22, thereby controlling the flow rate of working oil sprayed from hydraulic pump 110. The discharge port 112 of such hydraulic pump 110 is connected to the supply / discharge port 8 of the rear flange 7 of hydraulic motor 1. Thus, working oil sprayed from hydraulic pump 110 is supplied to the supply / discharge port 8 of hydraulic motor 1.

[0089] <Method for obtaining cylinder rotation information by the control unit>

[0090] Next, the method for obtaining the rotation information of the cylinder 3 by the control unit 22 will be explained.

[0091] The two extended holes 21a and 21b formed in the rear flange 7 are connected to the detection holes 20a and 20b of the valve plate 4. That is, the working oil pressure in the extended hole 21a, which is connected to the lower dead center detection hole 20a, is equal to the working oil pressure in the lower dead center detection hole 20a. Similarly, the working oil pressure in the extended hole 21b, which is connected to the upper dead center detection hole 20b, is equal to the working oil pressure in the upper dead center detection hole 20b. In the following description, the working oil pressure waveform detected by the lower dead center pressure sensor 5a is referred to as the pressure waveform of phase A. The working oil pressure waveform detected by the upper dead center pressure sensor 5b is referred to as the pressure waveform of phase B.

[0092] Figure 4 It is a chart obtained by simplifying the pressure waveforms of phase A and phase B.

[0093] As the cylinder body 3 rotates, the cylinder port 10 of the cylinder body 3 is repeatedly positioned on the detection holes 20a and 20b of the valve plate 4, and the cylinder port 10 of the cylinder body 3 is not positioned on the detection holes 20a and 20b of the valve plate 4. Therefore, as Figure 4 As shown, the pressure waveforms of phase A and phase B are approximately rectangular waves (pulse waveforms). That is, the pressure waveforms of each phase increase (rise) when the corresponding detection holes 20a and 20b are connected to the cylinder port 10, and the working oil in the cylinder chamber 9 flows in. Even at the bottom dead center position of the piston 11, the working oil in the cylinder port 10 is not completely drained; therefore, when the bottom dead center detection hole 20a is connected to the cylinder port 10, the pressure at the bottom dead center detection hole 20a increases.

[0094] On the other hand, the pressure waveforms of each phase decrease (drop) when the corresponding detection holes 20a and 20b are cut off relative to the cylinder port 10. Figure 4 In the process, the pressure waveforms of each phase are represented by complete rectangular waves. However, in reality, the detection holes 20a, 20b and cylinder port 10 gradually connect as the cylinder body 3 rotates. Therefore, the rise and fall of the pressure waveforms of each phase actually become slightly smoother (slightly unstable rise and fall).

[0095] The bottom dead center detection hole 20a and the top dead center detection hole 20b are arranged opposite each other across the rotation axis C. In other words, the bottom dead center detection hole 20a and the top dead center detection hole 20b are arranged with a mechanical angle interval of 180°. Furthermore, the number of cylinder chambers 9 (piston 11) is odd. Therefore, the phase of the pressure waveform in phase A deviates from the phase of the pressure waveform in phase B by 90°. Therefore, the control unit 22 obtains the rotation direction of the cylinder 3 as rotation information of the cylinder 3 based on the phase difference between the pressure waveforms in phase A and phase B. That is, the control unit 22 detects the rising sequence of pulses in the pressure waveform in phase A and the rising sequence of pulses in the pressure waveform in phase B (sequence detection process). The rotation direction of the cylinder 3 is determined based on this pulse rising sequence (rotation direction determination process). Alternatively, the control unit 22 detects the falling sequence of pulses in the pressure waveform in phase A and the falling sequence of pulses in the pressure waveform in phase B (sequence detection process). The rotation direction of the cylinder 3 is determined based on this pulse falling sequence (rotation direction determination process).

[0096] Additionally, the control unit 22 includes a calculation unit 23 for calculating the rotational speed of the cylinder 3 and a storage unit 24. The calculation unit 23 includes: a counting calculation unit 23a that counts the pulses of the pressure waveform of each phase and outputs them as count values; a timer 23b that measures the time during which the pulses are counted; and a reset unit 23c that resets the count values ​​calculated by the counting calculation unit 23a (all referenced in the original text). Figure 2 ).

[0097] The calculation unit 23 uses the counting calculation unit 23a and the timer 23b to calculate the frequency of the pressure waveform of phase A or phase B (frequency calculation process). The calculation unit 23 performs FV conversion on the calculated frequency to generate a voltage value. The storage unit 24 stores the correction coefficient in advance. The calculation unit 23 multiplies the voltage value generated by the FV conversion by the correction coefficient to calculate the rotational speed (rotational speed) of the cylinder 3 (rotational speed calculation process).

[0098] In addition, the calculation unit 23 calculates the count value (counting process) of the counting unit 23a in addition to the rotation direction of the cylinder 3. Moreover, the calculation unit 23 calculates the rotation angle of the cylinder 3 based on the count value of each rotation direction of the cylinder 3 (rotation angle calculation process). By accumulating the rotation angle, it is possible to calculate the rotation angle formed in a certain period of time and the cumulative rotation angle when the rotation angle is calculated multiple times. In this case, in order to suppress the accumulation error, when a certain rotation angle is reached, the count value of the counting unit 23a is reset by the reset unit 23c, and the cumulative rotation angle is reset.

[0099] Furthermore, timer 23b only measures a preset time, for example. In this case, the rotation angle is calculated in multiple steps, and therefore, there is a possibility that the result may differ from the actual change in rotation speed. Therefore, when a certain rotation angle is reached, the count value of counter calculation unit 23a is reset using reset unit 23c, and the accumulated rotation angle is reset. The specific reset time is, for example, the following time.

[0100] Figure 5 This is a rough structural diagram obtained from observing the construction machinery 100 from above.

[0101] like Figure 5 As shown, the construction machinery 100 has one rotary body-side reset position 101a on the rotary body 101 side and one travel body-side reset position 102a on the travel body 102 side. Since the rotary body 101 rotates relative to the travel body 102, the travel body-side reset position 102a is fixed, while the rotary body-side reset position 101a rotates with the rotary body 101.

[0102] Based on this structure, when the rotary body side reset position 101a is located at the driving body side reset position 102a, the count value is reset by the reset unit 23c.

[0103] Thus, in the first embodiment described above, two detection holes 20a and 20b extending through the thickness direction of the valve plate 4 are formed on a pair of switching shoulders 18a and 18b of the valve plate 4. Additionally, two extension holes 21a and 21b are formed on the rear flange 7, communicating with the detection holes 20a and 20b via pressure extraction portions 25a and 25b. Pressure sensors 5a and 5b are provided on the outer surface 7a of the rear flange 7 to detect the pressure of the working oil flowing into each extension hole 21a and 21b. In other words, pressure sensors 5a and 5b are provided on the side of each extension hole 21a and 21b in the housing 2 opposite to each detection hole 20a and 20b. By repeatedly connecting or blocking the cylinder port 10 of the cylinder body 3 relative to the detection holes 20a and 20b and the extension holes 21a and 21b, the pressure of the working oil becomes a rectangular wave (pulse waveform) and is detected by each pressure sensor 5a and 5b. Therefore, the control unit 22 can easily obtain rotational information such as the rotation direction, speed, and rotation angle of the cylinder 3 (shaft not shown). Furthermore, no external rotation detection equipment is required, thus simplifying the structure of the hydraulic motor 1. Additionally, the hydraulic motor 1 can be made more cost-effective overall.

[0104] Furthermore, by forming extension holes 21a and 21b in the rear flange 7, pressure sensors 5a and 5b can be installed in the rear flange 7. In other words, the layout freedom of pressure sensors 5a and 5b used to detect the pressure of working oil in the detection holes 20a and 20b can be increased. In addition, pressure sensors 5a and 5b can be easily fixed to the housing 2.

[0105] Furthermore, each extension hole 21a and 21b is formed in a straight line along the rotation axis C, extending through the thickness direction of the rear flange 7. Therefore, pressure loss of the working oil flowing into each extension hole 21a and 21b can be suppressed. Consequently, even with the extension holes 21a and 21b formed, high-precision rotational information of the cylinder block 3 can be obtained.

[0106] Furthermore, by forming extension holes 21a and 21b in the rear flange 7, the rear flange 7, which has the supply and discharge ports 8, can be configured as a location for mounting pressure sensors 5a and 5b. As a whole, the rear flange 7 provides ample space for mounting pressure sensors 5a and 5b. Therefore, pressure sensors 5a and 5b can be easily fixed to the housing 2.

[0107] Two detection holes 20a and 20b are formed on the valve plate 4 at the top dead center and bottom dead center positions of the piston 11. Therefore, pressure sensors 5a and 5b can be used to detect a well-balanced working oil pressure waveform between the high-pressure waveform (the working oil pressure waveform at the bottom dead center position) and the low-pressure waveform (the working oil pressure waveform at the top dead center position). Thus, high-precision rotational information of the hydraulic motor 1 can be obtained.

[0108] Furthermore, two pressure waveforms with different phases (phase A pressure waveform and phase B pressure waveform) can be obtained using the two detection holes 20a and 20b. By utilizing these two pressure waveforms with a phase difference, rotation information such as the rotation direction of the cylinder 3 can be easily obtained.

[0109] In particular, including the embodiments described above, the number of cylinder chambers 9 (pistons 11) is generally odd. Therefore, the phase of the pressure waveform in phase A and the phase of the pressure waveform in phase B are exactly 90° apart. Thus, regardless of the rotation direction of the cylinder body 3, the output signals of each pressure sensor 5a and 5b can be detected at the same time to obtain the rotation information of the cylinder body 3.

[0110] When acquiring rotational information, the control unit 22 includes a calculation unit 23 for calculating the rotational speed of the cylinder 3 and a storage unit 24. Therefore, the rotational speed of the cylinder 3 can be easily obtained. The calculation unit 23 can easily calculate the rotational direction of the cylinder 3 based on the pressure waveform of phase A and the pressure waveform of phase B.

[0111] More specifically, the control unit 22 detects the rising sequence of pulses in the pressure waveform of phase A and the rising sequence of pulses in the pressure waveform of phase B (sequence detection process). The rotation direction of the cylinder 3 is determined based on this pulse rising sequence (rotation direction determination process). Alternatively, the control unit 22 detects the falling sequence of pulses in the pressure waveform of phase A and the falling sequence of pulses in the pressure waveform of phase B (sequence detection process). The rotation direction of the cylinder 3 is determined based on this pulse falling sequence (rotation direction determination process). Therefore, the rotation direction of the cylinder 3 can be easily calculated using the pressure waveforms of phase A and phase B.

[0112] Furthermore, the calculation unit 23 includes a counting calculation unit 23a that counts the pulses of the pressure waveform of each phase and outputs the count value. Therefore, the rotation angle of the cylinder 3 can be easily calculated based on the count value counted by the counting calculation unit 23a.

[0113] Furthermore, the calculation unit 23 includes a timer 23b for measuring the time during which the pulses are counted and a reset unit 23c for resetting the count value calculated by the counting unit 23a. The calculation unit 23 uses the counting unit 23a and the timer 23b to calculate the frequency of the pressure waveform of phase A or phase B (frequency calculation process). The calculation unit 23 performs an FV conversion on the calculated frequency to generate a voltage value. Based on this voltage value, the rotational speed (speed calculation process) of the cylinder 3 is calculated. Therefore, the rotational speed of the cylinder 3 can be easily calculated.

[0114] In addition, the cumulative error when calculating the rotation angle of the cylinder 3 can be reduced by using the reset unit 23c.

[0115] [Second Implementation]

[0116] Next, based on Figure 6 The second embodiment of the present invention will be described. Reference numerals are used for the same aspects as in the first embodiment, and descriptions are omitted.

[0117] Figure 6 This is an enlarged cross-sectional view of the part of the hydraulic motor 201 in the second embodiment that corresponds to the lower dead center detection hole 20a of the valve plate 204.

[0118] In the second embodiment, the structure of forming two detection holes 20a and 20b on the valve plate 204 is the same as that in the first embodiment described above. Since the structures of the portions of the valve plate 204 corresponding to each detection hole 20a and 20b are identical, therefore, in Figure 5 In this diagram, only the portion of the valve plate 204 corresponding to the lower dead center detection hole 20a is shown, while the upper dead center detection hole 20b is omitted. Furthermore, in the following description, only the lower dead center detection hole 20a will be described, but the upper dead center detection hole 20b also has the same structure.

[0119] Piston housing recess and piston sealing section

[0120] like Figure 6 As shown, on the second surface (an example of a surface in the claim) 204b side of the valve plate 204, a piston receiving recess 31 is formed at a position corresponding to the bottom dead center detection hole 20a. A sealing piston 32 is received in this piston receiving recess 31. These points differ from those in the first embodiment described above.

[0121] The piston receiving recess 31 is circular when viewed from the rotation axis C. The bottom dead center detection hole 20a is connected to the radial center of the piston receiving recess 31.

[0122] The sealing piston 32 is formed in the shape of a circular plate. The thickness of the sealing piston 32 is slightly thinner than the depth of the piston receiving recess 31. The outer diameter of the sealing piston 32 is slightly smaller than the inner diameter of the piston receiving recess 31.

[0123] A piston hole 33 is formed in the radial center of the sealing piston 32, extending through the thickness direction of the sealing piston 32. The bottom dead center detection hole 20a of the valve plate 204 and the bottom dead center extension hole 21a of the rear flange 7 are connected via the piston hole 33. The opening of the bottom dead center detection hole 20a formed in the valve plate 204 on the side near the piston receiving recess 31 functions as a pressure extraction part 25a that extracts the pressure of the working oil flowing into the bottom dead center detection hole 20a from the piston hole 33 side.

[0124] Furthermore, an O-ring (an example of the sealing portion in the claim) 34 is provided on the outer peripheral surface of the piston receiving recess 31 near the bottom surface 31a of the sealing piston 32. The O-ring 34 ensures a tight seal between the inner peripheral surface of the piston receiving recess 31 and the outer peripheral surface of the sealing piston 32.

[0125] <The function of the piston>

[0126] Next, the function of the blocking piston 32 will be explained.

[0127] If working oil flows into the bottom dead center detection hole 20a of the valve plate 204, it flows into the piston receiving recess 31. An oil film is then formed between the bottom surface 31a of the piston receiving recess 31 and the sealing piston 32. Due to the hydrostatic pressure of this oil film, the sealing piston 32 is pushed towards the rear flange 7. This improves the sealing performance between the sealing piston 32 and the rear flange 7.

[0128] Furthermore, working oil flows into the piston bore 33 of the sealing piston 32, and further, the working oil flows into the bottom dead center extension hole 21a of the rear flange 7. At this time, since the sealing performance between the sealing piston 32 and the rear flange 7 is ensured, leakage of working oil from between the sealing piston 32 and the rear flange 7 is prevented. In addition, since an O-ring seal 34 is provided on the outer peripheral surface of the sealing piston 32, leakage of working oil from between the inner peripheral surface of the piston receiving recess 31 and the outer peripheral surface of the sealing piston 32 is prevented.

[0129] Therefore, according to the second embodiment described above, the same effect as that of the first embodiment is achieved. Furthermore, since a piston receiving recess 31 is formed in the valve plate 204, and a sealing piston 32 is provided in this piston receiving recess 31, leakage of working oil from between the rear flange 7 and the valve plate 204 can be suppressed. Therefore, the pressure of the working oil in the lower dead center detection hole 20a can be detected with greater accuracy using the lower dead center pressure sensor 5a. By providing an O-ring seal 34 on the outer peripheral surface of the sealing piston 32, the pressure of the working oil in the lower dead center detection hole 20a can be detected with greater accuracy using the lower dead center pressure sensor 5a.

[0130] This invention is not limited to the embodiments described above, but includes various modifications made to the embodiments described above without departing from the spirit of this invention.

[0131] For example, in the above embodiment, the case where detection holes 20a and 20b are formed at the bottom dead center and top dead center positions of the valve plates 4 and 204 and the piston 11 has been described. However, it is not limited to this; detection holes 20a and 20b can be formed at any location between the supply and exhaust ports 15 of the valve plates 4 and 204, that is, at either the bottom dead center switching shoulder 18a or the top dead center switching shoulder 18b. In this case, the phase difference between the pressure waveform of phase A and the pressure waveform of phase B is not limited to 90°, but can be any value between 10° and 170°, or between 190° and 350°. With this configuration, it is possible to prevent the overlap of unstable waveforms during the rising and falling phases of the pressure waveforms of each phase, which would make it difficult to obtain accurate rotation information of the cylinder 3. It is desirable that the phase difference between the pressure waveform of phase A and the pressure waveform of phase B is 90° or 270°. Even 270° will have the same effect as the first embodiment described above.

[0132] In the above embodiment, the case where two detection holes 20a and 20b are formed in the valve plates 4 and 204 has been described. However, it is not limited to this, and at least one detection hole is sufficient. As long as one detection hole is formed, the rotational speed and rotational angle, which are rotational information of the cylinder 3, can be obtained by the control unit 22.

[0133] In the above embodiment, the case where extension holes 21a and 21b are formed in the rear flange 7 and the pressure of the working oil flowing into these extension holes 21a and 21b is detected by pressure sensors 5a and 5b is described. However, it is not limited to this, and the extension holes 21a and 21b may not be formed. Alternatively, the configuration may be such that the pressure of the working oil flowing into each detection hole 20a and 20b is detected by pressure sensors 5a and 5b.

[0134] Furthermore, hydraulic motors 1 and 201 can have pressure extraction units 25a and 25b to extract the pressure of the working oil flowing into each detection port 20a and 20b. The pressure of the working oil extracted by these pressure extraction units 25a and 25b can be detected using pressure sensors 5a and 5b, etc.

[0135] In the above embodiment, it was described that each extension hole 21a, 21b is formed in a straight line along the rotation axis C in a manner that extends through the thickness direction of the rear flange 7. However, it is not limited to this, and the shape of each extension hole 21a, 21b can be changed according to the layout of each pressure sensor 5a, 5b.

[0136] In the above embodiment, the case where two supply and discharge ports 15 are formed in valve plates 4 and 204 has been described. However, it is not limited to this, and the number of supply and discharge ports 15 can be more than three. Detection holes 20a and 20b can be formed between adjacent supply and discharge ports 15 about the rotation axis C.

[0137] In the above embodiments, hydraulic motors 1 and 201 driven by working oil have been described. However, this is not a limitation, and the above structure can be applied to fluid machinery driven by various fluids.

[0138] In the above embodiments, the method for calculating the rotational speed of the cylinder 3 is described as follows: the calculation unit 23 uses the counting calculation unit 23a and the timer 23b to calculate the frequency of the pressure waveform of phase A or phase B, and performs an FV conversion on that frequency to generate a voltage value. Additionally, the method describes a case where a correction coefficient is pre-stored in the storage unit 24, and the calculation unit 23 multiplies the voltage value generated by the FV conversion by the correction coefficient to calculate the rotational speed of the cylinder 3. However, this is not a limitation; the timer 23b can also be used to measure the time during which the counting calculation unit 23a counts the pulses (counting process), and the rotational speed of the cylinder 3 can be calculated based on these pulses and the time (rotational speed calculation process). Alternatively, the rotational speed of the cylinder 3 can be calculated using the time until the counting calculation unit 23a reaches a certain count value (rotational speed calculation process).

[0139] In the above embodiment, the case where one driving body-side reset position 102a is provided on the driving body 102 has been described. However, it is not limited to this, and two or more driving body-side reset positions 102a may also be provided. For example, when multiple driving body-side reset positions 102a are provided, the driving body-side reset positions 102a are arranged at 90° intervals in mechanical angle, thereby enabling the reset unit 23c to further reduce the accumulated error when calculating the rotation angle of the cylinder block 3.

[0140] The components comprising multiple objects in the embodiments disclosed in this specification can either be integrated into one unit, or the component comprising a single object can be divided into multiple objects. Regardless of whether they are integrated or not, the configuration is sufficient to achieve the purpose of the invention.

[0141] Industrial availability

[0142] The aforementioned fluid machinery, rotation information calculation method, and construction machinery can obtain the rotation information of the cylinder with a simple structure.

Claims

1. A fluid machine, wherein the fluid machine is provided with: a housing; a cylinder body housed in the housing in a manner rotatable about a rotational axis, having a cylinder chamber for supply and discharge of a fluid and a cylinder port communicating with the cylinder chamber; a valve plate disposed between the housing and the cylinder body in the direction of the rotational axis, having a plurality of supply and discharge ports communicating with the cylinder port arranged around the rotational axis, and having a detection hole formed between the supply and discharge ports adjacent around the rotational axis, communicating with the cylinder port; and a pressure extraction portion extracting the pressure of the fluid flowing into the detection hole, the valve plate is provided with: a piston housing recess formed in a portion of a surface of the valve plate on the housing side, in which the detection hole is formed; and a blocking piston housed in the piston housing recess in a manner blocking the opening of the piston housing recess, having a piston hole communicating with the detection hole.

2. The fluid machine according to claim 1, wherein the fluid machine is provided with a pressure detection portion mounted to the pressure extraction portion for detecting the pressure of the fluid.

3. The fluid machine according to claim 1, wherein the fluid machine is provided with a piston disposed in the cylinder chamber in a manner reciprocable along the rotational axis, the detection hole is formed in at least either of a top dead center position and a bottom dead center position of the piston in the valve plate.

4. The fluid machine according to any one of claims 1 to 3, wherein the housing has an extension hole communicating with the detection hole, the pressure extraction portion extracts the pressure of the detection hole via the extension hole.

5. The fluid machine according to claim 4, wherein the extension hole is formed on a straight line.

6. The fluid machine according to claim 1, wherein the housing is a rear end flange having a supply and discharge port for supply and discharge of the fluid, communicating with the supply and discharge ports.

7. The fluid machine according to claim 1, wherein the fluid machine is provided with a sealing portion preventing leakage of the fluid between an inner side surface of the piston housing recess and an outer side surface of the blocking piston.

8. The fluid machine according to claim 2, wherein the fluid machine is provided with a calculation portion calculating a rotational speed of the cylinder body based on a detection result of the pressure detection portion.

9. The fluid machine according to claim 2, wherein the detection hole has at least a first detection hole and a second detection hole, the pressure detection portion has a first pressure detection portion outputting a detection result of the pressure of the fluid flowing into the first detection hole as a signal, and a second pressure detection portion outputting a detection result of the pressure of the fluid flowing into the second detection hole as a signal, the first detection hole and the second detection hole are formed in a manner such that the output signal of the first pressure detection portion and the output signal of the second pressure detection portion have a phase difference.

10. The fluid machine according to claim 9, wherein The housing has a first extension hole communicating with the first detection hole and a second extension hole communicating with the second detection hole, The first pressure detection portion is provided on the side of the first extension hole opposite the first detection hole, The second pressure detection portion is provided on the side of the second extension hole opposite the second detection hole.

11. The fluid machine according to claim 9, wherein The phase difference is any value between 10° and 170°, or between 190° and 350°.

12. The fluid machine according to claim 11, wherein The phase difference is 90° or 270°.

13. The fluid machine according to claim 9, wherein The fluid machine is provided with a calculation portion that calculates the rotation direction of the cylinder based on the output signal of the first pressure detection portion and the output signal of the second pressure detection portion.

14. The fluid machine according to claim 13, wherein The calculation portion has a count calculation portion that counts the pulses of at least either the output signal of the first pressure detection portion or the output signal of the second pressure detection portion, and calculates the rotation angle of the cylinder based on the count value.

15. The fluid machine according to claim 14, wherein The calculation portion has a reset portion that resets the count value of the count calculation portion when the rotation angle of the cylinder reaches a certain angle.

16. The fluid machine according to claim 14 or 15, wherein The calculation portion has a timer that measures the time for which the pulses are counted.

17. A rotation information calculation method that is a rotation information calculation method for a fluid machine provided with: a housing; a cylinder housed in the housing so as to be rotatable about a rotation axis, having a cylinder chamber for supplying and discharging a fluid and a cylinder port communicating with the cylinder chamber; a valve plate disposed between the housing and the cylinder in the direction of the rotation axis, having a plurality of supply and discharge ports arranged in a row about the rotation axis and communicating with the cylinder port, and having a first detection hole and a second detection hole formed between the supply and discharge ports adjacent about the rotation axis and communicating with the cylinder port; and a calculation portion that calculates the rotation direction of the cylinder based on the phase difference between the pressure waveform of the output signal of the first pressure detection portion and the pressure waveform of the output signal of the second pressure detection portion, wherein the rotation information calculation method has: a sequence detection step in which the calculation portion detects the rising sequence of the pulses of the pressure waveforms of the output signal of the first pressure detection portion and the output signal of the second pressure detection portion; and a rotation direction determination step in which the rotation direction of the cylinder is determined based on the sequence detected in the sequence detection step.

18. A rotation information calculation method that is a rotation information calculation method for a fluid machine provided with: a housing; a cylinder housed in the housing so as to be rotatable about a rotation axis, having a cylinder chamber for supplying and discharging a fluid and a cylinder port communicating with the cylinder chamber; a valve plate disposed between the housing and the cylinder in the direction of the rotation axis, having a plurality of supply and discharge ports arranged in a row about the rotation axis and communicating with the cylinder port, and having a first detection hole and a second detection hole formed between the supply and discharge ports adjacent about the rotation axis and communicating with the cylinder port; and a calculation portion that calculates the rotation direction of the cylinder based on the phase difference between the pressure waveform of the output signal of the first pressure detection portion and the pressure waveform of the output signal of the second pressure detection portion, wherein the rotation information calculation method has: a sequence detection step in which the calculation portion detects the rising sequence of the pulses of the pressure waveforms of the output signal of the first pressure detection portion and the output signal of the second pressure detection portion; and a rotation direction determination step in which the rotation direction of the cylinder is determined based on the sequence detected in the sequence detection step. ​ ​ a first pressure detecting portion that outputs, as a signal, a result of detection of a pressure of the fluid flowing into the first detecting hole, and a second pressure detecting portion that outputs, as a signal, a result of detection of a pressure of the fluid flowing into the second detecting hole; ​ ​ ​ ​ ​ ​ ​ ​ ​ a valve plate disposed between the housing and the cylinder in the direction of the rotation axis, formed with a plurality of supply and discharge ports communicating with the cylinder port, arranged around the rotation axis, and having a first detection hole and a second detection hole formed between the supply and discharge ports adjacent around the rotation axis, communicating with the cylinder port; a first pressure detecting portion that outputs, as a signal, a result of detection of a pressure of the fluid flowing into the first detecting hole, and a second pressure detecting portion that outputs, as a signal, a result of detection of a pressure of the fluid flowing into the second detecting hole; and an arithmetic unit that calculates the rotation direction of the cylinder on the basis of the output signal of the first pressure detection unit and the output signal of the second pressure detection unit, the rotation information calculation method has: a counting step in which the arithmetic unit counts the pulses of at least either of the output signal of the first pressure detection unit and the output signal of the second pressure detection unit; and a rotation angle calculation step that calculates the rotation angle of the cylinder on the basis of the count value of the counting step.

19. A rotation information calculation method that is a rotation information calculation method of a fluid machine that has: a housing; a cylinder housed in the housing in a manner rotatable around a rotation axis, having a cylinder chamber for supply and discharge of fluid and a cylinder port communicating with the cylinder chamber; a valve plate disposed between the housing and the cylinder in the direction of the rotation axis, formed with a plurality of supply and discharge ports communicating with the cylinder port, arranged around the rotation axis, and having a first detection hole and a second detection hole formed between the supply and discharge ports adjacent around the rotation axis, communicating with the cylinder port; a first pressure detection unit that outputs as a signal the detection result of the pressure of the fluid flowing into the first detection hole, and a second pressure detection unit that outputs as a signal the detection result of the pressure of the fluid flowing into the second detection hole; and an arithmetic unit that calculates the rotation direction of the cylinder on the basis of the output signal of the first pressure detection unit and the output signal of the second pressure detection unit, the arithmetic unit has: a counting arithmetic unit that counts the pulses of at least either of the output signal of the first pressure detection unit and the output signal of the second pressure detection unit, and calculates the rotation angle of the cylinder on the basis of the count value; and a timer for measuring the time for which the pulses are counted, the rotation information calculation method has: a frequency calculation step in which the arithmetic unit calculates the frequency of at least either of the output signal of the first pressure detection unit and the output signal of the second pressure detection unit; and a rotation speed calculation step that calculates the rotation speed of the cylinder on the basis of a voltage value generated by FV conversion of the frequency calculated by the frequency calculation step.

20. A rotation information calculation method that is a rotation information calculation method of a fluid machine that has: a housing; a cylinder housed in the housing in a manner rotatable around a rotation axis, having a cylinder chamber for supply and discharge of fluid and a cylinder port communicating with the cylinder chamber; a valve plate disposed between the housing and the cylinder in the direction of the rotation axis, formed with a plurality of supply and discharge ports communicating with the cylinder port, arranged around the rotation axis, and having a first detection hole and a second detection hole formed between the supply and discharge ports adjacent around the rotation axis, communicating with the cylinder port; a valve plate disposed between the housing and the cylinder in the direction of the rotation axis, formed with a plurality of supply and discharge ports communicating with the cylinder port, arranged around the rotation axis, and having a first detection hole and a second detection hole formed between the supply and discharge ports adjacent around the rotation axis, communicating with the cylinder port; a first pressure detecting portion that outputs, as a signal, a result of detection of a pressure of the fluid flowing into the first detecting hole, and a second pressure detecting portion that outputs, as a signal, a result of detection of a pressure of the fluid flowing into the second detecting hole; and an arithmetic unit that calculates the rotation direction of the cylinder on the basis of the output signal of the first pressure detection unit and the output signal of the second pressure detection unit, the arithmetic unit has: a count arithmetic unit that counts the pulses of at least either of the output signal of the first pressure detection unit and the output signal of the second pressure detection unit, and calculates the rotation angle of the cylinder on the basis of the count value; and a timer for measuring the time during which the pulses are counted, wherein the rotation information calculation method has: a count process in which the arithmetic unit counts the pulses of at least either of the output signal of the first pressure detection unit and the output signal of the second pressure detection unit; and a rotation speed calculation process in which the rotation speed of the cylinder is calculated on the basis of the count value of the count process within a certain time.

21. A rotation information calculation method that is a rotation information calculation method of a fluid machine, the fluid machine having: a housing; a cylinder housed in the housing in a manner rotatable around a rotation axis, having a cylinder chamber for supply and discharge of fluid and a cylinder port communicating with the cylinder chamber; a valve plate disposed between the housing and the cylinder in the direction of the rotation axis, formed with a plurality of supply and discharge ports communicating with the cylinder port, arranged around the rotation axis, and having a first detection hole and a second detection hole formed between the supply and discharge ports adjacent around the rotation axis, communicating with the cylinder port; a first pressure detecting portion that outputs, as a signal, a result of detection of a pressure of the fluid flowing into the first detecting hole, and a second pressure detecting portion that outputs, as a signal, a result of detection of a pressure of the fluid flowing into the second detecting hole; and an arithmetic unit that calculates the rotation direction of the cylinder on the basis of the output signal of the first pressure detection unit and the output signal of the second pressure detection unit, the arithmetic unit has: a count arithmetic unit that counts the pulses of at least either of the output signal of the first pressure detection unit and the output signal of the second pressure detection unit, and calculates the rotation angle of the cylinder on the basis of the count value; and a timer for measuring the time during which the pulses are counted, wherein the rotation information calculation method has: a count process in which the arithmetic unit counts the pulses of at least either of the output signal of the first pressure detection unit and the output signal of the second pressure detection unit; and a rotation speed calculation process in which the rotation speed of the cylinder is calculated on the basis of the time required for reaching a certain count value in the count process.

22. A construction machine, wherein the construction machine has: a fluid machine; and a vehicle body that mounts the fluid machine and is driven by the fluid machine, the fluid machine has: a housing; a cylinder housed in the housing in a manner rotatable around a rotation axis, having a cylinder chamber for supply and discharge of fluid and a cylinder port communicating with the cylinder chamber; a valve plate disposed between the housing and the cylinder body in the rotation axis direction, arranged with a plurality of supply / discharge ports communicating with the cylinder ports around the rotation axis, and having a detection hole formed between the supply / discharge ports adjacent around the rotation axis, communicating with the cylinder ports; and a pressure extraction portion that extracts the pressure of the fluid flowing into the detection hole, the valve plate has: a piston housing recess formed in a portion of one surface of the valve plate on the housing side where the detection hole is formed; and a blocking piston housed in the piston housing recess so as to block the opening of the piston housing recess, formed with a piston hole communicating with the detection hole.

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