JP2009174504A - Hydraulic pump/motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a hydraulic pump/motor capable of accurately detecting the rotation speed of a cylinder block although rotation of the cylinder block includes vibration. <P>SOLUTION: The hydraulic pump motor is provided with a detected part 52 formed on an outer peripheral surface of the cylinder block 14, and a rotation sensor 50 arranged to face the detected part 52 and provided with a detecting part 51 detecting the detected part 52. The detecting part 51 of the rotation sensor 50 is arranged in a plane containing both a line on a sliding surface S of a swash plate 17 orthogonal to a shaft center 13a of a rotary shaft 13 and the shaft center 13a. Accordingly, a distance between the detecting part 51 and the detected part 52 is kept almost constant although rotation of the cylinder block 14 includes vibration, and accuracy in detecting the rotation speed of the cylinder block can be improved. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a hydraulic pump motor having a rotation sensor.

  Conventionally, in construction machines and the like, a hydraulic pump driven by an engine and a hydraulic motor driven by oil are frequently used.

  For example, an axial-type swash plate hydraulic pump / motor is reciprocally movable in a plurality of cylinder holes formed in the cylinder block, a rotary shaft that is rotatably mounted in the casing, a cylinder block that rotates together with the rotary shaft. A plurality of pistons that are fitted in, a swash plate that is provided in the casing so as to be inclined with respect to the rotation axis, and that slidably supports the piston tip portion, and a valve plate that is slidably contacted with the rear end surface of the cylinder block. The oil is circulated into the cylinder hole through a port provided in the valve plate.

  When this swash plate type hydraulic pump / motor is used as a hydraulic pump, it is sucked into the cylinder hole from the port on the low pressure side by rotating the cylinder block by rotating the rotary shaft with an engine etc. and reciprocating the piston. The pressurized oil is pressurized by the piston and discharged from the port on the high pressure side.

  When using a swash plate type hydraulic pump / motor as a hydraulic motor, oil is supplied to the cylinder hole from the high-pressure side port, and the piston protrudes from the cylinder hole and presses the swash plate to rotate with the cylinder block. Rotate the shaft.

  Among such swash plate type hydraulic pumps and motors, those equipped with a rotation sensor for detecting the number of rotations of a cylinder block are known (see Patent Document 1). FIG. 7 is a cross-sectional view showing a schematic configuration of a swash plate type hydraulic pump / motor disclosed in Patent Document 1. The swash plate hydraulic pump / motor 100 includes a casing 110, a lid 120, a rotating shaft 130, a cylinder block 140, a piston 150, a valve plate 160, and a swash plate 170. On the outer peripheral surface of the cylinder block 140, detected recesses 520 are formed with a predetermined interval. An electromagnetic pickup type rotation sensor 500 that detects the detected recess 520 is disposed at a position facing the detected recess 520 and is fixed to the casing 110. When the cylinder block 140 rotates, each detected recess 520 passes through the position of the rotation sensor 500, and thus the distance (magnetic field) between the rotation sensor 500 and the detected recess 520 changes periodically. The rotation sensor 500 transmits a detection signal corresponding to the magnetic field change to a controller (not shown). The controller shapes the AC waveform of the detection signal from the rotation sensor 500 and calculates the frequency as the number of rotations of the cylinder block 140.

JP 2002-267679 A

  By the way, the swash plate type hydraulic pump described above changes the position of the piston sliding in the cylinder holes arranged on the same circumference by rotating the cylinder block. In addition, the swash plate hydraulic motor rotates the cylinder block by supplying high-pressure oil into the cylinder holes arranged on the same circumference, thereby changing the position of the piston sliding in the cylinder hole over time. Let For this reason, in any case of the pump and the motor, the rotation of the cylinder block is a whirling rotation accompanied by vibration in the inclination angle direction (arrow in FIG. 7) of the swash plate 170 as shown in FIG.

  In the swash plate type hydraulic pump / motor shown in FIG. 7, the rotation sensor 500 is disposed in a plane including both the line in the inclination angle direction of the swash plate 170 and the axis 130a. For this reason, the distance between the rotation sensor 500 to which the casing 110 is attached and the detected recess 520 provided in the cylinder block 140 changes due to the swing of the cylinder block 140. There is a problem that an error occurs in detection.

  The present invention has been made in view of the above, and an object of the present invention is to provide a hydraulic pump / motor that can accurately detect the rotational speed of a cylinder block regardless of the swing of the cylinder block.

  According to a first aspect of the present invention, there is provided a hydraulic pump / motor that reciprocates within a plurality of cylinder holes formed in the cylinder block, a rotary shaft that is rotatably mounted in a casing, a cylinder block that rotates together with the rotary shaft, and the cylinder block. A hydraulic pump having a plurality of pistons that are movably inserted, and a swash plate that is provided in the casing so as to be inclined with respect to the rotation shaft and that slides the tip portions of the plurality of pistons in a sliding manner. In the motor, a detected portion formed on the outer peripheral surface of the cylinder block, and a rotation sensor provided on the casing so as to face the detected portion and provided with a detecting portion that detects the detected portion. And the detection unit of the rotation sensor is arranged in a plane including both the line on the swash plate perpendicular to the axis of the rotation axis and the axis.

  A hydraulic pump / motor according to a second aspect of the present invention is the hydraulic pump / motor according to the first aspect, wherein the rotation sensor is located between the deepest part of the cylinder hole and the rear end surface of the cylinder block in the axial direction of the cylinder block. It is provided in a corresponding position.

  The hydraulic pump / motor according to the present invention has a detection portion formed on the outer peripheral surface of the cylinder block, and a rotation sensor having a detection portion for detecting the detection portion is connected to a swash plate orthogonal to the axis of the rotation shaft. It is set as the structure arrange | positioned in the surface containing both the line and axial center on a sliding surface. The position of the rotation sensor is a position that is not easily affected by the swing of the cylinder block. Therefore, the distance between the detection unit and the detected unit is kept substantially constant regardless of the swing of the cylinder block. As a result, the detection accuracy of the rotational speed of the cylinder block can be improved as compared with the conventional case.

  Exemplary embodiments of a hydraulic pump / motor according to the present invention will be described below in detail with reference to the accompanying drawings. In the following embodiment, an example in which the hydraulic pump / motor of the present invention is applied to a swash plate type hydraulic motor for driving a fan of a fan driving device will be described.

  1 is a cross-sectional view (cross-sectional view in the XZ plane) showing a schematic configuration of the swash plate type hydraulic motor 10, and FIG. 2 is a cross-sectional view taken along line AA of the swash plate type hydraulic motor shown in FIG. FIG. 3 is a cross-sectional view of the swash plate type hydraulic motor 10 shown in FIG. 4 is a rear view of the fan drive device to which the swash plate type hydraulic motor shown in FIG. 1 is applied, FIG. 5 is a sectional view taken along the line CC in FIG. 4, and FIG. 6 is a line DD in FIG. It is sectional drawing.

  A fan driving device 60 shown in FIGS. 4 to 6 is a device for driving a fan for cooling a radiator 80 of an engine such as a construction machine. The fan drive device 60 is rotatably attached to a swash plate type hydraulic motor 10 (hereinafter referred to as “hydraulic motor” for short), a bracket 61 that supports the hydraulic motor 10, and a rotating shaft of the hydraulic motor 10. A fan 62 driven by the motor 10 and a shroud 63 are included.

  The hydraulic motor 10 converts oil supplied from the hydraulic pump 2 (see FIG. 1) into rotational force and rotates the fan 62. As shown in FIG. 5, a rotation sensor 50 that detects the number of rotations of the fan 62 is attached to the rear end side of the hydraulic motor 10. The hydraulic motor 10 and the rotation sensor 50 will be described in detail later.

  The bracket 61 is a plate-like member to which the hydraulic motor 10 is attached. The bracket 61 has a base 65 having a long plate shape whose longitudinal dimension is substantially the same as that of the radiator 80, and a flat plate bent at right angles from both side edges of the base 65 toward the rear. And a side wall portion 66 formed. A through hole 64 for attaching the hydraulic motor 10 is formed at the center of the base 65.

  As shown in FIG. 5, in the hydraulic motor 10, the tip of the rotating shaft 13 protrudes from the surface side (fan installation side) of the base portion 65 of the bracket 61, and the rotation sensor 50 is positioned near the back surface of the base portion 65. In the state, it is inserted into the through hole 64 and fixed to the base portion 65 by a plurality of bolts 71. As shown in FIG. 6, a part located on the rear side of the base part of the hydraulic motor 10, that is, a rear end side of the casing 11 and an end cover 12 described later, are covered with side wall parts 66 of the bracket 61.

  The fan 62 includes a fan boss 67 and a plurality of blades 68. Each blade 68 is fastened to a fan boss 67 by a bolt, and the fan boss 67 is fastened to the rotating shaft 13 of the hydraulic motor 10 by a bolt 72. When the hydraulic motor 10 is driven, the fan 62 rotates.

  The shroud 63 is a square frame-like member arranged in a front view so as to surround the fan 62 in order to improve the air blowing performance of the fan 62, and is attached to the radiator 80 and the bracket 61 using an appropriate means. It has been. As shown in FIG. 4, a circular opening 69 is provided in the center of the shroud 63.

  In the fan drive device 60 having the above-described configuration, when the hydraulic motor 10 is driven, the fan 62 rotates, and the low-temperature air sucked by the rotation of the fan 62 passes through the radiator 80, thereby facilitating heat exchange of the radiator 80. Is done.

  Next, the hydraulic motor 10 that drives the fan 62 will be described in detail with reference to FIGS. The hydraulic motor 10 includes a casing 11, an end cover 12, a rotating shaft 13, a cylinder block 14, a piston 15, a valve plate 16, and a swash plate 17.

  The casing 11 accommodates the rotary shaft 13, the cylinder block 14, the valve plate 16, and the swash plate 17 in the inside thereof, and has a cylindrical shape composed of a cylindrical portion 21 having one end opened and an end wall portion 22. Is made. Hereinafter, the end wall portion 22 side of the casing 11 is referred to as “front end side”, and the opening side is referred to as “rear end side”. As shown in FIGS. 1 to 3, the cylindrical portion 21 is formed with a flange-shaped attachment portion 18 that protrudes radially outward from an end portion on the opening side. The attachment portion 18 is provided with a bolt hole (not shown) for attaching the hydraulic motor 10 to the bracket 61 of the fan drive device described above. As shown in FIGS. 5 and 6, the attachment portion 18 is brought into contact with the back surface of the base portion 65 when the hydraulic motor 10 is attached to the base portion 65 of the bracket 61 in the fan driving device, and is fastened to the base portion 65 by the bolt 71. Is done.

  The end cover 12 is a lid that closes the opening on the rear end side of the casing 11. A direction switching valve 1 is built in the end cover 12, and the supply / discharge direction of oil from the hydraulic pump 2 is switched by switching the spool 1 a. An oil seal 23 a is provided between the end wall portion 22 of the cylindrical portion 21 in the casing 11 and the rotary shaft 13. An oil seal 23 b is provided between the casing 11 and the end cover 12. Oil is sealed in the casing 11 by the oil seal 23a and the oil seal 23b.

  The rotating shaft 13 is rotatably supported by the casing 11 and the end cover 12 via bearings 24a and 24b. The above-described fan boss 67 of the fan 62 is attached to the tip of the rotating shaft 13. In the following description, the side on which the rotating shaft 13 is supported by the bearing 24a is referred to as the proximal end side of the rotating shaft, and the side on which the rotating shaft 13 is supported by the bearing 24b is referred to as the distal end side of the rotating shaft.

  The cylinder block 14 is connected to the rotary shaft 13 via the spline 26 and rotates integrally with the rotary shaft 13 in the casing 11. The cylinder block 14 has a front end surface 27 (hereinafter referred to as “front end surface 27”) facing the swash plate 17, while a rear end side surface 28 (hereinafter referred to as “rear end surface 28”) is the valve plate 16. It is arranged so as to be in sliding contact with the surface of the valve, and is rotatable while in contact with the valve plate 16. As shown in FIG. 1, a plurality of cylinder holes 29 are formed in the cylinder block 14 at equal intervals in the circumferential direction around the axis of the cylinder block 14 and in parallel with the rotation shaft 13. A cylinder port 32 communicating with a supply / exhaust port 31 of a valve plate 16 described later is formed at the base end portion of each cylinder hole 29 located on the rear end face 28 side of the cylinder block 14.

  The piston 15 is fitted in each cylinder hole 29 so as to reciprocate. The piston 15 presses the swash plate by supplying oil into the cylinder hole 29, and generates a rotational force in the cylinder block 14 by the force of the rotational direction component generated when the swash plate 17 is pressed. is there. As shown in FIG. 1, the tip of each piston 15 has a structure in which a piston shoe 33 is attached to a concave spherical portion. The piston shoe 33 is slidably slidably contacted with the sliding surface S of the swash plate 17 by the shoe retainer 34.

  The valve plate 16 is formed in a disc shape, and is fixed to the end cover 12 so as to be in sliding contact with the rear end surface 28 of the cylinder block 14. As shown in FIG. 3, the valve plate 16 includes long hole-shaped supply / discharge ports 31, 31 formed along the circumferential direction. As shown in FIG. 1, each supply / exhaust port 31 passes through the valve plate 16 in the axial direction, and the opening on the side in contact with the cylinder block 14 can communicate with a plurality of cylinder ports 32. The opening on the side of each supply / discharge port 31 that contacts the end cover 12 communicates with supply / discharge passages 42, 42 formed inside the end cover 12. The supply / discharge passages 42, 42 formed in the end cover 12 are connected to the hydraulic pump 2 or the oil tank 5 via the pipelines 3, 4 and the direction switching valve 1.

  The swash plate 17 is provided between the end wall portion 22 of the casing 11 and the cylinder block 14, and, as shown in FIG. 2, a flat sliding surface S inclined at a predetermined angle in a plane parallel to the XY plane. have. As described above, each piston shoe 33 slides in a circular shape while being pressed onto the sliding surface S as the cylinder block 14 rotates. In the present embodiment, a fixed capacity type in which the swash plate 17 is fixed to the end wall portion 22 as shown in FIG. 2 is applied. Note that a variable displacement type equipped with a swash plate tilting device that changes the tilt angle of the swash plate 17 can also be applied. In the case of the variable displacement type, it is possible to change the displacement of the motor by changing the inclination angle of the sliding surface S and changing the distance that the piston 15 reciprocates.

  In the hydraulic motor 10 having the above-described configuration, as shown in FIG. 1, oil from the hydraulic pump 2 is supplied to the cylinder hole 29 through one supply / discharge passage 42 and the supply / discharge port 31, while each cylinder hole 29 oil is discharged to the supply / discharge passage 42 through the other supply / discharge port 31 and returned to the oil tank 5. The piston 15 in the cylinder hole 29 supplied with oil presses the swash plate 17. A rotational force is generated by the force of the rotational direction component generated in the piston 15. This rotational force is transmitted to the rotary shaft 13 via the cylinder block 14 and rotates the rotary shaft 13.

  Next, the rotation sensor 50 provided in the hydraulic motor 10 described above and the detected portion 52 detected by the rotation sensor 50 will be described in detail.

  As shown in FIG. 1, a through hole 25 penetrating in the radial direction is formed on the rear end side of the casing 11 described above, and a rotation sensor 50 is attached to the through hole 25. In the present embodiment, a surface that is perpendicular to the rotation shaft 13 and includes the mounting portion 18 in FIG. 1 is considered, and the rotation sensor 50 is installed so as to include a part of the surface. The rotation sensor 50 detects the number of rotations of the cylinder block 14 within a predetermined time. The cylinder block 14 and the rotating shaft 13 rotate integrally, and the rotating shaft 13 and the fan 62 rotate integrally. Accordingly, the rotational speed of the cylinder block 14 is equal to the rotational speed of the fan 62.

  The rotation sensor 50 includes a detection unit 51 that detects a detected unit 52 provided on the outer peripheral surface of the cylinder block 14. The detection unit 51 is fixed to the casing 11 in a state where the detection unit 51 faces the detected unit 52 with a predetermined interval. The detection result by the detection unit 51 is transmitted to a calculation unit (not shown). The calculation unit calculates the rotation speed of the cylinder block 14 based on the detection result of the detection unit 51.

  As the rotation sensor 50, for example, an electromagnetic pickup type sensor using an MR element (magnetoresistance effect element) or a Hall element can be applied. The electromagnetic pickup type rotation sensor is a general sensor having a structure in which a coil is wound around a permanent magnet, and detects a change in magnetic flux between a detection unit and a detection target unit.

  As shown in FIG. 3, the detected portion 52 is a gear-shaped concavo-convex portion formed by cutting the concave portion 53 at regular intervals around the circumference of the outer peripheral surface of the cylinder block 14. The detected portion 52 is formed at a position corresponding to the position where the rotation sensor 50 is arranged, that is, at the rear end side of the cylinder block 14.

  When the cylinder block 14 rotates, the concave portion 53 and the convex portion 54 of the detected portion 52 pass through the position of the rotation sensor 50, thereby periodically changing the distance (magnetic field) between the detecting portion 51 and the detected portion 52. To change. The detection unit 51 of the rotation sensor 50 outputs the AC voltage generated by the magnetic field change as a signal, and transmits this signal to the calculation unit. The calculation unit shapes the AC voltage into pulses, counts the number of pulses, and calculates the rotation speed of the cylinder block 14 (that is, the rotation speed of the fan 62).

  The arrangement position of the rotation sensor 50 described above will be described in more detail. As shown in FIG. 1, in the present embodiment, the detection unit 51 of the rotation sensor 50 is arranged in the XZ plane.

  Here, the “XZ plane” is a surface including both the line on the sliding surface S of the swash plate 17 orthogonal to the axis 13a of the rotating shaft 13 and the axis 13a. That is, the “line on the sliding surface S of the swash plate 17 orthogonal to the axis 13a” is a line orthogonal to the line in the inclination angle direction of the sliding surface S of the swash plate 17. In other words, the “surface including both the line on the sliding surface S of the swash plate 17 orthogonal to the axis 13a and the axis 13a” is the line and axis in the direction of the inclination angle of the sliding surface S of the swash plate 17. It is a surface orthogonal to the surface (XY plane in FIG. 2) including both the core 13a.

  The reason why the detection unit 52 of the rotation sensor 50 is arranged in the XZ plane is as follows. As described above, the hydraulic motor 10 rotates the cylinder block while changing the position of the piston sliding in the cylinder holes arranged on the same circumference with time. For this reason, when the cylinder block 14 rotates, a swing in the Y direction occurs in the XY plane shown in FIG. Therefore, when the rotation sensor 50 is disposed in the XZ plane orthogonal to the XY plane, the rotation of the cylinder block 14 is hardly affected by the vibration in the XY direction. That is, the distance between the detected portion 52 formed on the outer peripheral surface of the cylinder block 14 and the detection portion 51 of the rotation sensor 50 is always kept substantially constant regardless of the swinging of the cylinder block 14. . The “plane including both the line on the sliding surface of the swash plate perpendicular to the axis of the rotating shaft and the axis” includes the XZ plane shown in FIG. 1 around the axis of the rotating shaft 13. The surface rotated about several degrees is also included.

  In addition, when the variable capacity type in which the inclination angle of the swash plate 17 can be changed is applied, the above-described XZ plane is the axis (not shown) of the swash plate rotation shaft that tilts the swash plate 17. A surface including both the axis 13a of the rotating shaft 13 is meant.

  Further, the rotating shaft 13 is supported on the proximal end side and the distal end side by bearings 24a and 24b, respectively. Therefore, the center portion between the proximal end side and the distal end side is the largest in the shake of the rotating shaft 13 due to the swirling rotation. Therefore, in the present embodiment, in order to minimize the influence of the shake of the rotating shaft 13, the detection unit 51 of the rotation sensor 50 is connected to the base end side of the rotating shaft 13, as shown in FIG. 11 is arranged on the rear end side.

  Here, as a guideline of the “rear end side of the casing”, the distance between the deepest portion 41 of the portion where the inner diameter of the cylinder hole 29 is the piston diameter in the axial direction of the cylinder block 14 and the rear end surface 28 of the cylinder block 14 is provided. It is a position opposite to the position.

  Corresponding to the arrangement position of the detection unit 51 described above, the detected unit 52 includes a deepest portion 41 where the inner diameter of the cylinder hole 29 is the piston diameter and the rear end of the cylinder block 14 in the axial direction of the cylinder block 14. It is formed between the side end faces 28. As shown in FIG. 1, since the dimension of the cylinder port 32 in the Z direction is smaller than the diameter dimension of the cylinder hole 29, the outer peripheral part of the formation position of the cylinder port 32 is larger than the outer peripheral part of the formation position of the cylinder hole 29. It is thick. When the detected portion 52 is formed using this thick portion, there are the following advantages.

  As shown in FIG. 1, the outer peripheral part of the formation position of the cylinder hole 29 is thin. For this reason, when the detected portion 52 is formed on the tip side of the cylinder block with respect to the position shown in FIG. 1, in order to ensure strength, the concave portion 53 is formed between the adjacent cylinder holes so as to avoid this thin portion. Need to form. In this case, the number of recesses 53 formed is the same as the number of cylinder holes 29. On the other hand, in the case where the detected portion 52 is provided in the above-described thick portion, the uneven portion can be continuously formed in a gear shape, so that it is easy to cut and is related to the number of cylinder holes 29. The recessed part 53 can be formed without.

  Further, when the fan driving device 60 shown in FIGS. 4 to 6 is driven, the fan 62 having a large shape rotates at the tip of the hydraulic motor 10, and therefore the tip of the hydraulic motor 10 is most likely to vibrate. On the other hand, since the base portion 65 is fixed, the vibration is small near the base portion 65, and the vibration increases as the distance from the base portion 65 increases. For this reason, when the hydraulic motor 10 is attached to the base 65, it is preferable to place the rotation sensor 50 as close to the base 65 as possible in order to minimize the vibration transmitted to the rotation sensor 50 when the hydraulic motor is driven. As described above, the hydraulic motor 10 is attached to the base portion 65 by inserting the casing 11 into the through hole 64 of the base portion 65 and affixing the attachment portion 18 to the back surface of the base portion 65 and bolting. Further, as described above, the rotation sensor 50 is installed in the casing 11 so as to include a part of a surface that is perpendicular to the rotation shaft 13 and includes the mounting portion 18. For this reason, when the hydraulic motor 10 is attached to the base 65, the rotation sensor 50 is disposed at a position close to the back surface of the base 65. Therefore, the vibration transmitted to the rotation sensor 50 when the hydraulic motor is driven can be minimized.

  Note that when the fan driving device 60 is driven, dust, mud, and the like are sucked together with air from the outside. These dust and mud pass through the radiator 80, the fan 62, and the opening 69 of the shroud 63. However, as shown in FIG. 6, the rear end side of the hydraulic motor 10 is located on the back surface side of the base portion 65 of the bracket 61 and both sides thereof are covered by the side wall portion 66. Therefore, the rotation sensor 50 is protected from dust and mud sucked from the outside.

  As described above, the fan driving device 60 according to the present embodiment provides the detected portion 52 on the outer peripheral surface of the cylinder block 14 of the hydraulic motor 10 that drives the fan 62 and detects the detected portion 52. The portion 51 is arranged in an XZ plane orthogonal to the XY plane. With the above configuration, the distance between the rotation sensor 50 and the detected portion 52 can be kept substantially constant regardless of the swing of the cylinder block 14 in the XY plane. As a result, it is possible to improve the accuracy of detecting the rotation speed of the cylinder block as compared with the conventional case, and to perform highly accurate fan control.

  Further, the fan drive device 60 of the present embodiment has a configuration in which the rotation sensor 50 is disposed on the rear end side of the casing 11 that is the base end side of the rotation shaft 13. By adopting the above-described configuration, it becomes difficult to be affected by the shaft shake accompanying the swirling rotation, so that the detection accuracy of the rotation speed of the cylinder block can be further improved.

  In addition, according to the fan drive device 60 of the present embodiment, the detected portion 52 includes the deepest portion 41 where the inner diameter of the cylinder hole 29 is the piston diameter in the axial direction of the cylinder block 14 and the cylinder block 14. By forming in the thick part between the rear end side end surface 28, cutting can be performed easily. In addition, since the number of recessed portions 53 can be increased regardless of the number of cylinder holes 29, the detection accuracy of the rotational speed of the cylinder block 14 can be further improved.

  Furthermore, according to the fan drive device 60 of the present embodiment, the hydraulic motor 10 is attached to the bracket 61 in a state where the rotation sensor 50 is brought close to the back surface of the base 65, so that when the hydraulic motor is driven, Since the vibration transmitted to the rotation sensor 50 can be suppressed to the minimum, the possibility of causing a failure due to the vibration of the rotation sensor can be reduced.

  In addition, according to the fan driving device 60 of the present embodiment, the hydraulic motor 10 is attached to the bracket 61 in a state where the rotation sensor 50 is positioned on the back surface side of the bracket 61, so that it can be externally applied. Intruding dust and mud can be prevented from adhering to the rotation sensor 50.

  In the above embodiment, the case where the hydraulic pump / motor of the present invention is applied to a fan drive device has been described. However, the present invention is not limited to these, and other drive devices or swash plate type hydraulic pumps are used. Can also be applied.

It is sectional drawing which shows schematic structure of the hydraulic motor applied to the fan drive device which is this Embodiment. It is AA sectional view taken on the line of the hydraulic motor shown in FIG. FIG. 3 is a cross-sectional view of the hydraulic motor shown in FIG. 1 taken along line BB. It is a rear view of the fan drive device which is this Embodiment. It is CC sectional view taken on the line of the fan drive device shown in FIG. FIG. 5 is a cross-sectional view of the fan drive device shown in FIG. It is sectional drawing which shows schematic structure of the conventional hydraulic pump motor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Directional switching valve 2 Hydraulic pump 3, 4 Pipe line 5 Oil tank 10 Swash plate type hydraulic motor 11 Casing 12 End cover 13 Rotating shaft 13a Shaft center 14 Cylinder block 15 Piston 16 Valve plate 17 Swash plate 18 Mounting part 21 Cylindrical part 22 End Wall part 23 Oil seal 24a, 24b Bearing 25 Through-hole 26 Spline 27 Front end face 28 Rear end face 29 Cylinder hole 31 Supply / exhaust port 32 Cylinder port 33 Piston shoe 34 Shoe retainer 35 Convex part 36 (Cylinder block) 36 Retainer guide 37 Spring 38 Seat 39 Pin 41 Cylinder hole deepest part 42 Supply / exhaust passage 50 Rotation sensor 51 Detection part 52 Detected part 53 Concave part 54 Convex part 60 Fan drive device 61 Bracket 62 Fan 63 Shroud 64 Through hole 65 Base part 66 Side wall part 67 fan boss 68 blade 69 opening 71,72 bolt 80 radiator

Claims (2)

A rotating shaft rotatably mounted in the casing; a cylinder block that rotates together with the rotating shaft; a plurality of pistons removably inserted into a plurality of cylinder holes formed in the cylinder block; and the rotation In the hydraulic pump motor having a swash plate provided in the casing so as to be inclined with respect to an axis and slidingly slidably contacting tip ends of the plurality of pistons,
A detected portion formed on the outer peripheral surface of the cylinder block;
A rotation sensor that is disposed on the casing in a state of facing the detected portion and includes a detection unit that detects the detected portion;
The detection unit of the rotation sensor
A hydraulic pump / motor which is disposed in a plane including both a line on a sliding surface of a swash plate perpendicular to the axis of the rotating shaft and the axis. The rotation sensor is
2. The hydraulic pump / motor according to claim 1, wherein the hydraulic pump / motor is provided at a position corresponding to a distance between a deepest portion of the cylinder hole and a rear end surface of the cylinder block in the axial direction of the cylinder block.

Images