JP2003239853A - Hydraulic pump - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce a production cost and the number of part items as a whole even when an additional pump is attached. <P>SOLUTION: A pump housing case 33 is integrally formed with a rear casing 32 of a casing 31 with a same material. The additional pump 34 comprising a gear pump is housed in the pump housing case 33. A driving shaft 34A of a driving gear 34B is spline-coupled to a rotating shaft 10, and the additional pump 34 is driven with the usage of rotating force of the rotating shaft 10. A rotation sensor 41 is provided on a position adjacent to a driven gear 34D in the pump housing case 33. The rotation sensor 41 detects a rotational frequency of the driven gear 34D (the rotating shaft 10). <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic pump preferably used as a hydraulic power source for construction machines such as hydraulic excavators or industrial machines.

[0002]

2. Description of the Related Art A tandem type swash plate type hydraulic pump will be described as an example of a conventional hydraulic pump with reference to FIGS. 6 and 7. FIG.

Reference numeral 1 denotes a casing which forms an outer shell of a tandem type swash plate type hydraulic pump. The casing 1 has a stepped cylindrical casing body 2, a front casing 3 for covering the front side of the casing body 2, and a casing. The rear casing 4 covers the rear side of the main body 2. Also,
The casing body 2 is formed substantially symmetrically on both sides in the axial direction,
The rear casing 4 side of the casing body 2 has a cylindrical portion 5A.
At the same time, the front casing 3 side is a cylinder portion 5B, and the cylinder portion 5A, 5B is a partition wall portion 6 separating the inside of the casing body 2.

A suction passage 7 and discharge passages 8A and 8B are provided in the partition wall portion 6, and the suction passage 7 is provided with a hydraulic oil tank (when operating first and second pump units 15A and 15B, which will be described later). The hydraulic fluid is sucked from (not shown), and the discharge passages 8A and 8B are connected to the first and second pump units 15A and 1A.
The hydraulic oil discharged from 5B is separated into hydraulic equipment (not shown).
Is to be supplied to.

Reference numeral 9A denotes a swash plate support member fitted and provided in the rear casing 4, and the swash plate support member 9A supports a swash plate 23A described later in a tiltable manner. Further, 9B is a swash plate support member fitted and provided in the front casing 3, and the swash plate support member 9B supports a swash plate 23B described later in a tiltable manner.

Reference numeral 10 denotes a first rotary shaft which is located on the rear side in the casing 1 and extends coaxially with a second rotary shaft 13 which will be described later. The first rotary shaft 10 has one end portion. A connecting hole portion 10A is provided in the connecting hole portion 10A, and a drive shaft 25B described later is spline-connected to the connecting hole portion 10A. A connecting hole 10B is also provided at the other end of the first rotating shaft 10, and one end of a second rotating shaft 13 described later is spline-connected to the connecting hole 10B.

One end of the first rotating shaft 10 is rotatably supported by the partition wall 6 of the casing body 2 via a bearing 11, and the other end of the first rotating shaft 10 is supported by a swash plate supporting member 9A, which will be described later.
It is rotatably supported via 2A. The axially intermediate portion of the first rotary shaft 10 is spline-coupled to the cylinder block 18A.

Reference numeral 13 denotes a second rotary shaft which is located on the front side in the casing 1 and which is provided by axially extending the central portion of the casing 1. One end of the second rotary shaft 13 is an engine. Etc. are connected to the drive source (not shown) side. Also,
One end of the second rotary shaft 13 is rotatably supported by the front casing 3 via a bearing 12B, and the other end of the second rotary shaft 13 is rotatably supported by a partition wall 6 of the casing body 2 via a bearing 14. Further, the axially intermediate portion of the second rotary shaft 13 is spline-coupled to a cylinder block 18B described later.

As described above, the first rotary shaft 10 and the second rotary shaft 13 are integrally connected to each other, whereby the second rotary shaft 13 is rotationally driven by the drive source, so that the first rotary shaft 13 is rotated. Rotate the rotary shaft 10 to rotate the cylinder block 18A,
18B is rotated in synchronization.

The casings 1 and 15A and 15B are paired.
The 1st, 2nd pump unit provided in the inside is shown. Here, the first and second pump units 15A, 15
Since B has the same configuration, only the configuration of the first pump unit 15A will be described below, and the configuration of the second pump unit 15B will be described below.
A component corresponding to A is given a reference sign “B” and its description is omitted.

Reference numeral 16A denotes a disc-shaped valve plate located in the cylindrical portion 5A and fixed to the partition wall portion 6, and the partition wall portion 6 is provided on the valve plate 16A.
Eyebrow-shaped switching ports 17A, 17A are formed to communicate with the suction passage 7 and the discharge passage 8A.

Reference numeral 18A is a cylinder block disposed in the cylindrical portion 5A of the casing body 2, and the cylinder block 1
8A is spline-coupled with the first rotating shaft 10 to
Rotates integrally with the rotating shaft 10 of. The other end surface of the cylinder block 18A is slidably attached to the valve plate 16A.

19A, 19A, ... Are cylinder blocks 1
8A is a plurality of cylinders formed at equal intervals in the circumferential direction around the first rotation shaft 10 and in the axial direction. Each cylinder 19A has a communication port 20A that opens to the other end surface of the cylinder block 18A. Through the switching ports 17A, 17A of the valve plate 16A.

21A, 21A, ... Are pistons 22A, 22A, which are reciprocally inserted in the respective cylinders 19A.
Is a shoe swingably connected to the projecting end side of each piston 21A, and each shoe 22A moves on a swash plate 23A described later when each piston 21A reciprocates in each cylinder 19A. It slides.

Reference numeral 23A denotes a swash plate which is tiltably provided in the cylindrical portion 5A of the casing body 2 so as to face the cylinder block 18A. The swash plate 23A is attached to the rear casing 4 and is a swash plate support member 9A. It is supported so that it can be tilted. Then, the swash plate 23A slides and guides each shoe 22A while the cylinder block 18A rotates, so that each piston 21A is most intruded into the cylinder 19A at the top dead center and the bottom dead most protruding from the cylinder 19A. It reciprocates between points. Also, the swash plate 23A is
The tilt angle is changed by being pressed by the tilt piston 24A, and the stroke amount of each piston 21A is appropriately adjusted to variably control the capacity of the first pump unit 15A.

Reference numeral 25 denotes an additional pump which is attached to the rear casing 4 and which is prepared as a detachable separate member. The additional pump 25 is manufactured as a completed product separately from the tandem hydraulic pump. Here, the additional pump 25 is
The drive gear 25C housed in the casing 25A and attached to the drive shaft 25B and the driven gear 25E attached to the driven shaft 25D constitute an additional pump.

Further, the casing 25A of the additional pump 25
Are integrally attached to the rear casing 4 by a plurality of bolts 26. The drive shaft 25B of the additional pump 25 is spline-coupled to the connection hole portion 10A of the first rotary shaft 10 to rotate integrally with the first rotary shaft 10 and rotationally drive the drive gear 25C. is there.

The tandem type swash plate type hydraulic pump according to the prior art has the above-mentioned structure. First, when the first and second rotary shafts 10 and 13 are rotationally driven by a drive source such as an engine, 2 pump units 15A, 15
The cylinder blocks 18A and 18B forming B rotate in synchronization.

As a result, the first additional pump unit 1
In 5A, each piston 21A provided with each shoe 22A slidingly contacting the swash plate 23A reciprocates in the cylinder 19A of the cylinder block 18A, and the reciprocating motion of this piston 21A causes the hydraulic oil sucked from the suction passage 7 to be compressed. Is discharged to the discharge passage 8A, and this pressure oil is supplied to the hydraulic equipment connected to the discharge passage 8A.

On the other hand, in the second additional pump unit 15B, each piston 21B provided with each shoe 22B slidably contacting the swash plate 23B has the cylinder 19 of the cylinder block 18B.
It reciprocates in B, and by the reciprocation of this piston 21B,
The hydraulic fluid sucked from the suction passage 7 is used as pressure oil, and the discharge passage 8 is used.
B is discharged to B, and this pressure oil is supplied to the hydraulic equipment connected to the discharge passage 8B.

During operation of such a hydraulic pump, the additional pump 25 is driven by the first and second rotary shafts 10 and 13 to discharge the oil liquid sucked from the suction port, for example, the flow rate of the hydraulic pump. It functions as a hydraulic source for control and a hydraulic source for operating valves of hydraulic excavators.

[0022]

In the tandem type swash plate hydraulic pump according to the above-mentioned conventional technique, an additional pump 25, which is a member separate from the rear casing 4, is purchased as a completed product from a supplier, and the additional pump 25 is used. The rear casing 4 is assembled on the outer surface of the rear casing 4 by using bolts 26 and the like.

Therefore, a new casing 25A is required separately from the rear casing 4, which causes a problem of high manufacturing cost. Further, not only is it necessary to provide a sealing member such as an O-ring between the rear casing 4 and the casing 25A, but also a large number of bolts 26 and the like are required, which increases the number of parts as a whole.

The present invention has been made in view of the above-mentioned problems of the prior art, and an object of the present invention is to reduce the manufacturing cost and the total number of parts even when an additional pump is mounted. The purpose is to provide a hydraulic pump.

[0025]

In order to solve the above-mentioned problems, a hydraulic pump according to the present invention is provided with a casing and an axially extending portion in the casing, and one side in the axial direction is connected to a drive source. A rotary shaft, a pump unit located in the casing and connected to the rotary shaft, and an additional pump located on the opposite side to the drive source in the axial direction and driven by the rotary shaft. There is.

A feature of the structure adopted by the invention of claim 1 is that the casing includes a cylindrical casing body for accommodating a pump unit therein, and a lid body provided on an end side of the casing body. The case for accommodating the additional pump is integrally formed of the same member as the lid body.

With this configuration, the case for accommodating the additional pump can be integrally formed with the lid body by the same member, so that it is not necessary to form the case by a separate member from the lid body, and a mounting member such as a bolt, A seal member such as an O-ring can be dispensed with.

According to the invention of claim 2, the additional pump is
It is an additional pump driven by a rotating shaft. With this configuration, by driving the additional pump by the rotating shaft, the oil liquid sucked into the additional pump can be smoothly discharged to the outside.

Further, in the invention of claim 3, the additional pump is provided with a rotation speed detecting device for detecting the rotation speed of the drive gear or the driven gear of the additional pump. With this configuration, it is possible to detect the rotation speed of the drive gear or the driven gear integrated with the rotation shaft by using the rotation speed detection device.

[0030]

BEST MODE FOR CARRYING OUT THE INVENTION A swash plate hydraulic pump according to an embodiment of the present invention will be described below in detail with reference to the accompanying drawings, taking as an example a case where the swash plate hydraulic pump is applied to a tandem type swash plate hydraulic pump. In addition, in the present embodiment, the same components as those of the above-described conventional technique are designated by the same reference numerals, and the description thereof will be omitted. Further, among the casing main body, the front casing, and the rear casing which form the casing, only the rear casing is different, and therefore, the rear casing will be described with reference numerals different from those of the conventional technique.

Reference numeral 31 denotes a casing according to this embodiment,
The casing 31 is similar to the above-mentioned conventional art,
A casing main body 2, a rear casing 32 as a lid detachably provided at an open end of a cylindrical portion 2A located on the rear side of the casing main body 2, and a front casing 3 for covering the front side of the casing main body 2. (Not shown).

Further, on the rear side of the rear casing 32, which is the side opposite to the later-described pump housing case 33, the first fitting groove 32A into which the swash plate supporting member 9A is fitted, and the fitting groove are formed. A second fitting groove 32B, which is located substantially at the center of 32A and into which a pressing plate 42 described later is fitted, is provided.

Reference numeral 33 denotes a pump housing case formed integrally with the rear casing 32 so as to project in the axial direction substantially in the center thereof. The pump housing case 33 is formed by casting or the like as shown in FIGS. It is integrally formed with the same member as 32. Then, the pump housing case 33
Is formed as a tubular body having an oval cross section, and an additional pump 34 described later is housed inside. Further, the pump housing case 33 is provided with a sensor mounting hole 33A for mounting a later-described rotation sensor, and the sensor mounting hole 33A is formed as a screw hole.

Reference numeral 34 denotes an additional pump arranged in the pump housing case 33. The additional pump 34 is the first rotary shaft 1
Drive gear 3 having a drive shaft 34A that is spline-coupled to the connecting hole portion 10A of 0 and is rotationally driven integrally with the rotary shaft 10.
4B and a driven gear 34D that has a driven shaft 34C and that meshes with the drive gear 34B.

Further, in the pump housing case 33, a pair of side plates 35, 35, which are arranged so as to face each other so as to sandwich the drive gear 34B from both the front and rear sides, are fitted and provided. A sleeve bearing 36 is provided on the inner peripheral side of each side plate 35.
Is fitted and rotatably supports the drive shaft 34A in the sleeve bearing 36.

Further, in the pump housing case 33, a pair of other side plates 37, 37 which are arranged to face each other so as to sandwich the driven gear 34D from both the front and rear sides, are provided so as to be fitted. A sleeve bearing 38 is fitted on the inner peripheral side of each side plate 37, and the driven shaft 34 is fitted in the sleeve bearing 38.
C is rotatably supported. And the additional pump 34
The driven gear 34D rotates following the rotation of the drive gear 34B to discharge the oil liquid sucked from the suction port 39 to the outside from the discharge port 40.

Reference numeral 41 denotes a rotation sensor which is screwed into the pump housing case 33 and serves as a rotation speed detecting device.
In No. 1, the detection unit 41A on the front end side is arranged at a position close to the driven gear 34D. Then, the rotation sensor 41 is
It is configured as an electromagnetic pickup including a magnet, a core member attached to the magnet, and a coil (none of which is shown) wound around the outer periphery of the core member.

The rotation sensor 41 is driven by the driven gear 34.
The rotation of D causes the driven gear 34D to approach and separate from the detection portion 41A (the tip of the core member), thereby generating an output voltage corresponding to the driven gear 34D, and using this output voltage as a detection signal from the lead wire 41B to the controller. (Not shown).

Reference numeral 42 designates a holding plate fitted into the fitting groove 32B of the rear casing 32.
Are formed in an oval shape as shown in FIG. Also,
The holding plate 42 is provided with an insertion hole 42A through which the drive shaft 34A of the drive gear 34B is inserted. And
The holding plate 42 is a side plate 35, 37 of the additional pump 34,
The additional pump 34 is housed in the pump housing case 33 by abutting on the driven shaft 34C.

The tandem type swash plate type hydraulic pump according to the present embodiment has the above-mentioned structure, and its basic operation is not particularly different from that of the prior art.

However, in the present embodiment, the additional pump 3
Since 4 is integrally formed in the rear casing 32 by casting with the same member, it is necessary to separately manufacture the tandem type swash plate type hydraulic pump including the casing 25A like the additional pump 25 described in the prior art as a completed product. Disappears.

Therefore, it is not necessary to specially provide a seal member such as an O-ring between the pump housing case 33 and the rear casing 32, and the pump housing case 33 is attached to the rear casing 32 using a large number of bolts and the like. It is not necessary, the total number of parts can be reduced, and the manufacturing cost can be reduced.

Further, the axial length of the entire hydraulic pump including the pump housing case 33 can be made shorter than the axial length of the entire hydraulic pump including the additional pump according to the prior art. Space can be easily secured, and layout design of the hydraulic pump can be easily performed.

Further, since the rotation sensor 41 is provided at the tooth tip of the additional pump 34 in order to detect the rotation speed of the rotary shaft 10, the rotation speed of the rotary shaft 10 is detected using the rotation sensor. For example, it is not necessary to provide a plurality of concavo-convex grooves or the like on the outer peripheral side of the cylinder block 18A so as to be spaced apart in the circumferential direction, and this can reduce the processing man-hours of the hydraulic pump and reduce the processing cost.

Further, since the entire rear casing 32 including the pump housing case 33 is formed by casting, the suction port 39 and the discharge port 40 of the additional pump 34 can be freely designed by using the core, and the rotation sensor The degree of freedom of the mounting position of 41 can be expanded.

In the embodiment, the case where the additional pump 34 has the front and rear side plates 35, 35 and the front and rear side plates 37, 37 has been described as an example, but the present invention is not limited to this. Without being limited to this, for example, the front side plate 35 and the front side plate 37 may be integrally formed to form one front side plate. Further, similarly to this, the front side plate 35 and the rear side plate 37 may be integrally formed so that the rear side plate is one.

Although the rotation sensor 41 is arranged in the vicinity of the driven gear 34D, the present invention is not limited to this, and the rotation sensor may be arranged in the vicinity of the drive gear.

Further, in the embodiments, the configuration in which the gear pump is used as the additional pump has been described, but the present invention is not limited to this, and can be applied to other pumps such as a trochoid pump and a vane pump.

Further, although the tandem type swash plate type hydraulic pump has been described as an example of the swash plate type hydraulic pump in the embodiment, the present invention is not limited to this, and for example, one pump unit in a casing. The present invention can be applied to a single type swash plate type hydraulic pump provided with, and also to a hydraulic pump provided with a pump unit of another type such as a radial piston type hydraulic pump.

Further, in the embodiment, the rotation sensor 41
As an example, an electromagnetic pickup coil has been exemplified.
It may be configured as another electromagnetic rotation sensor using a magnetoresistive element, a Hall element, or the like.

[0051]

As described in detail above, according to the first aspect of the invention, the casing has a cylindrical casing main body for accommodating the pump unit therein, and a lid provided on the end side of the casing main body. Since the case for accommodating the additional pump is integrally formed by the same member as the lid body, it is not necessary to form the case by a separate member from the lid body, and it is necessary to provide a sealing member such as an O-ring. The number of parts can be reduced and the manufacturing cost can be reduced.

The invention according to claim 2 further comprises an additional pump,
Since the additional pump is driven by the rotary shaft, the additional pump can be driven by utilizing the rotation of the rotary shaft, and the oil liquid sucked into the additional pump can be smoothly discharged to the outside.

Further, according to the invention of claim 3, since the additional pump is provided with the rotation speed detecting device for detecting the rotation speed of the drive gear or the driven gear of the additional pump, the rotation speed detecting device is used for rotation. It is possible to detect the rotational speed of the drive gear or the driven gear that is integrated with the shaft.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional view showing a rear casing, an additional pump and the like of a tandem type swash plate type hydraulic pump according to an embodiment of the present invention.

FIG. 2 is a side view of the rear casing when it is contracted from the left side in FIG.

FIG. 3 is a cross-sectional view of the additional pump as viewed in the direction of arrows III-III in FIG.

FIG. 4 is an enlarged cross-sectional view of essential parts showing a driven gear, a rotation sensor and the like in FIG.

FIG. 5 is a plan view showing the holding plate in an enlarged manner from the direction of the arrow VV in FIG.

FIG. 6 is a vertical cross-sectional view showing a tandem type swash plate type hydraulic pump according to a conventional technique.

FIG. 7 is a partially enlarged sectional view showing a rear casing, an additional pump and the like in FIG. 6 in an enlarged manner.

[Explanation of symbols]

2 Casing body 31 casing 32 Rear casing (lid) 33 Pump storage case (case) 34 Additional pump 34B drive gear 34D driven gear 39 Suction port 40 outlets 41 Rotation sensor 41A detector 41B lead wire

   ─────────────────────────────────────────────────── ─── Continued front page    F term (reference) 3H070 AA01 BB05 BB22 CC31 CC35                       DD05 DD91 DD96                 3H071 BB01 BB12 BB14 CC31 CC34                       DD82 DD84

Claims (3)

[Claims] 1. A casing, a rotating shaft extending in the casing in the axial direction and having one axial side connected to a drive source, and a pump located in the casing and connected to the rotating shaft. In a hydraulic pump including a unit and an additional pump that is located axially opposite to the drive source and is driven by the rotary shaft, the casing is a tubular casing that accommodates the pump unit therein. A hydraulic pump comprising a main body and a lid provided on an end side of the casing main body, and a case accommodating the additional pump is integrally formed by the same member as the lid. 2. The hydraulic pump according to claim 1, wherein the additional pump is an additional pump driven by a rotary shaft. 3. The hydraulic pump according to claim 2, wherein the additional pump is provided with a rotation speed detection device that detects a rotation speed of a drive gear or a driven gear of the additional pump.