JPH1077956A - Cam plate type axial piston pump - Google Patents

Abstract

PROBLEM TO BE SOLVED: To increase the load capacity of a bearing so as to make pressure high by providing a selector valve rotated around a fulcrum part of a cradle, and leading lubricating oil into a bearing part of a cradle only from a low pressure side circuit of a closed circuit. SOLUTION: A valve arm 16 is rotated around a rotary spool 17 as a pivot so as to constitute a selector valve V between the rotary spool 17 and a cradle 3. This selector valve V switches between the case of pressure oil in lubricating oil pores 15a, 15b being guided to lubricating oil guide holes 18a, 18b through a lubricating oil passage 17a in the rotary spool 17 and the case of this pressure oil being closed. With this constitution, in a circulating closed circuit, operating oil from a plunger and a shoe on the high pressure side is blocked, and operating oil from a plunger and a shoe positioned on the low pressure side is guided to lubricating parts 19, 20 of a bearing face between the cradle 3 and a cradle receiving face 5a through the lubricating oil pores 15a, 15b, the lubricating oil passage 17a and the lubricating oil guide holes 18a, 18b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a swash plate type axial piston pump and, more particularly, to a lubrication mechanism and a bearing mechanism for a cradle constituting a swash plate.

[0002]

2. Description of the Related Art Conventionally, there has been a method of forcibly lubricating a swash plate type axial piston pump by introducing pressure oil of a hydraulic closed circuit circulating between a suction side and a discharge side into a bearing portion of a cradle. (See, for example, Japanese Patent Application Laid-Open No.
However, in the case of the conventional configuration, since the high pressure on the discharge side of the closed circuit is directly introduced into the bearing, high noise is generated when high-pressure oil leaks into the case. .
A smaller cradle also reduces the supply of high pressure oil and improves noise, but has clogging and processing limitations.

[0003] Conventionally, the half metal on the rear surface of the cradle is fixed by bolts, rivets, or spring pins. When the cradle is fixed with a countersunk screw, a gap is generated between the cradle 3 and the half metal 4 due to the loosening of the screw, and the half metal is displaced. Further, there was a problem that the head of the countersunk screw protruded from the half metal surface and interfered with the cradle. Further, in the related art which is fixed by the spring pin, there is a problem that the pin is shifted or dropped because the pin is less likely to be caught during the assembling work. Further, there is a problem that it is difficult to control the height of the upper surface of the half metal 4 and the height of the spring pin.

When the cradle slides, it oscillates according to the discharge pressure. However, due to the pressure fluctuation that occurs when the plunger sliding on the cradle alternately discharges and sucks, the cradle moves. However, on the plane perpendicular to the axial direction, the rotational force from the plunger shoe acts, causing unstable behavior between the guides of the cradle cradle, resulting in an increase in noise of the hydraulic pump. Although measures have been taken to reduce the gap between the guides, there has been a problem that the management of the gap increases costs due to processing accuracy.

[0005] Further, when the central portion of the half metal is fixed by crimping with screws or rivets, the half metal is warped at the time of crimping and does not fit into the semi-cylindrical shape of the cradle receiving stand. As a result, a gap is generated between the cradle support 5 and the half metal, and a required bending stress acts on the crimping portion, resulting in breakage of the half metal. Fretting occurs due to the gap. In addition, since the cradle does not fit in the shape of the half cylinder, the behavior becomes unstable and high noise is generated.

Conventionally, a plurality of springs are arranged in parallel at one end of a cradle, or a non-linear spring is arranged at one end of a cradle to reduce the discharge amount of the pump in inverse proportion to the discharge pressure of the pump. I was doing it. However, in the case of such a conventional technique, pressure-
Due to the poor approximation of the flow characteristics, there was a problem that the engine horsepower could not be used effectively. In addition, the mechanism is complicated and the cost is high, and there is a problem that the swing center of the cradle 3 is worn or seizure occurs.

[0007]

SUMMARY OF THE INVENTION The present invention improves the configuration of the swash plate type axial piston pump P in order to solve the above-mentioned disadvantages of the prior art.

[0008]

The problem to be solved by the present invention is as described above. Next, means for solving the problem will be described. In the swash plate type axial piston pump, the pressure oil of the hydraulic closed circuit circulating between the suction side and the discharge side is supplied to the plunger 1 and the shoe 2.
And the cradle 3 is forcibly lubricated through the cradle 3 and provided with a switching valve V that rotates about the fulcrum of the cradle 3, and lubricates the cradle 3 only from the low pressure side circuit of the closed circuit. It is to introduce oil.

In the swash plate type axial piston pump provided with the cradle 3, the half metal 4 supporting the bearing surface of the cradle 3 is fixed by driving two pins into the cradle receiving portion. One of the two pins is used for positioning the half metal 4 in the circumferential direction and both sides, and the other is used for preventing the half metal 4 from coming off.

According to a third aspect of the present invention, in the swash plate type axial piston pump provided with the cradle 3, the bearing surface of the cradle 3 is supported by the half metal 4, and the cylindrical projection 11 is pressed on the back surface of the half metal 4. And press-fits the cylindrical projection 11 into a fitting hole 5b provided in the cradle receiving surface 5a to fix the half metal 4.

According to a fourth aspect of the present invention, in the swash plate type axial piston pump provided with the cradle 3, a pressing spring 6 for pressing the cradle 3 in one direction is provided in a cradle lateral guide portion of the cradle receiving base 5. is there.

According to a fifth aspect of the present invention, in the swash plate type axial piston pump provided with the cradle 3, the structure of the fixing portion for bringing the half metal 4 into contact with the cradle receiving stand 5 is such that both ends of the half metal 4 are interposed via plates. The plate is screwed, and a half metal 4
Is pressed against the cradle receiving stand 5.

According to a sixth aspect of the present invention, in the swash plate type axial piston pump, the cradle 3 is configured to be capable of swinging so as to arbitrarily control a discharge flow rate in accordance with a pump discharge pressure. Two or more points are provided on the back of the cradle 3, and the center of the cradle 3 is changed while the center of the cradle 3 is changed while the spring provided at one end of the cradle 3 and each swaying center are kept in balance. This enables lubrication of each swinging part.

[0014]

Next, an embodiment of the present invention will be described. FIG. 1 is a front partial cross-sectional view of a swash plate type axial piston pump of the present invention, an axial piston motor M, and a servo valve T for controlling rotation of a cradle of the swash plate type axial piston pump. FIG. 3 is a plan view of a plate-type axial piston pump and a portion of a charge pump CP disposed on an extension of a pump shaft 10 of the swash plate-type axial piston pump. FIG. FIG. 4 is an enlarged side view of the cradle 3 and the switching valve V. FIG. 5 is a method of fixing the half metal 4 provided on the cradle receiving stand 5. FIG. 6 shows the fixing pin 2 of the half metal 4
FIG. 7 is a side sectional view showing a structure in which a cylindrical projection 8 projects from the back surface of the half metal 4 and is fitted and fixed in a fitting hole 5 b of the cradle receiving stand 5. FIG. 8 is a drawing showing a configuration in which two cylindrical projections 8 are provided on the upper and lower sides.

In FIGS. 1 and 2, an swash plate type axial piston pump P is arranged at an upper stage, and an axial piston motor M is arranged at a lower stage. A servo valve T is provided on the left side of the swash plate type axial piston pump P. The internal spool 13 is switched by the operation of the servo valve T with a wire interlocked with an operation lever, or the supply of pilot pressure oil from a solenoid valve switched by a signal from a sensor, or the external servo piston 12 Moves up and down, and the servo piston 1
The cradle 3 which constitutes the swash plate type axial piston pump P moves up and down as the engaging pin 11 interlocked with 2 moves up and down.

As shown in FIG. 2, the swash plate type axial piston pump P and the axial piston motor M are both attached to one side of the center plate C, and the swash plate type axial piston pump P and the axial piston motor M are connected to each other. Servo valve T is installed inside HST case 14 to be covered.
Is configured. A swash plate type axial piston pump P is attached above the center plate C.
An axial piston motor M is attached to the lower part, and both of them are covered with an HST case 14. The HST
A charge pump CP is provided outside the case 14.

The hydraulic oil in the plunger chamber of the plunger 1 in FIG. 2 is introduced into the sliding surface of the cradle 3 through the small hole 7 of the shoe 2. As shown in FIG. 3, the surface of the cradle 3 on which the shoe 2 slides is provided on one of the high-pressure side surface and the low-pressure side surface which is branched right and left.
Lubricating oil small holes 15a and 15b are respectively opened.
The small lubricating oil holes 15a and 15b have a branch point at the center,
In the case of forward rotation, the lubricating oil small hole 15a is switched to the low pressure or high pressure side, and in the case of reverse rotation, the lubricating oil small hole 15b is switched. The switching between the forward rotation and the reverse rotation is performed by rotating the cradle 3 by the engagement pin 11 by the servo valve T, and this switching is detected by the valve engagement pin 21 and the valve arm 16. is there.

The valve engaging pin 21 is fixed to the cradle receiving table 5 side, and the valve arm 16 is fixed to a protruding end of a rotary spool 17 fitted inside the cradle 3. The switching valve V is formed between the rotary spool 17 and the cradle 3 by rotating the valve arm 16 using the rotary spool 17 as a pivot.
The swash plate type axial piston pump is switched between a case where the pressure oil a and 15b is guided to the lubrication oil guide holes 18a and 18b via the lubrication oil passage 17a in the rotary spool 17 and a case where the pressure oil is closed. , A closed hydraulic circuit that circulates between the discharge side and the suction side is configured. With this configuration, in the closed circuit that circulates the swash plate type axial piston pump P and the axial piston motor M, the hydraulic oil from the plunger 1 and the shoe 2 on the high pressure side is closed and the plunger 1 located on the low pressure side The hydraulic oil of the shoe and the shoe 2 is supplied from the small hole 7 to the small lubricating oil holes 15 a and 15 b and the lubricating oil passage 17.
a through the lubricating oil guide holes 18a and 18b, a lubricating portion 19 of the bearing surface between the cradle 3 and the cradle receiving surface 5a.
Guide to 20.

Next, a structure for fixing the half metal 4 to the cradle receiving surface 5a of the cradle receiving table 5 will be described with reference to FIGS. Half metal 4 with diameter 4
The small holes of 4.5 mm and 4.5 mm are opened, and the positioning of the half metal 4 is performed by the fixing pins 21 inserted into the holes of 4 mm.
The half metal 4 is prevented from coming off on the side surface of the 4.5 mm hole. With this configuration, even when the cradle 3 is not placed on the half metal 4, the half metal 4 does not come off the cradle receiving surface 5a. Further, since no extra stress is generated in the half metal 4, the durability performance can be improved. Half metal 4
Is almost completely fixed.

7 and 8, in a swash plate type axial piston pump provided with a cradle 3, a bearing surface of the cradle 3 is supported by a half metal 4, and a cylindrical projection 8 is provided on the back surface of the half metal 4. Is formed by pressing, and the cylindrical projection 8 is press-fitted into a fitting hole 5b provided in the cradle receiving surface 5a to fix the half metal 4. The cylindrical projection 8 is formed to project integrally from a part of the half metal 4 by press molding. Thereby, the machining of the seat surface of the countersunk screw on the half metal 4 becomes unnecessary.

FIG. 9 is a front view showing a structure in which a pressing spring 6 for pressing the cradle 3 in one direction is provided on a lateral guide portion of the cradle 3, FIG. 10 is a side view thereof, and FIG. FIG. 12 is a side sectional view and a front view showing a configuration in which the fixing plate 9 is provided with a spring action in a configuration in which both ends of the half metal 4 are screwed and fixed via a plate, and FIG.
A side sectional view and a front view showing a configuration in which the fixing plate 9 also serves to prevent the lateral displacement of the half metal 4;
14 is also a side sectional view and a front view showing an integral mounting structure of the fixing plate 9, FIG. 15 is a side sectional view and a front view showing the structure of the fixing plate 9, and FIG. FIG. 17 also illustrates a configuration in which the pressing spring for pressing the side surface of the cradle 3 is also used. FIG. 17 also shows an embodiment in which the fixing plate 9 also serves as the pressing spring for the side surface of the cradle 3, and FIG. The swing center of the cradle 3 is provided at two points on the back of each of the discharge and suction sides, and the spring provided at one end of the cradle 3 and each swing center maintain a balance.
FIG. 19 is a side view of a configuration in which the swing center changes in order to control the swing angle of the cradle 3, FIG. 19 is a drawing showing a pressure-flow rate curve when there are two swing centers, and FIG. FIG. 21 is a side view showing a configuration in which three points are provided, FIG. 21 is a drawing showing a pressure-flow rate curve when the rocking center is three points, and FIG. Side view showing the state of
FIG. 23 is a drawing showing a pressure-flow rate curve in the case of the inflection point A, FIG. 24 is a side view in the case of swinging about the inflection point B, and FIG. FIG. 26 is a diagram showing a pressure-flow rate curve, FIG. 26 is a side view showing the case where the oscillating motion is centered on the inflection point C, and FIG.

9, 10, and 11 disclose a configuration in which a pressing spring 6 that presses the cradle 3 in one direction is provided on a cradle lateral guide portion of the cradle receiving table 5. When the portion of the shoe 2 of the plunger 1 slides on the surface of the cradle 3 while rotating, the discharge pressure fluctuates, and the cradle 3 moves in a plane perpendicular to the axial direction as the plunger pressure fluctuates. Then, the rotational force from the plunger shoe 2 acts, and the behavior becomes unstable between the plunger shoe 2 and the cradle receiving surface 5a, and the noise of the swash plate type axial piston pump P increases. By pressing the side surface of the cradle 3 with the pressing spring 6 as in the present invention, the effect of the rotational force of the plunger shoe 2 is reduced, and the behavior of the cradle 3 is stabilized. The pressing spring 6 is constituted by an arc-shaped protruding pin whose tip is in contact with the side surface of the cradle 3 when embedded in the cradle receiving stand 5.

In the configuration shown in FIGS. 12 to 15,
There is disclosed a configuration in which a fixing plate 9 for fixing the half metal 4 is provided, and the fixing plate 9 is provided with a spring force for pressing and pressing the half metal 4. The fixing screws and screws at one end of the half metal 4 are loosened, and the ends of the half metal 4 are worn. In this case, the half metal 4 is fixed by the two fixing plates 9. In this configuration, the fixed plate 9 at one end is provided with a spring force, whereby unstable behavior due to the swing of the cradle 3 can be prevented. FIG.
In FIGS. 3 and 14, a part of the upper fixing plate 9 is configured to also serve as a pressing spring mechanism for urging the side guide surface of the half metal 4 toward the spring. Also in FIGS. 16 and 17, the half metal 4 is fixed to the cradle receiving table 5 by the upper and lower fixing plates 9, but is pressed from one end of the fixing plate 9 toward the side of the cradle 3. The structure which protruded the part of the spring 6 is illustrated.

FIGS. 18 to 27 show an embodiment in which the cradle 3 is provided with two or three swing centers and two or more swing centers so that the pressure-flow rate curve approximates the theoretical characteristics. It is illustrated. In this embodiment, inflection points A, B, and C constituted by bearing rollers as swinging members are provided on the rear surface of the cradle 3, and the swing center of the cradle 3 causes the swing center to be inflection point in order. It is configured to change from A to B to C. conventionally,
A method of arranging a plurality of balancing tilt springs 30 arranged at one end of the cradle 3 so that the pressure-flow rate curve approximates the theoretical choice and performs constant horsepower control as much as possible. A method of interposing a linear spring, a method of providing a spring and a link mechanism, and the like have been adopted, and constant horsepower control has been performed. In the configuration of the present invention, the inflection points A, B, and C can be simply configured by the bearing rollers, so that the cost can be reduced. That is, in FIGS. 18 to 27, in the swash plate type axial piston pump, in a configuration in which the cradle 3 is capable of swinging so as to arbitrarily control the discharge flow rate in accordance with the pump discharge pressure, the swing center of the cradle 3 is set. ,
Two or more points are provided on the back of each of the discharge and suction sides, and while the spring provided at one end of the cradle 3 and each rocking center are kept in balance, the rocking center changes in order to change the rocking angle of the cradle 3. The technology to control is disclosed.

FIG. 28 is a view showing a driving mechanism in which an auxiliary pump 31 is provided on a shaft of a conventional swash plate type axial piston pump P. FIG. 29 is a diagram showing an auxiliary gear pump 33 provided on a pump mount 35 provided along with the pump shaft 10. FIG. 30 is a sectional view showing a configuration in which the pump shaft 10 is arranged in parallel with the input shaft 36, and the speed increasing gear pump 32 is arranged between the input shaft 36 and the pump shaft 10. It is. Conventionally, two pumps or three pumps are provided on the extension of the pump shaft 10 in accordance with the specifications of the working machine. In such a conventional configuration, the total length of the pump shaft 10 and the swash plate type axial piston pump P is long. In addition, it is necessary to change the pump capacity according to the specifications of the working machine, and there has been a problem that the number of pumps that have already been used increases. As in this configuration, the pump shaft 10
By configuring the gear pump in parallel with the above, it is possible to set an arbitrary discharge amount by changing the rotation speed of the pump input shaft even when the specifications of the working machine are different. In addition, since the auxiliary pump is built in the pump mount 35, the total length of the pump is shortened.

[0026]

As described above, the present invention has the following advantages. In the swash plate type axial piston pump, the pressure oil of the closed circuit of the HST type hydraulic transmission is forcibly lubricated to the bearing portion of the cradle 3 through the plunger 1, the shoe 2, and the cradle 3, A switching valve V that rotates around the fulcrum of the cradle 3 is provided, and lubricating oil is introduced into the bearing of the cradle 3 only from the low-pressure side circuit of the closed circuit. Since the working oil on the side can be lubricated, the load capacity of the bearing increases and the swash plate type axial piston pump P can be pressurized. Further, the resistance of the cradle 3 can be reduced, and noise and vibration generated from the cradle 3 can be reduced. Also, the reduction of the swing resistance leads to the reduction of the hysteresis of the operation force.

In the swash plate type axial piston pump having the cradle 3, the fixing of the half metal 4 supporting the bearing surface of the cradle 3 is performed by driving two pins into the cradle receiving portion. One of the two pins is used to position the half metal 4 in the circumferential direction and both sides, and the other pin is used to prevent the half metal 4 from coming off. Therefore, the cradle 3 is not placed on the half metal 4. Even in this state, the half metal 4 did not come off. Further, no extra stress is generated in the half metal 4, and the half metal 4 can be completely fixed.

According to a third aspect of the present invention, in the swash plate type axial piston pump provided with the cradle 3, the bearing surface of the cradle 3 is supported by the half metal 4, and the cylindrical projection 8 is pressed on the back surface of the half metal 4. The cylindrical projection 8 is press-fitted into a fitting hole 5b provided in the cradle receiving surface 5a to fix the half metal 4, so that the half metal 4 and the cylindrical projection 8 are integrated. Since a press screw can be used, no separate flat head screw or screw is required, and the management of the seat surface of the flat head screw and the management of the protrusion of the flat head screw are unnecessary. Further, since the cylindrical projection 8 has an elastic force, it becomes difficult to come out when it is fitted into the fitting hole 5b.

According to a fourth aspect of the present invention, in the swash plate type axial piston pump provided with the cradle 3, the cradle 3 is provided on the cradle lateral guide portion of the cradle receiving stand 5.
The cradle 3 is always pressed against the guide surface of the cradle receiving stand 5 by the pressing spring 6 because the pressing spring 6 presses the cradle 3 in one direction. The effect of the rotational force due to the pressure fluctuation of the plunger 1 is reduced, and the behavior of the cradle 3 is stabilized.

In the swash plate type axial piston pump provided with the cradle 3, the structure of the fixed portion for bringing the half metal 4 into contact with the cradle receiving stand 5 is such that both ends of the half metal 4 are interposed via plates. The plate is screwed, and the plate at one end is provided with a spring action to press the half metal 4 against the cradle cradle 5, so that one end of the half metal 4 is pressed by using spring steel having a spring action. Therefore, even if the screw at the other end is loosened or the methane end is worn, the half metal 4 always fits near the semi-cylindrical hole shape of the cradle 3 so that the swinging behavior of the cradle 3 should be stabilized. Can be done. Also, even if the pressing load from the cradle 3 fluctuates, the stress concentration portion due to the hole processing is eliminated on the surface of the half metal 4, so that the strength of the half metal 4 is improved, and the pressure receiving area of the half metal 4 is increased, As compared with the half metal 4 with holes, the size is reduced and the cost is reduced.

According to a sixth aspect of the present invention, in the swash plate type axial piston pump, the cradle 3 is capable of oscillating so as to arbitrarily control a discharge flow rate in accordance with a pump discharge pressure. Two or more points are provided on the back of each of the discharge and suction sides, and while the spring provided at one end of the cradle 3 and each rocking center are balanced, the rocking center changes in order, and the rocking angle of the cradle 3 is changed. Since the control is performed, the pressure-flow rate curve can be approximated to the theoretical characteristic curve, and constant horsepower control can be performed. Further, since each swing center moves according to the discharge gripping force of the pump, the swing portion is always lubricated with the operating oil in the pump casing, so that forced lubrication is unnecessary. Further, the amount of displacement of the spring due to the movement of the swash plate is reduced, the stress amplitude of the spring is reduced, and the durability is improved.

[Brief description of the drawings]

FIG. 1 shows a swash plate type axial piston pump of the present invention;
Servo valve T for rotationally controlling an axial piston motor M and a cradle of the swash plate type axial piston pump
Partial front sectional view of a portion.

FIG. 2 is a plan view of a swash plate type axial piston pump and a charge pump CP disposed on an extension of a pump shaft 10 of the swash plate type axial piston pump.

FIGS. 3A and 3B are a front view and a side cross-sectional view illustrating a configuration of a switching valve V that is rotated on the cradle receiving stand 5 and is switched by the rotation of the cradle 3. FIGS.

FIG. 4 is an enlarged side view of a cradle 3 and a switching valve V;

FIG. 5 is a front view showing a method of fixing a half metal 4 provided on a cradle receiving stand 5;

FIG. 6 is a side sectional view showing a state where the half metal 4 is fixed by the fixing pins 21 and 22;

FIGS. 7A and 7B are a side sectional view and a front view showing a structure in which a cylindrical projection 8 projects from the back surface of the half metal 4 and is fitted and fixed in a fitting hole 5b of a cradle receiving stand 5;

FIG. 8 is a drawing showing a configuration in which two cylindrical projections 8 are provided at the top and bottom.

FIG. 9 shows the cradle 3 on the lateral guide portion
FIG. 4 is a front view showing a configuration in which a pressing spring 6 that presses the head in one direction is provided.

FIG. 10 is a side view of FIG. 9;

FIG. 11 is an enlarged sectional view of a portion of the pressing spring 6;

FIGS. 12A and 12B are a side cross-sectional view and a front view showing a configuration in which the fixing plate 9 has a spring action in a configuration in which both ends of the half metal 4 are screwed and fixed via a plate.

FIG. 13 is a side sectional view and a front view showing a configuration in which the fixing plate 9 also serves to prevent the half metal 4 from shifting in the horizontal direction.

14A and 14B are a side sectional view and a front view showing an integrated mounting structure of the fixing plate 9;

FIG. 15 is a side sectional view and a front view showing the configuration of the fixing plate 9;

FIG. 16 is a drawing showing a configuration in which both the role of fixing the half metal 4 by the fixing plate 9 and the role of a pressing spring that presses the side surface of the cradle 3 are used.

FIG. 17 is a view showing an embodiment in which the fixing plate 9 also serves as a pressing spring on the side surface of the cradle 3.

FIG. 18 shows two pivot centers of the cradle 3 provided on the back of each of the discharge and suction sides. The spring provided at one end of the cradle 3 and each pivot center maintain a balance, and the pivot centers are sequentially determined. The side view of the structure which changes and controls the rocking angle of the cradle 3.

FIG. 19 is a drawing showing a pressure-flow rate curve when there are two swing centers.

FIG. 20 is a side view showing a configuration in a case where three swing centers are provided.

FIG. 21 is a drawing showing a pressure-flow rate curve when the swing center is at three points.

FIG. 22 is a side view showing a state of swinging about a first inflection point A;

FIG. 23 is a drawing showing a pressure-flow rate curve in the case of an inflection point A;

FIG. 24 is a side view in the case of swinging about an inflection point B.

FIG. 25 is a drawing showing a pressure-flow rate curve in the case of an inflection point B;

FIG. 26 is a side view in the case of swinging about the inflection point C.

FIG. 27 is a drawing showing a pressure-flow rate curve in the case of an inflection point C;

FIG. 28 is a view showing a drive mechanism in which an auxiliary pump 31 is provided on a shaft of a conventional swash plate type axial piston pump P.

FIG. 29 shows a pump mount 35 attached to the pump shaft 10.
Sectional drawing which shows the structure which attached the auxiliary gear pump 33 to the part.

30 is a drawing showing a configuration in which the pump shaft 10 is arranged in parallel with the input shaft 36, and the speed increasing gear pump 32 is arranged between the input shaft 36 and the pump shaft 10. FIG.

[Description of Signs] 1 Plunger 2 Shoe 3 Cradle 4 Half metal 5 Cradle receiving stand 5a Cradle receiving surface 6 Press spring 7 Small hole 8 Cylindrical projection 9 Fixing plate 10 Pump shaft 11 Cylindrical projection 12 Servo piston 13 Spool

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Yasuhisa Mochizuki 1-32 Chaya-cho, Kita-ku, Osaka, Osaka Inside Yanmar Diesel Corporation (72) Inventor Norihiko Sakamoto 1-32, Chaya-cho, Kita-ku, Osaka, Osaka Inside Yanmar Diesel Co., Ltd. (72) Koji Sakata, inventor 1-32 Chaya-cho, Kita-ku, Osaka, Osaka Prefecture Inside Yanmar Diesel Co., Ltd. (72) Kengo Sasahara 1-32, Chaya-cho, Kita-ku, Osaka, Osaka Inside the corporation

Claims (6)

[Claims] In a swash plate type axial piston pump, pressure oil of a hydraulic closed circuit circulating between a suction side and a discharge side is forcibly lubricated to a bearing portion of a cradle through a plunger, a shoe and a cradle. A swash plate type axial valve, wherein a switching valve V which rotates about a fulcrum of the cradle 3 is provided, and lubricating oil is introduced into the bearing of the cradle 3 only from the low pressure side circuit of the closed circuit. Piston pump. 2. In a swash plate type axial piston pump provided with a cradle 3, a half metal 4 supporting a bearing surface of the cradle 3 is fixed by driving two pins into a cradle receiving portion. A swash plate type axial piston pump characterized in that one of the pins is used to position the half metal 4 in the circumferential direction and both sides, and the other is used to prevent the half metal 4 from coming off. 3. A swash plate type axial piston pump having a cradle 3, wherein a bearing surface of the cradle 3 is supported by a half metal 4, and a cylindrical projection 8 is formed on a back surface of the half metal 4 by a press. A swash plate type axial piston pump characterized in that the cylindrical projection 8 is press-fitted into a fitting hole 5b provided in a cradle receiving surface 5a to fix the half metal 4. 4. A swash plate type axial piston pump provided with a cradle 3, wherein a pressing spring 6 for pressing the cradle 3 in one direction is provided on a cradle lateral guide portion of the cradle receiving stand 5. Plate type axial piston pump. 5. A swash plate type axial piston pump having a cradle 3, wherein a fixing portion for contacting the half metal 4 with the cradle receiving base 5 is screwed at both ends of the half metal 4 via a plate. A swash plate type axial piston pump, wherein the plate at one end is provided with a spring action for pressing the half metal 4 against the cradle receiving stand 5. 6. A swash plate type axial piston pump, wherein the cradle 3 is capable of swinging so as to arbitrarily control a discharge flow rate according to a pump discharge pressure. The swing center of the cradle 3 is controlled by sequentially changing the swing center while maintaining the balance between the spring 30 provided at one end of the cradle 3 and each swing center. Swash plate type axial piston pump.