JP2004239269A - Two-throw gear pump or motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a compact two-throw gear pump or motor which is utilized for a hydraulic appliance for energy recovery. <P>SOLUTION: In the two-throw gear pump or motor, two pairs of gear mechanisms engaged with each other are disposed before and behind an integrated casing having an intermediate bulkhead, and a bearing to support a gear shaft of the forward and rear gear mechanisms is provided in the bulkhead, and the gear mechanisms are synchronously rotated. A connection passage to connect flow passage ports corresponding to the gear mechanisms to each other is formed in the intermediate bulkhead, and a check valve is installed in the connection passage. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

  The present invention relates to a dual gear pump or a motor that can be used in various fluid equipment (hydraulic equipment) fields and the like.

  Pumps and motors (fluid machines that function as pumps that output high-pressure liquid when rotational power is applied and function as motors when the high-pressure liquid is input) mainly used in the field of fluid equipment include piston and vane types. Among them, gear pumps or motors, which are simplest, are easy to process, and are economical, are particularly used as fluid devices for driving cargo handling machines. For example, a gear type pump for high pressure is commonly used in a battery forklift which lifts and lowers luggage.

  By the way, in the case of this battery forklift, it has been attempted to operate the gear pump operated for lifting as a hydraulic motor when descending, and thus to drive the electric motor for driving the gear pump as a generator to recover the position energy. I have. In this energy recovery system, the discharge side of the gear pump is connected to a single-acting actuator for a forklift via a hydraulic circuit, and when the load is lowered, the pressure from the actuator (cylinder) is pressed into the gear pump. become. Then, the motor for driving the gear pump is driven as a generator to recover energy. In this case, in order for the motor for driving the gear pump to function as a generator, it is necessary that the tooth tip be rotationally driven in the same direction when the motor drives the gear pump. Therefore, the hydraulic circuit is switched during energy recovery, and the gear pump is always driven to rotate in the same direction.

  On the other hand, there is also a dual gear pump or motor in which two pairs of the same gear mechanism are installed and synchronously rotated to output pressure oil from each pump mechanism. These double gear pumps or motors are also used as fluid devices for driving cargo handling machines.

  However, such an energy recovery type gear pump or motor has a complicated and large-sized system as a whole. In particular, as described above, since the gear pump must be driven to rotate in the same direction at the time of energy recovery, a valve mechanism for switching the hydraulic circuit is installed. In addition, since the same gear mechanism is switched between a pump and a motor, there is a problem that it is difficult to obtain a rotation speed required as a generator because the capacity is the same, and it is difficult to sufficiently recover energy.

  The present invention provides a dual gear pump or motor that solves the above-mentioned problems.

  In the dual gear pump or motor provided by the present invention, two pairs of gear mechanisms meshing with each other are disposed before and after an integral casing having an intermediate partition, and the partition is provided with bearings for supporting the gear shafts of the front and rear gear mechanisms. In a dual gear pump or motor in which both gear mechanisms are synchronously rotated by an electric motor, the electric motor can be driven as a generator, and the intermediate partition has a corresponding one of the two gear mechanisms. A connection path connecting the flow paths is formed, and a check valve is installed in the connection path.

  According to the dual gear pump or motor provided by the present invention, the pressure liquids discharged from the two gear mechanisms are merged and supplied to the actuator side. The power is supplied to only one of the gear mechanisms by the stop valve. For example, when the motor for driving the gear pump is driven as a generator to recover energy, the generator is driven to rotate at high speed. Further, since the check valve is installed on the intermediate partition, the gear mechanism can be prevented from being enlarged.

  Since the dual gear pump or motor provided by the present invention is as described above, the entire gear pump or motor can be made compact. When used as a hydraulic device for potential energy recovery, a dual gear pump or motor with high recovery efficiency is provided.

  Hereinafter, the present invention will be described with reference to embodiments shown in the drawings. The configuration of the dual gear pump or the motor TP provided by the present invention is as shown in the drawing. In particular, FIGS. 1 to 3 are cross-sectional views showing the configuration of a dual gear pump or a motor provided by the present invention. FIG. 1 is a vertical cross section, FIG. 2 is a II-II cross section of FIG. 1, and FIG. FIG. 3 shows a cross-sectional view taken along the line III-III of FIG. 2. As is apparent from these figures, each of the gear mechanisms P1 and P2 is composed of a meshing pair of the gears 4 and 7, and a meshing pair of the gears 8 and 9, and the two pairs of gear mechanisms P1 and P2 1, a housing 2 and a rear cover 3. That is, the housing 2 is provided with an intermediate partition 2W at an intermediate portion for separating the two gear mechanisms. The first gear mechanism P1 is housed in a room formed by a step portion on the left side of the partition wall 2W and the front cover 1, and is formed by a step portion on the right side of the partition wall 2W and the rear cover 3. The second gear mechanism P2 is housed in the room. Reference numeral 12 denotes fixing bolts for integrally fixing the front cover 1, the housing 2 and the rear cover 3.

  The gear 4 is formed integrally with the input / output shaft 4 and supported by the bearing 5 and the bush 6 with respect to the casing. The gear 7 is also formed integrally with the shaft and supported by the bush 6 with the casing. I have. On the other hand, the gear 8 is supported by a bush 6 on the casing on the same axis as the gear 4, but the shaft end of the gear 4 is screwed into the gear 8 and fixed. Therefore, the gear 8 is driven to rotate synchronously with the gear 4. However, the gear 9 is supported on the casing by the bush 6 on the same axis as the gear 7, but is formed separately from the gear 7, and the two gears 7 and 9 are separately provided on the gear 4 and the gear 8, respectively. Followed.

  Note that, as is apparent from the figure, the tooth width of the gear mechanism P1 is larger than the tooth width of the gear mechanism P2, so that the discharge capacity per rotation differs. 4G, 7G, 8G, and 9G indicate teeth. In FIG. 1, reference numerals 10 and 11 denote side plates permanently provided as high-pressure gears. Both side plates 10 and 11 have different configurations as described later. The shafts of the gears 7 and 9 have hollow portions 7K and 9K, and communicate with the right space 3K. The empty space 3K communicates with a low pressure region of a check valve CV described later. Therefore, oil leakage from the roots of the gear is guided from the hollow portions 7K and 9K to the low pressure region of the check valve CV via the empty portion 3K.

  In FIG. 1, the flow path ports of the gear mechanism P <b> 1 are not shown, but flow path ports 13 and 14 are provided in the housing 2 as shown in FIGS. 2 and 3. When the gear mechanism P1 operates as a pump, the flow path port 13 serves as an inflow port and the flow path port 14 serves as a discharge port. Although the flow path port of the gear mechanism P2 is not shown, the flow path indicated by L3 in FIG. 3 corresponds to the discharge port when operating as a pump. That is, in FIG. 3, the flow path L6 of the gear mechanism P2 and the flow path L5 connected to the flow path port 14 of the gear mechanism P1 are connected to form a connecting path. A check valve CV is provided in this connection path. The check valve CV is a valve in which the ball valve body 15 in the retainer 17 is urged against the valve seat 16 by a spring 18, and prevents the flow from the flow path L5 to the flow path L6. Therefore, when the gear mechanisms P1 and P2 function as a pump, only the discharge oil from the gear mechanism P2 flows into the flow path L5, and the pump discharges of the two gear mechanisms P1 and P2 are merged. Reference numeral 19 denotes a spring retainer screwed into the retainer 17 and has a flow portion formed therein. As shown in FIG. 2, the spring retainer 19 has a recess on the upper surface, and can be rotated from the outside so that the elasticity of the spring 18 can be adjusted.

  FIG. 6 schematically shows the structure of the double gear pump or the motor TP. FIG. 6 shows a hydraulic circuit connecting the double gear pump or motor TP with the actuator 23 and the oil tank 24. The hydraulic circuits L1, L2, and L7 are indicated by two-dot chain lines because hydraulic circuits other than those shown are juxtaposed and are omitted. That is, when the two gear mechanisms P1 and P2 rotate in the direction of the arrow to function as a pump, the pressure oil is supplied to the actuator 23 side to cause the actuator 23 to project from the cylinder 22. When the two gear mechanisms P1 receive the supply of pressure oil from the actuator 23 side for energy recovery, the rotation of the gear mechanism P1 is supplied by a circuit (not shown) so as to rotate in the direction of the arrow. In this case, the total oil amount of the capacity of the two gear mechanisms P1 and P2 is supplied, and the gear mechanism P1 (the electric motor 20 functioning as a generator) is rotationally driven at high speed. At the time of this energy recovery, a hydraulic circuit is configured so that the gear mechanism P2 does not receive the supply of the pressure oil and is not driven to rotate. In this way, when the drive motor 20 of the gear pump P1 is driven as a generator, the power supply unit 21 recovers electric energy.

  Further, in the present invention, as is apparent from the above description, the gear mechanism P1 has a high-pressure region in both the flow passage ports 13 and 14, but the high-pressure region is fixed because the gear mechanism P2 always functions as a pump. . Therefore, the side plate 10 and the side plate 11 of each gear mechanism have different configurations. Since the side plate 11 has a predetermined high-pressure area, the high-pressure area recess 11K is provided in a high-pressure area fixed position type as shown in FIGS. 5A and 5B. (A) is the figure which looked at the surface which contacts a side plate with a gear, (C) is the figure which looked at the side plate of this invention from the side which contacts a casing. The other side plate 10 has a configuration corresponding to the high pressure region since both of the flow passage openings 13 and 14 are in the high pressure region. That is, the side plate 10 is as shown in FIG. 4A is a view of the side plate in contact with the gear, FIG. 4B is a longitudinal sectional view of the center of FIG. 4A, and FIG. It is the figure seen from the side which contacts.

  As shown in these figures, the side plate 10 has a gourd shape as in the prior art, but is different in that both circular shapes of the gourd shape are formed in a perfect circle except for the gear meshing portion. The side plates cover the entire area around the tooth tip on the side surfaces in the axial direction of the gears that mesh with each other. A flow portion penetrating from the gear side to the counter gear side is formed in the center of the side plate 10 on the counter meshing side. The flow portion 10H is formed in a crescent shape in order to simplify the processing and to smoothly introduce the hydraulic pressure from the gear side. A cutout portion 10K is formed on the side surface of the gear at the portion where the crescent-shaped through-hole 10H is formed so that high-pressure oil between teeth is smoothly guided by the crescent-shaped through-hole 10H. On the other hand, a groove surrounding the gear shaft including the crescent-shaped through hole 10H is formed on the surface (C) that is immediately joined to the casing opposite to the gear surface, and this groove has a rectangular cross section as shown in FIG. The seal member 26 having an L-shaped cross section is fitted into the groove 10M. The outer peripheral end (outer diameter) of the seal member 25 having an L-shaped cross section fitted into the groove 10M is formed to coincide with the outer peripheral end (outer diameter) of the crescent-shaped through-hole 10H, thereby forming a crescent-shaped through-hole. The hydraulic pressure from the gear after passing through does not enter the outer peripheral end surface of the seal member 25 or the surface joined to the casing. With such a configuration, even when both of the flow path ports 13 and 14 are in the high pressure region, the sealing in the low pressure region and the high pressure region can be reliably performed.

  The gear pump or motor provided by the present invention is as described above, but is not limited to the above and illustrated examples, but includes some modified examples. For example, in the above description, a hydraulic device has been described as an example of a fluid device, but the fluid to be used may be special water other than oil, and is not limited to oil. Further, the connection mechanism between the gear 4 and the gear 8 is a screw connection, but may be a spline connection, and is not limited to the illustrated example. The configuration of the check valve is not limited to, for example, a ball valve body. The shape is not limited to the crescent shape of the distribution part of the side plate, and may be a plurality of circular holes. The dual gear pump or motor of the present invention is effective for energy recovery, but can be used for other ordinary uses, such as for driving a normal hydraulic actuator. The tooth width of the gear mechanism P1 may be the same as the tooth width of the gear mechanism P2. The present invention covers all these modifications.

The double gear pump or motor provided by the present invention is as described above, and is summarized as follows.
1) Two pairs of gear mechanisms meshing with each other are disposed before and after an integral casing having an intermediate partition, and bearings for supporting the gear shafts of the front and rear gear mechanisms are provided on the partition so that both gear mechanisms rotate synchronously. In the dual gear pump or the motor, the intermediate partition is provided with a connecting path connecting the corresponding flow ports of the two gear mechanisms, and a check valve is provided in the connecting path. Pump or motor.

  2) Two pairs of gear mechanisms meshing with each other are arranged before and after an integral casing having an intermediate partition, and bearings for supporting the gear shafts of the front and rear gear mechanisms are provided on the partition so that both gear mechanisms rotate synchronously. In the dual gear pump or motor, a connection path connecting the corresponding flow passage ports of the two gear mechanisms is formed in the intermediate partition, a check valve is installed in the connection path, and an outlet of the check valve is provided. A double-gear pump or motor comprising: a side plate having a seal in which a gear mechanism communicating with a side does not short-circuit between high and low pressures even if either of the flow path ports is in a high pressure range.

  3) Two pairs of gear mechanisms meshing with each other are disposed before and after an integral casing having an intermediate partition, and bearings for supporting the gear shafts of the front and rear gear mechanisms are provided on the partition so that both gear mechanisms rotate synchronously. In the dual gear pump or motor, a connection path connecting the corresponding flow passage ports of the two gear mechanisms is formed in the intermediate partition, a check valve is installed in the connection path, and an outlet of the check valve is provided. The gear mechanism that communicates with the side has a side plate that has a seal that does not short-circuit high or low pressure even if either of the flow path ports is in the high pressure range, and the liquid kneaded from the root communicates with the outlet side of the check valve. A dual gear pump or motor configured to be guided to a low pressure range.

1 is a cross-sectional view illustrating a dual gear pump or a motor according to the present invention. 1 is a cross-sectional view illustrating a dual gear pump or a motor according to the present invention. 1 is a cross-sectional view illustrating a dual gear pump or a motor according to the present invention. FIG. 3 is a view showing a side plate of a dual gear pump or a motor according to the present invention. FIG. 3 is a view showing a side plate of a dual gear pump or a motor according to the present invention. It is a figure showing the system of the hydraulic equipment using the present invention.

Explanation of reference numerals

DESCRIPTION OF SYMBOLS 1 ... Front cover 2 ... Housing 2W ... Intermediate partition 3 ... Rear cover 4, 7, 8, 9 ... Gears 10, 11 ... Side plates 13, 14 ... Flow path port 15 ... Ball valve body 16 ... Valve seat 20 ... Electric motor 21 ... Power supply part 22 ... Cylinder 23 ... Actuator 25, 26 ... Seal member CV ... Check valve

Claims (1)

  Two pairs of gear mechanisms meshing with each other are arranged before and after an integrated casing having an intermediate partition, and bearings are provided on the partition to support the gear shafts of the front and rear gear mechanisms, so that the two gear mechanisms are synchronously rotated by an electric motor. In the dual gear pump or the motor, the motor can be driven as a generator, and the intermediate partition has a connecting path connecting the corresponding flow paths of the two gear mechanisms. A double-gear pump or motor characterized in that a check valve is installed in the pump.

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