JP2024047860A - Hydraulic Pump Structure - Google Patents

Abstract

[Problem] To prevent cavitation from occurring even when a hydraulic pump 10 is operated at high revolutions, and to ensure sufficient anticipated pressure and anticipated amount as designed. [Solution] The hydraulic pump structure of the present invention includes a pump casing 80 in which a pump input shaft 13 is rotatably supported, and a hydraulic pump 10 provided at a portion of the pump input shaft 13 within the pump casing 80. The hydraulic pump 10 is configured separately into a first pump 11 and a second pump 12. The pump casing 80 is formed with a common branch oil passage 93 that branches and sucks hydraulic oil into both the first pump 11 and the second pump 12, and a common merging oil passage 94 that merges hydraulic oil discharged from both the first pump 11 and the second pump 12. [Selected Figure] Figure 5

Description

This invention relates to a hydraulic pump structure, and in particular to one used to supply hydraulic oil to hydraulic clutches in a dual clutch transmission.

Dual clutch transmissions equipped on utility vehicles and work vehicles have been publicly known, for example as disclosed in Patent Document 1.

The dual clutch transmission is constructed by housing an odd-speed (1st, 3rd, etc.) gear group, an even-speed (2nd, 4th, etc.) gear group, a first clutch that connects and disconnects the power transmission to the odd-speed gear group, and a second clutch that connects and disconnects the power transmission to the even-speed gear group. By alternately connecting and disconnecting the first clutch and second clutch, smooth gear changes are achieved, such as from 1st to 2nd and from 2nd to 3rd, while the power is transmitted without interruption.

The dual clutch transmission is equipped with a hydraulic pump as a hydraulic source for controlling each clutch and for lubrication. The hydraulic pump is configured to be driven by the power of the engine, which is the drive source of the dual clutch transmission. The hydraulic oil discharged from the hydraulic pump is supplied to operate each clutch, operate the actuator for the gear shifter, and also lubricate each part.

Patent No. 4941833

The hydraulic pump used in a dual-clutch transmission increases its hydraulic oil discharge volume in proportion to the engine speed, and since it is necessary to ensure a sufficient hydraulic oil discharge volume, there is a demand for a high-capacity hydraulic pump.

However, there was concern that simply increasing the capacity of the hydraulic pump would cause cavitation inside the hydraulic pump when it was operated at high speed, resulting in a plateau in the amount of hydraulic oil discharged and making it impossible to ensure the expected pressure and volume at the design target.

The technical objective of the present invention is to provide a hydraulic pump structure that has been improved upon by examining the current situation as described above.

The invention of claim 1 is a hydraulic pump structure including a pump casing in which a rotating shaft is rotatably supported, and a hydraulic pump provided on a portion of the rotating shaft within the pump casing, the hydraulic pump being separated into a first pump and a second pump, and the pump casing is formed with a common branch oil passage for branching hydraulic oil to both the first pump and the second pump for inhalation, and a common merging oil passage for merging hydraulic oil discharged from both the first pump and the second pump.

In the hydraulic pump structure of the present invention, the common branch oil passage may be located on one side of the pump casing across the rotating shaft and between the first pump and the second pump, and the common merging oil passage may be located on the other side of the pump casing across the rotating shaft and between the first pump and the second pump.

In the hydraulic pump structure of the present invention, the pump casing is split into two parts, a first oil passage plate that houses the first pump and a second oil passage plate that houses the second pump, the rotating shaft extends in the overlapping direction of the first oil passage plate and the second oil passage plate, and penetrates the first oil passage plate and the second oil passage plate, and the common branch oil passage and the common merging oil passage may be formed on the overlapping surface of the first oil passage plate and the second oil passage plate.

According to the present invention, the hydraulic pump is separated and the capacity of the pump alone is reduced, while a sufficient amount of hydraulic oil is discharged overall. Therefore, even when the hydraulic pump is operated at high speed, cavitation can be prevented and the expected pressure and amount as designed can be sufficiently secured. In addition, the oil passage structure can be prevented from becoming complicated, and the hydraulic pump structure can be made more compact.

FIG. 2 is a skeleton diagram showing a power transmission system of a dual clutch transmission. FIG. 2 is a hydraulic circuit diagram of the dual clutch transmission. FIG. 2 is a side view of the dual clutch transmission. FIG. 2 is an exploded perspective view of the dual clutch transmission. FIG. 2 is an exploded perspective view of the hydraulic pump structure as seen from one side. FIG. 4 is an exploded perspective view of the hydraulic pump structure as seen from the other side. FIG. 7 is a cross-sectional view taken along line VII-VII of FIG.

Below, an embodiment of the present invention will be described with reference to the drawings. First, the power transmission system of a dual clutch transmission 2 (hereinafter abbreviated as transmission 2) mounted on a utility vehicle 1 will be described with reference to the skeleton diagram in Figure 1.

As shown in FIG. 1, a hydraulic pump 10 is provided in a housing 3 of a transmission 2 mounted on a utility vehicle 1, which supplies hydraulic oil to a first clutch 25 and a second clutch 26, which will be described later. In this embodiment, the hydraulic pump 10 is separated into a first pump 11 and a second pump 12, and a pump input shaft 13, which is the input shaft of the transmission 2, passes through both the first pump 11 and the second pump 12. One end of the pump input shaft 13 is interlocked with an output shaft 5 of an engine 4, which is the drive source of the utility vehicle 1.

The hydraulic pump 10 (first pump 11 and second pump 12) is therefore driven by the rotation of the pump input shaft 13 based on the power of the engine 4. The power of the engine 4 drives the hydraulic pump 10, and the first clutch 25, second clutch 26, etc. are actuated by receiving the hydraulic oil discharged from the hydraulic pump 10. The pump input shaft 13 corresponds to the rotating shaft described in the claims.

The transmission 2 includes, within the housing 3, the hydraulic pump 10 and pump input shaft 13 described above, as well as a first clutch shaft 14, a second clutch shaft 15, a transmission intermediate shaft 16, a forward/rearward drive shaft 17, and a counter shaft 18, all of which extend parallel to the pump input shaft 13.

An input gear 21 is fixed to the other end of the pump input shaft 13. A first clutch gear 23 fixed to the first clutch shaft 14 and a second clutch gear 24 fixed to the second clutch shaft 15 are engaged with the input gear 21 via an idle gear 22. In the embodiment, both the first clutch gear 23 and the second clutch gear 24 are engaged with the idle gear 22, but the first clutch gear 23 and the second clutch gear 24 are not engaged with each other.

A first clutch 25 that connects and disconnects the power transmission from the pump input shaft 13 to the first clutch shaft 14 is provided on the upstream side of the power transmission of the first clutch shaft 14. A second clutch 26 that connects and disconnects the power transmission from the pump input shaft 13 to the second clutch shaft 15 is provided on the upstream side of the power transmission of the second clutch shaft 15.

The first clutch 25 is located downstream of the first clutch gear 23 on the first clutch shaft 14 in terms of power transmission, and the second clutch 26 is located downstream of the second clutch gear 24 on the second clutch shaft 15 in terms of power transmission.

On the first clutch shaft 14, downstream of the first clutch 25 in terms of power transmission, a fifth-speed gear 31, a seventh-speed gear 33, a third-speed gear 29, and a first-speed gear 27 are arranged in this order from the left in FIG. 1. In this embodiment, the fifth-speed gear 31, the seventh-speed gear 33, and the third-speed gear 29 are rotatably fitted to the first clutch shaft 14. The first-speed gear 27 is fixed to the first clutch shaft 14.

A 5-speed/7-speed shifter 37 that cannot rotate relative to the first clutch shaft 14 and can slide in the axial direction is fitted between the 5-speed gear 31 and the 7-speed gear 33 of the first clutch shaft 14. A 3-speed shifter 35 that cannot rotate relative to the first clutch shaft 14 and can slide in the axial direction is fitted between the 3-speed gear 29 and the 1-speed gear 27 of the first clutch shaft 14. The 5-speed/7-speed shifter 37 can be selectively engaged with the 5-speed gear 31 and the 7-speed gear 33 by the drive of the 5-speed/7-speed cylinder 69 described later. The 3-speed shifter 35 is configured to be engaged and disengaged with the 3-speed gear 29 by the drive of the 3-speed cylinder 67 described later.

On the second clutch shaft 15, downstream of the second clutch 26 in terms of power transmission, a sixth-speed gear 32, a fourth-speed gear 30, and a second-speed gear 28 are arranged in this order from the left in FIG. 1. In this embodiment, the sixth-speed gear 32 and the fourth-speed gear 30 are rotatably fitted to the first clutch shaft 14. The second-speed gear 28 is fixed to the second clutch shaft 15.

A 4-speed/6-speed shifter 36 that cannot rotate relative to the second clutch shaft 15 and can slide in the axial direction is fitted between the 6-speed gear 32 and the 4-speed gear 30 on the second clutch shaft 15. The 4-speed/6-speed shifter 36 can be selectively engaged with the 4-speed gear 30 and the 6-speed gear 32 by the drive of the 4-speed/6-speed cylinder 68 described later.

The gear change intermediate shaft 16 is provided with a 5th/6th speed intermediate gear 41, a 7th speed intermediate gear 42, a 3rd/4th speed intermediate gear 40, a 1st speed intermediate gear 38, and a 2nd speed intermediate gear 39, in that order from the left in FIG. 1. In this embodiment, the 5th/6th speed intermediate gear 41, the 7th speed intermediate gear 42, and the 3rd/4th speed intermediate gear 40 are fixed to the gear change intermediate shaft 16. The 1st speed intermediate gear 38 is rotatably fitted to the gear change intermediate shaft 16. The 2nd speed intermediate gear 39 is fitted to the gear change intermediate shaft 16 via a one-way clutch 44.

A first-speed shifter 34 is fitted between the third-speed/fourth-speed relay gear 40 and the first-speed relay gear 38 of the transmission relay shaft 16, and is non-rotatable relative to the transmission relay shaft 16 and slidable in the axial direction. The first-speed shifter 34 is configured to be engageable with and disengaged from the first-speed gear 27 by the drive of the first-speed cylinder 66, which will be described later.

The 5th/6th speed relay gear 41 is always engaged with the 5th speed gear 31 on the first clutch shaft 14 and the 6th speed gear 32 on the second clutch shaft 15. The 7th speed relay gear 42 is always engaged with the 7th speed gear 33 on the first clutch shaft 14. The 3rd/4th speed relay gear 40 is always engaged with the 3rd speed gear 29 on the first clutch shaft 14 and the 4th speed gear 30 on the second clutch shaft 15. The 1st speed relay gear 38 is always engaged with the 1st speed gear 27 on the first clutch shaft 14. The 2nd speed relay gear 39 is always engaged with the 2nd speed gear 28 on the second clutch shaft 15.

A forward/reverse input gear 45 is fixed to the forward/reverse shaft 17, which is fixed to the forward/reverse input gear 45 on the forward/reverse shaft 16. On the forward/reverse shaft 17, the forward/reverse input gear 45, forward gear 46, and reverse gear 47 are arranged, in order from the left side of FIG. 1. The forward gear 46 and reverse gear 47 are rotatably fitted to the forward/reverse shaft 17. A forward/reverse shifter 48 is fitted between the forward gear 46 and reverse gear 47 of the forward/reverse shaft 17, which cannot rotate relative to the forward/reverse shaft 17 and can slide in the axial direction. The forward/reverse shifter 48 can be selectively engaged with the forward gear 46 and the reverse gear 47 by the drive of the forward/reverse cylinder 62, which will be described later.

The forward gear 46 on the forward/rearward shaft 17 is constantly engaged with a rear wheel counter gear 49 fixed to the counter shaft 18. The rear wheel counter gear 49 is interlocked with the rear wheel differential gear mechanism 19. The reverse gear 47 on the forward/rearward shaft 17 is constantly engaged with a front wheel counter gear 50 fixed to the counter shaft 18 via a reverse gear 51. The front wheel counter gear 50 is interlocked with the front wheel differential gear mechanism (not shown) via the front wheel output mechanism 20.

The power transmitted from the output shaft 5 of the engine 4 to the pump input shaft 13 is appropriately changed in speed by the first clutch shaft 14 or the second clutch shaft 15 and the transmission relay shaft 16, and the forward/reverse direction is changed by the forward/reverse shaft 17 before being transmitted to the counter shaft 18. The shift power transmitted to the counter shaft 18 is then transmitted to the front wheel differential gear mechanism (not shown) via the front wheel output mechanism 20 to drive both left and right front wheels (not shown). The shift power transmitted to the counter shaft 18 is also transmitted to the rear wheel differential gear mechanism 19 to drive both left and right rear wheels 6.

Next, the hydraulic circuit structure of the transmission 2 will be described with reference to FIG. 2. The hydraulic circuit 60 of the transmission 2 includes a hydraulic pump 10 that supplies hydraulic oil to the first clutch 25, the second clutch 26, etc. As described above, the hydraulic pump 10 of the embodiment is configured separately into a first pump 11 and a second pump 12, and is driven by the rotation of a pump input shaft 13 based on the power of the engine 4. The hydraulic pump 10 (first pump 11 and second pump 12) is housed in the housing 3 of the transmission 2. The housing 3 of the transmission 2 is also used as a hydraulic oil tank. The hydraulic oil in the housing 3 is supplied to the hydraulic pump 10 (first pump 11 and second pump 12).

The hydraulic pump 10 (first pump 11 and second pump 12) is connected to a forward/reverse switching valve 61 that controls the switching operation of a forward/reverse cylinder 62. The forward/reverse cylinder 62 selectively engages the forward/reverse shifter 48 with the forward gear 46 and the reverse gear 47. The forward/reverse switching valve 61 is connected to a first clutch proportional solenoid valve 63 that operates the first clutch 25 and a clutch selection valve 65 via the forward/reverse cylinder 62. The forward/reverse switching valve 61 is also connected to a second clutch proportional solenoid valve 64 that operates the second clutch 26.

The hydraulic pump 10 (first pump 11 and second pump 12) is also connected to a 1/3 speed switching solenoid valve 70 that controls the switching operation between the 1st speed cylinder 66 and the 3rd speed cylinder 67, a 5/7 speed switching solenoid valve 72 that controls the switching operation of the 5/7 speed cylinder 69, and a 4/6 speed switching solenoid valve 71 that controls the switching operation of the 4/6 speed cylinder 68.

The 1st-speed cylinder 66 engages and disengages the 1st-speed shifter 34 with the 1st-speed gear 27, and the 3rd-speed cylinder 67 engages and disengages the 3rd-speed shifter 35 with the 3rd-speed gear 29. The 4th-6th-speed cylinder 68 selectively engages the 4th-6th-speed shifter 36 with the 4th-speed gear 30 and the 6th-speed gear 32. The 5th-7th-speed cylinder 69 selectively engages the 5th-7th-speed shifter 37 with the 5th-speed gear 31 and the 7th-speed gear 33.

The hydraulic pump 10 (first pump 11 and second pump 12) is also connected to lubrication nozzles 74, 75 that inject oil into each clutch 25, 26 via a lubrication oil pressure adjustment valve 73 (relief valve). The hydraulic circuit 60 also includes an accumulator, a filter, etc.

Next, the hydraulic pump structure employed in the embodiment will be described with reference to Figures 3 to 7. The hydraulic pump structure of the embodiment includes a pump casing 80 in which a pump input shaft 13 serving as a rotating shaft is rotatably supported, and a hydraulic pump 10 provided at a portion of the pump input shaft 13 within the pump casing 80.

The pump casing 80 housing the hydraulic pump 10 is disposed within the housing 3 of the transmission 2. In this embodiment, the housing 3 has at least a main body 7 and a lid 8 that closes the opening of the main body 7, and the pump casing 80 is housed within the opening of the main body 7. With the pump casing 80 and other components housed within, the main body 7 and the lid 8 are fastened together with bolts.

As described above, in the embodiment, the hydraulic pump 10 is separated into the first pump 11 and the second pump 12. The pump casing 80 is divided into two parts, a first oil passage plate 81 that houses the first pump 11 and a second oil passage plate 82 that houses the second pump 12. In this case, the pump input shaft 13 extends in the overlapping direction of the first oil passage plate 81 and the second oil passage plate 82, and penetrates the first oil passage plate 81 and the second oil passage plate 82. The first oil passage plate 81 and the second oil passage plate 82 are bolted to the main body 7 in an overlapping state such that the second oil passage plate side enters the opening of the main body 7 first. The first oil passage plate 81, the second oil passage plate 82, and the main body 7 are fastened together by a plurality of bolts.

The input gear 21 is fixed to the end of the pump input shaft 13 that protrudes outward from the first oil passage plate 81. The rotating shaft of the idle gear 22 is rotatably supported on the first oil passage plate 81. Needless to say, the input gear 21 and the idle gear 22 are constantly meshed. The end of the pump input shaft 13 that protrudes outward from the second oil passage plate 82 penetrates the main body 7 and is interlocked with the output shaft 5 of the engine 4.

The first oil passage plate 81 has an intake oil passage 84 formed therein, which is connected to a common branch oil passage 93 described later. The intake oil passage 84 of the first oil passage plate 81 is connected to the discharge side of a hydraulic oil intake pipe 85 that takes in hydraulic oil in the housing 3. The intake side of the hydraulic oil intake pipe 85 opens toward the inner bottom of the housing 3. A cylindrical filter 86 is provided midway along the length of the hydraulic oil intake pipe 85.

The first pump 11 and the second pump 12 of the embodiment are trochoid pumps that are well known in the art. The first pump 11 has a first outer rotor 87 rotatably mounted in a first oil passage plate 81, and a first inner rotor 88 mounted to mesh with the first outer rotor 87. The second pump 12 has a second outer rotor 89 rotatably mounted in a second oil passage plate 82, and a second inner rotor 90 mounted to mesh with the second outer rotor 89.

In this embodiment, a common suction chamber 91 and a common discharge chamber 92 are formed on the second oil passage plate 82 at locations eccentric to both sides of the axis of the pump input shaft 13 (which may be the rotation center of each inner rotor 88, 90) so as to surround a part of the outer periphery of each inner rotor 88, 90 (see Figures 5 and 6). The common suction chamber 91 and the common discharge chamber 92 are located between the first pump 11 and the second pump 12.

In the embodiment, the common suction chamber 91 and the common discharge chamber 92 are formed on the second oil passage plate 82 side (the side of the overlapping surface 82a described later), but they may be formed on the first oil passage plate 81 side (the side of the overlapping surface 81a described later), or the common suction chamber 91 may be formed on one oil passage plate 81 (82) and the common discharge chamber 92 on the other oil passage plate 82 (81). The common suction chamber 91 and the common discharge chamber 92 may be formed to straddle both oil passage plates 81, 82 (the overlapping surfaces 81a, 82a described later).

When the first and second inner rotors 88, 90 are rotated by the pump input shaft 13, the first and second outer rotors 87, 89 that mesh with them rotate in the same direction as the first and second inner rotors 88, 90. Then, the multiple rotor chambers formed between the first inner rotor 88 and the first outer rotor 87, and between the second inner rotor 90 and the second outer rotor 89 move while changing their volumes, sucking in hydraulic oil from a common suction chamber 91 formed in a range where the volume of each rotor chamber gradually increases, and discharging hydraulic oil from a common discharge chamber 92 formed in a range where the volume of each rotor chamber gradually decreases. Then, hydraulic oil is supplied to various operating parts in the transmission 2.

As shown in Figures 5 and 7, the pump casing 80 is formed with a common branch oil passage 93 that branches hydraulic oil to both the first pump 11 and the second pump 12 for inhalation, and a common junction oil passage 94 that joins hydraulic oil discharged from both the first pump 11 and the second pump 12. The common branch oil passage 93 is located on one side of the pump casing 80 across the pump input shaft 13 and between the first pump 11 and the second pump 12. The common junction oil passage 94 is located on the other side of the pump casing 80 across the pump input shaft 13 and between the first pump 11 and the second pump 12.

The common branch oil passage 93 and the common junction oil passage 94 in the embodiment are formed on the overlapping surface 83 between the first oil passage plate 81 and the second oil passage plate 82. The overlapping surface 83 between the first oil passage plate 81 and the second oil passage plate 82 is described as a concept including both the overlapping surface 81a of the first oil passage plate 81 and the overlapping surface 82a of the second oil passage plate 82. In this case, the common branch oil passage 93 and the common junction oil passage 94 are formed on the overlapping surface 82a of the second oil passage plate 82. The common suction chamber 91 and the common discharge chamber 92 are also formed on the overlapping surface 82a of the second oil passage plate 82.

Of course, the common branch oil passage 93 and the common junction oil passage 94 may be formed on the overlapping surface 81a of the first oil passage plate 81, or the common branch oil passage 93 may be formed on the overlapping surface 81a (82a) of one oil passage plate 81 (82) and the common junction oil passage 94 on the overlapping surface 82a (81a) of the other oil passage plate 82 (81). The common branch oil passage 93 and the common junction oil passage 94 may be formed so as to straddle both overlapping surfaces 81a, 82a. The term "overlap surface portion 83 of the first oil passage plate 81 and the second oil passage plate 82" is used as a general term for these formation positions.

As described above, the discharge side of the hydraulic oil intake pipe 85 is connected to the upstream side of the intake oil passage 84 of the first oil passage plate 81. The downstream side of the intake oil passage 84 is connected to the upstream side of the common branch oil passage 93. The downstream side of the common branch oil passage 93 is connected to the common intake chamber 91. The common intake chamber 91 is connected to each rotor chamber in the range where the volume gradually increases in both pumps 11 and 12. Then, each rotor chamber in the range where the volume gradually decreases in both pumps 11 and 12 is connected to the common discharge chamber 92. The common discharge chamber 92 is connected to the upstream side of the common merging oil passage 94. In addition, a return oil passage 95 is formed on the outer surface (the surface opposite to the overlapping surface 82a) of the second oil passage plate 82, which returns the excess hydraulic oil supplied to the hydraulic pump 10 (first and second pumps 11 and 12) to the inside of the housing 3.

When the inner rotors 88, 90 of both pumps 11, 12 are rotated by the pump input shaft 13, the first and second outer rotors 87, 89 that mesh with them rotate in the same direction as the first and second inner rotors 88, 90, and the multiple rotor chambers formed between the first inner rotor 88 and the first outer rotor 87, and between the second inner rotor 90 and the second outer rotor 89 move while changing their volumes.

The hydraulic oil in the housing 3 is then sucked up from the suction side of the hydraulic oil suction pipe 85 and sent to the common suction chamber 91 via the suction oil passage 84 of the first oil passage plate and the common branch oil passage 93. The hydraulic oil is then sucked into each rotor chamber whose volume gradually increases in both pumps 11 and 12, and the hydraulic oil is discharged from the common discharge chamber 92 into the common junction oil passage 94 from each rotor chamber whose volume gradually decreases in both pumps 11 and 12. The hydraulic oil is then supplied to various operating parts in the transmission 2.

As is clear from the above description and Figures 5 to 7, the hydraulic pump structure includes a pump casing 80 on which the pump input shaft 13 is rotatably supported, and a hydraulic pump 10 provided at a location of the pump input shaft 13 within the pump casing 80. The hydraulic pump 10 is separated into a first pump 11 and a second pump 12. The pump casing 80 is provided with a common branch oil passage 93 for branching and sucking hydraulic oil to both the first pump 11 and the second pump 12, and a common merging oil passage 94 for merging hydraulic oil discharged from both the first pump 11 and the second pump 12. By separating the hydraulic pump 10 into the first pump 11 and the second pump 12, it is possible to reduce the capacity of the pumps 11 and 12 individually and obtain a sufficient amount of hydraulic oil discharged overall. Therefore, even when the hydraulic pump 10 is operated at high speed, it is possible to prevent cavitation from occurring and to fully secure the expected pressure and expected amount as designed. In addition, hydraulic oil can be supplied to both pumps 11, 12 from the common branch oil passage 93, and the hydraulic oil from both pumps 11, 12 can be collected and discharged from the common merging oil passage, which avoids complicating the oil passage structure and allows for a more compact hydraulic pump structure.

In particular, in this embodiment, the common branch oil passage 93 is located on one side of the pump casing 80 across the pump input shaft 13 and between the first pump 11 and the second pump 12, and the common junction oil passage 94 is located on the other side of the pump casing 80 across the pump input shaft 13 and between the first pump 11 and the second pump 12. This allows for a simple configuration that connects the common branch oil passage 93 and the common junction oil passage 94 to both pumps 11, 12, which contributes to reduced manufacturing costs.

Furthermore, the pump casing 80 is divided into two parts, a first oil passage plate 81 that houses the first pump 11 and a second oil passage plate 82 that houses the second pump 12, the pump input shaft 13 extends in the overlapping direction of the first oil passage plate 81 and the second oil passage plate 82, and penetrates the first oil passage plate 81 and the second oil passage plate 82, and the common branch oil passage 93 and the common merging oil passage 94 are formed on the overlapping surface portion 83 of the first oil passage plate 81 and the second oil passage plate 82, which has the advantage that the common branch oil passage 93 and the common merging oil passage 94 can be easily formed.

The configuration of each part in the present invention is not limited to the illustrated embodiment, and various modifications are possible without departing from the spirit of the present invention.

Reference Signs List 2 Dual clutch transmission 3 Housing 4 Engine 5 Output shaft 10 Hydraulic pump 11 First pump 12 Second pump 13 Pump input shaft 21 Input gear 22 Idle gear 60 Hydraulic circuit 80 Pump casing 81 First oil passage plate 81a Overlapping surface 82 Second oil passage plate 82a Overlapping surface 83 Overlapping surface portion 84 Intake oil passage 87 First outer rotor 88 First inner rotor 89 Second outer rotor 90 Second inner rotor 91 Common intake chamber 92 Common discharge chamber 93 Common branch oil passage 94 Common merging oil passage

Claims (3)

A hydraulic pump structure including a pump casing in which a rotating shaft is rotatably supported, and a hydraulic pump provided at a portion of the rotating shaft within the pump casing,
The hydraulic pump is configured separately as a first pump and a second pump,
The pump casing is formed with a common branch oil passage for branching hydraulic oil to both the first pump and the second pump and sucking it in, and a common merging oil passage for merging hydraulic oil discharged from both the first pump and the second pump.
Hydraulic pump structure. the common branch oil passage is located on one side of the pump casing that sandwiches the rotary shaft and between the first pump and the second pump,
The common junction oil passage is located on the other side of the pump casing across the rotary shaft and between the first pump and the second pump.
A hydraulic pump structure according to claim 1. The pump casing is divided into two parts, a first oil passage plate that houses the first pump and a second oil passage plate that houses the second pump,
The rotation shaft extends in a direction in which the first oil passage plate and the second oil passage plate are overlapped, and penetrates the first oil passage plate and the second oil passage plate,
The common branch oil passage and the common junction oil passage are formed on a mating surface between the first oil passage plate and the second oil passage plate.
A hydraulic pump structure according to claim 2.

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