JP3505697B2 - Bearing structure of jet pump for small watercraft - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a jet pump used in a water jet propulsion device for a small watercraft, and in particular,
The present invention relates to a bearing structure of an impeller rotating shaft in a jet pump for such a small watercraft.

[0002]

2. Description of the Related Art In a small watercraft, which is generally referred to as a watercraft, as its propulsion drive device, water sucked from a water intake at the front end of the water flow duct is rotated by rotating an impeller in the water flow duct. A water injection propulsion device that injects water from a water injection port at the rear end through a nozzle is provided at the rear part of the bottom of the hull, and the so-called jet pump structure is formed near the impeller storage part of such a water flow duct. There is.

In the jet pump of such a water jet propulsion apparatus, the rotary shaft of the impeller is arranged on both front and rear sides of a bearing housing formed inside the jet pump, near the rear end of the shaft behind the impeller. Although supported by bearings, as a bearing portion structure of such an impeller rotating shaft, a structure as shown in FIG. 4 is conventionally known.

In the bearing structure as shown in FIG. 4,
First, the bearing housing 34 in a state in which the seal member is held by the front seal portion 37 and the front bearing 35 is held behind the seal portion 37 is provided outside the front end portion of the bearing housing 34 after the impeller hub portion 18a. After joining with the impeller 18 so that the ends overlap, the rotary shaft 12
Is inserted from the rear of the bearing housing 34, and the rotary shaft 12
The spline engagement of the hub portion 18a of the impeller, the front end step portion of the large diameter portion 12c of the rotary shaft 12 is brought into contact with the rear end portion of the front bearing 35, and then the rear bearing is inserted into the bearing housing 34 from the rear. 36 is inserted, the front end of the rear bearing 36 is brought into contact with the rear end step of the large diameter portion 12c of the rotary shaft, and then the cover member 39 is attached to the rear end of the bearing housing 34 with the bolt 40. As described above, all the assembling work of the part is performed from the rear.

[0005]

By the way, in a jet pump for a small watercraft, the impeller and a bearing housing located behind the impeller are usually arranged such that the rear end of the hub of the impeller is located at the front end of the bearing housing. It is arranged so as to overlap from the outside, and a seal portion for sealing the bearing housing is provided inside the front end portion of the bearing housing.In such a jet pump, the maximum outer diameter of the hub portion of the impeller is provided. Is undesirably increased because it increases the resistance to water flow through the impeller.

However, if a structure is adopted in which the bearing (particularly with respect to the front side bearing) arranged in the bearing housing is assembled into the bearing housing through the seal portion on the front side of the bearing housing, the diameter of the seal portion becomes large. The outer diameter of the front end portion of the bearing housing becomes large, and the maximum outer diameter of the hub portion of the impeller that overlaps with the front end portion becomes unnecessarily large, and the seal member itself attached to the seal portion is also large. Will be needed.

Therefore, the structure shown in FIG. 4 is adopted so that the bearings on both sides can be mounted from the rear of the bearing housing during the assembling work of the relevant portion. However, in such a conventional bearing portion structure, First, the front bearing receives all of the runout of the impeller rotating shaft due to the bending and the thrust caused by the movement of the impeller rotating shaft in the axial direction (front direction). Since only the position is held, a large difference occurs in the load applied to both bearings, the front bearing is consumed much, and the durability of the entire bearing portion deteriorates.

An object of the present invention is to eliminate the above-mentioned inconveniences of the conventional bearing structure of the jet pump for a small watercraft, and more specifically, all the bearings in the bearing housing during assembly. The diameter of the front seal part of the bearing housing can be made smaller so that the hub part of the impeller can be prevented from becoming unnecessarily large and the rear bearing of the bearing housing can be used to mount the impeller. A bearing structure for a jet pump for a small watercraft, which receives the thrust of a rotating shaft and distributes the load on the bearings to both bearings, thereby improving the durability of the entire bearing. The purpose is to do.

[0009]

SUMMARY OF THE INVENTION In order to solve the above problems and achieve the object, the present invention, as described in claim 1 above, rotates an impeller housed inside a jet pump. The shaft is located in front of the front bearing in the bearing structure of the jet boat for a small watercraft, which is supported by bearings arranged on the front and rear sides of the bearing housing formed behind the impeller inside the jet pump. The outer diameter of the seal part of the bearing housing is smaller than the outer diameter of the front bearing,
The outer diameter of the impeller rotating shaft located between the two bearings is less than or equal to the inner diameter of the front bearing, and a collar member that is separate from the bearing housing is placed between the outer rings of both bearings. A member that comes into contact with the rear end of the inner ring of the bearing is detachably fixed to the impeller rotating shaft from the rear end.

Further, in such a bearing structure of a jet pump for a small watercraft, as described in claim 2, the inner diameters of the front bearing and the rear bearing having substantially the same outer diameter are the same as each other. The rear bearing is smaller than that of the rear bearing, and the outer diameter of the impeller rotating shaft in the portion located between the both bearings is larger than the inner diameter of the rear bearing.

[0011]

[Operation] With the above configuration, when assembling the bearing, the bearings on both sides can be mounted in the bearing housing without passing through the seal on the front side of the bearing housing. Since it can be made small, the maximum outer diameter of the boss portion of the impeller that overlaps the outside of the relevant portion does not become larger than necessary.

[0012] After the bearing is assembled, the deflection of the impeller rotating shaft is received by the front bearing, but the thrust due to the movement of the impeller rotating shaft in the axial direction (front direction) is absorbed by the rear bearing. Since it is received by the rear bearing via the contact member fixed to the rear end of the inner ring, that is, the load in the direction perpendicular to the impeller rotation axis is received by the front bearing and the thrust is received by the rear bearing. Therefore, the load applied to the bearing portion by the movement of the impeller rotating shaft is distributed to the front bearing and the rear bearing.

According to the second aspect of the invention, the rear bearing stops the impeller rotating shaft from moving backward, so that the impeller rotating shaft can be reliably positioned with respect to the bearing portion. Becomes

[0014]

Embodiments of the bearing structure of a jet pump for a small watercraft according to the present invention will be described below with reference to the drawings.

FIG. 1 shows an outline of a small watercraft using a jet pump to which the bearing structure of the present invention is applied. The small watercraft 1, which is generally called a watercraft, has a hull. 2 is a bath-shaped hull 3 and deck 4
And a steering handlebar 5 on the bow side (front side) of the deck 4 so that the rider can operate the boat while straddling the seat and gripping the handlebar. The seat 6 is installed on the stern side (rear side) of the deck 4.

The inside of the hull 2 of the small watercraft 1 is divided into a front inside and a rear inside by a partition wall 7 provided in the width direction of the hull near the center in the front-rear direction. , A fuel tank 8 and an engine 9 are housed, and a plurality of cylinders (two or three cylinders) are arranged in the front-rear direction of the hull, from a two-cycle parallel multi-cylinder engine 9 toward the rear (stern side). The output shaft 10 is projected,
An impeller rotating shaft 12 is connected to the output shaft 10 via a coupling 11.

At the rear part of the hull 2 of the small watercraft 1, a hull 3 itself has a recess 13 which is recessed upward from the bottom surface toward the inside of the hull so as to extend in the longitudinal center of the hull in the anteroposterior direction to the stern end. Is formed, and in the recess 13,
The impeller 1 is internally provided via the duct inlet member 16.
A jet pump 17 having a built-in nozzle 8 is installed, and a nozzle 19 is attached to the rear end of the jet pump 17 having the water ejection port 15b opened so as to be able to swing to the left and right.

A coupling 1 is attached to the output shaft 10 of the engine 9.
Impeller rotating shaft 12 whose one end is connected via 1
Is supported by a bearing member 21 fixed to the partition wall 7 in the middle thereof, and is provided in a rear portion of the inside of the hull 2 with a shaft storage cylinder 22.
It passes through the inside, penetrates the hull 3 at the forward inclined portion 13a of the recess 13, and the other end extends inside the jet pump 17, so that the impeller 18 integrally rotates near the rear end of the impeller rotating shaft 12. It is installed.

In the rear horizontal portion 13d of the recess 13 in which the jet pump 17 is installed, the lower portion is closed by the ship bottom plate 20 so as to be substantially flush with the bottom of the hull 3, and the rear of the recess 13 is closed. Is the jet pump 17
It is opened to extend the rear end of the nozzle 19 attached to the outside.

In the small watercraft 1 as described above,
The water jet propulsion device 14 serving as the propulsion drive device is installed in the recess 13 of the hull 3 with the duct inlet component 16 connected to the front end of the jet pump 17 to which the nozzle 19 is attached. Is formed,
The water flow duct 15 through which the water jetted from the water jet port 15b through the nozzle 19 flows is formed by the forward inclined portion 13a of the recess 13.
And the housing of the jet inlet component 16 and the jet pump 17.

That is, the water inlet 15a of the water flow duct 15 is defined by the lower edge of the front inclined portion 13a of the recess 13 and the front edge of the duct inlet member 16, and is accommodated in the rear horizontal portion 13d of the recess 13. The rear end opening of the housing of the jet pump 17 is the water jet port 15 of the water flow duct 15.
It is b.

In the small watercraft 1 having the water jet propulsion device 14 having the above-described structure, the impeller rotating shaft 12 is rotated from the output shaft 10 via the coupling 11 by the drive of the engine 9, and the jet pump 17 is operated. Impeller 1
8 is rotated to suck water into the water flow duct 15 from below the hull through the water suction port 15a, and the sucked water is jetted rearward through the nozzle 19 while being pressurized from the water jet port 15b of the jet pump 17. As a result, the boat 1 is moved forward by the jet reaction force of the jet water, and the rider on the board turns the steering handle 5 left and right, interlocking with the rotation of the steering shaft (not shown) following the steering handle 5. By rotating the nozzle 19 left and right, the jetting direction of the jet water is changed to change the traveling direction of the boat 1.

FIG. 2 shows a portion of the water jet propulsion device 14 in such a small watercraft 1, in which the concave portion 13 of the hull 3 in which the water jet propulsion device 14 is provided has a concave state upward. A front slanted portion 13a that becomes gradually deeper, a fitting portion 13b formed at the rear end of the front slanted portion 13a, and a step portion 13c that expands a concave state outward at the rear end of the fitting portion 13b.
And the rear horizontal portion 13 extending rearward from the outer end of the step portion 13c.
and d.

With respect to the recess 13 of such a hull 3, the lower portion of the annular portion 16a is the inlet component portion 16b of the water flow duct.
The fitting portion 1 of the recess 13 is formed so that the duct inlet component member 16 extending to the water inlet 15a forms the front portion of the water flow duct 15 together with the front inclined portion 13a of the recess 13.
The jet pump 17 having the annular portion 16a fitted to 3b is fitted with the front portion thereof, and the jet pump 17 incorporating the impeller 18 has the front end portion at the rear end of the duct inlet component member 16 (the rear portion of the annular portion 16a). The recessed part 1
3 in the rear horizontal portion 13d.

It should be noted that the water inlet 15a of the water flow duct 15 defined by the lower edge of the forward inclined portion 13a of the recess 13 and the front edge of the duct inlet member 16 contains dust, seaweed, etc. in the water flow duct 15. A grid-like plate 25 is fitted to prevent being sucked.

The jet pump 17 has a housing composed of three members, a substantially cylindrical front member 31 and a central member 32, and a rear member 33 having a rear end having a reduced diameter, both ends of which are open. Each member 31 and 3
The reference numerals 2 and 33 are detachably connected to each other by bolts or the like.

The impeller 18 is housed inside the front member 31 of the jet pump housing, and the bearing housing 34 of the impeller rotating shaft 12 is integrally formed inside the central member 32 and the stationary blades are provided. Nozzle 19 is attached to the rear member 33, which is provided with 28 and whose rear end is reduced in diameter and is opened as the water injection port 15b, so as to surround the water injection port 15b from the outside so that the nozzle 19 can swing horizontally. There is.

Regarding the connection of the housing members 31, 32, 33 of the jet pump 17, although the specific structure thereof is not particularly shown, for example, each member is placed at a proper position on the outer peripheral surface of each member. This can be achieved by an appropriate means such as providing a connecting protrusion so that they overlap in the connecting direction when assembled, and tightening the protrusions of each member together with a single bolt.

FIG. 3 shows a portion of the jet pump 17 of the water jet propulsion device 14. The rear end portion of the impeller rotating shaft 12 extending into the housing of the jet pump 17 is integrally formed with the central member 32. Bearings 3 installed in front and rear of the formed bearing housing 34, respectively.
5, 36 are supported as bearings, a seal portion 37 having double seal members is provided at the front end of the bearing housing 34, and the rear end of the bearing housing 34 is
Cover 3 fixed to bearing housing 34 with bolts 40
Closed by 9.

In front of the bearing housing 34, the hub portion 18a of the impeller 18 housed inside the front member 31 rotates integrally with the impeller rotating shaft 12, so that the hub portion 18a of the impeller 18 is splined. Joint section 12
The rear end portion of the hub portion 18a of the impeller 18 overlaps with the front end portion of the bearing housing 34 provided with the seal portion 37 from the outside.

Although not shown, the jet pump 17 having the impeller 18, the bearings 35, 36, etc. provided in the housing formed of the respective members 31, 32, 33 is integrated with the rear outer peripheral portion of the housing front member 31. By means of a mounting hole penetrating the mounting portion formed in the longitudinal direction of the hull, the mounting portion is fixed to the recess 13 of the hull 3 by a bolt inserted from the rear of the hull.

By the way, the jet pump 1 as described above is used.
The bearing portion of the impeller rotating shaft 12 in FIG. 7 and each part of the impeller rotating shaft 12 corresponding thereto will be described in more detail below.

The outer diameter of the portion 12b of the impeller rotary shaft 12 corresponding to the positions of the seal portion 37 and the front bearing 35 in the bearing housing 34 is larger than the general outer diameter of the impeller rotary shaft 12 outside the bearing housing 34. The outer diameter of the seal portion 37 of the bearing housing 34 located at that portion is considerably smaller than the outer diameter of the front bearing 35.

Both bearings 3 of the impeller rotating shaft 12
The outer diameter of the portion 12c located between the five and 36 is larger than the outer portion of the bearing housing 34 of the impeller rotating shaft 12, but is less than or equal to the inner diameter of the front bearing 35, that is, the inner diameter of the front bearing 35. Equal to or less than.

The outer diameters of the front bearing 35 and the rear bearing 36 are substantially the same, but in this embodiment, the inner diameter of the rear bearing 36 is smaller than that of the front bearing 35. The inner diameter of the rear bearing 36 is smaller than the outer diameter of the portion 12c of the impeller rotating shaft 12 located between the bearings.

The front end of the outer ring of the front bearing 35 abuts on the vertical surface 34a formed behind the seal portion 37 of the inner peripheral wall of the bearing housing 34, and the rear bearing 3
The front end of the inner ring of 6 is in contact with the step between the portion 12d corresponding to the rear bearing 36 of the impeller rotating shaft 12 and the front portion 12c thereof, while the bearings 34, 36 A collar member 38, which is separate from the bearing housing 34, is disposed between the outer rings, and both ends of the collar member 38 are in contact with the outer rings of the front bearing 35 and the rear bearing 36, respectively. Positioning between the bearings 35 and 36 is performed by the.

Further, the rear end portion 12e protruding rearward from the rear bearing 36 of the impeller rotating shaft 12 is a portion 1 corresponding to the rear bearing 36 of the impeller rotating shaft 12.
The diameter is smaller than 2d, and a screw is formed on the outer peripheral surface thereof, and the ring-shaped contact member 43 is fitted into the inner ring of the rear bearing 36, and the rear end portion 12e.
The contact member 43 is detachably fixed to the rear end portion 12e of the impeller rotation shaft 12 by screwing the nut 44 onto the screw.

According to the bearing structure of the jet pump for a small watercraft according to this embodiment having the above-mentioned structure, the bearings 35 and 36 on both sides are assembled when the bearing is assembled.
The seal portion 3 provided on the front side of the bearing housing 34.
It can be mounted in the bearing housing 34 from the rear side without passing through the sealing member 3 of the bearing housing 34.
Since the outer diameter of 7 can be made smaller than the outer diameter of each of the bearings 35 and 36, the maximum outer diameter of the boss portion 18a of the impeller 18 that overlaps the outside of that portion does not become larger than necessary. .

After assembly of the bearing portion, the deflection of the impeller rotating shaft 12 causes the deflection of the shaft, that is, the load in the direction perpendicular to the impeller rotating shaft 12, is received by the front bearing 35. Thrust due to the movement of the impeller rotating shaft 12 in the axial direction (forward direction) is
After being transmitted to the inner ring of the rear bearing 36 via the contact member 43 fixed to the rear end portion 12e of the impeller rotating shaft 12 by the nut 44, the outer ring of the rear bearing 36, the collar member 38, and the front bearing 35 Since it is received by the rear bearing 36 by being transmitted to the bearing housing 34 via the outer ring, the load applied to the bearing portion by the movement of the impeller rotating shaft 12 is distributed to the front bearing 35 and the rear bearing 36, The durability of the bearing as a whole is improved.

Further, in this embodiment, the portion 12c located between the bearings 35 and 36 of the impeller rotating shaft 12 is located.
Since the outer diameter of is larger than the inner diameter of the rear bearing 36, the rear bearing 36 stops the impeller rotating shaft 12 from moving rearward at the rear end step of the impeller rotating shaft portion 12c. Therefore, the impeller rotating shaft 12 can be reliably positioned with respect to the bearing portion.

[0041]

According to the bearing structure of the jet pump for a small watercraft according to the present invention as described above, all the bearings can be mounted from the rear of the bearing housing during assembly, and the front seal of the bearing housing can be mounted. By reducing the diameter of the part, it is possible to avoid the diameter of the hub part of the impeller from becoming larger than necessary, and at the same time, the front bearing receives the load in the direction perpendicular to the impeller rotation axis and the thrust is applied to the rear side. Since the load is received by the bearing and the load applied to the bearing portion by the movement of the impeller rotating shaft is distributed to the front bearing and the rear bearing, the durability of the entire bearing portion can be improved.

[Brief description of drawings]

FIG. 1 is a cross-sectional side view schematically showing a small watercraft (watercraft) to which the bearing structure of a jet pump of the present invention is applied.

FIG. 2 is a cross-sectional side view showing a portion of a water jet propulsion device of the small watercraft shown in FIG.

FIG. 3 is a sectional side view showing a jet pump portion of the water jet propulsion device shown in FIG.

FIG. 4 is a cross-sectional view showing a bearing structure of a conventional jet pump.

[Explanation of symbols]

1 Small watercraft 12 Impeller rotating shaft 17 Jet pump 18 impeller 34 Bearing housing 35 front bearing 36 Rear bearing 37 Seal part 38 Color member 43 Contact member

─────────────────────────────────────────────────── ─── Continuation of the front page (58) Fields investigated (Int.Cl. ⁷ , DB name) F16C 19/00-19/06 F16C 19/56 F16C 35/06 B63H 11/08

Claims (2)

(57) [Claims] 1. A small waterborne vehicle in which a rotary shaft of an impeller housed inside a jet pump is supported by bearings arranged on both front and rear sides of a bearing housing formed behind the impeller inside the jet pump. In the bearing structure of the boat jet pump, the outer diameter of the seal portion of the bearing housing located in front of the front bearing is smaller than the outer diameter of the front bearing,
The outer diameter of the impeller rotating shaft located between the two bearings is less than or equal to the inner diameter of the front bearing, and a collar member that is separate from the bearing housing is placed between the outer rings of both bearings. A bearing structure of a jet pump for a small watercraft, wherein a member that abuts a rear end portion of an inner ring of the bearing is detachably fixed to an impeller rotating shaft from a rear end thereof. 2. The front bearing and the rear bearing, which have substantially the same outer diameter, have a smaller inner diameter in the rear bearing than in the front bearing, and the outer diameter of the impeller rotating shaft in the portion located between the both bearings. Is larger than the inner diameter of the rear bearing, the bearing portion structure of the jet pump for a small watercraft according to claim 1, wherein